Australian Herbicide Resistance Initiative (AHRI)

Crop seed contamination survey

Crop Contamination

Surveys were conducted on WA farms in 1999 and 2008 to address the issue of resistance mobility by seed movement by assessing grain samples (wheat, barley, lupins, canola) which were taken from crop planting seed stocks. Please use the following links to view the corresponding crop seed contamination survey information:

Map

2008

Most Australian farmers grow and conserve their own crop seed (especially cereals), however this seed can be contaminated with weed seed. Some seed cleaning operations are only partially effective and therefore weed seed is seeded into paddocks with the crop seed. For weeds such as ryegrass, wild oats, and wild radish, this weed seed can be herbicide resistant and it is therefore possible for farmers to unwittingly introduce herbicide resistance to crop fields.

Surveys were conducted on WA farms in 1999 (Powles & Cawthray) and 2008 (Michael et al) to address the issue of resistance mobility by seed movement by assessing grain samples (wheat, barley, lupins, canola) which were taken from crop planting seed stocks. This crop seed was then sieved to identify and quantify the level of contaminating weed seed and this weed seed was evaluated for herbicide resistance status. Information was collected on whether the crop seed had been seed-cleaned and perceptions as to contaminating weed seed.

The 2008 survey revealed that:

  • Nearly all of the surveyed WA farmers used or employed crop seed cleaning techniques
  • Significant weed seed remained in crop seed samples, especially ryegrass and wild radish.
  • Many WA farmers are unknowingly introducing weed seed and herbicide resistance into their paddocks
  • Cleaned crop seed had significantly lower levels of contamination thanuncleaned crop seed
  • 25% of crop samples were weed free, indicating that it is possible to achieve clean crop seed

Related Publications

Michael, P.J., Owen, M.J. and Powles S.B. (2010) Herbicide-Resistant Weed Seeds Contaminate Grain Sown in the Western Australian Grain Belt. Weed Science, 58, 466-472.

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