Topical application, leaf residue, and filter paper residue bioassay methods were used to assess the toxicity of permethrin and methomyl to larvae of the diamondback moth, Plutella xylostella (L.). The objective was to develop an on-farm insecticide resistance monitoring technique for diamondback moth that required only simple, inexpensive equipment and was easy to use. The results of tests using the three bioassay methods led to similar resistance ratios for three diamondback moth strains. Leaf residue and filter paper residue tests using discriminating concentrations could detect the relative susceptibility to permethrin and methomyl in three strains, indicating that both techniques were practical for on-farm resistance monitoring. Third instars were more suitable for the detection of resistance than fourth instars. A monitoring system incorporating concentrations f both the LC90 for susceptible diamondback moth and the recommended field concentration of insecticide is suggested to detect resistance at low levels and to help choose insecticides for the control of diamondback moth strains with higher resistance levels.
Document Type: Research Article
Publication date: August 1, 1993
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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.