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J» ll“; ‘Lékv"~’- LIBRARY ”2 Michigan Stat: University CHEMICAL CONTROL STUDIES WITH CORRELATIVE BIOLOGICAL FACTORS PERTAIHING mO THE APPLE APHID, APHIS POTI DEGEER, IN SOUTHIJSTERN KICHIGAN by JORDAN BRADLEY TATTE; AN ABSTRACT Submitted to the College of Science and Arts Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of EntomolOEY 1960 .-/ ”I... \r i / Approved. j/\\ {i 9/ [/i L L 33,4‘ L k This research project considered three objectives: (1) To correlate biological factors of the apple awhid, Aphis pomi DeGeer, with: (2) The evaluation of several recently develOped compounds suSpected of insecticidal prOperties for the control of the apple aphid eXposed to field conditions in Southwestern Michigan, and; (3) The development of a simplified method of collecting performance data on the control of A, 2931' Populations of the apple aphid were observed to increase in prOportion to host vigor. A definite preference by the apple aphid to activolv growing tissue was noted. Continuous migration by aphids to newly-formed plant tissue occurred during the growing season. Infestations required control measures by mid-July and peak pepulations were recorded in mid-August. A group of 28 materials were evaluated for control of the apple aphid on Twenty Ounce Pippin variety of apples. Outstanding materials were Dimethoate, PhOSphamidon, Systox, Compounds thZ and S727; Systemic-type chemicals were superior to the surface-residual compounds in effectiveness for aphid control. A simplified method for sampling parameter pepulations of apple aphids was devised. The system.denoted as "count rate" was based on migration and feeding habits of the aphids. ("1 Statistical procedures for proof of significance were ii applicable to count—rate data. The technique was rapid, accurate and practical for usage by commercial apple growers. F. Ho Ho CHEIICAL CONTROL STUDIES fiTTH CORRELATIVE BIOLOGICAL FACTORS PERTAIHIRG TO THE APPLE APHID, APHIS POMI DEGEER, IN SOUTHWESTERN NICHIGAN by JORDAN BRADLEY TATTER A THESIS Submitted to the college of Science and Arts Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of Department of Entomology 1960 (3“ /‘s? Z'ji‘éé e \S) drown—v ~ .» JJ“LI I~ .LD‘ArJIA.’_JaL\C.Lb I wish to extend my appreciation to Professor Ray Hutson, who, as chairman of the Department of Entmnology, aided in making this project possible. To Dr. Robert G. Haines, Department of Entomology, who freely gave his guidance and constant encourage ent leading to the successful completion of this research goes my sincere thanks. My grateful acknowledgment is extended also to Drs. E.C. Martin, Department of Entomology, and Edward J. 1103, Department of Botany and Plant Pathology, who as members U) of the writer' a‘visory committee, were most helpful. In addition, the author wishes to express his siecere gratitude to those others who have contributed their assistance, and eSpecially to my wife, Hary, for her patience, unde'standing and diligent efforts in tLe pre- paration of the final manuscript. TABLE OF COITERTS INTRODUCTION . . . . . . . . . . OBJECTIVES . . . . . . . . . . . LITERATURE REVIEN. . . . . . . . MATERIALS USE . . . . . . . . . EXPERIMENTAL PROCEDURES. . . . . EXPERIMENTAL RESULTS . . . . . . DISCUSSION . . . . . . . . . . . SIR-"MARY AND CONCLUSI OI.T S . . . . . LITERATURE CITED . . . . . . . . 93 "I (7.) “DJH _—- I TABLE I. II. III. IV. LIST OF TABLES Materials, Formulations, Quantities and Code Numbers for Experiment I.......... Materials, Formulations, Quantities and Code Numbers for Experiment II......... Temperature and Precipitation Data, July 19-September 1h, 1959, Benton Harbor Station, MiChiganooooo000.00.000.00. Mean Number of Leaf Pairs with more Live than Dead Apple Aphids as Determined for the Various Treatments Of Experiment 10000000000000.0000...0.00000 Mean NUmber of Leaf Pairs with more Live than Dead Apple Aphids as Determined for the Various Treatments Of Experiment IIOOOOOOOOOOOOOOOO0000.00.00. vii Page 17 27 Figure Page 1. Plot design for Experiment I............... 18 2. Plot design for Experiment II.............. 20 3. Experiment I; per cent reduction from controls for those materials with initial effectiveness above 80 per cent.... 28 h. Experiment I; mean number of leaf pairs with more live than dead apple aphids for those materials with initial effect- iveness above 80 per Cent...o.oo..........o 2 5. Experiment II; per cent reduction from controls for those materials with initial effectiveness above 80 per cent.... 30 6. Experiment II; mean number of leaf pairs with more live than dead apple aphids for those materials with initial effect- iveness above 80 per cent.................. 31 viii I ‘ ITRO DUCTT 01x" ' .2. Three species of aphids c mmonly infesting the apple (Pyrus malus Linnaeus) in Southwestern Michigan are: the apple aphid, Aphis ppmi DeGeer, the rosy apple achid, Anuraphis roseus Baker, and the apple grain aphid, Rhopalosiphum fitchii (Sanderson). On occasions rosy apple aphid pOpulations have caused greater injury to an apple crop than the other aphid groups, but control measures are much less involved. Although apple grain aphids may appear in alarming numbers soon after bud burst, this species normally migrates from the apple to grain crops within three weeks after hatching, and is of no further consequence to the grower. Since the apple aphid usually remains on the apple host during the entire growing season, it presents a continuous control problem for orchardists. Population densities are influenced mainly by environmental conditions and reinfestation by migration from uncontrolled areas is a common occurrence. One of the significant contributing factors to the increase in importance of the apple aphid has been the recent introduction of versatile chemicals for the control of orchard insects. Many predators and parasites have been destroyedin conjunction with varying prOportions of their hosts, but because of the biotic potential of the apple