_. _ __L., ‘ OVERDU FINES: “4’ 25¢ per day per it. ‘4 l1”“““\ ‘ gum ugmv MATERIALS: ..,a _' Place in book nturn to name ‘- 'f ”.‘vlm” ‘ clung. from circulation records '7” 1.. ‘ ANALYSIS OF RESIDUAL STORED GRAIN INSECT POPULATIONS IN THE COUNTRY ELEVATOR ECOSYSTEM By Howard Lee Russell A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology 1980 ,- 4) b' .477 // C5 ABSTRACT ANALYSIS OF RESIDUAL STORED GRAIN INSECT POPULATIONS IN THE COUNTRY ELEVATOR ECOSYSTEM By Howard Lee Russell Country elevators are the initial, central collection points for much of the grain harvested in Michigan and as such represent an initial threat of infestation by insects to the grain that passes through them" The present work is a study of the factors which influence the density and distribution of storage insect pOpulations in the residual grain material which accumulates in country elevators. Over 75% of the samples of residual grain material collected during this study were found to be infested with one or more species of stored grain insects. Both biological and environmental factors which are rather unique to residual grain material were shown to influence the density and dis-" tribution of these insects. The most important parameters are shown to be the level of elevator, the site and the type and condition of the grain present in the residual material. ACKNOWLEDGEMENTS I would like to take this opportunity to thank Dr. James E. Bath and the entire Entomology Department - gradu- ate students, faculty, staff and secretaries - for provid- ing an environment which is rich in support, friendship and progressive ideas. To my Major Professor, Dr. Robert F. Ruppel, who took a chance and gave me this opportunity to study under him, I extend my sincerest gratitude for his support, guidance and friendship. To my other committee members, Drs. Edward J. Grafius, James A. Webster, and Roland L. Fischer, I extend my thanks for guidance in their areas of expertise and review of this thesis. To my associates and fellow graduate students, Messrs. Paul Love, Joseph Noling, Tom Ellis, Duane Jokinen and Dr. Emmett Lampert (AHB) and Ms. Amy Brown, I would like to extend my thanks for their ideas and friendship. Also, I would like to extend special thanks to Mr. Steve Gussis- berg who helped in collecting the field data and to Mrs. D. R. Filter for her efforts in preparing this manuscript. To Majorie, my wife, who edited this thesis, I extend my thanks for her help and support throughout my Masters program. ii TABLE OF CONTENTS Page LIST OF TABLES ................................... vi INTRODUCTION ..................................... 1 LITERATURE REVIEW’ ................................ 4 Grain ....................................... 4 Storage Insects ............................. 6 Ecology of Storage Insects .................. l4 Bulk Grain Ecology ..................... 15 Residual Population Ecology ............ 24 Sources of Infestation ...................... 25 Natural Sources ........................ 25 Field Infestations and Insect Migrations ........................ 28 On-farm Sources of Infestations ........ 29 Sources of Infestation in Elevators and Feed Mills .................... 30 Other Sources and Surveys .............. 32 METHODS AND MATERIALS ............................ 35 Preliminary Study ........................... 35 Large Scale Study ........................... 36 Areas of the State and Elevators Sampled.... 36 Parameter and Parameter Category Selection.. 38 Inside and Outside ..................... 38 Level .................................. 39 Site ................................... 39 Structure .............................. 43 Amount of Material ..................... 43 Moisture Content ....................... 44 iii Predominant Grains and Beans Present... Condition of Grain Material ............ Data Collection ............................. Sample Collection ...................... Sample Incubation ...................... Sample Evaluation ...................... The Data File .......................... Analyses .................................... RESULTS...; ...................................... General ................................ Granary Weevil ......................... Cryptolestes ........................... Red Flour Beetle ....................... Confused Flour Beetle .................. Sawtoothed Grain Beetle ................ Yellow Mealworm ........................ Black Carpet Beetle .................... Dark Mealworm .......................... Cadelle Beetle ......................... Larger Black Flour Beetle .............. Drugstore Beetle ....................... Ptinids ................................ Mediterranean Flour Moth ............... Mites .................................. Windowpane Fly ......................... Number of Species ...................... ANOVA Results .......................... Species Combinations ................... Species Correlations ................... DISCUSSION ....................................... CONCLUSIONS ...................................... BIBLIOGRAPHY ..................................... APPENDICES ....................................... Appendix A. Manager Interview Summaries.... Appendix B. Listing of Raw Data ............ Appendix C. Relative Frequency of the Number of Species Collected from Samples ............... Appendix D. Frequency of Species Combinations ............... iV/y Page Table 10. 11. LIST OF TABLES Species commonly found in elevator residual grain material samples ........... Frequency and mean density of GRWV in the areas of the state, elevators and parameter categories ..................... Results of multiple regression analysis of GRWV density .......................... Frequency and mean density of CRYP in the areas of the state, elevators and parameter categories ..................... Results of multiple regression analysis of CRYP density .......................... Frequency and mean density of RDFB in the areas of state, elevators and parameter categories ..................... Frequency and mean density of CNFB in the areas of the state, elevators and parameter categories ..................... Results of multiple regression analysis of CNFB density .......................... Frequency and mean density of SWTH in the areas of the state, elevators and parameter categories ..................... Results of multiple regression analysis of SWTH density .......................... Frequency and mean density of YWMW in the areas of the state, elevators and parameter categories ..................... vi Page 59 61 66 68 73 74 79 84 85 9O 91 Table 12. 13. 14. 15. 16. 17. 18. 19. Bl. D1. Results of multiple regression analysis of YWMW density .......................... Frequency and mean density of BKCB in the areas of the state, elevators and parameter categories ..................... Results of multiple regression analysis of BKCB density .......................... Results of multiple regression analysis of SCNO density .......................... Frequency of common two-way combinations of species in residual grain material samples .................................. Frequency of common three-way combinations of species in residual grain material samples .................................. Pearson's correlation coefficients between insect density and other continuous variables ............................... Summary of One-way Analysis of Variance significant F statistics ................ Raw data from residual grain material samples collected from operating elevators, Summer, 1978 ................. Frequency of all species combinations found in residual grain material samples collected from seventeen Michigan elevators ...................... vii Page 96 97 102 108 115 116 118 119 157 181 INTRODUCTION As soon as grain is harvested in the field, it enters and becomes part of a complex postharvest grain ecosystem. This ecosystem.includes biological, structural, and manage- ment components. The biological components include the grain, insects and mites, microorganisms, and vertebrate pests. Structural components include facilities and ve- hicles employed in the transport, storage, and processing of the grain. The management components include sanitation and maintenance of the structural components, control measures taken to reduce losses due to the biological components, and any other strategy implemented to insure grain quality. Grain in this postharvest ecosystem is a highly mobile entity. As it passes through the various structural com- ponents, very often a minute fraction of the grain is left behind as a result of spills, improper sanitation, or inadew quate construction of these facilities. It is in these res- idual accumulations of grain or grain material that storage insect populations are maintained from one year to the next. Although many storage species have been reported living under bark (Linsley 1944) and in bird nests (Hicks 1959), those found in the postharvest grain ecosystem represent the most econimically important and probably the largest portion of 2 the total population. Residual grain material in combines, trucks, on-farm storage bins, country elevators, railcars, terminal elevators, port warehouses, ships, processing plants, supermarket storerooms, and even the kitchen cupboard can be important sources of infestation. Each one of these struc- tural components has numberous, sometimes unique micro- habitats in which insect populations persist. There is a distinct possibility of an infestation occurring as grain or grain products pass through each of them. Manipulation of these provides the only reasonable long-term solution to the insect problem: namely, drastically reduce the availability of these microhabitats in which populations persist by either altering the structure of the componets or by provid- ing better maintenance of the existing facilities. It is in this context the present study was undertaken. The present work deals with just one structural compon- ent of the postharvest grain ecosystem, the country elevator. These facilities are initial, central collection points for much of the grain and beans harvested in Michigan. Here, the grain is cleaned and dried if necessary, then stored until it is transported to another component.. The elevators studied ranged in size from 9,000 to 1.1 million bushels maximum capacity, were usually constructed of wood and concrete, and consisted of a basement and two or more upper levels with various grain processing machinery located on each level. These facilities were found to provide numerous and varied microhabitats in which insects could be found. The objectives of this study were: 1) to survey the insect species found in residual grain material located in these microhabitats or sites; 2) determine the conditions and sites which are favorable to insect populations; 3) determine some of the factors influencing the distribution and abund- ance of insect populations in and around these facilities; and 4) suggeSt management strategies for reducing pest problems. LITERATURE REVIEW Grain The single most important component of the grain eco- system is the grain itself. Therefore, some discussion of kernel structure is warranted. The following discussion is taken from an excellent paper by Pomeranz and Bechtel (1978). Kernel structure is of great significance in producing, storing, processing, and marketing of all cereal grains. The cereal kernel is a one-seeded fruit called a caryopsis, in which the fruit coat is adherent to the seed. Structurally, the kernel is comprised of three main parts: the hull or bran layers; the endosperm; and the embryo or germ. As the kernel grows in the field, it is protected by the floral en- velopes or chaffy parts which are modified leaves known as the lemma and palea. During harvest, these chaffy parts are easily removed from the grain. The hull or bran layers consist of the first seven cell layers of the kernel. The pericarp or dry fruit coat consists of the first four: the epidermis; the hypodermis; cross cells; and tube cells. The inner bran consists of the next three layers: the seed coat; nucellar tissue; and aleurone layer. The remaining tissues of the grain are the endosperm and embryo. 5 In a well-filled wheat kernel, the germ comprises approximately 2-3 percent of the kernel, the bran 13-17 percent and the starchy endosperm the remainder. In a typical dent-corn kernel, the pericarp comprises about 6 percent, the germ 11 percent and the endosperm about 83 per- cent of the kernel. , In wheat, the outer bran layers are high in cellulose, the hemicelluloses and minerals. The structure and adher- ence of the hull are important in protecting the germinating seed and in the malting process. Also, as result of high silica concentrations in these layers, the attack by storage insects is slowed in rice and barley. The germ is high in proteins, lipids, sugars and minerals. The endosperm con- sists largely of starch granules surrounded by a protein matrix. Cereal grains are important as food because of their ex- cellent keeping qualities. Moisture content is the major factor in determining the storage behavior of grain. Tempera- ture, oxygen supply, history and condition of the grain, length of the storage period, and biological factors such as molds and insects also influence this behavior. The respiratory rate of dry grain is low. As moisture content is raised above 14 percent, the respiratory rate increases gradually until a critical moisture content is reached above which respiration accelerates rapidly and the grain tends to heat. This sharp increase in respiration is due to the germination and growth of certain molds, 6 predominately various species of Aspergillus and Penicill- Egg. These molds are commonly found in the soil and storage bins and are invariably found on the grain and within the seed coats, even if the grain is harvested under ideal con- ditions. Sinha and Wallace (1966) report that insects can also initiate grain heating. Kernel structure has many implications related to processing and end-use. Threshing may cause germ damage or skinning which reduces germination and impairs storability in all cereal grains. Drying grain causes cracks, fissures and breakage to occur, which reduces commercial value and impairs storability. Over-drying causes hardening of the protein matrix surrounding the starch granules which lowers the starch yield when milled. Breakage incurred during transport and marketing reduces the commercial value of rice and corn, and impairs storability of all cereal grains. Finally, kernel shape, tissue proportions, and the distri- bution of nutrients within these tissues affects the yield of food products and the nutritional qualities of these products in all cereal grains. Storage Insects Stored product insect pests can be roughly divided into two groups based on feeding behavior. Species which attack whole grain and whose immatures develop inside the kernel are termed primary pests. Those species which prefer grain particulate and grain in poor condition are termed 7 secondary pests (LeCabo 1975b). These stored product insects share a number of bio- logical characteristics which have combined to bring about their widespread distribution and pest status. These in- sects as a group have a relatively wide range of tolerance for physical factors of the environment, especially moisture. They have a wide range of food habits and many include in their diet the majority of dry food products of animal and plant origin. Adults are usually long-lived and many species reproduce more or less continuously under favorable environ- mental conditions (Linsley 1944). Cotton and Good (1937) listed hundreds of insect species which are associated with stored grain and several authors have written taxonomic keys to aid in their identification: Hinton and Corbet (1955) for most stored-product insects; Hinton (1945) and Arnett (1968) for beetles; Beal (1956) for species of Trogoderma; Bishop (1959b) for Cryptolestes larvae; Corbet, et a1. (1943) for Lepidoptera; and Gahan (1931) and Richards (1949) for parasitic Hymenoptera. Ruppel (1977) listed 40 species of stored-product pests known to be damaging in Michigan. Five orders of insects and one order of mites including 18 families are included in this list. It is not the purpose of this section to present detailed biological information for all those species listed by Ruppel. Only a brief description and biological summary will be given for those species commonly encountered during the present study. The granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae) is the most serious primary pest in Michigan. It prefers temperate climates and is worldwide in distribution. Adults are wingless and about 4mm long with longitudinal punctures present on the thorax. Two closely related species, S; oryzae (L.) and S; zeamaise (Motschulsky), are common pests of whole grain in warmer climates (USDA 1978). Both larvae and adults of the granary weevil feed voraciously on a great variety of grains. Each female will lay between 50-250 eggs. Before an egg is laid, a female will chew a small hole into the seed coat in which the egg is then deposited. The hole is then sealed with a gelatin- ous fluid. Upon hatching the grub burrows about inside the kernel where it completes its development. Under favorable conditions, this weevil requires about four weeks to develop from egg to adult (USDA 1978). Cotton (1963) reported that unlike the rice weevil, S; oryzae, the granary weevil is never found breeding in standing fields of grain. It is restricted to only those habitats found in grain storage or processing facilities. There are three species of Cryptolestes (Coleoptera: Cucujidae) which commonly infest stored products in North America. These are: the rusty grain beetle, 9; ferrugineus (Stephens); the flat grain beetle, 9; minutus (Olivier); 9 and g. turcicus (Grouvelle) (Bishop 1959a). Leng (1920) listed Cryptolestes as a subgenus of Laemophiloeus, which is a heterogeneous group including over 300 species (Rilett 1949). Steel and Howe (1955) elevated those ngmg— philoeus commonly found in stored products into a uniform group Cryptolestes. This revision has been used extensively in recent literature concerning these species. Bishop (1959a) reported 9. ferrugineus as the most abundant of the three in collections from northern grain producing areas in the United States. Howe and Lefkovitch (1958) concluded that g. ferrugineus and g. turcicus are worldwide in distribution, being found in humid and dry areas in both temperate and tropical regions. The range of g. minutus is reported by these authors to be limited by low temperature and low humidity. Cryptolestes species are among the smallest beetles commonly found in stored grain. They are minute, flattened, oblong, reddish-brown beetles about 2mm long. The three species can be distinguished on the basis of the male antennae (USDA.1978), however, no attempt to do so was made during the present study. Female Cryptolestes deposit their eggs into cracks or crevices in the seed coat of whole kernels or, if such sites are not available, loosely in the grain material (Rilett 1949, Bishop 1959a). Rilett (1949) reported that larvae of g. ferrugineus preferred to develop in the burrows created by their feeding inside the kernel with the germ the lO preferred food. Development from egg to adult under favor- able conditions takes about five weeks (USDA 1978). Rilett (1949) also reported 9. ferrugineus to be cannibalistic with the prepupal and pupal stages the usual victims. LeCato (1975b) reported that one species of Cryptolestes reduced numbers of other stored-grain insects in laboratory competit— ion studies. Loschiavo and Sinha (1966) studied the effects of seed-borne fungi on the feeding and oviposition behavior of Q. ferrugineus. The confused flour beetle, Tribolium confusum duVal, and the red flour beetle, Tribolium castaneum.(Herbst) (Coleoptera: Tenebrionidae) are primarily pests of milled or processed foods. Both species are shiny, flattened, oval, reddish-brown beetles about 4mm long. The adults can be distinguished by differences in the terminal segments of the antennae. In the confused.flour beetle, the segments of the antennae gradually increase in size from the base to the appex, whereas the last few segments of the red flour beetle antennae are abruptly larger than the other segments, forming enlarged clubs (USDA 1978). The immature stages are so similar that it is almost impossible to distinguish between them. Both species are cosmopolitan and are often found living together, as they have similar breeding and feeding habits (USDA 1978). Females of both species lay an average of 450 eggs loosely in the food material in which the parents live (Cotton 1963). Under favorable conditions, development 11 from egg to adult takes about six weeks. Adults live about one year (USDA 1978). Park 2; a1. (1965) reported both species to be cannib- istic and LeCato (1975b) found the red flour beetle to be predacious upon the immature stages of several other storage species. Park (1948, 1954) found in laboratory studies that, when T. confusum and T. castaneum are placed together in competition, one of the two always becomes extinct given enough time. The sawtoothed grain beetle, Oryzaephilus surinamenis (L.) (Coleoptera: Silvanidae), is another common pest of stored grain and processed food. The common name reflects the presence of six sawtooth-like projections on each side of the pronotum. A closely related species, the merchant grain beetle, 9, mercator (Fauvel), has similar projections and is often confused with Q. surinamenis. These species can be distinguished by the structure of the head and eyes (Hinton and Corbet 1955). The sawtoothed grain beetle attacks, both as larvae and adults, all food of vegetable origin, especially grain and grain products. Adults live an average of 6 to 10 months and are about 4mm long. Females lay up to 300 eggs loosely into the material on which the adults are feeding. Under favorable conditions, development from egg to adult takes about 4 weeks (Cotton 1963, USDA 1978). 12 Among the largest beetles known to infest stored pro- ducts are the yellow mealworm, Tenebrio molitor L., and the dark mealworm, Tenebrio obscurus Fabricius (Coleoptera: Tenebrionidae). Both species are cosmopolitan but abundant only in northern latitudes. They are often found living to- gether and have similar breeding and feeding habits. Al- though common in grain debris, neither are serious pests (USDA 1978). Adults of these two species can be distinguished on the basis of coloration: T, molitor is a highly polished brown orblack beetle somewhat longer than 13 mm (huge by stored- grain standards); 1. obscurus is similar in size but is a dull, pitch-black beetle (USDA 1978). Unlike the previously mentioned species which may pro- duce two or more generations per year (multivoltine), meal worms have but one generation per year (univoltine). Larvae from eggs laid in late spring or early summer become full grown in about three months. Pupation and adult emergence, however, do not occur until the following spring (USDA 1978). Hatch (1961) reported that there are about 50 dermestid species recorded as pests of stored products. In general, the dermestids are a group of beetles that scavenge and feed on animal material. Certain species belonging to the genera Trogoderma, Anthrenus and Attagenus vary their diets by feeding on farinaceous materials (Hatch 1961). One of the most common species of this group in North America is the black carpet beetle, Attagenus megatoma l3 (Fabricius). Adults of this almost ubiquitous species are small, black, oval beetles about 3 mm long, with yellow antennae and legs. Larvae are very characteristic: they are reddish or golden brown, carrot-shaped, with a tuft of long hairs at the caudal end of the body. Females lay about 100 eggs and, like the mealworms, there is only one generation per year in northern climates (USDA 1978). After mating and egg laying, adults are normally found on flowers, feeding on pollen (Hatch 1961). Other common dermestid species found in stored products are Trogoderma inclusum Le Conte and Trogoderma glabrum (Herbst). These two species are very similar in appearance and are found in similar situations. Beck (1971, 1971b) reported larvae of T. glabrum.will molt to successively smaller sizes (termed retromolt) when deprived of food. Supplied with food, these starved larvae will regrow and complete their life cycles. The cadelle beetle, Tenebroides mauritanicus (L.) (Coleoptera: Trogositidae) is an elongate, flattened, black. beetle about 1 cm. long. Larvae are very characteristic. They are relatively large, fleshy grubs with the abdomen terminating in prominent cerci. The body of a larva is dirty or chalky white with the head, thoracic shield, and cerci black (USDA 1978). This species is also cosmopolitan. Both larvae and adults feed on whole grain and from kernel to kernel l4 devouring the germ. They also do considerable damage to wooden structures by burrowing (Cotton 1963). Linsley (1944) reported that cadelle larvae and adults are both cannibalistic and predacious upon immature stages of other insects. Ecology of Stored Grain Insects Populations of storage insects in the postharvest grain ecosystem can be divided into two types: 1) those contained in the grain mass proper and 2) the ambient population found in residual grain material. The relationship between these populations is one of cause and effect; a population in the grain mass proper is the result of populations existing in close proximity to that grain mass. The ecology of both population types is very complex and dynamic. Indeed, every structural, biotic and management component may influence the quality and quantity of both populations. The two sub- ecosystems in which the grain mass and ambient populations exist are considerably different. The bulk grain popula- tion exists in a more or less unlimited food source which,‘ although temporarily stored on occasion, is very mobile. Ambient populations, however, exist essentially in a limited food Course which is more or less stationary. Ambient papulations are also considerably more permanent than popu- lations in the grain mass which are subject to intense chemical control measures. 