Influence of plant synomones on the host localisation capability of Trichogramma
Barbara Kagerer, Cornelia Rüdiger, Thomas Schmitt
Biology I, University of Freiburg
The egg parasitoid Trichogramma cacoeciae (Hymenoptera, Trichogrammatidae) is a potential antagonist against the two pest species Lobesia botrana and Eupoecilia ambiguella (Lepidoptera, Tortricidae) which cause major damage in vineyards laying their eggs on the inflorescences and on the berries of Vitis vinifera. It has been already shown that T. cacoeciae uses egg volatiles to locate the eggs of both host species for parasitisation within a short timeframe after oviposition. In further investigated host-parasite systems plant volatiles are known as supplemental cues to be used for host localisation, e.g. Trichogramma brassicae parasitising Pieris brassicae (Lepidoptera, Pieridae) on Brussels sprout. Therefore, we examined the influence of plant synomones on the host localisation behaviour of T. cacoeciae. Both, a potential effect of volatiles from inflorescences and berries are investigated. The results show no positive effect of plant volatiles on the host localisation of the parasitoid. However, T. cacoeciae appears to be negatively influenced in locating eggs on inflorescences. After determining the essential factors for an optimal host localisation and parasitisation, strategies for the use of T. cacoeciae as biological pest control can be developed.