aphid, Specific controls have become necessary. Prior to each growing season, several new conpounds are provided by agricultural chemical industries for research personnel to evaluate. As part of this project, certain of these products were appraised in the field for _‘ ‘ aphicidal properties in anticipation of providing additional control measures for apple aphid infestations. A fundamental knowledge of the life history and appearance of the test species is basic to any biological research program. Information on the biology of the agile aphid was obtained in this study in correlation with control measures. The apple aphid was chosen for two reasons: because of the economic importance, and secondly, this insect was present in sufficient populations to permit a significant evaluation of chemical controls. ,W") T ‘Ifi‘fiI\fT?f‘ \li _}C J 'J ‘ 145) The major objectives of this research were: (1) To correlate the biological factors of the apple aphid, Aphis pom: DeGeer, with, (2) The evaluation of several compounds suspected of insecticidal prOperties for the control of the apple aphid exposed to local field conditions, and, (3) The develOpment of a simplified method of col- lecting performance data on apple aphid control. IJTKZHATTCII 35111:? Synonymy. The specific determination of the apple aphid as Aphis pomi was credited to Charles DeGeer in 1773: according to Baker and Turner (1916). However, the species was redescribed in 1775 by Johann Christian Fabricius as Aphis mali as indicated by Baker and Turner (1916) and subsequently noted by Matheson (1919). Investifiatiens by Parrott, Hodgkiss and Lathrop (1916) and by Fatheson (1919) suppert the initial description of Aphis pomi DeGeer empha- sizing that this specific name sh uld be applied to the ‘ - 9 A apple aphid. Personal correspondence with Miss Louise ;. Russell of the United States Depart ent of Agriculture, Agricultural Research Service, Entomology Research Division, 3 Specialist in aphid identification, has verified this fcct. prigin and Distribution. The apple aphid is of European origin. First appearance in Forth America according to Matheson (1919) was recorded to be prior to 185M. This author 0 f‘ based his opinion from an article by Fitch (1056) describing 'Hr the life cycle of the apple aphid as observed in new York plantings. However, Fitch errinfily applied the nawe Aphis avenae Fabricius, adding to the confusion on nomenclature. Hetcalf, Flint and Hetcalf (1951) stated tha the apple aehid H. s distributed generally throughout the apple producing 7 sections of North America. Tie first serious commercial infestations were reported by Hodgkiss (1919) to have occurred in New York State as early as 1C97. 2+ ,— J Plant Hosts. Katheson (1919) list plant species as'possible hosts of the ap~le aphid: apple, Pyrus malus Linnaeus; pear, Pyrus communis Iinneeus; wild crab, Pyrus coronaria Linnaeus; hawthorn, Crataegus oxyacaneha Linnaeus; Mountain ash, Pyrus americana Marsh; and species of Cydonia and Crataegus. The author also observed the following varieties of apples as most susceptible to apple phid injury: Twenty Ounce Pippin, Maiden Blush, King, Fall Pippin, Greening and Baldwin. An extensive listing of host plants of the apple aphid was complied by Patch (1923). Type f njury. Peairs (1950) stated that g. pomi “fl- .1 injury to apple fruits was limited primarily to the perioa innediately following bloom. Injury to foliage was also an important factor at that tine. Daring mid—summer apple aphids were more likely to be found on young trees and infesting new shoots than on mature apples or hardened vegetation. Early season injury by apple aphids was described by Natheson (1919) as a partial folding of the leaves. Parrott, $3.51: (1916) discussed the tendency of the stem-mothers to ascend the grosing shoots, feeding continuously on tender leaves. Hodgkiss (1919) reported that in New York orchards the apple aphid was considered more important as a dwarfing and defend- ation agent on the growth of younger trees than as a ‘ajor pest of mature apple trees. An interestin: ohserration made by Parrott, t al. (1916) was that during the latter part of summer the terminal 4. portions of new gro th ap_eared less able to withstand the feeding of apple aphids tha an earlier in the season. threme cases of infestation resulted in curled foliage, blackened by sooty fungus, with associated leaf drop and possible death 0; the terminal portion of the shoots. Life History and Seaso nal Activity. Smith (19CO) was one of the first to present a concise account of the life cycle and habits of the apple aphid 1n Ameri ca 5&1 wemrn he referred 1 stakenly to the insect as Aphis mali loch. Baker and Turner (1916) presented a factual account of the structural features and biology of Jhe apple aphid, and a summary of this work is reproduced herein from Hottes and Prison (1931). "The life his -tory of Aphis pemi may be briefly outlined as 1ollows; The e,g Is laid upon tender twigs of the apple, though occasionally it is laid upon the bark of the older twigs. It is light yellow when laid, but later changes to shining black. Development for a few days is very rapid, after which the egg res s for the winter. Uhen revolution of the embryo is completed in the sprinrg, an increase in temperature will cause t.e egg to hatch. Before this revolution a high tenperature only tends to destroy it. Early in April the egq hatches by a uniform splitting over the insect's head. The stem mother is winjless and beeches mature in about 10 days. She produces live summer forms, both winged and wingless, with the winced ones predominatino There are 9 to 17 generations of the mmer forms at Vienna, Va. After the second generation the winfiless forms alwavs outnumber the others, but winged ferns m y occur in every g ner— ation. They become rare toward the end of the season. On the other hand, a wingless line may be carried from the stem nether to the emf. A third form, the intermediate, may occur throughout the summer. The winfiless sexes be in to