Ministry attacks potato wart

Press, 6 July 1977, Page 13

Ministry attacks potato wart

Wellington reporter All sites known to be infested with potato wart disease fungus, one of the most serious scourges of New Zealand’s potato crop, have been fumigated during the last two summers by the Ministry of Agriculture. The soil-borne fungus causes warty outgrowths on potato tubers and, according to the Ministry’s chief advisory officer (plant health) (Mr J. D. Currie) poses a big threat to New Zealand’s horticultural exports. The disease was discovered in 1970, but a joint survey with the D.S.I.R. had shown it to be confined to 17 home gardens around Invercargill.

Mr Currie said that a ban had been placed on transportation of potatoes grown within 15km (10 miles) of Invercargill, to avoid

spreading the fungus. If allowed to spread, the disease could have caused New Zealand to be shut out of overseas horticultural markets.

Australia, Canada, and most of the United States were free from the disease and would not import potentially soil-bearing plant material from areas where the potato wart occurred. A D.5.1.R.-approved fumigant had been used on infested plots, which were first cleared of vegetation, rotary-hoed to a depth of 50cm (20 in.) and covered with heavy polythene. Untreated spores could survive up to 30 years in the soil. Mr Currie said that the insidious nature of the disease meant that further outbreaks were still possible, and a careful watch should be kept out for any unusual symptoms on potato plants.