Recent Advances in Pasture Pest-Management in the Northern North Island

Withdrawal of the use of cheap, persistent organochlorine insecticides in New Zealand pastures has shifted the emphasis of insect pest control to non-chemical methods during the last 10-15 years. The potential of plant resistance and biological control for achieving major advances in pasture pest management are illustrated by the resistance to Argentine stem weevil (Listronotus bonariensis) of ryegrasses infected by the endophytic fungus Acremonium loliae, the reduction of Australian soldier fly (Inopus rubriceps) populations to subeconomic levels by invertebrate predators, and the effects of pathogens on grass grub (Costelytra zealandica) populations.