Parasitoids associated with codling moth (Cydia pomonella) in apple-growing regions in New Zealand
Codling moth (Cydia pomonella) (CM) is a major pest of apples in New Zealand. Several biocontrol agents introduced in the past to control CM have only been partially successful at reducing CM populations, so a parasitoid wasp, Mastrus ridens (Hymenoptera: Ichneumonidae), was recently released into apple-growing regions. This study sought evidence of the establishment of CM parasitoids. Corrugated cardboard bands (2-cm wide bands with sentinel CM larvae and 10-cm wide empty bands to trap wild CM larvae) were used to assess the presence of M. ridens and other CM parasitoids in Hawkeâ€™s Bay, Nelson, Central Otago and Waikato regions. Five CM parasitoid species, including M. ridens, were recovered from sentinel and wide bands. Liotryphon caudatus (Hymenoptera: Ichneumonidae, released to control CM in 1906) was found in Hawkeâ€™s Bay and Waikato. Ascogaster quadridentata (Hymenoptera: Braconidae, released to control CM in the 1930s), Glabridorsum stokesii (Hymenoptera: Ichneumonidae, released in 1967 to control light brown apple moth), Dibrachys microgastri (Hymenoptera: Chalcidoidea: Pteromalidae, an accidental arrival) and M. ridens were found in all regions. The interspecific competition between M. ridens and other parasitoid species remains to be investigated.