The Department of Conservation is asking Nelson Tasman residents to ensure the great white butterfly is not spread with brassica vegetables or vegetable waste being passed on.
DOC spokesperson Bruce Vander Lee said there was a major risk of the pest butterfly being spread to new locations through eggs or caterpillars being moved with vegetables, vegetable scraps and garden waste.
“People often helpfully pass 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 to ensure there are no great white butterfly eggs and caterpillars with it.
“The butterfly needs to be kept to a limited area if we are to succeed in eradicating it. We need the local community’s help to prevent it spreading.”
DOC has also called on Nelson Tasman residents to check campervans and caravans for great white butterfly pupae before taking them outside the Nelson area.
The great white butterfly 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.
The butterfly has mostly been within Nelson city over winter and spring but the butterfly seems more likely in summer to fly further out to surrounding areas. The pest butterfly was found in Richmond for the first time last January.
Anyone seeing the butterfly’s eggs or caterpillars is asked to report it to the Ministry for Primary Industries hotline 0800 80 99 66. DOC staff will then respond.
The clusters of tiny, yellow eggs and caterpillars are found on the butterfly’s favoured plants particularly nasturtium, honesty and brassica vegetables such as broccoli and cabbages. 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 mm long, distinctively dotted with yellow and black spots, and have blunt-spiked ridges.