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Each original is also photographed in one exposure and is included in reduced form at the back o f the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 BIOLOGY AND PEST STATUS OF LESSER APPLEW ORM GRAPHOLITA PRUN1VORA (W ALSH) (LEPID OPTERA : TORTRICIDAE) IN M ICHIGAN By Grzegorz Krawczyk A DISSERTATION Submitted to M ichigan State University in partial fulfillm ent o f the requirements for the degree o f DOCTOR OF PHILOSOPHY Departm ent o f Entomology 1996 UMI Number: 9631296 UMI Microform 9631296 Copyright 1996, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ABSTRACT B IOLOGY AND PEST STATUS OF LESSER APPLEW ORM GRAPHOUTA P RIJN IVOR A (W ALSH) (LEPID OPTERA : TORTRICIDAE) IN M ICHIGAN By Grzegorz Krawczyk Lesser appleworm GrapholUaprunivora (W alsh) (Lepidoptera : Tortricidae) larvae are internal fruit feeders. As a polyphagous species it feeds on numerous plant hosts, including most cultivated pom e and stone fruits that are grown in northern United States. Studies about biology, seasonality, flight bionomics, and pest status o f G. prunivora were conducted in commercial and abandoned apple orchards located in four different fruit grow ing regions o f w est Michigan during 1991 - 1994. Larval and pupal stages characters and fruit injury characteristic were compared to three other closely related fruit feeders: codling moth Cydiapomonella (L), oriental fruit moth G. m o ksta (Busck), and cherry fruitworm G. packardi Zeller. Insects collected from injured apple fruits w ere used for laboratory observations. In M ichigan weather conditions, lesser appleworm typically has two generation per year, with the first generation adult flight starting in the middle o f May and the second generation being present in orchards until late September. All m ajor insect life events were described using degree day accumulations at bases o f 42° F and 50° F. Six pherom one traps designs were compared for effectiveness in insect monitoring. The Pherocon II trap design captured the highest num ber o f lesser appleworm males. These traps captured also four other moth species. Lesser appleworm larvae were never found in fruits collected in com m ercially managed orchards, even when adults moths were present in the pherom one traps in the orchards during the season. In abandoned orchards lesser appleworm injured up to 7 percent o f fruits. Eighty nine percent o f samples collected during the season had infestations lower than 3 percent. An oviposition preference study showed that lesser appleworm females will accept cultivated plant hosts as well as wild ones. A com parative study o f pupal length and width o f m esowing and anal segm ent allowed for reliable pupa identification. Differences in the num ber o f crochets on larval prolegs and the structure o f anal comb allowed for separation o f lesser appleworm larvae from those o f oriental fruit moth, but was not reliable for separation o f lesser appleworm and cherry fruitworm larvae. To my wife Teresa, without whose understanding, patience and support none o f it would have been possible. To my parents, who believed in and understood the importance o f education. To M agdalena and Joanna for just being here. ACKNOW LEDGM ENTS I am grateful to Dr. James W. Johnson, my m ajor advisor, for making it possible for me to be a part o f his research program and pursue graduate studies in entomology. His support and encouragem ent throughout the whole process w ere essential in com pleting this research. 1 also wish to thank the members o f my guidance committee: Dr. Karen Klomparens, Dr. Larry Olsen, Dr. Dave Smitley, and Dr. Fred Stehr for guidance throughout my program and for the critical review o f manuscripts. Special thanks to the following fruit growers for allowing me to conduct experim ents on their property: Crane family (Fennville), Hershey family (Casnovia), Van der Zanden family (Casnovia), Burm eister family (Shelby), and M orrison family (Paw Paw). The work would not have been completed without the help o f great people from Trevor Nichols Experim ental Station: M att Daly, Janis Howard, D oug Kronemayer, W ayne M cFarland and numerous summ er students workers. Very special thanks to John W ise for his friendly support during my whole research program and his patience in introducing me into the M ichigan fruit system. I also w ant to say “Thank You” to a num ber o f people that I have m eet and had the honor to work with during my student and professional times in Poland, w ithout whose help and support I would never have had this great opportunity to com plete my graduate program in the Department o f Entomology at Michigan State University. TABLE O F CONTENTS LIST OF TABLES LIST OF FIGURES v . . . . . . . . viii CH APTER 1. Introduction to lesser appleworm Grapholitaprunivora (W alsh) (Lepidoptera : Tortricidae) in North America. Introduction . . . . . . . Scientific and common names o f G. prunivora Geographical distribution . . . . . . . . 1 1 . 3 . 4 Main hosts . . . . . . . . 4 Life stages . . . . . . . . 5 Life history . . . . . . . . 8 Pest status . . . . . . . . 9 Natural enemies 11 Sex pheromones 11 References 14 CH A PTER 2. Pest status o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in M ichigan apple orchards. A bstract Introduction 21 21 . . M aterials and M ethods . . . . . vii . . . . . . 22 23 Results and Discussion Reference Cited 26 . . . . . . . CH A PTER 3. Seasonality o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in Michigan apple orchards. Introduction 35 37 37 M aterials and M ethods . . . . . . 40 Results and Discussion . . . . . . 43 . . . 54 Reference Cited . . . . CH A PTER 4. Trap efficacy and flight bionomics o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in Michigan. . . . . . . . Introduction . . . . M aterials and M ethods . . . . . . . . 57 . 57 . 59 Results and Discussion 61 Reference Cited 71 CH A PTER 5. Lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera: Tortricidae) oviposition preference and female fecundity when reared in laboratory. . . . . . . Introduction . . . . . . . 74 . 74 M aterials and M ethods . . . . . . 75 Results and Discussion . . . . . . 79 . . . 87 Reference Cited . . . viii . C H APTER 6. Larval and pupal characters for identification o f lesser appleworm Grapholita prunivora (W alsh), oriental fruit moth G. mo/esta (Busck), and cherry fruitworm G. packardi Zeller (Lepidoptera : Tortricidae). . . . . . . 89 Introduction . . . . . . . . M aterials and M ethods Results and Discussion 89 91 . . . . Reference Cited . 94 115 A PPEN DIX 1. Record o f deposition o f voucher specim ens. i.\ 117 L IST O F TA B LES C hapter 2. Pest status o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in Michigan apple orchards. Table 1. Table 2. Table 3. Chapter 3. Two way analysis o f variance (ANOVA) o f lesser appleworm fruit infestation in four abandoned apple orchards in Michigan. 29 Mean fruit infestation by four internal fruit feeders: lesser appleworm (LAW), oriental fruit moth (OFM), codling moth (CM), and cherry fruitworm (CFW ) in four abandoned Michigan apple orchards during 1993 and 1994. . . . . . 30 Frequency analysis o f fruit infestation by lesser appleworm (LAW ) in four Michigan abandoned apple orchards analyzed for normality o f distribution by K olm ogorow - Smirnow test. . 31 Seasonality o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in M ichigan apple orchards. Table 1. Table 2. Table 3. Lesser appleworm life events in com parison with accumulation o f degree days base 42° F and 50° F 46 Lesser appleworm degree days base 42° F and 50° F accumulation in relation to previous event 48 Capture o f different moths by sex pherom one traps o f three internal fruit feeding tortricids 50 X Chapter 4 Trap efficacy and flight bionomics o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in Michigan. Table 1. Chapter 5. 68 Lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera: Tortricidae) oviposition preference and female fecundity when reared in laboratory. Table 1. Table 2. Table 3. C hapter 6. Comparison o f six pheromone trap designs for capturing males o f lesser appleworm. Data collected in Douglas, MI abandoned orchard during 1991-1993 . . . . . Starting and ending dates for first and second series replications o f lesser appleworm oviposition preference experim ent . . . . . . 78 Oviposition preference by lesser appleworm in simultaneous choice experiment 80 Indexes o f preference for lesser appleworm oviposition on three different hosts . . . . 83 Larval and pupal characters for identification o f lesser appleworm Grapholita prunivora (Walsh), oriental fruit moth G. mo/esta (Busck), and cherry fruitworm G. packardi Zeller (Lepidoptera : Tortricidae). Table 1. Table 2. Table 3. Comparison o f pupal length, mesowing width, and anal segment width o f lesser appleworm (LAW ), oriental fruit moth (OFM ), and cherry fruitworm (CFW ) . . . . 95 Correlation coefficients for three pupal characters: length, width o f mesowing, and width o f anal segment for lesser appleworm (LAW ), oriental fruit moth (OFM), . . . and cherry fruitworm (CFW ) . 97 Accuracy o f species identification using visual characters to categorize pupae o f lesser appleworm (LAW ), oriental fruit moth (OFM ), and cherry fruitworm (CFW) . . . . . 98 Table 4. Table 5. Table 6. Comparison table o f numbers o f crochets on last pair o f ventral prolegs and on caudal prolegs on lesser appleworm (LAW ), oriental fruit moth (OFM ), and cherry fruitworm (CFW ) 107 Correlation coefficients for num ber o f crochets on last pair o f ventral prolegs and on anal prolegs for larvae o f lesser appleworm (LAW ), oriental fruit moth (OFM ), and cherry fruitworm (CFW ) . 108 Configuration o f prongs in anal comb in lesser appleworm (LAW), oriental fruit moth (OFM ), and cherry fruitworm (CFW ). 112 xii L IST O F FIG U R E S Chapter 2. Pest status o f lesser appleworm Grapholita prunivora (Lepidoptera : Tortricidae) in Michigan apple orchards. Figure 1. Figure 2. Figure 3. Chapter 3. Lesser appleworm flight seasonality during 1993 and 1994 in abandoned apple orchards Casnovia MI. 27 Lesser appleworm (LAW ), oriental fruit moth (OFM ), and codling moth (CM) fruit infestation in Douglas, Kalamazoo, Casnovia, and Shelby abandoned apple orchards during 1993 season . 33 Lesser appleworm (LAW ), oriental fruit moth (OFM), and codling moth (CM ) fruit infestation in Douglas, Kalamazoo, Casnovia, and Shelby abandoned apple orchards during 1994 season . . . . 34 Seasonality o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in M ichigan apple orchards. Figure 1. Location o f experimental sites in M ichigan Figure 2. Degree days base 50° F accumulation and lesser appleworm flight seasonality in Douglas, MI abandoned orchard during 1992 - 1994 45 Degree days base 50° F accumulation and lesser appleworm flight seasonality in abandoned orchard during 1993 - 1994, Shelby, MI. . . . 47 Figure 3. Figure 4. . Collection o f oriental fruit moth moths in lesser xiii 41 appleworm pheromone traps in comparison with regular oriental fruit moth traps, Fennville, MI 1993 -1 9 9 4 Chapter 4. Trap efficacy and flight bionom ics o f lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) in Michigan. Figure 1. Figure 2. Figure 3. Figure 4. C hapter 5. Lesser appleworm flight seasonality during 1992 and 1993 in the abandoned apple orchard, Douglas, MI. 62 Comparison o f average num ber o f lesser appleworm moths captured per trap during the season. 64 Lesser appleworm (LAW ) and oriental fruit moth (OFM ) flight pattern in relation to ambient temperature. . . . . . . 65 Crepuscular flight o f lesser appleworm (LAW ) and oriental fruit moth (OFM ) . . . . 66 Lesser appleworm Grapholita prunivora (W alsh) (Lepidoptera: Tortricidae) oviposition preference and female fecundity when reared in laboratory. Figure 1. Figure 2. Figure 3. Chapter 6. 51 Position o f fruit inside the boxes: a) one host design, b) two host design, c) three host design 77 Com parison o f mean num ber o f lesser appleworm progeny per combination during first and second series o f experiments . . . . . 82 Frequency histogram o f lesser appleworm Grapholita prunivora (W alsh) females fecundity when reared in simultaneous choice situation . . . . 86 Larval and pupal characters for identification o f lesser appleworm Grapholita prunivora (W alsh), oriental fruit moth G. molesta (Busck), and cherry fruitworm G. packardi Zeller (Lepidoptera : Tortricidae). Figure 1. Comparison o f pupal length and m esowing width o f xiv Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. three internal fruit feeders: lesser appleworm, oriental fruit moth, and cherry fruitworm 100 Comparison o f three pupal dimensions: length, m esow ing width, anal segment width o f lesser appleworm, oriental fruit moth, and cherry fruitworm 101 Frequency o f ratios between pupal length and width o f mesowing o f lesser appleworm, oriental fruit moth, and cherry fruitworm pupae. 102 Lesser appleworm Grapholita prunivora (W alsh) pupal cocoons: a) on apple fruit, b) on leaf, c) on Filter paper, and d) on hawthorn fruit. 103 Scanning electron microscope photographs o f dorsal abdominal part o f three tortricids pupae a) Grapholita prunivora (W alsh), b) Grapholita molesta (Busck), and c) Grapholitapackardi Zeller . 105 Comparison o f num ber o f crochets on o f ventral prolegs in lesser appleworm oriental fruit moth (OFM ), and cherry (CFW ) . . . . last pair (LAW ), fruitworm . . 109 Comparison o f num ber o f crochets on anal pair o f prolegs in lesser appleworm (LAW ), oriental fruit moth (OFM ), and cherry fruitworm (CFW ) 111 Apple fruits injured by lesser appleworm Grapholita prunivora (W alsh) larvae. 114 w CHAPTER 1 Introduction to lesser appleworm Grapholita prunivora (Walsh) (Lepidoptera : Tortricidae) in North America Introduction The lesser appleworm (LAW) Grapholita prunivora (Walsh) (Lepidoptera: Tortricidae) is a native North American insect. It is also a quarantined pest in Europe and Japan, and is one o f the major barriers in exporting U. S. apples to Japan. Although the pest status o f lesser appleworm is historically documented (Glass & Lienk 1971, Rivard & Mailloux 1974, Brown 1953), in Michigan the lesser appleworm is not presently considered as a major fruit pest (Howitt 1993). Growers who make regular insecticide applications against major fruit pests usually do not see fruit damage caused by this pest. From the late 1800’s and early 20 th century lesser appleworm was reported from different fruit growing areas as a possible pest in fruit orchards (Lugger 1898, Quaintance 1908). Early researchers compared the biology o f lesser appleworm to the biology o f codling moth Cydiapomonella (L.) (Taylor 1909). The first picture o f lesser appleworm fruit injury came from a publication about codling moth and was labeled as “apples damaged by unknown caterpillar” (Simpson 1903). The same picture was later used as classical view o f lesser appleworm fruit injury (Caesar 1911, Quaintance & Scott 1912). A historical Michigan orchard spray bulletin states th a t" lesser apple-worm, when present, requires a spray o f 1 2 poison" (Eustace & Pettit 1910). After the first description o f lesser appleworm (Walsh 1868) the insect gradually gained more and more attention from people working with fruit pests. Riley (1873) in Missouri, Fletcher (1898) in British Columbia, Lugger (1898) in Minnesota, and W ebster & Newell (1902) in Ohio reported lesser appleworm in their reports and publications related to insects o f economic importance. With the exception o f research data presented by Quaintance (1908), Foster & Jones (1909), Taylor (1909), Garman (1918), and Frost (1926) most o f the information about presence and importance o f the lesser appleworm comes from spray calendars or reports about insects affecting orchards (Sanderson et al. 1907, Eustace & Pettit 1910, Quaintance & Scott 1912, Dean & Peairs 1913, Quaintance & Siegler 1918, Fulton 1920, Pettit & Hutson 1931). This early interest in the importance o f lesser appleworm almost disappeared from research in the 1940’s, with scattered reports occurring only in extension bulletins with lesser appleworm as a pest o f apples or plums (Frost 1942, Newcomer 1941). Researchers renewed research efforts on lesser appleworm in the 1950's. Brown & Jones (1953) reported the lesser appleworm as an important pest for cherries, citing four years o f observations o f lesser appleworm biology as a pest on this fruit in Oregon. The last period o f research interest on this pest started in the late 1960’s, when Roelofs et al. (1969) discovered a sex pheromone o f lesser appleworm. Trapping technique studies followed this discovery (Gentry at al. 1974, Gentry at al. 1975, Willson & Trammel 1975, Willson & Trammel 1980). Observations about the lesser appleworm’s importance as a pest on apples during ten years o f studies was done in orchards where insecticide use was discontinued (Glass & Lienk 1971). They found that lesser appleworm caused 72 percent and 3 39 percent fruit damage respectively during the last two years o f the experiment. Weires et al. (1979) worked in apple orchards with reduced insecticide program in Hudson Valleys, NY, and found lesser appleworm responsible for approximately 50 % o f damage done by all internal lepidopterous feeders . Scientific and common names of G. prunivora. Mr. Benjamin D. Walsh (1868) in his first description o f lesser appleworm placed it first in the genus Semasia. Other names that exist in the literature are: Enarmoniaprunivora (Walsh), iMspcyresiaprunivora (Walsh), Cydiaprunivora (Walsh), and Grapholilha prunivora (Walsh). The Entomological Society o f America’s current official name (Stoetzel 1989) is Grapholita prunivora (Walsh). Forbes (1923) incorrectly used Walsingham as an author name and consequently it leads to some confusion regarding the correct author. Weires & Riedl (1991) in their most recent book cited lesser appleworm as Cydia prunivora (Walsingham) with obviously incorrect author name. After the first description o f G. prunivora (Walsh 1868) there were several common names functioning for the species currently called lesser appleworm (Stoetzel 1989). The first common name given by Walsh (1868) was plum moth and was used until the late 1800’s. Due to the similarity in appearance and biology to codling moth, other names that functioned during the following years placed an emphasis on a difference in size between those two insects. The other known names are: lesser apple worm (Fletcher 1898), lesser codling worm (Forbes 1923), lesser fruit worm (Anonymous, 1951). Lugger (1898) used the name apple bud moth, while Rivard & Mailloux (1974) called it “petite pyrale” . Rosenfeld (1910) used the scientific name Enarntoniaprunivora Fitch (?) for the insect that he called “ pecan huskworm” . 4 Geographical distribution Lesser appleworm is a native insect to North America (Quaintance 1908, CIE 1975), and has been reported only once from Asia (Arakawa 1927). Although there is also a record dating back to World W ar I from Sweden (CIE 1975), it and the Asian record are not accepted as correct, and lesser appleworm is considered as a quarantined pest in Europe (OEPP 1979), Japan and other countries (Johnson, pers. com. 1995) In North America the lesser appleworm occurs throughout most o f the important fruit growing regions. In the US the pest is reported in the following States: Arkansas, California, Colorado, Idaho, Illinois, Indiana, Iowa, Maine, Maryland, Missouri, New York, Ohio, Oregon, Pennsylvania, Virginia, Washington, Washington DC, Wisconsin (CIE, 1975) and Michigan (Eustace & Pettit 1910). In Canada lesser appleworm is reported in: British Columbia, Ontario, Manitoba (CIE 1975) and Quebec (Rivard & Mailloux 1974). Main hosts Lesser appleworm was first described as a pest on plum in Illinois by Walsh in 1868, then was also reported from other plants. The native hosts include rosaceous plants: wild hawthorn (Crataegus spp.), wild roses (Rosa sp ), crabapple (Malus spp.), christmasberry (Photinia sp.), as well as cultivated plants: apple (Malus sp.), pear (Pyrus sp.), peach , cherry, plum, and prunes (Prunus spp.) (Walsh 1868, Howard 1900, Simpson 1903, Quaintance 1908, Wellhouse 1920, Keifer 1933, Hoemer & List 1952, Brown 1953). The lesser appleworm is also reported from fungus galls o f black knot on plums and from insect galls on elm and oak (Walsh 1868, Anonymous 1922) although according to Quaintance (1908) "larvae did not infest sound plum and black-knots, but followed the injury caused by the 5 curculio, and in the elm and oak galls the larvae are guests, and it being uncertain whether they feed upon the tissue o f the gall, upon the gall insect, or in the case o f the elm leaf gall, upon the sugary dust secreted by the aphids". Lesser appleworm (as pecan huskwonn) is also recorded from pecan (( \v y a sp ) (Rosenfeld 1910). Life stages Egg: The eggs are laid singly on the young fruits or on the bottom surface o f leaves. The eggs o f lesser appleworm are small, 0.53 - 0.70 mm long and 0.51 - 0.55 mm wide (Foster & Jones, 1909). Fresh laid eggs are yellowish - white, and after a few days they show a pinkish ring. A day before hatching the darker anterior and posterior o f the larva are visible through the egg shell as a dark spot (Taylor, 1909) which is a feature very similar to the codling moth eggs. Larva: After hatching, larvae o f lesser appleworm immediately seek a fruit. The larvae enter the fruit mainly at the calyx end, and in case o f apple feed under the skin. As a shallow feeder, larva of lesser appleworm produce a blotch-type mine (Chapman & Lienk, 1971). Brown & Jones (1953) reported that in cherry, the larva bores deep into the fruit and feeds also in the area o f the pit or seed. There are also reports that the lesser appleworm larva can feed on terminal shoots o f young apple trees as well as infest water sprouts on older trees (Quaintance, 1908). The full grown larva is 6 to 8 mm long (Quaintance 1908) or 7.5 to 9.5 mm (Chapman & Lienk 1971). The larval head capsule is 0.77 to 0.85 mm in width (Chapman & Lienk 1971) and is brown to dark brown in color. As it is described by Quaintance (1908, p.: 55):" the ocellar spots, a spot caudal on cheek, and tips o f the well developed and strongly 6 toothed mandibles, black; sutural lines dark brown to blackish; width 0.75 to 0.85 mm., and about as long as wide. Thoracic shield is prominent, yellowish, transparent, often with darker markings on caudal margin near median line. Anal plate brownish, with comb-like structure on caudal curvature composed o f from 5 to 7 closely set dark, brown spines, the outer spine on each side considerably reduced. Spiracles small, dark brown; thoracic legs well developed, whitish, distal end dark, claw black. Abdominal prolegs well developed, each with a single circle o f from 25 to 27 strongly curved, sickle-like hooks. Tubercular are as disklikc, whitish, with a single, slender, light colored seta On third abdominal segment: tubercle I central, on dorso-lateral region; tubercle II caudo - ventrad o f I, on posterior annulet; tubercle III about its width above spiracle; tubercles IV and V coalesced, directly below spiracle, about twice as far from it as is tubercle III, the seta o f tubercle IV being considerably reduced; tubercle VI caudo - ventrad o f IV and V, and tubercle VII with three setae situated near base o f proleg". Simpson (1903) when writing about an "unknown caterpillar working on outer surface o f apples" reported that there are three setae on the pre-spiracular tubercule. Despite this relatively detailed description o f larvae o f lesser appleworm there is a strong similarity among larvae o f lesser apple worm, oriental fruit moth, Grapholita molesta (Busck), and cherry fruitworm, Grapholitapackardi Zeller. Recent authors indicate the only way to recognize lesser appleworm larvae from larvae o f these other two insects is that the body o f lesser appleworm larvae will retain a pinkish color after boiling in hot water, and placing in 70% alcohol (Stehr 1987, Chapman & Lienk 1971). MacKay (1959) separates oriental fruit moth larvae from the other two species by the number o f crochets and characteristics o f spinnerets, but she also was not able to find characters for separation o f lesser appleworm and cherry fruitworm larvae. 