Third-instar F1, progeny of several field-collected strains of soybean looper, Pseudoplusia includens (Walker), were exposed to artificial diet that was surface-treated with several concentrations of selected insecticides (permethrin [Ambush], Bacillus thuringiensis variety kurstaki [Condor OF), thiodicarb [Larvin], chlorfenapyr [Pirate],emamectin benzoate [Proclaim], or spinosad [Tracer]). LC50 s (72 h) for field strains were compared with a susceptible USDA reference strain to evaluate possible tolerance to these insecticides. Significant differences were found among LC50 s of all field strains and the susceptible USDA reference strain in the permethrin bioassays and among several field strains and the USDA strain in the B. thuringiensis, thiodicarb, and emamectin benzoate bioassays. In the chlorfenapyr bioassays, only 1 field strain from Winnsboro, LA, had a significantly greater LC50 than that of the USDA strain. In the spinosad bioassays, the only field strain with a significantly different LC50 than that of the USDA strain was the strain collected from Hamburg, LA, and this strain had a lower LC50 than that of the USDA strain. These data will serve as a historical database for monitoring soybean looper resistance to these compounds and should prove useful in the development of an insecticide resistance management program for this pest.
Document Type: Research Article
Publication date: October 1, 1997
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.