Host Finding Behaviour Of The Egg Parasitoid, Gryon Pennsylvanicum (Hymenoptera: Scelionidae)

The squash bug, Anasa tristis (De Geer) is a serious pest of cucurbit crops. The egg parasitoid, Gryon pennsylvanicum (Ashmead), is the primary parasitoid of the squash bug and has been considered as a biological control agent. In the present study, we conducted both laboratory and greenhouse bioassays to determine the effects of kairomones emitted by A. tristis on the host searching behaviour of G. pennsylvanicum. Chemicals were extracted from A. tristis eggs, unmated females and males, and mated females and males. The percentage of females responding to extracts was significantly higher for egg extracts than the other extracts tested. In greenhouse tests, percent parasitism of egg masses baited with extract-treated lures was significantly higher than for those treated with solvent-treated control lures for all six extracts tested: ethanol and hexane extracts of eggs, mated females and mated males. Further research on kairomones of A. tristis may result in the development of synthetic lures that could be used in squash fields to increase parasitism by G. pennsylvanicum. The promising results from this study highlights the potential application of kairomones in enhancing the efficacy and effectiveness of biological control programmes and should be of interest to growers and pest control professionals.