7 Pupa: The cocoon, is about 6 mm long, and is made o f bits o f surrounding bark and white silk, when larvae overwinter on tree (Quaintance, 1908). Pupae o f lesser appleworm are golden brown, with a length o f 4.5 to 6.0 mm (Brown 1953). During the spring, pupation in Oregon conditions takes about fourteen to eighteen days (Brown 1953). Pupae may also be found in the hollow stem o f dead weeds or attached to twigs or other suitable object where the larva makes its cocoon (Brown & Jones 1953). According to Quaintance (1908, p.: 56) who has given the most detailed description o f the life stages of lesser appleworm: "pupae o f lesser appleworm are about 5 mm long, uniformly brown except the thoracic region which is darker. On dorsum o f abdominal segments 3 to 7, between the spiracles on each sides, are two rows o f short, stout spines, projecting caudad, one row near cephalic border o f segments and one near center or on caudal margin, the spines o f caudal row smaller and more numerous. Remaining segments ( except 1 and 2, which are spineless) with a single row. Anal segment truncate, the 7 to 8 stout spines set on caudal margin Cremaster o f from 5 to 8 slender hairs hooked at tip and arising about equally distant from each other on caudal region o f anal segment. Spiracles slightly elevated, dark brown. Wing sheets and those o f third pair o f legs about equal in length and reaching middle o f fourth abdominal segment". Adler (1991) in her key to insect pupae in Eastern North America used size and location o f terminal spines and pupal size for separation o f lesser appleworm and oriental fruit moth pupae. A dult: The lesser appleworm adult is a small moth with an overall length o f 7.5 - 9.5 mm and forewing length o f 4.5 - 5.5 mm. The expanse o f the wings differs slightly between sexes but are within the range o f 9.5 to 11 mm (Chapman & Lienk 1971). The forewing 8 pattern contains scales o f five different colors: white, blue, grayish orange, rosaceus brown, and dark brown Life history. The lesser appleworm overwinters as a full grown larva in the debris on the ground (Brown & Jones 1953) or in cracks and crevices o f the bark o f apple trees and under bark scales on the tree trunk (Quaintance, 1908). The spring flight o f the first generation moth lasts normally three to four weeks during May and June ( Brown 1953, Chapman & Lienk 1971). Eggs are deposited singly on fruit or on upper surface o f leaves (Taylor 1909) and hatch in seven to twelve days in Oregon weather conditions (Brown 1953). Larvae o f the first summer generation may pupate either in the fruit or in the ground (Brown & Jones 1953). The pupation period o f the summer generation requires twelve to twenty four days, depending on the weather conditions (Taylor 1909, Brown 1953, Chapman & Lienk 1971). Three to four days o f this period is spent in the preparation o f a cocoon and in the prepupal stage. In Oregon, lesser appleworm required 47 to 57 days for completion o f the first generation and the second generation started in late June (Brown & Jones 1953). In eastern states the second generation started in late July or even August (Chapman & Lienk 1971). At Geneva NY, larvae o f second generation were found in fruit as late as October 20 (Chapman & Lienk 1971). Lesser appleworm as a multivoltine species completes two or three generations per year (Chapman & Lienk 1971, Rivard & Mailloux 1974, Dean 1969). In Michigan lesser appleworm has two generations during the year, with flight ending in late September or early 9 October (Howitt 1993). Pest status Lesser applewonu causes damage on the trees and fruit in several ways. Lugger (1898) reported that lesser applewonu eats the buds o f apple before they expand and cause "in this way more injury than if the leaves were eaten". Foster & Jones (1909) during July and August reared lesser applewonu adults from larvae found in young vigorous growing shoots and water sprouts o f apple trees. Brown & Jones (1953) reported lesser applewonu larvae feeding on sweet cherry fruit where the small hatching larva immediately searches for a fruit and mines under the outer skin, making a twisted tunnel. As the larva develops, it bores deep into the fruit and feeds entirely in the area o f the pit or seed. The maturing larva tunnels to the outside o f the fruit through the skin and drops to the ground. Authors referring to the lesser applewonu larvae on apples state that larvae enter the fruit usually on the calyx end (Quaintance 1908). Presence o f an inconspicuous pile o f frass at the feeding site at the calyx end or on the side o f fruit are the most reliable external signs o f infestation. Larvae feed beneath the skin at the periphery o f the central feeding site. Larvae o f lesser applewonn are shallow feeders, usually not tunneling deeper than about 'A inch and usually do not feed on the seeds (Chapman & Lienk 1971, Rivard & Mailloux 1974, Quaintance 1908). Glass and Lienk (1971), in their 10-year-long study in apple orchards maintained without any insecticide and acaricidal sprays found the lesser applewonu a significant pest. During the first six years o f study they did not observe any lesser applewonu fruit damage. In last two years lesser applewonu fed on 72% and 39% o f fruit respectively. At the same 10 time damage done by redbanded leafroller Argyrotaenia ve/ufinatta (Walker) and codling moth was reduced about 20% each, compared to previous years. While studying apple pests under reduced spray programs Weires et al. (1979) found lesser applewonu responsible for about 50 % o f the damage caused by all lepidopteran internal feeders. In comparison o f number o f codling moth and lesser appleworm larvae, Foster & Jones (1909) noted the relative seasonal increase o f lesser appleworm larvae over codling moth larvae. When during the beginning o f the season codling moth was more abundant and reared from up to 93 % o f infested fruit, during the second part o f the season lesser applewonu was present in over 70 % o f infested fruit. Forsythe (1976 -1993) reports in multiple "Insecticide and Acaricide Tests" that lesser applewonu causes injury in his control apple blocks. The highest observed infestation during those years was 22.0 % and the lowest 0.4 %. During his multi - year experiments 44% o f his control blocks had lower than 3 % fruit damage caused by lesser applewonu. Control strategies. Currently, in the orchard under standard protection maintenance, lesser appleworm does not receive specific treatments for its control. Similarity o f its biology to the biology o f codling moth and presence o f infectious stages o f both species at the same time in the orchard, creates a situation where insecticide applications against codling moth appear to control lesser appleworm (Caesar 1911, Anonymous 1922). Use o f codling moth mating disruption complicates that situation, and the grower may be forced to use specific lesser appleworm treatments. Carde et a! (1977) demonstrated that lesser appleworm males can also be completely disrupted in field situations by using a synthetic mixture o f Z - 8: Ac with 2 % and 7% E8 - 12. Ac. In Michigan lesser applewonu is not listed in the current “Fruit Spraying Calendar” as a pest o f consideration (Hull et al. 1994); however, if control is 11 necessary standard compounds are recommended as for codling moth (Howitt 1993). Natural enemies The complex o f natural enemies o f tortricid pests o f fruit is generally well known and described. Numerous predators and parasitoids are known to be very important in reducing tortricid pest populations (Mills & Carl 1991, Zimmermann & Weiser 1991). Approximately 130 species o f parasitoids (mostly Hymenoptera, with a few species o f Diptera) have been recorded to feed on oriental fruit moth. Macrocentrus aucylivnrus Rohwer (Hymenoptera: Braconidae) a native North American parasitoid is able to reduce populations o f oriental fruit moth by 70 % (Philips & Proctor 1970). The predator complex o f oriental fruit moth includes, lady beetles, lacewings, thrips that feed on eggs, ground beetles and spiders (Rothschild and Vickers, 1991). There are not detailed studies on natural enemies o f lesser appleworm. Foster and Jones (1909) reared M i raxyiapholithau Ashm (Hymenoptera: Braconidae) and Phanerotoma sp. (Hymenoptera: Braconidae) from lesser appleworm larvae. Cushman (1913) reported that larvae o f Enarnionia sp. were parasitized by ( ’alliephialtes sp. (Hymenoptera: Ichneumonidae). Sex pheromone In 1959, Karlson & Butenandt and Karlson & Luscher were the first to use the term "pheromone" to refer to substances emitted by one individual and elicited a specific reaction in a second individual o f the same species (Karlson & Luscher 1959). From the beginning pheromones were regarded as an alternative means o f pest control; some people almost 12 thought o f them as a " new third generation o f pesticides" (Carde 1976) Pheromones are composed o f combinations o f different chemicals. Primary components are chemicals emitted by an insect that elicit long-distance upwind anemotaxis in the responding insect. Secondary sex pheromone components are chemicals emitted by an insect that are not essential for eliciting upwind anemotaxis, but that in combination with the primary components evoke other aspects o f the mating sequence. Generally close range responses to mating behavior are induced by secondary components (Roelofs & Carde 1977). Primary components o f lesser appleworm sex pheromone are (Z) - 8 -dodecenyl acetate (Z8-12:Ac) and (E)- 8 -dodecenyl acetate (E8-12:Ac) (Roelofs et al. 1969). These main components are also shared by other Graphnliia species. The most important difference appears to be the ratio o f the mixture. Oriental fruit moth is best attracted to mixtures o f Z 8 12: Ac and E8-12:Ac in a 100 : 7 ratio (Roelofs & Carde 1974) while European plum moth, Graphnliki funehrana (Treitschke) is attracted best at a 100 : 4 ratio ( Am et al. 1976). The redbanded leafroller Arg)ro/acnia velu/inana (Walker) and European com borer Ostrinia nuhitalis (Hiibner) sex pheromones are further examples o f the importance o f minor amounts o f opposite geometrical isomers for sex attraction (Klun et al. 1973). For lesser applewonu the best mixture o f sex pheromone chemicals contains 2,2 % o f E8-12:Ac (Roelofs & Carde 1974). A higher percentage o f tram (E) isomer plays an inhibitory role in attracting lesser appleworm males ( Roelofs & Carde, 1974), although Baker & Carde (1979) found that optimum blend for capturing LAW in pheromone traps included 5.1% o f the cis (E) isomer. Roelofs et al. (1969) stated that males o f lesser applewonu were not attracted to females o f oriental fruit moth and suggested the possible role o f secondary components. Oriental fruit moth sex pheromone efficacy is additionally affected by the presence o f two 13 components in the pheromone mixture: dodecanol (12:OH) and (Z)-8 -dodecenyl alcohol (Z8-12:OH) (Baker & Carde 1979, Carde et al. 1975, Carde et al. 1979). For oriental fruit moth, the addition o f dodecyl alcohol improved attractiveness o f primary compounds when used for moth trapping while for lesser apple worm there were no changes in trap efficacy. The addition o f Z8-12:OH to lesser appleworm pheromone drastically reduced lesser appleworm male capture. The differences in response to cv'.v and tram isomers, and the inhibitory action o f Z8-12:OH are believed to be very important in causing reproductive isolation between these sympatric, highly synchronic species (Baker & Carde 1979, Roelofs & Brown 1982). The availability of synthetic insect sex pheromones creates an opportunity for their use as a control alternative to insecticides (Rice & Kirsch 1990). Mating disruption for control o f oriental fruit moth as well as codling moth has become a more and more common practice in West Europe, USA and Australia ( Carde et al. 1977, Pfeiffer & Killian 1988, Rice & Kirsch 1990, Pfeiffer et al. 1993, Carde & Minks 1995). Good results in controlling oriental fruit moth are reported by Vickers et al. (1985) where mating disruption proved to be effective and comparable in costs with traditional insecticides. In California, mating disruption for oriental fruit moth control has also become a feasible alternative to insecticide control (Rice & Kirsch 1990). By comparing abandoned blocks with insecticide, organic, and pheromone treated Virginia apple orchards Pfeiffer et al. (1993) showed that mating disruption can be effective when compared to other tactics. Using oriental fruit moth sex pheromone for mating disruption, Pfeiffer & Killian (1988) showed its effectiveness for controlling oriental fruit moth and lesser appleworm populations. These authors achieved 100 % shutdown o f trap catch and almost no fruit 14 damage. Carde et al. (1977), used a synthetic blend o f oriental fruit moth sex pheromone demonstrating 100 % disruption o f sexual communication in field conditions o f oriental fruit moth and lesser appleworm. Mating disruption with all its advantages may also create some problems. The pheromones are manufactured for control o f one species or one group o f insects (Carde & Minks 1995). By the elimination o f insecticide treatments, and substituting it by speciesspecific pheromone control, we may create a situation where other secondary insect pests may re-establish in orchards and become significant pest problems. Rice & Kirsch (1990), after using mating disruption for control o f oriental fruit moth in a peach orchard, noted the increased significance o f peach twig borer, Anarsia lineatella (Zeller), and omnivorous leafroller, Platyuota slultcma (Walsingham), pests normally considered as secondary for peach orchards. References cited: Adler, C. R. L. 1991. Identification o f pupae on apple in Eastern North America, in: Tortricid pests, their biology, natural enemies and control, ed. by: L. P. S. van der Geest & H. H. Evenhuis, Elsevier, Holland, pp: 51 - 64. Anonymous, 1922. The more important apple insects. U S. Department o f Agriculture Fanners. Bulletin No. 1270, pp. 10 Anonymous, 1951. Insect that attack the apple in Pennsylvania. The Pennsylvania State College, School o f Agriculture. Agricultural Experiment Station. Bulletin 535. pp. 13. Arakawa, Y. 1927. Studies on moths infesting apples in Manchuria. Manchuria and Mongolia pp. 1-46, Koshurei, Manchuria, /from Review o f Applied Entomology / Am, H., B. Delley, M. Baggiolini, & P. J. Charmillot. 1976. Communication disruption with sex pheromone attractant for control o f the plum fruit moth Grapholitha fitnebrana. a two year field study. Ent. Exp. & Appl. 19. 139-147 15 Baker, T. C. & R. T. Carde. 1979. Analysis o f pheromone- mediated behaviors in male Grapholilha molesta, the oriental fruit moth (Lepidoptera: Tortricidae). Environ Entomol. 8 : 956-968. Brown, E. E. 1953. Life cycle o f lesser apple worm in northeastern Oregon. J. Econ. Entomol. 46:163. Brown, E. E. & S. C. Jones. 1953. The lesser apple worm and its control in northeastern Oregon. Agricultural Experiment Station. Oregon State College Comvalis. Circular of Information 521. Caesar, L. 1911. The codling moth. Ontario Department o f Agriculture. Ontario Agricultural College. Bulletin No. 187 Carde, A. M., T. C. Baker, & R. T. Carde. 1979. Identification o f a four- component sex pheromone o f the female oriental fruit moth, Grapholitha molesta (Lepidoptera: Tortricidae). J. Chem. Ecol. 5: 423-427. Carde, R. T., 1976, Utilization o f pheromones in the population management o f moth pest. Environmental health perspectives, 14: 133 - 144. Carde, R. T., T. C. Baker, & P. J. Castrovillo. 1977. Disruption o f sexual communications in lxispeyresiapomonella (Codling moth), GrapholHa molests. (Oriental fruit moth) and G. pmnivara (Lesser appleworm) with hollow fiber attractant sources. Ent. Exp. et App. 22: 280 - 288. Carde, R. T., T. C. Baker, & W. L. Roelofs. 1975. Behavioral role o f individual components o f a multichemical attractant system in the Oriental Fruit Moth. Nature 253: 348 349. Carde, R. T. & A. K. Minks. 1995. Control o f moth pests by mating disruption: successes and constrains. Ann. Rev. Entomol. 40: 559-585 Chapman, P. J. & S. E. Lienk. 1971. Tortricid fauna o f apple in New York (Lepidoptera: Tortricidae); including an accounts o f apples' occurrence in the State, especially as a naturalized plant. New York State Agricultural Experimental Station, Geneva, Special Publication, 122p. C I E (Commonwealth Institute o f Entomology), 1975. Distribution maps o f pests. Series A (Agriculture), MAO No. 341, June 1975 Cushman, R. A. 1913. The Calliephialtes parasite of codling moth. IL. Agric. Research Dept. Agric. Washington, 1:211 - 237. Dean, R. W. 1969. Moth activity in Hudson Valley orchards- trapping records o f seven pest 16 species. New York Agr Exp. Stat. Bulletin No. 823. 34p. Dean, G. O. & L. M. Peairs. 1913. Insect injurious to fruit. Kansas State Agricultural College. Extension Division. Agricultural Education Vol. VI, No. 2 Eustace, H. J. & R. H. P e ttit. 1910. Spray and practice outline for fruit growers, Michigan State Agricultural College, Experiment Station, Bulletin No. 51. Fletcher, J. 1898. Report o f Entomologist and Botanist to the Central Experimental Station, Canada, p. 199. Forbes, W. T. M., 1923, The Lepidoptera o f New York and neighboring states. Cornell University, Agricultural Experiment Station, Memoir No. 63, p. 392. Forsythe, Jr., H. Y. 1976 - 1993. Pome fruit reports. Insecticide and Acaricide Tests. Volumes.: 1-18 various pages Foster, S. W. & P. R. Jones. 1909 Additional observations on the lesser apple worm. U. S. Department o f Agriculture, Bureau o f Entomology, Bulletin No. 80, Part III, pp: 4550. Frost, S. W. 1926. Certain genitalic characters in iMspcyresia molesta Busck and Ixuspeyrcsia prunivora Walsh. Annals Entomological Society o f America 19. 198201. Frost, S. W. 1942. Common insect larva that attack the apple in Pennsylvania. The Pennsylvania State College. School o f Agriculture, Agricultural Experimental Station. Bulletin 420, pp. 11. Fulton, B. B. 1920. Insect injuries in relation to apple grading. New York Agricultural Experiment Station. Geneva, Bulletin No. 475. Garman, P. 1918. A comparison o f several species o f Lepidoptera infesting peach and apples in Maryland with additional notes on the oriental peach moth. The Maryland State College of Agriculture. Agricultural Experiment Station. Bulletin No. 223. Gentry, C. R., M. Beroza, J. L. Blythe, & B. A. Bierl. 1974. Efficacy trials with the pheromone o f the oriental fruit moth and data on the lesser appleworm. J. Econ. Entomol. 67: 607-609. Gentry, C. R., M. Beroza, J. L. Blythe, & B. A. B ierl. 1975. Captures o f the oriental fruit moth, the pecan bud moth, and the lesser appleworm in Georgia field trials with isomeric blends o f 8 -dodecenyl acetate and air- permeation trials with the oriental fruit moth pheromone. Environ. Entomol. 4: 822-824. 17 Glass, E. H. & S. E. Lienk . 1971 Apple insect and mite populations developing after discontinuance o f insecticides: 10-year record. J. Econ. Entomol. 64. 23-26. Hoemer, J. L. & G. M. List 1952. Controlling cherry fruitworm in Colorado. J. Econ. Entomol. 45: 800-805. Howard, L. O. 1900. Some miscellaneous results o f the work o f the Division o f Entomology. U. S. Department o f Agriculture, Division o f Entomology, Bulletin No. 22, New Series. Howitt, A H. 1993 Common tree fruit pests. Michigan State University Extension NCR 63, 252 p. Hull, J., A. L. Jones & J. W. Johnson. 1994. Fruit spraying calendar. Michigan State University. Extension Bulletin E - 154, 128 p. Karlson, P. & A. Butenandt. 