The detection of stem rust on volunteer cereals on the south coast has highlighted the need for grain growers to assess their green bridge rust risk in preparation for the 2004 cropping season.

With significant summer rain in parts of the wheatbelt, the Western Australia Department of Agriculture has identified mid March as the time to identify risk of local green bridge carryover in their area. The Department has declared March 17^th Green Bridge Day to coincide with St Patrick's day.

A green bridge exists when self-sown cereals survive over the summer months, providing a host for rust diseases.  Rusts have difficulty surviving in the absence of green hosts over summer.

Dr Loughman said that after significant rains in early January and mid February, volunteer cereals had become well established along the south coast from Mt Barker to Esperance and through the eastern fringe of the wheatbelt from Southern Cross to Hyden.

Reports of volunteer cereals between Ongerup and Jacup indicate numerous paddocks with self-sown wheat or barley at grain fill.  In some cases stem rust was already evident and starting to build up.

Dr Loughman said that rust risk was significantly greater in districts where green bridge paddocks persisted into autumn because of potential to overlap with sown crops.

"Now is a good time to check if paddocks are supporting green bridge cereals so that they can be sprayed or grazed out and other aspects of rust management, including variety and fungicide options can be reviewed in the lead up to planting.

Growers throughout the wheatbelt, but particularly those in the Plantagenet, Albany, Gnowangerup, Jerramungup, Ravensthorpe, Esperance, Westonia, Yilgarn, Narembeen, Kondinin, Kulin and Lake Grace Shires, are asked to inspect last year's cereal paddocks for green bridge cereals and assess their risk and risk management strategies going into 2004.

Green bridge paddock inspections timed around St Patrick's day will highlight areas where potential exists for early rust occurrence and give farmers opportunities to destroy the green bridge and make final seasonal preparations for management of rust diseases including stem, stripe and leaf rusts," Dr Loughman said.

Growers seeking further information on rust management and advice on control of volunteer cereals can contact their local office of the Department of Agriculture.