Potential for Mass Rearing of the Egg Parasitoids, <em>Trichogramma chilonis</em> and <em>Tricogramma achaeae</em> (Hymenoptera: Trichogrammatidae) on <em>Corcyra cephalonica</em> Eggs

Trichogramma chilonis and T. achaeae are egg parasitoids, considered as ideal candidates for managing the cabbage looper ( Trichoplusia ni ) through augmentative release. Mass rearing with steady supply of parasitoid is necessary to promote augmentative release. Numbers of factors contribute to the steady supply of parasitoids. Corcyra cephalonica eggs are extensively used for mass rearing. When there is an excess supply of host eggs, those eggs should be stored and used for parasitization when needs arise. Further, steady supply of parasitoids can be assured if parasitized eggs can be stored when there is excess supply. Adult parasitoids should be maintained as a parent stock and they should be fed with suitable food at the right concentration using a suitable feeding technique. In addition, it is important to know how many generations of parasitoids can be run continuously on C. cephalonica eggs without losing the parasitization capacity. These aspects were studied with the objective of improving the existing mass rearing protocol. T. achaeae and T. chilonis accepted stored eggs for parasitization, but the level of acceptance significantly varied with storage durations. The C. cephalonica eggs stored for two weeks at 4 or 8°C were acceptable for parasitization. Pupal stage of both parasitoids within parasitized eggs can be stored upto two weeks at 4°C or four weeks at 8°C while maintaining at least 70% adult emergence. Performance of emerging adults in terms of parasitism significantly varied with storage duration. Bee honey was a better type of food source compared with glucose, fructose and sucrose for feeding parasitoids. The parasitoid adults can be fed with 50% bee honey using drop method successfully. Both species responded differently for number of generations that can be run on C. cephalonica eggs. It was four generations for T. achaeae and eight for T. chilonis.