a~pear about th lst of September. They occur in all generations, from the eleventh to the nineteenth, inclusive, and ‘j\ probably also in the ninth and tenth. The summer win”1ess fir S and the oviparous fewales, w':ich live longer than the Pf.1es, remain on the trees at Vienna, Va. unti the leaves drop, usually about the middle of November. gating cow wences toward the close of dewtember, one t1ale usually servin“ more than one female. Beth seyes leed. The oviparous female may lay infertile efgs if not reached by a rale, and these e3;3s do not becwme black. Tie i ertile egg develOps to the resting stage before the first heavy frosts; otherwise it may be winterkilled and will not hatch to a ste= mother the following Spring.” Further examinations were “ade by Parrott et a1. (1916), Hodgkiss (1919) and Katheson (1919). Information derived from these studies closely o rallcled t‘1atof Taker and Turner (1916). Brittain (1915) made the re arkeble observation that on several varieties of apples A. pomi eggs hatch at the time the buds break. This phenomenon may vary despite identical environmental confiitions for different varieties according to Natheson (1919). He also stated that the apple aphid was the major aphid pest of apples, because it was the only species that rema.ined on the host throughout the growing season. Other species co monly migrate to alternate plant hosts soon after bloom. Natural Control. St ein ner (19let) noted that the toxicity of DDT to certain para 811x23 and predators had ca11sed SUl ficient reduction of the natural enemies of apple T), a pn ids to allow increases in aphid pOpul tions Betcslf, O: et a1. (1951) listed lady beetles, syrphid flies and ar‘1i I.) 10 U1 1 as common predators of t is apple awhid. The la2te authors stated that control problems became ‘. J C "C5 complicated durinc cool, damp seasons, s-nce A. omi increases more rapidly than its enemies when exnosed to these conditions. Host Resistance Factors. Varietal specificity and hes —1- J resistance was first observed by Gilchrist, an associate of I-’ Fitch, and reported by Titch (1895) earl '1 .4 r n the recorded F0 studies of the ape e aphid in North m.erica. latheson (1919) discovered variances in A. pomi nepulztions on different varieties of apples in the same orchards and attributed this to a resistance factor. Cultural Control. Certain cultural methrds of control were preposed by Hodgkiss (1919). These included wide Spacing of trees, removal of succulent water-sprouts during the growing season and the use of sod in orchards to aid in reducing the amount of tender tissue available for feeding. Chemical Control. Peterson (1919) conducted one of the first extensive studies of chemical control of the apple aphid. Among the materials investigated were fish oil soap, laundry soap, lime-sulfur, various petroleum oils, and nicotine sulfate. Prep this basic research nicotine sulfate in combination with lime-sulfur became the standard control measure. Since the advent of synthetic organic insecticides during the early 19h9's the wrevious standard compounds 10? control of A. pomi.have become obsolete. Dormant sprays were not SLfficient to prevent m11.:er popul: ti on increases of apple a.hiCs according to Cutrigh; (195 ). Le evaltated several chemica 3 during the prowin that cert aain o ;;a-ni c insecticides were the m st e1 ficient for aohid control. glass and Cnapna (1955) reported that parathion, malathion and Diazinon were toxic initially to the apple aphid, but lacked extended residual activity. This work also emphasized the effect of systemic insecti- cides as illustrated by Deneton (Systox) and leta-S"stox which were effective for three weeks in preventing rein- festation. 1eceLt investigations by German (19 S9 ) who evaluated J H combinations of insecticides and fungicides for control of insects ando diseases, showed the complex nature of present day pest control. He concluded that control, fruit quality, cost and safety of the materials are important factors in profitable orchard practices. Hadsen and Bailey (1959) screened a group of new com- pounds involving an original technique of evaluation. They determined the actual number of living aphi's on the third leaf from the terminal tip of an infested new sheet. Comparisons of mean values were made statistically for the various treatments but significant differences were not determined. The author wishes to express his appreciation 01 the organizations that contriouted t1e che ‘;icals used in this study. 1. Diazinon (C,O-diethyl O-(2-iSOpr0pyl-h-methyl-6- pyrimidyl) phosphorothioate). 25 per cent wettable powder; Geigy Chemical Corporation. Dibrom (0,0-dimethy1 O-(2,2-dibromo-l,2-dibromoethyl) phosphate) 8 pounds per gallon emulsifiable concentrate; California Spray-Chemical Corporation. Dimethoate (0,0-diemethy1 S-methylcarbamoylmethyl) phosphorodithioate). ‘1 pounds per gallon soluble concent°ate; American Cyanamid Cor Mp .ny. Endrin (1,2,3,h,lO,10-hcxachloro-6,7—epoxy-1,h,ha, ,7, ,8a-octahydro-l,h,5,8-endo-endo dimethanonaphthalene). 75 per cent wettable powder; Corona Chemical Division, Pittsburgh Plate Glass Coupany. L Vthion (0,0,C',)'-tetraethy1 S,S'-mcthy1ene diphos- phorodithioate). per cent wettable powder; Niagra Chemical Division, pood Machinery and Chemical Corporation. L jI‘J Ethyl Guthion (O, O-diethyl S-(h-oxo-BH,1, 2, 3-benzotriazine- 3-methy1) phosphorodithioate). 2 pounds per gallon emulsifiable conceitra te; Chemagro Corporation. Guthion (O, O-dimethyl S-(h-oxo-3H-1,2,3 -benzotriazine- 3- -methyl) phosp horodithioate). 1.5 pounds per gallon emulsi11able concentrate; Chenagro Corporation. Korlan (O, O-dimethyl O- (2,h,S-trichlorophenyl) phosphorothioate). 2 pounds per *allcn e .nulsifiable concentrate; The Dow Chemical Company. halathion (O, O- -dimethyl S- (1,2rbis-c rboethoxyethyl) phosphorodithioate). 25 per cent wettable powder; General Chemical Division, Allied Chemical Corporation. 10 10. ll. 12. 13. 1h. 17. 18. 20. ll Kcthyl Trithion (0,0-dimethyl(p-chlorophenylthio) methyl phosphorodithioate). 