MAF mustn’t miss menacing munchers
Forest and Bird is calling on Biosecurity Minister Jim Sutton to investigate how the gum leaf skeletoniser was able to
spread to the point where eradication is now impossible. The Ministry of Agriculture and Forestry today announced that
it had abandoned the option of eradicating the skeletoniser and was adopting a ‘long term management’ approach to
control of the pest.
“The gum leaf skeletoniser has had the opportunity to spread too far. MAF should have been on top of the problem long
before it spread to 25,000 hectares in Auckland. Jim Sutton must make sure that this never happens again,” Forest and
Bird’s biosecurity spokesperson Geoff Keey said.
“The biggest danger to native trees is if the skeletoniser outbreaks in eucalypt shelterbelts or forests and spread to
nearby native forests of rata or kanuka. It will be important to establish buffer zones around areas of rata or kanuka
forest where eucalypt cannot be grown. This will limit the capacity for skeletoniser outbreaks to damage native forest,”
he said.
“It will also be important to put in place measures to prevent the skeletoniser from spreading to the South Island,” he
said.
“Forest and Bird is pleased that MAF responded quickly to Forest and Bird’s request for host testing. The results will
be important in helping to plan the necessary action needed to protect the native forests,” he said.
NOTE
Host testing involves putting eggs and larvae onto plants that might be vulnerable to browsing by the pest. This enables
an assessment to be made as to which plants the pest may eat. As most pests have not eaten native plants prior to
arrival in New Zealand, it is hard to predict what plants may be eaten.
Host testing showed that southern rata and kanuka are the native species most at risk from gum leaf skeletoniser. The
main source of risk appears to be if caterpillars spread from neighbouring eucalyptus trees as very few caterpillars
survived after being hatched on native plants whereas more survived when transferred onto native plants when larger.