Be alert but not alarmed about stripe rust

Stripe rust has been detected in wheat crops for the first time this season.

Richard Daniel of the Northern Grower Alliance alerted Queensland Department of Primary Industries and Fisheries (DPI&F) plant pathologists of the detection by agronomists in three locations in northern New South Wales - between Cryon and Walgett, near Gurley, and north-west of Moree.

Samples from each site are being sent to the Winter Cereals Rust Control Program at Cobbitty for confirmation.

DPI&F plant pathologist Peter Wilkinson said although the detections had all been in northern NSW, it was likely that stripe rust would spread, and Queensland farmers should be on the lookout.

“Currently conditions in the region are suitable for the disease to develop,” Mr Wilkinson said.

“Stripe rust spores need high humidity in the plant canopy for 4-6 hours with temperatures of 10-15 degrees to infect the crop successfully. Pustules are seen about 14 days later,” he said.

Mr Wilkinson said, “Queensland growers with susceptible varieties with a rating of 5 or below should check their paddocks for the disease. It is important they look under the crop canopy, as the disease often develops low down the crop and is difficult to find in the early stages.

“Foliar fungicides can give very good control but timing is critical to give maximum benefit. A single application when the flag leaf is just emerged will usually give the best economic response from a single application.

“The severity and economic importance of the disease will depend on the earliness of development, the weather, and the extent of susceptible cultivars,” he said.

Mr Wilkinson said the Cereal Diseases: The ute guide contained colour images of all the major diseases in wheat, barley and oats and was available for $20 plus postage and handling from the Grains Research and Development Corporation (www.grdc.com.au/bookshop, or 02 6272 5525).

“There is stripe rust information and images on the DPI&F (http://www2.dpi.qld.gov.au/fieldcrops/17139.html), or contact the DPI&F (13 25 23) for a copy of a stripe rust brochure,” he said.