Department research officer Moin Salam said the blackleg disease model, known as Blackleg Sporacle, could assist in predicting the release of blackleg spores from old canola residue, based on climatic conditions.

“A disease model like this gives growers confidence to seed canola in low risk situations without applying fungicide,” Dr Salam said.

“This year, the lack of summer rain in WA and the good April rains have delayed the priming of canola residue to release blackleg spores until after the bulk of the canola crop will have emerged in most of the wheatbelt.”

He said this means that seedlings are likely to escape the bulk of the blackleg spore release when they were most susceptible.

Dr Salam said that in the past early summer rain in some districts had led to the release of spores at the same time as crop emergence – the most critical stage for canola to be inflected with the disease.

Department pathologist Ravjit Khangura said, "By timing crop emergence to avoid the bulk of the blackleg spore release from old residues, canola growers can reduce the impact of the disease on the crop substantially.”

Dr Khangura cautioned that although Sporacle is an aid in predicting blackleg disease risk based on climatic conditions, it did depend on:

• Proximity to previous canola crops.

• Timing of canola crop emergence.

“If growers address all three of these factors, they will be well on the way to managing blackleg in canola,” she said.

SOURCE: WA Department of Agriculture and Food.