[Weekly Times, 25 Nov 2009, Page: 96] Summer thunderstorms can cause difficulties for grain growers who need to spray for summer weeds. But it can also cause difficulties for horticulturalists, apiarists and other grain growers if the herbicide drifts on to other crops. Department of Primary Industries chemical expert Alan Roberts said a vast amount of damage was done in 2004-05 when herbicide drifted from broadacre farms to horticultural farms near the Murray River.
Mr Roberts said DPI had worked with both groups to understand the issues and run courses in spray drift. He said there had been no major issues since, but each summer he worried about thunderstorms and weed-spraying. "Perhaps my concerns have been misplaced," Mr Roberts said. Alan Roberts "We do get some issues, but not as many as before." Mr Roberts said rain in Bendigo last month would have led to extensive spraying of fallow paddocks with broadleaf herbicides. "Everyone is conscious of the need to preserve water in the soil," he said. Mr Roberts said he had heard reports of droplets drifting 500m into another crop. "It's an issue for everyone" he said. "It can drift from vines into pasture or from livestock properties into vines." Mr Roberts said when he ran workshops along the river after the 2005 incident, attendees were surprised at the potential impact of their spraying. "They did not know how it affected other properties," Mr Roberts said.
He said advances in tractor technology, while making hours on the tractor more comfortable, made it difficult for farmers to monitor conditions. "It's easy to sit in an airconditioned cab with a large boomspray with autosteer," Mr Roberts said. "Those are very isolated conditions and the farmer might not know if the conditions have changed outside the cab." Mr Roberts said that, in a recent case near Horsham, conditions were fine for spraying when the farmer started, but a change in conditions pushed the spray over houses, without the farmer being aware of it.
He said internal drift, where the herbicide drifts within the farm on to a nontarget paddock, was also a big problem. Mr Roberts said many horticulture crops, including almonds and olives, were grown in areas alongside broadacre crops. "There are lots of places where there are lots of things growing over summer," Mr Roberts said.
He said insecticide spray drift could also cause problems. "The increase in horticulture means more pollination for bees and people using insecticide, it may not occur to them that bees are in the vicinity," Mr Roberts said. "It will kill them." He said a lot of work had been done by beekeepers to be easily found by farmers. "They put their mobile phone numbers on the boxes so the person doing the spraying can give them a call and to discuss the situation," he said.
More information is available from chemical standards officers at the DPI on 136 186.