Wet spring sparks cereal disease warning
Cereal growers are being warned to act now to counter the high disease risks following last year’s wet spring.
As the sowing season approaches, croppers face greater disease loads on their heavy stubbles and from crop regrowth after summer storms.
Agriculture Victoria’s senior plant pathologist Grant Hollaway urged growers to control summer weeds and volunteer crops and choose their varieties carefully for the coming season to reduce the disease threat.
Dr Hollaway said many cereal diseases should be watched out for this season.
‘‘Disease pressures in Victoria’s 2016 cereal crops were high during the wettest spring in 25 years,’’ he said.
‘‘Yellow leaf spot in wheat, which favours damp conditions, was widespread and severe, with 20 per cent losses in susceptible variety trials. Resistant varieties reported less than six per cent losses.’’
Similar losses were recorded from spot form of net blotch in barley.
Dr Hollaway said rusts were prevalent in wheat, although development was slowed by the cooler spring.
‘‘Cereal diseases will need active management this season following carry-over of high levels of inoculum on stubble and the green bridge after last year’s wet conditions,’’ he said. He urged growers to consider: ■ Variety choice (consult a current disease guide).
■ Paddock selection (consider paddock history and take a soil test if unsure about root disease risk).
■ The green bridge (rust carry over on cereal volunteers).
■ Putting in place a fungicide plan for the control of potential disease threats.
Dr Hollaway said septoria had continued to be important in high rainfall zones, with surveys last year showing it was now also present at low levels in the Wimmera.
‘‘A PreDicta B test prior to planting will identify paddocks at risk to enable appropriate management to be implemented,’’ Dr Hollaway said.
He also encouraged growers to manage the risks for bunts and smuts.
‘‘Seed should be treated every year as bunt and smut can increase rapidly, resulting in unsaleable grain.’’ ■ The annual Agriculture Victoria Cereal Disease Guide will be launched at the GRDC advisers’ update at Bendigo later this month.