Trap results suggest heightened barley disease risk
Date: 27 May 2014
Grain growers in Western Australia’s southern cropping regions are advised that there is a heightened risk of foliar fungal diseases infecting barley crops this season.
Department of Agriculture and Food (DAFWA) researcher Kith Jayasena said DAFWA spore trapping work supported by the Grains Research and Development Corporation (GRDC) had detected spores in mid-may of leaf rust, net blotch, spot blotch/root rot, scald and powdery mildew.
“Despite a very dry summer and early autumn, the spore trap results and disease findings on crop regrowth are an early warning sign that these diseases are likely to infect 2014 barley crops in the southern grainbelt,” he said.
“Past observations in this region have shown that crop disease symptoms can appear in crops two to six weeks after spores are found in traps.”
Dr Jayasena said the spore traps were located at South Stirling in the lower Great Southern region but other areas of the grainbelt, particularly higher rainfall areas, might also have a heightened disease risk.
“I encourage growers to monitor the early development of crops for leaf disease symptoms and to consider using a registered foliar fungicide if the variety is susceptible to the diseases found,” he said.
“A second spray may be necessary. Whenever possible, rotate fungicides with different actives to reduce the development of fungicide resistant pathogen populations.”
Dr Jayasena said avoiding seeding barley on barley; choosing varieties with good disease resistance; using registered seed dressings or in-furrow fungicides; and avoiding a high seeding rate were seeding strategies that could help minimise the risks.
Growers who had completed seeding programs could reduce the risk of crop losses by:
- Destroying barley volunteers in non-cropping paddocks, laneways, crop boundaries and fencelines;
- Avoiding high nitrogen rates early in the season which can generate a bigger crop canopy, favourable to disease development;
- Applying potassium fertiliser to crops deficient in the nutrient six to eight weeks after crop emergence;
- Using foliar fungicides. A list of registered products is available by searching ‘registered foliar fungicides’ on the DAFWA website www.agric.wa.gov.au
Dr Jayasena said GRDC supported spore trap experiments were underway which aimed to finetune recommendations to growers about the optimum timing for foliar fungicide application in any given season.
Information about identifying and managing foliar diseases is available at www.agric.wa.gov.au/cropdisease
Information about GRDC funded fungal disease research is contained in a GRDC Cereal Foliar Fungal Diseases Supplement available at www.grdc.com.au/GCS110
Kith Jayasena, DAFWA
08 9892 8477, 0407 081 388
GRDC Project Code DAW00229