GREEN bridges created by self-sown wheat and triticale could spell rust for this cropping season.

The importance of the green bridge was evident last year when rust pathogens survived over summer on self-sown plants.

Research scientist Colin Wellings said growers needed to proactively plan for rust control this year.

This included protection for early emerging crops by eliminating the green bridge and using fungicide on seed or fertiliser.

Dr Wellings, of the University of Sydney's plant breeding institute, said fertiliser coatings and granulated formulations had protected early-sown crops.

He said main-season crops had benefited from fungicide applications up to growth stage 39 (stem elongation).

Dr Wellings said with-holding periods needed to be considered for grazing cereals sown with seed or fertiliser fungicide.

"Know what to expect with the disease response of each variety," he said.

"Keep abreast of district and regional stripe rust activity and be prepared to act."

Speaking at a Grains Research and Development Corporation update at Wagga Wagga in southern NSW, Dr Wellings said grazing management could be an effective strategy to reduce an early burden of stripe rust.

Growers could also consider tank-mixing fungicide with broadleaf herbicide post "lock-up".

Three stripe rust pathotypes have infected crops in eastern Australia in recent years.

The Jackie pathotype dominated early last year with the WA Yr17 staging a comeback in late spring.

Between 2003 and last year, Dr Wellings received 3200 rust samples for testing.

He said WA Yr17 had jumped from 15 per cent of infections in 2008 to more than 30 per cent last year.

The Jackie Yr27 pathotype was not found last year.

"Wheats carrying Yr27 performed well to stripe rust during the season," Dr Wellings said.

"Wherever possible, growers are encouraged to select varieties that show resistant, moderately resistant or moderately susceptible responses.

"Crusader, gregory, ventura and tobruk dominated the varieties in the stripe-rust epidemic of last year."

Dr Wellings said this year's weak spots were crusader, elison, gregory, lincoln, marombi, ventura, wedgetail and tobruk, while ruby was vulnerable.