NZ weed biocontrol successes
A review of the efficacy of biocontrol agents introduced to control invasive weeds in New Zealand has confirmed the variation in success rates. Benefits from the 33 introductions targeting 23 weed species considered by the review ranged from massive to negligible, according to the five-point scale used by New Zealand’s Environmental Protection Agency (EPA), which considers economic, social and environmental risks and benefits. Around two-thirds (23) of the introductions had negligible or minimal benefits, two had minor, five moderate, one major and two massive beneficial effects. Overall benefits to the New Zealand economy from introduced biocontrol agents are estimated at NZ$11-21 million (US$9-17 million) per year.