Karioi possums poisoned

Ruapehu Bulletin, Volume 8, Issue 383, 23 April 1991, Page 3

Karioi possums poisoned

Pest destruction staff of the regional council have recently completed an aerial poisoning operation to eradicate possums in a target area of 1200 hectares of bush on the hill called Okatainga and its surrounds opposite the Karioi Pulp Mill. "Possum control is necessary to stop the spread of bovine tuberculosis, which is a serious threat to our export markets," said regional council destruction supervisor Dave McKinlay. The block covered parts of seven properties and the Ministry of Agriculture had identified it as a high risk area. The poison drop, planned for before Easter, had been delayed by unstable weather. At least three days of fine weather is needed as the pellets are easily dissolved by rain. However farmers needed to move stock on to the target area and the weather was likely to deteriorate so the operation could not be delayed any longer.

"In the end our hand was forced and we decided to go ahead on Monday 17 March," said Kevin Battersby, assistant destruction supervisor." To overcome the possum's natural suspicion the area was 'prefed', which involves giving the possums non-toxic Turnpage4

Possum poison

From page 3 baits so that they become used to them. The cereal and grain pellets are laced with cinnamon which the possums develop a taste for. They were spread at a rate of 1.8 kilograms per hectare. The toxic baits have the same basic ingredients but also contain .08% sodium mono fluoracetate (1080 poisonO and a green dye. The toxic pellets were spread at a rate of seven kilograms per hectare. Local pilot Rick Harding of Raetihi was responsible for the aerial spreading. A helicopter was used around the boundary of the area and on a small block nearby for greater accuracy. Care was taken to avoid a site sacred to local Maori. The remainder of the spreading was done with a fixed wing Fletcher aircraft. The effectiveness of the poison drops is determined by monitoring possum numbers before and after an operation. Flower pots containing non toxic baits are spaced at 50-80 metre intervals. The baits are

replenished over a number of days and the number of baits eaten noted. This enables a calculation to be made of the likely number of possums in the area. "Past success rates with aerial campaigns have been in the vicinity of 85-90%", said Mr. McKinlay, "We are hoping for similar results this time".