1959. Pheromones (octohormones) in insect. Ann. Rev. Entomol. 4: 39-58. Karlson, P. & M. Luscher . 1959. "Pheromones” : A new term for a class o f biologically active substances. Nature 183: 55-56 Keifer, H. H. 1933. The lesser apple worm (Grapholilaprunivora Walsh) in California. J. Econ. Entomol. 26: 509. Klun, J. A., O. L. Chapman, K. C. Mattes, P. W. Wojtkowski, M. Beroza, & P. E. Sonnet. 1973. Insect sex pheromones: minor amount o f opposite geometrical isomer critical to attraction. Science 181: 661-662 Lugger, W. P. 1898, The apple bud moth. Minnesota Agricultural Experiment Station. Bulletin No. 61. pp. 295. MacKay, M. R. 1959. Larvae o f the North American Olethreutidae (Lepidoptera). Can. Entomol. 91 (Suppl. 10). 338p. Mills, N. J. & K. P. C a rl. 1991. Natural enemies and pathogens; parasitoids and predators, in: Tortricids pests, their biology, natural enemies and control ed. by: van der Geest L. P. S., Evenhuis H. H. Elsevier, Holland pp: 235-251. Newcomer, E. J. 1941. Orchards insects o f the Pacific Northwest and their control. U. S. Department o f Agriculture Circular No. 270. pp. 59. OEPP, . 1979. Data sheets on quarantine organisms. EPPO List A l. European and Mediterranean Plant Protection Organization. 9(2): 1-7. 18 Pettit, R. H. & R. Hutson. 1931. Pests o f apple and pear in Michigan. Agricultural Experiment Station. Michigan State College. Circular bulletin No. 137, pp. 44 Phillips, J H & J R. Proctor. 1970. Parasitism o f oriental fruit moth Grapholifha molesla (Lepidoptera: Tortricidae) in an unsprayed orchard on the Niagara Peninsula, Ontario. Can. Entomol. 102: 454-471. Pfeiffer, D. G., W. Kaakeh, J. C. Killian, M. W. Lachance, & P. Kirsch. 1993. Mating disruption for control o f damage by codling moth in Virginia apple orchards. Entomol. Exp. Appl. 67: 57-64. Pfeiffer, D. G. & J. C. Killian. 1988. Disruption o f olfactory communication in oriental fruit moth and lesser appleworm in a Virginia peach orchard. J. Agric. Entomol. 5: 235239. Quaintance, A. L. 1908. The lesser apple worm. U. S. Department o f Agriculture, Bureau o f Entomology. Bulletin No. 68 , Part V. Washington 1908. Quaintance, A. L. & W. M. Scott. 1912. The more important insect and fungous enemies of the fruit and foliage o f the apples. U. S. Department o f Agriculture. Fanners' Bulletin 492. Quaintance, A. L. & E. H. Siegler . 1918. Information for fruit growers about insecticides, spraying apparatus , and important insect pests. U. S. Department o f Agriculture. Fanners Bulletin 908. Rice, R. E. & P. Kirsch. 1990. Mating disruption o f oriental fruit moth in the United States, in: Behavior - modifying chemicals for insect management. Application o f pheromones and other attractants. ed. by: Ridgway, R. L., R. M. Silverstein, & M. N. Inscoe. Marcel Decker, Inc. New York and Basel, pp. 193-211 Riley, C. V. 1873. Fifth annual report on the noxious, beneficial and other insect o f the State o f Missouri pp. 51. Rivard, I & M. Mailloux . 1974. Grapholitaprunivora (Walsh) (Lepidopteres: Ole/hreuticiae) dans les pommeraies du sud-ouest du Quebec. Phytoprotection 55: 29-32. Roelofs, W. L. & R. L. Brown. 1982. Pheromones and evolutionary relationships of Tortricidae. Ann. Rev. Ecol. Syst. 13: 395-422 Roelofs, W. L. & R. T. Carde. 1974. Oriental fruit moth and lesser appleworm attractant mixtures refined. Environ. Entomol. 3: 586 - 589 Roelofs, W. L .& R. T. Carde. 1977. Responses o f Lepidoptera to synthetic sex pheromone chemicals and their analogues. Ann. Rev. Entomol. 22: 377- 405. 19 Roelofs, W. L., R. T. Carde, & J. P. Tette. 1973. Oriental fruit moth attractant synergists. Environ. Entomol. 2: 252-254. Roelofs, W. L., A. Comeau, & R. Selle. 1969. Sex pheromone o f the oriental fruit moth. Nature (London) 224:723. Rosenfeld, A. H. 1910. Insect notably injurious in Louisiana during 1908 and 1909. J. Econ. Entomol. 3: 212-217. Rothschild, G. H. L. & R. A. Vickers. 1991. Biology, ecology and control o f the oriental fruit moth, in: Tortricid pests, their biology, natural enemies and control, ed. by: L. P. S. van der Geest & H H Evenhuis, Elsevier, Holland, pp. 389-411. Sanderson, E. D., C. Brooks, & T. J. Headlee. 1907. Spraying the apple orchard. New Hampshire College, Agricultural Experiment Station Bulletin 131. pp. 23-27. Simpson, C. B. 1903. The codling moth. U. S. Department o f Agriculture Division o f Entomology. Bulletin No. 41, pp. 23, Plate II. Stehr, F. W. 1987. Immature Insect, Kendall, Hunt Publishing Company, Dubuque, Iowa, pp. 427. Stoetzel, M. B. 1989. Common names o f insects and related organisms. Entomological Society o f America. 199 p. Taylor, E. P. 1909. Eggs and stages o f the lesser apple worm (Enarmonia prunivora Walsh). J. Econ. Entomol. 2: 237-239. Vickers, R. A., G. H. L. Rothschild, & E. L. Jones. 1985. Control o f the oriental fruit moth, ( yJia molesta (Busck) (Lepidoptera: Tortricidae), at a district level by mating disruption with synthetic female pheromone. Bull. Ent. Res. 75: 625-634. Walsh, B. D. 1868. First annual report on the noxious insects o f the State o f Illinois, from The Appendix to the Transaction o f the Illinois State Horticultural Society. Chicago. Illinois. Webster, F. M.& W. Newell. 1902. Insect o f the year in Ohio. U. S. Department o f Agriculture Division o f Entomology Bulletin No. 31, New Series pp. 89. Weires, R. W., F. J. McNicholas, G. L. Smith, J. F. Schadt, & L. H. Waters. 1979. Reduced spray programs for apple pests in the Champlain and Hudson Valleys. Search (Agriculture) 9(6): 1-11. Weires, R. & H. Riedl. 1991. Other tortricids on pome and stone fruits, North American species, in: Tortricid pests, their biology, natural enemies and control, ed. by: van der Geest L. P. S. & H. H. Evenhuis, Elsevier, Holland, pp: 413-429. 20 Wellhouse, W. H. 1920 Wild hawthorns as a host o f apple, pear and quince pests. .1. Econ. Entomol. 13:388-391. Willson, H. R. & K. Trammel. 1975. Relationship between sex pheromone trapping o f six tortricids and a foliage index o f apple orchard canopies. Environ. Entomol. 4: 361364. Willson, H R. & K Trammel 1980. Sex pheromone trapping for control o f codling moth, oriental fruit moth, lesser appleworm, and three Tortricid leafrollers in a New York apple orchards. J. Econ. Entomol. 73. 291-295. Zimmennann, G & J. Weiser. 1991. Pathogens and diseases, in: Tortricid pests, their biology, natural enemies and control, ed. by: L. P. S. van der Geest & H. H. Evenhuis, Elsevier, Holland, pp. 253 - 272 CHAPTER 2 Pest status of lesser appleworm Grapholitaprunivora (Walsh) (Lepidoptera: Tortricidae) in Michigan apple orchards Abstract The occurrence o f lesser appleworm GrapholHaprunivora (W alsh) in south west M ichigan apple orchards was studied during 1993 and 1994. Four com mercially managed and four abandoned orchards were used for evaluating the lesser appleworm fruit infestation level. Injury caused by lesser appleworm looks sim ilar and is often misinterpreted as damage done by other internal fruit feeders; therefore, all collected im m ature insects were reared to adult stage. In all commercial blocks studied, there was no fruit with injury caused by this insect. Adults o f lesser appleworm, codling moth, oriental fruit moth and cherry fruit moth were reared from fruits collected in abandoned orchards. Infestation by lesser appleworm was very low, with 89 % o f examined samples having less than 3 % infested fruits. Lesser appleworm although present in the M ichigan apple system, is not a pest in commercial orchards and damage is controlled by standard orchard management. 21 22 Introduction K nowing and understanding the biology and occurrence o f an insect is one o f the m ost im portant elements o f pest management. D etermining the im portance o f an insect as a pest for a specific crop is a crucial elem ent in effective prevention o f yield loss. In an orchard ecosystem, with many insects considered as important pests, the occurrence o f a potential new pest may not always create a need for additional control. The lesser appleworm (LAW ), Grapho/ifaprunivora (W alsh) (Lepidoptera: Tortricidae) is a common insect in apple orchards. It is reported throughout the northern United States and from the southern provinces o f Canada (Chapman & Lienk 1971, Rivard & M ailloux 1974). As a native North American species, lesser appleworm has been collected from wild and cultivated hosts including: hawthorn ( ( 'rafegus s p p ), wild rose (Rosa sp.), christmasberry (Photinia sp.), crabapple (Mahis sp ), cherry and plum (Primus spp ), and apple (Malus domestica) (W ellhouse 1920; Keifer 1933; Chapm an & Lienk 1971). The lesser appleworm has also been found in black knot galls on plum and from insect galls on elm (l/l/uus sp.) and oak (Quercus sp.) (Anonym ous 1922). Since the first reference about lesser appleworm (form erly known as “ a plum m oth”) in plums (W alsh 1868) there have been three periods o f research interest. The first occurred in the early 1900’s. A fter the work o f Quaintance (1908) and Foster & Jones (1909) on the biology o f the moth, the lesser appleworm was found as a pest in all m ajor fruit grow ing areas throughout United States and Canada (Sanderson et al. 1907, Dean and Peairs 1913, Quaintance & Scott 1912). Early in this century the M ichigan orchard spray bulletin stated that “ lesser apple-worm, when present, requires a spray o f poison” (Eustace & Pettit 1910). 23 The second period o f renewed research efforts on lesser appleworm began in the 1950’s, with Brown and Jones (1953) reporting the lesser appleworm as an im portant pest for cherries, citing four years o f observations on this fruit in Oregon. The most recent period o f research interest in lesser appleworm started with the discovery o f the lesser appleworm fem ale sex pheromone (Roelofs et al. 1969). Q uestions about its biology and pest status were raised ever since growers caught high numbers o f this moth in pherom one traps, even thought no dam age was found in fruit. Lesser appleworm is currently a quarantine pest in Europe (OEPP 1979) and is considered one o f the major phytosanitary barriers to exporting U. S. grown apples to Japan (J. Johnson, personal comm. 1991). Although several references indicated that lesser appleworm was a pest (Glass & Lienk 1971, Brown & Jones 1953), current fruit production systems limit its importance in commercially grown fruit (Beers et al. 1993). G rowers who m onitor and manage m ajor pests using insecticides report only sporadic fruit damage caused by this insect. The objectives o f this study were to document the presence and significance o f lesser appleworm in abandoned and commercial apple orchards in M ichigan and to com pare the level o f damage that lesser appleworm does to fruit with other tortricid internal fruit feeders that are currently considered to be a major pests in orchards. Materials and Methods Experim ental sites. This study was conducted during 1993 - 1994 in four different apple growing regions o f M ichigan. W ithin each region, one abandoned and one com m ercially managed apple orchard were selected for data collection. In the Kalam azoo 24 region, the abandoned orchard was located inside the city limits, and no other apple sites w ere nearby. The Douglas abandoned orchard was surrounded by a commercial plantation o f apples and cherries. In the Casnovia and in the Shelby regions abandoned orchards w ere located about 2 km from the nearest commercial apple blocks. All unmanaged orchards had received no pesticide or cultural m aintenance programs for at least five years prior to the study. The size o f orchards varied from about 1 ha in Casnovia, to 3-5 ha in the rem aining sites. The abandoned orchards consisted o f mixed varieties o f apples on standard rootstocks mostly “Red D elicious” , “ Idared” and “ Jonathan” . Trees in each orchard were more than 20 years old. Commercial orchards w ere separated by a distance o f 6 - 10 km from abandoned blocks. The Casnovia and Kalamazoo orchards had mainly “Golden D elicious” plantings, w hile Douglas and Shelby orchards had “Red Delicious” and “ Idared” as the main apple varieties. Each commercial orchard was managed independently by the ow ner according to local conditions. Sample collection. During 1993 and 1994 fruit samples from each orchard were collected every week for 15 weeks starting two weeks after the beginning o f flight o f first generation lesser appleworm. The final samples were collected during commercial harvest time for each variety o f apple. In each commercial and abandoned orchard, four trees were randomly chosen every week for fruit collection. In abandoned orchards 100 random ly chosen fruits per tree from different sides o f the tree were collected. In commercial blocks, 100 apples w ere evaluated on each tree and only fruits with visible dam age were collected for further observation. In 1993 in the Douglas abandoned orchards, a sample o f 100 fruit was collected from m ore than one tree, because few fruits 25 were available due to early season frost. Pherom one traps were used for monitoring flight o f lesser appleworm adults. Pherocon II traps (Trece Inc.) with lesser appleworm lure (Scentry Inc.) w ere placed in the center part o f each block at 1.5 m height in the beginning o f the season. Traps were checked weekly for adult moth capture. Traps and pheromones w ere replaced every four weeks. Fruit evaluation. Collected fruit were placed in plastic boxes (40.3 cm L x 27.7 cm W x 15.1 cm H) with mesh tops. A thin layer (0.5 cm) o f fine verm iculite on the bottom o f each box and 20 strips o f corrugated paper (~ 1 . 5 x 4 cm) provided space for larval pupation. Boxes were put in growth chambers with a 16 : 8 (L : D) h photoperiod and 25 : 15°C temperature. A fter two weeks in the growth chamber, the fruit, corrugated paper, and verm iculite were examined for the presence o f larvae and pupae. All collected larvae were placed in plastic Petri dishes (100 mm D x 15 mm H) with cotton and small pieces o f fruit for further rearing. Pupae were placed in plastic vials (75 mm H x 15 mm D) with vented tops. Larvae and pupae were held in a growth chambers under the same conditions as the fruits. Adults w ere identified to species. Statistical analysis. For comparison o f fruit infestation by different internal fruit feeders, mean numbers o f reared insects were compared To avoid repeated measurements oriental fruit moth, codling moth and lesser appleworm fruit infestation in relation to location and year w ere analyzed separately by two way analysis o f variance (ANOVA) and means from n = 15 samples per year w ere com pared using HSD Tukey’s com parison o f mean at P =0.05 (CoStat 1990). The four orchards used for each growing season were considered as replicate blocks. K olmogorow - Smirnow test was used for 26 testing norm ality o f frequency distributions o f lesser appleworm fruit infestation (CoStat 1990, Sokal & R ohlf 1981). Results and Discussion Under M ichigan weather conditions lesser appleworm had two generations per year. The first generation flight started in the beginning o f May ( D D 50 : 200-225) with maximum moth flight during middle o f June. The flight o f second generation started in early August (D D 50 : 1500-1700) and continued through the end o f September with peak flight activity in late August. The typical flight seasonality o f lesser appleworm in abandoned and commercial orchards in Casnovia are shown on Figure 1. The four studied regions showed a difference in moth activity by calendar days but sim ilar tim ing when plotted against degree-days base 50 F accumulation. The pheromone trap catch o f the spring population o f lesser appleworm in commercial orchards during spring o f 1993 and 1994 were twice o f that in abandoned orchards; however, during flight o f the second generation lesser appleworm the pherom one trap catch o f adults in commercial blocks was minimal (Figure 1). In all four regions, no lesser appleworm injury was found on fruit during study in commercially protected orchards where pesticides were applied according to current needs, even when moths were caught in pheromone traps in orchards. This indicates that the insecticidal control targeted for the major apple pests also protected fruit against potential injury from lesser appleworm. The presence o f adults in orchards during the spring m ight be due to migration from wild hosts, especially since each com mercially protected block that was sampled was located near the border o f the orchard. The lack o f detectable 27 8 0 Number of moths per w eek Casnovia 1993 C o m m e rc ia l A bandoned 60 40 20 5/16 5/30 6/13 6/27 7/11 7/25 8/8 8/22 9/5 9/19 10/3 10/17 40 Commercial Number of moths per week Casnovia 1994 Abandoned 30 20 10 0 5/16 5/30 6/13 6/27 7/11 7/25 8 /8 8/22 9/5 9/19 Date Figure 1. Lesser appleworm flight seasonality during 1993 and 1994 in abandoned and commercial apple orchards Casnovia Ml. 10/3 10/17 28 injury on fruit was probably related to the protectant activity o f insecticides used for control o f other pests in the commercially protected orchards. Lesser appleworm was successfully reared from fruit collected from all abandoned orchards. There w ere no significant differences in fruit infestation by lesser appleworm between 1993 and 1994 (F = 2.903; d f = 1, 3; P = 0.091 ns) (Table 1). Fruits in Douglas and Casnovia abandoned orchards ( P = 0.05) had significantly higher lesser appleworm fruit infestation than fruits from Shelby and Kalamazoo orchards (F = 7.61; d f =3, 1; P < 0.001). In case of oriental fruit moth there was a significant difference among mean fruit infestations during 1993 and 1994 (F = 6.598; d f = 1, 3; P = 0.0115), w hile for codling moth no significant differences w ere detected (F -3 .1 4 ; d f = 1, 3; P = 0.079). Oriental fruit moth fruit infestation was significantly higher in the Douglas abandoned orchard than in others (F = 32.47; d f = 3,1; P = .000). For codling moth mean fruit infestation w ere significantly lower in Casnovia orchard than in Douglas, Kalamazoo, and Shelby abandoned blocks (F = 4.606; d f = 3,1; P = 0.0044). Mean fruit infestation for studied pests during 1993 and 1994 in abandoned orchards o f all regions are presented in Table 2. Frequency analysis on samples collected from abandoned blocks showed that in 89.2 % o f samples lesser appleworm infestation ranged from 0 to 3 % (Table. 3). Out o f n = 120 samples collected during two years we found infestation higher than 3 % only in 13 samples, all o f them from the Douglas and Casnovia abandoned orchards. In addition to lesser appleworm, three other internal fruit feeding tortricids were reared from fruit collected from abandoned orchards: codling moth C ydiaponwnella 29 T ab le 1. Tw o way analysis o f variance (ANOVA) o f lesser appleworm fruit infestation in four abandoned apple orchards in M ichigan. Source df MS F P Lesser appleworm Year 1 4.7 2.9 .0912 ns Location 3 12.32 7.61 .0001 *** Year x loc 3 6.31 3.89 .0108 * 112 1.61 Error Oriental fruit moth Year 1 296.88 6.59 .0115 * Location 3 1461.07 32.47 .0000 *** Year x loc Error 3 302.38 6.72 .0003 *** 112 44.99 Codling moth Year 1 47.81 3.14 .0790 ns Location 3 70.11 4.6 .0044 ** Year x loc 3 13.65 0.89 .4451 ns 112 15.22 Error * = 0.01 < P < 0.05 ** = 0.001 < P < 0.01 *** = P< 0.001 Table 2. Mean fruit infestation by four internal fruit feeders: lesser appleworm (LAW), oriental fruit moth (OFM), codling moth (CM), and cherry fruitworm (CFW) in four abandoned Michigan apple orchards during 1993 and 1994. Location Number of samples Mean fruit infestation ± SD n 1993 LAW OFM CM CFW Douglas 15 1.95 ± 2.39 22.58 ± 17.42 7.78 ±8.43 0.00 Casnovia 15 1.13 ± 1.91 2.38 ±3.25 2.47 ± 1.97 0.00 Shelby 15 0.23 ± 0 .6 2 1.68 ±2.55 2.47 ± 1.97 0.00 Kalamazoo 15 1.20 ± 1.96 2.88 ±2.81 4.70 ±5.51 0.02 + 0.13 1994 Douglas 15 2.00 ±2.13 10.00 ± 8.89 4.47 ±3.33 0.38 ±0.71 Casnovia 15 2.48 ± 2.04 3.13 ±3.26 2.56 ± 2.99 0.15 ± 0.40 Shelby 15 1.20 ± 1.51 2.63 ±2.93 4.51 ± 3.32 0.03 ±0.18 Kalamazoo 15 0.58 ± 0.94 1.08 ± 1.38 3.43 ± 3.22 0.12 ±0.45 Table 3. Frequency analysis for fruit infestation by lesser appleworm (LAW) in four Michigan abandoned apple orchards analyzed for normality o f distribution by Kolmogorow - Smimow test. Percent of fruit infested by Number o f samples Percentage of LAW n samples 0. 0 0 -0 .9 9 56 1 .0 0 -1 .9 9 Expected frequency Deviation 46.67 42.23 13.77 33 27.50 33.92 -0.92 2.00 - 2.99 18 15.00 26.72 -8.72 3 .0 0 -3 .9 9 6 5.00 12.74 -6.74 4.00 - 4.99 3 2.50 3.67 -0.67 5 .0 0 -5 .9 9 1 0.83 0.63 0.36 6 .0 0 -6 .9 9 2 1.67 0.06 1.93 7.00 - up 1 0.83 0.00 0.99 32 ( L) , oriental fruit moth Grapholifa molesta (Busck), and cherry fruit worm Grapholila packardi Zeller (Figure 2 and Figure 3). The codling moth is a one o f the m ost important pests in M ichigan apple orchards (Howitt, 1993). The oriental fruit moth is considered as a pest on peach, but can also cause economic injury on apples, mainly during the later part o f the season, when peaches have been harvested. The cherry fruit worm is found in apples sporadically, with cherries and blueberries as its main hosts. Although cherry fruit worm was found in every abandoned orchard, the num ber o f reared adults was very low. The abundance o f lesser appleworm in four Michigan abandoned orchards (Table 2 and Table 3) was much lower than that reported by Glass and Lienk (1971) in New York. These authors found that lesser appleworm injured 72 and 39 % o f fruit during the last two years o f their study respectively, even through in previous years lesser appleworm was not found in the orchard. This may indicate much higher population in NY, but also some o f the differences might by explained by the differences in methods used in each experim ent for detecting the source o f injury. Confusion o f characters o f lesser appleworm injury dates back to the earliest references. M isidentification o f lesser appleworm has been common since it was first found. The most commonly reproduced picture with injured fruit comes from the work o f Simpson (1903), when this author presented it as " injury caused by an unknown caterpillar". Using o f the num ber o f reared adults as an indicator o f fruit infestation, removed possible errors from larvae or injury misidentification. The absence o f lesser appleworm fruit infestation in comm ercially managed orchards suggests that the current control techniques applied in apple system effectively control lesser appleworm. However, the use o f autocidal methods such as m ating 33 60 r ■ L A W 93 40 fnijt Number of infested Douglas abandoned orchard - 1993 H O L M 93 20 B C M 93 22-Jun 1-Aug 15-A ug 2-Scp 16-Scp 30-Scp ! I | Dale 20 r ■ I .AW 93 fruit Number of infested Kalamazoo abandoned orchard - 1993 ■ OFM 93 B C M 93 I-A ug 15-A ug 2-»Sep 16-,Sep 30-Sep , Dale ■ I .AW 93 fruit Number of infested Casnovia abandoned orchard - 1993 S O F M 93 B C M 93 22-Jun 3-Jul 20-Jul t-A u g 15-Aug 2-Sep 16*Sep 30-Sep | ; Date 15 fruit Number of infested Shelby abandoned orchard - 1993 ■ LAW 93 10 S O l-M 93 5 B C M 93 0 22-Jun 3-Jul 20-Jul 1-Aug 15-Aug 2-Sep 16-Sep 30-Sep Dale F ig u re 2. Lesser appleworm (LAW ), oriental fruit moth (OFM ), and codling moth (CM) fruit infestation in Douglas, Kalamazoo, Casnovia, and Shelby abandoned apple orchards during 1993 season. 