A cwmmson car- METHODS Am MATERMLS USED m GREENHOUSE MST camam I’finfs {ar- iho Degree sf M‘ S. MICWGAN STATE COLLEGE Ema-{é Frank Bash: 1952 This is to certify that the thesis entitled A COMPARISON OF METHODS AND MATERIALS USED IN GIEEIIIYOUSE PEST CONTROL presented bg Harold Frank Beltz has been accepted towards fulfillment of the requirements for M . S . degree in Ent omolo my fl 7mm f whim“ professnr Date March 7, 1952 0-169 A COMPARISON OF METHODS AND MATERIALS USED IN GREENHOVSE PSST CONTROL By Harold Frank Beltz ;; A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of lMSTER OF SCIENCE Department of Entomology 11-:th ACKTJ OVLE DG TENT S The author would like to express his sincere appreciation to Professor Ray Hutson for his co- operation and advice; to Dr. J. R. Hoffman for his constant assistance and for the use of the green- house space; to Dr. E. King; for his guidance and assistance in the writing of this thesis; and to his wife, Audrey Beltz, for the preliminary typing of this manuscript. #********** ********* ******* ***** *** * r» r‘ -—' “in." ,. i t'fii ‘ I. | ,d‘. l '5 ‘ ~03 TABLS OF COVTEWTS I. II‘ITEzoDTICTIOI‘I..............................C.............. II. va/rIF-‘r-AJ OE? IJITBP‘JXTTTRE.....C...O.C.O.O........C............ III. IImTEI-{IALIS IJSEDOOCOOOOOOOOOOOOO0......OOOOOOOOOOOOOOOOOOOO Ii]. E:P5‘J:I~TE1,TAL 1.'ErFElODSOOo00.00.000000.00.000.0000000000o... PeSt IHVOlvedQOoooooooooooooocoooooooooooooooooooooooo FomllatiOn-S ITSed..................................... Aerosol Treatments...’.O......................O.... Under Laboratory Conditions..................... T{TilliClelf' ACtllal Growing Conditions...coo-000000000. Determination Of ihterial ReqUiredooooooooooo Loading the BOTnbooooooooooo.000.000.00.000... Determination of Capacity of House........... Determination of Amount of material to ”39... Determination of Time Remiired to Discharge I{eqllired mount...............o.C....'0'... Application Of AerOSOlooo00.00.000.0000000000 80m}, Treatments................................... ‘ Under Laboratory Conditions..................... Under Growing Conditions........................ Pressure FumigatorSOOOOOOOOOOOOOOOOO00.00.00.000... Under Laboratory conditionSoooQOOonooooo0000.000 Tander GrOl'Jing Conditions....o.. coo-0.00.00.00.00 SE-rstemic T-hteriaJ-SOOOOOOOOOOOOOOOOOOOOOOIOOOO00.... Waterials Applied to Steam Pipes................... Slug contrOI TestSOOOOCOOOOOOOOOOODOOOOOI.I.00.0... V. RESTTKPSOIOOOOOOO0.000.000.0000.0.0.000...OOOOOOOQDOOOOOOO Figures and Tables 0 o O O O O O O O O O O O O I O O O O O O O O O O O O O O O O O O O O 0 VI . DISCTTSSIOIJ CI?" PLBSTTLTS. O O O O O I O O O C O O 0 O O O O O O O O I O O O O O I 0 O O O O O 0 Evaluation of “aterials............................... Page 10 19 19 19 19 19 22 23 23 3O 30 30 31 33 33 33 35 35 35 37 37 39 44 44 91 91 TABLE OF CONTENTS (Continued) Page Against Aphids..................................... 91 Against Adult Healybugs............................ 92 Against Vealybug Crawlers.......................... 93 Against Slugs...................................... 94 Against Hites...................................... 95 Against Adults of Soft Brown Scale................. 96 Against Crawlers of Soft Brown Scale............... 97 Evaluation of Nethods................................. 99 VII. STIR'railquOOOOOOOOOOOOOOOOOOOOIOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 103 VIII. LITBFHAETTL‘L‘E CITE,DOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOIOOOOC 108 I . INTRODUCTION I. INTRODUCTION The annual crop of the greenhouse industry is valued at nearly $100,000,000.00, nationally and annually this valuable crop consisting of vegetables, flowers, houseplants and other ornamentals are subjected to attacks by the numerous pests that take advantage of the constantly con- trolled temperature, moisture and other such conditions maintained in the greenhouse. Important among these pests are the mites, soft brown scale, mealy bugs, aphids and last but not least, the slugs. In the past soft brown scale has not been a very serious pest but since the advent of parathion, which kills off the parasites of the soft brown scale without harming the scale itself, it has become a past of quite some importance and one that is not easily controlled. The slugs, like the soft brown scale, have not been a very serious pest in the past but today they show every indication of becoming one of the most important pests in the greenhouse. The control of mites seems an endless task. ‘hny new miticides have been developed during the last five years in the hope that, at last, a thorough and a permanent control could be obtained. In regard to the mealy bugs and aphids it can only be said that with the many insecticides on the market today the mealy bugs and the aphids are still plentiful and destructive in greenhouses. 'With fliese problems in mind the writer has taken over 40 different insecticides, miticides and molluscacides and tested them in the green- house under actual growing conditions. Some of these materials have, in one form or another, been used in the greenhouse control program for quite some time but the majority of the materials are still in the experimental stage. Different forms of these materials and different methods of ap- plication were used and compared. Laboratory experiments were carried out in.the entomology greenhouse. A pure culture of parathion-resistant mites obtained from.various com- mercial greenhouses throughout the state were used in the experiments. This culture of parathion-resistant mites was kept isolated throughout the experiments. Cultures of soft brown scale, mealy bugs, aphids and slugs were obtained and kept in file same manner as were the mites. The materials showing promise under laboratory conditions were then tried under'actual growing conditions when infestations occurred in.the plant science greenhouses, the botany greenhouses and the horticulture greenhouses located on.the campus at Michigan State College. II. REVIEW OF LITERATURE II. REVIEW OF LITERATURE During the past few years many new insecticides, acaricides and molluscacides have been developed for the special purpose of pest control in the greenhouse. The claims of the various commercial companies con- cerning their products are usually encouraging, but the reports of the various investigators who have tested these materials are not always as assuring. Nevertheless, their work indicates that certain of the materials show great promise. Literature concerning the development of insect resistance to in- secticides is plentiful. A summary of the literature was reported by Babers (2) of the United States Department