Don't hand on scraps, says DOC
Passing on brassica vegetables, scraps and garden waste risks spreading the great white butterfly and the Department of Conservation is asking residents of Nelson and Tasman to be vigilant.
DOC is leading a campaign to stop the spread of the pest, first found in a Nelson city garden in 2010, and eradicate it.
DOC spokesman Bruce Vander Lee said people often helpfully passed on vegetables and seedlings to others or vegetable scraps for chook food, for example.
"We are asking people to avoid doing this as much as possible from Nelson and Richmond and surrounding areas to reduce the risk of great white butterfly eggs or caterpillars being moved with it.
"If people do need to pass on brassica vegetables or other vegetable matter, we ask they carefully check it first."
DOC has also repeated the call for Nelson and Tasman residents to check campervans and caravans for great white butterfly pupae before taking them outside the Nelson area.
The great white poses a serious threat to endangered native cresses and home and commercial brassica crops, including crops for cattle and sheep feed.
DOC is attempting to eradicate the butterfly in Nelson Tasman to prevent it spreading elsewhere in New Zealand and becoming a permanent, widespread pest.
DOC is also asking people in and around Richmond and in areas around Nelson city to be particularly alert over summer for the butterfly and its caterpillars and eggs.
In three years the butterfly has spread across the Port Hills to Stoke and was found in Richmond for the first time last January.
Mr Vander Lee said one male butterfly had recently been found in Hope, with a search of the area showing no other sign of infestation, and an egg cluster in Richmond.
"We've done a search around that and the last property we went to the lady had caught a female butterfly - we're hopeful that we've picked that one off."
DOC has a team of 20 to 25 in the field each day, drawn from a pool of 40 workers. Mr Vander Lee said the spring offensive in Nelson gardens and parks had donea good job, with lower numbers being found in the core areas.
With the public's help, the chances of eradicating the pest were as strong as ever, he said.
The clusters of tiny yellow eggs and caterpillars are found on the butterfly's favoured plants, particularly nasturtium and honesty and brassica vegetables such as broccoli and cabbages. The caterpillars are very small at first and in later stages are speckled black and greyish-green with three yellow lines along their bodies.
The pupae are greyish-white or pale green, 25-millimetres long, distinctively dotted with yellow and black spots, and have blunt-spiked ridges.
Anyone seeing the butterfly's eggs or caterpillars is asked to report the find to the Ministry for Primary Industries hotline 0800 80 99 66. DOC staff will then respond.
Information to help identify the eggs and caterpillars can be found at doc.govt.nz
The Nelson Mail