34 3 0 r■ I.A W 94 fruit Number of infested Douglas abandoned orchard - 1994 Q O F M 94 B C M 94 22-.IU I1 3-Jul 20-.Tul 1-Aug I5-A ug 2-Scp 16-Sep 30-Scp | | j Date 10 ■ LA W 94 fruit Number of infested Kalamazoo abandoned orchard - 1994 5 □ OFM 94 B C M 94 0 20-Jul I-A ug 15-A ug 2-Scp I6-S cp 30-Scp i I ; Date fruit ■ I .AW 94 Q O F M 94 B C M 94 | ! 10 r i Number of infested Casnovia abandoned orchard - 1994 ■ LAW 94 fruit Number of infested Shclbv abandoned orchard - 1994 B O l'M 94 B C M 94 22-Jun F ig u re 3. Lesser appleworm (LAW ), oriental fruit moth (OFM ), and codling m oth (CM ) fruit infestation in Douglas, Kalamazoo, Casnovia, and Shelby abandoned apple orchards during 1994 season. 35 disruption or release o f sterile males to control codling moth, oriental fruit moth or various leafrollers may significantly reduce the num ber o f insecticide sprays made in orchards (Pfeiffer et al. 1993, Carde and Minks 1995). This new situation along with positive changes in the ecosystem, m ight enhance the developm ent o f other insects such as lesser appleworm to become a pest. References Cited: Anonymous, 1922. The m ore im portant apple insects. U S D A, Farmers Bulletin No. 1270, pp: 10-11. Beers, E. H., J. F. Brunner, M. J. W illet& G. M. Warner. 1993. Orchard pest management. A resource book for a Pacific Northwest. Good Fruit Grower, Yakima, WA. Brown, E. E. & S. C. Jones. 1953. The lesser appleworm and its control in Northeastern Oregon. Agricultural Experim ent Station, Circular o f Inform ation 521, Corvallis, OR. Carde, R. T. & A. K. Minks. 1995. Control o f moth pests by mating disruption: successes and constraints. Ann. Rev. Entomol. 40: 559-585. Chapm an, P. J. & S. E. Lienk. 1971. Tortricid fauna o f apple in New York (Lepidoptera: Tortricidae); including an account o f apples’ occurrence in the State, especially as an naturalized plant. New York State Agricultural Experim ent Station, Geneva, NY. CoStat, 1990. Manual revision 4.20. CoHort Software, Berkeley, CA Dean, G. O. & L. M. Peairs. 1913. Insect injurious to fruits. Extension Division, Kansas State Agricultural College, VI(2):61. Eustace, H. J. & R. H. Pettit. 1910. Spray and practice outline for fruit growers. M ichigan State Agricultural College, Experim ent Station, Special Bui. 51. Foster, S. W. & P R. Jones. 1909. Additional observations on the lesser appleworm (Enarm onia prunivora W alsh ). U S D A , Bureau o f Entomology, Bui. 80, Part III. 36 Glass, E. H. & S. E. Lienk. 1971. Apple insect and m ite populations developing after discontinuance o f insecticides. 10- year record. J. Econ. Entomol. 64:23-26. Howitt, A. H. 1993. Common tree fruit pests. M ichigan State U niversity Extension, NCR 63. Keifer, H. H. 1933. The lesser apple worm (G rapholitha prunivora W alsh) in California. J. Econ. Entomol. 26: 509. OEPP, 1979. Data sheets on quarantine organisms. Bulletin OEPP 9(2). Pfeiffer, D. G., W. Kaakeh, J. C. Killian, M. W. Lachance & P. Kirsch. 1993. M ating disruption for control o f damage by codling moth in Virginia apple orchards. Entomol. Exp. Appl. 67: 57-64. Q uaintance, A. L. 1908. The lesser apple worm. U S D A , Bureau o f Entom ology, Bui. 68, Part V. Quaintance, A. L. & W. M. Scott. 1912. The more important insect and fungous enemies o f the fruit and foliage o f the apple. U S D A , Farm ers Bulletin 492. Rivard, I. & M. M ailloux. 1974. Grapholitha prunivora (W alsh) (Lepidopteres: O lethreutidae) dans les pomm eraies du Sud-Ouest du Quebec. Phytoprotection 55:29-32. Roelofs, W. L., A. Comeau & R. Selle. moth. Nature 224: 723. 1969. Sex pheromone o f the oriental fruit Sanderson, E. D., T. J. Headlee & C. Brooks. 1907. Spraying the apple orchard. New Ham pshire College, Agricultural Experim ent Station, Bui. 131. Simpson, C. B. 1903. The codling moth. U S D A, Division o f Entomology, Bui. 41. Sokal, R. R. & F. J. Rohlf. 1981. Biometry. 2nd ed. Freeman, New York W alsh, B. D. 1868. First annual report on the noxious insects o f the State o f Illinois, pp. 78-83. Prairie Farm er Company Steam Print,. Chicago, IL. W ellhouse, W. H. 1920. W ild hawthorn as hosts o f apple, pear and quince pests. J. Econ. Entomol. 13: 388-391. CHAPTER 3 Seasonality of lesser appleworm Grapholita prunivora (Walsh) (Lepidoptera : Tortricidae) in Michigan apple orchards. Introduction Lesser appleworm Grapholita prunivora (W alsh) is noted from all m ajor fruit grow ing areas in morthern U. S. and southern Canada. Together with three other tortricid species: codling moth, Cydiapomonella (L.), oriental fruit moth, Grapholita nioles/a (Busck), and cherry fruitworm, Grapholita packardi Zeller, the lesser appleworm is considered as an important internal fruit feeder (Chapman & Lienk 1971, W eires et al. 1979). Lesser appleworm, as a polyphagous species, can feed on numerous plant hosts, including most cultivated pome and stone fruit (Rivard & M ailloux 1974). In M ichigan and the Pacific Northwest (W ashington, Oregon) lesser appleworm is not considered as an important pest, however the validity o f accurate detection and m onitoring is very important (Howitt 1993, Beers et al. 1993). M onitoring o f pest insects in the field is one o f most important elements o f integrated pest management. Different methods and tools are necessary to observe changes that happen to pest populations. Direct observation in the field is the best way to m onitor insect occurrence, but it is often difficult or almost impossible to accomplish due to problems associated with the identification o f immature stages o f pests or characters o f 37 38 injury. A good example o f the above involves description o f larval stages and fruit injury caused by lesser appleworm and oriental fruit moth (Chapman & Lienk 1971). The use o f sex pherom one trap for detecting insect flight and concept o f day-degree methods may be very useful in monitoring and understanding insect occurrence in the field. The concept that tem perature has a direct effect on growth o f plants and arthropods was formulated as long ago as in the m iddle o f the 18th century (after W ilson & Barnett 1983). Below a certain given tem perature an insect cannot conduct its physiological and biochemical reactions at a high enough rate to support growth. D ifferent insects have different developmental thresholds, but for practical purposes standardized thresholds are used for im portant pests. Pruess (1983) suggested that calculation o f heat unit accumulation above thresholds o f 40, 50, and 60° F ( or 5, 10, 15° C) should be used for degree day accumulations. In exothermic arthropods developm ent rate changes with tem perature o f the environment (Logan et al. 1976). Based on assumptions that the developmental rate is a nonlinear function, with a sim ilar form for m ost insects and that the tem perature in a given area fluctuates predictably from season to season, Taylor (1981) investigated the properties o f the physiological tim e scale for various insects in different temperatures and discussed its evolutionary significance. The use o f a computer-operated Predictive Extension Tim ing Estim ator (PETE) (W elch et al. 1978) was very closely related to the practical use o f a degree day concept. Use o f this interactive m odeling system fed by biological observations together with heat accumulation for specific areas and pests was the basis for predicting the occurrence and importance o f many orchard pests (W elch et al. 1981). In M ichigan, the Fruit Spray C alendar currently uses the average degree day accumulation together with average 39 calendar date for defining correct timing o f insects’ control treatments (Hull et al. 1994). Using pheromone traps for monitoring insect pest populations has proved to be another excellent tool in pest management. Together with the concept o f degree-day accumulation, it can significantly improve the tim ing and effectiveness o f protective techniques. Pherom one traps designed to monitor one species are sometimes useful for monitoring other insects. W ith the high diversity o f apple insect communities (Szentkiralyi & K ozar 1991, Strickler & W halon 1985) it may be very helpful if w e can m onitor and control more than one insect species by using one blend o f pheromone. Attempts to control the whole leafroller complex by mating disruption in European apple orchards by using a single disruptant component proved to be successful and econom ically comparable with pesticide treated control (Carde & M inks 1995). On the other hand, the use o f single com ponent disruptant for m ating disruption o f the leafroller pest complex in Virginia orchards did not work satisfactionary, mainly due to lower effectiveness against one o f leafroller species (Pfeiffer et al. 1993). For accurate prediction o f spring insect emergence from its overw intering sites, it is important to know where we can actually find the diapausing stage. Different overw intering sites o f one species and related with it various times o f em ergence from w inter diapause due to sunshine (heat) exposure may resulted in prolonged first generation emergence. The use o f correctly placed traps with sex pheromone and the correct biofix point can significantly improve pest control (Riedl et al. 1976). In my study I tried to determ ine the importance o f the degree-day concept and pherom one trap catches for predicting lesser appleworm occurrence and seasonality in orchards. To determine an additional factor that may play an important role in tim ing 40 moth occurrence in the field, particularly in the spring, I attempted to identify overw intering sites. Material and Methods Experimental site. D uring the 1992,1993, and 1994 seasons abandoned apple orchards in four fruit growing regions o f Michigan were used for observation o f lesser appleworm seasonality. Sites were located in Douglas, Kalamazoo, Shelby, and Casnovia, MI. (Figure 1). Each o f the orchards was more than 25 years old, with mixed apple varieties. All study orchards were abandoned, with no maintenance activity at least five years prior to the study. There were no pesticides applied in the orchards, except for the Douglas block where fungicides were applied during 1991. Deuree day observation. In the Douglas and Shelby locations degree-days (D D ) at base 50° F and 42° F were calculated during the entire season on computerized w eather stations. A continuous integration method for calculating degree-days accumulation was provided autom atically by EnviroCaster ( Neogen Corporation, Lansing MI). In Shelby degree-day during 1993 and 1994 started to be accum ulated on April 13 and 21 respectively. In Douglas during 1992, 1993, and 1994 the beginning dates were respectively: M arch 04, 06, and 25. Pherom one trap efficacy. D uring 1993 and 1994, sticky traps (Pherocon II, Trece, Inc.) with sex pheromones for codling moth, oriental fruit moth and lesser appleworm were placed 1.5 m high in the orchards and monitored weekly. Three replicates o f each sex pherom one trap for each species were used every year. Groups o f traps for three different insects were separated by approximately 100 m. All collected moths were MICHIGAN SHELBY CASNOVIA DOUGLAS O KALAMAZOO Figure 1. Location o f experimental sites in M ichigan 42 identified and removed from traps. Traps and pherom one lures w ere replaced every 4 weeks. Data were analyzed using one-way analysis o f variance (ANOVA) and H SD Tukey’s test for mean separation (P = 0.05). The total number o f moths collected annually by traps was used as one replication. Overw intering sites: Five methods were used to look for overw intering sites o f lesser appleworm. a) D uring late fall 1992 four metal cone cages per one tree w ere placed under four random ly chosen trees in the Douglas abandoned orchard. Each cage was 1 m diam eter at the base and 90 cm high. A t the top o f each cage a plastic ja r was placed for collecting em erging moths. Traps were checked the following spring, during the first generation flight o f lesser appleworm moths. b) In August o f 1992, 1993, and 1994 corrugated paper was placed on four random ly chosen trees in each abandoned orchard around the trunk and on four scaffold branches. A pproxim ately 10 cm w ide paper bands were placed 1 m high on the trunk and on the branches approxim ately 1.5 m from the trunk. D uring the first year o f the study bands were removed the following April, but because o f bird damage to this sample, during the following years o f observations they were removed in November. c) In April 1994, in the Douglas orchard soil samples w ere collected from under each o f four trees fitted with the paper bands. Four samples o f soil 25 x 50 cm in area and 5 cm deep w ere collected from under each tree w ithout plants and debris and w ere placed in plastic boxes with a mesh top for air circulation. Samples o f weeds and other debris from under the tree were collected in separate containers. The vegetation from 1 m 43 diam eter around the trunk was also collected. Containers with soil (n =16), debris and vegetation (n =16), and vegetation from around the trunk (n = 4) were held at ambient w eather conditions and emerging insects were noted. d) During early April 1994 in the Douglas orchard using the sam e trees that w ere sampled with corrugated paper were also sampled by collecting bark. From one tree, a 25 cm wide strip o f bark was excised from the trunk and inspected for overw intering insect stages. Additionally, a 20 cm strip o f bark from four lower branches o f each tree was inspected for the presence o f lesser appleworm stages. e) On Novem ber 15, 1993 at the Kalamazoo abandoned orchard four samples o f apples rem aining on trees and from under the trees were collected. Two hundred apples (4 x 50) were collected per sample from trees in close proximity. A total o f four samples were collected. Fruit were placed in a growth chamber at 16 : 8 h photoperiod and 24: 16 ° C temperature. Em erging larvae were collected and reared to adults. In w inter o f 1993/94 additional observations were made on 2-3 year old and 5-6 year old branches collected from different parts o f the tree canopy. Branches were removed and inspected in laboratory for presence o f overw intering insects. Results and Discussion. D egree - day observations. In these experiments I used two developmental thresholds to describe lesser appleworm activity using the degree day concept. There is not an established developmental threshold for lesser appleworm. Because o f biology similarities o f this insect with biology o f the codling moth and oriental fruit m oth for my observations I choose DD base 42° F ( as for oriental fruit m oth) and DD base 50° F (as 44 for codling moth) for observations. Over three years o f study in Douglas MI, the lesser appleworm started its first generation flight in the m iddle o f May (Figure 2) with D D 50 accumulation o f 203 - 268. Peak first generation flight occurred at 500 - 636 D D 50. Maximum flight o f the second generation occurred at 1535 - 2128 DD50 (Table 1). In Shelby MI. abandoned orchard during 1993 and 1994 lesser appleworm started its first generation flight at 111 - 241 DD 50 accumulation (Figure 3). The peak o f first generation flight occurred at 259 - 527 DD5(), while the peak o f second generation flight occurred at 1423 - 1787 DD50. During observations at the two locations considerable differences were observed over the three year period. Despite different starting dates for heat accumulation actual DD values between major events also showed a wide range o f differences (Table 2). Three years o f data from the Douglas orchard showed a sm aller difference in total DD accumulation between different years than two years data from Shelby. In New York A gnello et al. (1993) calculated degree day accumulations for numerous orchard pests using a sine wave method. During 5 years o f observation on lesser appleworm they similarly observed a wide gap between major events during different years. W ithout citing the starting point o f degree days accumulation, these authors found first lesser appleworm moths in pheromone traps at an accum ulation o f 82-254 D D 50. Sim ilar differences existed among other major events in lesser appleworm life (Agnello et al. 1993). In my study the big difference in sum o f accumulated degree-days may be related to tim ing o f starting point for heat accumulation. Data from Shelby orchard, specially from 1993, with the lowest D D 50 accumulation, may be biased by the date when calculating o f degree-days started. It is possible that some heat accumulation in the field 16 14 DD 50 F 1500 12 10 1000 8 6 4 2 0 500 \ / 0 .N ? ^ OS’" ^ rfi Douglas, MI 1993 2500 16 14 2000 12 10 500 8 1000 6 4 500 2 0 & ^ o>*> ogDouglas, MI 1994 2500 2000 1500 1000 500 0 Date F ig u re 2. Degree days base 50 F accumulation and lesser appleworm flight seasonality in Douglas, MI abandoned orchard during 1992 - 1994. Degree days base 50 F Average number of moths per trap 2000 LAW Degree days base 50 F Average number of moths per trap Douglas, MI 1992 Degree days base 50 F Average number of moths per trap 45 Table 1. Lesser appleworm life events in comparison with accinniation o f degree days base 42° F and 50° F Degree days accumidations Douglas 1992 18-May 1993 24-May DD42 430 DD50 Peak of 1st gen. Shelby Pange 5/18-5/24 533 1994 23-Ma}’ 414 212 268 date 15-Jwt DD42 1994 18-May Pange 5/18-5/2~ 414-533 1993 2~-May 521 296 296 - 521 203 203-268 241 111 111-241 21-Jioi 20-Jun 6/15-6/21 24-Jrn 1-hm m i -6/24 904 1069 1037 904-1069 1010 541 541-1010 DD50 500 606 636 500-636 527 259 259 - 527 End of date 20-Jul 25-Jul 719-725 29-Jul 29-Jun 1st gat DD42 1656 19-Jul 1889 2007 1656-2007 1967 1153 6/29-729 1153-1967 DD50 989 1201 1325 989-1325 1205 679 679-1205 Peak of date 31-Aug 6-Sep 12-Sep 8/31-9/12 12-Aug ~-Sep 8/12-9/07 2ndgen DD42 2517 3189 3047 2517-3189 2297 2843 2297-2843 DDso 1535 2128 2002 1535-2128 1423 1787 1423-1787 End of date 28-Sep 3026 9/20-9/28 3026-3427 3176 28-Sep 3282 9/18-9/28 DD42 26-Sep 3417 18-Sep 2ndgen 20-Sep 3427 3176-3282 DD50 1843 2264 2244 1843-2264 2016 2069 2016-2069 1st catch date 60 Shelby, Ml 1993 DD 50 F 2500 LAW 50 2000 40 1500 30 1000 20 500 10 0 Degree days base 50 F Average number of moths per trap 47 0 jo 2500 A 50 40 1 \ 30 1 w 20 1 * 10 1 0 2000 i\ l] / 1500 ' — t— ^ 1000 1 r^• L — . / \ '-v. 500 0 j? <& N ^ 4^ c$ Date Figure 3. Degree days base 50 F accum ulation and lesser appleworm LAW flight seasonality in abandoned orchard during 1993 -1994, Shelby, MI. Degree days base 50 F Average number of moths per trap Shelby, Ml 1994 60 Table 2. Lesser applew orm degree days base 42 F and 50 F accum ulation in relation to previous event Insect event d d 42 Degree days accumulation starting f rom previous event Douglas Shelby 1992 1993 1994 Range 1993 1994 Range 430 533 414 4 1 4 -5 3 3 521 296 296-521 d d 50 212 268 203 203 - 268 241 111 111-241 Peak o f D D 42 474 536 623 474 - 623 489 245 245 - 489 1st gen. D D 50 288 338 433 288 - 433 286 148 148 -286 End o f D D 42 752 820 970 752 - 970 957 612 6 1 2 -9 5 7 1st gen. D D 50 489 595 689 489 - 689 678 420 420 - 678 Peak o f D D 42 861 1300 1040 861 -1300 330 1690 330-1690 2nd gen. D D 50 546 927 677 5 4 6 -9 2 7 218 1108 218-1108 End o f D D 42 509 238 370 238 - 509 879 439 439 - 879 2nd gen. D D 50 308 136 242 136-308 593 282 282 - 593 1st catch 49 may already occurred, but was not included. Pheromone trap efficacy. Lesser appleworm sex pheromone traps were able to capture four other moth species: oriental fruit moth, codling moth, obliquebanded leafroller, Choristoneura rosaceana (Harris), and eyespotted bud moth, Spilonota oce liana (Denis and Schiffermuller) (Table 3). The numbers o f captured oriental fruit moth and lesser appleworm males differ significantly (P -- 0.05) from the numbers o f three other species. W hile it was not a surprise that this trap was very effective in attracting the oriental fruit moth, the codling moth and obliquebanded leafroller were probably captured accidentally. Lesser appleworm pherom one traps can be used reliably as a m onitoring tool for oriental fruit moth (Figure 4). The correlation coefficient between num ber o f oriental fruit moths captured in oriental fruit moth traps and num ber o f oriental fruit moths captured in lesser appleworm traps during 1993 and 1994 were r = 0.60 and r = 0.69 respectively. The eyespotted bud moth capture was higher than capture o f obliquebanded leafroller and cherry fruitworm, but these differences were not significant (P = 0.05). Oriental fruit moth sex pheromone traps captured five other species o f moths, all o f them in significantly lower numbers (P = 0.05). Traps for collecting codling moth collected only one other species, the oriental fruit moth. Lesser appleworm and oriental fruit moth share the same component: cis-8dodecenyl acetate (Z8-12:Ac) as their main ingredients o f sex pheromone (Roelofs et al. 1969). The addition o f different optical isomer tram E8-12:Ac is responsible for w ider activity spectrum. Optimum attractant o f oriental fruit moth to Z8-12:Ac requires the addition o f 6 - 7 % o f the tram isomer, while for lesser appleworm it worked best when 2.2 % o f tram isomer was present (Roelofs & Carde 1974). Gentry et al. (1975) by using 50 Table 3. Capture o f differerent moths by sex pheromone traps o f three internal fruit feeding tortricids Captured moths N um ber o f captured m oths T r a p s' / l o c a l i z a t i o n / y c a r OFM Fen. 94 OFM Fen. 93 OFM Doug. 94 LAW Fen. 94 LAW Fen. 93 LAW D oug.94 CM Fen. 94 CM Fen. 93 O FM 2 1138 964 993 198 110 107 10 8 LAW 2 9 6 17 92 162 142 - - CM 2 - 19 1 1 - - 552 452 O B LR2 1 - 1 - - - 1 ESB M 2 6 5 1 5 13 - - CFW 2 - - - - 10 3 - - 1 - Total num ber o f captured moths during the season. Three traps per localization, 2 - OFM - oriental fruit moth G. molesta, LAW - lesser appleworm G. prunivora , CM codling moth C. pomonella , OBLR- obliquebanded leafroller Ch. rosaceana , ESBM eyespotted bud moth S. ocellana, and CFW - cherry fruitworm G. packardi . 