The Department of Conservation says great white butterfly activity could pick up in coming months after no detections for more than three months and it is calling on the public to help find the last of the pests to get them down to zero.
DOC’s Great White Butterfly Project Manager Michael Shepherd said autumn was a peak period for great white butterfly breeding and a critical stage for the programme to eradicate the pest butterfly.
Great white butterfly
“It’s encouraging to have had no great white butterfly detections in Nelson since an adult male was caught on 16 December but some great white butterflies stay dormant as pupae through the summer heat. The butterflies start emerging from pupae from now and start to breed.
‘It’s crucial we find all great white butterfly eggs, caterpillars, pupae and butterflies to suppress breeding and eliminate the last of the pests.
“Our eradication team will continue searching gardens for butterfly infestations but we are also counting on the public to look for great white butterflies and their eggs, caterpillars and pupae and to report any found to the Ministry for Primary Industries hotline 0800 80 99 66.
‘We’re asking for the great support we’ve had from Nelson-Tasman residents for eradicating the great white butterfly to continue to help us mop up what’s left of the pest butterfly population.’
It was confirmed in December that the pest butterfly population had been knocked down to a low level. The current ‘mop-up’ phase will be followed by a ‘surveillance’ phase, with garden searches continuing to confirm the butterfly has been eradicated.
The DOC-led effort to eradicate the great white butterfly was launched in November 2012 to clear it from Nelson-Tasman, where it is only found, and to prevent it spreading to the rest of New Zealand. The butterfly poses a threat to endangered native cresses and to commercial and home brassica crops, including dairy and sheep farm crops.