Effects of Various Insecticide Residues in Cotton on Gender and Developmental Stage of the Insidious Flower Bug (Hemiptera: Anthocoridae)

Orius insidiosus (Say) is an important predator of several economic pests in cotton. Laboratory-reared males, females and third-instar nymphs were exposed to field residues of nine insecticides applied to cotton plants. Insects were caged for 24 h and then removed to determine mortality from 0, 1, 2, 3, and 7-day-old insecticide residues. Insecticides and rates (kg ai/ha) tested were spinosad (0.09, 0.199), indoxacarb (0.78, 0.123), imidacloprid (0.027, 0.053), tebufenozide (0.14, 0.28), methoxyfenozide (0.28, 0.84), abamectin (0.01, 0.02), emamectin benzoate (0.005, 0.01), fipronil (0.042, 0.056), and λ-cyhalothrin (0.014, 0.028). Fipronil and λ-cyhalothrin were the most toxic, causing a significant reduction in survival (up to 3-day-old residues). Abamectin and emamectin benzoate caused significant mortality in predators exposed shortly after application, but survival tended to increase as residues aged. Imidacloprid and indoxacarb were intermediate, causing approximately 50% mortality in this insect. Survival was good in all treatments with 7-day-old residues with the exception of λ-cyhalothrin. Males tended to by more sensitive with lower survival than females.