The focus is on the innocuous nasturtium as the Department of Conservation turns up the heat on Nelson's great white butterfly invasion.
The flowering creeper is a favoured host plant for the butterfly, which was found in a Nelson home garden in mid-2010, has established a population across city and Richmond gardens, and is seen as a threat to commercial and private brassica crops. It could also harm native cress.
DOC is asking residents for help to find patches of uncontrolled nasturtium, which are breeding hotspots for the pest.
"We are asking residents within the Nelson city area to let us know of any areas of nasturtium growing rampant on properties or in public areas that they know of," said DOC Motueka area manager Martin Rodd, who is fronting the great white eradication campaign.
"We also encourage property owners to remove nasturtium to assist in eradicating the pest butterfly and avoid the nasturtium attracting great white butterfly infestations.
"Those who want to keep nasturtium are asked to regularly check it for great white butterfly caterpillars and eggs. Watch should also be kept for infestations on brassica vegetables, such as broccoli and cabbage," Mr Rodd said.
The tiny yellow eggs and caterpillars are found in clusters. The caterpillars in later stages are speckled black and greyish-green, with three yellow lines along their bodies.
Nelson and Richmond are the only places in New Zealand where the great white has been found.
Calls about nasturtium can be made to the Nelson DOC office on 03 546 9335, or email email@example.com. Suspected finds of caterpillars and eggs should be reported to the Ministry for Primary Industries, 0800 80 99 66.
- © Fairfax NZ News
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