15 Bulk Grain Ecology The loss of grain quality resulting from an insect in- festation is caused by direct physical damage to the kernels, which reduces the numerical grade assigned the grain; and/ or by their mere presence in the grain which can result in an additional grade reduction (USDA 1953). The damage done by a particular species is related chiefly to the abundance of that species in the grain (Solomon 1935). The abundance of a species in a grain mass is the result of: l) the initial density of that species in the grain; 2) the length of time those initial insects and their progeny are able to reproduce; and 3) the rate of increase of that species under the existing environmental factors (Solomon 1953). [The initial density of the insect in previously unin- fested grain is undoubtedly a function of the residual pop- ulation density. Solomon (1953) found insect dispersal from a small grain mass to be density dependent. Surtees (1963a, 1963b, 1963c) reported that the proportion of the population found on the surface of the grain, and general insect activ- ity increase as density increases. The probability of a fecund female locating and establishing population is proportional to the density of the residual population, and the length of time that grain is stored. Conversely, the distance that the female must travel to reach the grain and the difficulty of obtaining access into the grain once it is reached reduce this probability. 16 The ability of an incipient population to increase through time, and eventually cause loss of grain quality, is dependent primarily on the physical characteristics of the grain, but is also modified by density effects, disease, predators and parasites, other storage species, and manage- ment practices (Solomon 1953). Temperature and moisture are the most important physical characteristics that influence the abundance of storage species in a large mass of grain. Many authors have reported the effects of these: Rilett 1949 on Cryptol- estes ferrugineus; Park (1954) on Tribolium spp.; Bishop (1959a) on Cryptoles spp.; Cotton, EE.2£- (1953), Solomon (1953), Cotton (1963), Howe (1965) and Atwal (1974) for several common storage pests. Howe (1965) reported the opti- mal temperature range for increase of most common storage species to be 28-0 to 35°C. Howe found much more variation among species in the minimum relative humidity required for population increase. This ranged from 1% required by Tribolium species to 50% for the granary weevil. Solomon (1953) reported that the interaction between grain temper- ature and moisture significantly affects the reproductive potential, developmental rate, and the mortality of insect populations. The temperature and moisture of the grain is influenced by several factors. It is recommended that grain harvested wet be dried to below 15% moisture content before storing l7 (Ruppel 1978). The grain should then be aerated to cool it as much as the season permits (Cotton 1963). Both temp- erature and moisture of the grain are also influenced by seasonal changes in climate. As the seasons change, air movement or convection currents move through the grain mass as a result of the difference in temperature between the grain and the outside air. In the fall, when the grain is warmer than the ambient air, the convection is from the bottom upwards and the grain cools. In the spring, when the grain is cooler than the warming air, convection is from the top downward and the grain warms (Cotton 1963). Insect and mite abundance increase and decrease in response to changes in temperature (Sinha 1974). Condensation of moisture on the surface of the grain results when warm, moist spring air is drawn through to the cooler mass (Cotton 1963). Moisture can also collect on the grain as a result of leaks in the walls and roofs of the facilities used to store and transport the grain (Ruppel 1978). Biotic factors, as reported by Pomeranz and Bechtel (1978) can also cause the grain to heat. The sawtoothed grain beetle and the rusty grain beetle are capable of initia- ting "hot spots" in stored wheat in Canada. These species were also found to increase the moisture content of the grain adjacent to the "hot spots" as a result of the release of metabolic water (Sinha and Wallace 1966). 18 Insect abundance is also influenced by the condition of the grain; condition of grain meaning its relative composition of whole kernels, damaged kernels and grain particulate. Cotton, 35 31. (1953) reported drastic diff- erences in the development of flour beetle populations in whole sound grain only, and in'grain containing added grain particulate. Coombs (1962) found greater numbers of secondary pests in grain residues containing high proportions of grain particulate, and greater numbers of granary weevils in residues containing mostly whole kernels. LeCato (1975a) reported that the sawtoothed grain beetle, red flour beetle, and Cryptolestes produce more progeny in cracked corn than in whole corn. Le Cato (1975a) found that the type of grain also has a pronounced effect on the number of offspring produced by several storage species. In laboratory experiments, the sawtoothed grain beetle; red flour beetle; lesser grain borer, Rhyzopertha dominica; and the rice weevil Sitophilus oryzae, produced more progeny in wheat than in rice. The sawtoothed grain beetle produced more progeny in corn than in rice or wheat. Besides the character of the grain, there are intra- interspecies interactions that appear to influence the abundance of insects in the grain mass. Most research in this area has been restricted to laboratory studies and such effects seem to be perceptible only at higher densities (Solomon 1953). As the density of several storage species 19 increases: 1) their rate of increase decreases; 2) mortal- ity during developmental stages increases; 3) adult size, longevity and egg laying decrease; and 4) dispersal in— creases. Park, gt 31. (1965) found cannibalism in popu- lations of flour beetles to be the main cause of increasedf mortality of develOpmental stages. Competition and interaction among storage species have been studied by numerous authors including: Park (1948) between Tribolium species; Barnes and Simmons (1952) between the sawtoothed grain beetle and Indian meal moth, Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae); Park (1954) between Tribolium.species; Park, 3; 31. (1965) between Tribolium species; Lefkovitch (1968) among rice weevil, rusty grain beetle, red flour beetle and the cigarette beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae); Sunha, 9; a1. (1970) among insects, mites and fungi; Chestnut and Douglas (1971) between the maize weevil, Sitophilus zeamaise and Angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae); LeCato (1975b) among the red flour beetle, sawtoothed grain beetle, flat grain beetle, and Indian meal moth; and Bowker (1979) between Tribolium species. The red flour beetle preys on certain stages of its own species and of the confused flour beetle (Park, g5 31. 1965) and several other stored product moths (Adeyemi 1968) and beetles (LeCato 1975b). The sawtoothed grain beetle feeds on the eggs of the Indian meal moth (Barnes and Simmons 1952). 20 Indian meal moth larvae feed on the immatures stages of Cryptolestes (LeCato 1975b). Maize weevil adults destroy eggs of the Angoumois grain moth by crawling over them which mechanically damages them, Park (1948) reported in laboratory studies the presence or absence of the sporozoan parasite, Adelina triboli, and determined which species of Tribolium became extinct when the species were brought together in competition. Bowker (1979) used caloric determinations to define and quantify interact- ions between T. confusum.and T. castaneum. Bowker reported I. castaneum predates more heavily on T. confusum at 30°C, but at 25°C 3. confusum predates more heavily on T. castaneum. LeCato and Flaherty (1973) reported 1. castaneum progeny pro- duction increased after dead eggs or adults of Indian meal moth were added to the diet. Lefkovitch (1968) found in laboratory studies, that the rice weevil was significantly inhibited by the presence of rusty grain beetles; cigarette beetles were inhabited by rice weevils; red flour beetles were inhibited by rusty grain beetles; and rusty grain beetle numbers increased on whole, sound wheat when any of these other species were present. Other secondary pests are also enhanced by the presence of other insects that are capable of attacking whole, sound grain (Bulla, £5 31. 1978). Only one interaction study was found which was conducted in a bonafide storage facility. It investigated the inter- relationships among insects, mites, microorganisms and 21 grain character. Those fungi listed by Pomeranz and Bechtel (1978) as being carried by seeds from the field were found to disappear under storage conditions and be replaced by other fungal species Sinha, _E‘_1. (1970). Also, the abundance of storage mites was unaffected by time and most fungi, but appeared to be regulated by a complex interaction of temperature and moisture and, in some cases, the depth of the grain bulk. There are hundreds of parasites and obligate predators known to attack stored-grain insect pests (Cotton and Good 1937). Of the hymenopterous parasites which attach Sitophilus spp., the pteromalid, Anisopteromalus calandrae (Howard), is the most important parasite of rice and granary weevils (USDA 1978). Chestnut and Douglas (1971) reported parasitism by.A. calandrae to be about 3% in field populations of the maize weevil in Mississippi. The ichneumonid, Ventura canescens (Gravenhost) and the braconid, Bracon hebetor Say are important parasites of flour and meal moths (USDA 1978). The anthocorid, Xylocoris flavipes (Rueter) (Hemiptera) is considered to be an efficient predator of storage pests because of its ability to destroy large numbers of prey and its ability to feed on a wide variety of prey species and prey stages (LeCato and Collins 1976). The most important factory influencing the number of prey killed by g. flavipes appears to be the size of the prey (LeCato and Davis 1973). This predator may have promise in reducing residual popula- tions but not grain mass pOpulations because it leaves a 22 foul odor in the material in which it is feeding (LeCato, e_t_ a1. 1977). Management practices also have a dramatic effect on the abundance of storage pests in a large grain mass since they determine the structure, construction, procedure and maintenance of the facilities used to store and transport the grain. ‘Grain management, then, ultimately determines the character of grain; e.g. temperature, moisture, condition, and the density of the incipient infestation. If the charac- ter of the grain is maintained such as not be be conducive to insect development, and the residual populations are kept to a minimum, then insect damage would be expected to be reduced. Today's modern storage bins appear to be constructed to aid insect abundance. These facilities are generally constructed with a "false floor" bottom.which provides about a 6 inch space between the concrete foundation and the perforated metal sheeting on which the entire grain mass is supported. Grain and grain particulate that shifts through the perforations and collects on the concrete foundation provides enough food for storage insects to live. Insects, from the "false floor" population, have easy access to the grain mass via the perforations. Grain particulate, resulting from kernels being damaged as the bin is filled, accumulates in the core of the grain mass, which hinders air movement through the grain and provides food for many secondary insect pests. Detection of incipient insect populations within the grain mass is also hindered because probe samples can only be 23 taken from the top 6 feet or so of the mass and, even then, 20 probe samples have only about a 50% chance of detecting a damaging population in the portion of grain sampled (Russell 1978 unpublished). Sampling ports, easily access- ible from the outside of the bin, could be included in the structure of the bins to aid in the detection of a pending insect problem. Chemical control measures have an obvious effect on in- sect populations in the grain mass. Both grain fumigants and grain protectants are recommended to protect the grain from insect damage (Ruppel 1978). Fumigation, besides destroying the population present in the grain, can also influence the composition of storage fungal species (Sinha, et a1. 1970) that reestablish in the grain once the fumigant has dissipated. Physical disturbance of the grain when it is handled can cause, in extreme cases, mortality by the physical destruction of the insects (Loschiavo 1978) and in less extreme cases, behavioral changes in the insects (Browning 1947). The ecology of stored-grain insects in the bulk grain subecosystem is truly complex and dynamic. Consider, for example, wheat that is harvested in North Dakota and possibly stored there for a short time, then transported to a terminal port elevator in New Orleans where again it may be stored until it is loaded on a ship which may pass through several climate zones before the grain is actually unloaded in a foreign port. Insect populations have been shown to be influenced by the action and interactions of the structural, 24 biotic, and management components which continually impinge upon them. Residual POpulation Ecology Many of the factors that influence grain mass popula- tions undoubtedly also influence residue populations. As previdusly mentioned, the residual subecosystem is radically different, being much more permanent and stationary. Usually, smaller amounts of grain material and grain material of a different composition and condition are present in the re- sidual system. The grain mass system is nearly always com- prised of a pure stand of one particular type of grain with a low percentage of grain particulate, while residual material consists of different types of grain and grain material that have accumulated through time in a particular location within the structural component. Density-dependent factors that influence insect populations are probably more perceptible in the residual system because of the amount, condition and permanence of the material (Solomon 1953). There is very little literature on the factors that specifically influence residual populations. The previous work that is available is primarily that of detection surveys of insects found in residual material located in and around storage, transportational, and processing facilities. These surveys are the topic of the following section. 25 Sources of Infestation Natural Sources Stored-grain insects, as a group, have evolved the abil- ity to persist in the man-made environment of the post har- vest grain ecosystem. These insects, however, are widely distributed in nature as well. These natural sources of in- festation should be an important consideration in stored- grain pest management. Linsley (1944) provides a detailed account of the natural habitats and reservoirs of many insect species associated with grain. These insects are broadly classified, according to habitat, by Linsley, as follows: seed-infesting species; fungus-feeding species; scavengers of dead plant material; scavengers of dead animal material; scavengers and predators living under bark; wood borers and wood scavengers; scaven- gers and predators living in the nests of insects and other animals; predators and parasites. Naturally, some species can belong to two or more categories. Only those species anticipated to be encountered during the present study will, be discussed. The following is taken entirely from Linsley (1949). Of the many species that infest seeds under natural conditions, only a few will attack stored seeds. Such behav- ior involves little change in food habits and probably little adjustment to the new environment, although some change in tolerance of relative humidity and moisture content of the 26 food was probably required in many cases. Among the few in- volved in this category are some serious pests. These in- clude: Sitophilus spp.; the bean weevil, Acanthoscelides obtectus (Say) (ColeopterazBruchidae); and two moth species, the Angoumois grain moth and the European grain moth, Nemopggon granella (L.) (Lepidoptera: Tineidae). Numerous species which occur in stored food are primarily fungus feeders. They are most commonly found in old, damp products and probably confine their feeding to the fungi and molds present. Included in this group are: the grain mites of the genus Acarus; the foreign grain beetle, Adasverus advena (Waltl) (Coleoptera: Cucujidae); and the meal moth, Pygalis farinalis (L.) (Lepidoptera: Pyralidae). Insect scavengers of plant materials provide an obvious source for stored-product pests. This group includes: the Blattiodea; Psoc0ptera; the Indian meal moth; and the Mediter- ranean flour moth, Anagasta kuhniella (Zeller) (Lepidoptera: Pyralidae). Of the species belonging to the animal scavenger group, only members of the Family Dermestidae, including Trogoderma, Anthrenus, and Attagenus, are important. Many pests of stored products appear to have originated as species that live under tree bark, the majority coming from tropical and subtropical regions. The bark habitat, besides offering protection and favorable physical conditions, provides varied foods of both animal and plant origin. Of the insects occupying this habit, the majority are plant scavengers, many are fungus feeders, some feed on both living and dead insects, 27 and a few are strictly predaceous as larvae and adults. The bark group includes: the Cadelle beetle; Tribolium spp.; Cryptolestes; the sawtoothed grain beetle; the foreign grain beetle; the larger black flour beetle, Cynaeus angustus (LeConte) (Coleoptera: Tenebrionidae); the spider beetle (Ptinidae); and the Mediterranean flour moth. 9. an ustus is also found at the bases of Yucca plants in Arizona. A few of the species associated with stored-grain orig- inated from.wood boring types. Most of these retain their boring characteristics and attack whole grains or processed food of a compact nature. This group includes: Ptinidae spp.; the drugstore beetle, Stegobium paniceum (L.) (Coleoptera: Anobiidae); and the lesser grain borer, Rhygopertha dominica (Fabricius) (Coleoptera: Bostrichidae). The ptinids and anobiids also infest loosely ground material. The nests of bees, wasps, ants and certain other insects and animals present an attractive environment for many insects. This habitat offers protection, favorable temperature and humidity, and usually stored food material (pollen, seeds, feathers, fur, dead insects). Social bees and wasps provide more favorable conditions for stored grain insects because these species use their nesting sites longer and store more food than do solitary species. Members of this category include: the black carpet beetle, Attagenus megatoma, which is also found in bird and chipmunk nests; Tribolium; mealworms, Tenebrio spp.; Ptinidae; Cryptolestes; Indian meal moth, which has actually been recorded as a pest of bee hives; the 28 Mediterranean flour moth; the sawtoothed grain beetle; drug- store beetle; and even the granary weevil in ground squirrel nests. Among the hundreds of parasites and predators listed by Good and Cotton (1937) to be associated with stored products, it is not known which are attracted to their hosts by the food materials and by the environment in which these are stored. Linsley suggested that the windowpane fly, Sgggg- pinus fenestralis (L.) (Diptera: Scenopinidae), is attracted by the habitat. Field Infestation and Insect Migration Grain or grain products can become infested with storage insects at any point from the time the grain ripens in the field to the grain product sitting in the kitchen cupboard. Cotton, 23 a1. (1953) reported wheat ripening in the field in southern Kansas, Illinois, Indiana, and Missouri to be occasionally attacked by the rice weevil, but found no evidence of this occurring further north. Chao, g3 31, examined 451 samples collected from trucks delivering wheat” directly from the field in Washington and found stored-grain insects in 13 of these samples, including two granary weevils. In further studies, involving sweeping of ripened fields with nets, these workers found no stored-grain insects and sugges- ted those insects found in the samples collected from trucks to have originated from the equipment used to harvest the grain. This notion is supported by the presence of the gran- ary weevil in samples taken from the trucks because this 29 pest is unable to infest standing wheat (Cotton 1963). Schwitzgebel and Walkden (1944) reported migrating in- sects constituted an important source of infestation of stored grain. Using several types of flight traps located in and around a large storage complex, these authors re- corded several species of storage insects including 9512' tolestes, red flour beetle, rice weevil, sawtoothed grain beetle, and Indian meal moth to be actively flying in the vicinity of the storage complex. Whether or not these in- sects were truly migratory or merely the ambient population of the storage complex was not adequately demonstrated. On-farm Sources of Infestation Liscombe and Watters (1962) collected samples of grain residue from.30 wooden farm granaries in the Canadian Prairie Provinces. These samples were collected from wall and floor cracks, top and bottom plates of the walls, floor sweepings and the ground. Over 50 species of insects and mites representing 38 families and 7 orders were collected from these samples. Ground samples were not heavily infested although the authors reported no significant differences among locations within the granaries. Sinha (1974) studied the seasonal abundance of insects and mites in 4 farm granaries in Manitoba, Canada. He reported two insect species; Cryptolestes ferrugineus and a psocid; and two mite species to be present in these gran- aries every month from May to December. Populations of Q. 30 ferrugineus began to increase in early May, peak between July and September, and crash during December. This in- sect was found every year in these granaries during the three year study period. Sources of Infestation in Elevators and Feed Mills . Chao (1954) collected samples from empty grain bins in 3 elevators in Washington. From these samples, nearly 10,000 insects were collected of which 40% were granary weevils, 26% were Cryptolestes, 22% were sawtoothed grain beetles, and 11% were red flour beetles. Also found were: yellow meal worms, Tenebrio molitor; black carpet beetles, Attagenus megatoma; meal moths, Pyralis farinalis; European grain moths, Nemopogon granella; Cadelle beetles; Tenebroides mauratanicus. Coombs and Freeman (1955) investigated some possible factors affecting the distribution of insects in the resid- ual material of a retired commercial granary in England. Samples were collected from wall cavities, the grain dis- tributing system and other accessible sites. Samples were also categorized as to the level or story from which they were collected and by the condition of the grain material. 