of Agriculture. It could not be determined whether resistance was due to stronger insects or due to a specific chemical. It appeared that certain strains of insects gave rise to resistant progeny; however, there were others that did not. Sufficient evidence had not been produced to provide a theory of resistance although certain conclusions were drawn regarding differences in strains, factors inherited through the Mendelian laws, factors due to cytoplasmic changes, and factors associated with morphological and physiological differences. Although no clear explanation of resistance could be given, evidence seemed to be in favor of a gradually increased resistance rather than a specific resistance. Hexathyltetraphosphate was the first organic phosphate to be used successfully for the control of the two-spotted spider mite. This was followed in 1948 by parathion which controlled the mites with less frequent applications. However, a few greenhouses reported poor results from.the use of parathion and hexaethyltetraphosphate. This led to a series of investigations by Fulton and Smith (24) which showed that two strains of mites existed. In tests against the parathion resistant mites it was found that these mites were also resistant to some extent to eight other organic phosphates and to, l,1-bis(p-chlorophenyl) ethanol, , 2-(pdtert- butylphenoxy) l-methylethyl 2-chloroethyl sulfite and to p-chlorophenyl p-chlorobenzene sulfonate. The resistant mites were most effectively controlled with tetraethyl dithiopyrophosphate, octamethyl pyrophosphor- amide and p—chlorophenyl p-chlorobenzene sulfonate. Previously, Garman (10) had reported that resistant mites on roses lost practically all of their resistance when reared on beans for approximately four months and Neiswander (15) had reported that the rate of development and the degree of susceptibility to the various acaricides was influenced by the host plant. However, Smith and Fulton (24) took rose-reared resistant mites and reared them on beans and on rose for ten months and after experimenta- tion found that the resistance persisted through the succeeding generations. Garman (10) found that a species resistant to one organic phosphate was not necessarily resistant to another, and that some food element may be the important factor as was the case when the mites were transferred from roses to beans. It was further noted that even after the most in- tensive aerosol treatments with p-chlorophenyl p-chlorobenzene sulfonate, tetraethyl dithiopyrophosphate, parathion and hexaethyltetraphosphate live mites and eggs could always be found and it was possible for these to increase to epidemic proportions after a year or two with one par- ticular chemical control. l l l“‘ l I I ll C. R. Neiswander and others (15) found wide differences among various colonies of the two-spotted spider mite. In their experiments, carried out at the Ohio Agricultural Experiment Station, they found that the rate at which the mites developed and the rate at which they were eliminated by the application of acaricides were affected by the host plants on which the mites fed. Tests were also made in which a dilute acaricide was applied to three or more generations of mites. At the end of this time these mites had developed some resistance to that particular acaricide. They concluded that for effective control the acaricides should be changed at frequent intervals. Blauvelt (4) undertook extensive experimentation of azobenzene for the control of spider mites on rose, as this pest is difficult to control on fidese plants. The mortality counts due to azobenzene were high but roses were susceptible to various types of insecticide injury such as burning of soft growth, yellowing and dropping of mature leaves, and stunt- ing of growth. Blauvelt found that one disadvantage of azobenzene was the loss of color of red and pink varieties of roses. Most of the injury from.azobenzene fumigation appeared to be caused by unfavorable conditions. Numerous azobenzene treatments were applied without foilage injury of any kind. Hamilton (12) found that azobenzene could be applied as a dust. The dust volatilized slowly and if it was applied to the lower surface of the leaves where mites usually fed or applied in dense foilage that held the fumes, it would control mites nearly as well as the azobenzene fumigation treatment. English (7) using azobenzene as a supplement to parathion, tetraethyl pyrophosphate and tetraethyl dithiopyrophosphate aerosols ran a number of tests to determine the value of azobenzene in these three types of aero- sols. Using parathion at one gram per thousand cubic feet he obtained a kill of sixty per cent and when.this was supplemented with azobenzene the kill was increased to one hundred per cent. Similar results were obtained by using tetraethyl pyrophosphate plus azobenzene and tetraethyl dithio- pyrophosphate plus azobenzene. Pritchard and Beer (16) found that the young stages as well as the adults of certain species of scale were susceptible to parathion sprays. However, the adults of Coccus hesperidum were not affected. Against mealy bugs parathion proved very effective, especially against those species which are ovoviviparous and live exposed. Those having egg sacs and living under sheaths were not easy to control. The Pittsburgh Agricultural Chemical Company (31) after a series of research studies and process developments involving Hetacide reported that this material had the insecticidal strength of parathion.while being far less toxic to mammals. It was used against those insects that are gener- ally controlled by parathion. Further studies concerning this material ‘were undertaken by the Dow Chemdcal Company (30) which reported Mbtacide excellent as an insecticide but not quite as effective as a miticide. It was also found that the longevity of the residue was intermediate between tetraethyl pyrophosphate and parathion, and that Metacide, although dis- appearing from the surface of the treated leaves in a few hours, remained effective in the plant tissue from two to four days. Because of the interest in finding an effective aerosol for the re- sistant spider mite Smith and Fulton (23) conducted tests in which they compared the effectiveness of five per cent tetraethyl pyrophosphate, ten per cent parathion and ten per cent tetraethyl pyrophosphate. The tetraethyl dithiopyrophosphate aerosol was the most effective of the three. It was also toxic to aphids, white flies and mealy bugs while being relatively low in phytotoxicity. . Armstrong (1) conducted laboratory experiments on the toxicity of para- chlorophenyl para-chlorobenzene (K-6451) in the form of a 50 per cent wettable