;ARY April mOAR° B-7" United States Department of Agriculture Agricultural Researoh Administration Bureau of Entomology and Plant Quarantine TESTS OF CERTAIN SYNTHETIC ORGANIC COMPOUNDS AGAINST THE TWO-SPOTTED AND RELATED MITES A. P. Yerington, Division of Control Investigations, . and S. I. Gertler, Division of Insecticide Investigations^/ At the insecticide-testing laboratory of this Bureau at Anaheim, Calif*, all compounds that had shown promise against any speoles of in- sects in previous screening teBts were subjected to further tests to de- termine their value as miticides. The mites used in these tests were the two- spotted mite (Tetranychus biaaoulatus Harvey) and Tetranyohus spp. They were collected from populations occurring naturally on oastor bean and snap bean in the vicinity of Anaheim. Infested bean leaves as needed were taken to the laboratory, where they were kept succulent by placing their stems in 125-ml. flasks filled with water. The top surface of each leaf was brushed free of mites, so that populations to be dusted were concentrated only on the lower surface. A dusting tower was used as described by Swingle, Phillips, and Gahan, 2/ The procedure was modified to permit treatment of entire leaf and stem. ,JVith this apparatus between 200 and 300 micrograms of material were de- posited per square centimeter, the actual amount being determined by weighing an aluminum plate dusted at the same time. The dusted leaf (stem in flask of water) was oonfined in a battery jar, and mortality counts of the nymphs and adults were made at the end of 3 days. For the ovicide tests all of the leaf was removed except an area containing a fairly large number of eggs, which was subjeoted to an air blast that removed most of the mites. Any remaining young and adult mites were removed under a binoc- ular microsoope with a disaooting needle0 The leaf section containing the eggs was then dusted, placed in a battery jar, and kept in a thermostat- ically controlled box at a constant temperature of 85°F. and a relative humidity of 40 to 50 percent. A 3-day test period was allowed prior to making mortality oounts. Of 1,370 synthetic organic oompounds tested previously at this labora- tory 126 were found to be toxio to one or more insects. Of these compounds 85 were tested as dusts against young and adult mites at a concentration of l/ The writers are indebted to G. T. Bottger, under whose supervision this work was conduoted. 2/ Swingle, M. C, Phillips, A. M., and Gahan, J. B. Laboratory testing of natural and synthetic organic substances as insecticides. Jour. Econ. Ent. 34: 95-99. 1941. - 2 - 25 percent in pyrophyllite* Two standards were used throughout the testa, benzene hexachloride (5-percent gamma isomer) and bis^p-chlorophenoxy)- methano (1-peroent) • Treatments with 22 of the compounds oaused mortali- ties of 75 percent or more* Compounds nontoxio to mites in these tests were as follows* pj-Aminoazobenzene hydrochloride 2,2-Di-p-anisyl-l, 1 , 1-trichloro- ethane Arsenic ethyl xanthate l-Benzoyl-2-phenylhydrazine 4-3 romoacetophenone p-Bromobenzene sulfonamide p-B romob enzonitrile 6-Ethyl-l-phenyl semioxamazlde alpha, alpha-Hexaohloro-o-xylene alpha, alpha-Hexachloro-m-xylene Bis(2-hydroxy-3,5,6-trichlorophenyl)- me thane Indole £-Iodoaniline 1-1 s ocap royl-2-phenylhydrazine p-Bromo-N-isobutylbenzenesulfonamide N-Isopropyl-m-nitrobenzamide p-Bromo-N-propylbenzene sulfonamide 4-(p-Methyl-alpha-thiotoluyl) moj 2,2-Bis(£-br«aophenyl)l,l,l-trichloro- pholine ethane N-sec-Butyl-m-nit robenzamide 1-1 sobutyryl-2-phenylhydrazine jo-Chloroaoetanilide p-Chlo robenzenesulf onamide 5-(4-Chlorobenzylidene)-2-thio-4- thiazolidone Chlorobis(p-chlorophenyl)methane Chloromethyl phenyl sulfone be ta-C hlo ronaphthalene 2-Chloro-6-nitro toluene 