'Condition' reflected the relative proportions of whole kernels, ground grain, dust and grit. Wall samples were further categorized by the directional orientation of the wall from which they were collected. In general, insects were more abundant on the ground floor than on the upper levels. Samples collected from north and south walls were, 31 in general, more heavily infested than those collected from east and west facing walls. Insects were also more abundant in samples containing a high proportion of whole grains and their numbers decreased as the proportion of whole kernels decreased. Rilett and Weigel (1956) studied insect populations in New York feed and flour mills during the winter months.‘ Samples were collected from any site thought to harbor in- sects. From 27 pounds of residual material collected from 11 feed and flour mills, 23 species of insects were found surviving New York State winters. The black carpet beetle and sawtoothed grain beetle were the most commonly found, being present in 8 of the 11 establishments sampled. Cryptolestes was present in 7, the Cadelle beetle in 6, the confused flour beetle in 5, and the granary weevil was present in 4 of the 11 establishments sampled. Triplehorne (1965) conducted an extensive survey of insects occurring in Ohio grain elevators and feed mills. This survey included 118 randomly selected facilities. Samples were collected, both in the spring and fall, from any site thought to harbor insects. A total of 44 species, representing 21 families in 5 orders of insects were re- covered from the samples. There was little correlation in numbers and species of insects between spring and fall samples collected from the same location. No distributional pattern for any species was evident. All species that were abundantly present in numerous locations within the facil- 32 ities were also widely distributed over the state. Loschiavo (1975) compared the occurrence of insects in several types of grain storage facilities. Samples were collected from on-farm storage sites including permanent buildings, temporary cribs, open piles of grain covered with plastic sheeting and from grain residues in commercial elevators. None of the samples from.permanent farm buildings were infested, but more than 27% of the samples collected from residues in commercial elevators were infested with either Cryptolestes ferrugineus or fungus beetles or both. Other Sources and Surveys On-farm and commercial storage and processing facilities have been shown by the above authors to contribute signifi- cantly to the probability of grain becoming infested as it is stored or processed in these facilities. However, there is a distinct possibility that grain will become infested as it is transported by rail in boxcars during any month of the year (Cogburn 1973b). After examining the boxcars delivering cargoes to Gulf ports, Cogburn reported 74% contained enough residual material from previous loads to support insect populations. Samples of residual material showed that 81% of those boxcars able to suStain populations actually contained insects. 0f the species collected, the flour beetle, Trogoderma, Cryptolestes and the lesser grain borer were the most common. Cogburn suggested that the nature of boxcar construction, which hinders sanitation, and the general sanitation practices were largely responsible 33 for insect populations in boxcars. Cogburn (1973a) in earlier studies found Gulf port warehouses to be another important source of insect infes- tation in export goods. The peak insect abundance in these warehouses occurred in August and September and some species were present throughout the year. The most common sources of infestation were damaged or spilled commodities, espec- ially in pallets, that remained in the warehouses for long periods of time. Other geographical surveys of stored-grain insects include: Zuk (1958) in British Columbia; Strong (1970) in California; Loschiavo and Okumura (1979) in Hawaii. Zuk (1958) conducted a large scale detection survey of grain elevators, cereal warehouses, and flour mills in British Columbia. From 40 to 108 such firms were sampled each year during the 7 year study period. A total of 53 species of insects, including many common storage pests, were recorded. The most widespread species were: the Australian spider beetle, Ptinus ocellus Brown (Coleoptera: Ptinidae); the black carpet beetle; the Mediterranean flour moth; the granary weevil; and yellow mealworm, Tenebrio molitor. Zuk also noted that many species were observed year after year in the same establishments. Most surveys of stored-grain insects have been conducted in close proximity to grain facilities. Strong (1971) surveyed nonstorage facilities for storage insects using a sheltered food packet trap to obtain the samples. Over 50 34 species of storage insects were collected from nonstorage facilities such as carports, garages, equipment sheds, inactive poultry sheds and cattle barns. Loschiavo and Okumura (1979) conducted an extensive survey of storage insects in Hawaii. In this study, flight traps were placed along side of feed mills, two miles from a feed mill, and in areas distant to feed mills. Food-baited traps were also placed in feed stores, food warehouses, and supermarket storage areas. Samples of grain residue were also collected from these premises and others, such as riding stables and livestock ranches. Over 60 species of stored-product insects were recorded during this survey. Every feed mill, feed store, food warehouse, supermarket, riding stable, and livestock ranch was infested with one or more species. The largest number of species and quantities of insects were collected in or near feedmills. The authors also conducted a small mail survey of residences and reported the most common species found on the other premises were also present in homes. The accounts presented by the above authors demonstrate dramatically the overwhelming pervasiveness of storage in- sects in the post harvest grain ecosystem. Outbreaks of insects in stored-grain must be viewed not as single, spontaneous, or arbituary events, but rather as results of the interactions among the grain, insects, microorganisms, and the various storage, transportational, processing, and marketing components. METHODS AND MATERIALS Preliminary Study Country elevators provide many services for cash-crop farmers and livestock producers. These facilities, upon receiving grain or beans from.growers, clean, dry and store the grain and, if desired, many are capable of preparing livestock feeds. Grain and beans that are sold to the elevator are stored until the market warrants their further movement. Because of the different services provided, the grain is constantly moved or redistributed within the eleva- tor to those locations where it is dried, cleaned, processed and finally stored or loaded on trucks or railcars. Resid- ual material accumulates in any site where spills occur and are not prOperly cleaned up. No two country elevators are identical in construction or in the organization of the various machines or structures used to process the grain; however, many simularities do occur. A preliminary study was conducted on March 20, 1978 in a nearby country elevator in order to develOp efficient sample collection, coding and evaluation methods to be used in the large scale study. When this study was first con- ceived, the objectives were to identify the storage insect species commonly found in residual material and to describe 35 36 those sites in and around the elevators that frequently harbor insects. No attempt was made at that point to inves- tigate the possible factors influencing the distribution or density of storage insects in these sites. It was not until the preliminary samples were evaluated that further investigation of these possible factors seemed warranted. Nearly every sample collected during the preliminary study contained insects. The extent to which these samples were infested, and the variety and abundance of insect species were totally unexpected. Based on observations in the preliminary study, the large-scale study was expanded in scope to include investigation of the possible environ- mental and biological factors affecting the distribution and density of storage insects in the country elevator eco- system. Large Scale Study Areas of the State and Elevators Sampled There are approximately 380 off-farm storage facilities operating in the state of Michigan, most of which are loca- ted in the southern half of the Lower Peninsula where the .majority of the grain and beans are produced (Stanley, £5 a1. (1979). Six areas within this major production belt were selected for this study. Three elevators from each area were sampled, except one in which an elevator exploded 3 days before it was to be sampled. 37 Permission to sample was solicited by county Coopera- tive Extension Service agents from elevator managers in their respective counties. After notification of those who agreed, each manager was contacted by mail and given a brief description of the study, assurances of confidential- ity and thanks for cooperating. One week before an elevator was sampled, the manager was contacted by phone to confirm the day and time samples could be collected. Each manager was interviewed just prior to sample collection and information on the elevator's capacity, grain and beans handled, sanitation policies, past insect problems and control practices, and other pertinent informa- tion was obtained. Completed interview sheets from.each manager are presented in Appendix A. Each area and elevator sampled was assigned a code number. Elevators will only be referred to by this code number. The area code, area, and elevators (by code) sampled within that area are as follows: Area Code Area - Elevator Code 1 Northern 10, ll, 12 2 Northeastern 2, 3, 4 3 Central 7, 8, 9 4 Southeastern l6, 17, 18 5 Southern 5, 6 6 Western 13, 14, 15 38 Parameter and Parameter Category Selection The preliminary study provided needed insights into the complex nature of residual insect populations in the elevator ecosystem. Observations made during the prelimin- ary study suggested several possible sources of variation that could affect the distribution and density of residual insect populations. These possible sources of variation are termed, for the lack of a better word, 'parameters,‘ and factors within a parameter are termed 'categories.' It was hypothesized that these parameters reflect differences in the physical environment of residual insect populations and thereby influence these populations. The parameters are as follows: Inside or Outside Samples were categorized by whether they were collected from inside or outside the elevators. Residual material sheltered and protected from the weather would seem to pro- vide a better environment for insects than material that is exposed to extreme weather conditions. Wet grain material quickly decomposes and soon becomes unfit for most stored grain pests, excluding fungivores. This parameter was coded and categorized as follows: Code Definition 1 Inside: From residual material contained within the walls of the elevator structures 2 Outside: From residual material not con- tained within the walls of the elevator structures 39 Level Combs and Freeman (1955) classified samples of residual material according to the level or story of the elevator from.which the sample was collected, and observed differences in the abundance of insects among the levels. Therefore, level was included as a parameter and coded and categorized as follows: Code 1 Definition 0 . From residual material located in the basement or below ground level 1 From.material located on the first or ground floor; or from the ground 2 From material located on second level 3 From material located on the third level 4 From material located on the fourth level It must be noted here that the upper levels (codes 2, 3, or 4) did not always represent a complete story, many times these denote small platforms or landings along a stairway or manlift route. Site Included with every sample was a brief description of the exact site from which the sample was collected. After all the samples had been collected, each sample was grouped into one of 58 categories based on key words in the site description. The particular site may influence insect popu- lations by the type and condition of material that accumu- lates at that site, the rate that it accumulates there, and 40 by length of time that material remains undisturbed in that site. Sites are coded and categorized as follows: Code Outside Sites 1 2 10 ll 12 Inside sites l3 14 15 16 17 18 Definition Along railroad tracks Screenings dump where grain debris is piled before it is disposed of Beneath buildings In and around the grain dryer Under boardwalks or elevated walk- ways along the outside walls .Cob storage area Along the bases of outside walls Along the bases of grain storage, storage silos or metal bins Truck loading docks Ground piles of spilled grain Dump pit areas where grain is first received into the elevators Large truck scales Wall cavities Tunnel or crawlspace that provides access to some below ground structure or machinery Inside grain wagons Under floor ramps Under large truck hoists Old bags of grain or grain material 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 41 Other containers such as pails, bushel baskets, or garbage cans Inside small carts or trolleys used to move small amounts of material inside the elevator Hoppers into which grain or feeds are dumped before processing Small buildings that house grain distribution machinery Electronic eye room.where navy beans are sorted Cleaning mills where grain debris or screenings are removed from the grain Grain scales Miscellaneous grain machinery Leg boots which are at the bases of vertical belt conveyors that transport the grain upwards Bin selectors which are flattened, circular dials about 2.5 feet in diameter that are suspended above the floor Along horizontal grain conveyors Livestock feed grinders Livestock feed mixer and bagger Floor sample from a flat storage area Floor sample from selector used extraneous rooms General floor sample taken from a room with the aid of bench brush Spills and piles of grain on the floor Around storage pallets 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 42 Leg pit, which is a well or pit containing a leg boot On stairways Window ledges Head house which is located on top of large concrete grain silos that house grain distribution maChinery Under stairways Suspended platforms or catwalks that provide access to structures and machinery in extreme upper levels of the elevator At the base of manlift routes, a manlift is a small elevator in which 1 or 2 people can ride Inside manlifts Beams, planks, or ledges Small storage bins Behind sliding doors Bases of grain silos Board walks or elevated walkways Along bases of inside walls Around molasses tanks, molasses is used in preparing livestock feeds Dump pit where grain is first received into the elevator In and around grain dryer Feed bagging area Cob storage area Bagged screenings storage area Truck loading docks Other sites 43 Structure Samples were also categorized by structural material used in the construction of the particular site from.which the samples were collected. Structure may influence insect population in that some species, such as the cadelle beetle, burrow into wood to overwinter or pupate. Structure may influence the sanitation and moisture content of material at a particular site. Different structural types are coded and categorized as follows: Eggs Definition 1 Material collected from the ground 2 Site constructed of stone or concrete 3 . Site constructed of wood 4 Site being mechanical in nature 5 Site constructed of some other material such as steel Structural types can also be a composite of two or more types. Sites such as the bases of wooden walls on a con- crete floor are coded as 23 for example, and the bases of machinery on a wooden floor are coded as 34. Amount of material The amount of residual material present at the site when the sample was collected was also noted. This par- ameter varied tremendously among sites. In some sites, such as general floor samples, the material had to be swept up from a large floor space in order to get enough material. 44 Other sites, such as beneath buildings where grain material accumulates for many years and is never cleaned up, may have had several hundred bushels of material present. Differences in the amount of material present are coded and categorized O as follows: 02d; Definition 1 Less than 1 quart present 2 . Between 1 quart and 1 bushel present 3 Between 1 bushel and 3 bushels present 4 Greater than 3 bushels present Moisture content It was apparent from.the preliminary study that, in many cases, sample collection was going to involve much climb- ing, twisting and crawling to obtain samples from bizarre elusive sites. Therefore, bulky equipment to measure temp- erature and moisture of the grain present at the site was sacrificed for quickness and agility. The elevators were to be in Operation at the time of sampling and the author did not want to interfere. No measure of grain temperature was taken and only two levels of moisture are considered in this study. Moisture content is coded and categorized as follows: Code Definition 1 Dry; material that easily poured into the sample container 2 Moist; material that had a sticky, clumpy quality. 45 Although no measure of moisture was precisely taken, nearly all samples coded as dry contained very little moldy material. Since molds and fungi do not develop well on grain material that is below 15% in moisture content, dry coded material was probably below that moisture level. Moist coded material was invariably well endowed with fungi and molds when samples were evaluated. Because of amount of literature on the effects temperature and moisture have on stored insects, the author felt nothing new could be added. Predominant Grains or Beans Present The type of grain was shown by LeCato (1975a) to sig- nificantly affect the number of progeny produced by several species of storage insects. Therefore, the type of grain and beans present in the residual material were considered as a possible physical and/or biological factor influencing insect populations. The type of grains or beans present as whole seeds in the sample are coded and categorized as followes: 99g; Definition 0 No or very little whole grain and beans present 1 Corn predominantly present 2 Wheat predominantly present 3 Oats predominantly present 4 Rye predominantly present 5 Barley predominantly present 6 Dry beans predominantly present 46 7 Soybeans predominantly present 8 Other As with structure categories, combinations of predominant grain and beans were coded by combining the single digit codes of those grains or beans present. Residues contain- ing corn, wheat, oats are coded 123. Condition of the Grain Material Coombs and Freeman (1955) reported the condition or re- lative composition of the grain residue affects the abundance of storage insects found in these residues. Coombs (1962) quantified residue condition by the volume weight ratio of the material, but found no advantage of this method over sub- jectively classifying the residue by visual inspection. Con- dition categories used in the present study were adopted from those used by Coombs and Freeman (1962), but were expan- ded to include a wider range of conditions. The conditions of the grain were coded and categorized as follows: Code Definition 1 Residues containing a high proportion (ca. 90%) of whole-seed grain or beans 2 Residues containing a moderate pro- portion of whole-seed grain or beans with the remainder comprised of cracked or ground seeds, dust, and chaff 3 Residues containing very little whole-seed grain and beans, compris- ed mainly of cracked or ground seeds, dust and chaff 47 4 Residues containing very little cracked or ground seeds, comprised mainly of dust and chaff 5 Residues comprised primarily of chaff 6 Residues comprised primarily of dust 7 Residues containing wet, weathered and moldy material 8 . Residues containing a high proport- ion of feed pellets Data Collection Sample collection Each elevator was sampled only once during the large scale study. Those elevators located within the same area were sampled in the same week to minimize travel costs, as two elevators could be sampled in one day. The order in which the elevators were sampled depended largely on when the elevator managers would agree on the date their elevator was to be sampled. Elevators were sampled beginning on July 6, 1978, and three per week until August 9, 1978. The dates the individual elevators were sampled are as follows: Eggs Elevator Sampled July 6, 1978 3 7 2, 4 12 5 l3 6 20 7, 8 21 9 26 ' 10, 11 27 12 August 1 13 2 14, 15 8 16, 17 9 l8 Quart-sized samples of residue grain material were collected from nearly every accessible site in and around the various buildings that make up an elevator. Very often, an elevator would consist of not just one building, but of a complex of buildings, each having specific functions. Each building in the complex was systematically searched end to end and t0p to bottom for any accumulation of residual material. When residual material was found, approximately one quart of the material was placed, with the aid of small flour scoop and bench brush, into a quart-size plastic ZIP- LOCKr bag which was then sealed. If large amounts of material were present, scoops of material were taken from several locations in the material. In many cases, the sample con- tained a large proportion, if not all, of the material present at the site. Each sample was labeled by including duaelevator code number and a sample number. Sample numbers were consecutively assigned, starting at one for each eleva- tor, as the samples were collected. A sample label 05-03, identifies the third sample collected from elevator 5. As each sample was collected the following parameters were carefully noted and coded: whether it was from inside or outside the elevator; the level from which it was 49 collected; the structure; the amount of material present; and moisture content of the material. These parameter codes, the sample label and a brief description of the site were recorded on specially prepared data sheets. Sample Incubation Samples were brought to the laboratory and incubated to allow immature stages of insects to complete their develop- ment. Samples were incubated under ambient room temperature and relative humidity since incubation chambers large enough to contain all the samples were unavailable. Plastic l6-oz. squat containers with clear plastic lids, similar to cottage cheese cartons, were used to incubate the samples. The lids were modified to facilitate gas exchange by removing a 2 in. equilateral triangular section from the center of the lid and cementing 64 mesh nylon screen over the opening. These containers were labeled exactly as the plastic bags from which the sample material was transferred. The filled containers were then stacked on ant-proofed platforms with sheets of 0.25 in. hardware cloth placed between the stacked tiers of containers. The hardware cloth provided needed support and air circulation throughout the stacks. Samples were incubated for an average of 661 .7 days. The incuba- tion period varied among samples because of the manner in which they were evaluated. 