THIS season is shaping up to be a big one for canola growers in central and southern NSW, but behind the rosy picture lies a challenge in keeping the fungal disease blackleg under control. NSW Department of Primary Industries (NSW DPI) pulses and oilseeds technical specialist, Don McCaffery, said excellent yields last season, buoyant prices and good subsoil moisture levels are behind the optimistic outlook for growers. “About 395,000 hectares of canola was grown in NSW in 2011, leaving a lot of canola stubble hosting the blackleg disease pathogen,” he said. “With another large planting predicted for this season, canola growers will have to keep on top of blackleg to ensure the disease does not economically affect yields. “Fortunately, growers can take a number of steps to reduce blackleg severity and the risk of yield loss.” Mr McCaffery said an integrated and planned management approach is required, starting with paddock selection. “The distance this year’s crop is sown from last season’s stubble is important in determining the disease pressure from blackleg,” he said. “Planting at least 500 metres from last year’s stubble will significantly reduce the impact of blackleg. “Growers should not sow canola on last year’s canola stubble as it could result in total crop loss. “This practice would pose a huge risk to the industry as the blackleg disease might not only overcome the resistance of the canola sown, but also a large number of varieties that have similar resistance genes. “Further reductions can be achieved by selecting varieties with good blackleg resistance, sowing early and using fungicide seed treatments and fungicide amended fertiliser.” All factors influencing blackleg are brought together in an easy to follow decision guide called the Blackleg Risk Assessor, available at www.grdc.com.au. “The Blackleg Risk Assessor enables growers and advisers to assess the risk of yield loss from blackleg down to the individual paddock level,” Mr McCaffery said. “It is important that canola growers start planning their pre-sowing management strategies to prevent significant crop losses this year and avoid risking the industry’s long-term future.”
