Early application key to disease control

Countryman

Research has found applying fungicide early can be invaluable for controlling wheat leaf spot disease infections and, more importantly, it can be profitable in wheat-on-wheat cropping.

Department of Agriculture and Food research officer Ciara Beard said traditionally many growers applied foliar fungicides and herbicides to crops at early growth stages, prior to stem extension.

"Department and Grains Research and Development Corporation (GRDC)-funded trials were conducted across the central and northern Wheatbelt in 2010 and 2011 to determine appropriate times to apply foliar fungicide, with the view of gaining the best economic outcome," Ms Beard said.

"We found when a wheat variety susceptible to yellow spot or stagonospora (septoria) nodorum blotch was grown on wheat stubble, these diseases were likely to be seen before stem extension.

"In this situation, trials showed applying a fungicide at or before stem extension could be effective and provide good economic returns."

Disease development and fungicide response is determined by the presence of the disease in the crop and the occurrence of disease-favourable conditions following application.

"In 75 per cent of trials, we found yields increased on average by 11 per cent and grain quality also improved," Ms Beard said.

"Application at first node growth stage proved to be the most reliable timing in terms of profitability.

"Fungicide applied at seedling or tillering stage reduced early infection, but often gave a shorter duration of disease protection and was less likely to be as profitable as application at the first node stage.

"We have also had success with some in-furrow fungicides providing wheat leaf spot disease control, and although they are not registered yet, they may be another option available to growers in the future."

Other trials conducted by Ms Beard in 2010 and 2011 found that a nitrogen-deficient wheat crop was more vulnerable to infection by wheat leaf spot diseases.

"This highlights the importance of having adequate nitrogen levels and fungicide applications for optimal leaf spot disease control, particularly in susceptible wheat varieties," Ms Beard said.

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Details of the research findings will be presented at the Agribusiness Crop Updates on February 28 and 29. To register. visit <a rel="nofollow" href="http://www.agric.wa.gov.au/">www.agric.wa.gov.au/ </a>

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