Resistance to pyrethroid insecticides was diagnosed in Heliothis virescens (F.) from cotton fields in Texas in 1985 and in Mississippi in 1986. Susceptible third instars on cotton terminals sprayed with recommended rates of pyrethroids suffered 90-95% mortality; however, only 20-71% of the field-collected, resistant larvae died. We confirmed the presence of pyrethroid resistance in Texas in 1985. Topical application bioassays in the laboratory failed to show more than sixfold resistance levels in larvae of some of these strains from Texas and Mississippi,indicating that standard topical bioassays do not always accurately diagnose resistance in this species. However, the frequency of resistant phenotypes in the cotton terminal assays and results with an adult bioassay technique were highly correlated.
Document Type: Research Article
Publication date: October 1, 1989
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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.