powder. It was slow in action but very effective against the two— spotted mite. It destroyed many of the eggs and many of the immature forms while permitting the mature forms to survive and continue to lay large amounts of eggs. However, these eggs, according to Armstrong, failed to hatch. He found it compatible with all the common insecticides and fungicides. The Julius Hyman Company (35) reported outstanding results obtained with dieldrin against certain insects. It has shown promise of being effective against a wider variety of pests than older materials. Its value is in the control of those pests for which a long residual effective- ness is desired. In the greenhouse it was particularly effective against ants, flies, thrips and soil pests. Outstanding results with aldrin have also been reported by the Julius Hyman Company (36). Its properties are much the same as those of dieldrin, except that it has less residual action. Bussart and Schor (5) of the Velsicol Corporation investigated the value of chlordane. They found it effective against many different pests. I ll! I." I I'll-ll l ll.l| I ll The most promising results concerned the use of chlordane as a soil in- secticide, for the control of such insects as wireworms, white grubs and cutworms. It has caused little or no injury to plants, even on the cucurbits which are especially vulnerable to chemical injury. wallace (27) reported that when.Pestox, in an aqueous solution, was applied on the foilage, only a small amount was absorbed into the cell sap and that this occurred slowly. When applied to the soil Poster'was readily translocated upward. However, these tests do not indicate the effects of Pestox under normal growing conditions. Reports from the Pittsburgh Agricultural Company (32) indicate that Potosan is particularly effective against certain species of mites. The action of Potosan against other insects has not been determined. Systox, a neW'systemic insecticide, was found by the Pittsburgh Agri- cultural Company (34) to be more effective than octamethylpyrophosphor- amide. Systox was another of the organic phosphates developed by Dr. Gehardt Schrader. It has shown an exceptional ability to penetrate plants by entering into seeds, roots or leaves. Reports indicate that it has remained in.the plants for long periods, killing aphids, mites and certain chewing insects. When applied as a spray it gave kills at much lower con- centrations than parathion and the sprayed plants remained toxic for long periods of time. It was also shown to possess the properties of a fumigant as well as killing systemically and by contact. White (28) carried out tests using sodium.selenate against spider mites on carnations. The sodium selenate was dissolved in water at the rate of one gram per gallon and'then applied to the soil. It was also used -8- by impregnating superphosphate with two per cent sodium selenate and then applying this mixture to the soil. Both of these methods gave good control and caused no injury to the plants. Visible effects of the toxic action of sodium selenate were apparent after four weeks. -9- III . MATERIALS USED masowEeno opedmnoz mHmoflEeno opnsmnofi use .mpoo mpooo loam pnoam .oo Hoe unsono gem .me owes so wopmwa one wfiewaepor has \\\\\0mmmu owmmo \\\\\\\0m «02 \\\\\ , 0 cm epsnmmonmoazm Haapoanpoe OMHMHHVVm \fl manganese none» Hogans Ioapwsssasmlo Heavens .o.o epsnmmonm ISaaoEfin Haaposupme Ho illloullmllll Ho epdsomazmencunep = oa0H50Isawm o Hanonmoaoanondadm mo mQOflpsapnooso O *- Homoae< Rea page RH was menace maneppem.wma* .Homoao< Rea Howoae< Rm one hopowflfism oaommopm Rafi Homoaoe flea one season caneppe§.mom* anemones .mmae dowfipdhwm mome Hmvmlx busgfioo eHnEhom Hsowawmfim no Heasposapm ossz HwOfiaono noapeanfihom oeaz.sofifioo -10- .omH mama so woymwfi one deHaope: hwamm mo wnofipwapneonoo * .maoo HsOwEeno m was b easemenonoflno mposooam Ho Ho sfiapIHssonm sensed lam oooaeoe b uneuonoEoE Snapper an? 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Haefisaae «V eoflEsaonmmone nomad Hknpgtwpoo eponmmoneooflfidflv afihnpeEsapop fiancee Iwonmownphxonpowm mopemeSm chowmoam KOH opsapnoocOo ensaaa manna Ianfim wfi.mw* open» Ineosoo oflzdwfi eHnHmHSEm RH.mm* one Howoace VOH Howoue< ROH @551. MIOO 0H *3 a 9-" seaflum .xopmam. 4 orth \/ J \‘ } South Figure 1h. Air movement in cross section of the house, ., / V7 ”99“ t l 7 East \ ,/ d ‘¢—“—- 4___. .__' .,,., Figure 15. Air movenent lengthwise of house. Percent 100 g B. l i so , PM i (10 l I I 70 l l t l l I I I | 90 \Lo 30 \) H 41’ Ci‘ectiVGHQSW Of ”a-taifl Jrganic Figure 16 ' Thosnn-tes Ag‘inst Aphids " Control /\7 I." 7‘ ‘ ——-~— /1/ 77":::l;:;:><:::; W C \ I{\\V/ I A. TEPP Aerosol B. TEPP Spray C. Metacide Spray D. Tetra n proryl dithiono perphosnhate Aerosol S 10 1% 20 23 30 Number of Days uxnosure To Material An average 3% kill in check Figure 17. Effectiveness of Certain Organic Phosphates Against Aphidses Percent Control 100 90 80 7Q 60 50 if] A. Parathion Aerosol 7'.“ H“ B. Parathion Spray '10 1'?! m? C. TEDP Pressure Fumigator %/ D. TEDP Aerosol 30 "g! I“ E. Dimethyl Paranitronhenyl M thionophosnhate Aerosol iii 20 HI #1; F 10 i 0 5 10 15 20 95 30 Number of Days Exposure To Material *An average 33 kill in check Figure 18. Effectiveness of Certain Nicotine FPO‘hlctw Against Aphids r Percent Control L D /\‘ \ 100 I ,, *———~____ I l‘\/ ('1’) I I I ' I I, . | I 80 I I I 70 : I I I, I 60| | I . I 50; I A. Black Leaf hO' plus led I! Arrow Spray II B. Black Leaf MO' Srray 3.10.1 [J C. Black Leaf 9" Aerosol m NI D. Black Leaf 00' Iressure 3OHI Fumigator m 1I W :70" E III H III 18w 0 j 19 1; 70 25 30 Number of Days Exoosure To Material r I *An average 5. kill in check Figure 19. Effectiveness of Certain SyStemics Against Anhidss Percent Control 10) 8O 7O 60 / / , - ' / //',, I JL/// /.”' SO / //' A. Potosan Spray ////’ ,//{ B. Sodilm Selenate Apvlied // / x7 to soil ,',/ IL) / .’ j] I / ’// C . OI'IPA Suray /// / /// D. OHPA Aerosol 3O / );/ fl 0 q . / ,* b. oystox Spray / y’/ 20 I:’/ I 1“" __ _/ / I I, .f" “ho-”x ,’ y} / ’/.," / 10 )5], / op '3 10 1F: so 25’ .. 30 Number of Dave Exnosure To Material .4. w *An average 3a {ill in caeck ”o _anto Figure 20. Effectiveness of Certain u,ns ‘7 Percent Control 103 "~ ‘- ‘ ‘ (x/\P(// \“““C‘ h‘>/‘74¥:TE= ‘~~-‘____,* ________ 3/ \/ N D (.. \ o I] \\ I I II \7\ \ I 80 I \ ' I 70 ' . H I I I (JO | I' . 43307 1 I A, Monsanto Ciemical...- Aeroso I 50 II B. Monsanto Chemicl Eda-3 Aerosol I II II c. Honsqnto Chemical ” 876.Aerosal ‘ II \I‘ L0 II I H 30 w II I II 20 b I I I 10I h OJ. 3O 0 r)’ 1.”) 1:; ‘0 Number of Days Exposure To Material *An average 6% kill in check Figure 21. Percent Control A L) 109 3 Ir/v-"’ ” I oo II I I 80 I I I l 70 ' I H 60 I I I I. SW III) 30 — —_ —— ———————— — -- —-- --_ --I -—-—_ _“-.. ——- —_v-.