25 per cent wettable powder; Stauffer Chemical Company. Parathion (0,0-diethyl O-p-nitrOphenyl phosphorothioate). 8 pounds per gallon emulsifiable concentrate; California Spray-Chemical Corporation. Phosdrin (0,0-dimethyl O-l-methoxycarbonyl-l-prOpene- 2-yl phOSphate). 2 pounds per gallon emulsifiable concentrate; Shell Chemical Corporation. Phosphamidon (0,0-dimethy1 O-(2-chloro-2-diethyl- carbamoyl-l-prOpene-Z-yl) phosphate). h pounds oer gallon emulsifiable concentrate; California Spray-Chemical Corporation. Phostex (mixture of bis(dialkyloxyphosphinothioyl) disulphides). 8 pounds per gallon emulsifiable concentrate; Niagra Chemical Division, Food Uachincry Corporation. Ryania (Ryania speciosa). 100 per cent wettaEIe powder; 3.3. Pennick and Company. Sevin (l-naphthyl-N-methy carbamate). 50 per cent wettable powder; Union Carbide Chemicals Company, and h pounds per gallon enulsifiable concentrate; Stauffer Chemical Company. Systox (0,0-diethyl O-(and S)-ethyl-2-thioethy1 phosphorothioates). 2 pounds per gallon emulsifiable concentrate; Chemagro Corporation. Thiodan (6,7,8,9,10,10-hexachloro-l,5,5a,6,9,9a- hexahydro-é,9-methano-2,h,3-benzodioxathiepin- 3-OXide ) o 50 per cent wettable powder and 2 pounds per gallon emulsifiable concentrate; Niagra Chemical Division, Food Machinery Corporation. Trithion (S(p—chlorophenylthio) methyl O,)-diethyl phosphorodithioate). 25 per cent wettable powder; Stauffer Chemical Company. Compound hh02 (1,3,h,5,6,7,8—octachloro-3a,h,7,7a tetrahydro-h,7-methanophthalan). 1.25 pounds per gallon emulsifiable concentrate; Shell Development Company. 22. N ON. 0 27. Compound 5539 (Not released). 2 pounds per gallon emulsifiable concentrate; Shell LevelOpncnt Company. Compound 5727 (Not released). 1.25 pounds per gallon enulsifiable concentrate; Hercules Powder Company. Compound 22h08 (Bayer) (naphthaloximide C,O-diethyl- phosphorethioate). 50 per cent wettable powder; Vero Beach Laboratories. Compound 251hl (Bayer) (0,0, diethyl-O-p-methylsulforide- phenyl thionOphosphate). 2 pounds per gallon emulsifiable concentrate; Vero Beach Laboratories. Compound 29h93 (Bayer) (0,0-dimethyl O-(h—(methylthio)- n-tolyl phOSphorothioate). h pounds per rallon emulsifiable concentrate; Vero Beach Laboratories. Compound 3Ch9h (Not released). 2 pounds per gallon emulsifiable concentrate; G013" Chemical Corporation. Compound 30686 (Bayer) (quinoxaline-2,3-trithio- carbonate). 50 per cent wettable powder; Vero Beach Laboratories. VC-13 (O-2,h-dichloropheny1 0,0-diethyl phosphorothio- ate). 8 pounds per gallon emulsifiable concentrate; Pennsylvania Salt Manufacturing Company of Washington. ‘.’1‘.' 1‘1') "‘ “‘7'an D')’\f‘l‘n’a*"‘.'f1'n .. . J . , . . \ ._ 1 a-JJLI‘-:J-LL -.- - v.1. -1 Ll.‘iU JU'. -L.-LQ A. Observations on the biolOgy of the apple aphid. Latheson (1919) reported that Twenty Ounce PipLin variety of apples appeared to be more susceptible to injury by the apple aphid than most other varieties. Preliminary to experimentation a block of Pippins with a past history of aphid infestations was inspected weekly beginning at petal fall. water-sprouts on the scaffold limbs and new shoots at the periphery of the trees were examined to determine the presence of apple aphids. Observations revealed that the stem-mothers would locate initially on the terminal tips of new growth Po sheets. The r parthenogenetic offspring would migrate progressively inward, infesting each leaf of recent growth in relationship to the pepulation density. However, infestations seldom exceeded the fourth pair of leaves from the shoot tip. By mid-July, apple aphids had pepulated the interior water-sprouts of the current season's growth through the third pair of leaves from the terminal tips. Peripheral shoots contained colonies of apple aphids through the second pair of leaves. The described amount of infest- ation would be considered serious by commercial orchardists. B. Design of EXperiment. Because the block had received no specific all ' .5 ,J Ho O 14' Q; 0 treatments, and sufficient apple aphid populations 13 1h existed, Experiment 1(a) was initiated. This test consisted of 22 treatments (Table I) each replicated four times and randomized within the replications (Figure l). A standard method of random selection of plots was used with allowances made for variable environmental characteristics in the orchard. The four replications were designed as single—tree plot systems including two controls per replicate. Experiment II(b) consisted of 15 treatments (Table II) arranged as in Experiment I (Figure 2), with the exception of Compound 5727, which was supplied after the treatment design was established. The treatments of Experiment I were applied between the hours of ten A.L. and two P.L., and those of fixperi- mcnt II were aoplied betwee the hours of nine A.L. and one P.N. No precipitation occurred during either application (Table III). {1. All treatments were applie at a pressure of hCO pounds per square inch using a John Bean hydraulic—gun apparatus. Approximately 12 gallons of spray mixture were applied per tree. After the application of each V treatwent all parts of the Spraying mechanism were rinsed with clean water. Complete coverage was obtained by spraying in a circular pattern around each plot. (a) haterials applied July 19, 1959, at Uatervliet(3errien County), Lichigan. (b) Materials applied July 30, 1959, a* Uatervliet(3errien County), hichigan. C. Techniques of Evaluation of Control measures. Since this project involved considerable numbers of treatments, replications and small insect forms, a rapid technique for evaluation of chemical control which would be statistically sound was necessary. The problem of counting individual aphids live or dead was too time consuming; therefore, a count-rate method was devised that would provide for reliable evaluation. Five new growth shoots on the scaffold limbs and five shoots on the periphery of each plot were examined visually. The first eight leaves of each shoot were separated into four