The Australian Pesticides and Veterinary Medicines Authority (APVMA) has issued a permit for the use of triadimefon in-furrow to control stripe rust on wheat.

The permit follows ongoing risk assessment for stripe rust undertaken by the West Australian Department of Agriculture in the lead up to seeding.

Department manager of cropping systems research David Bowran said the current assessment follows widespread rain in late March. Recent thunderstorm activity resulted in 40-60mm falls throughout many areas, particularly in the central and southern wheat belt.

"These areas, already at risk from stem, stripe and leaf rust infections this season, will have increased 'green bridge' risk as a consequence of these rains," Dr Bowran said.

"A ‘green bridge’ occurs when self-sown cereals survive over summer/autumn and provide a host for rust diseases. If the plants persist, they allow the development of cereal rusts such as stripe rust, ahead of the cropping season," he said.

Dr Bowran said that there was a range of seeding fungicide options available to help manage stripe rust in susceptible varieties, including seed treatments and in-furrow fertiliser treatments.

"The permit extends the available options for in-furrow fertiliser treatments for this season's seeding period and is effective to 31 July 2003," Dr Bowran said.

"The permit has been issued to ensure that demand for in-furrow products that give longer wheat seedling protection, including those suitable for DAP type fertilisers and fertiliser used at low application rates, can be met under increased likelihood of rust incidence," he said.

The permit applies to fungicides containing the active ingredient triadimefon, for application onto fertiliser prior to sowing. Application rates on fertiliser equivalent to 200 g/ha of a 500 g/kg triadimefon powder formulation or 800 mL/ha of a 125 g/L triadimefon liquid formulation are covered by the permit.