L:r^ * RY STATE PLANT BOARD February 1946 E-682 United States Department of Agriculture Agricultural Research Administration Bureau of Entomology and Plant Quarantine INSECTICIDAL TESTS OF SOME MATERIALS ON THE MEXICAN BEAN BEETLE By E. R. McGovran and P. G. Piquett Division of Control Investigations The Mexican bean beetle ( Epilachna varivestis Muls.) has been used as a test insect to determine whether materials found toxic to other insects were toxic to this species. The materials include a large number of synthetic organic compounds, various formulations containing DDT, nicotine preparations, and plant materials. The tests were made when insects and bean foliage were available in the field. Technique The spray-tower technique 1/ was used in making these tests. In some of the tests adult beetles were used, but in most of them late third-instar or early f ourth-instar larvae were the test insects. Observations were made on feeding, but since in most cases moderate or heavy feeding was accompanied by low mortality no record of the feeding is included in this report. In most instances 4 tests with 10 insects each were made on each material. Acacia (gum arabic) at 1:1000 was used as the wetting agent in most of the sprays. Mortality counts were generally made at the end of 6 days. After the insects had been in a cage with a treated leaf for 3 days, the leaf was removed and an untreated leaf was put in its place. This gave an • opportunity for insects that had been slightly poisoned but not .killed by the treatment to recover on the untreated foliage. This change of foliage to some degree simulated conditions in the field, where a few days after treatment insects can usually find untreated bean foliage upon which to feed. Foliage-injury tests were made on potted bean plants in the greenhouse* McGovran, E. R. , and Mayer, E. L. A laboratory apparatus and procedure for testing aqueous spray suspensions as insecticides. U.S. Bur. Eat. and Plant Quar. ET-208, 7 pp. 1943. [processed.] Derris Standard Since derris, when available, ia widely used for the control of the Mexican bean beetle, it waa chosen as a basis for evaluating the various materials* Two samples of derris were used, one containing 4*9 percent of rot en one and the other 4.8 percent. The first sample was used on adults and the second on larvae. When derris was used at the rate of 1 pound per 100 gallons, the average kill of adults was 91 percent and of larvae from. 34- to 62 percent (table 2), In tests en larvae with 4 pounds of derris per 100 gallons the kill was somewhat higher but usually not 100 percent. Manr adults and larvae that had not fed appreciably on treated foliage, and appeared torpid at the end of 3 days, revived and fed extensively on the untreated foliage when it was put in the cage* Synthetic Materials 2/ The results with the more toxic synthetic organic compounds tested ar* glv. .ai table 1* Of these, acetone se.^.-iarbazone and 4, 6-dinitro-oreresyl acetate were the most toxic, r ninoacetanilide, cyclohexanone semicarbazone, dinitro-o-cresyl methyl ether, and ethyl methyl ketone semicarbazone also showed high toxicity. All these compounds except p-aminoacetanilide caused foliage injury. 