- .10 %An average a of H0h9 Against Arhidss Effectivenes A. EOHQ Nettable Powder 3. HOK9 Emulsible Liquid C. h9h9 Aerosol 10 13 20 7; Number of Days Exposure To ”qterial 33 kill in check 30 Figure 2?. Effectiveness of K-GHSI Against Adults of Soft Brown Scalo* Percent Control 100 90 [L ’ / ( / O / . 73 ///l to ’ SO I .- A. A-éhgl Aerosol B. K-éfiql Snrqy ‘LO / 30 7‘0 I 10 1’ 0 3 10 15 so 25 Number of Days EXposure To M1t071fil *An average 33 kill in check ... V« 30 ‘1 ”1‘393. U‘fe~t?venoss of ”73? féqinst A (V 4. 7‘“ n n V Ldults of oo_, grown no le w Iercent C ntrol 103 . /______..__-_- OO 80 T33? ?ressure Inuigwtor TYDP Aerosol HO 10 13 “o “f 30 Number of 31y" Exrosu'o To Kateriol ‘ I 1 W *nn qvorqge 39 £111 in cneck fiqunSt FigureZH. Tffeotivoness of MGR fidfilfs of Soft Brown Scalefi Iorcent Control " 10\ “0 in, I If“ I f , / if) I, A. 'l.r“Lq “vett’bIC:PO"'deP l \\\, B. mono Emulsible Linuid l l 37‘! C. M‘HC Aerosol 30', 10 1i fig 30 \II A Thrflyar of“%un3i31rosuro TR)‘?Iter111 l ‘ I \ o 1 . n 'IVCI‘I-‘fe 3) 111- in cqeo}: of Certain Systemics PS iffectiveness Soft Brown Scale* 3 . qulnst Cr-wlers of Percent Control A. 0L 1"; SDPQY l I B. OHPA Aerosol MO I. C. Systox Spray 3oI O H 19 177 7T." 7’5 30 s Number of Days Exrosure To I'I’Hin'r‘iql 3.4% .1 ‘ "Akn qvepage 1:111 Of 3’) in CHGCk Figure T6. VTTeotlvenoss of Cewtqln Org n10 Thosrhstes Loq3n1t Crawlers of Soft Brown 30T10fi - Percent Control TTPP Snrqv TSP? Aerorol Parqthion Crrqy Parethion forenol T71? T-essure l‘nfilgfltor TED? Aerosol JUOUJID L: o '11 k3 ; A- 30 L‘AA AA P) a A v ._ \ § \ x \ u ‘ 9 Q 1" 1! /' "‘1 .’ / 1’ If H ,l ” <1! ”’ I v Jl’,’ " ,' ,4 .4 '-......--.." ‘3 1’.) 1‘) 9r) 0 " 30 Number of Days Emposure To Material *Rn averqqe 3, kill in check Piqure ?7. Sfpectiveness of D.D,T. Against Crawlers of Soft Brown Scale % Percent Control 100 80 77' To A. 3.3.T. SDPaY O b 10 15 20 ?5 Number of Days Exnosure To Material fifin average 3; kill in check 30 Figure 98. Effectivenes~ of ROHQ {sainst Crawlers of Soft Brown Scale “ Iercent Control d" y..- __—." 100 ' ,,,,, A z’ll *3 !_/‘_________._- ,0 1’ 4 80 ' /__—_—‘L“\\~\ : / ~\ $0 I 30 I! L. ECE‘ Yettable Fomder {I B. M019 Emulsible Liquid "L9 I] C, HIM“ [(330801 30 ll !/ I ‘ S 10 1'; "s ; 25’ 30 Number of Days Exposure To Material I - I tun average 2» kill in check Figure C“. Effectiveness of £46131 fiqainst Crawlers of Soft Drown Scale % Percent Control (0 I r .:_, J K-éhgl Spray / B. K-éhSl Aerosol o 5 10 .15 :70 "Q \i 1 3O 3 I Number of Days stnosure To Material go ‘. , _ I s g wan average ?o £111 in cneck Figure 30. Effectiveness of Certain Organic Thosrhates \ Against Adults of Healvbugs Percent Control ‘: A. TEDP Treasure Fumigator '3 m‘w '- A u. lnDJ LCPOSOT C. Pirathion Snrav W. Parathion Aerosol E. T4PP Snrflv F. Aerosol TEPP J 5 13 13 ?O ”J 30 Nunbcr of Days Exnosuae To Iaterial :An average 35 kill in check Figure 31. C‘fectiveness of Certain Etherimental Materials aninst Ldult Uealybugs ” Percent Control 90 'fl/ —————— \‘\\‘\3\\ C\ 80 A. HOHC Wettable Po"der B. wow“ Emulsible Liquid C. uOHQ fierosol D. Monsanto Chemical 30' #3897 Aerosol 70’ I’ll: 1" 7o 21 30 ) 1o 0 U1 Number of Days anosure To Material . .I ‘ ‘ run average 3) :ill in oneck Figure 3?. Uffoctivonosa of Certain TInesimental Xateaials Against Cravlers of Mealybags “ Percent Control 10'l 0 -~ '~‘ 9 \\ “ ‘ “ ‘ 80 7O 6.0 A. Honsanto Chemical £3fl97 Aerosol B. RWMO wettable Powder C. HDHQ Emulsible Lieuid D. ECHO Aerosol ‘1 10 15? so 75’ 30 Number of Days Ex osure To Material . 4 tAn average hp kill in check Figure 33. Effectiveness of TEDP Against Crawlers of Mealybug Percent Control 100 90 70‘ A. TTDP Aerosol B. TCDP Pressure Fumigator S 10 15 20 $5 30 number of Days Exposure To Eaterial .. .- J ‘ wan average 2p kill in Chect Figure 3k foectiveness of System [gainst Crawlers of Hea‘vbug .Percent Control 100 B0 80 7O 60 3O 2O 10 01 5 10 15 Number of Days Exrosure at I ‘ O V 1 wfln average k) Jill in caecc m l O 9O I T L A. Systot Spray aterial 9% 3O Figure 35. Effectiveness of Certain Orqanic PhOSphates Against Crawlers of Mealvbug,l Percent Control 100 93 80 7O 60 A. TEPP Aerosol B. TEPP Spray C. Parathion Aerosol D. Parathién Spray 10 15 20 25 30 U1 Number of Days Exposure To Material eAn average 23 kill in check quinfit Mikes .pcent anhP01 B .00 I/ 80 70 l 60 :I 1 qt’)? Fun on ‘ -~n caure l A. D30 {'6 ’ 50 i B. DMC Aerosol 11d awmlsible Lim :' c Dimite “ l | 0 l 3 H l l PO I | l' 0 10 | c 3- 1 1c 90 2’ I 10 j J 5 erosure To Material eck e B": kill *n Ch it"s.“ qver‘qfl' Fiaure 3?. Effectiveness of K-ohgl Against Mites % Percent Control 100 r)0 80 70 A/’/ / 60 5’0 I / l / / / ho ’ / I / / - / 3O / / // 20 \,// / / I / / 10 , / / / ....... / s 10 A. K-6h51 Aerosol 8. K-6H51 Sprav C. K—éhgl Annlied to Steam Fines 13 ?O ?5 3O Numbe" of Days Exnosure To Material tAn average 63 kill in check Figure 38. Effectiveness of Certain Svstemics Against Mites * Percent Control lOO . ‘_____ C / ...— ####### -—-"' M ————— A ————— 90 . ’/\\/—/fi/ x ~\B'—~ ~ / / ./, I /// 80 / / / / // 70 / // / / 60 I / /// / ,/ / 50 g A. OMPA Spray l ,: B. OMPA Aerosol )LO ‘ . C' : C. Systox spray l u 30 ,' l 20 4 l I. l ‘I «10 g l l l o S 10 15 20 pg 30 Number of Days Exposure To Material %An average 5% kill in check *1 .— A rigure 3Q. mf‘ectiveness of Aramite Against Mites “ Percent Control 100 ' " 80 70 60 50 A. Arsmite Wettable Powder ‘L0 30 2O 10 0 S 10 15 20 26 Number of Days Exoosure To Material *An averaqe 10; kill in check Figure MO. Effectiveness of Monsento Chemical 3897 Against Mites Percent Control 100 90 7o \ 60 A. Monsento Chemical 3997 Aerosol 'LO 30 10 0 S 10 13 ?O CS 3'1 Number of Days Exnosure To Material *5“ average 8: kill in check Figure hl. Effectiveness of TEDP Against Mites Percent Control 100 90 80 70 l 60 H ' A. TED? Aerosol 90 B. TEOP Pressure Fumigator to 30 “I 10 I 10 15 20 25 30 Number of Days Exposure To Material 4 sin average at kill in check Figure k?. Effectiveness of Certain Materials Against Slugs 3 Percent Control 100 Metaldehyde plus Calcium Arsenate Poison Bait COpper Sulrhafie, Fresh . Conrer Sulphate After One Week Chlordane Dust U OD.) ID // B/ I: / / /\'\/ -Caf”’ ,/ M/ /"“’/ / 7? 