ABSTRACT
In 1992, bollworm moths were captured in pheromone traps in central (Boone County), southwest (Vernon, Barton, and Jasper Counties), south central (Wright County), and southeast (Stoddard, New Madrid, and Dunklin Counties) Missouri. Fifteen bollworm traps captured a total of 80,744 moths. Four tobacco budworm traps (Wright, Stoddard, New Madrid, and Platte Counties) captured only 83 moths. Results of 25 conducted on bollworm moths captured in Boone (n = 6), Wright (n = 11), Vernon (n = 5), and Barton (n = 3) counties revealed that about 9% and 1% survived exposure to cypermethrin concentrations of 2.5 and 5.0 µg/vial, respectively. Cypermethrin LC(50) values (n = 7) ranged from 0.30 to 0.96 µg/vial. Piperonyl and amitraz synergized the toxicity of cypermethrin to bollworm moths. Based on these bioassays, there was no evidence of increased pyrethroid tolerance in bollworm moths.
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