50 Sample Evaluation Samples were evaluated in the same order as they were collected. Those samples collected the first week were the first to be evaluated. It was hoped that all samples collec- ted during a particular week could be evaluated in one week, thereby standardizing the incubation period. Because of the time required to evaluate the samples this schedule was not exactly kept and the incubation period varied. The number of days the samples were incubated was recorded when the samples were evaluated and this variable was considered as a possible source of extraneous variation and analyzed as such. Before insects were collected, the weight of each sample was recorded to the nearest gram. The weight of the sample, like days of incubation, was considered as an extraneous source of variation and analyzed as such. After the sample was weighed, the live insects present were retrieved by shifting the material through consecutively smaller sieves and collecting the live insects with either an aspirator or forceps. Multivoltine (two or more gener- _ ations per year) species were collected as live adults and placed in 70% alcohol until they could be identified and counted. The condition of the material and the predominant grain and beans present were determined after the material had been shifted through the sieves. The whole-seed grains and beans were usually contained in the first two sieve fractions and could be easily identified. The relative composition or 51 condition of the residual material was determined by visual inspection of the relative proportion of whole grain, ground grain, dust and chaff present in different sieve fractions. The data file All data recorded for each sample are stored on a permanent computer tape and on data cards which are avail- able upon request from Dr. R. F. Ruppel, Department of Entomology, Michigan State University. The raw data are also presented in Appendix B. All data recorded from a sample are included on a single record or line in this perm- anent file. The variables, in the order they were entered on a record from left to right are as follows: Mnemonic name Variable AREA Area of the state, by code, from which the sample was collected DSAM Julian date sample was collected ELEV Elevator, by code, from.which sample was collected LCAP LOG, base 10, transformation of the maximum capacity of eleva- tor, in bushels SNUM Individual sample number INOT Parameter code from inside or outside collected samples LEVL Level, by code, from.which sample was collected Site Site, by code, from.which sample was collected STRT Structure, by code, of site from.which the sample was collected AMNT MOIS PGPS COND WSAM DINC GRWV CRYP RDFB CNFB SWTH DKMW BKCB CADL LBFB DGSB PTND 52 Amount of material, by code, present at site from which the sample was collected Moisture content, by code, of the residual material Predominant grains or beans present in sample, by code Condition, by code, of the residual material in sample Weight of the sample, in grams Days sample was incubated Number of granary weevil adults collected from sample Number Number adults Number adults Number beetle of ngptolestes adults of red flour beetle collected from sample of confused flour beetle collected from sample of sawtoothed grain adults collected from sample Number larvae Number of yellow mealworm collected from sample of dark mealworm.larva collected from sample Number larvae Number adults Number beetle sample Number adults Number of black carpet beetle collected from sample of cadelle beetle collected from.sample of larger black flour adults collected from of drugstore beetle collected from sample of ptinid beetle adults collected from sample 53 MDFM Number of Mediterranean flour moth adults collected from sample MITE Code for presence or absence of mites in sample, 1 if present and 0 if absent SCNO Number of windowpane fly larvae present in sample The FORTRAN format of these variable is: (11, 1X, 13, IX, 3(12, 1X), 2(Il, 1X),2(12, IX), 2(Il 1X); 13, 1X, I1, 1X, 2(13, 1X), 3(14, 1X; 13, 1X), 12, 1X, 14, 1X, 4(12, 1X). Analyses Once the data were entered into the computer permanent file, several types of analysis were performed to demonstrate and statistically verify the physical and biological factors influencing residual insect populations in the elevator. ecosystem. Fourteen species or species complexes were con- sidered, of which 7 were analyzed in detail. Insect density, in this study, is defined as the number of insects per gram of material as suggested by Solomon (1953). This transforma- tion is similar to ratio estimates described by Cochran V (1977) and helped to standardize the observed insect density in the samples in which the weight varied. The species that were analyzed in detail were the most abundant and most commonly found insects in samples. These species include the granary weevil (GRWV), Cryptolestes (CRYP), red flour beetle (RDFB), confused flour beetle (CNFB), sawtoothed grain beetle (SWTH), yellow mealworm (YWMW) and the black carpet beetle (BKCB). 54 Parameter categories stratified (Cochran 1976) the sample population of residual grain material by several en- vironmental criteria or parameters, (e.g., level, site, grain) that are somewhat unique to residual material in county elevators. For each area of the state, elevator and param- eter category in which 10 or more observations were made, the mean density and relative frequency of the above species were calculated and are presented in tabular form. Frequencies and mean densities given for level, site, structure, amount, moisture content, type of grain and condition categories represent inside collected samples only. The mean density and relative frequency presented for the parameter categories were calculated by collapsing the observations over all the other parameters. That is, each parameter was evaluated independently of the other param- eters. Interactions among parameters were not considered because of the number of observations needed to do so. To test whether or not elevators and parameter categories significantly affected the distribution and observed density of residual insect populations, a separate one-way analysis of variance was performed on the 7 common species with eleva- tor and parameters as the independent variables. The observed densities were transformed (Napieran log (density + 1)) to stabilize the variance in each analysis. The results of 63 (7 species X 9 parameters) analyses of variance are summarized and presented in tabular form. 55 The intent of the one-way analysis is not to declare significant differences among category means as described by Steel and Torrie (1960), but rather to test whether or not the criterion or parameter used to stratify the observations differed significantly from that of a completely random criterion. The effect of other species present in the sample on the density of 7 common species was analyzed by multiple regress- ion techniques described by Draper and Smith (1975). Mul- tiple regression is a method used to associate variability of a continuous dependent variable with the variability of several other continuous independent variables simultaneously. Although multiple regression is most often used to develop predictive models, it was useful in this study because it determines the percent of variability of the dependent variable that is associated with variability in the indepen- dent variables included in the equation. Also, as part of the output generated by SPSS (Statistical Package for Social Science) multiple regression analysis, correlation coefficients are given for all variables included in the analysis. Correlation coefficients measure the strength of the associa- tion between two variables, and significant correlation coefficients are present for all species included in the data file. Each of the 7 common species was considered the dependent variable in a separate multiple regression runs with the density of all other species plus the Julian date the sample was collected (DSAM), the log, base 10, of the 56 capacity of the elevator (LCAP), the weight of the sample (WSAM) and days in incubation (DINC) were included as the independent variables. LCAP was included to determine if the size of the elevator was associated with insect density. Sampling variables (DSAM, WSAM, DINC) were included to measure the effect of these on the observed insect density. Observed densities were transformed as in the one-way analysis of parameter categories. For the other 8 species included in the data file, only the frequency they were present in the data file, areas of the state, elevator and parameter categories were calculated. They were not presented in tables, and will only be discussed in the text. The density of these was not considered, as these species were present at very low levels. Generally samples contained more than one species, which suggested these species occur more often in a complex rather than in isolated homogenous populations. It was hypothe- sized that the same physical factors influencing individual species also influenced the number of species present. There- fore, the number of species present in a sample was also 1 considered as a dependent variable. The frequency of the number of species present in the samples are presented for each area, elevator and parameter category in tabular form in Appendix C. A separate one-way analysis of variance was performed with the number of species as the dependent variable and the elevators and parameter categories as the independent variables. 57 RESULTS General A total of 557 samples representing 165 kg (363 lbs) of residual grain material were collected from 17 operating elevators. Over 75% of the samples contained one or more species of stored grain insects or mites. The average sample contained 2.4 species. Storage species were collected from every site category in which 10 or more observations were made, regardless of the structure of site, the amount of material present and the moisture content, composition and condition of the residual material. The fourteen common storage species or species complexes collected furing the present study are presented in Table 1. Those species listed were present in at least 2 percent of the samples collected. The three most common species found, were the black carpet beetle, granary weevil and 9322- tolestes, which were very often found together in samples. Several other species less frequently collected were: the foreign grain beetle, Ahasverus advena (Waltl) (Coleop- tera: -Cucujidae); the larder beetle, Dermestes lardarius L. and Trogoderma sp. (Coleoptera: Dermestidae); other beetles belonging to Histeridae and Nitidulidae; meal moth, Pyralis 58 59 .muofisuouoocs .qu wuuflam oocHEpouooc: mcwumo< w.mH ham oomQBOocHS Amsmmcaqumwamuumocom mscwmocoom omowcwoozoom mHouQHn m.~ :uoE noon owocwnuouwpo: AHoHHoNvaHowanosx mummwmc< ompwamwxm ououaoowmoa . a maumon oHHoomo Amsmmccwgvmnowamuwusoe moowoucocofi omowufimowoue . moauoop powwow . woGflSuouoocn ooprHum . oauoon ououmwsuo AmsmoccHHNEamomcmm Ebmnowmm ompwwnon< . Hw>mo3 zuocmum AnnomccqumSHumcmu mm a mood omowcowHSUHDU . mauoon uoaumo xoman AHoH>HHOVmEoum we mono muu< mmpfiumofipmn 9 ONO‘HNNQWQHNW OHMWNMNMQ'NWN cur-4mm oHuooo :Hmuw voguoouBmm daemon know xoman Howuma ShoBHooE some Awoomcceqvmwmaoamcauom muscmomemo .am moumoaoummMo Amocooogvmsumswcm msomomm mowoanomh mansomeo owufioomk omownsoau . m Buozamoe 3oHHom mammacmu HouwHoE owunoCoP . H daemon Macaw ooh mumouomvEDocmummo EDHHommuH . a mauoon Macaw oomswcoo Annemacfiavaomsmcoo EDHHOAHHH ompflcowuoocme muouoooHoo at .ooum mama aoEEoo mam: vamwucoaom xafiEmm .moamamm Hoflumumfi ofimum Hmsowmou Houm>oao SH ocsow masoEEoo mowooam .H «Home 60 farinalis L. (Lepidoptera: Pyralidae); Indian meal moth, Plodia interpunctella (Hubner) (LepidOptera: Pyralidae); and the European grain moth, Nemapogon granella (L.) (Lepidoptera: Tineidae). Also collected were species be- longing to: Syrphidae, Muscidae, Mycetophagidae (Diptera): Anthocoridae and Rediviidae (Hemiptera); and hymenopterous parasite families of Pteromalidae and Bethyidae. Granary Weevil The granary weevil (GRWV) was present in 34.8% of all samples collected during the survey with an average density: of .1376 adults gm. and standard deviation of .788 GRWV gm. of sample material. The frequency and mean density of GRWV in each area, elevator and parameter categories in which 10 or more observations were made are presented in Table 2. The frequencies and mean densities presented for level, site, structure, amount of moisture, grains and condition cate- gories are for inside collected samples only. GRWV was found in every area of the state sampled and was present in 16 of the 17 elevators sampled. It was most” widespread in elevators 10, 12, 9 and 17 being present in 80%, 78%, 57% and 54% respectively, of the samples collected from these elevators. The elevators in which GRWV was most frequently found also had the highest observed mean density of GRWV. The elevators in which GRWV was least common also had the smallest mean densities and were all located in area 1. In general, the majority of samples in which GRWV was present contained densities of 0.2 or less GRWV adults/gm. 61 Table 2. Frequency and mean density of GRWV in the areas of the state, elevators and parameter categories. Criterion Category Code Relative Density N frequency (no./gm.) Area 1 .62 .3627 58 2 .02 .0076 93 3 .28 .0879 132 4 .32 .3466 110 5 .25 .0155 52 6 .30 .0392 112 Elevator 2 .03 .0014 37 3 .09 .0186 35 4 0.00 .0000 21 5 .26 .0124 27 6 .24 .0188 25 7 .34 .0946 56 8 .31 .0362 32 9 .57 .1170 44 10 .80 .6742 25 ll .13 .0014 15 12 .78 .2311 l8 13 .45 .0508 38 14 .34 .0371 35 15 .18 .0297 39 16 .43 .0596 42 17 .54 .8304 41 18 .41 .0586 27 In or out inside 1 .41 .1742 428 outside 2 .09 .0163 129 Level basement 1 .68 .2508 81 first 2 .38 .1296 245 second 3 .30 .3307 66 third 4 .45 .0270 22 fourth 5 .29 .0049 14 Site mills 24 .43 .0773 28 scales 25 .48 .2690 21 misc. machinery 26 .21 .0369 14 leg boots 27 .73 .3840 22 feed grinder 30 .77 .0885 13 general floor 34 .39 .1657 114 floor spills 35 .54 .0870 13 leg pits 37 .50 .3007 12 stairways 38 .50 .0381 10 platforms- catwalks 42 .43 .0274 21 Table 2 (cont'd.). Criterion Category Code Relative -Density N frequency (no./gm.) Site beams-planks- 1edges 45 .45 , .1178 11 small bins 46 .50 .0072 10 inside walls 50 .33 .0631 18 \dump pit area 52 .29 .0865 21 Structure concrete 2 .36 .0693 151 wood 3 .44 .2164 147 mechanical 4 .40 .4792 35 other 5 .36 .1994 ll conc.-mech. 24 .68 .1360 37 wood-mech. 34 .49 .1871 37 Amount less than 1 qt. 1 .26 .2573 43 1 qt.-l bu. 2 .35 .1783 175 l bu.-3 bu. 3 .52 .0947 122 greater than 3 bu. 4 .52 .2359 88 Moisture dry 1 .43 .1652 411 moist 2 .35 .0148 17 Grains no whole grain 0 .09 .0013 111 corn 1 .62 .1133 68 wheat 2 .59 1.1819 34 oats 3 .64 .0151 ll navy beans 6 0.00 0.0000 37 corn-wheat 12 .55 .2701 31 corn-oats 13 .78 .1136 32 wheat-oats 23 .85 .2025 13 corn-wheat-oats 123 .63 .0993 24 corn-wheat-soys 127 .82 .1559 11 Condition whole-seed grain l .55 .4838 62 whole grain- ground grain 2 .58 .2325 180 ground grain- dust-chaff 3 .36 .0251 87 dust-chaff 4 .09 .0057 57 chaff 5 .18 .0015 ll weathered-moldy 7 .08 .0004 13 feed pellets 8 .20 .0044 10 63 of material. Elevator 17 had 16% and elevator 10 had 12% of the samples with one or more GRWV adult per gram of material. The only elevator in which GRWV could not be found was elevator 4, and over 90% of the samples collected from elevators 2 and 3 did not contain GRWV. GRWV was much more frequent and abundant in samples collected from inside elevators than those collected from the outside. Nearly all samples that contained higher densities of GRWV were collected from inside the elevators and those samples collected from the outside that did contain higher densities were from locations that offered some protection from.the weather. GRWV was more commonly found in the basements of the elevators than in any other level and less frequently found in the fourth level. The highest observed GRWV density was from samples collected from the third and basement levels. Over 20% of the basement samples had observed densities of 0.2 or more GRWV adults/gm., while no samples collected from the fourth level contained GRWV at these densities. The specific sites inside the elevator that most fre- quently had GRWV present were, in decreasing order, feed grinders (30), leg boots (27) and floor spills (35). However, the largest mean density of GRWV was observed in samples collected from stairways (38), which had a mean density of over 1 GRWV adult/gm. of material. Higher mean densities were also observed in samples collected from leg boots (27) and leg pits (37) with over 0.3 GRWV gm. 64 Twenty-four percent of the samples collected from leg boots (27) contained 0.2 or more GRWV adults/gm. beams, planks and ledges (45) had 18%; feed grinders (30) had 16%; cleaning mills (24) had 12%; general floor samples (34) and dump pit areas (52) had 10% of the samples collected from these sites with 0.2 or more GRWV adults/gm. of material. The structure of the sites from which the samples were collected in which GRWV was most frequently found and most abundant were structural types involving some sort of mach- inery. Of the samples collected from sites of wooden and mechanical structure, 19% had 0.2 or more GRWV adults present gm. of material. The amount of residual material present at the site had little, if any, effect on the frequency and mean density of GRWV. The frequency of GRWV, in general, increased as the amount of material present increased but no consistent pattern developed for GRWV density. Although lesser amounts (codes 1,2) of material were less frequently infested, every category contained samples in which one or more GRWV adults/gm” were collected. ' GRWV was found nearly as often in moist coded (2) samples as in dry coded (l), but the mean density of dry samples was 10 times that of moist samples. Both moisture categories contained samples in.which GRWV density was greater than 0.2 adults/per gram but only dry coded samples contained extremely high GRWV densities. 65 Samples that contained little or no whole grain and those containing only navy beans differed dramatically, in both frequency and mean density of GRWV, from samples con- taining cereal grains. Samples containing primary wheat had the greatest mean density of any single cereal grain or grain combination. No sample containing only navy beans had GRWV present and samples containing very little or no whole grain had very low densities when GRWV was present. This should not be surprising as GRWV develops only in whole cereal grain of foods of a compact nature. As implied by the low frequency and mean density of GRWV in samples containing no whole grains, the condition of the grain material also significantly affected GRWV density. Mean density of GRWV decreased as the relative proportion of whole grain decreased. The maximum observed density of GRWV was 10.35 gm. of sample material. This sample was collected from a stairway inside elevator 10. There was less than 1 quart of mat- erial present on these stairs and the material consisted primarily of dry, whole wheat kernels. Presented in Table 3 are the results of multiple re- gression analysis of GRWV density observed in the samples. Variability in GRWV density is shown to be positively associated with the changes in cadelle beetle density (CADL) and the Julian date on which the samples were collected (DSAM). Even though both of these variables had significant slopes (b), the R2 shows that less than 6% of the variability of GRWV density can be associated with variability in CADL 66 Table 3. Results of multiple regression analysis of GRWV density. Variables in the equation Variable b Standard Partial F error of b significance CADL 22.7381 4.5455 .001 DSAM .0069 .0029 .017 constant -l.3197 Analysis of variance Source d£_' SS MS F Regression 2 19.5189 9.7595 l6.56** Residual 554 326.4023 .5892 Multiple r .2375 R2 .0564 67 and DSAM. Cryptolestes ngptolestes species (CRYP) were present in 25.7% of all samples collected with an average density of .0205 adult CRYP and standard deviation of .117 adult CRYP gm. of sample material. The frequency and mean density of CRYP in each area, elevator and parameter category in which 10 or more observations were made are presented in Table 4. Again, the frequencies and mean densities presented for level, structure, amount, moisture, grain and condition categories are for inside collected samples only. CRYP was found in every area of the state sampled and was present in 16 of 17 elevators sampled. It was most wide- spread in samples collected from elevators No. 12, with 50% of the samples infested with CRYP; 14, with 49%; 6, with 36%, and 8, with 34% of the samples infested with CRYP. As with GRWV, those elevators in which CRYP was most frequently found also had the highest mean densities of CRYP and the elevators in which CRYP was least common also had the smallest mean densities. Elevators located in area one (2,3,4) had the lowest frequency of infestation and lowest mean density of CRYP. CRYP was most common and abundant in samples collected from inside the elevators. Differences in both frequency and mean density are relatively small and the highest densities were recorded from samples collected from material inside the elevators. 68 Table 4. Frequency and mean density of CRYP in the areas of the state, elevators and parameter categories. Criterion Category Code Relative Density N frequency (no./gm.) Area 1 .38 .0219 58 2 .02 .0004 93 3 .28 .0145 132 4 .32 .0368 110 5 .25 .0501 52 6 .30 .0137 112 Elevator 2 .03 .0004 37 3 0.00 .0.0000 35 4 .05 .0009 21 5 .15 .0018 27 6 .36 .1023 25 7 .21 .0104 52 8 .34 .0093 32 9 .32 .0233 44 10 .28 .0090 25 ll .40 .0211 15 12 .50 .0403 18 13 .13 .0038 38 14 .49 .0210 35 15 .31 .0169 39 16 .33 .0774 42 17 .34 .0065 41 18 .26 .0198 27 In or out inside 1 .29 .0233 428 outside 2 .16 .0112 129 Level basement 1 .48 .0905 81 first 2 .24 .0085 245 second 3 .20 .0066 66 third 4 .41 .0024 22 fourth 5 .21 .0036 14 Site mills 24 .25 .0049 28 scales 25 .33 .0160 21 misc. machinery 26 .14 .0036 14 leg boots 27 .64 .1262 22 feed grinders 30 .54 .1602 13 eneral floor 34 .21 .0246 114 loor spills 35 .46 .0179 13 leg pits 37 .25 .0077 12 stairways 38 0.00 0.0000 10 platforms- catwalks 42 .57 .0060 21 Table 4 (cont'd.). Criterion Category Code Relative Density N frequency (no./gm.) Site beams-planks- ledges 45 .36 .0041 11 small bins 46 .10 .0003 10 inside walls 50 .22 .0116 18 dump pit area 52 .14 .0060 21 Structure concrete 2 .26 .0241 151 wood 3 .23 .0044 147 mechanical 4 .17 .0528 35 other 5 .36 .0028 11 conc.-mech. 24 .59 .0892 37 wood-mech. 34 .38 .0091 37 Amount less than 1 qt. 1 .12 .0018 43 l qt.-l bu. 2 .23 .0263 175 l bu.-3 bu. 3 .34 .0194 122 greater than 3 bu. 4 .42 .0331 88 Moisture dry 1 29 °0241 411 moist 2 .24 .0036 17 Grains no whole grain 0 .14 .0181 111 corn 1 .35 .0165 68 wheat 2 .41 .0142 34 oats 3 .27 .2095 ll navy beans 6 0.00 0.0000 37 corn-wheat 12 .39 .0101 31 corn-oats 13 .59 .0480 32 wheat-oats 23 .46 .0116 13 corn-wheat-oats 123 .46 .0738 24 corn-wheat-soys 127 .55 .0043 11 Condition whole-seed grain l .40 .0138 62 whole grain- ground grain 2 .37 .0295 180 ground grain- dust-chaff 3 .23 .0281 87 dust-chaff 4 .09 .0225 57 chaff 5 .09 .0007 11 weathered-moldy 7 .08 .0012 13 feed pellets 8 .10 .0006 10 70 Samples collected from.basements of the elevators were more frequently infested with CRYP than samples col- lected from any other level. Basement samples contained an average density 10 times that of any other level, and only basement samples contained densities of CRYP that exceeded 0.4 adult CRYP gm. of sample material. CRYP was recorded from samples collected at every in- side site except one (stairways) in which 10 or more observa- tions were made. CRYP was more frequently collected from leg boots (27), platforms or catwalks (42) and feed grinders (30). Highest mean densities of CRYP were recorded in samples col- lected from feed grinders and legboots. Densities of CRYP exceeded 1.0 adults/gm. in samples collected from these two sites as well as from general floor samples (34). Samples collected from sites involving machinery con- tained the highest mean densities of CRYP among the structural types. CRYP was found most frequently in samples collected from sites of concrete-mechanical nature. This structural category probably denotes accumulation of material around the bases of machinery in the basement level since basements invariably had concrete floors. Although most samples in which CRYP density exceeded 0.2 adults/gm. were recorded from sites of concrete and mechanical structure, high den- sities were also recorded from wooden structures. The frequency of CRYP increased as the amount of resid- ual material present at the site increased and the highest mean density was recorded from sites having greater than 3 71 bushels of material present. CRYP densities exceeding 0.4 adults per gram were recorded from sites in which the amount of material present was greater than 1 quart. CRYP was almost as frequent in moist coded samples as in dry coded samples collected inside the elevators, al- though the mean density of CRYP in dry coded samples was 7 times greater than that of moist coded samples. CRYP density exceeding 0.2 adults per gram was only recorded from dry coded samples. CRYP was more commonly found in samples containing whole cereal grain than samples containing no whole grains or samples containing primarily navy beans. Highest mean den- sities of CRYP were recorded from samples containing primar— ily oats or an oat-corn mixture. CRYP densities exceeding 0.2 adults/gm. were recorded from samples containing primarily corn, oats, corn-wheat, corn-oats, and corn-wheat-oats but also in samples containing no whole cereal grains. Samples containing primarily navy beans were completely void of CRYP. That CRYP prefers whole grains to loosely ground mater- ial for oviposition (Rilett 1949) is not reflected in its frequency and mean density in the condition of the grain categories. Although found more frequently in samples contain- ing primarily whole grains, highest CRYP mean densities were recorded from samples containing large proportions of ground grain. CRYP densities exceeding 0.2 adults/gm. were not recorded from samples consisting primarily of whole grains, but were recorded from samples containing ground grain and 72 even from samples consisting primarily of grain dust and chaff (4). The maximum CRYP density of 1.830 adults gm./was record— ed from a sample collected from a leg boot (27) in the base- ment of elevator 16. There was between 1 quart and 1 bushel of material present at this site and the material consisted primarily of dry oats and ground grain material. Presented in Table 5 are the results of multiple re- gression analysis on CRYP densities observed in the samples. Only one variable, confused flour beetle (CNFB) density, did show significant variability associated.with CRYP density. However, this association explained less than 2% of variabil- ity in CRYP density. CRYP density did not appear to be significantly associated with variability in sampling vari- ables, i.e., DSAM, WSAM, DINC. Red Flour Beetle The red flour beetle (RDFB) was present in 11.3% of all samples collected during the survey with average density of .0178 adults/gm. and a standard deviation of .191 adults/gm; The frequency of infestation and mean density of RDFB in each area of the state, elevator and parameter category in which 10 or more observations were made are presented in Table 6. Again, the frequencies and mean densities listed for level, site, structure, amount, moisture, grains and condition categories are for inside collected samples only. RDFB was found in every area of the state sampled and in 12 of the 17 elevators sampled. Elevators l3 and 14 had 73 Table 5. Results of multiple regression analysis of CRYP density. Variables in the equation Variable b Standard Partial F error of b significance CNFB .1851 .0733 .012 constant .0184 Analysis of variance Source df SS MS F Regression l .0867 .0867 6.39* Residual 555 7.5392 .0136 Multiple r .1067 R2 .0114 Table 6. Frequency and mean density of RDFB in the areas of the state, elevators and parameter categories. Criterion Category Code Relative Density N frequency (no./gm.) Area 1 .05 .0001 58 2 .01 .0134 93 3 .06 .0016 132 4 .05 .0010 110 5 .12 .0013 52 6 .36 .0737 112 Elevator 2 .03 .0337 37 3 0.00 .0000 35 4 0.00 .0000 21 5 .15 .0016 27 6 .08 .0010 25 7 0.00 .0000 52 8 .09 .0005 32 9 .11 .0045 44 10 0.00 .0000 25 ll .13 .0003 15 12 .06 .0002 l8 13 .55 .0312 38 14 .51 .2019 35 15 .03 .0001 39 16 .07 .0024 42 17 0.00 .0000 41 18 .07 .0003 27 In or out inside 1 .13 .0228 428 outside 2 .05 .0011 129 Level basement 1 .11 .0096 81 first 2 .11 .0267 245 second 3 .18 .0156 66 third 4 .36 .0076 22 fourth 5 .07 .0891 14 Site mills 24 .14 .0051 28 scales 25 .14 .0117 21 misc. machinery 26 .21 .0166 14 leg boots 27 .14 .0020 22 feed grinders 30 .23 .0210 13 general floor 34 .09 .0057 114 floor spills 35 .08 .0063 13 leg pits 37 .08 .0002 12 stairways 38 0.00 .0000 10 platforms- . catwalks 42 .33 0138 21 75 Table 6. (cont'd.). Criterion Category Code Relative Density N frequency (no./gm.) Site beams-planks- 1edges 45 0.00 0.0000 11 small bins 46 0.00 0.0000 10 inside walls 50 .11 .0051 18 .dump pit area 52 .24 .0040 21 Structure concrete 2 .12 .0153 151 wood 3 .12 .0095 147 mechanical 4 .11 .0052 35 other 5 .09 .0384 11 conc.