95 190 1th 168 Number of Hours Errosure To Mqterial *An average 1: kill in check VI . DI SCTTSSI ON OF RESULT S VI. DISCUSSIOK OF RESULTS The following discussion consists of two parts. In part one an attempt has been made to evaluate the effectiveness of each of the materi- als used in the different tests. Part two consists of an evaluation of the methods of application of the various materials. PAST 0V3 A. Evaluation of Materials 1. Effectiveness Against Aphids A large number of the materials tested against aphids proved very effective. The results of these tests showed either complete control, as shown in Figures 16 to 21, or complete lack of control. One formulation proved as effective against aphids as did another. Excellent results were obtained with the following materials: . . TCDP, 15% Suoke Generator TSDP, 5% Aerosol Parathion, 13% Aerosol Parathion, lSfl'flettable Powder TEPP, 10% Aerosol TEPP, 20% Emulsible Liquid Spray 4049, Emulsible Liquid Spray 4049, 25373 'A'ettable Powder 4049, 10% Aerosol Vonsanto Chemical No. 3897, 10% Aerosol Black Leaf 99', 13% Aerosol Tetra n-propyl dithiono pyrophosphate, 10% Aerosol Sodium Selenate, Applied to the Soil Potosan, Emulsible Liquid Spray Black Leaf 40', Spray “etacide, Emulsible Liquid Spray Dimethyl Paranitrophenyl thionophosphate, 10% Aerosol Black Leaf 40' plus Red Arrow Spray "onsanto Chemical No. 2413, 1 % Aerosol -91- Nonsanto Chemical V0. 876, 10% Aerosol Vonsanto Chemical No. 1049, 10% Aerosol OTLPA, Emulsible Liquid Spray OTPA, 10$ Aerosol Systox, Emulsible Liquid Spray Vice-fume, Pressure Fumigator Within a 24 hour period 90 to 100 per cent control was obtained with the following materials: Black Leaf 40', TSPP, Black Leaf 99', 4049, parathion, and TBDP. The form in which the material was used was insig- nificant and the high degree of control remained over a 30 day period. Ninety to 100 per-cent control within a 24 hour period was also ob- tained with the following materials; dimethyl paranitrophenyl thionophos- phate, Black Leaf 40' plus Red Arrow Spray, Wonsanto Chemical No. 3897, Vbnsanto Chemical No. 876, Wensanto Chemical No. 2413, and Netacide. However, the effectiveness of these materials declined rapidly after three to five days. Effective control with the systemics, Systox, C”PA and sodium selenate was not obtained until after a 25 to 30 day period. Potosan was the fast- est acting of the systemics, but the maximum control obtained with it was only 98 per cent. Tetra n-propyl dithiono pyrophosphate was quick acting and long last- ing, but the average control over the 30 day period was only 87 per cent. All other materials tested were ineffective against aphids. 2. Effectiveness afiainst adult mealy bugs The number of materials controlling adult mealy bugs was limited. EDP, parathion, TEPP, 4049 and Vonsanto Chemical No. 3897 cleared up all infestations both under laboratory and under growing conditions. Of these -92- five materials parathion and TSP? were the most efficient and the most reliable. "onsanto Chemical No. 3897 was the next best followed by TEDP and 4049. Thterials giving sporadic control included Black Leaf 99', Black Leaf 40' plus Red Arrow spray, OVPA, Systox, and Eico-Fume Pressure Fumigator. Repeated tests of these materials did not give consistent results. All other materials tested gave no control of adult mealy bugs. 3. Effectiveness against mealy bug crawlers. In general, the same materials that controlled the adults of the mealy bugs also controlled the crawlers. Paterials controlling the crawlers were: TEUP, 5% Aerosol TEDP, 15% Smoke Generator Parathion, 10$ Aerosol Parathion, 15% Wettable Powder' TBPP, 10%.Aerosol TEPP, 20% Emulsible Liquid Spray 4049, 25%‘Wettable Powder 4049, 10% Aerosol 4049, Emulsible Liquid Vensanto Chemical Yo. 3897, 10% Aerosol Systox, Emulsible Liquid Spray Systox, although not good as a control for adults did give satisfactory results when used against the crawlers. The one drawback to this material was that it could not always be relied upon. Occasionally control was not obtained when using Systox. 'Sporadic control was obtained with the following materials: Black Leaf 99', 10% Aerosol CWPA, Emulsible Liquid Spray O”PA, 10% Aerosol Nico-fume Pressure Fumigator Potosan, fimulsible Liquid Spray Black Leaf 40', Spray . Netacide, Emulsible Liquid Spray Dimethyl para nitrophenyl thionophosphate 10% Aerosol DDT, 25% wettable Powder Black Leaf 40' plus Red Arrow Spray All other materials tested were ineffective against the mealy bug crawlers. The fact that only a limited number of materials gave satis- factory control against mealy bug crawlers can be attributed to the pro— tection of 819 cottony mass in.which the crawler spends much of its time. 4. Effectiveness against slugs. The primary purpose of the tests against slugs was to find a new and efficient molluscacide. The materials used to control the slugs at the present time (copper sulfate and metaldehyde plus calcium arsenate) gave only mediocre control as shown in Figure 42. Only 50 per cent_control was obtained with a fresh solution of copper sulfate while a week-old applica- tion resulted in.almost no control. When using a poison.bait of metaldehyde and calcium.arsenate pellets it was found that approximately half of the slugs succumbed to the poison within a 72 hour period. The other half were not affected. Repeated tests using this bait gave the same results, ap- proximately half of the slugs being killed by the poison. The other half were not killed even thmigh fresh pellets were introduced onto the experi- mental flats. A five per cent chlordane dust proved very effective as a slug conp trol. Complete control resulted within 48 hours after the application of the material. Repeated tests confirmed these results. The materials tested against the slugs which did not result in con- trol were as follows: Lindane, 1% Pellets 4049, 1% Dust EPN 300, 1% Dust mn,1q€mmt Aldrin, 2%575 Dust Dieldrin, 1% Dust Parathion, 1% Dust 5. Effectiveness Against Parathion Resistant Kites 0f the various materials tested as miticides the following cleaned up infestations under laboratonv conditions: Aramite, 15% Wettable Powder DWC, Pressure Fumigator Dimite, 25% Emulsible Liquid Spray "onsanto Chemical No. 3897, 10% Aerosol K-6451, 10$ Aerosol K-645l, 50% wettable Powder F-6451, 50% wettable Powder on steam pipes 0”PA, Emulsible Liquid Spray 0“PA, 10% Aerosol Systox, Emulsible Liquid Spray TEDP, 15% Smoke Generator TEDP, 5% Aerosol The following resulted in control under growing conditions: Aramite, lSfl'Wettable Powder D"C, Pressure Fumigator "ensanto Chemical No. 3897, 10% Aerosol K-6451, 50% Wettable powder on steam pipes TEUP, 15% Smoke Generator TEDP, 5% Aerosol The Aramite and the D"C pressure fumigator were outstanding as miti- cides. Monsanto Chemical No. 3897, K-645l and TEDP also resulted in good control by keeping infestations to a minimum. There was no opportunity to test CLPA, Systox, TEDP aerosol, DEC aerosol and spray and the K-6451 aerosol and spray under actual growing conditions. However, the results of the tests under laboratory conditions