AgResearch scientists are warning that black beetle numbers in the North Island could explode if there's a mild winter.
Black beetles, which eat pasture and damage some crops, are established in the upper half of the North Island, down to Taranaki and Hawke's Bay.
AgResearch says trials show that black beetle populations are on the increase and their development is more advanced this autumn than in the previous five years.
Biocontrol and biosecurity team leader Dr Alison Popay says it means that if warm conditions continue through autumn and spring conditions are right, some farmers could be facing another serious black beetle outbreak next summer.
