Helicoverpa parasites
Wasps
Other Helicoverpa parasites are very difficult to identify in the field. Minute wasps, sp. (as shown in the picture) and Telenomus sp. attack eggs. Parasitised eggs turn black after 3 days and fail to hatch. One or more small, parasitic wasps may emerge from an egg 8 to 10 days after parasitisation . Egg parasitoids are most abundant later in the season from January to March and tend to reach higher levels of parasitisation in the northern cotton areas compared with the southern ones. The Trichogramma pretiosum was introduced into Australia for pest control purposes and occurs in some of the cotton growing regions along with the native Trichogramma species. Pest managers can also purchase commercially available Trichogramma pretiosum to release into crops.
Two exotic species of larval parasitoids of Helicoverpa, Cotesia kazak (Telenga) and Hyposoter didymator Thunberg, have been released in east Australian cropping regions since 1991. These wasps lay their eggs in small Helicoverpa larvae and the host dies as a medium larva . Each wasp species forms a characteristic pupal cocoon. The establishment of these species in our cropping areas will complement the action of native Helicoverpa parasitoids e.g. Microplitis.
Several species of flies such as Carcelia spp. and Goniophthalmus spp. (family Tachinidae) parasitise larvae. Some kill the larva while others kill the pupa. The Tachinid larvae feed within the host larvae and the adult flies emerge from the pupae.
Argyrophylax proclinata Crosskey, the yellow peach moth parasite, is another Tachinid which parasitises yellow peach moth larvae in a similar manner.
