LIBRARY March 1949 E-770 United States Department of Agriculture Agricultural Research Administration Bureau of Entomology and Plant Quarantine LABORATORY TESTS OF NEW COMPOUNDS AS INSECTICIDES AGAINST THE SWEETPOTATO WEEVIL By P. K. Harrison, Division of Truck Crop and Garden Insect Investigations -=/ During the years 1945, 1946, and 1947, compounds that had shown promise against other species of insects were used in poisoned baits and on sweetpotato plants in the laboratory at Baton Rouge, La., against the adult of the sweetpotato weevil, Cylas formicarius el egantulus (Summers). The test insects were reared in screen-wire cages approximately 14 by 14 by 16 inches, either in a greenhouse or in an open insectary according to the location of the tests to be conducted. All bait tests were replicated as many as four times, and some were replicated five times. The tests on the plants were replicated a minimum of four times, except a few in which the supply of chemicals was sufficient for only two or three replications. In the poisoned-bait tests ground sweetpotato was used as the carrier and was mixed with the insecticides at the ratio of 40 parts to 1 part by weight of an insecticide, regardless of the concentration or dilution in which it was received. In each cage for each replication 3| grams of the poisoned bait and 10 weevils were used. The cages used in the bait test were constructed of 18-mesh wire and were approximately 10 inches in diameter and 9 inches high. The open end of each cage was embedded in sand on a bench. Daily observations were made for 7 days, and the mor- talities recorded. The materials tested and the strengths before mixing with ground sweetpotato, together with the weevil mortalities are tab- ulated below. Percent Compound Strength and diluent mortality Acetanilide, a,a,«.,2,5-pentachloro-, Undiluted 10 Acetone semicarbazone 25%, pyrophyllite 70 Acetophenone, p-chloro-, semicarbazone do 30 1/ In cooperation with the Louisiana Agricultural Experiment Station and the Louisiana State Department of Agriculture and Immigration. -2- Compounds Aniline, p-phenylazo-, Benzamide, N-isopropyl-, Benzamide, N,N-diisopropyl Benzamide, N-(l-methylamyl)-, Benzamide, N-sec-butyl-, o-Benzanisidide Benzene, diazoamino-, Benzene hexachloride (technical) Chlordane Chlorinated biphenyl Chlorinated camphene Ethane, l,l-dichloro-2,2-bis- (p- chlorophenyl) - , Ethane, l,l,l-trichloro-2,2-bis - (p - chlorophenyl) - , Ethane, l,l,l-trichloro-2- (p- chlorophenyl) -2 -phenyl-, Ethane, l,l,l-trichloro-2,2-bis- (p -methoxyphenyl) - , Ether, 4,6-dinitro-m-tolyl methyl, Fluorene, 2-acetamido-, Fluorene, 2-chloro-, Hexaethyl tetraphosphate Hydrazine, 1 -benzoyl- 2-phenyl-, Hydrazine, 1-isobutyryl- 2 -phenyl-, Naphthenic acid, butyl ester, Paris green Phenazine Phenol, 2,2 '-(2-chloroethylidene)bis - (4-chloro-, Phenol, 2,4-dinitro-, Phenol, hexachloro-, Phenol, 2,2'-methylenebis(4-chloro-, Phenol, 2,2'-(2,2,2-trichloro- ethylidene)bis(4,6-dichloro- , p - Phenylenediamine Percent Strength and diluent mortality 25%, pyrophyllite 18 Undiluted 94 do. 78 do. 74 do. 74 do. 70 25%, pyrophyllite 48 5.75% gamma, pyrophyllite 63 50%, diluent unknown 90 Undiluted 76 48% emulsion 88 Undiluted 54 50%, diluent unknown 48 Undiluted 64 2.6% in benzene 88 3.0% in benzene 74 48%, diluent unknown 80 3.0%, pyrophyllite 62 Undiluted 35 do. 22 do. 22 do. 60 10%, diluent unknown 30 Undiluted 90 do. 90 50%, pyrophyllite 30 Undiluted 40 do. 100 do. 76 do. 8 25%, pyrophyllite 99 50%, kaolin clay 53 Undiluted do. 5 do. 60 50%, kaolin clay 45 - 3 Compound Phthalonitrile Piperazine, 1,4-dinitroso-, Propionamide, trichloro-, Pyrethrins + piperonyl cyclonene Ryania Sabadilla Semicarbazide, 1,4-diphenyl-, Sodium fluoroacetate =/ Sodium fluosilicate Sulfone, chloromethyl 