EOI Sow thistle glyphosate resistance survey

Expressions of interest in participating in a survey testing of sow thistle for glyphosate resistance

Glyphosate resistance survey of the weed common sowthistle across the northern cropping region

Populations of common sowthistle (Sonchus oleraceus) have recently been confirmed as resistant to glyphosate in northern New South Wales. The question remains as to how widespread this resistance is across the northern cropping region of Australia. To address this question, the Grains Research and Development Corporation (GRDC) are funding a comprehensive and coordinated survey of common sowthistle across the northern region to assess and map the occurrence of glyphosate resistance. The Queensland Department of Agriculture, Fisheries and Forestry (DAFF) will be undertaking the research, in conjunction with NSW DPI and grower solutions groups NGA, GOA and CQGS.

Common sowthistle is the most common weed in the northern cropping region of Australia and its effective control is vitally important for sustained and profitable agricultural production. Our heavy reliance on glyphosate to control the weed in fallows has resulted in glyphosate resistance.

To date few samples have been tested for resistance to glyphosate and these samples have been sourced primarily from populations in northern New South Wales. Our new survey aims to get a truly representative assessment of the extent of glyphosate resistance in common sowthistle across the entire northern region.

Results from the survey will provide a benchmark of existing sowthistle resistance and identify hot spots of resistance across the region. This information will assist industry to better target and sustainably control sowthistle in the long-term. A direct benefit for growers and agronomists is the characterisation of glyphosate susceptibility in their sampled populations and hence an understanding of whether glyphosate will be effective.

DAFF will be working with the grower solutions groups and their agronomist networks to collect sowthistle seed samples for testing. However, outside of these networks, any agronomist or farmer interested in participating is welcome to contact Annie about becoming involved (see contact details provided).

Each participating agronomist (or farmer) will be asked to collect and submit samples from common sowthistle populations for testing by DAFF. To provide a comprehensive geographic spread of sowthistle resistance, we need as many volunteer collectors as possible to submit samples. These seed samples can be collected from populations of common sowthistle occurring either within crop or in fallow. We are asking for 4 samples from each volunteer (with each sample to come from a different cropping property), but we understand that this may not be possible in each case and will gratefully accept smaller numbers of samples.

Kits containing all necessary materials and easy-to-follow instructions for the collection of seed samples will be posted to participants in September, so we will need our volunteer seed collectors to provide their mailing address (or that of a convenient collection point, e.g. the office of their grower solutions network). It is anticipated that screening of samples will start in October 2014, which will involve pot trials of each sampled population. Depending on the number of samples received, we will aim to provide results to participating agronomists within 3 to 4 months of receiving the sample.

Resistance testing results will only be provided back to the agronomist or grower who collected the sample. The results will be identified using a unique code for each sample. Pooled results across the whole northern region will be presented in reports and publications, but in such a manner that there will be no obvious relationship to any individual agronomist, farmer or property. Individual results will remain confidential.

Your assistance with this survey is crucial to ensuring comprehensive geographical coverage of the northern region. Surveys that gather information to assess the extent of herbicide resistance are a critical step in risk management, helping to preserve the effectiveness of this hugely important herbicide, glyphosate. We greatly value your involvement and sincerely appreciate your efforts on behalf of the project.

To register your interest in participating in this survey please Click Here