-mech. 24 .27 .0229 37 wood-mech. 34 .16 .1244 37 Amount less than 1 qt. 1 .05 .0291 43 1 qt.-1 bu. 2 .13 .0114 175 1 bu.-3 bu. 3 .16 .0490 122 greater than 3 bu. 4 .15 .0059 88 Moisture dry 1 .14 .0237 411 moist 2 0.00 .0000 17 Grains no whole grain 0 .15 .0613 111 corn 1 .26 .0173 68 wheat 2 .03 .0024 34 oats 3 .09 .0083 11 navy beans 6 .03 .0001 37 corn-wheat 12 .16 .0047 31 corn-oats 13 .13 .0142 32 wheat-oats 23 531 .0026 13 corn-wheat-oats 123 .04 .0058 24 corn-wheat-soys 127 0.00 .0000 11 Condition whole-seed grain 1 .11 .0228 62 whole grain- ground grain 2 .14 .0025 180 ground grain- dust-chaff 3 .16 .0115 87 dust-chaff 4 .07 .0231 57 chaff 5 .18 .0164 ll weathered-moldy 7 0.00 .0000 13 feed pellets 8 .30 .0927 10 76 the most samples infested with RDFB and these elevators also contained the highest mean densities of RDFB. As with CRWV and CRYP, elevators located in area 1 had fewer samples infested with RDFB than any other area. Only eleva- tors 14, 13, and 2 yielded samples in which RDFB density exceeded 0.2 adults per gram. Elevator 14 had 18% of the samples containing RDFB densities exceeding 0.2/adults. gm. RDFB was twice as common and twice as abundant in samples collected from.inside the elevators as from outside collected samples; and only inside samples contained RDFB densities that exceeded 0.2 adults/gm. RDFB was more common in samples collected from the second and third levels inside the elevators than from the basement. The highest mean density, however, was recorded in samples collected from the first floor. RDFB densities ex- ceeding 0.2 adults/gm. were recorded from every level except the third. RDFB was recorded from 11 of the 14 inside site cate- gories in which 10 or more observations were made. It was more common and abundant in samples collected from elevated platforms and catwalks (42), feed grinders (30) and other miscellaneous machinery (26). Densities exceeding 0.2 RDFB adults/gm. were recorded from scales (25) and general floor samples (34). These densities were also recorded from several sites not listed in Table 6 including: containers such as pails and baskets; feed mixers (31); window ledges (39); under stairways (41); at the base of manlifts (43); and feed bagging areas (54). 77 Samples collected from sites involving machinery were infested more frequently with RDFB than other structural categories. The bases of machinery either on wooden or concrete floors yielded samples which were, on the average, more heavily infested with RDFB. Densities exceeding 0.2 RDFB adults/gm. were recorded from every structural category in which 10 or more observations were made. RDFB was more common in sites where larger amounts of residual material was present and had the highest mean den- sity recorded from sites in which there were 1 to 3 bushels of material present. Densities exceeding 0.2 RDFB adults/ gm. were recorded in every amount category except greater than 3 bushels present (4). RDFB was not found in any moist-coded samples collected from inside the elevators. RDFB was more common in samples in which corn or a mixture of wheat and oats were the pre- dominant whole-seed grains present. The highest mean density of RDFB was, however, recorded from samples containing little or no whole-seed grains. Densities exceeding 0.2 RDFB adults/gm. were recorded from samples in which corn and mix- tures of corn and oats were the predominant grains as well as samples with little or no whole-seed grains present. That RDFB is primarily a pest of processed foods is illustrated by the condition category in which RDFB was most common and had the highest mean density, namely, feed pellets (8). However, RDFB was recorded from every condition cate- gory except weathered and moldy material (7). Densities 78 exceeding 0.2 RDFB adults/gm. were recorded from condition categories 2,3,4, and 8. The maximum density of 4.195 RDFB adults/gm. was re- corded from a sample collected at the base of a feed mixer on the first floor of elevator 14. There were between 1 and 3 bushels of material present which contained no whole-seed grain or beans and consisted almost entirely of a dry ground grain-dust-chaff mixture. Multiple regression analysis of RDFB density failed to significantly associate variability of RDFB density with that of any other variable. Confused Flour Beetle The confused flour beetle (CNFB) was present in 10.9% of all samples collected during the survey with an average density of .0110 adults/gm. and a standard deviation of .067 adults/gm. of material- The frequency of infestation and mean density of CNFB in each area of the state, elevator and parameter category in which 10 or more observations were made are presented in Table 7. Again, the frequencies and ' mean densities listed for level, site, structure, amount, moisture, grains and condition categories are for inside- collected samples only. CNFB was not found in samples collected from any elevators located in area 1, but was found in 13 of the 14 remaining elevators. The highest mean densities of CNFB were recorded from samples collected from elevators 6, 8 and 79 Table 7. Frequency and mean density of CNFB in the areas of the state, elevators and parameter categories. Criterion Category Code Relative Density N frequency (no./gm.) Area 1 .19 .0040 58 2 0.00 0.0000 93 3 .13 .0280 132 4 .15 .0050 110 5 .10 .0140 52 6 .11 .0083 112 Elevator 2 0.00 0.0000 37 3 0.00 0.0000 35 4 0.00 0.0000 21 5 .07 .0007 27 6 .12 0284 25 7 .04 .0032 52 8 .16 .0271 32 9 .23 .0601 44 10 .28 .0088 25 11 0.00 0.0000 38 12 .22 .0007 18 13 .11 .0186 38 14 .17 .0022 35 15 .05 .0039 39 16 .14 .0100 42 17 .10 .0002 41 18 .22 .0047 27 In or out inside 1 13 .0128 428 outside 2 04 .0053 129 Level basement 1 .28 .0287 81 first 2 .10 .0096 245 second 3 .08 .0012 66 third 4 .05 .0001 22 fourth 5 .14 0496 14 Site mills 24 .14 0015 28 scales 25 .05 .0001 21 misc. machinery 26 0.00 0.0000 14 leg boots 27 .23 .0430 22 feed grinders 30 .46 .0370 13 general floor 34 .10 0084 114 floor spills 35 .31 .0248 13 leg pits 37 .25 .0497 12 stairways 38 .10 .0063 10 platforms- catwalks 42 10 .0138 21 Table 7. (cont'd.). Criterion Category Code Relative Density N frequency (no./gm.) Site beams-planks- ledges 45 .27 .0098 11 small bins 46 0.00 0.0000 10 inside walls 50 .11 .0008 18 dump pit area 52 .24 .0003 21 Structure concrete 2 .15 .0178 151 wood 3 .08 .0014 175 mechanical 4 .09 .0005 35 other 5 .18 .0014 ll conc.-mech. 24 .27 .0491 37 wood-mech. 34 .14 .0031 37 Amount less than 1 qt. 1 .07 .0176 43 l qt.-l bu. 2 .10 .0023 175 1 bu.-3 bu. 3 .11 .0023 122 greater than 3 bu. 4 .24 .0457 88 Moisture dry 1 .12 .0118 411 moist 2 29 .0361 17 Grains no whole grain 0 .06 .0090 111 corn 1 .18 .0128 68 wheat 2 .18 .0241 34 oats 3 .27 .0070 11 navy beans 6 .03 .0001 37 corn-wheat 12 .16 .0095 31 corn-oats 13 .28 .0276 32 wheat-oats 23 .15 .0008 13 corn-wheat-oats 123 .17 .0157 24 corn-wheat-soys 127 0.00 0.0000 11 Condition whole-seed grain l .13 .0155 62 whole grain- ground grain 19 .0163 180 ground grain- dust-chaff 3 .10 .0126 87 dust-chaff 4 .02 .0016 57 chaff 5 .27 .0081 ll weathered-moldy 7 0.00 0.0000 13 feed pellets 8 0.00 0.0000 10 81 9. Only elevators 6, 8, 9, and 13 had samples in which CNFB density exceeded 0.2 adults/gm.of sample material. Samples collected from inside the elevators were more frequently infested with CNFB and, infested with more CNFB than outside collected samples, although both categories con- tained samples in which CNFB density exceeded 0.2 adults/gm. Every inside site category listed in Table 7, except miscellaneous machinery (26) and around small storage bins (46), contained samples in which CNFB was present. CNFB was more commonly found and had higher mean densities in samples collected from leg boots (27), feed grinders (30), floor spills (35) and leg pits (37). However, densities exceeding 0.2 CNFB adults/gm. were also recorded from general floor samples (34) and samples collected from elevated platforms and catwalks (42). As With the three species previously discussed, CNFB was most common and abundant in samples collected from sites that involved some type of machinery. However, densities exceed- ing 0.2 CNFB adults/gm. were also recorded from concrete sites. CNFB was most commonly recorded in samples collected from sites in which there were greater than 3 bushels of residual grain material present. This category also contained the highest mean density of CNFB. However, densities exceeding 0.2 CNFB adults per gram.were also recorded from sites having less than 1 quart of material present. CNFB was the only insect species that was more frequent 82 and had a higher mean density in moist coded samples than in dry coded samples. Both categories contained samples in which CNFB density exceeded 0.2 adults/gm. Unlike RDFB, CNFB was more common in samples that con- tained a considerable portion of whole-seed grains, particu- larly corn, wheat and oats. Highest mean densities of CNFB were recorded from samples that contained a mixture of corn and oats, followed by samples that contained only wheat. Densities exceeding 0.2 CNFB adults gm. were recorded prim- arily from samples that contained corn either in combination or alone, although several other grain categories also yielded such densities. As suggested by the grain categories, CNFB seemed to prefer residual grain material that contained whole-seed grains and, indeed, the highest mean densities were recorded from condition categories 1 and 2. Oddly, samples consisting primarily of chaff (5) were most frequently infested with CNFB and this category also had a relatively high mean den- sity of CNFB. Densities exceeding 0.2 CNFB adults/gm” were recorded from samples consisting not only of whole-seed 1 grain (1) and ground grain (2,3) but also material consist- ing primarily of grain dust (6). The maximum density of .793 CNFB adults per gram.was recorded from a sample collected in a crawlspace beneath elevator 8. There were greater than 3 bushels of residue material present, which consisted primarily of dry whole- seed wheat. 83 Presented in Table 8 are the results of multiple re- ,gression analysis of CNFB density. No sampling variable, i.e. DSAM, WAAM, DINC, was associated with the observed variabil- ity of CNFB density. CNFB density was, however, positively associated with variability in CRYP density and CADL density, but these two species only explained about 2% of variation in CNFB density. Sawtoothed Grain Beetle The sawtoothed grain beetle (SWTH) was present in 12.6% of all samples collected during the survey with an average density of 0.0127 adults/gm. and a standard deviation of 0.149 adults/gm. The frequency of infestation and mean density of SWTH in each area of the state, elevator, and parameter category in which 10 or more observations were made are presented in Table 9. Again the frequencies and mean densities listed for level, site, structure, amount, mois- ture, grain and condition categories are for inside sites only. SWTH was recorded from samples collected from every area sampled and from 11 of the 17 elevators sampled. Elevators 11 and 12 had the highest frequency and mean density of SWTH among the elevators sampled. Densities exceeding 0.2 SWTH/ gm. were recorded from elevators 2, ll, 12, and 16. Samples collected from inside the elevators were more frequently infested with SWTH and had a higher mean density of SWTH than samples collected from outside. Outside collected samples never contained densities exceeding 0.2 SWTH 84 Table 8. Results of multiple regression analysis of CNFB density. Variables in the equation Variable b Standard Partial F ‘ error of b significance CRYP .0620 .0243 .011 CADL .7694 .3957 .052 constant -.0422. Analysis of variance Source df SS MS F Regression 2 .0442 .0221 4.93** Residual 554 2.4853 .0045 Multiple r .1322 2 R .0139 85 Table 9. Frequency and mean density of SWTH in the areas of the state, elevators and parameter categories. Criterion Category Code Relative Density N frequency (no./gm,) Area 1 .41 .1481 58 2 '.08 .0109 93 3 .08 .0021 132 4 .12 .0158 110 5 .10 .0026 52 6 .09 .0030 112 Elevator 2 .19 .0274 37 3 0.00 0.0000 35 4 0.00 0.0000 21 5 .19 .0050 27 6 0.00 0.0000 25 7 .11 .0034 52 8 0.00 0.0000 32 9 .11 .0019 44 10 .20 .0056 25 ll .67 .3866 15 12 .50 .1473 18 13 .13 .0063 38 14 .14 .0029 35 15 0.00 0.0000 39 l .21 .0367 42 17 0.00 0.0000 41 18 .15 .0282 27 In or out inside 1 .15 .0282 428 outside 2 .03 .0001 129 Level basement 1 .23 .0633 81 first 2 .17 .0282 245 second 3 .06 .0007 66 third 4 0.00 0.0000 22 fourth 5 .07 .0005 14 Site mills 24 .14 .0322 28 scales 25 .24 .0166 21 misc. machinery 26 .14 .0651 14 leg boots 27 .36 .1765 22 feed grinders 30 .38 .0108 13 general floor 34 .17 .0342 114 floor spills 35 .23 .0652 13 leg pits 37 .17 .0185 12 stairways 38 .20 .0066 10 platforms- catwalks 42 .05 .0003 21 86 Table 9. (cont'd.). Criterion Category Code Relative Density N frequency (no./gm.) Site beams-planks- ledges 45 0.00 0.0000 11 small bins 46 .10 .0003 10 inside walls 50 0.00‘ 0.0000 18 dump pit area 52 .14 .0101 21 Structure concrete 2 .13 .0251 151 wood 3 .12 .0102 175 mechanical 4 .09 .0078 35 other 5 .18 .0385 11 conc.-mech. 24 .46 .1253 37 wood-mach. 34 .16 .0350 37 Amount less than 1 qt. 1 .12 .0522 43 1 qt.-1 bu. 2 .14 .0282 175 l bu.-3 bu. 3 .14 .0177 122 greater than 3 bu. 4 .23 .0315 88 Moisture dry 1 .16 .0289 411 moist 2 .12 .0129 17 Grains no whole grain 0 .13 .0073 111 corn 1 .15 .0066 68 wheat 2 .15 .0106 34 oats 3 .36 .0671 ll navy beans 6 0.00 0.0000 37 corn-wheat 12 .03 .0001 31 corn-oats 13 .44 .1896 32 wheat-oats 23 .38 .0151 13 corn-wheat-oats 123 .17 .0214 24 corn-wheat-soys 127 0.00 0.0000 11 Condition whole-seed grain l .19 .0792 62 whole grain- ground grain 2 .18 .0178 180 ground grain- dust-chaff 3 .16 .0407 87 dust-chaff 4 .04 .0011 57 chaff 5 .36 .0253 ll weathered-moldy 7 0.00 0.0000 13 feedppellets 8 .20 .0070 10 87 adults/gm. SWTH was more common and had the highest mean density in samples collected from.basements than from any other level. Densities exceeding 0.2 SWTH adults gm. were recorded only from basements and first levels. SWTH was collected from every inside site listed in Table 9 except beams-planks-ledges (45) and bases of inside walls (50).. It was more frequently found in samples collected from legboots (27) and feed grinders (30). The highest mean density was recorded from leg boot (27) samples. Other sites with relatively high SWTH mean densities included miscellan- eous machinery (26), general floor samples (34) and flour spills (35). Densities exceeding 0.2 SWTH adults/gm" were recorded in samples collected from old bags of grain material (18), cleaning mills (24), scales (25), miscellaneous machinery (26), leg boots (27), floors (34, 35) and leg pits (37). ' SWTH, like the other species already discussed, was more common and had higher mean densities in sites involving some type of machinery, particularly at the bases of mach- . inery (structural codes 24, 34). High frequencies of infestation and mean densities in concrete—mechanical sites (24) reflect the results presented for level and site cate- gories, as basement walls and floors were always constructed of concrete. Also, leg boots and feed grinders were usually located on the basement floor. However, densities exceed- ing 0.2 SWTH adults/gm. were recorded from every structure 88 category listed in Table 9. SWTH was more frequent in samples collected from sites which had more than 3 bushels of residual material present, but had the highest mean density from sites which had less than 1 quart of material present. Densities exceeding 0.2 SWTH adults/gm. were recorded in each amount category. SWTH was generally more common and abundant in dry coded samples than in moist coded samples, although there was little difference in frequency and mean density between them. Both categories had samples in which SWTH density exceeded 0.2 adults/gm. Samples in which corn and oats were the predominant grains were more frequently infested with SWTH and contained, on the average, more SWTH than samples containing any other whole-seed grains. This category averaged nearly 2.0 SWTH adults/gm, however, most other categories had samples in which density exceeded this level. Excluding weathered-moldy material, every condition category had samples which contained SWTH. SWTH was more common in samples consisting of chaff but was more abundant. in samples consisting primarily of whole-seed grains. Only samples consisting of whole-seed grains (1,2) and ground grains (3) yielded densities of 0.2 or more SWTH adults/gm. of material. The maximum density of 2.084 SWTH adults/gm. was re- corded from a general floor sample collected from the first floor inside elevator 11. The floor was concrete and there 89 was less than 1 quart of material present which consisted primarily of ground grain, dust and chaff. Presented in Table 10 are the results of multiple re- gression analysis of SWTH density. The only variable includ- ed in the equation was the log capacity of the elevator. SWTH density was negatively associated with the variation in elevator size, but LCAP explained only 1% of the variation observed in SWTH density. Yellow Mealworm The yellow mealworm (YWMW) was present in 33.9% of all samples collected during the survey with an average density of 0.0218 larvae/gm. and a standard deviation of .070 larvae/ gm. The frequency of infestation and mean density of YMWM in each area of the state, elevator and parameter category in which 10 or more observations were made are presented in Table 11. Again the frequencies and mean densities present- ed for level, site, structure, amount, moisture, grain and condition categories are for inside collected samples only. YWMW was present in samples collected from every area of the state sampled and 16 of the 17 elevators sampled. Only elevator 4 did not yield samples in which YWMW was present and the other elevators (2,3) located in this area (2) were less frequently infested with YWMW than were the other elevators. Samples collected from elevators 6, 9, 10, and 12 were more frequently infested with YWMW and yielded more YWMW larvae/gm. than samples from the other elevators. 90 Table 10. Results of multiple regression analysis of SWTH density. Variables in the equation Variable b Standard Partial F error of b significance LCAP -.0025 .0010 .014 constant .1499 Analysis of variance Source df SS MS F Regression l .1340 .1340 6.12* Residual 555 12.1525 .0219 Multiple r .1044 R2 .0091 91 Table 11. Frequency and mean density of YWMW in the areas of the state, elevators and parameter categories. Criterion Category Code Relative Density N frequency, (no./gm.) Area 1 .53 .0355 58 2 .09 .0117 93 3 .46 .0305 132 4 .24 .0061 110 5 .35 .0242 52 6 .40 .0269 112 Elevator 2 .16 .0284 37 3 .06 .0010 35 4 0.00 0.0000 21 5 .22 .0045 27 6 .48 .0454 25 7 .38 .0235 52 8 .47 .0236 32 9 .59 .0445 44 10 .56 .0331 25 11 .27 .0126 15 12 .72 .0581 18 13 .42 .0317 38 14 .34 .0236 35 15 .44 .0251 39 16 .40 .0129 42 17 .15 .0020 41 18 .11 .0019 27 In or out inside 1 .41 .0255 428 outside 2 .12 .0095 129 Level basement 1 .36 .0057 81 first 2 .42 .0293 245 second 3 .29 .0276 66 third 4 .64 .0244 22 fourth 5 .57 .0648 l4 Site mills 24 .32 .0298 28 scales 25 .52 .0188 21 misc. machinery 26 .21 .0155 14 leg boots 27 .45 .0116 22 feed grinders 30 .54 .0065 13 general floor 34 .36 .0250 114 floor spills 35 .46 .0184 13 leg pits 37 .33 .0062 12 stairways 38 .40 °0119 10 92 Table 11. (cont'd.). Criterion Category Code Relative Density N frequency (no.1gm.) Site platforms- catwalks 42 .52 .0263 21 beams-planks- ledges 45 .27 .0048 11 small bins 46 .40 .0193 10 ‘inside walls 50 .39 .0638 18 dump pit area 52 .48 .0176 21 Structure concrete 2 .37 .0180 151 wood 3 .42 .0381 147 mechanical 4 .29 .0038 35 other 5 .27 .0063 11 conc.-mech. 24 .57 .0313 37 wood-mech. 34 .46 .0232 37 Amount less than l qt. 1 .21 .0160 43 l qt.-l bu. 2 .36 .0296 175 l bu.