Developmental biology of two species of leafroller egg parasitoids

Abstract

Leafrollers (Lepidoptera Tortricidae) are important pests of many horticultural crops Leafroller eggs in New Zealand are attacked by the trichogrammatid parasitoids Trichogrammatoidea bactrae and Trichogrammanza funiculatum (Hymenoptera Trichogrammatidae) Conventionally trichogrammatids are used for pest control through augmentation of numbers by making mass releases Laboratory tests have been carried out to ascertain the potential of the two eggparasitoid species to act as biological control agents for the key leafroller pests in New Zealand T funiculatum had a slightly slower developmental rate than T bactrae Temperature did not significantly affect the number of eggs parasitised by the adult parasitoids over their lifetime but temperature did affect the percentage of adult parasitoids emerging from parasitised eggs T bactrae had higher net reproductive rates and intrinsic rates of increase than T funiculatum and at this stage appears to be the most suitable candidate for an augmentative biological control programme