Rohan Rainbow, Grains Research and Development Corporation manager for crop protection, says growers who have planted rust-susceptible varieties must carefully monitor crops and plan ahead for the possibility they may have to spray for rust.

The GRDC-supported University of Sydney Cereal Rust Laboratory (CRL) at Camden, NSW, has reported 64 rust samples for July, compared to just six in July 2007.

Colin Wellings, NSW Department of Primary Industries (NSW DPI) plant pathologist based at CRL, says the 10-fold increase clearly indicates that the early occurrence and magnitude of sample numbers in the current season is very unusual, and could potentially lead to a serious epidemic in spring.

Early samples in 2008 that were processed by the Cereal Rust Laboratory have revealed pathotypes including the 'WA' pathotype, code 134 E16 A+ at Dubbo, Cumnock and Warren, NSW.

The virulent pathotype, 'WA Yr17' has been found at Cumnock and Young, NSW in the dual purpose Marombi wheat variety.

Jackie pathotype has been found in triticale in Tobruk (at Young and Manildra, NSW), Breakwell (Young, NSW) and Jackie (Goulburn, NSW).

"It is too early to gauge relative frequencies of these pathotypes, although it is clear that all three are currently present in a range of crops in NSW south from the Warren/Dubbo region," Dr Wellings said.

Samples received that are currently under study range from southern Queensland to northern Victoria.

* For more information on strategic rust control, visit www.grdc.com.au/rustlinks