Development of Trichogramma australicum Girault (Hymenoptera: Trichogrammatidae) in fertile and infertile Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) eggs

Abstract

Trichogramma australicum wasps were reared in fertile and infertile Helicoverpa armigera eggs. In one experiment, all parasitised and unparasitised infertile moth eggs collapsed 48–60 h after they were laid and no wasps emerged. In a second experiment, 20% of parasitised infertile eggs (<12 h old) produced adult wasps but their number was significantly lower (P < 0.05) than those from fertile eggs. Conversely, almost all parasitised fertile eggs produced T. australicum adults and all unparasitised fertile eggs produced H. armigera larvae. The number of wasps emerging per egg from fertile and infertile host eggs was not significantly different (P > 0.05). No significant differences (P > 0.05) were noted in the number of progeny produced by female wasps reared in fertile or infertile eggs. It is recommended that only fertile H. armigera eggs be used to mass rear T. australicum.