Pine disease bad this year

Press, Volume CXI, Issue 32700, 1 September 1971, Page 2

Pine disease bad this year

(N.Z. Press Association) WELLINGTON, Aug. 31. Warm, humid weather from late summer and through the winter has helped a parasitic fungus infect large areas of pine forest

A forester at the Forest Service’s head office, Mr I. P. Armitage, said today that the favourable weather was one reason why about 65,000 acres of radiata pine would be sprayed this year. Spraying would take place during November and December, mainly in the central North Island. The department was still deciding how many acres should be sprayed.

Last year only 25,000 acres was sprayed. In 1967, when the fungus Infection first became bad, 80,000 ■acres was sprayed. The fungus, known as the needle-cast fungus, is Dothlstroma pin!. It was accidentally imported, possibly from Kenya, in the late 1950 s or early 19605, Mr Armitage said.

A needle of a radiata pine tree attacked by the fungus first showed a small

red band and later turned yellow, then brown, and died. Infected trees lost many of their needles. Radiata pine trees were susceptible to infection between the ages of two and 18 yean, Mr Armitage said.

There were extensive areas of susceptible young trees because the rate of planting had increased in the last few years, he said. These areas should be sprayed this year.

There was no evidence that the fungus killed radiata pine, but it seriously reduced growth rate. Both the ponderosa and Corsican pines died from the disease, and the Forest Service no longer planted them, Mr Armitage said.

The needle-cast fungus was established in the North Island, Nelson and Westland.

“We are doing all we possibly can, through forest hygiene, to stop the disease being spread to Canterbury and Southland,” Mr Armitage said. The Forest Service was also doing research into the biology and control of the fungus.