2/ Most of the synthetic materials tested were furnished by the Division of Insecticide Investigations. Table 1. — Synthetic materials showing considerable insecticidal action On the Mexidan bean beetle Material 1/ Stage of insect Concentration Mortality 2/ Percent Percent Acetone semicarbazone A 1 .5 ♦25 .125 85 (m-se) 85 80 U6 Acetone semicarbazone $0 S lime 5C Irk 1 l00*(t-sl) p-Aminoacetanilide A .125 .25 .5 l 7 50 78 (n) 91 m-Aminoacetanilide hydrochloride A l 78 p-Aminoazobenzene hydrochloride A .5 l 65 69 p-Bromo-N-ethylbenzenesulfonamide L-k l 52* N-Butyl-m-nitrobenzamide L-3 l 35* N-se c -Butyl-n-nitrobenzaadde L-3 ) .Alt 2- ( p-Chlorophenyl ) -2-ph*nyl- ±,•1 , 1-trichloroethane L-3 1 57* Cyclohexanpne semicarbazone L-U .5 l 85* 91*(sl-se) Cyclopentanone semicarbazone Irk. .5 l U9* 60* alpha , be ta-Dibromo-be ta-n i t r o- •thylbenaene Irh l U6» Table 1. — (Continued) Material 1/ Stage of insect Concentration Mortality 2/ Percent Percent N , N-Die thylc innamide 1 6o* l*,6-Dinitro-o-cresyl acetate A .125 .25 .5 l 80 (si) 9h 88 92 h , 6-Dinitr o~o-cresyl ethyl ether L-3 l 57* Dinitro-=o~cresyl methyl ether A .25 1 55 93 (sl-m) Diphenylene oxide A 1 51 Diphenylene oxide 50, magnesium carbonate 50 A 1 66 Diphenylene oxide 20, steariG acid 20, talc 60 A 1 69 Diphenylene oxide 50> zinc stearate 50 A 1 52 Diphcmylene oxide 50, talc 50 A 1 2 33 90 N ,N-In\ propyl -m-nitrobenzamide L-3 1 65* gamma , gtama-Dipyr idyl A 1 72* Ethyl methyl ketone semicarbazone Irk .5 l 95* 85* (se) 2-Furaldehyde semicarbazone L-ii l 55* Table 1. — (Continued) Material 1/ Stage of insect Concentration Mortality 2/ Percent Percent Isovaleryl-1 , 3-indan di one L 1 85* Pen ca chl orodi hy dr oxyt riphenyl- rnethane sulfonic acid A 1 81 Phenazine A 1 2 81* 71* Phenothiazine A 1 94 Phenoxathiin A 1 61* p-Phenylaz oaniline A .125 .25 1 14 78 p-Phenylenediamine A .125 .25 1 13 32 67 £-Phenylenedianine dihydrochloride A 1 74 beta-Tetrahydronaphthoylaceto— nitrile. 50, oyrophyllite 50 L-4. 2 55* l-Trichloro-2-2 bis(p-methoxy- phenyl) ethane L 1 65* 2 , U- ( Tri chlor omet hyl ) -sym-trioxane L-3 1 47* 2-Thi o c oumar in A .125 .25 7 51 Xanthydrol A .125 .25 1 13 20 68 - 6 - Table 1. — ( Concluded) Material 1/ Stage of Insect Concentration Mortality gj Pfrrgeat Percent Derris (roteaone 4.9) .125 91* Derrie (roteaone 4.8) L-3 and L-4 .126 46* (1942) 62* (1943) 34* (1944) Xj Numbers in this column refer to percent*. Zj Starred items indicate 6- day mortality, una tarred items 3-day mortality. Letters in parentheses indicate foliage injury as follows: n, none; t, trace; si, slight; a ( moderate; se, severe. The following synthetic materials showed some toxicity when used at eight times the concentration of derris, but never more than equaled the derris standard in kill? E-Bromo-N, H-dimethylbenz ene sulfonamide H-Bromo-N-i sobutylbenz ene sulfonamide E-Broao -$-p ropy lb en z ene sulfonamide 4- Camphor oxime k-Ch.loro-N~-propylb en zene sulfonamide Diazoamlno bens ene 2,4-Dim*thyl-3-pentanone semicarbazone 4,6-Dinitro-a-cresyl laurate 4,6-Dinitro-a-cresyl myri state 4, 6-Dinitro-pj-cresyl propionate 2, 4-Dini trophenyl propionate Di sodium ethyl enebisdithio carbamate Ithylidenebisbensamide 2- Fur ana cry lam id* 1-Benzoyl thiourea - 7 - alpha, alpha, alpha, alpha' , alpha 1 , alpha* -Hexachloro-jt-xylene 2' -Hydroxy-2, 4,4,4', 7-pentane thylf lavan N-I so butyl-a-ni trobenzami do 5-( p-Methoxybenzylidene) -2-thio-4- thiazolidons p-Nitroacetaailide 4-Phenyl thio semi carbazide o_-Phthalonitrile 4, 4' , 4 " -Triaminotriphenylcarbinel ( jL-rosaniline base) alpha, alpha, beta-Trichlorobutyraaide Veratrlne Xanthene The following synthetic materials showed little if any toxicity to the Mexican bean beetle when tested at a strength of 1 percent: Mfttfrtftls. Tested, at team Materials Tested as Pasts 5-Benzyli&ene-2-thio-4-.thiazolidone 2-Chlorofluoreae E.fc'-Diehlorophenyl sulfone Diisophorone 1 , 4-Dini tro sopiperazine 1 , 4-Diphenyl s eai oarbazide 2-Fluo ry lam ins alpha , alpha , alpha , alpha 1 * alpha ' , alpha' -Hex&chlore-o-xylene 4-( a-Methyl-alpha- this toluyl) - morpholine N-Me thyl-n.