51 Average number of mMhs per m p 40 Fennville, MI 1993 OFM traps OFM in LAW traps 30 20 10 0 A Average number of moths per trap 80 Fennville, MI 1994 60 50 40 30 20 A Date F igure 4. Collection o f oriental fruit moths OFM in lesser appleworm LAW pheromone traps in comparison with regular oriental fruit moth traps. Fennville, MI 1993 -1994 52 isomer blends o f 8-dodecenyl acetate were able to capture oriental fruit moth, lesser appleworm , and pecan bud moth, Gretchena boliana (Slingerland), males in the same trap Lesser appleworm was also collected in oriental fruit moth traps by W illson & Tramm el (1980) during their study in New York. Attraction o f lesser appleworm males to pherom ones o f other species with different components: eyespotted bud moth with Z814:OAc, obliquebanded leafroller with complex o f Z1 l-14:O A c, E l l-14:O A c, and Z 1 1H O H , and codling moth with E,E-8,10-12O H (Roelofs & Brown 1982, Arn 1990) was incidental, and capture was not significant. A sim ilar situation was observed by Klun et al. (1973) for European corn borer, Ostrinia imhilalis (Hubner) and redbanded leafroller moth, Aryyrotaenia velulinana (W alker), where the minor quantity o f opposite geometrical isomers in the pheromone lures played an im portant role in attraction o f different moth species. O verw intering sites. During the winters o f 1991/1992. 1992/93, 1993/94 the search for overwintering lesser appleworm larvae included: top layer o f soil under the tree, weeds and debris, bark on trunk and branches, leftover fruit and artificial overw intering sites provided by corrugated paper bands on tree trunk. A fter three years o f observations on multiple sites, no single overw intering lesser appleworm larvae was found. According to old references, lesser appleworm overw inter as a full grow n larva in cocoons formed in cracks and crevices o f the bark, under bark scales and “w herever suitable protection may be found” (Quaintance 1908). Cocoons are m ade o f bits o f surrounding bark and therefore are very “difficult to detect” (Q uaintance 1908). Larvae were also found in paper band around tree trunks, as used for codling moth (Quaintance 53 1908). Brown (1953) found lesser appleworm overw intering sites in cherry orchards in debris on the ground, where them spun cocoon during the fall. Due probably to the life history and length o f stages, lesser appleworm larvae were found also in harvested fruit, where they were able to be active during storage time (Foster & Jones 1909). Larvae w ere found in partly devoured fruit o f hawthorn on the tree and on the soil (Foster & Jones 1909). Overwintering larvae o f lesser appleworm were also found on the ground in the rubbish around the apple bin o f a vinegar factory at the rate o f 4 lesser appleworm larvae to 135 larvae o f codling moth (Foster and Jones 1909). The larvae o f a closely related species, oriental fruit moth, overw inter as full grown larvae on the tree or in the ground beneath the tree. The actual distribution o f overw intering larvae is dependent on many factors such as: tree variety, ripening date, am ount o f rough bark on the tree, or am ount o f weeds and debris on the ground (Steiner 1932). During my observations practically all possible overw intering sites in the orchard w ere sampled extensively. The most intensive search effort was in the Douglas abandoned orchard, where pherom one trap data indicated a high number o f lesser appleworm males. All observations on soil and on trees revealed no stages o f lesser appleworm. The use o f degree-day concept as the only element o f predicting lesser appleworm occurrence is not precise enough. The high variability o f accumulated heat units for the sam e insects life events w ithin the same or between different locations suggests that additional m onitoring factors must be used for accurate prediction o f lesser appleworm life events. Riedl et al. (1976) compared four insect forecasting methods for 54 codling moth and found that degree day and developmental unit sum m ations together with the use o f biofix are the m ost reliable method in predicting the beginning o f first generation egg hatch. In my study, I suspect that at least two additional factors may be involved in the low accuracy o f forecasting the lesser appleworm presence in orchards: a) lack o f data for lesser appleworm physiological thresholds used in predicting lesser appleworm life events and b) the possible variable effects o f overw intering sites affecting lesser appleworm appearance in the spring. References Cited: Agnello, A. M., D. P. Kain, & S. M. Spangler. 1993. Fruit pest events and phenological developm ent according to accumulated heat units. New York Food and Life Sciences Bulletin No. 142, 7p. New York State Agricultural Experim ent Station, Geneva, NY Arn, H. 1990. Sex pheromones. in: Tortricid pests, their biology, natural enemies and control, ed. by: van der Geest L. P. S. & H. H. Evenhuis, Elsevier, Holland, pp: 4 1 3 -4 2 9 Beers, E. H., J. F. Brunner, M. J. Willet, & G. M. Warner. 1993. Orchard pest management. A resource book for the Pacific Northwest. Good Fruit Grower, Yakima, WA, 276 p Brown, E. E. 1953. Life cycle o f lesser apple worm in Northeastern Oregon. J. Econ. Entomol. 46: 163 Carde, R. T. & A. K. Minks. 1995. Control o f moths pests by m ating disruption: successes and constraints. Annu. Rev. Entomol. 40: 559 - 585 Chapman, P. J. & S. E. Lienk. 1971. Tortricid fauna o f apple in New York (Lepidoptera: Tortricidae); including an account o f apples occurrence in the State, especially as a naturalized plant. New York State Agricultural Experimental Station, Geneva, Special Publication, 122p. Foster, S. W. & P. R. Jones. 1909. Additional observations on the lesser apple worm. USDA, B. o f Entomol. Bui. 80, Part III, pp. 45 - 50 Gentry, C. R., M. Beroza, J. L. Blythe, & B. A. Bierl. 1975. Captures o f the oriental 55 fruit moth, the pecan bud moth, and the lesser appleworm in G eorgia field trials with isomeric blends o f 8-dodecenel acetate and air-perm eation trials with the oriental fruit moth pheromone. Eviron. Entomol. 4: 822 - 824 Howitt A. H. 1993. Common tree fruit pests. Michigan State University Extension NCR 63, 252p. Johnson, J. W., J. Hull, & A. L. Jones. 1994. Fruit spraying calendar. Michigan State University. Cooperative Extension Service, Extension Bui. E - 154, 127 p. Klun, J. A., O. L. Chapman, K. C. Mattes, P. W. W ojtkowski, M. Beroza, & P. E. Sonnet. 1973. Insect sex pheromones. minor amount o f opposite geometrical isomer critical to attraction. Science 181: 661 - 662 Logan, J. A., D. J. W ollkind, S. C. Hoyt, & L. K. Tanigoshi. 1976. An analytic model for description o f tem perature dependent rate phenom ena in arthropods. Environ. Entomol. 5: 1133 - 1140 Pfeiffer, D. G., W. Kaakeh, J. C. Killian, M. W. Lachance, & P. Kirsch. 1993. M ating disruption to control damage by leafrollers in Virginia apple orchards. Entomol. Exp. Appl. 67: 47 - 56 Pruess, K. P. 1983. Day-degree methods for pest management. Environ. Entomol. 12: 613 - 619 Quaintance, A. L. 1908 The lesser apple worm. USDA, B. o f Entomol. Bui. 68, Part V, pp. 49-60 Riedl, H., B. A. Croft, & A. J. Howitt. 1976. Forecasting codling moth phenology based on pheromone trap catches and physiological-time models. Can. Entomol. 108: 449 - 460 Rivard, I. & M. Mailloux . 1974. Grapholita prunivora (Walsh) (Lepidopteres: Ole/hreutidae) dans les pommeraies du sud-ouest du Quebec. Phytoprotection 55: 2 9 -3 2 Roelofs, W. L. & R. L. Brown. 1982. Pheromones and evolutionary relationships o f Tortricidae. Ann. Rev. Ecol. Syst. 13: 395 -4 2 2 Roelofs, W. L. & R. T. Carde. 1974. Oriental fruit moth and lesser appleworm attractant mixtures refined. Environ. Entomol. 3: 586 - 589 Roelofs, W. L., A. Comeau, & R. Selle. 1969. Sex pherom one o f the oriental fruit moth. Science 224: 723 Steiner, L. F. 1932. Observations on the distribution o f hibernating oriental fruit worms. J. Econ. Entomol. 25: 864 - 868 56 Strickler, K. & M. W haion. 1985. M icrolepidoptera species composition in M ichigan apple orchards. Environ. Entomol. 14: 486 - 495 Szentkiralyi, F. & F. Kozar. 1991. How many species are there in apple insect communities?: testing the resource diversity and intermediate disturbance hypotheses. Ecol. Entomol. 16: 491 - 503 Taylor, F. 1981. Ecology and evolution o f physiological time in insect. Am. Nat. 117: 123 Weires, R. W., F. J. McNicholas, G. L. Smith, J. F. Schadt, & L. H. Waters. 1979. Reduced spray programs for apple pests in the Champlain and Hudson Valleys. Search (Agriculture) 9(6): 1- 11 Welch, S. M., B. A. Croft, J. F. Brunner, & M. F. Michels. 1978. PETE: an extension phenology modeling system for management o f multi- species pest complex. Environ. Entomol. 7: 487 - 494 Welch, S. M., B. A. Croft, & M. F. Michels. 1981. Validation o f pest management models. Environ. Entomol. 10: 425 -4 3 2 Willson, H. R. & K. Trammel. 1980. Sex pheromone trapping for control o f codling moth, oriental fruit moth, lesser appleworm, and three tortricid leafrollers in a New York apple orchard. J. Econ. Entomol. 73: 291 - 295 W ilson, L. T. & W. W. Barnett. 1983. Degree-days an aid in crop and pest management. Cal. Agr. 37: 4 - 7 CHAPTER 4 Trap efficacy and flight bionomics of lesser appleworm Grapholita prunivora (Walsh) (Lepidoptera : Tortricidae) in Michigan Introduction The traditional use o f broad spectrum pesticides for fruit orchard pest control creates a situation where minor or occasional pests are not normally encountered in the orchard system. The lack o f visible damage provides the illusion that those insects are “ nonexistent” . Recent ecological, biological, and sociological issues associated with wide use o f broad spectrum pesticides in food production has led to the reevaluation o f our dom inant paradigm o f pest management. The developm ent o f semiochemical and other non - chemical alternative control strategies has given hope to w hat M cNeil (1991) calls “ intelligent m anagem ent” programs. This may calm many o f the ecological and sociological fears that are present, but we are still at the beginning o f a long road for common, practical use o f those new technologies. Lesser appleworm Grapholita prunivora (W alsh) is one o f four im portant tortricid species that feed internally on apple fruit. As a native North American species, it is a quarantined insect in Europe and Asia (OEPP 1979). The known host are rosaceous plants mainly cultivated apple, plum, cherry, wild hawthorn and crabapple (Chapm an & 57 58 Lienk 1971, Quaintance 1908, W ellhouse 1920). Lesser appleworm is reported from all main fruit grow ing areas in US and Canada, but it is considered as a pest o f minor importance. In the past the lesser appleworm did not gain much attention as a pest from researchers and practitioners. Due to similarities in seasonal phenology in most fruit grow ing regions and characters o f fruit injury similar to injury caused by codling moth, C ydiapom om lla (L). (Chapman & Lienk 1971, Rivard & M ailloux 1974, H ow itt 1993) or oriental fruit moth, Grapholita molesta (Busck)(W eires et al. 1979), the lesser appleworm was not considered as an economic pest in commercial orchards setting. H ow ever in situations where insecticide use was for some reasons significantly reduced or eliminated, lesser appleworm demonstrated its capacity as a serious pest (Glass & Lienk 1971, W eires et al. 1979). In observations with reduced spray schedules in the Hudson Valley the lesser appleworm was responsible for approximately 50 % o f injuries caused by all internal lepidopterus feeders (W eires et al. 1979). During a 10 year study o f discontinued insecticide use, Glass & Lienk (1971) found lesser appleworm responsible respectively for 72 and 39 percent o f the fruit damage during the last two years o f the study. Recognition o f the potential pest status o f the lesser appleworm began after discovery o f its sex pheromone (Roelofs et al. 1969, Roelofs & Carde 1974). The use o f pherom one traps for detection and m onitoring flight helped in understanding the general flight seasonality o f this insect as well as in better understanding its pest status (Howitt 1993, Beers et al. 1993). For effective monitoring and recommendations for fruit protection we need to 59 understand the life system o f a pest species. The behavioral - ecological approach to the study can be very profitable for pest m anagem ent (McNeil 1991). The behavior o f the insect when in contact with a pheromone plume, and the way an insect enters and escapes the trap or plum e can be different in different species and therefore affect the accuracy o f m onitoring (David & Birch 1985). The availability o f different trap designs forces the question o f which one to use for a specific pest. The analysis o f the effects o f environm ental factors such as temperature and light intensity on daily activity patterns can help in understanding moth behavior in the field (Rothschild & M inks 1974), w hat in consequence will improve fruit protection. My studies started in 1991 to investigate the biology o f lesser appleworm due to its quarantine status in Europe and Japan. With the possibility o f quarantine restrictions, methods for monitoring adult presence in orchards and its practical use were necessary to determine. D uring my studies 1 explored the male lesser appleworm daily activity pattern in apple orchards in relation to sunset and the temperature under the tree canopies. A dditionally, the efficiency o f different trap designs for monitoring lesser appleworm flight were evaluated in field conditions. Materials and Methods Location. During the summers o f 1991- 1993 observations on lesser appleworm flight biology and the efficacy o f six different traps designs were conducted in a 20+ year old abandoned apple orchard in Douglas, MI. There were three dom inant apple varieties : “ Idared”, “Jonathan”, and “Red D elicious”. The orchard where observations took place was located near the border o f the orchard property, surrounded by apple, cherry, pear 60 orchards, and a woodlot. During the study fungicide sprays were applied only in 1991, thereafter, there w ere no pesticide sprays or m aintenance activity in the test orchard. Trap efficacy. During 1991, 1992, and 1993 six different trap designs were assigned for testing: Pherocon I PC (wing) (Zoecon Co.), Pherocon II (diam ond) ( Trece Inc.), Pherocon III (delta), M ultipher I (Bio-Controle), tube trap, and Gypsy moth trap. Evaluated trap designs were baited with LAW sex pherom one lures (Scentry, Inc.) and placed in the orchard. In 1991 traps were placed in orchard in the m iddle o f July, after the flight o f first generation o f lesser appleworm. During 1992 and 1993 traps were placed in the orchard at the beginning o f the May and remained until the end o f flight o f second generation. During 1992 and 1993, the tube trap design which caught the lowest num ber o f lesser appleworm during the previous years was removed from the study, and the remaining trap designs tested as in 1991. Traps were placed in a randomized complete block design, with plots 100 m apart. D uring 1991 and 1992 each trap design was replicated twice, and during 1993 each trap design was replicated three times. Within the block each o f the six different trap designs was located randomly at equal distances around a tree. The position o f the traps w ithin each group was rotated clockwise every week. Traps w ere placed at height 1.51.8 m high (Gentry et al. 1974). Sex pherom one lures and traps w ere changed every four weeks. Traps were checked daily and captured moths removed. Flight biology observation. Using traps from the trap design efficacy studies, observations on lesser appleworm flight biology tim ing and tem perature were done during the first and second generations flights. Each trap was checked for the presence o f male lesser appleworm adults every half hour during late afternoon /early evening from 61 four hours before the sunset to one hour after sunset. The exact time for sunset was obtained from Nautical A lm anac Office, United States Naval Observatory, W ashington, DC. A fter evening observation traps were checked again during the next day morning for detection o f any moth flight during the night hours. During each sam pling interval the num ber o f captured moths and tem perature were noted. The presence o f other species captured in lesser appleworm pheromone traps was also noted. Captured moths were removed from traps and identified. Statistical analysis. Data collected during trap efficacy studies were analyzed using one way analysis o f variance (ANOVA) with randomized complete block design for total trap catch efficacy during each year. Mean trap efficacy was compared using D uncan’s M ultiple range Test (P = 0.05). Due to the different number o f replicates during years for comparison o f three year data, two way ANOVA for completely randomized block and Duncan M ultiple Range Test (P = 0.01) was used for data comparison. Tube trap catch was not included for three-year comparisons. Results and Discussion Under the weather conditions o f Southwest M ichigan lesser appleworm has two generations per year. Flight o f the first generation in 1992 and 1993 started in the beginning o f May with maximum flight during the middle o f June. Flight o f the second generation started in early August, with peak activity during the beginning o f September. The last moths were collected in late September ( Figure 1). Data from the 1991 season are not available because o f misidentifications o f moth captured during the flight o f the first generation. 16 - - 1993 - 1 9 9 2 Number of moths per trap 14 12 10 8 6 4 2 0 £ $ Date F igure 1. Lesser appleworm flight seasonality during 1992 and 1993 in the abandoned apple orchard, Douglas, M I . 63 During the study significantly different numbers o f adult moth were observed in pherom one traps each year (F = 4 43; d f =2, 4; P = 0.0255) (Figure 2). The highest num ber o f lesser appleworm (499 males) was observed in 1991. During 1992 and 1993 few er lesser appleworm adults w ere caught: 169 and 216 respectively. The difference in numbers o f collected moths among years is difficult to explain. Some o f possible reasons may include different w eather patterns during those summers, with summers o f 1992 and 1993 colder than o f 1991. In 1993 trees had additionally a very light crop, compared to the previous two years, due to early season frost damage. During all three years o f study trap x year interaction was not significant (P = 0.0822). Effects o f diurnal litzht periods and tem perature on fliuht. Lesser appleworm moth flight activity was observed at tem peratures from 18 °C to 25 °C (64 - 76 °F) (Figure 3). In tem peratures below and above those thresholds lesser appleworm males were observed very sporadically. There was no observable lesser appleworm moth flight at tem peratures below 17 °C (62 °F) ( Figure 3). Flight threshold temperatures for the lesser appleworm are higher than for codling moth or oriental fruit moths. Batiste et al. (1973) reported that adults codling moth were not attracted to pheromone when the tem perature was below 13 °C or above 27 °C. During my observations, no lesser appleworm moths were caught at tem perature above 29 °C (82 F). Observations o f crepuscular flight showed that lesser appleworm flight activity was limited to only late afternoon and early evening hours, starting 3 hours before sunset and ending no later than 30 minutes after sunset (Figure 4). I found no lesser appleworm flying activity during the night or during full day light. During 1992 - 1994 lesser appleworm was never collected by using UV light traps (R. Kriegel, per com. 1994). E3Pherocon I [□Pherocon II E2Gypsy MothDelta E lM ulti Pher Moths \ trap \ season 8 o 00 o CD o w .w 1991 1992 1993 Figure 2. Comparison of average number of lesser appleworm moths captured per trap during the season. In 1991 data were collected only during the flight of second generation o f lesser appleworm (after July 15). E3LAVV □LAW Temperature F POFM 50 0 10 20 30 40 Number of captured male moths Figure 3. Lesser appleworm (LAW) and oriental fruit moth (OFM) flight pattern in relation to ambient temperature. Data collected in abandoned apple orchard, using of Pherocone II traps and LAW sex pheromone during 1991-1993, Douglas, MI. minutes QLAV\f 1991 □LAW 1992 -180 □LAW 1993 ®OEM 1991 □OFM 1992 BOFM1993 Time before and after sunset -150 -120 -90 -60 -30 0 30 250 200 150 100 50 0 20 40 60 80 Number of captured male moths Figure 4. Crepuscular flight of lesser appleworm (LAW) and oriental fruit moth (OFM). Data collected in abandoned apple orchard, using Pherocone II traps and the lesser appleworm sex pheromone during 1991 1993, Douglas, MI. 100 67 The highest num ber o f moths was observed 120 min to 60 min before sunset. Lesser appleworm moths observed by Gentry et al. (1975) in Georgia also terminated flight activity always before dark (9 p.m.). My observations showed that during the days with higher tem peratures lesser appleworm males tended to start flying later in the day, but earlier on days with cooler temperatures. A sim ilar trend was observed in codling moth flight (Castrovillo and Carde 1979), cabbage Iooper, Trichophisia ni (H bn.)