Toxicity of Selected Insecticides to Fall Armyworms (Lepidoptera: Noctuidae) in Laboratory Bioassay Studies

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Florida Entomological Society is collaborating with JSTOR to digitize, preserve and extend access to The Florida Entomologist. ABSTRACTEfficacy of conventional and experimental insecticides against the fall armyworm, Spodoptera frugiperda (J. E. Smith), was evaluated in laboratory bioassays. In a laboratory diet bioassay, third instars of a laboratory-strain were more susceptible to novel insecticides, including chlorfenapyr, methoxyfenozide, spinosad, and tebufenozide, than to a recommended insecticide, thiodicarb. In other laboratory bioassays, fall armyworms were fed field grown cotton leaves, white flowers, or bolls treated with one of two recommended insecticides, L-cyhalothrin or thiodicarb, or one of four experimental insecticides, chlorfenapyr, emamectin benzoate, methoxyfenozide, or spinosad. First instar mortality was significantly greater on leaves treated with chlorfenapyr, L-cyhalothrin, or thiodicarb than for the untreated control at 24 h after infestation (HAI). First instar mortality was significantly greater on leaves treated with all insecticides, with the exception of methoxyfenozide, than for the untreated control at 48 HAI. Likewise, first instar mortality was significantly greater on white flowers treated with all insecticides, with the exception of methoxyfenozide, than for the untreated control at 24 HAI. First instar mortality on white flowers treated with all insecticides was significantly greater than the untreated control at 48 HAI. Fifth instar mortality on bolls was not significantly different among treatments at 1 day after infestation (DAI). At 3 and 5 DAI, fifth instar mortality was significantly greater on bolls treated with all insecticides, with the exception of methoxyfenozide and spinosad, than for the untreated control. At 7 DAI, fifth instar mortality was significantly greater on bolls treated with all insecticides, with the exception of spinosad, than for the untreated control. These data indicate that these recommended and experimental insecticides are effective in controlling early fall armyworm instars on cotton if larvae come in contact with these insecticides.

TOXICITY OF SOME CONVENTIONAL AND NONCONVENTIONAL INSECTICIDES AGAINST COTTON LEFWORM, Spodoptera littoralis (BOISD.)

“…While, methomyl was the fourth one, its LC 50 value was 562.073 ppm after 24 hrs. These results are in agreement with those obtained by Adamczyk et al (1999), they reported that novel insecticides chlorfenapyr, methoxyfenozide, spinosad and tebufenozide were more toxic than conventional insecticide thiodicarb toward the third instar larvae of fall armyworm, S. frugiperda using diet bioassay. Moreover, Argentine et al (2002) found that the emamectin benzoate was consistently the most toxic insecticide; it was 20-to 64.240-times more toxic than chlorfenapyr, fipronil and tebufenozide.…”

First Report of Outbreaks of the Fall Armyworm Spodoptera frugiperda (J E Smith) (Lepidoptera, Noctuidae), a New Alien Invasive Pest in West and Central Africa

“…Hence control with contact insecticides is often ineffective though it remains until today the most widely practiced management measure. Its frequent overuse has led to the emergence of regional populations resistant to several classes of pesticides [15] and favoured the use of transgenic Bt-maize. Thus, cultivars expressing the Cry1F toxin against insect defoliators are currently widely commercialized in the western hemisphere.…”

Initial detections and spread of invasive Spodoptera frugiperda in China and comparisons with other noctuid larvae in cornfields using molecular techniques

“…In addition, larvae usually bore into corn whorls or ears and develop under protected conditions, which allows them to avoid direct exposure to insecticides. This greatly increases the chance of survival for S. frugiperda during insecticidal sprays and low‐dose exposure to insecticides probably has contributed to their resistance to several classes of insecticides (Adamczyk et al ., ; Gutiérrez‐Moreno et al ., ).…”