Chickpea checks a must

All chickpea crops in Victoria and South Australia will need to be closely monitored this year for Ascochyta blight, AB, infection.

South Australian Research and Development Institute pulse pathology principal research scientist Dr Jenny Davidson said all varieties were now rated as either susceptible to moderately susceptible to infection.

She said a virulence change in the AB pathogen of chickpeas had occurred; with severe AB infection detected in previously resistant chickpea varieties across both states in 2015 and 2016.

Dr Davidson said while AB infection was more severe in high and medium rain zones, effective disease control strategies were also required in low rain regions.

“This is because severe disease outbreaks could occur in these environments during wet seasons, as was the case in 2016,” she said.

“Moderately susceptible varieties will generally require three to four strategic fungicide sprays ahead of rain, offering two to three weeks of protection, starting at six to eight weeks post-sowing.

“Susceptible varieties will require regular fungicide sprays every two to three weeks throughout the growing season in front of rain.”

Dr Davidson said because the pods of all commercial varieties were susceptible to AB, they would also require fungicide sprays during pod setting ahead of rain fronts to protect the pods from seed staining and seed abortion.

Dr Davidson’s research is supported by the Grains Research and Development Corporation.

Agriculture Victoria pulse agronomist Dr Jason Brand said growers also needed to factor into their 2017 management strategies the impact of early sowing following recent rain throughout South Australia and Victoria, as rapid early growth could lead to a greater risk of AB infection.

Dr Brand, leader of the GRDC Southern Pulse Agronomy program investment, reported that while outbreaks of AB were significant in Victorian chickpea trials last year, crops generally recovered well from the disease as soon as conditions dried out.

He said the AB pathogen would survive on stubble and organic matter for many years, so growers needed to observe a minimum three-year rotation between chickpeas in the same paddock, and avoid planting next to the previous year’s chickpea stubble.

Dr Brand said it was imperative all chickpea seed was treated with a thiram-based fungicide to prevent seed transmission of AB to emerging seedlings.

He said ongoing research into pulse diseases in the southern cropping region would include further assessment of the impact of AB on seed quality.