indicated the possibilities of these materials for the control of the parathion resistant mites. Although consistent control was obtained with the D70 pressure fumigator the results obtained with the Dimite emulsible spray were very erratic. Early in the tests Dimite gave good control. Later when addi- tional tests were run to confirm these results the material did not give satisfactory control. However, the last of the tests run.with this material gave the results shown in Figure 36. Blauvelt (:5) tested K-6451 in the aerosol form and reported very good results. To confirm these remilts a house of approximately 10,000 cubic feet was treated with K—645l for a period of two months. Since various reports also mentioned the occurrence of plant injury when using the K-645l as an aerosol, the K-6451 was applied as a 50% wettable powder painted on.the steam.pipes. Applied in this way, the material was disf persed much more gradually than when discharged from.the aerosol, thus reducing the chances of injury. As K-6451 is slow acting, satisfactory results were not obtained until after 20 days. At this time the infesta- tion decreased sharply and additional applications kept the infestation down. None of the other materials tested were effective as miticides. 6. Effectiveness Against Adults of Soft Brown Scale The soft brown scale proved to be the most difficult pest to control in the greenhouse. 0f the forty different materials tested only three proved effective. However, the results obtained by use of these three were excellent. These materials were: .86.. K-6451, 10¢ Aerosol K-6451, 50% Wettable Powder TJDP, 5% Aerosol TEDP, 15% Smoke Generator 4049, Emulsible Liquid 4049, 257 wettable Powder 4049, 10% Aerosol F. F. Smith (22) reported that 4049 did not control the soft brown scale. However, in the tests conducted by the author 4049 25%‘wettable powder proved the most effective material. Complete control was obtained in all the laboratory tests performed and in all the tests carried out under actual growing conditions. Complete control was obtained within six days and remained as such over the 30 day period. The 4049 in the form of an emulsifiable oil or as an aerosol was not as effective as the wettable powder but resulted in a high degree of kill. Results of tests conducted with K-6451 agreed with those reported by Blauvelt ( 3 ). The K-6451 was very slow acting but a high degree of kill was obtained. Complete control was also obtained with TEDP. This material, however, was ineffective until after the second application, at which time the per cent kill increased sharply and complete control was obtained. This material was also very effective under actual growing conditions. Twp forms of this material were tested, the aerosol and the smoke generator. The degree of control obtained with each was approxi- mately the same. Other materials tested were ineffective against the adults of the soft brown scale. 7. Effectiveness Against Crawlers of the Soft Brown Scale MinuS'the protective scale of the adult, the crawlers of the soft PART TWO B. Evaluation of Wethods of Application Aerosols, sprays, pressure fumigators, wettable powders and solutions applied to steam pipes, solutions applied to the soil, and poison baits were the forms in which the various materials were used. 0f the seven different foxnn used, the sprays gave the best results with the fewest number of applications. This is shown in.the various graphs in which a material in the form of a spray is compared with the same material in the form of an aerosol or as a pressure fumigator. One application of a material in the form of a spray equalled two to three applications of an aerosol or pressure fumigator in effectiveness. In addition air currents which were a factor to be considered when applying an aerosol or pressure fumigator were not important when spraying in the greenhouse. The dis- advantages of spraying were the objectionable residue sometimes left on the leaves of plants and the amount of time and labor required. It re» qzired approximately two minutes to treat a house of 25,000 cubic feet with an aerosol, compared to fifteen to twenty minutes to spray the same house. Furthermore, the spray materials had to be mixed beforehand and the sprayer had to be checked for gas, oil and water. After spraying, the sprayer had to be cleaned. All this was time consuming. The four-pound aerosol bomb was loaded within a ten-minute period and was good for about four applications in a house of 25,000 cubic feet. Besides the calcula- tions no other preparation was necessary before applying an aerosol and no cleanup was necessary after the application of the aerosol. However, certain factors limited the application of the aerosols. Air currents in the greenhouse were particularly important. Air will remain still only when the denser portions are at the bottom.and there is a regular decrease in density towards the top. Therefore, because air expands when heating, thus diminishing in density, the warm air moves upward and the cold air moves downward to take its place. This results in a continuous air move- ment within the greenhouse, Figures 14 and 15, Page 65. Therefore, on one day under certain conditions of temperature, wind direction and wind velocity there may be a cold area in fine center of the greenhouse. 0n the next dai, under different conditions the cold spot may be in a different part of the house. When conditions such as this did arise the author found certain areas in the treated compartment apparently untouched by the aerosol while in another area control was obtained. Leaks in the greenhouse were another factor to be considered when ap- plying aerosols. The author experienced many failures when applying a particular aerosol under actual growing conditions until a broken.vent in the top of the house was noticed. Referring to Figures 14 and 15 it can be seen that the aerosol was carried up and out of the greenhouse and never fell, in any appreciable amount, upon the plants. Therefore, even applying the aerosol in very calm weather would not result in control when such an obstacle as a broken vent was present. The factor of air currents must also be considered when applying the pressure fumigator. These are applied under the same conditions that are required for the aerosols and are about equal in effectiveness. In addi- tion they are more easily applied, merely requiring ignition of the con- tents of the pressure can. The one drawback experienced by the author 190 when using the pressure fumigator was in the failure of certain pressure cans to ignite. This is important as a house of 25,000 cubic feet re- quired from.two to six pressure