Western Australian field pea growers will soon have access to an advanced version of Blackspot Manager - the modelling tool to help minimise crop damage from blackspot.

The Blackspot Manager, developed by the Department of Agriculture, Western Australia, forecasts the onset and progression of spore dispersal from infected field pea stubble, and the incidence and frequency of ascospores during the growing season.

The model estimates the probability of a blackspot infection occurring taking account of the proximity to the previous season’s field pea stubble, rainfall, wind speed and wind direction.

Department researcher Moin Salam said windblown spores were the key source of blackspot infection in field pea crops grown in Western Australia. 

Dr Salam said the new Blackspot Manager examined the regional spread of blackspot, and had been validated since 2000 in the Geraldton, Northam, Pingrup and Scaddan districts. 

He said the spread module was in its third year of validation with growers from the Pulse Association South East (PASE) at Scaddan. 

“Predicting ascospore maturity helps growers choose a suitable sowing time to minimise the risk of blackspot disease,” Dr Salam said. 

“With the Blackspot Manager being able to predict the disease pressure on a paddock, as well as across a region, growers can use the model to select and rotate paddocks for field peas.

“Not only does the model analyse their property, but also takes account of neighbouring cropping programs.”

Dr Salam said to manage blackspot in field peas it was recommended to delay sowing until close to the end of the sowing program to avoid the peak level of ascospores falling on the newly emerged crop, reducing the level of disease.  However, delayed sowing could reduce potential yield, especially in the low rainfall areas of WA.

Dr Salam said the Blackspot Manager model had been developed further to quantify yield losses with delayed sowing. 

“The model now predicts for each region the potential yield for a given time of sowing, the yield loss due to delayed sowing and the yield loss due to blackspot disease. The yield loss module is being validated during the 2004 season in different regions of Western Australia,” he said.