( Sower at al. 1971), lesser peach tree borer, Synanlhedonpictipes (Grote & Robinson) (Gorsuch et al. 1975), and spruce budworm, Choristomura finmferana (Clem .) (Sanders & Lucuik 1972). For Argym/aenia vdutiana (W alker) and five other Lepidoptera species Comeau et al. (1976) found that the diel periodicity was modified by ambient temperature. Comparison o f different trap desiuns for capturing males o f lesser applew orm . Com paring the six trap designs for m onitoring flight, the Pherocon II trap captured the highest number o f adult lesser appleworm males (Table 1). Although Pherocon 1 CP, M ultiplier and Delta trap designs caught significantly lower number o f moths (P =0.01) they are also useful for monitoring lesser appleworm flight. The Gypsy moth trap every year showed the lowest number o f captured males o f lesser appleworm except in 1991, when tube trap was included in observations. The tube trap was removed from observation after 1991 due to very low moth capture. Trap choice plays an important role in monitoring insect activity in the field. Beroza et al. (1 9 7 3 ), Lewis & M acaulay (1976) and many other authors (see references in Carde 1979) discuss the importance o f the right trap design for accurate monitoring. D uring a pherom one trap efficacy study on oriental fruit moth and lesser appleworm, Gentry et al. (1975) found that the Pherocon 1CP trap design caught the highest num ber 68 T ab le 1. Comparison o f six pheromone trap designs for capturing males o f lesser appleworm. Data collected in Douglas, MI abandoned orchard during 1991 -1993 Trap design N um ber o f collected lesser appleworm moths per trap design / season 1991 1993 1992 1991 - 1993 Pherocon II 120 a 100 a 73.7 a 94.42 a Pherocon I 68.5 ab 53.5 b 47 55.28 b Delta trap 46 a 19.5 b 63.7 ab 46.00 be 13.3 c 41.71 be 11 20.85 c Multi pher trap 74 ab 52 Gypsy moth trap 25 b 31.5 b Tube trap 21 b n/a b n/a b c n/a Means in the same column followed by the same letter are not significantly different at P = 0.05 Duncan Multiple Range Test 69 o f oriental fruit moth They did not have the Pherocon II trap in the observations. Lewis & M acaulay (1976) during a study on traps for pea moth, Cycfia nigricana (Steph.) examined the effect o f trap design on the pherom one plume shape emitted and its resulting effects on trap catch. The triangular shaped trap, that resembles the Pherocon II traps, caught the most moths. Because o f this and the ease in servicing this trap, it is now the most commonly used trap in apple IPM programs (Johnson & Herr 1995). D uring this study additional data were also collected on the flight biology o f oriental fruit moth. Using the same traps and pheromone for lesser appleworm I collected specim ens o f both species. This is not surprising since both species share the sam e main com ponent o f their sex pheromone: c7.v-8-dodecenyl acetate (c8-12:Ac) (Roelofs et al. 1969). The optimum m ixture for capturing lesser appleworm male contains 2.2 percent o f tra m isomer, w hile for oriental fruit moth the optimum percentage o f trans isom er is 6.4 percent (Roelofs & Carde 1974). Linn and Roelofs (1989) using oriental fruit moth as an example, discussed the importance o f each component in the m ulticom ponent blend o f pheromones. M inimal changes in the cis / tram ratio o f isomers changed significantly the level o f male response. The similarity between the sex pheromone o f those two species allowed the collection o f additional data about oriental fruit moth flight pattern by using only lesser appleworm pheromones. D uring 1991, 1992, and 1993 I caught 182, 137, and 17 males o f oriental fruit moth. Gentry et al. (1974) used different blends o f oriental fruit moth pherom one and captured numerous males o f lesser appleworm when the concentration o f E (tram ) isomer was 2.5 -7.5%. In other study Gentry et al. (1975) also collected pecan bud moth, Gretchena bolliaiia (Slingerland), using the oriental fruit moth pheromone. In 70 my tests using com m ercially available oriental fruit moth pheromone (Trece, Inc.) I did not capture males o f lesser appleworm, which suggests a slight difference in the mixture o f the lure used in this study. Oriental fruit moth males started flight at a lower tem perature than lesser appleworm (Figure 3). A tem perature below 17 °C was not a barrier for moth activity. Rothschild & M inks (1974) in their study in Australia did not capture oriental fruit moth when tem perature was below 15 °C. In Europe the lower flight activity threshold is 11 °C (Roehrich, 1961). Under my study conditions the highest trap catch occurred in tem peratures from 18 °C to 22 °C. In temperatures above and below this range, I observed a significantly lower num ber o f oriental fruit moth. Rothschild & M inks (1974) did not observe tem perature dependency in their work, and suggested rather that flight appeared to be an “all” or “ nothing” activity above or below the threshold. Further investigation are necessary to determ ine the reason that oriental fruit moth males were captured in this study. One o f possibilities may include suggestion, that the release o f the pherom one is mediated by temperature, and different ratios o f cisltrans isomers are released at different temperatures. The oriental fruit moth started flight at similar intervals before sunset as the lesser appleworm, but 69.6 percent o f the males w ere captured during the 90 minutes before sunset (Figure 3 and Figure 4). Out o f all captured oriental fruit moth males 17.8 percent were captured 30 min. and m ore after sunset. Rothschild and Minks analysis (1974) showed that flight is prim arily related to sunset time, but may also be m odified by temperature. Under their conditions, activity began at 150 min before sunset and peaked at 60 min before sunset to shortly after sunset. Gentry et al. (1975) did not relate their 71 data to sunset but showed that oriental fruit moth activity started before that o f lesser appleworm and lasted longer into the night, with some captures between 3 - 5 am. Am ong available varieties o f pheromone trap designs Pherocon II and Pherocon I proved to be the most useful and accurate for lesser appleworm flight m onitoring. Other types o f trap w ere not as useful for accurate moth observations. By using the daily pattern o f lesser appleworm flight activity in relation to light intensity and tem perature m ore accurate monitoring programs can be developed. During the length o f study, observation on flight pattern also proved to be very useful for successful m aintaining o f moths colony. References Cited: Batiste, W. C., W. H. Olson, & A. Berlowitz. 1973. Codling moth: diel periodicity o f catch in synthetic sex attractant vs. female- baited traps. Environ. Entomol. 2: 673-676. Beers, E. H., J. F. Brunner, M. J. Willet, & G. M. Warner. 1993. Orchard pest management. A resource book for the Pacific Northwest. Good Fruit Grower, Yakima, WA, 276 p Beroza, M., C. R. Gentry, J. L. Blythe, & G. M. Muschik. 1973. Isomer content and other factors influencing captures o f oriental fruit moth by synthetic pherom one traps. J. Econ. Entomol. 66: 1307-1311. Carde, R. T. 1979. Behavioral responses o f moths to fem ale-produced pherom ones and the utilization o f attractant-baited traps for population monitoring. In: M ovem ent o f highly mobile insects: concepts and m ethodology in research. Edited by: Rabb, R. L. & G. G. Kennedy. North Carolina State University pp.: 286 - 3 15 Castrovillo, P. J. & R. T. Carde. 1979. Environmental regulation o f fem ale calling and m ale pheromone response periodicity’s in the codling moth (Laspeyresia pomonella). J. Insect Physiol. 25: 659-667. Chapman, P. J. & S. E. Lienk. 1971. Tortricid fauna o f apple in New York (Lepidoptera: Tortricidae); including an accounts o f apples' occurrence in the State, especially as a 72 naturalized plant. New York State Agricultural Experimental Station, Geneva, Special Publication, 122p. Comeau, A., R. T. Carde & W. L. Roelofs. 1976. Relationship o f ambient tem peratures to diel periodicity’s o f sex attraction in six species o f Lepidoptera. Can. Ent. 108: 415-418. David, C. T. & M. C. Birch. 1985. Pheromones and insect behavior. In: Jutsum, A. R. & R. F. S. Gordon eds. Insect pheromones and plant protection. John Willey. Chichester, UK. pp.: 17-35 Gentry, C. R., M. Beroza, J. L. Blythe, & B. A. Bierl. 1974. Efficacy trials with the pherom one o f the oriental fruit moth and data on the lesser apple worm. J. Econ. Entomol. 67: 607-609. Gentry, C. R., M. Beroza, J. L. Blythe, & B. A. Bierl. 1975. Captures o f the oriental fruit moth, the pecan bud moth, and the lesser appleworm in Georgia field trials with isomeric blends o f 8-dodecenyl acetate and air-perm eation trials with the oriental fruit moth pheromone. Environ. Entomol. 4: 822-824. Glass, E. H. & S. E. Lienk. 1971. Apple insects and mite populations developing after discountenance o f insecticides: 10-year record. J. Econ. Entomol. 64: 2326. Gorsuch, C. S., M. G. Karandinos, & C. F. Koval. 1975. Daily rhythm o f Synanthedon piclipes (Lepidoptera: Aegeridae) female calling behavior in Wisconsin: temperature effect. Ent. Exp. & Appl. 18: 367-376. Howitt, A. H. 1993. Common tree fruit pests. Michigan State University Extension NCR 63, 252 p. Johnson, J. W. & M. Herr. 1995. Apple insects scouting manual. Great Lakes Publishers. Sparta, MI. pp. Lewis, T. & E. D. M. Macaulay. 1976. design and elevation o f sex-attractant traps for pea moth Cydia nigriccma (Steph.) and the effect o f plume shape on catches. Ecol. Ent. 1: 175-187. Linn, C. E. & W. L. Roelofs. 1989. Response specificity o f m ale moths to m ulticom ponent pheromones. Chemical Senses 14: 421-437. M cNeil, J. N. 1991. Behavioral ecology o f pheromone-mediated comm unication in moths and its importance in the use o f pheromone traps. Annu. Rev. Entomol. 36. 407 - 430 OEPP, . 1979. Data sheets on quarantine organisms. EPPO List A l. European and 73 Mediterranean Plant Protection Organization 9(2): 1-7 Quaintance, A. L. 1908. The lesser apple worm. U. S. Department o f Agriculture, Bureau o f Entomology. Bulletin No. 68, Part V. Washington 1908. Rivard, I. & M Mailloux . 1974. Grapholita prtmivora (Walsh) (/ jepidnptercs: Olethreutidae) dans les pommeraies du sud-ouest du Quebec. Phytoprotection 55: 29-32. Roehrich, R. 1961. Contribution a I’etude ecologique des populations de la Tordeuse du Pecher (Grapholilha molesta Busck) dans la region Aquitaine. Ann. Epiphyt. (Paris) 12: 1 - 114 Roelofs, W. L. & R. T. Carde. 1974. Oriental fruit moth and lesser appleworm attractant mixtures refined. Enwiron. Entomol. 3: 586-588. Roelofs, W. L., A. Comeau, & R. Selle. 1969. Sex pherom one o f oriental fruit moth. Nature 224: 723 Rothschild, G. H. L. & A. K. Minks. 1974. Tim e o f activity o f male oriental fruit moths at pherom one sources in the field. Environ. Entomol. 3: 1003-1007. Sanders, C. A. & G. S. Lucuik. 1972. Factors affecting calling by female eastern spruce budworm, Choristoneura fumiferana (Lepidoptera : Tortricidae). Can. Ent. 104: 1751- 1762 Sower, L. L., H. IT Shorey & L. K. Gaston. 1971. Sex pherom one o f noctuid moths. XXI. Light: dark cycle regulation and light inhibition o f sex pherom one release by females o f Trichoplusia ni. Ann. Ent. Soc. Am. 64: 488 - 492 W eires, R. W., F. J. M cNicholas, G. L. Smith, J. F. Schadt, & L. H. W aters. 1979. Reduced spray programs for apple pests in the Champlain and Hudson Valleys. Search (Agriculture) 9:1-11. Wellhouse, W. H. 1920. Wild hawthorns as a host o f apple, pear and quince pests. J. Econ. Entomol. 13: 388-391. CHAPTER 5 Lesser appleworm Grapholita prunivora (Walsh) (Lepidoptera : Tortricidae) oviposition preference and female fecundity when reared in laboratory Introduction Lesser appleworm, Grapholita prunivora (W alsh) (Lepidoptera : Tortricidae) belongs to a group o f pests whose larvae are internal fruit feeders. This species, an indigenous North American insect, is reported from all o f the most important pome fruit grow ing areas o f United States and Canada. Larvae o f lesser appleworm can be com m only found in abandoned apple orchards, but rarely in comm ercially protected blocks (Beers et al. 1993, Howitt 1993). Larvae feed mainly on fruit o f rosaceous plants including: cultivated apples, pears, peaches, plums and on wild hawthorns, crabapples, and roses (Chapman & Lienk 1971, Quaintance 1908). Due to its low economic significance lesser appleworm tends to be classified as a secondary or even accidental pest in orchards. According to C hapm an’s (1973) classification o f host categories, apples appears to be the prim ary host for this pest. Lesser appleworm adults use apple fruit as an oviposition site and em erged larvae are able to com plete their developm ent by using only this food source (Chapman 1973). The current host range o f lesser appleworm suggests that before the introduction 74 75 o f cultivated apple into North America, hawthorn and crabapple w ere probably used as the prim ary hosts. After introduction o f apples to North America , about tw enty native tortricid species switched to apples and used it as a main host (Chapman 1973). W ithin the Rosaceae family, apples are the most closely related cultivated fruit to native crabapple and hawthorns (Chapman & Lienk 1971). The close botanical relationship, sim ilarity in habitat, and abundance o f cultivated trees w ere probably the main factors for exploiting them as a feeding and oviposition site (W ellhouse 1920) Ovipositional preference o f different fem ale insects species has been studied extensively during last years. Behavioral, genetic, and ecological factors are important determ inants in insect oviposition behavior ( Thompson & Pellm yr 1991). Overviews o f the most recent research developm ents can be found in Browne (1993), Thom pson & Pellm yr (1991), Jaenike (1990), Renwick (1989), and Courtney et al. (1989). The objective o f this study was to determine the oviposition preference o f lesser appleworm, using two com m ercially grown and one natural host plant in a sim ultaneous choice experiment. I also evaluated the num ber o f the offspring per single female when limited choices o f ovipositional sites were available. Materials and Methods During the sum m er o f 1994 a lesser appleworm colonies was established from adults reared out o f apple fruit collected from four different abandoned orchards. Fresh “Red D elicious” and “Golden D elicious” apples varieties were used as the main larval food for m aintaining the lesser appleworm colony in the laboratory. For testing lesser appleworm oviposition preference between two cultivated and one wild 76 hosts, a sim ultaneous choice experim ent was designed as referred by Singer (1986). D uring July and August fruits from apples (var. “M cIntosh’ ), plums (var. “ Stanley”) and wild hawthorn w ere collected and used for testing lesser appleworm oviposition preference. During the experim ent seven different combination o f fruits were tested: 1) apples, 2) plums, 3) hawthorns, 4) apples plus plums, 5) apples plus hawthorns, 6) plums plus hawthorns, and 7) apples plus plums plus hawthorns. Fruits w ere placed in clear 40.3 cm L x 27.7 cm W x 15.1 cm H plastic boxes (Sterilite Corp. USA) covered with mesh top lids. In various treatm ent combinations three fruits o f apples, plums or/and hawthorn clusters ( 8 - 1 2 fruit per cluster) were attached to box bottom with double stick magic tape (Scotch Corp. USA). The design o f the assays is shown in Figure 1. All com binations were designed to be replicated four times and performed twice: in July and in August. Due to fem ale m ortality after release into cages, the second series o f experim ents (in August) contained only three replications o f each combination. At the beginning o f the experim ent one male and one female adult lesser appleworm were released into each box. W ater and food were provided in two small plastic containers with cotton dipped in a) water and b) honey diluted by water and placed in every box. W ater was added every day to both food containers. Adult moths released into the boxes were a maximum o f two days old, and w ere obtained from a laboratory colony. Boxes with fruit and adult moths were placed in outside conditions (ambient tem perature, daylength) but w ere protected against rain. A fter two to four weeks all fruits w ere examined for the total num ber o f eggs laid and emerged larvae. D ue to the gradual 77 ---------------- .....................- ©<->® n ® □ ® « n a) ® ® *(x) < ~ — >:*). r—i 1__i □ ® ,-» © 1[ -Ji (y) b) r * © c) @ - fruit assig n m en t inside th e box I j - p lacem en t of containers with w ater an d honey an d w ater Figure 1. Position o f fruit inside the boxes: a) one host design, b) two hosts design, c) three hosts design. Arrows indicated changed positions o f fruit within replications. availability o f lesser appleworm male and female adults, the duration o f different com binations and replications varies. Exact dates are shown in Table 1. Results were collected by counting number o f emerged larvae and num ber o f non hatched eggs. Data were compared by the use o f an index o f preference as described by Tabashnik et al. (1981) (modified by author for experiment): number of larvae and eggs collected from x / o r y I or z Index of preferenceium^cr jarva CggS colected from x / y / z / and x / y / x *^ /“ a) depending on combinations In the above index values close to 50% show no preference, below 50% show a tendency to prefer alternate host(s), and above 50 % suggest the tested fruit is preferred as an ovipositional site for lesser appleworm. Table 1. Starting and ending dates for first and second series replications o f lesser appleworm oviposition preference experiment. Dates First series C om bination Rep, 1 Rep. 2 Rep. 3 Second series Rep.4 Rep. 1 Rep. 2 Rep.3 1. A pples Start End 30-Jul 25-Aug 30-Jul 25-Aug 30-Jul 25-Aug 30-Jul 25-Aug 20-Aug 10-Sep 20-Aug 10-Sep 20-Aug 10-Sep 2. P lum s Start End 6-Aug 25-Aug 8-Aug 25-Aug 6-Aug 25-Aug 8-Aug 25-Aug 13-Aug 10-Sep 23-Aug 10-Sep 23-Aug 10-Sep 3. H aw thorn Start End 8-Aug 25-Aug 8-Aug 25-Aug 8-Aug 25-Aug 8-Aug 25-Aug 20-Aug 10-Sep 20-Aug 10-Sep 20-Aug 10-Sep 4. A p p les + P lum s Start End 28-Jul 25-Aug 28-Jul 25-Aug 28-Jul 25-Aug 28-Jul 25-Aug 26-Aug 10-Sep 26-Aug 10-Sep 26-Aug 10-Sep 5. A p p les + Hawt. Start End 8-Aug 25-Aug 2-Aug 25-Aug 2-Aug 25-Aug 8-Aug 25-Aug 18-Aug 10-Sep 18-Aug 10-Sep 18-Aug 10-Sep 6. P lum s + Hawt. Start End 2-Aug 25-Aug 9-Aug 25-Aug 10-Aug 25-Aug 8-Aug 25-Aug 18-Aug 10-Sep 18-Aug 10-Sep 18-Aug 10-Sep 7. A pp.+PI.+ Hawt. Start End 30-Jul 25-Aug 2-Aug 25-Aug 2-Aug 25-Aug 2-Aug 25-Aug 24-Aug 10-Sep 24-Aug 10-Sep 24-Aug 10-Sep 79 The indices o f difference in number o f eggs laid between series and among different combinations w ere subjected to analysis o f variance (ANOVA) and Tukey’s HSD (T-M ethod) tests ( P = 0.05). For comparison o f numbers o f lesser appleworm progeny in the presence o f specific food categories within series, analysis o f variance (ANOVA) and SNK test ( P=0.05) were used. The observations o f total number o f eggs per one female w ere also analyzed and the K olm ogorow - Smirnow test was used for testing the norm ality o f the observed frequency distribution (Sokal & R ohlf 1981). R e su lts a n d d iscu ssio n . This study was based on the assumption that insect females when exposed to many potential hosts will show a hierarchy in their preference (Thom pson & Pallm yr 1991, Beach & Todd 1988, Sharma & Norris 1991). Use o f simultaneous choice trials permitted for lowering the bias from variation in oviposition preference that may occur am ong females (Tabashnik et al. 1981). The mean number and range o f progeny o f lesser appleworm in the different treatm ent combinations o f fruit are shown in Table 2. During the first series o f experiments the highest num ber o f lesser appleworm larvae and eggs w ere found in the combination including apples and plums. Trials o f plums, hawthorns, apples plus hawthorns, apples plus plums, and apples plus plums plus hawthorns did not show a significant difference in observed female fecundity. Females in treatm ent com binations o f apples alone, and plums plus hawthorns laid significantly (P <0.05) lower num bers o f eggs than in the apples plus plums treatment combination. During the second series o f Table 2. Oviposition preference by lesser appleworm in simultaneus choice experiment. C om bination First series Second series2 Total M ean ± SEM Significance4 Range 1. Apples 10.75 ±12.47 b 0-23 9.00 ±5.13 a Range 6-14 2. Plum s 16.25 ± 10.28 ab 4-27 1.00 ± 1.00 a 0 -2 3. H aw thorn 21.75 ±5. 97 ab 13-26 9.67 ±2.88 a 8-13 4. A pple 19.25 ± 15.50 a 3-39 11.67 ± 17.67 a 0-32 16.00 ± 14.36 5-41 1.67 ± 2.89 0 -5 11.71 ± 14.47 3-25 6.67 ±9.87 1-22 5.00 ± 7.00 1 -3 0.67 ± 0.57 3-13 3.00 ±3.00 Plum 19.25 ±15.37 5. A pples 12.50 ± 9.47 Haw thorn 6. Plum s Haw thorn ab 11.75 ± 8.92 2.00 ± 0.82 6.75 ± 4.35 7. A pple 12.00 ± 6.63 Plum s Haw thorn b M ean ± SEM Significance4 a a M ean ± SEM 10.00 ±9. 22 9.72 ± 10.93 16.57 ±7.89 0-18 10.00 ±9.33 0-13 8.86 ± 8.32 0 -1 1.43 ± 0.98 0 -6 5.14 ±4.06 3-19 2.33 ± 2.08 0 -4 7.85 ± 7.08 4.50 ± 3.11 2 -9 3.00 ± 2.00 1 -5 4.00 ±2. 