Date: 01 February 2013
Nasturtium is a favoured host plant of the great white butterfly in Nelson Tasman and areas of uncontrolled nasturtium are key breeding sites for the pest. The DOC-led multi-agency attempt to eradicate the great white butterfly has stepped up efforts to clear wild nasturtium to eliminate these breeding hotspots.
'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.
'Calls about uncontrolled nasturtium can be made to our Nelson DOC office on +64 3 546 9335 or an email can be sent to email@example.com.
'We also encourage property owners to remove nasturtium to assist in eradicating the pest butterfly and avoid the nasturtium attracting great white butterfly infestations.
‘We appreciate not everyone will want to remove their nasturtium. An option is to cut it back to a smaller size which is easier to keep an eye on. Usually the seeds remain in the soil and it will grow back so it would need ongoing management.
‘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.'
Calls to report suspected finds of great white butterfly caterpillars and eggs should be made to the Ministry for Primary Industries (MPI) hotline 0800 80 99 66.
The tiny, yellow eggs and caterpillars are found in clusters on host plants. The caterpillars are very small when young and in later stages they are speckled black and greyish-green with three yellow lines along their bodies.
DOC and Nelmac Ltd, under contract to DOC, are clearing nasturtium with agreement being sought from property owners. It is mostly being pulled out by hand but, where necessary, herbicide is being used with householders' approval.
The multi-agency attempt to eradicate the pest butterfly was launched at the end of last year and is being run in conjunction with Vegetables New Zealand, MPI, Nelson City Council and Tasman District Council. The work is being carried out by Nelson company Entecol Ltd and DOC staff.
The eradication attempt aims to stop the great white butterfly becoming a major New Zealand pest. The species poses a serious threat to commercial and home brassica vegetables crops and to endangered native cresses.
DOC Nelson Marlborough Conservancy communications advisor
Phone: +64 3 546 3146