cans, and the procedure followed required the igniting of one fumigator, stepping back to the next can, igniting it, etc. In addition the cans must be placed at different points about the house to insure even distribution of the material. Therefore, the failure of just one can to ignite will endanger the person or persons making the application as the cans upon ignition.will begin.to discharge their con- tents into the house while the operator is still working with the bad pressure can. If ignition could be depended upon for each pressure funn- gator, application would merely involve placing the required number of cans about the house, igniting them, and vacating the house. No special emiipment such as gas mask or special clothing would be necessary. Evaporating material from.the steam pipes had the possible advantage of less injury to the plants because of the slower distribution of the material into the house. However, in tests conducted by the author the degree of kill was not as high as that of aerosols, pressure fumigators or sprays. Poison baits in the form of pellets, dusts and solutions of materials painted on flats and flower pots were used in tests conducted against slugs. In regard to the baits it was found that approximately one-half of the slugs ate the pellets and died from.the effects while the other half either refused the bait or else were not effected by the poison. The poison baits were applied by scattering the pellets among the pots and flats. Dusts applied among pots and flats on the benches have the disadvantage of being very noticeable and for this reason solutions of the materials are preferred. -101- The materials in the form of solutions were painted on the flats, pots and benches with an ordinarr paint brush. The materials in solution form.can be applied anywhere in the greenhouse without the presence of an objectionable residue spoiling the appearance of the greenhouse. -102- VII . SW”? ’ARY VI I . SHERRY Approximately forty different materials were tested in the laboratory to determine their value as insecticides, miticides and molluscacides. The materials showing pronnse under laboratory conditions were then tested under actual growing conditions against natural infestations of the vari- ous pests. In addition different forms of the materials were used in an attempt to determine which, if any, was the best method of application. A number of materials were found that would control aphids. Foremost among these were parathion and TEPP. The form in which the insecticide was applied made no difference in the degree of kill of this pest. The most difficult pest to control in the greenhouse was the adult soft brown scale. Only three of the materials out of the forty tested proved effective for hue control of this pest. These three were 4049, K-6451 and TEUP. When applied as a spray, three applications of these materials at weekly intervals cleared up infestations under growing condi- tions for periods ranging from 30 to 50 days. When applied as an aerosol twice as many applications were needet. Without the protective scale of the adult the crawlers of the soft brown scale were more easily controlled. In addition to the materials which controlled the adult the crawlers were also susceptible to parathion. TEPP, OWPA, Systox and DDT. However, the control obtained was not always complete, as crawlers were continually emerging from under the shell of the adult after the effectiveness of the material had decreased or had disappeared entirely. -103- The adult mealy bugs were almost as difficult to control as were the adults of the soft brown scale. TEDP, parathion, TEPP, 4049 and Vonsanto Chemical No. 3897 cleared up infestations under laboratory and growing conditions. Parathion and TEPP were the most efficient. The crawlers of the mealy bugS'were controlled with the same materials that controlled the adults. In addition sporadic control was obtained with Black Leaf 99', OVPA, Nico-Fume Pressure Fumigators, Potosan, Black Leaf 40', hetacide, dinmthyl paranitrophenyl thionophosphate, DDT and Black Leaf 40' plus Red Arrow Spray. The cottony, waxy eff sac laid down by the adult female appeared to protect the young from many of file insecti- cides and is the possible explanation of the erratic control as the young remain in this sac for a short time after hatching from the eggs. When repeated applications were made the crawlers could be cleaned up eventually. But when applying the material for three weeks at weekly intervals the crawler population actually increased. Only the TEDP, parathion, TEPP, 4049 and Monsanto Chemical Ho. 3897 gave satisfactory results. Under laboratory conditions the parathion-resistant mites succumbed to the following materials: Aramite, DTTC, Tfonsanto Chemical Ho. 3897, K-6451, OVPA, Systox and TEDP. Under growing conditions only Aramite, D70, “onsanto Chemical No. 3897, K-6451, and TEUP gave control. Although the organic phosphates were generally ineffective against the parathion resistant mites, TflDP (tetra ethyl dithio pyrophosphate) with the added sulfur in the phOSphate group gave kills ranging up to 95 per cent. The Aramite wettable powder and the DHC pressure fumigator were outstanding as miticides, clearing up infestations when all other materials failed. The K-6451, although slow in action could, when combined ~104- with TEDP, be very effective. When testing K-6451 and TED? together two applications of TED? were applied at three-day intervals followed three days later by an application of the K-6451. The TEDP being quick acting and the K-6451 being long acting reailted in good control. Ten materials were tested to determine their value as molluscacides. Of these only chlordane was effective. Complete control resulted within 48 hours. Twp materials were tried in the fonn of poison pellets. They were lindane and a combination of metaldehyde and calcium arsenate. The lindane pellets were totally ineffective while the metaldehyde-calcium arsenate pellets were only 50 to 60 per cent effective. When introduced onto a flat containing slugs approximately half of the slugs ate the poison bait and died and the other half rejected the bait entirely even though fresh pellets were placed on the flat. The method of applying the material was considered to be as important as the material being applied and consequently each method of application was thoroughly investigated. Lhterials were used in the form of wettable powder and emulsible oil sprays, as aerosols, as pressure fumigators, as wettable powders evaporated from steam.pipes, as solutions poured on the soil containing infested plants, as solutions painted on pots and flats containing infested plants, as poison baits and as dusts. 