Chemical ecological interactions among grape (Vitis vinifera), grey mould (Botrytis cinerea), and light brown apple moth (Epiphyas postvittana) and their implications in pest management

There is a growing body of knowledge on the ovipositional preference of phytophagus insects and its consequences on the life-history performance of the offspring. The extent to which oviposition choices service the nutritional needs of her offspring remains an open debate. This paper reports a mismatch between the oviposition preference and larval performance of Epiphyas postvittana in a tripartite system with its host Vitis vinifera and commonly co-occurring fungus Botrytis cinerea. Host-seeking gravid female of E. postvittana assessed the infection status of the host plant using olfactory, visual, and tactile cues. In consequence, she laid significantly fewer eggs on B. cinerea-infected V. vinifera. On the contrary, larvae of E. postvittana showed the best performance on B. cinerea-infected V. vinifera viz. greater survival rate, shorter time to pupation, greater pupal mass, and on becoming adults they laid more numbers of eggs than the larvae that were enabled to feed on uninfected berries. External and internal examination of the larvae established that the larvae carry and transport viable conidia of B. cinerea on the body surface and within the gut. Experiments using synthetic nutritional media reveal that the diet incorporated with fungal mycelium improved larval performance and adult reproductive potential.