Orientation and behavioural responses of Cotesiaplutellae Kurdjumov (Hymenoptera: Braconidae) to cruciferous host plants and host larval body extracts

摘要

The foraging activity of a parasitoid is highly influenced by the chemical cues released from the host plants and their potential hosts in a cropping system. The larval parasitoid Cotesiaplutellae parasitizes the diamondback moth (DBM), Plutella xylostella most efficiently in cruciferous crop ecosystems throughout the world. In this study, we have evaluated and report the effect of hexane extracts of certain selected host plants and larvae of DBM reared on these host plants on the odour preference and orientation behaviour of C. plutellae using multi-armed olfactometer and Y-tiibe olfactometer. The orientation response indicated that host larval body extracts were more attractive and stimulatory to host seeking females than host plant leaf extractsat 1% concentration. Gravid females responded in relatively larger numbers to both host larval body and host plant leaf extracts compared to virgin females. These extracts could be used to enhance the foraging ability of C. plutellae to contain the menace of diamondback moth in cruciferous crop fields.