pairs. If the first pair including the tip contained more living than dead apple aphids, a count determination of one was assigned. If more live than dead aphids existed on the second pair of leaves as well as the first pair, the terminal shoot received a rating of two, and continuously for the third and fourth couplet of leaves. Each terminal had a possible maximum rating of four in all cases. Criterion for death was the brown, dried remains of the tically green in U) aphids; all live forms were characteri coloration. Since the count-ratings were made at frequent intervals, pOpulation changes were observed closely. The data was taken at seven-day intervals beginning with a pre-spray count and continued for five weeks. A subsequent lO—day examination followed the.last seven- day count. The intervals were chosen arbitrarily to closely approximate a standard spray schedule. The count-rate data per plot were avera;ed, and an analysis of variance was made (Tables IV-V) based on a comparison among all means as devised by Tukcy (1‘353).l l Referenced fr m Snedecor, 1956 p. 290. [,J .‘ Table I. Materials, formulations, quantities and code numbers for Experiment I. Amount Active Insecticide Per 100 Gallons Treatment ggterial Formulation1 of Spray Identification (g) *llb.) wtfl Diazinon 25 NP 0.37 1h Dibrom 63 as 0.50 S Dimethoate NH 33 0.25 1 Dimethoate he SC 0.50 2 Endrin 75 NP 0.25 17 Ethion 25 WP 0.50 11 Guthion 18 SC 0.30 12 Ialathion 25 JP 10.50 19 Methyl Trithion 25 Ni 0.37 15 Parathion 76 EC 0.25 20 Phosphamidon h? EC 0.25 3 Phosphamidon h9 EC 0.50 h .Phostex 2 EC 0.50 6 Ryania 100 my Lace 18 Sevin 50 JP 0.75 13 Systox 26 EC 0.19 7 Thiodan 2h EC 0.50 10 Thiodan 50 NP 0.50 8 Thiodan 50 w? 1.00 9 Trithion 25 WP “.37 16 gentrol --- --- 21,22 1 WP: wettable powder; 2 See Figure 1. EC: emulsifiable concentrate; SC: soluble concentrate. «figure 1. Plot Design of Experiment 1.1 ._.‘ Rep. I. 322! 12_ Rep. III an. I 22 2 1 22 Control 0* 17 D* 11 Ethion D* h 1h 2 Dimethoate 10 20 22 19 Malathion 2 5 13 16 Trithion 17 6 19 20 Parathion 7 12 18 6 Phostex U 22 3 1h Diazinon 6 Pfi 9 6 17 Endrin 12 11 2 18 Ryania 8 15 8 3 Phosphamidon 9 13 17 21 Control 18 16 10 13 Sevin 1h 19 7 12 Guthion 19 9 11 15 Hethyl Trithion 3 21 5 7 Systox 15 18 u 10 Thiodan 20 1 20 13“" 16 10 6 8 Thiodan 21 D* D*’ Pee l3 7 21 ‘5 Dibrmn 1h 12 1 Dimethoate 3 15’ 9 Thiodan -11- 11 A ~ 18“. 16 l glassware ...-.. 1 Each plot represents one tree; trees spaced 36 feet square. %: jot in test; D: Red Delicious, P: Twenty Ounce Pippin. Table II. Eaterials, formulations, quantities and code nurbers for Experiment 11. Amountractive Insecticide 1 Per 100 dallons Treatment 0 Katerial#fip Formulation of Spray (E‘Identificationr Tfi) (1b?) CF) Ethyl Guthion 25 EC 0.50 6 Korlan 2h EC 0.50 11 Phosdrin 25 JC 0.25 2 Sevin 75 EC 0.50 12 0 1 7d “‘09 1d W“ O to Compoun ma,a , no .2 h Compound 5539 20 SC 0.50 5 Comoound 5727 15 30 0.50 13 Compound 72“ o 50 NP 0.50 n . r", If)! ~v1 O [J Compound 23111 a“ so .20 Compound 29h93 h7 EC 0.50 9 Compound 30“0’ 25 EC 0 r’0 1 1.1 w M 3 u '9 Compound 3068) 50 WP 0.50 10 vc-13 75 as 0.50 3 Control --- —-- 1h,15 1 Y a ' '1 . - 3,. ‘ q NP dettable powder, EC- muISifiable concentrate; EC' 9 lowable concentrate. See Eisure 2. 1C Pigme2. Plot Design of Experiment 11.1 1;; ‘Rgp. 13 13 15 3 2 5 app, ;_ 10 13 P“ 12 3 8 6 LL 7 1 9 15 11 15 6 1 7 12 2 5 10 8 1h. 11 10 ll 2 12 11 a S 9 3 1 6 7 1h: 11,. WW 1 Rep. £1 13 10 Compound 5727 Compound 30686 7 Compound 22h08 P* 8 Compound 251h1 12 Sevin 15 Control 6 Ethyl Guthion 1 Compound 30h9h h Compound hh02 11 Korlan 3 vc-13 1h Control D* 2 Phosdrin 9 Compound 29h93 __”fi 5 Compound 5539 Each plot represents one tree; trees Spaced 36 feet square. *3 Not in test; D: Red Delicious, P: Twenty Ounce Pippin, . .__", -. (\J— - v ‘11 Law. L43. ’ {371113. 19 - )_ C) O .... *{3 'Jo C1“ r 1 C1— f.) Table III. Temperature and pr- September 1h, 1959, Benton Zarbor Station, Hichigan. Date Daily Precipitation Average Temperature (incheSI' (degrees Farenheit) July 19 .05 7O 20 0 67 21 0 72 22 0 76 23 1.77 73 2h Trace 72 25 0 63 26 O 66 27 0 72 28 .36 78 29 .20 79 30 .09 80 31 0 72 August 1 0 72 2 0 72 3 .27 71 h Trace 72 S O 75 -A H; ClimatolOgical Data of Vichigan, U.3. Department of Commerce, Weather Bureau. -Volume LXIIV; Kumbers 7,8,9, 1959. able III. (continued) I” 0 s0 Date Daily Precipitation Average Te perature _7 (inches) (degrees Earenheit) August 6 0 76 7 Trace 77 3 Trace 69 9 0 62 10 0 66 11 Trace 75 12 0 79 13 ' 0 80 1h 0 79 15 1.26 80 16 .13 75 17 .1h 76 18 0 71 19 0 75 20 0 80 21 0 83 22 o 83 23 .10 83 21+ 0 79 35 0 79 26 0 82 27 0 80 28 o 78 Table III. (continued) Date Daily Precipitation Average Temperature (inches) (degrees Earenheit) August 29 Trace 78 30 0 76 31 O 71!. September 1 Trace 68 2 0 7O 3 0 73 u 0 72 5 O 75 6 O 81 7 Trace 81 8 .05 75 9 O 73 10 ' O 72 ll 0 63 12 0 53 13 o 5); 1h 0 60 122333 Total Precipitation Average Temperature July 0 o o o o 20“.? inCheS . . . . . . . . o . o . 73 F. August . . . . 1.90 inches . . . , , . . 0 . . . . 760? September . . .05 inches . . . . . . . . . . . . 700F. EXPERINENTAL RESULTS The analylitical-results of EXperiment I and II are presented in Tables IV and V. An analysis of variance was performed using means.derived from the count-rate determinations. The mean values presented in the tables depict the average leaf pairs containing more live than dead apple aphids and not actual numbers of insects per leaf. Interpretation of the analysis of means for the respective treatments is facilitated by a lettering system corresponding to the significance of the results. This method provides for a rapid and accurate comparison of the individual results within a complex experiment designed to evaluate an extensive group of treatments. Any two means within a specific interval may be compared by association of the adjoining letters. Results of treatments presented in conjunction with common letters are not significantly different at the five per cent level. Means . sharing all symbols dissimilar are different significantly at five per cent. Treatments with greater mean values indicate inferior control to materials exhibiting lesser mean results, and significant differences may be ascertained readily by the letter system. Graphic analysis of per cent reduction from controls and delineation of actual mean values for those treatments of EXperiments I and II with initial effectiveness in excess of 80 per cent are presented in Figures 3 through 6. 