-3 bu. 3 .48 .0287 122 greater than 3 bu. 4 .50 .0174 88 Moisture dry 1 .42 .0262 411 moist 2 .18 .0071 17 Grains no whole grain 0 .39 .0401 111 corn 1 .47 .0293 68 wheat 2 .35 .0074 34 oats 3 .64 .0292 .ll navy beans 6 .08 .0020 37 corn-wheat 12 .42 .0235 31 corn-oats 13 .50 .0316 32 wheat-oats 23 .38 .0039 13 corn-wheat-oats 123 “.50 .0360 24 corn-wheat-soys 127 .36 .0317 11 Condition whole-seed grain 1 .26 .0040 62 whole grain- ground grain 2 .47 .0232 180 ground grain- dust-chaff 3 .39 .0146 87 dust-chaff 4 .44 .0556 57 chaff 5 .55 .0300 ll weathered-moldy 7 .08 .0719 13 feed pellets 8 .30 .0190 10 93 Densities exceeding 0.2 YWMW larvae/gm. recorded from 8 of the 17 elevators sampled including elevators 6, 7, 8, 9, 12, 13, 14, and 15. YWMW was far more common and abundant in samples collected from inside the elevators than from the outside, although both categories had samples in which the density of YWMW exceeded 0.2 larvae/gm. Unlike most of the species already discussed, YWMW was more common and abundant in samples collected from upper levels (3,4) of the elevators than in the basements. Den- sities exceeding 0.2 YWMW larvae/gm. were recorded from samples collected on the first, second, and fourth levels. YWMW was present in samples collected from every site listed in Table 11. There was very little difference in the frequency of infestation among the sites, although there were considerable differences in the observed densities. The bases of inside walls (50) had samples that contained the highest mean density of YWMW. Densities exceeding 0.2 YWMW larvae/gm. were reared from cleaning mills (24), general floor samples (34), head houses (40), elevated cat- walks and platforms (42), the bases of storage silos (48) and the bases of storage silos (48) and the bases of inside walls (50). Like most of the species already discussed, YWMW was more common and abundant in samples collected from sites involving the bases of machinery (structural codes 24, 34), although entirely wooden structures also had high 94 frequencies of infestation and mean densities of YWMW. Densities exceeding 0.2 YWMW larvae/gm. were from concrete, wooden and concrete-mechanical structures. In general, the frequency of YWMW infestation increased as the amount of residual material present at the site in- creased. However, there was very little difference in YWMW mean density among the amount categories and densities ex- ceeding 0.2 YWMW larvae/gm. were recorded from each category. YWMW was more common and abundant in dry coded samples than in moist coded samples and only dry coded samples yielded densities exceeding 0.2 YWMW larvae/gm. Samples in which oats and corn were the predominant whole-seed grains were more frequently infested with YWMW than were other samples. However, the highest mean density of YWMW was recorded from samples in which little or no whole-seed grain was present. YWMW was less common in samples consisting primarily of whole-seed grain and in samples consisting primarily of weathered-moldy material. The highest mean density, however, was recorded in the weathered-moldy category and this occurred because the only sample in this category infested with YWMW contained more than 0.8 YWMW larvae/gm. of material. Densities exceeding 0.2 YWMW larvae/gm. were also recorded from samples consisting of a whole-seed grain ground-grain mixture (2), samples consisting primarily of chaff and dust (4) and samples consisting primarily of dust (6). ‘95 The maximum density of 0.935 YWMW larvae/gm. of mat- erial was recorded from a sampled collected from the wooden floor of a small extraneous room inside elevator 2. There was between 1 quart and l bushel of dry material pres- ent which consisted primarily of weathered-moldy residues. Presented in Table 12 are the results of multiple re- gression analysis of YWMW density. Two insect species, the closely related dark mealworm, Tenebrio obscurus (DKMW) and the predaceous windowpane fly (SCNO), Scenopinus fenestralius were postively associated with YWMW density variability. Also, one sampling variable, the sample weight (WSAM) was negatively associated with variability in YWMW density. These three variables, i.e., SCNO, DKMW, WSAM, explained about 6% of the variation observed in YWMW density. Black Carpet Beetle The black carpet beetle was the most commonly found storage species in this survey. This almost ubiquitous species was present in 53.5% of all the samples collected during the survey with an average density of 0.1243 larvael' gm. and a standard deviation of .497 larvae/gm. of material. BKCB was the only species to be collected from every eleva- tor sampled and was present in at least 20% of the samples collected from each elevator. Six of 17 elevators aver- aged over 0.1 BKCB larvae/gm. of material. This species has but one generation per year and its numbers were not expected to increase during the incubation period. Sampling 96 Table 12. Results of multiple regression analysis of YWMW density. Variables in the equation Variable b Standard Partial F error of b significance SCNO 2.7628 .6953 .001 DKMW .8634 .2897 .003 WSAM .0001 .0001 .052 constant .0271 Analysis of variance Source df SS MS F Regression 3 .1602 .0534 11.38** Residual 553 2.5939 .0047 Multiple r .2412 R2 .0582 97 Table 13. Frequency and mean density of BKCB in the areas of the state, elevators and parameter categories. Criterion Category Code Relative Density N frequency, (no./gm.) Area 1 .59 .0610 58 2 .53 .0393 93 3 .57 .1091 132 4 .41 .0136 110 5 .56 .2842 52 6 .59 .2626 112 Elevator 2 .51 .0399 37 3 .51 .0246 35 4 .57 .0628 21 5 .70 .3959 27 6 .40 .1635 25 7 .50 .0652 52 8 .50 .0940 32 9 .70 .1758 44 10 .72 .1082 25 11 .20 .0179 15 12 .72 .0313 18 13 .61 .5909 38 14 .57 .1119 35 15 .59 .0778 39 16 .40 .0339 42 17 .41 .0226 41 18 .41 .0418 27 In or out inside 1 .65 .1544 428 outside 2 .15 .0245 129 Level basement 1 .44 .0421 81 first 2 .67 .1419 245 second 3 .73 .3165 66 third 4 .91 .1541 22 fourth 5 .86 .2588 14 Site mills 24 .75 .1348 28 scales 25 .71 .0880 21 misc. machinery 26 .79 .1694 14 leg boots 27 .45 .0131 22 feed grinders 30 .62 .0925 13 general floor 34 .64 .1071 114 floor spills 35 .46 .0425 13 leg pits 37 .33 .0336 12 stairways 38 .90 .3599 10 Table 13 (cont'd.) Criterion Category Code Relative Density N frequency (no./gm.) Site platforms- catwalks 42 .86 .3969 21 beams-planks- 1edges 45 .73 .1437 11 small bins 46 .60 .0938 10 'inside walls 50 .61 .6291 18 dump pit area 52 .57 .1168 21 Structure concrete 2 .50 .1126 151 wood 3 .73 .1709 147 mechanical 4 .74 .1953 35 other 5 .75 .7553 ll conc.-mech. 24 .62 .0950 37 wood-mech. 34 .78 .1345 37 Amount less than 1 qt. 1 .60 .3618 43 1 qt.-l bu. 2 .66 .1729 175 1 bu.-3 bu. 3 .75 .1080 122 greater than 3 bu. 4 .52 .0806 88 Grains no whole grain 0 .62 .3233 111 corn 1 .68 .1378 68 wheat 2 .53 .0450 34 oats 3 .55 .0410 ll navy beans 6 .49 .0522 37 corn-wheat 12 .71 .1130 31 corn-oats 13 .72 .1460 32 wheat-oats 23 .77 .0958 13 corn-wheat-oats 123 .63 .0375 24 corn-wheat-soys 127 .91 .1405 11 Condition whole-seed grain 1 .52 .0337 62 whole grain- ground grain 2 .73 .0884 180 ground grain- dust-chaff 3 .70 .2619 87 dust-chaff 4 .61 .1595 57 chaff 5 .45 .1344 ll weathered-moldy 7 .15 .0493 13 feed pellets 8 .70 .0468 10 99 variables, i.e., DSAM, WSAM, DINC, were expected to have a minimal affect on the observed BKCB density. This is sup- ported by no significant correlations between BKCB density and these sampling variables. Therefore, because of the large numbers of BKCB and the minimal amount of extraneous variation units due to sampling variables, the results pre- sented for this species are more reliable. The frequency of infestation and mean density of BKCB in each area of the state, elevator and parameter category in which 10 or more observations were made are presented in Table 13. Again, the frequency and mean density presented for level, site, structure, amount, moisture, grain and condition categories are for inside collected samples only. Generally, those elevators more frequently infested with BKCB also yielded samples containing higher mean den- sities of BKCB. Elevators 5 and 13 averaged over 0.3 BKCB larvae/gm. in their respective samples. Elevators 5, 6, 9, l3, l4 yielded samples in which the density exceeded one or more BKCB larvae/gm. of sample material. BKCB was more common and abundant in samples collected from inside the elevators than in outside collected samples. Both of these categories contained samples in which BKCB density exceeded 1.0 1arvae/gm., but more so in samples collected from.the inside. BKCB was recorded more frequently from samples collected on the upper levels of elevators and, unlike most of the other species discussed, it was least common and least 100 abundant in samples collected from basements. Densities exceeding 1.0 BKCB larvae/gm. of material were recorded from samples collected from every level. Every inside site category, in which 10 or more obser- vations were made, contained samples infested with BKCB. The highest mean density of BKCB was recorded from samples collected from.stairways (38), elevated platforms and cat- walks (42) and the bases of inside walls (50). Ten of the 14 sites listed in Table 13 yielded samples in which the density exceeded 0.4 BKCB larvae/gm. Densities exceeding 1.0 BKCB larvae/gm. were recorded from samples collected from miscellaneous machinery (26), general floor (34), stairways (38), head houses (40), elevated platforms and catwalks (42), inside manlifts (44) and the bases of inside walls (50). There was little difference in the frequency of infes- tation and mean density of BKCB in the different structural categories. Every structural category yielded samples con- taining more than 0.8 BKCB larvae/gm. of material. BKCB was more abundant, on a per gram basis, in sites., where less than a quart of material was present. It was less common and less abundant in sites where more than 3 bushels of material were present. Densities exceeding one BKCB larvae per gram were recorded from each amount category. BKCB was more common in dry coded samples than in moist coded samples and on the average about 40 times as abundant in dry coded samples. Only dry coded samples yielded densities exceeding 0.2 BKCB larvae/gm. 101 Of the whole-seed grain and beans, BKCB seemed to pre- fer corn and corn in combination with wheat or oats. The highest mean density of BKCB, however, was recorded from samples in which no whole-seed grain or beans were present. Samples consisting primarily of whole-seed grain or beans and samples consisting of weathered-mold material were less frequently infested with BKCB and had lower mean den- sity than were other condition categories. The highest mean density of BKCB was recorded from samples consisting of a mixture of ground grain, dust and chaff. Only samples con- sisting of ground grain, dust, and chaff or mixtures of these yielded densities exceeding 0.8 BKCB larvae/gm. The maximum density of 7.420 BKCB larvae/gm. of material was collected from the base of an inside wall on the first floor of elevator 13. There was less than 1 quart of material present which consisted primarily of dry grain dust. Presented in Table 14 are the results of multiple re- gression analysis on BKCB density. The size of the elevator (LCAP) and two insect species, SCNO and the cadelle beetle (CADL) are shown to be positively associated with the variation in the observed BKCB density. Together, these three variables explained only 4% of observed variability in BKCB density. 102 Table 14. Results of multiple regression analysis of BKCB density. Variables in the equation Variable b Standard Partial F error of b significance SCNO 17.2072 4.8748 .001 LCAP .0092 .0033 .006 CADL 7.3742 2.8820 .011 constant -.3848 Analysis of variance Source d£_ SS MS F Regression 3 6.0866 2.0289 8.55** Residual 553 131.1836 .2372 Multiple r .2106 32 .0443 103 Dark Mealworm The dark mealworm (DKMW) was present in 8.1% of all samples collected during the survey with an average density of 0.002 larvae/gm. and a standard deviation of 0.010 larvae/gm. DKMW was present in samples collected from 5 of the 6 areas of the state. In addition to the 3 elevators in area 2, DKMW was not found in samples collected from elevators 9 and 11. Generally, DKMW was more common in samples collected inside the elevators than those collected from the outside. Like most other species discussed, DKMW was more common in basement sites and sites involving some type of grain machinery. The maximum.observed DKMW was 0.131 larvae/gm. of sample material. Cadelle Beetle Cadelle beetles (CADL) were present in 17.8% of all the samples collected during the survey with average density of 0.001 larvae/adults/gm. and a standard deviation of 0.007 larvae/adults/gm. CADL was found in samples collected from every area of the state and in samples collected from 13 of. the 17 elevators sampled. CADL was more common in inside collected samples which consisted, at least in part of wholeéseed grains, particularly corn, wheat, and oats. As with most other species, CADL was commonly found in sites involving some type of grain machinery. The maximum.observed density of CADL was 0.144 larvae/adults/gm. of sample mat- erial. 104 Larger Black Flour Beetle The larger black flour beetle (LBFB) was present in 2.7% of all the samples collected during the survey with an average density of .001 adults/gm. and a standard deviation of .007 adults/gm._ LBFB wascollected from 4 of the 6 areas of the state sampled but only from 6 of the 17 elevators sampled. The maximum observed density of LBFB was 0.144 adults/gm. of sample material. Drugstore Beetle The drugstore beetle (DGSB) was found in 2.1% of all the samples collected during the survey with an average density of less than .001 adults/gm. DGSB was found in 3 of the 6 areas of the state sampled and found in only 6 of the 17 elevators sampled. The maximum observed density for DGSB was 0.123 adults/gm. of sample material. Ptinids Ptinids (PTND) or spider beetles of undetermined species were.present in 5.7% of the samples collected during the survey with an average density of 0.001 adults/gm. and a standard deviation of 0.004 adults/gm. PTND were found in 4 of the 5 areas of the state sampled and in 10 of the 17 elevators sampled. The maximum observed density of PTND was 0.056 adults/gm. of sample material. 105 Mediterranean Flour Moth The Mediterranean flour moth (MDFM) was the most com- monly found Lepidoptera during the study. It was present in 2.3% of all samples collected with an average density of 0.002 adults/gm. and a standard deviation of 0.019 adults/gm. MDFM was found in 4 of 5 areas of the state sampled in 7 of 17 elevators sampled. MDFM was never collected in moist cod- ed samples and it was most commonly found in whole-seed grain and ground grain mixtures (condition categories 1,2,3). The maximum.cbserved density of MDFM was 0.302 adults/gm. of sample material. Mites Undetermined mite species were present in 4.1% of all the samples collected during the survey. Mites were not in- dividually counted as were the insect species during the survey, mites were simply recorded as being either absent or present. Mites were found in samples collected from 3 of the 6 areas of the state and in 5 of 17 elevators sampled. Mites were more often found in outside collected samples. Windowpane Fly The windowpane fly (SCMO), Scenopinus fenestralis, is reportedly a predator of the immature stages of storage in- sects. Larvae of this fly are very characteristic; they are long, white, thread-like legless insects with well- developed, black head capsules. SCNO was present in 17.8%. of all samples collected during the survey with an average 106 density of 0.0016 larvae/gm. and a standard deviation of 0.004 larvae/gm. Because of its predaceous behavior, relatively high frequency in the samples and its relatively strong correlations with 5 other storage species, SCNO was subjected to the same analyses as the 7 common storage pests. SCNO was found in samples collected from every eleva- tor sampled. In general, SCNO was more common in samples from elevators in which yellow mealworms and black carpet beetles were more frequently fOund. SCNO was more common and abundant in samples collected from the inside of eleva- tors. SCNO was found least frequent in basement samples and about equally frequent in samples collected from the other levels. Basement samples also had the smallest mean density of SCNO. Of the site categories, SCNO was more common and abund- ant in samples collected from scales (25) and from the bases of inside walls (50). Generally, those sites that were frequently infested with BKCB, YWMW and DKWM were also the sites in which SCNO was found. No consistent pattern developed in the frequency and mean density of SCNO in the structural and amount categories. Each category had samples containing SCNO. SCNO was not found in any of the moist coded samples collected inside the elevators. As one might expect, the type of whole-seed grain and beans present in the sample had very little effect on the occurrence and abundance of SCNO. Those grain categories with samples frequently infested with other storage species 107 also contained SCNO. SCNO was present in samples belonging to each condition category. It was less frequent in sam- ples consisting of weathered-moldy material and those con- sisting primarily of whole-seed grains. SCNO was particu- larly abundant in samples consisting of dust (6) and of chaff (5) or of a combination of dust and chaff (4). These con- dition categories were generally those which contained the highest densities of BKCB, YWMW and DKWM. Presented in Table 15 are the results of multiple re- gression analysis of SCNO density. Four insect species (YWMW, BKCB, LBFB, DKMW) and.two sampling variables (DSAM, WSAM) were shown to be significantly associated with the observed variability of SCNO density. Together these variables explained about 10% of the variation in SCNO den- sity. Inclusion of the sampling variables (DSAM; WSAM) into the multiple regression equation only explained 1% more of the variability than did an equation including just the insect species. Number of Species In many samples, more than one species was present and no insect species occurred more often by itself than it did in combination with another storage species. As stated in the methods section, the number of different storage species present in the sample is considered a separate variable. The number of species of the 14 listed in Table 1, present 108 Table 15. Results of multiple regression analysis of SCNO density. . Variables in the equation Variable b Standard Partial F error of b significance YWMW .0091 .0025 .001 BKCB .0011 .0003 .001 LBFB .0779 .0246 .002 DKMW .0421 .0173 .015 WSAM .0001 .0001 .037 DSAM .0001 .0001 .049 constant -.0046 Analysis of variance Source SS MS F Regression 7 .0010 .0002 8.90** Residual 549 .0090 .0001 Multiple r .3192 R2 .1019 109 in the samples ranged from 0 to 10. The average number per sample was 2.43 species. To test whether the number of species was affected by the same physical factors influencing an individual species, a separate one-way analysis of variance of the density of different species among the elevators and parameter cate- gories was performed. Only the amount categories failed to show a significant component of variation in the number of species in the samples. This suggests that species diversity, as well as individual species density, in residual populations is influenced by the physical characteristics of the site and of the grain material that accumulates in that site. The frequency of 1 to 10 species present in the samples was calculated for each area of the state, elevator and parameter category and is presented in Appendix C. The frequencies given for level, site, structure, amount, mois- ture, grain and condition categories are for inside sites only. Of all the samples collected, 24% had no species, 18.5% had 1 species, 16% had 2 species, 12.2% had 3 species, 10% had 4 species, 7.5% had 5 species, 6.3% had 6 species, 3.4% had 7 species, 2% had 8 species and one sample had 10 of the common species present. Those elevators located in area 2 (2,3,4) averaged only 1 or less species/sample and had fewer per sample than the other elevators. Elevators 10, 13, 14 and 15 averaged over 3.5 species/sample and elevator 12 averaged over 4.5 species/sample which was the 110 greatest of any elevator. All but 4 of the elevators yielded samples in which 6 or more species were collected and over 40% of samples collected from elevators 12 and 14 had 6 or more species present. Every sample collected from elevator 12 contained at least one species. Inside samples averaged over 2.8 species/sample, while outside collected samples averaged just over 1 species. Both inside and outside collected samples contained 6 or more species, even though considerably more outside samples did not contain a single species. As with most individual species, samples collected from the basements and third levels also averaged more species than did the other levels. Every level category except the 5th had samples in which 6 or more different species were collected and the frequency distribution of species/sample is similar among the level categories. Every inside site category in which 10 or more observa- tions were made averaged over 2 species/sample. The high- . est average was recorded from feed grinders (30) with 4.8 species/sample. Scales (25), leg boots (27) and floor spills (35) averaged over 3 species/sample. Over 45% of (the samples collected from leg boots (27), feed grinders (30) and floor spills (35) contained 5 or more species. As with the frequency of infestation and relative abundance of several individual species, sites involving the bases of machinery (structure categories 24,34) also 111 averaged more species/sample. These two categories were the only structure types to average over 3 Species/sample. Each structure category had samples in which 6 or more species were collected. Of the samples collected from concrete-mechanical sites, 38% contained 6 or more species. ’ Only sites where less than 1 quart of residual material was present averaged less than 2 species/sample and the other amount categories averaged less than 3 species/ sample. Only sites which had more than 1 quart of material present had samples containing 6 or more species. Dry coded samples averaged more species/sample than did moist coded samples. Almost all inside samples contain- ing 3 or more species were dry coded. Samples consisting, at least in part, of whole-seed small grains and corn either alone or in combination aver- aged more species/sample than did those consisting of navy beans or those with little or no whole-seed grains present. Navy bean samples averaged less than 1 Species/sample and samples without whole-seed grains averaged less than 2 species/sample. All other grain categories involving corn, wheat or oats averaged over 3 species/sample. Half of the samples consisting of navy beans did not contain a single species and no navy bean sample contained more than 3 species. Only 4% of the corn samples, 9% of the oat samples and 6% of the corn-oat samples were unin- fested. Every grain category, except those with navy or soy beans, had samples which contained 6 or more species. 112 Weathered-moldy material was the only condition cate- gory to average less than 1 species/sample. As implied by the grain categories, samples consisting of a mixture of whole-seed grains, ground grain, dust and chaff averaged more species/sample than did‘the other condition categories. This was the only grain category to average more than 3 species/sample. Every grain category, except weathered-moldy material, had samples in which 6 or more species were collected. 3 The maximum.number of 10 species found in a single sample was collected from the base of a leg boot in the base- ment of elevator 14. There was between 1 quart and 1 bushel of residual grain material present which consisted of a mixture of whole-seed corn and oats, ground grain, dust and chaff. ANOVA Results One—way analysis of variance was used to test the hypothesis that the physical environment of the county eleva— tor ecosystem, e.g., elevator, level, condition, significant- ly affect the distribution of residual insect populations. Significant F statistics in this analysis would imply the criterion or parameter used to stratify the residual material differed significantly from that of a completely random.criterion. Since this analysis assumes a random rather than a fixed model in this case, the intent was not to detect differences among individual strata (category) means but rather to associate variability in insect density 113 with variability in the parameter categories. Presented in Table 19 are the results of the analyses of variance performed with the observed density of 7 common storage species encountered during this study as the dependent variables and the parameter categories as the independent variables. Elevator was the only parameter to be significantly associated with the variability in den- sity of all 7 species tested. The moisture content of the grain was the only parameter not to be associated with the density of any species tested. The effects of the other parameters seemed to be species-specific and no general patterns could be demonstrated. Species Combinations Presented in Appendix D are all combinations of the 14 species observed in the samples collected during the sur- vey and the number of times these combinations occurred. Only mites were found more often by themselves than in combination with other species. Of the 23 samples in which mites were observed, 20 contained only mites. All other species were found in combination with at least one species in over 85% of the samples containing these species. Of the 89 samples with just 2 species present: 22 contained YWMW and BKCB; 11 contained BKCB and SCNO; 10 contained GRWV and CRYP; and 4 contained BKCB and CRYP. Other two-way combinations occurred in less than 4 samples. 