'Wettable powder sprays proved to be the most effective method of application. The aerosol was also effective but required twice as many applications to obtain the same degree of control. Materials applied from pressure fumigators were about equal to those applied as aerosols. However, the results of some tests indicated that the heat generated by the pressure furngator, may decrease the effectiveness of the material -105- to an appreciable extent. Dusts were an effective means of control but the time involved in applying dusts was too great and the unsightly residues left by the powders were objectionable. The materials applied as solutions painted on pots and flats were'very effective and, depending upon the material, remained effective for long periods of time. Solutions poured on the soil were taken up very slowly by the plants and as a result no control was obtained when using materials in this form. The systemics were much more effective when sprayed on the plants. Pests on woody plants, such as roses, were not affected by the systemics. When the material was evaporated from steam pipes good control was obtained al- though not as good as when the same material was applied as an aerosol. The possible advantage of evaporation of material from steam pipes lies in the fact that a slower distribution, which occurs when the material is evaporated from.steam pipes, may result in less injury to the plants. Regardless of the method of application certain factors were en- countered which affected the control. Higher kills were obtained on thin- ly foilated plants than on those with denser foilage. The condition of - the plant was important. Greater kills were obtained on plants in a 'weakened condition than on those in a more vigorous condition. The host plant was important. Mites were more easily controlled on bean plants than when the same mites were transferred to rose plants and tested with the same material. Temperature was very important. 'When it was maintained at 78 degrees Fahrenheit 100 per cent control was possible, but when the temperature was allowed to drop to 68 degrees Fahrenheit approximately 60 per cent control resulted. Air currents were also important when applying -lO6- aerosols. If the aerosols wereaapplied on windy days an uneven distribu- tion of kill resulted in the house. If the house was not airtight con- trol was not possible. LITjfiRATTTRE CIT ED 4. 5. 6. 7. 9. 10. ll. 12. LITERATURE CITED Armstrong, T. 1950 A Laboratory Study on the Toxicity of Para-Chlorophenyl Para-Chlorobenzenesulfonate to ”ites. Dgwn to Earth, Vol. 6 No. 1, 6-7. Babers, F. H. 1949 Development of Insect Resistance to Insecticides. U.S.D.A. Publication 3-776. Blauvelt, W. E. and Hathaway, ”N. B. 1950 Y—6451 Aerosol For Greenhouse Vite Control. Down to Earth, Vol. 5 No. 4, 2-4. Blauvelt, W. E. 1947 Azobenzene Developments. New'York State Flower Growers Bulletin 19. Bussart, J. E. and Schor, A. 1950 Chlordane, Report of Velsicol Corporation. Conmtock, J. H. 1947 An Introduction to Entomology. Comstock Publishing Company, Inc., Ithaca, New York. 413-428, 440-459. EngliSh, Lo Lo 1950 Azobenzene as an Effective Supplement in Organic Phosphate Aerosols for Control of the Two-Spotted Spider Mite. Jour. Econ. Ent., 43: 858-843. Flanders, S. E. 1951 Citnis ”ealybug Parasites. California Agriculture. V01. 5 No. 7, 11—12. Frear, D. 5. H. 1948 Chemistry of Insecticides, Fungicides, and Herbicides. D. Van.Nostrand Company, Inc., New York, NeW'York. German, Philip. 1950 Parathion Resistant Red Spiders. Jour. Econ. Ent., ' 43: 53-56. Gray, H. E. 1947 The Cause of Cold Spots in the Greenhouse. New York State Flower Growers Bulletin 26. 2-8. Hamilton, C. C. 1947 Azobenzene Dusts to Control Red Spider on Some Green- house Plants. Jour. Econ. Ent., 40: 733—735. -108- 13. 14. 15. 16. 17. 18. 19. 20. 21. 23. 24. Hoffman, J. R. 1948 Hexaethyl Tetraphosphate and Tetraethyl Pyrophosphate as Aerosols against the Two-Spotted Mite. Jour. 3con. E23., 41: 356-362. Vetcalf, C. L. and Flint, W. P. 1939 Destructive and Useful Insects. HcGraw-Zill Book Company, Inc., New York, New York, 727-762. Neiswander, C. R., Rodriguez, J. C. and Neiswander, R. B. 1950 Natural and Induced Varations in Two-Spotted Spider Vite Populations. Jour. Econ. Ent., 43: 633-636. Pritchard, E. A., and Beer, R. E. 1949 Parathion for Control of Pests of Ornamental and Flower- ing Plants. Jour. Econ. Ent., 42: 372-379. Richards, G. A. 1948 Chemical Control. Agricultural Chemicals, Vol. 3 No. 8, 33-34, 77. Ripper, V‘Io E0 1950 The Outlook For Systemic Insecticides. Down to Earth, V01. 6 NO. 3, 13-160 Shepard, H. H. 1939 The Chemistry and Toxicology of Insecticides. Burgess Publishing Co., ”innespolis, ”innesota. 28-109, 157-243, 307-352. Smith, F. P., Fulton, R. A. and Brierly, P. 1947 Aerosols in Greenhouses. Agricultural Chemicals, V01. 2 NO. 12, 28-31, 610 Smith, F. F., Fulton, l. A. and Brierly, P. 1948 Aerosols in Greenhouses. Agricultural Chemicals, V’Olo 3 NO. 1, 37-39, 770 P. 1951 Proceedinrs Sixth Annual Ieeting North Central States Branch Association of Economic Entomologists. 110-115. Smith, F. F. and Fulton, R. A. 19 O Tetraethyl Dithiopyrophosphate Aerosols For the Control of Greenhouse Insects. U.S.D.A. Publication E-803. Smith, P. F. and Fulton, R. A. 1951 Two-Spotted Spider Vite Resistant to Aerosols. Jour. Econ. Ent., 44: 229-233. -109- 25. Smith, F. F., Fulton, R. A. and Hall, S. A. 1950 Toxicity of Organic Phosphates to the Two-Spotted Spider idte and the Foxglove Aphid. Jour. Econ. Ent., 43: 627-632. 26. Thayer, C. L. and others. 1946 Department of Florieilture Bulletin.No. 436. “ass. Agr. Exp. Sta. (Rep. 1945-46), 44-45. 27. wallace, P. P. 1951 Octamethylpyrophosphoramide. Jour. Econ. Ent., 44: 224-228. 28. White 1947 Proceedings American Society Horticultural Science. 47: 451-462. 29. Yeomans, A. H., Rogers, E. E. and Bell, W. H. 1949 Deposition of Aerosol Particles. Jour. Econ. Ent., 42:591-596. 30. 1951 Metacide. Down to Earth, Vol. 6 No. 4. 31. 1950 Report of Pittsburgh Agricultural Company on Wetacide. 32. 1950 Report of Pittsburgh Agricultural Company on Potosan. 33. 1950 Report of Pittsburgh Agricultural Company on Systox. 34. 1950 Report of Geary Chemical Corporation on Systox. 35. 1951 General Information on Experimental Use of Dieldrin. Julius Hyman and Co. Cir. SOO-A. 36. 1949 Entomological Report on Aldrin. Julius Hyman and Co. 37. 1950 Entomological Report on Aldrin. Julius Hyman and Co. 38. 1950 A Manual of Technical Data on EPN 300 Insecticide. E. I. duPont de I‘Eemours Co. -110- Mr 14 '9 61A ROOM USE ONLY 42% '53 l \M I .. our-n... .f‘.‘ A TY “"TITI'ITWLEJIMHfiilujfflinmmfljflilmfl'“