Efficacy of Trichogramma chilonis parasitizing eggs of lepidopteran pests under laboratory conditions

Nepal adopted the integrated pest management strategy with an emphasis on biological control to be economically and environmentally sustainable. This study aimed for mass rearing of a biological control agent, an egg parasitoid, Trichogramma chilonis on a factitious host Corcyra cephalonica to implement augmentative biological control methods for managing two major lepidopteran pests of corn, Spodoptera frugiperda and Chilo partellus. The objective of this research was to assess the host preference and parasitism efficacy of T. chilonis, after being reared C. cephalonica and to assess its parasitism efficacy after being reared on the S. frugiperda for 10 generations. Our results showed that T. chilonis reared on C. cephalonica has longer development days in lower temperature as compared to higher temperature. The parasitism percentage was 79.30 %, 63.61 % and 21.53 % in eggs of C. cephalonica, C. partellus and S. frugiperda respectively. Trichogramma chilonis prefer to parasitise eggs on the periphery with fewer or no scales rather than heavily scaled part of egg mass of S. frugiperda. The percentage trends of parasitism and emergence over ten generations suggest an inverse relationship which suggest that the parasitoid could be used in augmentative biological control in Nepal.