FIELD AND LABORATORY PERFORMANCE OF NOVEL INSECTICIDES AGAINST ARMYWORMS (LEPIDOPTERA: NOCTUIDAE)

Abstract

Beet armyworm, Spodoptera exigua (Hubner), and fall armyworm, Spodoptera frugiperda (J. E. Smith), are occasional pests of cotton, Gossypium hirsutum (L.), and soybean, Glycine max (L.) Merrill. These insects can be difficult to control due to insecticide resistance and larval behavior on plants. The objectives of these studies were to determine the efficacy of selected insecticides against native infestations of beet armyworm in cotton and soybean and to generate baseline dose-mortality responses for beet armyworm and fall armyworm adults to indoxacarb and pyridalyl in the adult vial test. Indoxacarb, pyridalyl, spinosad, methoxyfenozide, and emamectin benzoate controlled beet armyworm infestations up to 10 d after treatment compared to the non-treated control. Thiodicarb reduced beet armyworm densities up to three d after treatment. The LC50 values of indoxacarb and pyridalyl for beet armyworm and fall armyworm exceeded the highest concentrations tested (100-200 μg/vial) in the adult vial test. Dose-mortality values of indoxacarb and pyridalyl were higher than discriminating concentrations of cypermethrin, methomyl, profenofos, and endosulfan used in the adult vial test for monitoring tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie), susceptibility in Louisiana and Texas. These results indicate that the adult vial test may not be the most efficient test method for indoxacarb and pyridalyl in insecticide susceptibility monitoring programs.