Impact of Insecticides on Reproduction of Melon Fly Zeugodacus cucurbitae (Coquillett)

The melon fly, Zeugodacus cucurbitae (Coquillett), is a major pest infesting cucurbitaceous fruits. Insecticides are widely used to manage this pest. However, due to the internal feeding behaviour of maggots and the limited exposure of adult flies to treated fruits during oviposition, the effectiveness of insecticides in the field can vary. This study examined the impact of commonly used insecticides on the survivorship and reproduction of Z. cucurbitae. Adult melon flies were exposed to insecticide treated ivy gourd fruits for 10 days. The results showed that spinosad, malathion and fipronil caused significant adult mortality, reduced fruit infestation, decreased progeny production with more malformed progenies. Deltamethrin reduced progeny production without causing mortality. Cyantraniliprole and azadirachtin were found to be ineffective. These findings underscore the importance of selecting appropriate insecticides for the control of Z. cucurbitae.