2h Calculations of per cent reduction were based on the average of the control Loans and by a modified application of Abbot's Formula1 for the use of count-rate determinations. The per cent reductions (Figures 3,5) were derived from the numerical values depicted in Figures h and 6 respectively. per cent effectiveness (count-rate_controllf—(count-rate treatment) (Count-rate control) X 100 W Table I V 0 Material h at Various Interv Between Treatments 5 from Application mean number of leaf pairs with more live than dead apple aszdetermined for the various treatments of Experiment I. Mean Number of Leaf Pairs with more Live than Dead Apple Aphids and Significant Differences 26 iphids (PrespraY)(7 daYSY(1D daYS)(21 day§)(23 dayS)(35'dav§)(h5 days) Diazinon Dibrom Dimethoate Dimethoate Endrin Ethion Guthion Malathion Methyl,Trithion Parathion Phosphamidon Phosphamidon Phostex Ryania Sevin Systox Thiodan Thiodan Thiodan Trithion Control Control 1.65a 1.63a 1.55a l.h8a 1.70a 1.65a l.h8a 1.28a 1.30a 1.63a 1.55a 1.60a l.b3a 1.h5a 1.68a 1.78a l.28a l.h0a 1.h5a 1.25a 1.50a 1.683 OoéSbC Oo90bC 0.58bcde 0.90bc 0.38cg 0.h00 0.03fg OolSc 0.280g 0.h00 0.h50def 0.580 0.250g 0.500 0.250g 0.700 0.63de 1.03bc 0.60bcde 0.90bc 0.18eg 0.500 0.003 0.280 0.93b 1.3080 0.65bc l.05bc 0.20dg 0.580 0.10r3 0.28c 0.h30def 0.630 0.350g 0.580 0.20dg 0.230 0 0,450de 0 o 780 2.13a 1.98a 10988 108081) 1.90b 1.95b 0.95gh 0.933h 1.600 1.85b l.380e 1.500d 2.03ab 1.9Sb 1.33def 0.85h 1.98b 1.90b 1.530d 1.10fgh l.lSeg 1.18eg 0.9Sgh 1.93b 2.10ab 2.33a 2.33bc' 2.h3a 2.hhab 2.18ac 1.5013 1.83de 1.23k 1.53f 2.1309 2.30ab 2.28bcd 2.33ab 1.986f 2.2030 2.03def 2.23ab 2.38ac 2.h3a 2.20bce 2.30ab 1.58hij 1.90cd 1.23k 1.60f 2.hhab 2.hOa 2.38ac 2.38a 1.88fg 2.lSac l.h8ij 1.85de 1.70ghi 2.00de 1.78gh 2.00bcd l.h0kj 1.68f 2.28bcd 2.h0a 2.h0a0 2.25ab 2.63a 2.23ab 2.08ab 2.10a 1.708g l-SBg 1.95acd 1.98a0d 1.8Sae 1.93acd 2.03ac 2.00acd 1.75def 1.58fg 2.00a0d 1.98acd 1.9an 1.800e 1.800e 1.83bce 1.85ae 1.88a0d l .988Cd 2.03a0 2 1;Materials applied Juiy 19, 1959. Data taken; July 19, 26; August 2, 9, 16, 23; September 2, 1959. 3 Means not bearing a common letter are significantly different at the 5% level, mbans sharing any similar letter are not significantly different at the 5% level. 1“Refer to Table I for formulations and dosages. 27 Table V. Mean number of leaf pairs with more live than dead apple iphids as determined for the various treatments of Experiment II Mean Number of Leaf Pairs with more give than Dead Apple Aphids h at Various Intervals from Application and Significant Differences Material Between Treatment Tprespraym staysim days) (21 daystB daysms daysflif days} Ethyl Guthion 1.h2a 0.08d 1.12d 1.70ef 1.78de 1.75bc 0.583 Korlan 1.353 0.15d 1.320d 1.920s 2.00bc 1.8830 0.503 Phosdrin 1.603 0.18d 0.60s 1.75de 1.75de 1.8830 0.583 Sevin 1.523 0.05d 0.753 1.h2fg 1.683 1.700e 0.503 Compound hh02 l.h83 0.18d 0.70e 1.25g 1.32g 1.583 0.583 Compound 5539 1.h83 0.20d 0.75e 1.703f 1.75de 1.75bc 0.553 Compound 5727 1.183 0.08d 0.783 1.38g 1.50f 1.58e 0.h53 Compound 22h08 1.603 1.28b 2.08b 2.253b 2.0830 1.953 0.h83 Compound 251h1 l.h53 1.15b 2.05b 2.38ab 2.253 1.923b 0.603 Compound 29h93 1.603 0.h0d 1.520 2.05bcd 1.920d 1.7830 0.503 Compound 30h9h 1.553 0.38d 1.h00 1.82de 1.82de 1.8230 0.503 Compound 30686 1.323 0.720 1.520 2.1830 2.0830 1.8530 0.503 VC-13 1.523 1.10b 2.05b 2.353b 2.00bc 1.883c 0.503 Control 1.603 1.553 2.383 2.32ab 2.1030 1.903b 0.583 Control 1.553 1.603 2.353 2.h23 2.183b 1.903b 0.653 1 Materials applied July 30, 1959. 3 2 Data taken; July 30; August 6, 13, 20, 27; September 3, 13, 1959. Means not bearing 3 common letter are significantly different at the 5% level; means sharing any similar letter are not significantly different at the 5% level. h Refer to Table II for formulation and dosages. 28 Du _. i W «L. a - mwko2e mmmno>fipommmo Hmapficfi ape: maefipopws omen» mom maohpcoo Scam cowposwma name and .HH psosfiaedxm .m madman mmkdo H2300 sxa nxa axe oexe axe axe. ...xa axa axe oaxe axe axe «ca nxa 5e ouxe axe exe e a e a a _e a e n e _e a e a a. 1 1 I 1 1 J 1‘ d 1 I 1 [J 1 1 1 1 1 o .0. .ON .0m .00 ion .00 10x. . om 00 OF In. On. flnu. om N an»... an cm 3.. «00¢ mm o w w 449.6 .395 onmoxa _ oo . ZdJKOx up on. cm a. hub» 20.7339 J>Ihw 0a muqaomm: ha CO meow e>on< 2.9.2.5 29.8.22 ....mmn. Om >22. ‘IOHINOO WOHJ NOUOHGEH 1N3083d 31 .pcoo mod on m>opm mwoca>wpoemmo Hewpflcfi spa: mamflpmpma omonv pom weenie mange veep swap o>HH macs spas ended need no hangs: sees .HH pnesfinodxm .0 onswflm mthO P2300 ¢.\m nxm b~\0 0N\0 n.\0 0\0 On\~.¢.\m n\o buxo ON\0 nwxo 0\o OMS. ¢_\m nexm bflm Ovio n:...m awesome: 80m a>on< 2.2:... 2.2.20.2 ...mwk Om >437 SCIIHdV (WHO NVHl. 3N1 380W HllM SUIVd JVB‘I BBBWHN NVBW DI SCUSSION Biological Activity g£_Aphis pomi DeGeer. During l the course of this study observations were made on the biological activity of A, pgmi_in Southwestern Richigan. These facts are correlated with experimental evaluation of recently developed insecticides to provide additional know- ledge of the control of the apple aphid. Initial apple aphid pepulations were observed to be in the preposed test area during petal fall (hay 15-22). By the first week in June, the aphids had infested the interior shoot growth, through the first pair of leaves from the terminal tip. Actual counts ranged from 10 to more than 100 aphid forms per leaf pair. Reproduction had taken place by early June because some of the apple aphids present were alates. The experimental blocks had a history of serious in- festations of this pest. Cultural practices, such as