Egg parasitoids in vegetable crops ecosystem: Research status and scope for utilisation

Abstract

In vegetable ecosystem, the egg parasitoids are mainly trichogrammatids (Trichogramma, Trichogrammatoidea) on Lepidoptera and scelionids (Telenomus, Trissolcus) on Lepidoptera and Heteroptera, besides mymarids on leafhopper and thrips. Trichogramma chilonis is found promising as natural and augmentation control agent for several lepidopteran pests. Considerable progress has been made on utilising kairomones for improving the performance of T. chilonis. Release systems could be refined to match with host abundance pattern, while a novel method of spraying parasitised eggs has been found promising. Inundative releases of T. chilonis, T. brasiliensis and T. pretosium for Helicoverpa control in tomato, okra and chilli, besides T. chilonis for Leucinodes orbonalis on brinjal, have been demonstrated as effective. Similar promising results have been obtained from T. bactrae release in controlling Plutella xylostella on cabbage. Integration of egg parasitoid release with NVP, neem and pheromone trap has been shown possible in IPM modules. The scope of mass rearing of Telenomus remus on Corcyra cephalonica has been demonstrated, while further improvements in their efficiency are required. The present constraint in mass production and storage of T. achaeae may merit attention. Further research may focus also on strains collection for stress adaptation, on host searching and also on field dispersal and utilisation of semiochemicals for improving the field performance of mass-released parasitoids. .