4-chloro- phenyl, Tartar emetic Thiocoumarin Xanthydrol Strength and diluent mortality Undiluted 86 25%, pyrophyllite 10 Undiluted 24 0.2% + 2.5%, diluent unkno 1 kvn 43 Undiluted 71 50%, pyrophyllite 35 10% diluent unknown 30 Undiluted 82 do. 94 do. 100 25%, pyrophyllite 100 50%, pyrophyllite 98 5%, pyrophyllite 84 10%, pyrophyllite 82 Undiluted 30 do. 94 50%, pyrophyllite 70 25%, pyrophyllite 30 25%, pyrophyllite 13 In the dust tests sweetpotato plants were grown in 8 -inch flower pots and were dusted while being revolved on a turntable in order to obtain an even distribution of the insecticides. The dusts were applied with small, plunger-type dusters. The compounds were diluted to the percentages of the technical materials shown in the following tabulation. Sifted sand was used around the plants in the pots so that the weevils could be more readily found during observations. Large glass globes, 6 inches in diameter at the base and 11 inches high, were used as cages. Closely- woven cheesecloth, held in place by rubber bands, closed the top end of the cages. Ten weevils were used in each cage, observations made daily for a period of 7 days, and the mortalities recorded. Pyrophyllite was the diluent used in all mixtures unless otherwise indicated. The dust mixtures tested and the resulting mortalities were as follows: 2/ Sodium fluoroacetate is a rodenticide that is extremely toxic to warm-blooded animals. -4- Compound and dilu tion Acetanilide, a.,a., a ,2,5-pentachloro-, 50% Benzene hexachloride (gamma isomer): From technical benzene hexachloride From essentially pure product 5% 4% 3% 2% 1% 4% 1% Chlordane 2%, diluent unknown Chlordane (technical) 25% Chlorinated camphene 25% 15% 10% 5% 1% 3% Ethane, l,l-dichloro-2,2-bis(p-chlorophenyl)-, 50% 25% 3% Ethane, l,l,l-trichloro-2-(p-chlorophenyl-2-phenyl-, 50% Ethane, l,l,l-trichloro-2,2-bis(p-methoxyphenyl)-, (known as methoxychlor) 25% 50% Ether, 4,6-dinitro-m-tolyl methyl, 50% Hydrazine, acetylphenyl-, 3% Hydrazine, 1-isobutyryl- 2 -phenyl-, 50% Parathion 1% 0.5% 0.25% Phenol, 2,2'-(2-chloroethylidene)bis(4-chloro-, 50% Phenol, 2,2 '-methylenebis(4-chloro-, (technical) 50% (pure) 50% Phenol, 2,2'-(2,2,2-trichloroethylidene)bis(4,6-'dichloro-, 50% Propionamide, trichloro-, 50% Ryania undiluted 5% 1% Sabadilla 10%, diluent unknown Sulfone, chloromethyl 4-chlorophenyl, 50% Percent mortality 12 100 100 100 80 80 100 88 97 100 100 100 100 100 100 95 100 96 88 70 92 53 26 40 100 100 100 60 2 10 5 90 56 80 92 In the spray tests, the methods were essentially the same as in the dust tests, except that the mixtures were applied with small, bulb-type applica- tors. The spray mixtures tested and the resulting mortalities were as follows: -5- Compound and dilution Chlordane (emulsion) 24% Chlorinated biphenyl (aqueous solution) 50% DDT (emulsion) 5% 3% 1% 0.75% 0.5% Hexaethyl tetraphosphate (aqueous solution) 0.5% 0.25% 0.06% Naphthenic acid, butyl ester (aqueous solution) 50% Piperonyl butoxide 10%, pyrethrins 1%, and a proprietary emulsifier 0.5%, all in oil, with water 1-99 Piperonyl butoxide 5% and pyrethrins 0.5%, with water 1-400 Piperonyl cyclonene 5% and pyrethrins 0.5%, with water 1-390 Tetraethyl pyrophosphate, with water 1-1600 Percent mortality 100 100 100 100 100 100 100 100 100 20 98 20 In many cases, in both the poisoned-bait tests and the tests on plants, all of the weevils were dead within 48 to 72 hours after treatment. A benzene hexachloride dust containing a minimum of 3 percent of the gamma isomer, a 50-percent trichloropropionamide dust, and emulsion containing a minimum of 0.5 percent of DDT, a chlordane emulsion, and butyl naphthenate and chlorinated biphenyl sprays all caused slight to severe foliage injury when applied to plants in the greenhouse. UNIVERSITY OF FLORIDA 3 1262 09239 2124