Self-sown wheat north-east of Mukinbudin being sprayed out recently to reduce the risk of rust diseases transferring to young crops.

Advanced growth of self-sown cereals throughout the far eastern wheat belt has highlighted the unusual nature of the 2005 growing season and posed the question – when will rust infections occur this year?

Paddock inspections in the eastern wheatbelt have revealed extensive areas of heading wheat that germinated on late March rains and has been sustained by ideal seasonal conditions.

No rust was apparent when paddocks were recently inspected by Department Officers, which is good news for young crops just establishing in the region. 

However the advanced self-sown cereals pose an ongoing risk to young developing crops, as uncontrolled early re-growth is likely to develop rust.

Following the early outbreak of stripe rust in 2004, rust risk diminished sharply over summer with very dry conditions throughout the wheat belt from December to March.  Extensive re-greening, particularly in the far in the eastern wheat belt, occurred with March and April rains and there are now paddocks carrying heavy stands of self-sown wheat from that time.

“We know that rust survives from year to year at very low levels and that the rust build-up re-commences with available green plants, so paddocks that self-sowed in March/April provide early start-up opportunities for rust infections.

A good case in point is the discovery of barley leaf rust in the South Stirling area this week where trace levels have just started to become apparent on volunteer barley at the late booting stage.

“It is good to see grain growers taking steps to minimise risk from self-sown cereals with green non-cropping paddocks in the eastern wheat belt being grazed and in some cases sprayed to reduce rust build-up opportunities.

Growers are advised to review their green paddocks for rust risk and where possible direct grazing pressure or spraying programs to continue to put pressure on rust survival and delay the emergence of rust threats for the 2005 cropping season.