Evaluation of Trichogramma brassicae for the control of carnation tortrix mothand light brown apple moth in protected nursery stock

Abstract: Initial experiments using insect cages to contain host and parasitoid showed thatTrichogramma brassicae (as Tricholine from Syngenta Bioline Ltd.) were able to successfullyparasitise egg masses of carnation tortrix moth (Cacoecimorpha pronubana), providing that theeggs were young and pale green when parasitoids were active. Egg masses turned black about 10days after being parasitised. Mature egg masses, which were yellower in colour, were notparasitised. Tests in the laboratory showed that Trichogramma adults emerged from parasitisedeggs on cards between 9 and 13 days (mean 11 days) after delivery. This time interval needs tobe taken into account when planning introductions of this beneficial. A further trial onChaenomeles plants in a polythene tunnel on a commercial nursery, which were naturallyinfested with light brown apple moth (Epiphyas postvittana), showed that weekly introductionsof the parasitoid at 20 per m2 between mid June and mid September gave good control over thisperiod, although two applications of Dipel DF (Bacillus thuringiensis) were also needed to ensurecomplete control.