114 Of the 68 samples with just 3 species present; 9 contained YWMW, BKCB and SCNO; 7 contained GRWV, YWMW and BKCB: and 4 contained GRWV, BKCB and CADL. All other three- way combinations occurred in less than 4 samples. Of the 55 samples with just 4 species present: 6 con- tained GRWV, CRYP, BKCB, and CADL; 5 contained GRWV, CRYP, BKCB, and CADL; and 4 contained GRWV, YWMW, BKCB and SCNO. The most common 5-way combination of species collected was GRWV, CRYP, YWMW, BKCB, and CADL which occurred in 5 samples. Generally, unique 6-way or higher order combin- ations were observed in 2 or less samples and usually in- volved GRWV, CRYP, RDFB, CNFB, YWMW, SWTH, BKCB or SCNO as the major elements. Presented in Table 16 are the observed relative frequencies for each possible two-way combination of eight commonly found storage species. This does not necessarily mean that these two-way combinations were the only species present, only that among the species present this combin- ation was included. YWMW and BKCB occurred together in the. samples more often than any other pair of species. This combination was in 29.3% of the samples. GRWV and BKCB were present together in 25.7% of the samples, GRWV and YWMW in 18.7%, GRWV and CRYP in 17.1%, CRYP and BKCB in 15.6%, and BKCB and SCNO were present together in 15.3% of the samples. Presented in Table 17 are the observed relative frequencies of all possible three-way combinations including 115 Table 16. Frequency of common two-way combinations of species in residual grain material samples. Combination Frequency Combination Frequency (7.) (7.) GRWV-CRYP 17.1 GRWV-RDFB 6.1 GRWV-CNFB . 8.8 GRWV-SWTH 7.9 GRWV-YWMW 18.7 GRWV-BKCB 25.7 GRWV-SCNO 9.7 CRYP—RDFB 5.4 CRYP-CNFB 7.0 CRYP-SWTH 6.1 CRYP-YWMW 12.9 CRYP-BKCB 15.6 CRYP-SCNO 5.4 RDFB-CNFB 2.3 RDFB-SWTH 2.1 RDFB-YWMW 6.3 RDFB-BKCB 9.0 RDFB-SCNO 5.4 CNFB-SWTH 4.7 CNFB-YWMW 7.2 CNFB-BKCB 9.0 CNFB-SCNO 3.2 SWTH-YWMW 6.6 SWTH-BKCB 9.2 SWTH-SCNO 3.8 YWMW-BKCB 29.3 YWMW-SCNO 10.8 BKCB-SCNO 15.3 116 Table 17. Frequency of common three-way combinations of species in residual grain material samples. Combination Frequency Combination Frequency (7.) (%) GRWV-CRYP-RDFB 3.4 GRWV-CRYP-CNFB 6.5 GRWV-CRYP-SWTH 5.0 GRWV-CRYP-YWMW 9.3 GRWV-CRYP-BKCB 11.5 GRWV-CRYP—SCNO 4.1 GRWV-RDFB-YWMW 3.9 GRWV-CNFB-YWMW 5.7 GRWV-SWTH-YWMW 5.2 GRWV-YWMW-BKCB 16.9 GRWV-YWMW-SCNO 7.0 GRWV-RDFB-BKCB 4.1 GRWV-CNFB-BKCB 6.8 GRWV-SWTH-BKCB 6.5 GRWV-BKCB-SCNO 8.6 CRYP-RDFB-BKCB 4.1 CRYP-CNFB-BKCB 5.2 CRYP-SWTH-BKCB 4.1 CRYP-YWMW-BKCB 10.6 CRYP-BKCB-SCNO 4.3 RDFB-YWMW-BKCB 5.6 CNFB-YWMW-BKCB 6.1 SWTH-YWMW-BKCB 5.4 YWMW-BKCB-SCNO 9.9 RDFB-BKCB-SCNO 3.9 CNFB-BKCB-SCNO 2.7 3. SWTH-BKCB-SCNO 117 the 6 most common pairs and one other of the 8 common species. The combination of GRWV, YWMW and BKCB occurred in 16.5% of all the samples, GRWV, CRYP and BKCB occurred together in 11.5%, CRYP, YWMW and BKCB in 10.6%, and YWMW, BKCB and SCNO occurred together in 9.9% of the samples collected. Species Correlations Presented in Table 18 are the significant correlation coefficients between species densities and between species density and the sampling variables, i.e., DSAM, WSAM, DINC. Also included are the significant correlations between species and the size of the elevator (LCAP) from.which the sample was collected. As expected, there was a strong correlation, .8194, between variability of DSAM (Julian date sample was collected) and DINC (number of days the sample was incubated). Ideally, this correlation coefficient should have been near 1.0 as the time between sample collection and sample evaluation was scheduled to be the same for all samples. However, as mentioned in the methods section, this schedule was not exactly kept because of the time required to evaluate the °samples. The variability in the density of 5 species (GRWV, DKMW, CADL, MITE, SCNO) was also associated with DSAM. This should not be surprising, since samples were collected over a six week period and one would expect insect numbers 118 Table 18. Pearson's correlation coefficients between insect density and other continuous variables. Variables Coefficient; Significance DSAM-DINC .8194 .001 " -GRWV .1175 .005 " -DKWM .1014 .017 " -CADL .0866 .041 " -MITE .1341 .002 " -SCNO .0907 .032 LCAP-DINC .3600 .001 " -SWTH .1044 .014 " -BKCB .1122 .008 " -LBFB .0991 .019 " -PTIN .1087 .010 WSAM-YWMW .0994 .019 " -SCNO .1107 .009 DINC-GRWV .1004 .018 CADL-BKCB .0933 .028 " -GRWV .2158 .001 CRYP-CNFB .1067 .012 YWMW-DKWM .1465 .001 SCNO-YWMW .1920 .001 " -DKMW .1335 .002 " -BKCB .1457 .001 " -LBFB .1328 .002 " -PTIN .0898 .034 119 Table 19. Summary of One-way Analysis of Variance significant F statistics. Independent Dependent Variable Variable GRWV CRYP RDFB CNFB SWTH YWMW BKCB Elevator ** * ** ** ** * ** In or Out * NS * NS * * ** Level NS ** NS * NS * ** Site NS NS ** ** NS ** ** Structure NS ** NS ** * ** NS Amount NS NS NS ** NS NS * Moisture NS NS NS NS NS NS NS Grains ** NS NS NS ** NS NS Condition ** NS NS NS NS ** ** NS - not significant, * - significant at =.05, ** - highly significant at -.01 120 to increase during this time in the elevator system. The density of two species, YWMW and SCNO, was nega- tively associated with the variation of sample weight (WSAM). Apparently, as sample weight decreased the density of these two species increased more than would be expected due to chance along. ° GRWV was the only insect species whose density was significantly correlated with DINC.- Apparently, as the length of the incubation increased among the samples, there was a corresponding increase in GRWV density. It would seem that more species would have been correlated with this sampling variable as many can develop from egg to adult in the amount of time the samples were incubated. The density of four species was significantly corre- lated with the size of the elevator (LCAP): BKCB and LBFB were positively associated; SWTH and PTND were negatively associated. However, DINC showed the strongest correla- tion with LCAP and no explanation for this can be given other than this association was an artifact of the order in which the elevators were sampled. Because of this, very little can be said about the correlations between LCAP and the four species since these correlations might also be artifact of the order in which the elevators were sampled. CADL was positively associated with both GRWV and BCKB density. Possibly, the common preference of whole- seed grains in GRWV and CADL (U.S.D.A. 1978) explains this correlation and BKCB larvae may provide a prey source 121 for the predaceous CADL. By far SCNO density was correla- ted with the most number of species. Three of these species, YWMW, DKMW and BKCB, were usually present as larvae in the samples containing SCNO and serve as prey for this common predator. The correlations between YWMW-DKMW and CRYP-CNFB probably reflect similar preferences in habitats between these pairs. These correlations between variables do not prove a- cause and effect relationship, but only that the association in rhe variation of their densities was significantly different from what would be expected in random population densities. DISCUSSION The initial intent of this study was of an applied rather than ecological nature in that the objectives were to determine the species commonly found in residual mater- ial and to determine the sites in the elevators frequently harboring insects. This information should be immediately useful to the grain industry as it shows several serious pest species to be common residents in residual material and provides indications as to where sanitation practices might be intensified to reduce these pOpulations. It was not until a preliminary study was conducted that the objectives were expanded to include ecological in- formation on the possible factors affecting the distribution. and abundance of residual insect populations in the elevator ecosystem. In order to accomplish this, possible ecological parameters which are particular to the elevator system had 1 to be determined and then tested. Based on the available literature and observations made during the preliminary study, the parameter categories presented in this report were thought to describe the variation of several physical and biological variables affecting residual populations. 122 123 This study was not able to prove a cause and effect relationship between the abundance of a particular species and a certain parameter category or the observed density of another species. The hypothesis tested in this study by means of the F statistic in either one-way analysis of variance or multiple regression analysis was whether or not the observed variability of a particular species density was significantly associated with a certain parameter or another species density. No doubt, the sampling variables, i.e., DSAM, WSAM, DINC, inflated the error term in both of these analyses. These sources of extraneous variation in the observed insect density would reduce the value of the F statistic which would be a conservative effect. The effect would be conservative because it would reduce the ability declared a significant association even though such an association might exist. The variability in insect density associated with DSAM and DINC was unavoidable. In the case of DSAM, l7 elevators could not have been sampled all on the same day or even in . the same week. DSAM variability might have been minimized by randomizing the order in which the elevators were sampled. However, this was not possible as permission to sample had to be obtained beforehand and because of the additional cost in time and resourCes. In the case of DINC, it was not physically possible for one person to evaluate in one week the amount of sample material collected from three elevators. Therefore the incubation period varied among the samples and 124 gradually increased from samples collected first to those collected in the final week. Insect density was expected to increase in the samples as the initial density at the site of collection increased through the season and as incubation period increased. It was expected the relative frequency of infestation in the samples to be less affected by the vari- ability in DSAM and DINC as this was computed solely on the basis of the presence or absence of a species. The variability associated with the size or weight of the sample, WSAM, was in a sense unavoidable, although a strict standard volume size sample might have been a satis- factory solution. However, there are several problems even with a standard volume sample. Samples were to represent residual material collected from sites which vary, first, in respect to the area or floor space and, second, in respect to the volume of residual material present at the site. Thirdly, samples were to represent residual material which varied with respect to the type of grain and beans present and the con- sistency of the non-whole-seed grain material present. Samp- ling residual material in the elevator ecosystem is not as simple as sweeping insects with a net in a wheat field. Solomon (1955) suggested expressing storage insect density as the number per gram of grain material. Density expressed in this way would be a function not only of the number of individuals but also the mass of the sample material. This proved to be a satisfactory method to obtain a relative measure of abundance for this study, as the density of only 125 two species (YWMW and SCNO) was significantly correlated with WSAM. Despite the extraneous variation contributed by the sampling variables, the author feels that the results presented are reliable and adequately address the objectives of the study. This was a field study of the operating eleva- tor ecosystem through which a large portion of newly har- vested grain passes in Michigan and many other states. Residual material in this system was shown to be heavily in- fested with several serious pests including the granary weevil. Of the 15 species commonly found in this study, 13 were listed by Ruppel (1976) to be damaging to stored prod- ucts in Michigan. The elevators sampled do not represent a simple random sample of all operating elevators in Michigan, so this dis- cussion is limited to those included in this study. However, the elevators sampled are probably representative of the total population. Samples collected from an individual elevator did represent a simple random sample of sites in that elevator as nearly every accessible site with a consid- erable accumulation (ca. 1 quart) was sampled. Residual grain material located in and around an eleva- tor does not occur in discreet, isolated "sites." It occurs, more or less, in a spatial continuum through the elevator and adjacent area. There are, however, points or sites in this continuum at which considerable accumulations do occur. The rate at which residual material accumulates in any site 126 must be a function of the amount of material moving through that site, the proportion that is left behind, and the rate at which the material is removed from that site. Although no two elevators were exactly alike, there were many similar- ities in their overall construction, and the organization of the machinery and structures used to handle, process, and store the grain. Because of these similarities, there are several sites that are common to many of the elevators. Elevators included in this study varied in size from under 10,000 bushels to over 1 million bushels maximum stor- age capacity. They ranged in age from under 10 years to over 60 years. Many were a composite of older buildings and recently constructed buildings. Some elevators consisted of just one building, others were represented by a complex of several buildings. Sanitation practices varied from manager to manager, some cleaned continuously, others cleaned "only when necessary." All managers reported some past insect problems but nothing regular, and fumigation was the common control practice. Most of the elevators also prepare animal feeds. Residual insect populations in these elevators were shown to be pervasive, although the relatively large stand- ard deviations given for seven species suggests these population to be extremely variable and aggregated in distribution. Variability was statistically shown to be associated with the elevator the samples were collected from for all species tested. Variability in GRWV, RDFB, SWTH, 127 YMWY and BKCB populations was significantly associated with inside and outside collected samples; CRYP, YWMW and BKCB populations with the level inside the elevator; in RDFB, CNFB, YWMW and BKCB populations with the site categories; in CRYP, CNFB, SWTH and YWMW populations with the structural categories. Variation in several species was significantly associated with residual material characteristic: in CNFB and BKCB populations with the amount of material present; in GRWV and SWTH populations with the predbminant grain and beans present in the sample material; in GRWV, YWMW, and BKCB populations with the condition of the residual material. Also, the variability in the number of species present in the samples was significantly associated with the elevator and all parameter categories except the amount of material present at the site. Variability in insect pOpulations associated with eleva- tor might be explained by elevator specific differences in construction, services provided to growers, the major commodities handled and management practices-especially san- itation. Samples collected from elevators 2, 3 and 4 were ' consistently the least infested of the elevators. These elevators are owned by the same company and may share common sanitation practices. Elevators 2 and 3 do not prepare animal feeds as do the others, which might explain the reduced amount of residual material in these elevators. Also, these three elevators are located in an area where large quantities of navy beans are produced and many of the 128 samples collected from these facilities contained a high proportion of this commodity. Navy beans were shown to be least preferred type of residual material for every insect evaluated in this study. The size of the elevator (LCAP) was shown to be weakly associated with several species, i.e., SWTH, BKCB, LBFB, PTND. Because of the weakness of these associations and the association between LCAP and DINC, the observed associations between LCAP and insect density might just be an artifact of sampling and evaluation methods used in this study. Variability associated with inside and outside accumu- lations of residual material is probably the result of the advantages of the protected and sheltered environment inside the elevators. That insects were more common and abundant inside the elevators is important because all the grain is stored inside the elevators in close proximity to residual material. This suggests that sanitation practices should be intensified inside the elevators although outside residual material should not be ignored as a possible source of in- festation. ' That several species were more abundant in basement samples is in partial agreement with results presented by Coombs and Freeman (1955), although the present study suggests a species specific response to the level inside the elevator. That is, some species were more abundant on levels other than the basement. Generally, insects were more common and abundant in basements and extreme upper levels which 129 could reflect differences in sanitation among the levels. These levels are, in a sense, off the beaten path in that most elevator personnel activity occurs on the first or ground floor. Therefore, residual material in the basements and extreme upper levels is more permanent, as these levels may not be included in daily clean-up operations. That feed grinders, leg boots and leg pits are usually located in the basements, might also explain the abundance of insects in basement samples as these sites were often heavily infested. - Variability in insect density associated with the struc- ture of the site might also be explained by sanitation differences among these categories, as sites involving the bases of machinery yielded relatively high densities in several species. Not only because residual material is difficult to clean up from around and under machinery, but because these machines are in constant use and residual material is constantly accumulating around them. This pro- vides a never ending food source for insect populations. However, as the relative frequencies of infestation and mean densities recorded for‘the structural categories points out, any structural type can harbor insects if residual material is present. That the variability in only two species density was associated with the amount of residual material present at the site suggests the relative unimportance of this parameter on the distribution and abundance of insect populations. However, it must be pointed out that, even though there was 130 little difference in the density on a per gram basis among the amount categories, sites having more grams of mater- ial present would no doubt have a larger number of insects present. In some sites there were at least 100 bushels of residual material present, obviously sites such as these pose a tremendous potential for insect production and possible . infestation of stored grain. Although no variability in insect density was signifi- cantly associated with the moisture content of the residual material, generally insects were more common and abundant in dry coded samples. As illustrated in the manager interview sheets, the type of grain and beans present in the sample material corresponds to the grain and beans received by the elevators. Navy bean samples consistently yielded the fewest number of species and individuals of all species, which should not be surprising since the species found in this study prefer farinaceous material (U.S.D.A. 1978). No consistent pattern developed in insect density among the cereal grain categor-‘ ies, in which, according to LeCato (1975), differences in the preference of certain grains among storage species does occur. The predominant grain and beans present in the residual material, no doubt, determines the origin of the grain particulate in the same material. In general, the results .presented for the condition categories in this study are in agreement with those given by Coombs and Freeman (1955), in that samples with a relatively high proportion of whole-seed 131 grain yielded the largest number of insects. However, like differences observed among levels, there appears to be a species-specific response to the condition of the residual material. GRWV was more abundant in samples consisting primarily of whole-seed grains like BKCB was more abundant in samples with whole-seed grains absent. It should not be surprising that, in general, more insects, independent of species, were collected from samples which consisted of a mixture of whole-seed grains, ground grain, dust and chaff since this composition would provide the gambit of food re- quirements for many species. Storage insects were found in samples collected from every site described by the site categories. Common sites that were frequently infested and infested with greater numbers of insects included feed grinders, leg boots, leg pits, beams-planks—ledges, elevated platforms and catwalks, cleaning mills, grain scales and dump pit areas. If nowhere else, these are the sites where sanitation practices can be intensified to reduce residual populations of insects. The variability associated with site categories suggests that site-specific characteristics of residual material influence the distribution and abundance of residual insect populations in the elevator ecosystem. Site-specific characteristics may include the rate and type of residual material accumula- ting in a particular site, sanitation difficulties peculiar to a site and location of that site with respect to inside or outside the elevator or level inside the elevator. 132 Multiple regression analysis and correlations suggest that a small portion of the observed variability in some species densities is associated with the density of the other species present in that same material. However, since no inter-species association was negative, competititon des- cribed by several authors does not appear to be in evidence. Whether or not certain species enhance the distribution and abundance or whether these species are attracted by similar characteristics of the site or residual material was not ascertained by the results of the above analyses. The latter explanation seems more plausible because of the frequency of certain species combinations in samples and the average number of species/sample which suggests species aggregate in those sites providing the most advantageous habitat independ- ent of the species present. CONCLUSIONS Storage insects were shown to be widely distributed in residual grain material in the Operating elevator ecosystem. Variability in the abundance of these species was signifi- cantly associated with the physical characteristics unique to this environment and with the biological characteristics of the residual material including the type of grain and beans present, the condition of the material and the presence of other species in the residual material. Grain is stored in these elevators in a rather open system of silos and bins which are easily accessible to in- sect populations present in residual material. The common presence of serious grain pests such as the granary weevil in residual material which lies in close proximity to the stored grain mass represents a potential threat to grain quality. This threat is not only to the grain that is stored in the elevator, but moreover is a threat to that grain which moves through the other various components of the postharvest grain ecosystem. That is, an infestation originating in the country elevator may be totally overlooked in these facil- ities and unknowingly passed along until a damaging outbreak occurs which requires chemical control. 133 134 The solution is obvious. Sanitation practices must be dramatically intensified in these facilities and not just in specific sites. This study show insect populations can exist wherever residual grain material exists. In the long run, the construction of grain facilities, not just in the elevator system, but in all storage, transportation and processing components must move toward a more closed system. This would not only reduce accessibility by insects, but would also reduce the amount of material which spills from this system thereby reducing residual material and residual insect populations. Country elevators, as mentioned, are the initial, central collection points for much of the grain harvested in this country. There is no reason for these facilities to be the initial, central infestation points of storage insects as well. BIBLIOGRAPHY BIBLIOGRAPHY Adeyemi, S.A.O. 1968. A laboratory study of competition between Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidaé) and three moth species. Bull. Entomol. Res. 58:21-45. Arnett, R. H. 1968. The beetles of the United States. 1112 p. The American Entomol. Inst., Ann Arbor, Michigan. Atwal, A. S. 1974. Ecology of pest complex in stored grains. 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U.S.D.A. 1978. Stored-grain insects. Agricultural Research Service. Agriculture Handbook No. 500. Vick, K. w., w. E. “Burkholder, and J. E. Gorman. 