~ni troben z aaide Tetrachloroquinone 4-( alpha- Thiotoluyl) morphollne 1-Tri chloro-2, 2-bie( £-broaophenyl) - ethane N-Acstyl-alpha-naphthylaains H-Acetyl-beta-naphthylaaiae Allyl thiourea 3- Anl 1 inopheno thiazlne Asebenzene Asoxybenzene Benzalazine 2-Chlo roacr idoae Copper sulfoleoarsenite Dichloramine-T £,£.' -Dif luorodiphenyl Bis( Srdlaethylaainophenyl) sulfide 4- Hydroxyacridone Nitroguanidine H-B-Si trophenyl suif anyl) acetanilide Piperonal exiae, "anti" fera Piperoaal oxiat, - syn" form DDT Sprays The results of tests with Tarious sprays containing DDT ( 1- trichloro-2,2-bis(a-chlerophenyl) ethane) are given ia table 2. When used alone DDT was not highly toxio to Mexican bean beetle larra«. The addition of sulfonated castor oil to the spray greatly increased its toxicity. The nixtures were prepared by dissolving - 8 - the DDT in acetone and then adding bhe sulfonated castor oil. Calcium cyanamide combined with DDT and sulfonated castor oil killed all the larvae, but calcium cyanamide alone caused appreciable mortality* Table- 2. — Toxicity of variocc sprays containing DDT bo the Lexican bean beetle Formulation DDT concentration in spray l.iortality in 6 days porc^nt Percent DDT (technical) 1.0 16 DDT 1C percent in pyrophyllite 35 DDT 10 gm«, sulfonated castor oil 10 ml. 3 acetone 60 ml. : ho addp<) ingredient Plus calcium carbonate 5 C 171 * Plus calcium cyanainide 5 grc« Plus calcium sulfate 5 .5 95 95 100 95 DDT 5 ot., sulfonated castor oil 10 ml., acetone G5 ml. : ".'o added ingredient Pius ammonium chloride 5 rn. Plus ammonium hydroxide 5 ml, i^lus ammonium sulfate 5 [p-» 65 57 55 • 70 "Jaloium cyanamide 1.0 1/ Derris standard 0.125 y 3h 1/ Percent of material indicated. - 9 - Nicotine Preparations 3/ A number of preparations containing nicotine were tested against Mexican bean beetle larvae. Nicotine refers to the uncombined alkaloid often referred to as free nicotine. Mixtures with nicotine contained 10 gm. of the compound to U gnu of nicotine. Of these, o-nitrodiphenyl mixed with nicotine gave the highest mortality. This preparation, when used at about 2$ times the concentration of derris (I4.8 percent rotenone), caused 88 percent mortality as com- pared with 3k percent for the derris standard. A 5-percent solution of kO percent nicotine sulfate was slightly more toxic than 1 pound of derris per 100 gallons of spray. Nicotine was somewhat less effective under the conditions of these tests. The following preparations showed little or no toxicity to the larvae when used at many times the concentration of derris: Benzyl nicotinium stearate Butyl carbitol plus nicotine Butyl ether of ethylene glycol (Butyl Cellosolve) plus nicotine Cupric mononicotinammino oleate Cupric nicotinammino hexoate Cupric nicotinammino compounds of coconut oil fatty acids p,p-Dichlorodiphenyl sulfide plus nicotine Dioctyl sodium sulfosuccinate (Aerosol OT) plus nicotine Ethyl ether of ethylene glycol plus nicotine (Cellosolve) Glycerol plus kO percent nicotine sulfate Methyl carbitol plus nicotine Molasses plus UO percent nicotine sulfate Sodium salt of sulfonated ethyl oleate (Artie Syntex) plus nicotine 3/ Most of the nicotine preparations tested were supplied by the Eastern Regional Research Laboratory, Bureau of Agricultural and Industrial Chemistry. Plant Sample A. sample of plant material that was tested, Humulus lupulus, showed only very slight toxicity to Mexican bean beetle larvae. Summary Results are given of laboratory te-sts of the insecticidal action of 9h synthetic organic compounds, 8 DDT and 13 nicotine combinations, and 1 plant material, with the Mexican bean beetle ( Epiiachnav . varivestis Muls.) as the test insect. Acetone semicarbazone and U,6-dinitro-o-cresyl acetate were highly toxic to the insects but caused injury to bean foliage. DDT combined with sulfonated castor oil was more toxic to Mexican bean beetle larvae than DDT alone. UNIVERSITY OF FLORIDA 3 1262 09238 7595 1