58 7.75 ± 3.59 3-11 4.33 ± 0.58 4 -5 6.86 ±3.63 ab 1- data from 4 replications 2- data from 3 replication a -caltulated for cumulative data for all fruit in combination a 81 experim ents significant differences (P < 0.05) among treatm ent combinations w ere not observed. At the same tim e there were significant (P < 0.05) differences in fem ale fecundity between the first and second series experiments (Figure 2). The lack o f significant differences among treatm ent combination during the second series experim ent may be a result o f many factors. This second series was conducted later during the summer, when atm ospheric conditions were different. M aturity difference o f fresh fruit that was used in the two experiments may also be important. Jaenike (1990) showed that the chemical structure o f plants may play an important role in determ ining its usability and exploration by insects. Among the four treatm ent combinations that included apples as one o f the offered ovipositional sites (Table 3), only apples in com bination with hawthorns during the first and second series experiments, and with plums during second series experiments were preferred as an ovipositional site. Given a choice among two other possible sites, apples alone w ere significantly (P < 0.05) not preferred by lesser appleworm females. Plums w ere chosen predom inantly over other fruit only in combination with apples, but the level o f preference was low. Plums in both series were a non - preferred ovipositional site when hawthorns, or apples plus hawthorn alternatives were available (Table 3). Significantly more (P < 0.05) larvae and eggs were observed during both series on hawthorn fruit compared to plums when those were the only choice. In the sam e tim e hawthorns was not preferred as an ovipositional site when apples w ere present. In a hawthorns plus apples plus plums combination indexes o f preference for hawthorns were 33.38 % and 51.9 %. A sim ilar lack o f strong ovipositional preference was demonstrated by the butterfly Colias eurytheme (Tabashnik et al. 1981), soybean looper, Pseudoplusia 25 Mean number of progeny 20 15 10 oo N) First series Second series Figure 2. Comparison of mean number of lesser appleworm progeny per combination during first and second series experiments I 83 T ab le 3. Indexes o f preferences for lesser appleworm oviposition on three different hosts. C o m b in atio n 1 a) Apples a F irst series 100 a c Second series 100a 1 b) Apples + Plums 47.28 b 78.83 ab 1 c) Apples + Hawthorn 54.75 b 52.70 ab 1 d) Apples + Plums + Hawthorn 47.60 b 19.53 b 100 a 100 a 2 b) Plums + Apples 52.72 b 21.17 a 2 c) Plums + Hawthorn 25.20 c 38.07 a 2 d) Plums 4- Apples + Hawthorn 19.03 c 28.57 a 100 a 100 a 3 b) Hawthorn + Apples 45.50 be 47.30 a 3 c) Hawthorn + Plums 74.78 ab 61.90 a 3 d) Hawthorn + Apples + Plums 33.38 c 51.90 a 2 a) Plums 3 a) Hawthorn c a - in an italics - host for com parison b- data analysed used anlysis o f variance (ANOVA) and T ukey’s (HSD) test at P < 0.05 c - when no eggs were laid no preference was assumed (index o f preference = 5 0 % ) 84 includcns (W alker) (Beach & Todd 1988) and by beet armyworm, Spodoptera exigna (Hiibner) on cultivars o f chrysanthemum (Yoshida & Parrella 1991). Insects use wide arrays o f stimuli for choosing possible oviposition site. For example, females o f codling moth, Cydiapomonella (L.), commonly known fruit pest, during their search for an ovipositional site will m ore likely oviposit on fruit that have some level o f alpha farnesene isomer than on fruit without it (W earing & Hutchins 1973). There are no data available in the literature indicating which factor(s) may lead lesser appleworm females in their choice o f ovipositional site. The results show that lesser appleworm will accept cultivated hosts as well as wild ones. The data did not answer the question o f which factors played the most important role in host discrimination for lesser appleworm. Small arena size may have had a negative impact on the importance o f prealighting host discrimination by females (Renwick 1989). Recognition and acceptance o f the host plant by gravid females after landing depends on numerous physical and chemical stimuli such as surface structure or presence o f specific chemical compounds (Renwick & Chew 1994). Hawthorn, which has served as a native host for lesser appleworm (Chapman & Lienk 1971, W ellhouse 1920) for many years appears to be preferred over plums. The use o f apples as larval food during colony rearing may have had some effect on female choice between different hosts and apples. An insect’s previous experience from larval stage may be important for acceptance o f oviposition site. One o f North A m erica’s the most important native apple pests, the apple maggot Rhcigoletispomonella (W alsh), will more likely oviposite on a fruit type with which it has previous experience (Papaj & Prokopy 1988). 85 Single females used for observations laid different numbers o f eggs. In two replications during first series o f experiments and in two replications during the second series, no single egg or larva was observed on the fruit. O f the rem aining females (n = 45) that oviposited during the experim ent 64.4 percent (n = 29) laid less than 16 eggs The highest observed num ber o f eggs per single fem ale was 64. There is no information in the literature about possible lesser appleworm fem ale fecundity. In the old literature Quaintance (1908), Foster & Jones (1909), and Taylor (1909) m entioned fruit surface as a preferred ovipositional site; however, no data on the number o f eggs per single female was mentioned. Figure 3 shows the frequency o f eggs per single fem ale and the results o f a test for normality o f distribution. More research is needed on the evaluation o f food preference and larval perform ance o f lesser appleworm on different hosts. No-choice trials with many different hosts may contribute to a better understanding o f adult ovipositional preference. Sequential choice trials which allow insects to make contact with more than one host, which may more closely reflect what naturally happens during the host search behavior (Singer 1986), may explain the complexities o f lesser appleworm oviposition behavior m ore thoroughly. In the real orchard situations, when only cultivated hosts are available, lesser appleworm will likely use them for completing development. The presence o f hawthorn trees in the surrounding areas may have an effect on lesser appleworm performance. Rely on conditions, lesser appleworm may choose its host. M onocultural abundance o f orchard fruits may turn a wild hawthorn insect population into a fruit pest. Presently, this situation is probably avoided by the use o f chemical control o f orchard pests. However, 0 5 10 15 20 25 30 35 40 45 50 55 60 Number of progeny per single female Figure 3. Frequency histogram of lesser appleworm Grapholita prunivora (Walsh) females fecundity when reared in simultaneous choice situation 87 use o f non-chemical methods for fruit pest control may invite insects such as the lesser appleworm to benefit from this new available space. References Cited: Beach, R. M. & J. W. Todd. 1988. Oviposition preference o f the soybean looper (Lepidoptera : N octuidae) among four soybean genotypes differing in larval resistance. J. Econ. Entomol. 81: 344 -348 Beers, E. H., J. F. Brunner, M. J Willet, & G. M. Warner. 1993. Orchard pest management. A resource book for the Pacific Northwest. Good Fruit Grower, Yakima, WA, 276 p. Browne, L. B. 1993. Physiologically induced changes in resource - oriented behavior. Ann. Rev. Entomol. 38: 1 - 25 Chapman, P. J. 1973. Bionomics o f the apple - feeding Tortricidae. Ann. Rev. Entomol. 18:73 - 96 Chapman, P. J. & S. E. Lienk. 1971. Tortricid fauna o f apple in New York (Lepidoptera: Tortricidae); including an accounts o f apples' occurrence in the State, especially as a naturalized plant. New York State Agricultural Experimental Station, Geneva, Special Publication, 122p. Courtney, S. P., G. K. Chen & A. Gardner. 1989. A general model for individual host selection. Oikos 55: 55 - 65 Howitt, A. H. 1993. Common tree fruit pests. Michigan State University Extension NCR 63, 252p. Foster, S. W. & P. R. Jones. 1909. Additional observations on the lesser apple worm. U. S. D. A. Bureau o f Entom ology - Bulletin No. 80, Part III, pp. 45 - 50 Jaenike, J. 1990. Host specialization in phytophagous insects. Ann. Rev. Ecol. Syst. 21: 247 - 273 Papaj, D. R. & R. J. Prokopy. 1988. The effect o f prior adult experience on components o f habitat in the apple maggot fly (Rhagoletis pomonella). Oecologia 76: 538 543 Quaintance, A. L. 1908. The lesser apple worm. U. S. D. A. Bureau o f Entom ology Bulletin No 68, Part V. pp. 49 - 60 Renwick, J. A. A. 1989. Chemical ecology o f oviposition in phytophagous insects. 88 Experientia 45: 223 - 228 Renwick, J. A. A. & F. S. Chew. 1994. Oviposition behavior in Lepidoptera. Ann. Rev. Entomol. 39: 377 - 400 Sharma, H G. & D. M Norris. 1991. Comparative feeding preference and food intake and utilization by cabbage looper (Lepidoptera - Noctuidae) on three legume species. Environ. Entomol. 20: 1589 - 1594 Singer, M. C. 1986. The definition and measurement o f oviposition preference in plant feeding insects. In Insect - plant interactions, ed. T. A. Miller, J. A. M iller, pp. 65 - 94. New York: Springer - Verlag Sokal, R. R. & F. J. Rohlf. 1981. Biometry. 2nd ed. Freeman, New York Tabashnik, B E., H. W heelock, J. D. Rainbold, & W. B. Watt. 1981. Individual variation in oviposition preference in the butterfly, Co/ias eurytheme. O ecologia 50: 225 230 Taylor, E. P. 1909. Eggs and stages o f the lesser apple worm {Enannonia pnm ivora W alsh). J. Econ. Entomol. 2: 237 - 239 Thom pson, J. N. & O. Pellmyr. 1991. Evolution o f oviposition behavior and host preference in Lepidoptera. Ann. Rev. Entomol. 36: 65 - 89 W earing , C. H. & R. F. N. Hutchins. 1973. Alfa - farnesene, a naturally occurring oviposition stimulant for the codling moth Laspeyresiapomonella. J. Insect. Physiol. 19: 1251 - 1256 W ellhouse, W. H. 1920. W ild hawthorns as a host o f apple, pear and quince pests. J. Econ. Entomol. 13: 388 - 391 Yoshida, H. A. & M. P. Parrella. 1991. Chrysanthemum cultivar preference exhibited by Spodoptera exigua (Lepidoptera - Noctuidae). Environ. Entomol. 20: 160 165 CHAPTER 6 Larval and pupal characters for identification of lesser appleworm Grapholitaprunivora (Walsh), oriental fruit moth (7. molesta (Busck), and cherry fruitworm G. packardi Zeller (Lepidoptera : Tortricidae) Introduction Current trends in fruit protection against pests require that pesticides will be applied only when they are necessary. Integrated pest management practices or its single com ponents are primary components o f fruit protection methods in the majority o f North American orchards. The prim ary activities employed for achieving the goal o f lowering the use o f pesticides are. monitoring, utilization o f multiple m anagem ent tactics, action thresholds, and IPM education or use o f IPM communication systems (W halon & Croft 1984). M onitoring and sampling o f pest populations are two o f the most im portant elements in the process o f decision making in IPM. The correct estimation o f pest density, its economical threshold and phenological forecasts are elements on which the IPM decision making processes rely the most (Binns & Nyrop 1992). Use o f effective sampling procedures and the ability to correctly identify insects in the field are also important elem ents for effective pest control. Most commercially grown plants are under continuous attack from various 89 90 insect pests. M ost o f the potential plant enemies have already been described and identified. Some however, especially ones that occur sporadically, may cause a problem when for some reason they will appear in a plantation and start to cause im portant damage to the crop. Insects that can use a plant as a secondary, accidental or incidental host (Chapman 1973) are a good examples o f how such a situation can occur. Identification and separation o f insect life stages in many situations are the m ost crucial first steps in protection from damage. Identification and proper arrangem ent o f an organism into the right classification is a crucial first step during any research activity. Only when the object o f the research is properly identified can one try to find reasonable and effective ways o f dealing with a problem (Danks 1988). Examples o f the importance o f taxonomy and systematics in integrated pest m anagem ent programs in Southeast Asia are broadly discussed by Hardy (1982). The correct identification o f a pest by itself may be a solution to a problem, because the necessary information may be often found in the literature if one knows which species to search for. Although the identifications o f adult pest insects, is relatively accomplishable, especially for insects that are common in a given area, identification o f larval or pupal stages is often much m ore difficult. Detailed examination, often using powerful microscopes may be necessary for separating closely related species. W ith our current knowledge, the larvae o f three internal apple feeders: the lesser appleworm, Grapholita prunivora (W alsh), the cherry fruitworm, Grapholita packardi Z eller and the oriental fruit moth, Grapholita molesta (Busck) are very difficult to distinguish and can only be separated using characters such as size and coloration 91 retained after boiling them in hot water and preserving in 70 % ethanol (Chapman & Lienk 1971, Brown 1987). The num ber o f crochets on ventral and anal prolegs was also used to separated the two first species from the later one by M acKay (1959), but this is an ambiguous characteristic. The current study focused on identifying potential characters for identification o f larval and pupal stages o f these three species, and diagnoses o f fruit injuries caused by lesser appleworm, oriental fruit moth and cherry fruitworm larvae From the fruit growers point o f view, larval injury recognition may be o f the same importance, especially since fruit injuries are usually the first sign o f a pest presence in the system. Observations in the field , laboratory, and under light and scanning electron m icroscope were used in search o f dependable characters for correct pest diagnosis. Materials and Methods Insect colony. During the summers o f 1992 - 1994, apples were collected from abandoned orchards located in Douglas, Shelby, Kalamazoo, and Casnovia, MI. Larvae collected from apples were reared in growth cham ber at 16 : 8 h photoperiod, and tem perature 25: 16 °C respectively for developm ent o f insects. Emerged adults were collected and placed into 40.3 cm L x 27.7 cm W x 15.1 cm H plastic boxes (Sterilite Co. USA) with nine apples arranged in three groups o f three fruits. Approximately 10 males and 10 females w ere released in each box. M oths in each box were supplied w ith small plastic containers with water and a water and honey solution replaced every second day. During July, rearing boxes were kept outside under ambient conditions, w hile starting from August growth chambers were used for insect rearing. Twilight conditions were 92 provided by a one 75 W light bulb placed in the m iddle o f the growth cham ber turned on for two hours daily. Larvae collected from fruits w ere reared in Petri dishes, using pieces o f apple as food source. Each Petri dish had two filter paper disks placed inside for a pupation site. Every 3 to 4 days drops o f w ater were added to the filter paper for providing moisture. After eclosion adults were carefully transferred to a new box with fresh fruits. During fall and w inter I used apples collected during late sum m er (August, September) from pesticide - free orchards and they were placed in cold storage. Four apples varieties were used for maintaining moth colonies: “Red D elicious”, “ Em pire” , “Golden D elicious” , and “Granny Smith” . The last variety was used m ainly during winter, when no other apple variety could provide a food source. Pupae. Pupae o f lesser appleworm, oriental fruit moth and cherry fruitworm were collected from the sam e apple blocks as for starting colony. All pupae removed from fruits w ere placed in plastic vials with a loose stopper for air flow. Each pupa was examined under a light m icroscope (Carl Zeiss, Germany), using a 10 x graduated ocular eyepiece. Two hundreds units under microscope equaled 10 mm. Three diagnostic characters were measured on each individual: a) length o f pupa from anterior o f frontal ridges to posterior tip o f anal segment, b) width o f dorsal part o f m esow ing behind prothorax, and c) width o f dorsal part o f anal segment. These parts w ere chosen as the characteristic elements, being im portant in the optical image o f the pupae. Each pupa was categorized as to species and sex. Assignm ent o f each pupa into male or fem ale group was based on the num ber o f independently m ovable abdominal segments. M ale pupae have four, whereas fem ale pupae have three m ovable abdominal 93 segments (A dler 1991). Pupae w ere placed in vials until adult emergence when species and sex assignm ent were verified. After emergence, adults w ere used to augm ent the insect colony. Larvae. Larval measurements w ere made only on larvae collected out o f established moth colonies. After leaving the fruit and m oving between filter papers inside Petri dishes, last instar larvae were collected and preserved using KAAD or hot w ater and stored in 70 % ethanol. The num ber and structure o f prongs on the anal comb, the num ber o f crochets on last pair o f ventral prolegs, and the num ber o f crochets on anal prolegs were determined under 50 x magnification using light m icroscope (Carl Zeiss, Germany). Voucher specimens have been deposited in the Center for Insect D iversity Study in Departm ent o f Entom ology at M ichigan State University. Scanning electron m icroscopy. Pupae o f the three exam ined species w ere also observed on a JEOL scanning electron microscope (JSM - 6400V) at the M ichigan State U niversity Center for Electron Optics. Pupae collected from known moth colonies were fixed in glutaraldehyde with buffer, washed in phosphate buffer, and gradually dehydrated through a series o f 25%, 50 %, 75%, 95% and 100% ethanol using 30 minutes per step. Samples were then critical-point dried (Flegler et al. 1993). Samples were mounted on stubs, using double-sided tape, and graphite was painted on the edges o f stubs. All samples w ere sputter coated with gold. Samples were then exam ined at lOkV and 39 mm w orking distance at various magnifications. Fruit injury characteristics. In addition to pupal and larval characters an attempt to diagnose fruit injuries among the three species was conducted. Using sim ilar methods as for the lesser appleworm colony establishment, cherry fruitworm and oriental fruit 94 moth colonies were established on apple as a food source. Observations o f external and internal fruit injury pattern w ere made on fruits infested by larvae. For comparison o f larval and pupal characters, m ultivariate statistics were applied. Correlation coefficients among different characters within the species w ere applied for the analysis o f diagnosed forms (Daly 1985). Results and Discussion. Pupal characters. Lesser appleworm pupal characters were measured on n = 110 fem ale and n = 104 male pupae. Length o f male pupae averaged 5.07 ± 0.3 1 mm and ranged from 4.1 mm to 6.0 mm; in females it ranged from 4.1 mm to 5.55 mm with average o f 4.93 ± 0.3 mm. The width o f mesowing on dorsal side in both sexes ranged from 0.8 mm to 1.65 mm, with the width o f the anal segments ranging from 0.25 mm to 0.5 mm (Table 1). Oriental fruit moth characters were measured on n = 37 male and n = 18 female. Length ranged from 5.15 mm to 7.6 mm averaging 6.09 ± 0.32 mm for males and 6.6 ± 0.63 mm for females. Oriental fruit moth pupal mesowing width ranged from 1.2 mm to 2.0 mm averaging 1.64 ± 0.13 mm for males and 1.76 ± 0.19 mm for females, with the anal segm ent width ranged from 0.4 mm to 0.65 mm. M easurem ent o f n = 12 males and n = 10 females o f cherry fruitw orm pupae showed their length ranged from 4.3 mm to 5.35 mm, mesowing w idth ranged from 0.9 mm to 1.4 mm, and anal segments width ranged from 0.3 mm to 0.5 mm (Table 1). The size o f measured pupae is in general agreement with data presented by Adler (1991), who examined four unsexed individuals, and found that lesser appleworm pupae 95 T a b le 1. C om parison o f pupal length, m esow ing w idth, and anal segm ent w idth o f lesser applew orm (L A W ), oriental fruit m oth (OFM ), and cherry fruitw orm (CFW ). Species C haracter n Mean" sn Range" length 104 5.07 0.31 4.1 -6.0 m esow ing w idth 104 1.39 0.11 0.95 -1.6 anal segm . w idth 104 0.37 0.04 0 .2 5 -0 .5 length 110 4.93 0.3 4.1 - 5.55 m esow ing w idth 110 1.35 0.12 0 .8 - 1.65 anal segm . width 110 0.35 0.04 0.3 - 0.5 length 37 6.09 0.32 5.4 - 6.75 m esow ing w idth .17 1.64 0.13 1.2- 1.9 anal segm . w idth 37 0.51 0.06 0.4 - 0.65 length 18 6.6 0.63 5 .1 5 -7 .6 m esow ing w idth 18 1.76 0.19 1 .3 5 -2 anal segm . w idth 18 0.57 0.06 0.4 - 0.65 length 12 4.87 0.32 4.3 - 5.35 m esow ing w idth 12 1.2 0.12 1.05- 1.4 anal segm . width 12 0.38 0.05 0.3 -0.5 length 10 4.82 0.22 4.3 - 5.05 m esow ing w idth 10 1.14 0.12 0 .9 - 1.3 anal segm . w idth 10 0.34 0.04 0.3 -0.4 Sex m ale LA W female m ale O FM fem ale m ale C FW female ‘‘ - all data are in m m Mode" 4.95 1.45 0.35 4.95 1.3 0.35 6 1.7 0.4 6.9 1.6 0.6 4.85 1.3 0.35 5.05 1.2 0.3 96 are in length range o f 4.5 mm to 6.0 mm. Sim ilarly small differences between my data and Adler (1991) exist for measurements o f cherry fruitworm and oriental fruit moth. Adler (1991) used a color as an additional character for pupae diagnosis but I did not find color useful as a character for separating these three species. Color o f pupae can change based on the developm ent o f internal moth structures, and it is extremely difficult to use color descriptions (various shades o f brown) as a character for identification. Correlation coefficient “r ” for characters within species showed how difficult it is to separate pupae o f lesser appleworm and cherry fruitworm from pupae o f oriental