1970. Interspecific response to sex pheromones of Trogoderma species. Ann. Entomol. Soc. Am. 63:379-381. Weygoldt, D. 1969. The biology of pseudoscorpions. Harvard Univ. Press, Cambridge, Massachusetts. QH 301 H3 No. 6. Zuk, P. 1958. Distribution of stored food insects in British Columbia. Proc. Ent. Soc. British Columbia. 55:13-16. APPENDIX A Manager Interview Summaries 142 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 01 & 09 TOTAL ELEVATOR CAPACITY: 130,000 Bushels ELEVATOR DESCRIPTION: Elevator of wooden frame construction sitting on a stone or concrete foundation. Storage facilities include concrete silos, metal "Butler type" bins, wooden bins and a quonset type building which stores mostly corn. GRAINS HANDLED: corn wheat oats soybeans navy beans TEMPERATURE AND MOISTURE CONTROL: The grain is dried, ventilated and turned when necessary. Monitoring is done manually. PAST PEST PROBLEMS: Spotty occurences of weevils and 'brand bug' in wheat and corn. Insect pests also occur regularly in feed supplement bin and quonset hut storage area. PEST CONTROL PRACTICES: Growers with infested grain are requested to treat their grain before bringing it to this facility and when this grain is received it is treated again. Wheat is treated with a grain protectant as it is put into storage. The feed supplement storage bin is cleaned and fogged with a dairy mister yearly. Fumigants are used to spot treat known sites where pests occur. OTHERINFORMATION: This facility grinds more than 100 tons of livestock feed weekly. About 50% of the clientele store and dry their grain on their own farms. 143 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 02 TOTAL ELEVATOR CAPACITY: 500,000 Bushels ELEVATOR DESCRIPTION: This elevator is comprized of several buildings of varying age. The oldest part was constructed around 192“ and the newest part (feed grinding area) was constructed within the past 10 years. All buildings are of wooden frame construction with stone or concrete foundation. GRAINS HANDLED: soybean navy beans corn oats wheat barley TEMPERATURE AND MOISTURE CONTROL: Both are monitored either manually or electronically on a regular basis. SANITATION PRACTICES: Thoroughly cleaned in the spring and on a regular basis throughout the year. PAST PEST PROBLEMS: Some weevil, but spotty. PEST CONTROL PRACTICES: Binned grain is regularly fumigated with Dowfume. OTHER INFORMATION: Modern plant with electronic distribution and monitoring systems. 144 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 05 TOTAL ELEVATOR CAPACITY: 340,000 Bushels ELEVATOR DESCRIPTION: Your basic elevator with wooden frame construction on stone or concrete foundation. Storage facilities include concrete silos and metal "Butler type" bins. GRAINS HANDLED: wheat corn soybean oats TEMPERATURE AND MOISTURE CONTROL: Metal storage bin are equipped with electronic monitoring systems. Other areas are monitored manually or not at all. SANITATION PRACTICES: Plant is swept daily and extensively cleaned monthly. PAST PEST PROBLEMS: Very few, occasionally some brought in by farmed stored grain. PEST CONTROL PRACTICES: Bins are fumigated and treated when empty. OTHER INFORMATION: This plant prepares about 15,000 tons of livestock feed annually. 145 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 06 TOTAL ELEVATOR CAPACITY: 1.1 million bushels ELEVATOR DESCRIPTION: In terms of storage capacity, this elevator is the largest in Michigan. Storage facilities include large concrete silos and metal "Butler type" bins. GRAINS HANDLED: corn wheat oats soybeans TEMPERATURE AND MOISTURE CONTROL: Stored grain is constantly monitored and turned if heating occurs. SANITATION PRACTICES: Plant is thoroughly cleaned in the Spring and cleaned during the year. PAST PEST PROBLEMS: Some weevil problems, mostly in wheat. PEST CONTROL PRACTICES: Incoming grain is monitored closely for insects. fumigated when infested. OTHER INFORMATION: and dried constantly Grain is Plant prepares about 15,000 tons of livestock feed annually. 146 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 07 TOTAL ELEVATOR CAPACITY: 500,000 Bushels ELEVATOR DESCRIPTION: Modern concrete facility with feed grinding building separate from grain processing area. Some older buildings also present but most of these are out of service. GRAINS HANDLED: corn wheat soybeans oats rye some navy beans TEMPERATURE AND MOISTURE CONTROL: Grain is dried to about 15% moisture before it is stored. Temperature is monitored manually at regular intervals. SANITATION PRACTICES: Plant is continually cleaned. PAST PEST PROBLEMS: Some pest problems but nothing serious. PEST CONTROL PRACTICES: Grain is fumigated when found to be infested. OTHER INFORMATION: This plant prepares 30 - 50 tons of livestock per week. 147 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 08 TOTAL ELEVATOR CAPACITY: 100,000 Bushels ELEVATOR DESCRIPTION: Facility is quite old and poorly maintained. The main grain processing building in built on stilts under which large accumulations of whole grain were found. Storage facilities include steel "Butler type" bins and wooden bins inside the elevator. ' GRAINS HANDLED: wheat corn oats soybeans TEMPERATURE AND MOISTURE CONTROL: Grain is dried before it is put in storage but it is not monitored in any way while it is in storage. SANITATION PRACTICES: Plant is cleaned daily. PAST PEST PROBLEMS: Pest problems were described as "seldom". PEST CONTROL PRACTICES: None offered. OTHER INFORMATION: Plant prepares about 100 tons of livestock weekly. 148 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 10 TOTAL ELEVATOR CAPACITY: 10,000 Bushels ELEVATOR DESCRIPTION: Facility is constructed entirely of wood and sheet metal. All storage is in wooden bins located in the only grain processing building. GRAINS HANDLED: wheat corn TEMPERATURE AND MOISTURE CONTROL: None SANITATION PRACTICES: Continually cleaned. PAST PEST PROBLEMS: No insects problems, but some rodent problems. PEST CONTROL PRACTICES: None OTHER INFORMATION: None 149 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 11 TOTAL ELEVATOR CAPACITY: 60,000 Bushels ELEVATOR DESCRIPTION: Newly constructed. Wooden frame construction on a concrete foundation. Storage includes steel "Butler type" bins. Facility mainly a feed grinding plant. GRAINS HANDLED: corn wheat TEMPERATURE AND MOISTURE CONTROL: Grain is ventilated during storage period. SANITATION PRACTICES: Weekly cleaning. PAST PEST PROBLEMS: Some weevil problems. PEST CONTROL PRACTICES: Fumigants used when problems occur. OTHER INFORMATION: Plant prepares about 100 tons of feed weekly. 150 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 12 TOTAL ELEVATOR CAPACITY: 10,000 Bushels ELEVATOR DESCRIPTION: Facility is very old and dilapidated. Constructed wood and sheet metal with a stone and concrete foundation. GRAINS HANDLED: corn wheat oats rye TEMPERATURE AND MOISTURE CONTROL: Grain temperature monitored manually. Facility has no dryer. SANITATION PRACTICES: No regular cleaning schedule or practice. PAST PEST PROBLEMS: Some weevil problems in stored wheat. PEST CONTROL PRACTICES: Fumigants used when problems are noticed. OTHER INFORMATION: None offered. 151 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 13 TOTAL ELEVATOR CAPACITY: 1 million bushels ELEVATOR DESCRIPTION: A very large grain processing complex consisting of several separate plants which are specialized in the type of grains handled in them. Storage facilities include large concrete silos, wooden bins and large "Butler type" metal bins. GRAINS HANDLED: corn wheat oats soybeans TEMPERATURE AND MOISTURE CONTROL: Grain is dried to 15% moisture and manually monitored weekly while in storage. SANITATION PRACTICES: Plant is cleaned on a weekly schedule. PAST PEST PROBLEMS: Some weevil problems and meal moth problems in the feed plant. ‘ PEST CONTROL PRACTICES: Fumigants used for weevils and sprays of malathion used against meal moth. OTHER INFORMATION: Plant prepares about 45,000 tons of livestock feed annually. 152 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 1A TOTAL ELEVATOR CAPACITY: 100,000 Bushels ELEVATOR DESCRIPTION: Facility of wooden frame construction on a stone and concrete foundation. Storage facilities include concrete silos, metal "Butler type" bins and wooden bins. GRAINS HANDLED: wheat oats corn TEMPERATURE AND MOISTURE CONTROL: Grain is dried to 1A - 15% moisture. Grain is monitored manually on a somewhat irregular schedule. SANITATION PRACTICES: Continually cleaned. PAST PEST PROBLEMS: Some weevil problems. PEST CONTROL PRACTICES: Fumigation. OTHER INFORMATION: None offered. 153 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 15 TOTAL ELEVATOR CAPACITY: 10,000 Bushels ELEVATOR DESCRIPTION: Possibly the oldest elevator in Michigan. Constructed entirely of wood. Storage facilities consist only of wooden bins. GRAINS HANDLED: corn wheat oats soybeans TEMPERATURE AND MOISTURE CONTROL: Grain dried to 14 - 15% moisture content and manually monitored while in storage. SANITATION PRACTICES: Some cleaning done daily. PAST PEST PROBLEMS: Described as "some". PEST CONTROL PRACTICES: Bins are treated when empty. Fumigants are used when problem occurs. OTHER INFORMATION: None offered. 154 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 16 TOTAL ELEVATOR CAPACITY: 3O - 40,000 Bushels ELEVATOR DESCRIPTION: Plant of wooden frame construction on a stone or concrete foundation. Storage facilities include concrete silos, metal "Butler type" bins. GRAINS HANDLED: wheat corn oats soybeans TEMPERATURE AND MOISTURE CONTROL: Grain is dried to about 15% moisture content and manually monitored throughout the storage period. SANITATION PRACTICES: Plant is continually cleaned. PAST PEST PROBLEMS: Described as "some". PEST CONTROL PRACTICES: Incoming grain is constantly monitored. Fumigants are used when problems occur. OTHER INFORMATTION: None offered. 155 MANAGER INTERVIEW SUMMARY ELEVATOR CODE: 17 TOTAL ELEVATOR CAPACITY: 175-200,000 Bushels ELEVATOR DESCRIPTION: The main building is of wooden frame construction sitting on a concrete foundation. Storage facilities include concrete silos, metal "Butler type" bins and wooden bins. GRAINS HANDLED: corn wheat oats rye soybeans navy beans buckwheat barley TEMPERATURE AND MOISTURE CONTROL: Grain is dried to about 15% moisture content and electronically monitored every week. SANITATION PRACTICES: Plant is cleaned at least once a month. PAST PEST PROBLEMS: None. A PEST CONTROL PRACTICES: Empty bins are fumigated before grain is stored in them. OTHER INFORMATION: None offered. 156 MANAGER INTERVIEW SUMMARY ELEVATOR CODE : 18 TOTAL ELEVATOR CAPACITY: 130,000 Bushels ELEVATOR DESCRIPTION: Plant is entirely of wooden frame construction and storage is in wooden bins only. GRAINS HANDLED corn wheat oats soybeans navy beans TEMPERATURE AND MOISTURE CONTROL: Grain is dried to about 15% moisture content and manually monitored during the storage period. SANITATION PRACTICES: Plant is continually cleaned. PAST PEST PROBLEMS: No insect problems in last two years. PEST CONTROL PRACTICES: Empty bins are thoroughly cleaned and treated with malathion and methoxychlor. OTHER INFORMATION: Plant prepares 80 tons of livestock feed per week. APPENDIX B Listing of Raw Data 157 F o o o o o o F o N o o o o o mm moF m cm ._F m N o: F F ON mm m FmF N o o o o o o o o o o o o o o o mm :Na N N F m N FF F F aF mm m FoF N F o o o o o o m o o o o o o o mm FFF N o F N N m: F F mF mm m FmF N o o o o o o o mN o c c o c o 0 mm mNN m e F N N o: 2 F FF mm m FmF N o o o o o o F m o o o o o o 2 mm moo m osN F m m m: F F 0F mm m hmF N o o c o o o o o o o o o o o 0 mm mam m o F 2 m am N F mF mm m FQF N o o o o o o F Fa o o o o o o 0 mm ma: N m F N m m: N F 3F mm m hmF N o o o o o o o N o o o o c o 0 mm ON: m c F m 2m 0N F F mF mm m FmF N o o o o o o o o o c o o o o 0 mm 2mm m c F N m :m F F NF mm m FQF N o o o o o o o am o o o o o o 0 mm Fem m o F m N am o F FF mm m FmF N o o o m o o F N: o o o o o 0 >0 mm pom N N F N m m: o F cF mm m FwF N o o o F o o o F o o o o o 0 Fa mm FmN N om F m N :m o F a mm m bmF N o o o o o o o o o o o o o c o om wNN N o F N m N: N F m mm m FQF N o o o o o o o F o o o o o o o am so: m o F m N :m o F F mm m FNF N o o o o o o o NF 0 o o o o o 0 mm :mo m o F m m am F F 0 mm m FmF N o o o o o o o o o o o o o o 0 mm arm F m F F m cm N F m mm m FmF N o o o o o o o m o o o o o o 0 mm moF F o F F m MN N F : mm m FQF N o o o o o o o m o o o o o o 6 mm :NN : o F N : 9N F F m mm m FmF N o o o o o o o NF 6 o o o o o o mm NN: N o F N m am F F N mm m FQF N o o o o o o o F o o o o o o 0 mm NmF : o F N m F: F F F mm m FQF N om a: as am on ma <0 mm an 3» 3m 20 a: mo 20 Ha m3 no cm oz 2< an em >4 OH 2m 04 >m an m< .ozom mo .oz .om "92mmma mmFquo .ezmmmea mmaHznp .9: “zen: mo .oz .nz “azaa mo .oz .ea "mmon mo .02 .oa “mama mo .02 .m4 Negev me .o: .«o “moem ac .02 .um "saga mo .oz .ea "szzy mo .02 .3» “mama mo .0: .3m “maze no .oz .20 image mo .02 .me “memo no .02 .mo “>3mu mo .oz .eo “maan 2H ooHemm onaameozH .Ho umxcmo 2H mumzem mo amon: .m: “mace oneHazoo .ao “mace zHamo szaszoamea .oa "moon meaamHox .oz "moon azaoza .ze “maou meaaoamem .mm "moon meHm .am "mace gm>ms .>a “moon sac eo 2H .0H w.oz mumzam .zm neo9<>mam mo aaHoemeo zeszmam .>m “zoueomgaoo no mean zquae .ae inseam was ac «med .m¢ ”sue emcee: .mme mmxz=m .mmoec>mqm 02Hh°r~~o¢z~~o rm:-[~00mmcomahpzoooPommmaomov-Noor- NPm ma'PNPNNNNNOPNPNSPmaa'msam QPFNabthahmhzfiN-‘JRSNPSNNNNNNP OMPOOPNFNMONOOOFOOONNONhNh-NFN c-r- N m:- r-N NPN F c-u—Nr-v-r-PNNNNNNv-Pv-v-v— Pf-F-I-I- Pc—v-v- aamFNmzmma-mmmmmma-mmzNNNMNNmaa Nv-c—zrma'mzru—Pv-q—PmmsN3Nmmmmmm=rmmm m N m :mh-momma-v-xome-tsomr-rPazmmomnmwazm m Nlnv- mmma-Nm Pmmmzmmm Pv-q-v-c—v-v-Pv-v-v-c-q-v—Pv-v-c—v-Pv-NMMPF'v-v— NNI—PNPNNNNNNPFPPPPPPPPFFF’PFP PNMRmVDFQOOPNma'mQFQO‘OF-ma’mOhQO‘ PPPPFPPPPPNNNNNNNNN OOOOOOOOOOOOOOOOO COCO OOOOC mmmmmmmmmmmmmmmmmmmmmmmmmmmm \oaoaoaoaoaocoaoaoaoaoaoaoaoaoaoaoaoaoooaoaoaoaocomaoaoao q-v-«I-PFNv-Pq—q—v-q-i-Pq-v—v-c-v-r-Pv-I-q-v-v-c-v— OOOOCOOOOOOOOOOOOOOOOOOOOOOO NNNNNNNNNNNNNNNNNNNNNNNNNNNN mmmmmmmmmmmmmmmmmmmmmmmmmmmm COOOOOOOOOOOOOOOCCOOOOOOOOOOO OOOONONOPPOOOOOOmF-fi'mmcov—COOOO O F O O O OF O F O O O O OF FO FMN N N ..F N m am F F mN Fm O NON m O O O O O NF O NO O O O F O FO NO: F NN F m am ON F F :N Fm O NON m O O O O O O O O O O O O O FO ONN : a F N m Om F F MN Fm O NON m O O O O. O F O O O O O O O FO NOF 2 O N N m Om F F NN Fm O NON m O O O O O O O O O O O O O FO FOF : O F N m O: F F FN Fm O NON m O O O O O ON O O O O O O O FO FN : O F F O OO F F ON Fm O NON m O O O O O OFF O NO O O O O O FO mON O O F N m O: O F OF Fm O NON m O O O O N ONF O OO O O O m Fm FO OOm O F F m m om m F OF Fm O NON m O O O O O O:F O OF O O : N : FO omm O O F m m OO O F NF Fm O NON m O O O O O mm O O: O O O O O FO FFm m F F m :m ON m F OF Fm O NON m O O O O O FOO O O O O N O F FO FO: m mF F O m :m N F mF Fm O NON m O O O O O OOF O O O O O O FF FO NNN m MNF F N am O: N F :F Fm O NON m O O O O O :m O mm O O O O O FO FNm m F F m m O: N F mF Fm O NON m O O O O ON ONN O OF O O O O N FO OmF m F F F m Om N F NF Fm O NON m O O O O F NN O F O O O O N FO OmF m F F F m Om N F NF Fm O NON m O O O O O O O O O O O O m FO NFm m m F s N am O F FF Fm O NON m O O O O N F O O FN NN O FNN m:F FO OO2 m mF F m :N Om O F OF Fm O NON m O O O O N O O a O MOF O O: F: OO Omm m mF F 2 N mm O F O Fm O NON m O F O O F NF O O O N O OF mg: OO Omm N :mN F a N mm O F O Fm O NON m O O O O O m O FF O NOF O NN OO OO NOm N F . F O :N NN O F N Fm O NON m O O O O N NF O FF O mNF N O NNm OO :NN N F F O F O F N O Fm O NON m O O O O O N O O O O O F O OO NON N F F N z ON F F m Fm O NON m O O N O O FN O m O O O O NF OO 20: N F F N m zm F F 3 Fm O NON m O O O O N OOF O N O 2 ON m mO OO mFO N a F N am am F F m Fm O NON m O O O O O MN O O O O O O O OO OON N F F N am ON F F N Fm O NON m O O O O O N O O O O O O O OO OOF N NO F m m 2m F F mm OO O FON m O O O O O OO O N O O O O O OO OON N NO F N m OF F F Nm OO O FON m O O O O F sz O O O O O O F OO OFm N NNF F m zm :N N F Fm OO O FON m O O O O O O O O O F O N Nm OO :Om N F N m N am O F Om om O FON M O: HO OO OJ <0 mm MO 3N 3m 20 OO NO NO HO O: OO ON or :4 am am >4 OH 2m 04 >O OO :4 .OOOZHNZOO .Fm wands 1 1 1 9 0 0 0 0 0 0 49 0 0 0 0 0 0 0 4 4 0 0 0 0 0 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 21 7 0 0 21 21 2 0 SH YH DK BK CA LB DO PT MD MT SC 2 RD CN 0 201 0 123 0 156 0 2 0 0 0 8 0 1 0 17 0 0 3 518 146 6 2 441 61 237 2 467 61 2 2 271 61 133 61 16 3 399 61 12 2 459 61 27 2 336 61 267 2 543 61 12 7 1 1 1 1 1 1 52 2 4 8 2 2 2 0 34 2 4 0 34 2 4 0 37 24 4 1 1 1 1 1 CONTINUED. 3 202 9 51 33 1 3 202 9 51 27 1 3 202 9 51 28 1 3 202 9 51 29 1 3 202 9 51 30 2 3 202 9 51 31 1 3 202 9 51 32 1 3 202 9 51 26 1 AR JD EV LC SN IO LV ST SR AM M0 PO CD HS DI GR CP TABLE B1. 163 COOOOOOOOOOOOOOOOONO OOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOO 00000000000000000000 00000000000000000000 OOOOOOOOOOOOOOOOOOOC OOOOOOOOMCOOCOOOOOOO PONQSOOOOOOOOOOMOSLOO \ocn .. O COCO O CO C OSQNOOOOOPO 0 COD 0 (“\DN OOOOOOOOOOOOFOOdba’m a- N‘h—U\ P OOOOOOOOOOOOOOOCOO OCOOOOOOOOOOOOOOOO P 000003200000000000 POOOOOOOOSOOOOOOOOOO PPFPPPPFq—Pfiafizsamam \OOOOOOOOOOOOOO‘OOOQQ OmfiNmsmb-QQNPRLOMIDO‘MQ OONPMNOOO-fi’NF-OMLDO‘MPO PMPNPNPON mONNQ \OMM Pagahahmm-fi'Pv-NNPPNNN NPOONOPPPFPPPMOOQON '- menO M PPFPNPNNNv—v—v—FPPPPFP MRMMMNNm3-‘33NQMNNNMM2 MMSMMN-fi'PNNNmav-MMSMMLh m m Q033NQ=PNNmNFN33023® MINM: N mmmNm MMNMMP NNNNMPNPI—PPPOPPFPPPP FFPPPNPNPPPFPNPPv—v—PP fimxob-QO‘OPNM-fi’ NM:Lfi~OP¢DO\ MMMMMMZ'Rfifi: PPPPPu—u—Pv—Pv-b-hblsb-fihb-F mmmmmmmmmmmmmm mmmm O‘O‘O‘O‘O‘O‘O‘O‘O‘O‘O‘NNNNNNNNN NNNNNNNNNNNQQQQQQQQQ OOOOOOOOOOOQQQQQQQQCD NNNNNNNNNNNPPPFPPFPP MMMMMMMMMMMNNNNNNNNN 18 0 0 0 0 0 0 0 0 29 26 34 4 1 0 3 257 61 0 0 1 2 188 2 57 10 1 1 5 0 0 0 0 0 0 0 0 0 0 O 0 0 0 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 14 0 0 0 O O 0 0 13 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 43 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 SH YN DK BK CA LB DG PT MD MT SC 0 RD CN 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 u 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 14 0 46 61 109 61 80 61 309 61 117 61 0 3 276 61 6 2 231 61 6 2 404 61 0 3 332 61 89 61 175 61 152 61 0 6 0 4 6 2 0 4 212 61 6 2 560 61 6 1 453 61 37 3 210 61 8 3 213 61 0 7 3 4 3 4 8 1 3 2 1 2 276 61 13 2 270 61 0 4 23 2 320 61 1 1 1 1 1 1 1 1 1 1 1 3 NfiNNm MMMMN 2 3 1:32 431 200:2:- 24 2 3 3n 2 2!: 112 3332 34 32 3723 11 31122 11.110 22 1 1 1 1 1 2 38 3 1 3 3 2 1 2 3 1 3 0 3 2 O u 5 CONTINUED. 2 188 2 57 11 1 2 188 2 57 12 1 2 188 2 57 13 1 2 188 2 57 14 2 2 188 2 57 15 1 2 188 2 57 16 1 2 188 2 57 17 1 2 188 2 57 18 1 2 188 2 57 19 1 2 188 2 57 20 1 2 188 2 57 21 1 2 188 2 57 22 1 2 188 2 57 23 1 2 188 2 57 2 1 2 2 7 2 1 2 2 188 2 57 26 1 2 188 2 57 27 1 2 188 2 57 28 1 2 188 2 57 29 1 2 188 AR JD EV LC SN IO LV ST SR AM M0 PC CD NS DI GR CP TABLE B1. 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 21 0 0 0 0 0 0 0 49 0 O 0 0 0 0 0 0 0 0 0 15 0 161 0 0 0 0 0 0 0 129 61 151 61 1 4 268 61 1 1 1 0 4 1 0 4 2 1 4 2 4 2 n 4 5 2 1 48 2 2 1 2 33 1 2 188 2 57 34 1 2 188 2 57 35 1 2 188 2 57 36 2 2 188 2 57 37 2 mm N-b-r- U\U\U\ NNNN 57 30 1 8 QQCD mama 2 1 2 1 2 1 2 1 9 0 0 0 0 0 0 0 38 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 82 56 37 61 0 3 289 61 99 61 207 61 0 7 289 56 1 16 1 O 7 1 1 1 1 1. 1 34 2 1 1 34 2 1 1 4 24 4 1 1 1 3 1 4 50 3 2 1 1 7 57 1 2 7 57 2 1 3 201 3 201 CONTINUED. TABLE B1. SN YN DK BK CA LB DG PT MD MT SC RD CN AR JD EV LC SN IO LV ST SR AM M0 PC CD NS DI GR CP ‘0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 49 56 176 56 1 7 288 56 1 1 2 1 1 3 2 4 2 2 2 53 2 1 3 11 1 1 1 PNN m=rm (NF-N mmm b—b—t~ PPP COO NNN mmm 0 0 0 0 0 0 0 0 0 0 0 118 56 0 7 1 7 57 6 2 7 7 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 3 201 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 3 2 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 1 o o n 311 7 O 38 0 0 0 22 56 0 23 56 O 112 56 0 237 2 221 56 87 25 3 7 215 56 O 0 7 0 5 0 4 1 2 1 2 1 1 1 48 23 4 1 7 57 11 2 1 7 13 3 2 7 57 7 57 10 1 0 0 0 0 0 0 O 0 14 0 2 0 0 0 0 0 0 0 0 0 173 56 1 2 488 56 7 13 3 2 23 7 2 25 24 4 1 1 7 57 12 2 165 2 0 0 0 139 0 1 7 57 13 1 0 0 0 0 0 0 0 0 74 0 0 0 0 0 0 0 0 179 56 3 7 0 4 1 2 7 57 14 2 1 0 0 0 0 0 0 0 155 0 0 0 0 0 0 0 0 0 0 0 0 160 56 158 56 237 2 395 56 558 PO 7 57 15 1 7 57 16 1 1 a. 0 1 0 37 5 4 7 57 17 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 1 21 0 23 2 231 56 267 3 34 7 57 18 1 0 0 101 712 56 2 2 440 56 2 1 1 24 4 2 1 25 4 3 1 48 1 1 7 57 19 1 15 0 0 0 0 0 0 0 11 11 1 1 1 1 1 7 57 20 1 0 0 0 0 0 0 2 0 0 0 0 0 0 1 3 1 0 1 0 O 4 2 390 56 366 23 2 486 56 23 2 208 56 237 2 333 56 237 2 537 56 u 1 7 57 21 1 12 58 13 91 1952 119211 7 57 22 1 3 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 7 57 23 1 0 0 0 O 0 0 90 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13 0 0 0 1 0 0 0 0 0 u 42 7 2 396 56 12 3 255 56 23 7 245 56 PFPN 7 57 24 1 1 7 1 7 2 7 1 7 1 3 201 3 201 3 201 3 201 3 201 188 56 0 0 4 23 7 1 1 1 7 2 8 2 3 2 56 2 3 1 1 7 57 29 2 3 201 3 201 3 201 0 0 0 0 0 0 0 0 O 0 159 56 23 2 289 57 7 57 30 2 2 2 0 0 0 0 0 0 0 0 1 7 57 32 1 1 0 00 00 000 00 00 000 0 00 00 000 0 5 00 00 000 8 10 00 000 00 00 000 00 00 000 0 00 00 000 0 0 00 OJ 000 1 B 04 00 00 00 0 0680 0240 omu1 0 0 SH Y" DK BK CA LB DG PT MD MT SC 0250 0 0 0 0 w W 0 0 O 0 W 0 0 0 0 0 0 0 0 0 583 57 404 57 123 2 338 57 12 2 406 57 127 2 361 57 449 57 303 57 12 7 235 57 123 7 423 57 0 7 264 57 181 181 1 1 1 2 8 11 1 1 W 242 1 1 CONTINUED. 03724 0 7W422 7W412 32m AR JD EV LC SN IO LV ST SR AM M0 PO CD HS DI GR CP H&EM. 166 000000 000P00 000000 000000 000000 N 000000 00000" 0000l~0 mr- 0 00'- 0 P0 00 00 00 00 00 00 0PM 00 F 000000 [s b00000 mmmmmm N-fi’v’a’00 NmmcnOm 05001-03 MNMF8N 0001-0110 N '- u-c-r-Nt-v- mmmO (“PM FPPF N0 5 2 1 1 757W1 7W511 mmzrnO-mmmmm: NMNN ('13!- m .31-fit~ MN Pv-N NM: mmm NNN mmm NNN 3 201 3 201 32m PN000v-v-PP0P00 0000000000000 0000000000000 002000000N1~P0 P 0000000000000 0000000000000 0000000000000 0NMOOMRON000P m mun-v- m 00000P00 00 0P0 003' ov-v- N v- m 1— '- N000000000000 0000000000000 0000000000000 P300000000000 151—00200003001— N0 '- 0000000000000 mmmmmmmmmOOOO NmNMNMO‘m003mm 0:00NMN031—NO‘0 NMNMNMMM c-v- N NNMMNMMMFCSU‘N MMNPPMNP0M000 v-P FFNPPPFPPPPPF mmmmzmv—me memmmmzwm hfla'fl'Cfl’RFl‘P mmmmmmm 1" FOFPP’FFPF NNNNNNOOOO 2:: NNNNNNOOOO v-v-c—v— v-v-v-I—v-F-[Nhfih 0000000000 NNNNNNNNNN mmmmmmPv-v-v— 167 P0P000OOOOOOOOOOMOPOOOPNOONO0 0 fl) 00000000000000000000000000000 00000000000000301.0000000000000 00000000F00P00000000000F00000 N: F Ln \0 20QEOMO00M0000N0F00 Q'- Om N mommo :rN '- MOF 00000000000000000000000000000 m 00000000000000000000000000000 00N00P00m0P000=me000000000000 N O: NO OO O4 <0 mm N CNN \0 In N0000000P0000"00000000000000 mm m FOOmOPooz‘OOMOF-NNCOQOOOPMOOO'- M : 000P0F¢DP00000000N00000 \O N \OP000©NF0000P0200000000000000 0000000000000000000000000000" 0000FU‘0000M0000‘00MU‘1000000(“v-011‘ P O'- P P 0 :OmNNQQPPOOOOOOV-‘OO P v- 1— \O \O P O‘ ‘— FO OF FO MNON FO O FO FO ONM FO OFF FO NNM FO F: OO M OO OO OO P N \0 MO 3» 3m 20 O: NO NO HO .MOM Om: FN: ONN OMM FON NOF MNN om: OO ONF Om: NON NMO OO: N:O MON OMN :OM O:: ONN OF :MF ONF :FF FOF :OM ::N MNN O3 O0 NamPNNPLOPPMFMMMMNNPMU‘MMfiMMNPM 5'oza'mwv-omav-NOPPMMv—MOOMQQv-c—v-mq- P P P PN N F m : N F M N N F F : F N N F F : N N N F N F F N N N N N F N MN ON 0: IO :N OM O F O O: FF NON F :N NN O F N O: FF NON F :N NN F F O O: FF NON F N O F N O O: FF NON F :N FM F F : O: FF NON F :N ON F F M O: FF NON F N :M F F N O: FF NON F N :M F F F O: FF NON F F N F N ON O: OF NON F N N F N :N O: OF NON F F N F N MN O: OF NON F N FF F N NN O: OF NON F F O F N FN O: OF NON F M OM O F ON O: OF NON F :M OM O F OF O: OF NON F M :M F F OF O: OF NON F M :O F F NF O: OF NON F N :M O F OF O: OF NON F M N: : F OF O: OF NON F M N: M F :F O: OF NON F M OM N F MF O: OF NON F M OM F F NF O: OF NON F M :M F F FF O: OF NON F M :M F F OF O: OF NON F M NM F F O O: OF NON F :M ON F F O O: OF NON F N :O F F N O: OF NON F F O F N O O: OF NON F N FF F N O O: OF NON F Om NO >4 OH 2O 04 >O Oh O4 .OOOZHHZOO .FO OOO4 OH 2m 04 >O OO O< .OOOZHNZOO .FO OOO4 OH 2m O4 .OMOZHNZOO :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN :F :FN MF MFN MF MFN MF MFN mF MFN MF MFN I\O\O\O0000000000000000000000000\O >m OO Md .FO O404 OH 20 04 >0 OO O4 .OOOZHN200 .FO O404 OH 20 04 >O ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN 3:222:323223233322033323332333 OO m d .OOOzHNzoo .FO O404 OH 20 04 >0 ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN ONN 333323333232333233’33333333232 OO m d .OOOZHNzOO .FO O404 OH 20 04 >0 OO O< .OOOzHNzOO .FO O400 FNN FNN FNN FNN FNN FNN FNN FNN FNN FNN FNN FNN FNN FNN FNN OO ::::::::::::::: m 0 NF F N N NO F F ON FO F F F N :M F F NN FO F F F N OO F F ON FO O N : N : F N :N FO O N : N O F N MN FO O N N MN OF F N NN FO M N M N : F N FN FO O N M N O F N ON FO N F N : NN O F OF FO MN F : N :M O F OF FO MN F : :N NN O F NF FO F F N N O: O F OF FO O F N : O: F F OF FO MNF F N M :M N F :F FO O F N M OM N F MF FO 0O 0! :1 O0 NO >4 OH 20 04 .OOOZHNOOO .FO O40