Canola growers will be budgeting to defend their crops against sclerotinia stem rot this year after experiencing the worst season on record for the fungal disease.
Department of Agriculture and Food research officer Ravjit Khangura will provide an overview of last season and advice on what growers can do this year at the 2014 Agribusiness Crop Updates on 24-25 February in Perth.
Dr Khangura said sclerotinia cost Western Australian canola growers $59 million last year in yield losses alone.
Infection rates averaged 28 per cent of plants among 86 surveyed canola crops from 2014. This was twice the rate of previous seasonal surveys.
“That equates to yield losses of 0.3 to 1 tonne per hectare, however, we don’t yet know what the impact on oil content was.”
Dr Khangura said climate conditions created a ‘perfect storm’ for sclerotinia across the State in 2013.
“Wet and humid conditions allowed a build-up of inoculum, resulting in a spore release at flowering time, while conducive conditions post infection favoured disease development, which is why the disease was more aggressive than previous years,” she said.
Dr Khangura said while the dry summer would have no impact on the disease prevalence this season, she urged growers – especially those in high and medium rainfall areas – to budget for extra fungicide.
However, she warned growers that while Prosaro® was an effective fungicide for both sclerotinia and blackleg, one application would not treat both.
“You cannot kill both diseases with one shot, as fungicide won’t control an established disease,” Dr Khangura said.
“Department trials in 2013 showed the most effective treatment for sclerotinia was to apply 450 millilitres per hectare when crop stage was at 40-50 per cent bloom – even a follow up application three weeks later at the same rate was also effective.
“A well timed single spray resulted in an increase in seed yield of 29 per cent compared with untreated plots and the best gross margin of $102 per hectare.”
The department will continue research this year to further refine the use of Prosaro® to control sclerotinia.
The department is also developing a forecasting system using the epidemiological data collected over the last four years for predicting the risk of sclerotinia stem rot and this will help growers in making decisions regarding fungicide sprays. It is also working on other tools to assist growers to best control sclerotinia and optimise crop profitability.
Media contact: Dionne Tindale/Lisa Bertram, media liaison +61 (0)8 9368 3937