fruit moth (Table 2). The highest r values were observed for oriental fruit moth pupal length and width o f mesowing (/' = 0.84). Other characters within species showed various values o f correlation coefficients. They ranged from r = 0.39 for cherry fruitworm length and anal segment width, to r = 0.69 also for cherry fruitworm pupae, but for correlation cofficient o f anal segment width and mesowing width. On the other hand using only visual observations o f the general shape o f pupae, and individual relations o f three characters: pupal length, mesowing width, anal segm ent width, and num ber o f movable abdominal segments, I classified correctly 91.5 percent o f pupae into species and sex (Table 3). This test showed that one can relatively well separate the pupae o f oriental fruit moth from those o f lesser appleworm and cherry fruitworm. M ore problems arise during separation o f the last two species. Some extrem e values o f pupal characters are responsible for the misidentification o f a few lesser appleworm and oriental fruit moth. Two dimensional plots o f pupal length and width o f m esow ing and anal segment show the differences that will allow one after getting some 97 T a b le 2. Correlations coefficien ts for three pupal characters; length, width o f m esow in g, and width o f anal segm ent for lesser appleworm (L A W ), oriental fruit moth (O FM ), and cherry fruitworm (CFW ). L A W ien. L A W m es. LA W anal LA W ien” 1 I, A W ines1’ 0.438835 1 L A W anal' 0.410816 0.364996 1 O FM len. O FM m es. OFM unul O FM len. 1 O FM m es. 0.839728 OFM unul 0.54371.3 0.477736 1 1 C FW len. C FW m es. CFW unul CFW len. 1 C FW m es. 0.626319 CFW unul 0.390674 0.696313 1 1 “ - length o f pupae from anterior o f frontal ridges to posterior tip o f anal segm ent h - width o f dorsal part o f m esow ing behind prothorax c - w idth o f dorsal part o f anal segm ent 98 Table 3. Accuracy of species identification using visual characters to categorize pupae of lesser appleworm (LAW), oriental fruit moth (OFM), and cherry fruitworm (CFW) Species Predicted " Observed Percent LAW OFM CFW correct LAW 213 201 3 9 94.37 OFM 60 8 52 0 86.7 CFW IX 5 0 13 72.2 214 55 22 91.4 Total " ’ number of expected pupae that belongs to a given species. Observation based only on general appearance of the pupa 99 experience to correctly identify pupae (Figure 1 and Figure 2) The oriental fruit moth pupae are generally bigger and w ider in appearance than lesser appleworm or cherry fruitworm Among examined oriental fruit moth specimens, 92.6 percent o f the pupae had a ratio o f pupal length to width o f mesowing between 3.28 and 3.98 (Figure 3).Cherry fruitworm pupae are the thinnest, most delicate in comparison with the other two species. Although there were low numbers o f cherry fruitworm pupae exam ined, the ratio o f pupal length and width o f mesowing for 95.2 percent o f pupae varied from 3 .9 to 4.54 (Figure 3). Understanding o f those subtle differences may be especially important for field identifications w ithout the possibility o f using m agnifying equipment. Additional hints for identification include differences in larval pupation behavior. Full grown larvae o f lesser appleworm leave the fruit to prepare a pupation site. They may use numerous available sites such as leaves, corrugated paper or scars on fruit tissue. Often, when they use dry leaves for making a cocoon, they form a characteristic “folded envelope” with flat bottom and convex top part (Figure 4). In the laboratory, when larvae were provided with corrugated paper, they formed a small cocoon on the side o f the tunnel using a top layer o f paper. The oriental fruit moth larva closes the whole tunnel and use it entirely for making a much larger cocoon, sim ilar to codling moth. There were no detailed observations o f cherry fruitworm pupation behavior during the experiment, due to a low numbers o f specimens Even using scanning electron microscopy as a tool, I was not able to find definitive pupal difference among the three studied species. My goal was to find differences under high m agnification, that can be observable even without using electron microscopy. Observing cherry fruitworm pupa’s dorsal side, two rows o f spines are 100 L esser appleworm pupal length and m esowing width mesowing width (mm) 2 .5 2 15 1 0 .5 3 3 .5 4 4 .5 5 5 .5 6 6 .5 7 7 .5 8 7 .5 8 7 .5 8 le n g th (m m ) mesowing width (mm) O rien ta l fru it m oth p up al length and m eso w in g w id th 2 .5 2 1.5 0 .5 3 35 4 4 .5 5 5 .5 6 6 .5 7 l e n g t h (m m ) mesowing width (mm) C h erry fru itw orm pupal length and m eso w in g w id th 2 .5 2 1 .5 1 0 .5 3 35 4 4 .5 5 5 .5 6 6 .5 7 l e n g t h (m m ) F igure 1. Comparison of pupal length and mesowing width of three internal fruit feeders : lesser appleworm, oriental fruit moth, and cherry fruitworm. 101 Lesser appleworm pupae width (mm) - m esow ing O a n al s e g m . i ! | ! j e n n g a fftiB S B S B S fita 3 3 .5 4 4.5 5 5.5 ° 6 j 6 .5 7 7.5 8 le n g th (m m ) Oriental fruit moth pupae • m esow ing 1 width (mm) O an at segm | o 3 3.5 4 4 .5 5 8 f i 0 '! 8 > < i» < S i® < ® 5.5 6 6.5 7 O O 7.5 8 le n g th (m m ) Cherry fruitworm pupae - m esow ing width (mm) O a n al s e g m 8 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 le n g th (m m ) F ig u r e 2. Com parison o f three pupal dim ensions: length, m esow ing width, and anal segm ent width o f lesser applew orm , oriental fruit m oth, and cherry fruitworm. 102 6.07 Lesser appleworm R atio Number of p u p a e Oriental fruit moth 3 .2 9 3 .4 6 3.64 3.81 3 .9 8 4 .1 5 4.33 R a tio Cherry fruitworm 3 .5 8 3.90 4.22 4.54 R atio F igure 3. Frequency of ratios between pupal length and width o f mesowing for lesser appleworm, oriental fruit moth, and cherry' fruitworm pupae 103 Figure 4. Lesser appleworm Grapholitaprunivora (Walsh) pupal cocoons a) on apple fruit, b) on leaf, c) on filter paper, and d) on hawthorn fruit. 104 visible on abdominal segments 2-7, and a single row on segments 8 - 9. On segments 4 -6 the anterior rows contain double rows o f overlapping small spines (Figure 5) The anterior row o f dorsal spines on the lesser appleworm and oriental fruit moth are composed o f single row o f spines. Lesser appleworm and oriental fruit moth pupae have the posterior row o f dorsal spines about 50 percent sm aller than anterior one and located at a distance two/third o f the width o f the segm ent toward the posterior end. Cherry fruitworm has its posterior rows o f spines relatively bigger when compared to previous species, but almost two/third o f size o f first row and located very close to posterior edge. A dler (1991) used the num ber o f anterior rows o f spines on abdominal segments 4 - 6 as a m ajor diagnostic character. She did not use the size o f spines and their position on the segm ent as a character for species identification. Larval characters. Larval identification o f lesser appleworm, oriental fruit moth, and cherry fruitworm has always been difficult. In identification keys am ong lesser appleworm and oriental fruit moth larvae the main characters are larval size, or color difference between those two species. Chapman & Lienk (1971) in their key for apple feeders in New York found that lesser appleworm larvae retain pinkish color when stored in 70 % alcohol, and that does not happen for oriental fruit moth or cherry fruitworm larvae. There is also an overlap in larval length and head width. A ccording to Chapm an & Lienk (1971) lesser appleworm larval head width is 0.77 - 0.85 mm and length is 7.5 9.5 mm, when for cherry fruitworm the head width is 0.85 - 0.94 mm, and length 7.5 9.0 mm. Brown (1987) in his key for tortricid larvae present on fruits use the color o f 105 a) b) c) Figure 5. Scanning electron microscope photographs o f dorsal abdominal part o f three tortricid pupae: a) Grapholitaprunivora (Walsh), b) Grapholita molesta (Busck), and c) Grapholita packardi Zeller 106 pinacula on posterior segm ent and body color in alcohol as main characters to distinguish between cherry fruitworm and lesser appleworm. To find other characters for identifying the lesser appleworm, cherry fruitworm and oriental fruit moth larvae, I measured the anal comb configuration and counted the num ber o f crochets on the prolegs. Crochets are small hooks arranged in row or circles around the edge o f the planta (Brown 1987). All three species showed differences in the num ber o f crochets on the last pair o f ventral prolegs and on the anal prolegs (term inology as in Brown 1987), Crochets on the ventral prolegs are arranged in an uniordinal circle or oval, and crochets on anal prolegs are arranged in uniordinal half oval row. Lesser appleworm larvae (n = 40) had an average o f 14.91 crochets on the anal prolegs (Table 4); cherry fruitworm (n = 7) had 17.8, and oriental fruit moth (n = 29) had 23 .77 crochets. On the last pair o f ventral prolegs they had respectively : lesser appleworm - 24.33, (n = 39); cherry fruitworm - 26.21, (n = 7); and oriental fruit moth 35.46 (n = 27) (Table 4). Except for cherry fruitworm right and left anal prolegs, the num ber o f crochets on each proleg and pair o f prolegs shows positive correlation (Table 5). The number o f crochets on ventral prolegs in lesser appleworm larvae (range 21 - 30) is different from that in oriental fruit moth (range 2 6 -4 1 ) , with one exception, when on oriental fruit moth larva had only 26 crochets on its last ventral right proleg (Figure 6). This character can be used as a good character for larval identification. In the case o f the cherry fruitworm the num ber o f crochets on prolegs were included in the range o f those o f the lesser appleworm which makes it impossible to use this character for identification o f those tw o species. A scatter plot o f number o f crochets am ong three species shows 107 T able 4. Comparison table of number of crochets on last pair of ventral prolegs and on anal prolegs on lesser appleworm (LAW), oriental fruit moth (OFM), and cherry fruitworm (CFW) Species n Left Right x (L + R) SD Range a N u m b er o f cro ch ets on anal p air o f p ro leg s Mode L -R LAW 40 14.98 14.85 14.91 2.05 1 0 -1 9 13 - 15 OFM 29 23.14 24.39 23.77 2.8 1 7 -2 9 23 - 23 CFW 7 17.43 18.17 17.8 1.54 1 5 -2 0 17 - 18 N u m b er o f cro ch ets on last p air o f v en tra l p ro leg s LAW 39 24.31 24.36 24.33 2.17 2 1 -3 0 22 -24 OFM 27 35.26 35.67 35.46 3.17 26 -4 1 38 - 35 CFW 7 26.14 26.28 26.21 2.55 23 - 30 28 - 26 a - ran g e from left and right prolegs 108 T able 5. Correlation coefficients for number of crochets on last pair of ventral prolegs and on anal prolegs for larvae o f lesser appleworm (LAW), oriental fruit moth (OFM),and cherry fruitworm (CFW). Lesser applewomi Correlation coefficients ana1L. anal 11. anal L." 1 anal R.” 0.717985 ventral L. ventral 11 1 ventral L. 0.455088 0.457138 1 ventral R. 0.421467 0.477823 0.677166 1 Oriental fruit moth ana! 11. anal L. anal L. 1 anal R. 0.82079 ventral L. ventral 11. 1 ventral L. 0.472525 0.673335 1 ventral R. 0.370251 0.563121 0.633814 1 Cherry' fruitworm anal L. ana! 11. anal L. 1 anal R. -0.10775 ventral L. vevtral 11. 1 ventral L. 0.419965 0.566352 ventral R. 1 0.26367 0.824465 0.895044 " - crochets on left proleg h - crochets on right proleg 1 109 L esser applcw orm - num ber o f crochets on ventral prolcgs 45 R ig h t 35 25 15 5 5 10 15 20 25 30 35 40 45 40 45 40 45 L eft O r ien ta l fru it m oth - n u m b er o f c r o ch ets on v en tra l prolcRS 45 Right 35 25 15 5 5 10 15 20 25 30 35 L e ft Cherry fruitw orm - num ber of crochet on ventral prolcgs Right 35 25 0 O ° 8 15 5 ------------------ 1-------------------1-------------------1------------------ <-------------------1-------------------1--------------5 10 15 20 25 30 35 L eft F ig u re 6. Comparison o f num ber o f crochets on last pair o f ventral prolegs in lesser appleworm (LAW ), oriental fruit moth (OFM), and cherry fruitworm (CFW ) 110 pattern that may be useful for species separation, but overlapping numbers decrease the value o f this character (Figure 7). M acKay (1959) in her attempt to separate those species, used the number o f crochets and ratio o f spinneret length and width as an useful way for separation o f oriental fruit moth larvae from larvae o f lesser appleworm and cherry fruitworm, but she also found it impossible to separate the later two species based on crochet difference. Anal com b. All three species have a moderately developed an anal comb. The anal comb is defined as a mesal sclerotized prong ventrad o f the anal plate and adjacent to the anus (Stehr 1987). The function o f the anal comb is not well defined. Frost (1919) compared the advantages and disadvantages o f presence o f anal comb for external and internal plant feeders, but no definite conclusions were found. Stehr (1987) define anal comb function as “used to eject frass” (pp. 711). Prongs are straight, o f various lengths. Individuals o f lesser appleworm larvae have the number o f prongs from 4 to 9, oriental fruit moth from 4 to 7, and cherry fruitworm from 4 to 6. All analyzed specimens show a large difference in the prong arrangem ent (Table 6). On some studied specimens only prongs o f the sam e size were observed, but the majority o f larvae had various prongs arrangements. There were no detectable differences among species that can be use for larvae identification. Fruit injury. All three examined species, along with the codling moth are grouped by orchardists as internal fruit feeders. All o f them feed inside the fruit, but the dam age they cause is different. Lesser appleworm larvae enter the fruit at any point, but usually at the calyx or stem end. Larvae usually borrow through the skin and feed exclusively under the skin. In contrast to the oriental fruit moth or codling moth it does not tunnel to Ill Lesser appleworm - num ber o f crochets on anal prolcgs 30 25 ■C at £ 20 15 o o 10 —4“ 5 10 -1 20 15 25 30 L e ft Oriental fruit moth - num ber of crochets on anal prolcgs 30 25 _o> 20 b£ 15 10 5 10 20 15 25 L e ft Cherry fruitworm - number of crochets on anal prolcgs L eft F igure 7. Comparison o f number of crochets on anal pair of prolegs in lesser appleworm (LAW),oriental fruit moth (OFM), and cherry fruitworm (CFW). 30 112 T ab le 6. Configuration o f prongs in anal comb in lesser appleworm (LAW), oriental fruit moth (OFM ), and cherry fruitworm (CFW ) LAW OFM I 5 7 4 2 3 4 3 7 3 4 / 4 7 4 7 5 7 4 6 7 4 7 5 7 7 17 1 72 7 2 / 1 2 2 / 4 7 4 / / 5 7 4 4 7 4 / 4 / 3 3 I 7 1 / 2 / 5 / 7 4 7 4 2 5 7 4 7 5 4 7 7 4 2 4 4 7 3 /' 7 3 7 7 4 7 7 3 7 7 5 7 4 / (. 7 2 2 2 4 4 5 4 2 5 4 3 4 4 4 4 7 7 5 6 4 5 4 4 4 6 4 2 7 5 5 4 2 1 5 CFW / 7 1 I 2 2 3 7 7 7 7 2 J 2 1 - numbers in italics show num ber o f weak prongs 1 - num bers in bold show num ber o f strong prongs 5 3 2 5 4 7 2 1 J 4 113 the apple seeds, although it may go deeper into the fruit. W hen lesser appleworm larvae tunnel into the fruit, the core line was the limit, inside o f which we never saw any damage. I did not find lesser appleworm larvae feeding on seeds. Externally on fruit, a small amount o f frass is visible only at the entrance point. Most o f the frass remains within the tunnels under the skin. Tunnels made by lesser appleworm larvae are a snake shaped. One end o f the tunnel, where the larva is present, is much wider. Lesser appleworm larvae are usually visible through the skin. Oriental fruit moth and especially fresh codling moth injury may also sometimes looks similar, however older larvae are usually tunneling inside the fruit and feeding on seeds in core area. Fruit injury characteristics o f the lesser appleworm are shown on Figure 8. Lesser appleworm larvae were never observed feeding on any other part o f the tree than the fruit. It was never found feeding on leaves or young growing watersprouts. Quaintance (1908) reported this leaf feeding o f larvae, but it was not found during our observations. Chapman & Lienk (1971) observed that fruit injured by the first generation o f lesser appleworm drop from tree to the ground. I was unsuccessful in collecting larvae from dropped fruit, probably since the injury did not affected fruit seeds, and did not force the fruit to drop. Conclusions. No one single character will allow for definitive identification o f lesser appleworm, cherry fruitworm, and oriental fruit moth larvae and pupae. The identification o f oriental fruit moth pupae due to its relatively bigger size and appearance, and to characters that overlap only on the edges with characters o f the two other species is relatively accomplishable. Lesser appleworm can be identified only after careful examination o f all pupal and larval characters and preferably by the kind o f injury 114 Figure 8. Apple fruits injured by leser appleworm Grapholita prunivora (Walsh)larvae 115 it caused on the fruit. For separating cherry fruitworm larvae or pupae from those o f lesser appleworm, only detailed examination with special attention given to a relation among diagnostic characters and general, optical shape can be used. Although strong overlap in the examined characters exist between these two species, it is possible after getting some experience, to accomplish this task. The best results can be accomplished when we are able to deal with all three species at the same tim e and comparisons can be done. R eferences C ited: Adler, C. R. L. 1991. Identification o f pupae on apple in Eastern North America, in: Tortricid pests, their biology, natural enemies and control, ed. by. L. P. S. van der Geest & H. H. Evenhuis, Elsevier, Holland, pp: 51 - 64. Binns, M. R. & J. P. Nyrop. 1992. sampling insect populations for the purpose o f 1PM decision making. Ann. Rev. Entomol. 37: 427 - 453 Brown, R. L. 1987. Tortricidae. in: Immature insect ed. by F. W. Stehr. Kendall / Hunt Publishing Company. Dubuque, Iowa, pp: 419 - 433 Chapman, P. J. 1973. Bionomics o f the apple - feeding Tortricidae. Ann. Rev. Entomol. 28: 7 3 -9 6 Chapman, P. J. & S. E. Lienk. 1971. Tortricid fauna o f apple in New York (Lepidoptera: Tortricidae); including an account of apples’ occurrence in the State, especially as a naturalized plant. New York State Agricultural Experimental Station, Geneva, Special Publication, 122p. Daly, H. V. 1985. Insect morphom etries. Ann. Rev. Entomol. 30: 415 - 438 Danks, H. V. 1988. Systematics in support o f entomology. Ann. Rev. Entomol. 33: 271 - 296 Flegler, S. L., J. W. Heckman, & K. L. Klomparens. 1993. Scanning and transm ission electron microscopy; an introduction. W. H. Freeman & Co. New York, pp. 225 116 Frost, S W 1919. The function o f the anal comb o f certain lepidopterous larvae. J. Econ. Entomol. 12: 446 - 447 Hardy, D. E. 1982. The role o f taxonomy and systematics in Integrated Pest M anagem ent programs. Protection Ecology 4: 231 - 238 MacKay, M. R. 1959. Larvae o f the North American Olethreutidae (Lepidoptera). Can. Entomol. 91 (Suppl. 10). 338p. Quaintance, A. L. 1908. The lesser apple worm. U. S. Department o f Agriculture, Bureau of Entomology. Bulletin No. 68, Part V. Washington 1908. Stehr, F. W. 1987. Immature insects. Kendall / Hunt Publishing Company, Dubuque, Iowa, 754 p. W halon, M. E. & B. A. Croft. 1984. Apple IPM implementation in North America. Ann. Rev. Entomol. 29: 435 - 470 APPENDIX APPENDIX 1 Record of Deposition of Voucher Specimens* The s p e c im e n s l i s t e d on th e f o l l o w i n g s h e e t ( s ) h a v e b e e n d e p o s i t e d in t h e named museum(s) a s s a m p le s o f t h o s e s p e c i e s o r o t h e r t a x a w h ic h w ere used in t h i s r e s e a r c h . V ou ch er r e c o g n i t i o n l a b e l s b e a r i n g t h e Voucher No. h a v e b e e n a t t a c h e d o r i n c l u d e d i n f l u i d - p r e s e r v e d s p e c i m e n s . V ou ch er N o .: ________ 1996 - 2____________________ T itle of th e sis or d isse r ta tio n (or o th e r resea rch p r o j e c t s ) : BIOLOGY AND PEST STATUS OF LESSER APPLEWORM GRAPHOLITA PRUNIVORA (WALSH) (LEPIDOPTERA - TORTRICIDAE) IN MICHIGAN Museum(s) w h ere d e p o s i t e d and a b b r e v i a t i o n s f o r t a b l e on f o l l o w i n g s h e e t s : E n tom ology Museum, M ic h ig a n S t a t e U n i v e r s i t y (MSU) O th e r Museums: I n v e s t i g a t o r ' s Name ( s ) (typ ed ) Grzegorz Krawczyk_______________ D ate A p r il 0 4 .1 9 9 6 *R eference: Y o s h im o to , C. M. 1 9 7 8 . V oucher S p e c im e n s f o r E n tom ology i n N orth A m e r ic a . B u l l . E n to m o l. S o c . Amer. 2 4 : 1 4 1 - 4 2 . D ep o sit as fo llo w s : O rig in a l: C o p ie s : I n c l u d e a s A p p e n d ix 1 i n r ib b o n c o p y o f t h e s i s o r d isse r ta tio n . I n c l u d e d a s A p p e n d ix 1 i n c o p i e s o f t h e s i s o r d i s s e r t a t i o n . Museum(s) f i l e s . R esearch p r o j e c t f i l e s . T h is form i s a v a i l a b l e from and t h e V oucher N o. i s M ic h ig a n S t a t e U n i v e r s i t y E ntom ology Museum. 11 7 a s s i g n e d by t h e C u r a t o r , Museum where depos­ ite d O th e r Adults Pupae ? Grapholita prunivora (Walsh) Label data for specimens collected or used and deposited 1 Michigan, Allegan Co. Douglas 130 S tr. T3N,R16W, sec. 21 Col. Sept. 1994, from moth colony Nymphs Species or other taxon ■ ■■■ L arvae i " ■■■——.. ■ ■■Number o f: m > a to e Tw O rr (O ----- 8 1) 2 12 ( 2) 19 ( 3) MSU --- --- --- MSU Cydia pomonella (Linnaeus) Michigan, Allegan Co. Douglas 130 S tr. T3N.R16W, sec. 21 Col. Sept. 1994, from moth colony 20 MSU 1 (typed) Grzeaorz Krawczvk_________ Voucher No. 1996 - 2 Received the above lis te d specimens for deposit in the Michigan State University /IjUi 1 H Date April 04. 1996 Date Jawec? fSa bti S. MiltG&iW T Pages In v estig a to r's Name(s) of (Use additional sheets i f necessary) D a ta 7 Specimen Michigan, Allegan Co. Douglas 130 S tr. T3N.R16W, sec. 21 Col. Sept. 1994, from moth colony 1 Grapholita packardi Z eller Voucher MSU Michigan, Allegan Co. Douglas 130 S tr. T3N.R16W, sec. 21 Col. Sept. 1994, from moth colony Page 25 ( 1) 2 35 ( 2) 13 25 (3) Grapholita molesta (Busck)