Early rust samples spark fears of epidemic (North/South, 12 August 2008)

Early rust samples analysed by the Cereal Rust Laboratory have sparked concerns that stripe rust, and possibly leaf rust, may hit for wheat crops across southern Queensland and northern and central western NSW this season.

Colin Wellings, University of Sydney plant pathologist said rust detection so early in the 2008 season should raise industry-wide concern and warned growers to plan for control strategies.

“One sample from Marombi wheat at Dunedoo, NSW was infected with leaf rust, and a sample of stripe rust was taken from Tobruk triticale at Young, NSW,” Dr Wellings said.

“This is a notably early occurrence for rust diseases in commercial fields.”

Growers support the Australian Cereal Rust Control Program through the Grains Research and Development Corporation (GRDC).

GRDC Manager Crop Protection Rohan Rainbow says current GRDC-supported trials show using fungicides at seeding for main season and late planted wheat provides early crop protection.

“Selection of rust-resistant varieties , teamed with control of the green bridge of volunteer plants over summer and,strategic fungicide use are the three clear strategies we need growers to take on board,” Dr Rainbow said.

“GRDC is a major investor in the fight against cereal rust and we are carefully monitoring rust threats both here and overseas.

“This issue should not be taken lightly as it has the potential to devastate the Australian grains industry.”

Dr Wellings said a wet summer contributed to survival of rust pathogens and, depending on seasonal conditions for crop growth in 2008, he expects rusts will be widespread and potentially damaging.

“Crops now well established from early seeding will need to be inspected immediately.”

He says foliar fungicides combined with strategic grazing should be considered, with due attention paid to withholding periods.

“Varieties known to be vulnerable to rust will need to be monitored carefully throughout the season.

“While the WA Yr17 pathotype has not been detected in the current
season, we expect it to survive and reemerge.

“Varieties now vulnerable to this pathotype should be carefully monitored and foliar
fungicides employed when appropriate.”

To have plant samples analysed, mail in paper envelopes (without plastic wrapping or plastic-lined packages) to: Australian Cereal Rust Survey, Plant Breeding Institute, Private Bag 11, Camden NSW 2570 or phone (02) 9351 8800.

For more information, visit www.grdc.com.au/rustlinks

GRDC Code:US00039

Region North, South