Seed treatment for control of wheat insects and its effect on yield

The efficacy of three insecticides as seed treatments for control of insect pests on winter wheat were evaluated over a 4-year period at two locations in Kansas. Their effects on yield also were measured. Imidacloprid (Gaucho (R)) and thiamethoxam (Adage (R)) were effective in controlling early seas on (fall) infestations of the greenbug, Schizaphis graminum (Rondani), and the Russian wheat aphid, Diuraphis noxia (Mordvilko) at all rates tested. C ontrol of spring infestations with those two compounds was less consistent. Fipronil (Regent (R)) was not effective against these two aphid species. A ll three compounds effectively controlled fall infestations of Hessian fly, Mayetiola destructor (Say), but none were effective against the sole sprin g infestation that occurred. Imidacloprid had no insecticidal effect on fal l armyworm, Spodoptera frugiperda (Smith), in a single fall test. Under low or nonexistent natural pest infestations, no yield benefits were observed from any of the seed treatments. No phytotoxicity or negative effects on yi eld were detected.