Fungus disease attacks forests in Taupo area

Taupo Times, Volume XII, Issue 52, 6 July 1965, Page 7

Fungus disease attacks forests in Taupo area

Ihe New Zealand Forest bervice is keeping a close watch on a new fungus disease which has been discovered in a number of pine forests . in the Rotorua-Taupo area. It was for this reason that disease-free plants were brought to Taupo from Nelson recently.

The disease, Dothistroina pini, was first noticed in New Zealand in 1962. It has been found in Kaingaroa Forest, in forests owned by New Zealand Forest Products and other private forests around the Tokoroa-Putaruru areas, at Karioi (near Ohakune) and in Te Wera forest, near Stratford. Although the disease has not as yet caused much damage in New Zealand, it

has had serious consequences in radiata pine plantations of East Africa, where large scale spraying trials have been carried out to try to combat it. The New Zealand outl break is under the close istudy of a Forest Research Institute forest pathologist, Mr J. S. Gilmour, and Dr G. Whyte, silviculturist, with a team of technicians. Forest biology observers throughout New Zealand are keeping a close lookout for signs of n e w outbreaks. Because no infestations have been found in the South to date, the Forest Service has decided not to allow any of its exotic tree stocks to be taken to the South Island. Big quantities of young pine trees have been air freighted and railed from Nelson to the North Island, for winter planting in areas which are still thought to be free of Dothistroma pini. Horticulturists and members of the N.Z. Farm Forestry Association have been alerted to keep a wratch out for the disease, So far the disease has been found mainly in radiata and ponderosa pine. The Forest Research Institute is adopting a "wait and study" policy on the implications of the outbreak at present. There have been periodic alarms in the past over disease or insect outbeaks, but

in most instances the outbreaks subsided naturally before reaching disaster proportions. Scientists feel that any "panic" at present could be both costly and unnecessary. Dothistroma pini can be effectively controlled with copper sprays applied by air, but it is felt the cost of such a largescale operation is not war- . ranted at present. Mr Gilmour said the disease had not killed many radiata pines so .far, but there were some pockets of very severe defoliation in Kaingaroa and the forests around Putaruru-Tokoroa. The disease, a needle cast fungus, can be recognised by the fc>wer foliage of pine trees dying off, with the needle^ having a brick red coloured narrow banding across them, while the remaining parts may be greenish or pale brown. The narrow bands of infection (from i to inch) carry several to multiple minute black dots..