Australia
November 26, 2010

Grain growers in the Western District of Victoria are advised to remain on alert for the potential development of stem rust in late maturing wheat crops.

Department of Primary Industries senior grains pathologist, Dr Grant Hollaway, says susceptible varieties should be closely monitored to assist with early detection and management.

“Should stem rust be detected in susceptible crops that are in the milky growth stage or earlier, growers should consider applying a fungicide as soon as possible,” Dr Hollaway advises.

“Stem rust is potentially a very damaging disease in wheat, but losses can be minimised with the timely application of foliar fungicides. If stem rust is detected in a wheat crop growers should discuss control options with their agronomist. Growers need to consider with-holding periods when selecting foliar fungicides.”

Dr Hollaway, whose work is supported by the Grains Research and Development Corporation (GRDC), says that if stem rust appears earlier in the season it can cause large yield losses, but its development at this time of the year is more likely to impact on grain quality.

“Unchecked stem rust development in late maturing crops could also assist pathogen carry over. The carry over of stem rust on wheat from one season to the next is greatest during years with wet summers and autumns.

Wheat varieties susceptible to stem rust growing as volunteers during wet summers enable inoculum levels to build up and these plants can become heavily infected with rust in the autumn and provide a source of rust for the new season’s wheat crop. If these conditions are followed by a mild winter and a warm wet spring, the chances of a stem rust epidemic are high,” he says.

Growers are urged to sow varieties with resistance to rust to reduce the likelihood of disease outbreaks in future seasons. Comprehensive rust management information is available from the GRDC online service at www.grdc.com.au/rustlinks.

On behalf of growers and the Australian Government, the GRDC supports research into rust management through the Australian Cereal Rust Control Program.

Website: http://www.grdc.com.au

Published: November 26, 2010