Field Evaluation of Candidate Insecticides for Control of the Southern Corn Rootworm on Peanuts in Virginia1

Selected, soil-applied, granular insecticides were tested for 3 years against larvae of Diabrotica undecimpunctata howardi Barber attacking peanuts, Arachis hypogaea (L.). Percent damage of immature fruit was significantly reduced by treatments of Landrin® (4:1 mixture of 3,4,5- and 2,3,5-trimethylphenyl methyl carbamate) and diazinon. Bux® Insecticide (4:1 mixture of m-(1-methylbutyl) phenyl methylcarbamate and m-(1-ethylpropyl)-phenyl methylcarbamate), Landrin, aldicarb, UC-8454 (5,6,7,8-tetrahydro-I-naphthyl methylcarbamate), carbaryl, diazinon, parathion, and phorate significantly reduced damage to mature, fruit. At another site, carbaryl and parathion failed to significantly reduce rootworm damage on immature fruit, whereas phorate, diazinon, carbofuran. and Dyfonate® (O-ethyl S-phenyl ethylphosphonodithioate) gave good control. All treatments except parathion reduced damage in mature fruit. Planting-time band applications of carbofuran at 2.0 and 4.0 lb AI/acre gave rootworm control equal to applications of phorate at planting followed by diazinon at pegging. Yields were significantly increased by pegging-time applications of Dyfonate at 1.5 lb AI/acre and carbofuran at 2.0 AI/acre in 1 test, by the application of carbofuran at 4.0 lb AI/acre at planting time, and by an application of 1.0 lb phorate at planting followed by 2.5 lb diazinon at pegging in a 2nd test.