Lethal and Sublethal Effects of Avermectin B1 on Three Fruit Fly Species (Diptera: Tephritidae)

Topical toxicity of avermectin B1 to Mediterranean fruit fly,Ceratitis capitata (Wiedemann); oriental fruit fly, Dacus dorsalis Hendel; and melon fly, Dacus cucurbitae Coquillett, was assessed over a 21-d observation period. Mortality stabilized 5–21 d after treatment. LD50’s for female D. dorsalis, D. cucurbitae, and C. capitata were 0.021 μg/g (5 d), 0.042 μg/g (15 d), and 0.29 μg/g (10 d), respectively; LD50’s for male D. dorsalis, D. cucurbitae, and C. capitata were 0.012 μg/g (21 d), 0.025 μg/g (15 d), and 0.58 μg/g (5 d), respectively. Doses that caused <25% female mortality significantly reduced fecundity in all three species whether or not males were treated before mating. Fertility was significantly reduced in D. dorsalis but seemed dependent upon whether males were treated and paired with treated females. D. cucurbitae showed greatly reduced fertility regardless of whether treated or untreated males were paired with treated females. Avermectin B1 treatment also reduced fertility in C. capitata, but the effect was minimal.