PLANT DISEASES ARE STILL BEING INTRODUCED

Bay of Plenty Beacon, Volume 14, Issue 59, 4 November 1949, Page 7

PLANT DISEASES ARE STILL BEING INTRODUCED

Fruit trees in the Bay of Plenty have felt the affect of some / of the one hundred new plant diseases that have been introduced into New Zealand- in the past ten years. Despite efforts to combat these diseases they have spread quickly and now the Department of Agriculture, which investigates many of them, 1 is making a complete overhaul of its plant quarantine system. Developments leading up to the decision for more effective quarantine against the causes of plant diseases were outlined by Mr L. W, Tiller, B.Sc., of the Department of Scientific and Industrial Research. He noted the disastrous introduction of the white butterfly, the Australian termite which was doing much damage to buildings at Auckland, and the European wasp, now spreading rapidly in the northern part of the North Island. Vegetable Bug Now came the green vegetable bug. It was prevalent in the Leeward Islands and in Australia, and also occurred in the South Pacific Islands. It was half-an-inch long, shaped like a -shield, and of a very Vivid green. After the insect’s appearance in New Zealand, the problem it raised was referred to the Nelson entomological station, a joint undertaking by the D.S.I.R. and the Cawthron Institute of which Dr D. Miller is tlje head. From his knowledge of the insect, Dr Miller was import parasites from Australia' These were eventually shipped to North Auckland, where they appear to be doing successfully. Speaking generally, said Mr Miller, the potentiality for good or evil insect, fungus, bacterium and virus in New Zealand was understood, save, perhaps, in the case of thh manuk& scale. This disease attacked the scrub species of manuka and would kill off these plants in an area in five or six years.

Caused Erosion Foresters and soil conservators contended that this tended to erosion and, as this species of manuka was the natural shelter for seedling native trees, its destruction might prevent re-afforestation. On the other hand, farmers saw in the scale the prevention of encroachment by manuka on their property, and were so satisfied of its beneficial activity that those with land on which the scale was pre- / sent supplied it to farmers who were without it. There the issue rests.