extensive dormant pruning, a perennial fertilization program, and sod-mulch—cultivation produced vigorous growth of new tissue each season. Combinations of these factors with the specific host relationship of the Twenty Ounce Pippin has created an ideal environment for apple aphids. Because of increasing pepulations in recent years specific controls have been required to prevent economic losses of fruit. Chemical choices were dormant oils and l r "I ‘ Lay—sentember , 1959 . to P-J dinitro-compounds with the inclusion of aphicides during the growing season. The constant use of conventional dosages of parathion as a preventative measure for increases in aphid pepulations became less successful and more costly each year. The need for efficient aphicides had become important. Actual counts of £3 pgmi pepulations were continued through June, but as infestations increased, counting procedures became cumbersome. Pepulation densities of aphids resulted from prolonged migration of both alate and apterous forms to actively growing tissue. The adult aphids seldom were observed beyond the fifth pair of leaves from a terminal tip; consequently, active colonies of £3 pgmi_were located consistently nearest the shoot tips. Parthenogenetic young invariably fed on newly expanded leaves, crowded between the tip and fourth pair of leaves. Factors such as migration, intense feeding and rapid plant growth have created the necessity of systemic compounds. The method of population sampling used in these experiments was based on the biological activities of g, 223i, with special emphasis on feeding habits. The count-rate technique was designed for rapid evaluation of surface residual and systemic-type aphicides; and, also to provide a practical sampling procedure. By mid-Ju1y count-ratings from the peripheral area of several trees averaged one and means of water-sprout counts equaled two. Since the pepulation density had attained .> 1 [5.]. sufficient proportions to cause foliage and fruit injury the experimental treatments were applied. The apple aphid is an economically important insect, generally being categorized as a nuisance pest. In the plots, the aphids were persiStent. Wherever consistent control was not obtained several types of injury usually occurred. Excreted matter on fruits was the most serious, Fluid-like and sticky, this substance became discolored by a secondary fungus growth which reduced the ma ket value of many fruits. Excessive feeding had caused terminal die back and leaf drop; and some fruit did not attain mature size or color as a direct result of aphid damage. Therefore, since the apple a hid is considered more of a nuisance than a serious apple pest, it is logical to assume that control methods should not be disproportionate economically to the degree of injury. Pepulation densities of apple aphids had attained maximum values during mid-August (Figures h, 6). This increase which was in Opposition to the results of chemical treatments indicated an ideal testing of the materials. Infestations declined rapid y following the peak. The prime factors for these population decreases were lack of precip- itation, temperatures in excess of the normal (Table III) and maturity of plant tissue. Evaluation of Chemical Controls. A detailed statistical analysis was made of the treatment data. The application of significant difference constants to the ranked means of km) \51 treatments for the various intervals sparating the means provided a rigorous statistical proof of the merits of the evaluated materials. This method will produce reliable conclusions from exaerimental results if the sampling techniques accurately represent the population. A condensed description of analyzed data can be complicated by the many comparisons possible among the means of the treatments. Therefore, a lettering system was attached to the mean values. This method simplified the interpretation of the data in terms of significant difference. Because Experiments I and II were autonomous no comparative conclusions were made. The experiments were not repeated because duplicate field and environmental conditions were unobtainable. However, the data from the statistical analysis permits reasonable expression of confidence that if the treatments were reproduced, comparable results would occur. Therefore, a quantity of insecticides was evaluated exposed to similar field conditions in the antici.ation of providing a wide range of information concerning chemical control of apple aahids. Materials with outstanding aphicidal preperties from EXperiment I (Table IV) were Dimethoate, Phosphamidon and Thiodan. Each of these chemicals provided commercial control through 21 days from date of application. Commercial control is defined herein as equivalent to 1.5 or less mean count rates. Increased dosages of Dimethoate and Phosphamidon were successful for at least four weeks. All materials with the exception of Diazinon, Dibrom, Kethyl Trithion, Parathion, d‘ 0 FS yo p *O’ H H. I The tex and Ryania produced control for 1H days af C.) cation. There were significant differences between Dimethoate and Phosphamidon and the controls at the MS day interval, but 1 in all treatments population densities exceeded commercial Dimethoate, Phosphamidon and Systox exhibited systemic qualities with extended residual activity, since plant growth dilution and continuous aphid migratiOn eliminated the possi- bility of surface ceitact control. Results from the maximum rate of Thiodan indicated a possibility of systemic activity. .5 I. Experiment II several compounds were tested for aphid ’_ u control for the first time (Table V). Phosdrin and Sevin were established as standard materials for comparison. Results were generally disappointing, since compounds 22h08, ZSlhl and VC-l3 were not effective. Ethyl Guthion, Korlan, Compound 29h93, 30h9h and 30683 produced partial control with ineffective resid‘al activity seven days after application. Compound 5V39 compared favorably with the stand- ards, but acceptable control did not continue beyond two weeks. Only Compounds bFOB and S727 exhibited extended aphicidal properties. 