Determination of Alternaria Leaf Spot incidence within canola cultivars

Alternaria Leaf Spot is a fungal pathogen which has shown increasing prevalence within the Australian Canola industry, causing yield reductions of up to 1t/ha. It is estimated that severe infections during high risk years can cause yield losses of 30% or more within Australia, whilst countries overseas have seen yield losses of up to 70% due to Alternaria.

Infected pods can also reduce the oil content of grain, with reductions as large as 14-32% being observed within crops. The severity and incidence of infections appear to be influenced by rainfall, temperature and humidity. In the Australian Canola growing regions, at least 10 species of Alternaria have been proven to be virulent towards Australian Canola cultivars, with two species (A. Brassicae & A. Japonica) displaying a high level of virulence towards cultivated lines.

Despite the estimated yield losses caused by Alternaria alone, there is limited data for Australian canola growing regions which highlights actual losses. The aim of this investment is to determine the prevalence of Alternaria, and the potential yield losses associated with infection.