4-C hi o ro- 2-ni t ro toluene 2-Methylcyclohexanone semicarbazone 4-liethyloyclohexanone semi oarbazone Methyl 2-naphthyl ether 5-Methyl-l-phenylsemioxamazide p-Nit roaoetanilide T-(m-Ni trobeazoyl)-2-phenylhydrazine l-(p~Nitrobenzoyl)-2-phenylhydrazine jg-Nitro phenyl ester of aoetio aoid alpha, alpha, alpha, 2 ,4-Pentachlo ro - toluene Pentaerythrityl bromide Phenazine 2,2-Bis(£-ohloropheayl)l,l-dichloro- l-Phenyl-2-phenylsulfonylhydrazine ethane Copper sulfoleoarsenite Cyolopentanone semicarbazone 1, 4-D i ch 1 oro-2-nit rob en zene 3 , 4-Di chl o ro-N-met hylbenzami de N, N-D ii sop ropyl-p-nit robenzamide 5 , 5-Dimethylacridan D ime thylglyoxime 2,4-Dimethyl-2-pentanone semicar- bazone 4,6-Dinitro^a-oresol methyl ether 1,4-Dinitrosopiperazine 1,4-Diphenylsemioarbazide l-Phenyl-l,2-propanedione-2-monoxime 1-Phenylsemioxanazide 1-Phenyl- 2- (p-t o ly sul f onyl ) hydraz ine Phthalonitrile 4- ( alpha-Thiotoluyl)mo rpholine l-Triohloro~2,2-bis(5-chloro-2-hydroxy- phenyl) ethane l-Trichloro-2,2-bis(p-chloropheayl)- e thane l-Trichloro-2,2-bis(3,5-diohloro-2- hy d roxyphe nyl ) ethane 2,4-Tri Ghloromethyl-_s-trioxane Zinc mercury thiocyanate The 22 ,oxio compounds were then tested as ovicides* Compounds that were effective as ovicides or miticides at the 25*percent concentration were then tested at a 3-percent concentration against nymphs and adults, and also against the eggs* Nine oompounds oaused over 75 percent mortality in one or both cases* Compounds nontoxio to mites in all stages at this concentration were as follows a - s • 3-Aminod iben z ofuran j^Bromo-N-ethyl benzene sulfonamide Centralite 1- ^£-C hlo robeai oyl ) pipe ridtae Chloromethyl 4-chlorophenyl sulfone alpha , beta-D ib romo-beta-ait ro ethylbenze xe 2-(Diethylamino)ethyl p enta oh loro phenyl ether N,N-Diisopropyl-m-nitrobenxamide 9-Fluorenoae alpha#alpha* -Hexachloro-£-xylene N-Nit r© sodi phenylamine alpha-Thlocyanoacetophenone alpha, alpha. , beta-Tri chl o robutyr amide The nine compounds that were found to be effeotiT© as 3-peroent dusts were further tested at 1-percent strength, which is the cenoemtra- tiom recoamended for most mitioides now in oommeroial use* Only one compound, the 2-ohloroethyl ester of p-nitrobenxeic aoid, failed to show toxicity at 1 percent. Results of the teste with the ether eight cos- pounds are presented in table 1* Green foliage of five or more kinds of plants was treated with miticidal compounds to determine whether they would injure leaf tissue. The materials were applied as sprays at one or more concentrations. The results of these phototoxicity tests are presented in table 2. Of the eight compounds tested, only three— 4,6 dinitro-o-cresyl ethyl ether, isopropyl ester of ]>-nitrobenaolc acid, and 2,4-dinitrophenyl ester of propionic acid — caused no foliage injury. Two other compounds, azo- benzene and benzylphenylnitrosoamine, caused slight foliage injury. - 4 - Table 1« - Mortality of various stages of mites oaused by oompouuds used as 1-percent dusts Nymphs aad adults Eggs Compound Deposit per square centimeter Mortality ia 3 days Deposit per square c entimeter Mortality la 3 day 8 Micrograms Percent Micrograms Percoat 2, 4-Dinit ro phenol 265 100 265 100 4, 6-Diaitro-o-cresol 200 100 200 100 Propionio aoid, 2,4-dinitro- phenyl ester 200 100 230 100 Propionic acid, 4,6-dinitro- o-tolyl ester 280 97 310 100 Azobenzene 215 95 250 100 Benzylphenylnitr© soamiae 215 97 320 95 4,6-Dinitro-o-cresyl ethyl ether 200 90 200 77 jg-Nitrobenzoic acid, isopropyl ester 215 82 230 0 bis^p-Chlorophenoxy)aethaae l/ 236 Benzeae hexachloride (gamma isomer 5$>) l/ 216 48 95 270 186 88 66 l/ Used as a standard, average of 3 tests* - 6 - 0 c -P 1 3 P «H •P O © 0 o -p o O o a ■P a J? 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