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Spring Frost Biggest Risk to Yields in WA Wheatbelt

12 September 2011

AUSTRALIA - Most of the Australian wheatbelt received adequate rainfall in August. Some waterlogging is present in far western shires and above average temperatures during August have accelerated crop growth over much of the region, reports the Western Australia Department of Agriculture and Food.

  • The Geraldton port zone is set up for well above average yields. Areas east of Merredin and around Salmon Gums are the main locations least likely to achieve average yields.
  • Spring frost at flowering is now the biggest risk to achieving average to better than average yields for many farmers in the southern and central wheatbelt.
  • The outlooks for above median rainfall in September for most areas could see well above average yields if this eventuates.

2011 Seasonal Outlook

Atmospheric and oceanic conditions across the Pacific Ocean continue at neutral levels, which are expected to remain through spring 2011. There is a chance that La Nina conditions may develop again over summer. Chances of an El Nino event are low.

The Department of Agriculture and Food's Statistical Seasonal Forecast (SSF) indicates above median rainfall is more likely over the South West and much of the central cropping region for August to October, based on June's patterns of sea surface temperature and atmospheric pressure. The Bureau of Meteorology's seasonal outlook for September to November is also expecting wetter than normal conditions for the southern part of WA.

Further detailed information and updates on the climate, weather and crops and the growing season outlook can be found on the department's website at

Weather Patterns: Typical winter-type weather patterns prevailed with regular cold fronts. Most activity was concentrated to the west of WA. Persistent north-westerly winds meant the Esperance region received less rainfall than average.

Rainfall: August rainfall totals were near average for the South West and much of the agricultural area. The eastern South Coast and Esperance region were below average. Seasonal rainfall since May has been below average for the South West and Swan Coastal Plain. The Perth area is also some 100 mm behind the year to date average. Most of the agricultural area has had near-average seasonal rainfall, with the northern region maintaining a wetter than normal pattern.

Temperatures: Monthly mean temperatures over southern WA have been higher than average for the month, most likely caused by persistent winds from the north-west and warm sea surface temperatures to the west of Perth. Despite this, there were several frost events through agricultural areas.

Pests and Diseases: Continued wet conditions in many parts of the grainbelt have resulted in increased cereal and canola diseases during August. Septoria and yellow spot on wheat have increased, with flag smut being found in northern and central wheatbelt areas. Foliar diseases on barley have increased in the Great Southern and South Coast. Cutworm caterpillars have been problematic this year throughout the state's grainbelt. Stem and stripe rust on wheat have been confirmed at Kellerberrin.

Further information can be found at and

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