1 reveals the From these experiments examination of data fa t that surface-residual materials were limited in duration of control primarily because of plant growth and reinfestation. Hewever, several of tie compounds could be included satisfactorily in a commercial control program. The obvious Refer to Tables IV,V and Figures 3,5. \ ) -4 choice should be systenics since the longevity of aphicidal preperties reduces the necessity of frequent applications. Kethod of Sampling. The accuracy in analysis of variance ! _. . and subsequent application of statistical devices is dependent on the sampling method utilized for data collection. When the sampling techniques reflect a true random section of the c;- Ho parameter ponilation, the sta stical procedures will produce an accurate potrayal of the effects of tae variable tested. Madsen and Bailey (1959) reported on apple aphid control using total numbers of dead and live forms on a single leaf as criterion for evaluation. However, their method entailed extensive counting procedures and failed to account for trans- location factors of systemic materials. The technique applied in this research was an attempttn sample the entire population of apple aphids for each termina . Because the count-rate method included the expanding terminal tips the system was applicable to cases of translocated materials. Therefore, it would be reasonable to assume that since the count—rate ficthod was rapid and reliable, the technique could have practical implications. Growers troubled by apple aphid problems in their orchards could estimate easily the necessity of chemical control by applying the principles of this method. 12*? Eva? count—(1:73 This inve ti ga.tion is briefly summarized as follows: 1. The biolo Qcal act 1vity of the apple aphid, Aphis pgmi_De' deer, in a Southwestern Nichigan orchard was observed during the growing season of 1959. Distribution and feeding habits were correlated with chemical control experiments. 2. A group of 28 insecticides were evaluated on Twenty Ounce Pippin variety of apples. Performance data wez e analyzed statistically; control merits were established by comparison [a 01 signif icant diffe; ences among the treatnent means. 3. A rapid method of sampling parameter pepulations was developed to facilitate the evaluation of the chemicals for apple aphid control. he following conclusions were drawn from the results of this research: 1. Apple a: hids prefer feeding on succulent foliag and continuously digrate to newly xpanded leaves. 2. The insect is economically important because of its persistent occurrence. Several types of injury result if consistent control is not obtained. o‘ 3. Aphid populations increased to treatment preportions by mid-July. Peak period occurred durirg mid-Aurust. Inf st- ..J ations declined rapidly following the peak. h. Insecticides outstandi1ng for chemical control of the apple aphid were: Dimethoate, Phosphamidon, Systox, Thiodan, Compounds hh02 and 5727. N no of the materials 38 ‘ tested a monstrated satisfactory control in excess of four weeks after treatment. 5. Chemicals exhibiting systemic properties with ex- tended residual activity gave the best control. Surface residual compounds were limited in ffectiveness by plant growth dilution and reinfestetion. 6. Count-rate determinations represented an accurate S :3 mpling of the parameter pepulation. Statistical procedures for proof of significance were applicable to count-rate data. 7. The count-rate method for evaluation of apple aphid control elimi ates actual determinations of aphid numbers. Technique is rapid, accurate and dractical for usage by commercial app e viewers. L‘ \l -.TI JRaTI IIB CITED M , A. C. and N. E. Turner 1917. Lorphology and biolOgy of the green apple aphis. Jour. Agr. Res. 5: 956-990. Brittain, W. II. 1915. The green apple aphis. Annual Rept. Nova A. Scotia Fruit Grower's Assn. 51: 4,{)- m5 Outright, C. R. 1953. Controlling Anuraphis roseus and Aphis pomi. Jour. Econ. E'nt. hE': 379-38I. 1959. Rotational use of spra y chemicals. Jour. Econ. Ent. 52: h32- '13h. he apple plant louse. Country Gentlemen. 0 I856. Third report on the noxious and other insects of the state of New York. Trans. New York State Agr. Soc. 16: 3lS-h90. German, P. 1959. E? periments in apple insect control. Jour Econ. Ent. S2: 826- 828. Glass, E H. and P. J. Chapman W55. Summer control of the apple aphid. Jour. Econ. Hodgkiss, H. E. ~1919. Control of the green apple aphis in bearing orchards. New York Agr. Expt. Sta. Bul. Ho. h6l; 97-l3h. Hottes, E. C. and T. H. Frison 1931. The plant lice, or Aphiidae of Illinois. Bul. Illinois Hatural History Survey. 19: 1CC-hh7. Madsen, H. F. and J. E. Bailey 1959. Control of the apple aphid and the ro:.y apple aphid with new Sr: ay chemicals. Jour. Econ. 3111:. 52: ,103-1 './'Jo b0 so 1919. A study of the plant lice inj tryini the Io“: and fruit of the apple. Cornell Cniv. Afr. ‘fi ~ .-.. ° ‘.T‘ . / P’,’ Exp. Sta., 1.8-101? _.O. 23.1-, 077-132. II. ['0 .' 811C 1f ul insects. ICC-ra. 3'11 Hetcalf, C. L., N. P. Flint on 1-1 ork. 1071 pp. 1951. Destructive and is I at, P. J., H. E. Hodgkiss and F. H. Lathrop 1916. Plant lice injurious to apple orchards. I. New York Aggr. £11113. Sta. Bul. 1.0. 145; 11-5 Patch, E. E. 192 . The summer food plants of the green apple aphid (A his pomi). Eaine Agr. Expt. Sta. Bul. Ho. §I§s h5-68. Peairs, In 72. 1950. Insect pests of farm, garden, and orchard. John Kiley and Sons, Inc. New York, 559 pp. Peterson, A. 191;. Some studies on the eggs of im.porta nt npwlc * ant lice. New Jersey Agr. Expt. St. Bul. ITO. 3320 '63 pr). Steiner, L. F. 19h4. Residual effect of DDT Sprays on early spring apple aphids. Jour. Econ. Ent. 37: 560-561. Smith, J. B. 19CO. The apple plant louse. New Jersey Agr. Expt. Sta. Eul. No. 1M3. 23 Sned ecor, G. W. 1956. Statistical methods. Iowa "tate College Press, Axes, Iowa. 53h pp. MICHIGAN STATE UNIVERSITY LIBRAR.| ES