May 19* LIBRARY J* 620 STATE PLANT BOARD United States Department of Agriculture Agricultural Research Administration Bureau of Entomology and Plant Quarantine LABORATORY TESTS OF TOXICITY OP SOIE ORGANIC COMPOUNDS TO THE EUROPEAN CORN BORER, JANUATO— -MARCH 1°M By D. D. (Juestel, Division of Cereal and Forage Insect Investigations, and C. V. Boven and S. I. Gertier, Division of Insecticide Investigations This report contains results of laboratory tests with recently decoded organic compounds showing their toxicity to newly hatched larvae of the European corn borer. Tests with other compounds against these larvae are reported in publications B— 557 and E-612 of this Bureau. The care and handling of larvae, moths, and eggs for these tests and the technique employed in conducting them are described in an earlier report. All tests were run for Ug hours. Cauliflower leaves were used as the feeding medium. Materials were tested as sprays at a strength of k pounds per 100 gallons of water containing l/3 pound of Areskap (sodium monosulfo- nate of butylphenylphenol) as a wetting agent. Those materials showing high mortality with little or no feeding were retested at either 2 pounds or 1 pound per 100 gallons of water, or both. Only two compounds gave high mortal ity when the concentration was reduced to 2 pounds per 100 gallons, and only one, 4,6-dinitro-o-cresol ether, continued to give high mortality when tested at 1 pound per 100 gallons. As this material is not ground readily by itself, various mix- tures with talc and pyrophyllite were prepared and tested against the borer. Concentrations as low as l/h pound of active agent per 100 gallons of water gave 100 percent mortality or nearly so in repeated tests. The degree of fineness with which the material was ground in- fluenced the mortality. When such small insects as newly hatched European corn borer larvae are being used for tests, the active agent must be finely ground for ingestion and for the material to be carried between the appressed leaves '-There the borers feed in the field. Since approximately 99 percent of the borers killed by derris spray treatments in the field die when they are in the first or second instar, the neces- sity for small particle size of the active agent can readily be seen. 'The results of these teste are given in table 1. - 2 - Table 1.— 'Results of laboratory tests of some organic compounds against newly hatched European corn borer larvae. Compound Larvae used in treat- ment 1/ Average mortality of larvae Not Treated treated Amount of feeding 2/ Number Percent Percent Tests at k pounds par 100 gallons 4,6-Dinitro-o-cresol ethyl ether (M0 2 ) 2 k 2.1 «•+♦ 1-Benzoylurea CgHcCONHCOH^ 153 2.k 1.7 ♦♦♦ H-I so butyl cinnamlde 15s 1.9 .0 *++ CgH^CHlCHCONHfyHo, N'-Benzylidene-N.N'-dimethyl- 166 1.8 1.1 ♦♦«■ p-phenylenedi amine Cgl^CHiNCgE^CCI^ Cydopentanone oxime - . 81 1.6 4.8 «•♦♦ CH2(CH 2 ) 2 0H 2 0:NOH 2-3Turaldehyde U-phe^rl-3- 190 1.6 1.7 ♦♦♦ thioaemicarbazone ( O^jO ) CH: IWHCSBHCgHK Salicylaldoxime C63^(0H)CHsK0H 111 1.I4 2.1 ttt l-Phenyl-3-(phenylthioureido)- I85 1.4 1.7 ♦♦♦ 2-thiourea (CgH 5 niCSNH-) 2 Ethyl ideneurea OHjCJ^HCCJH 180 1.2 .7 ♦«•♦ 2-Furanacrolein U-phenyl-3- thiosemicarbazone 175 1*1 1*7 *♦♦ (Ci^H,0 ) CH: CHCH.'NNHCSNHCgHc U-Cl^-Dibromoetbyl) toluene 100 1.0 .7 ♦♦♦ OHiOgH^CHlrCB^Br 4-Phenylmorpholine 119 .8 1.9 t*# (C 6 H^)N(C H 2 ) 2 0(C H 2 ) 2 , 2,5-Bis(p-methylphenoxy) 172 .8 1.7 ♦«• l,4-cyclohe;-aJiedione CH3C6Hl|OCHCOCH 2 CH(OC5%CH 3 )COCH 2 - If ^ UNIVERSITY OF FLORIDA SI1111IJI1I 3 1262 09239 1324 Tahle 1. — Continued Compound Larvae Average mortality used in of larvae treat- Hot ment 1/ Treated treated Amount of feeding 2/ ttum"ber Percent Percent Setts at k pounds per 100 gallons - Cont. Ben z aldehyde U-phenyl-3- thiosemicarbazone CgHKCHtBIHCSEaOgHj H-p-Tolyl cinnamamide GgltGH: GHCOKHCgH^CH^ Cinnamanilide CgHcCHsCHCONHOgH^ 157 169 189 • 7 N-o-tfolylcinnamamide OgUSRi CHCONHCgH^CH, 190 Cinnamamide C/tHcCHjCHDNH l 6 H 5 ( 183 •5 .0 .0 Tests at 2 pounds per 100 gallons ^,6-Dinitro-o-cresol ethyl ether 110 100.0 (HO^CH^GgHgOCgHj Ethyl ideneDlsoenSamlde CEUCHClTHCOCgHjg 1^7 93.1 Salicylaldehyde U-phenyl-3~thiosemlcar"ba- $Q lU.O zone C£Hij.(QH)0H:MKCSNH06Hc d-Camphor oxime C1QH37NO 83 6.7 Cinnamaldehyde 4-phenyl-3-thio semi carta- 70 1»^ zone CgHcCHtCHCHtlTNHCSNHCgHc 1-Benzoyl thiourea C^HeCONHCSHB^ 75 1«3 ^-Phenylthiosemicarhazide CgHcNHCSNHKH 2 77 1.3 Tests at 1 pound per 100 gallons ^,6-Dinitro-o-cresol ethyl ether 211 100.0 (NOgJgCCEjJCgHgOOgHj Ethyl ideneDishenzamide CH,CH0raCOCgH,j) 2 78 lU.l 1.7 .0 .0 .0 .0 2.5 2.5 2.1 2.5 2.5 2.5 •3 1.5 ♦♦to *♦+ ♦+♦ «•+♦ ♦*♦ 1/ Approximately the same numher of larvae were used in the nontreated tests. 2/ 0, none; ♦, little; t*t moderate! ♦♦♦, much.