NEED FOR CARE WITH SPRAYS

Press, Volume CXV, Issue 33774, 21 February 1975, Page 10

NEED FOR CARE WITH SPRAYS

Farmers spraying brassica crops for weeds in the next few weeks should be conscious of the long-term effects of some weedicides, according to Mr F. C. Allen, district scientist (weed research), with the Ministry of Agriculture and Fisheries. He said several instances of herbicide damage to pea and potato crops were seen again in the past year, and in most cases it was due to spraying a brassica crop for weeds in the same field in the previous three years. In a few cases irrigation water contaminated with herbicides had been the cause. Mr Allen said the very soil stable chemical, picloram, which is a component of some products used for weed control in brassicas, as well as in some shrub weed herbicides, had been the cause of the damage in most cases. “While products containing picloram are perfectly

safe for their specialised use, the message is clear,” said Mr Allen. “Do not use picloram-based products to spray weeds in brassicas if you are contemplating growing peas, potatoes or lucerne in the same paddock within the next three years. “With shrub weeds, do not spray race or stream banks during periods when water is likely to be used for irrigation.” Mr Allen said that there was also a danger of spillage or tank washings getting into races, and then getting on to paddocks by surface run-off. "You may not be affected, but your neighbours will be.” Weed control in brassicas at this stage was a difficult one, he said, and there was not much a farmer could spray with except piclorambased products. “But farmers must be aware of the long term effects in the soil of this chemical and the damage which can result to peas, potatoes, lucerne, and base their decisions on this,” said Mr Allen.