Resistance Testing

Seed Assays for Herbicide Resistant Weeds

Herbicide-resistant weeds are an ever-increasing problem in Western Canada. Ag-Quest conducts resistance tests to help producers identify herbicide-resistant populations in weed seed samples.

Growth room assays are conducted on live plants treated with the requested herbicide(s). Test results are derived by comparing the growth and development of tested weed samples with known resistant and susceptible weed populations.

We can test major annual weeds (wild oats, green foxtail, cleavers, kochia, lamb’s-quarters, redroot pigweed, shepherd’s-purse, smartweed, stinkweed and wild mustard, etc.) with most post-emergent herbicides and some soil-applied herbicides.

We will not disclose the grower/field information without consent.

Notes

• Actual response under field conditions might vary from lab results: Assay results are based on the sample of weed seeds sent to our lab. Results will only reflect the herbicide resistance in that particular sample, which may or may not be representative of the entire field (depending on sample collecting methods). Due to environmental and other factors, actual response under field conditions may occasionally vary from the lab results.
• New tests: New tests are being developed in response to customer demand. If you would like us to test for a herbicide that is not on the list, please contact us at 204-776-2087, and we will look into developing more tests.
• Liability and warranty: Any liability for work contracted to Ag-Quest will be limited to the quoted cost for the work affected. Except for the quoted cost, any other warranty or liability of any kind and recovery of any incidental or consequential damages or claims is specifically excluded.

Seed Sample Requirements

In order to facilitate accurate, reliable test results, please follow the sample requirements below:

1. Collect mature and dry seeds.
   • Immature seed can reduce germination and seedling vigor, resulting in inaccurate results or inability to conduct test at all.
   • Be aware of late-maturing weed species such as kochia, which may not be ready to sample at the time of crop desiccation or harvest.
   • Damp seed may produce mold and make the sample unusable. After sample collection, spread out seeds on a paper to air dry for a few days at room temperature before packing.
   • Field should not be sprayed with pre-harvest glyphosate, which may reduce germination.
2. Put dry seeds in paper bags or envelopes; do not use plastic bags.
   • Plastic bags trap moisture and increase the chance of spoilage.
   • We recommend paper lunch bags (approx. 5 x 3 x 10 inch) filled ½ to ¾ with pure seed. This amount should be enough for multiple tests.
3. Sample should consist of pure seed and be clean (separated from chaff).
   • Many weed seeds enter a period of dormancy in the fall. In order to overcome this dormancy in wild oats, we individually remove the seed coat and puncture the seed.
   • This is a time-intensive process, especially with excessive chaff. As a result, samples of poor quality may incur an additional processing fee of $10 per test.
4. Ship samples ASAP. Samples received before December 31 will help ensure timely results. Preferred shipping method is via Purolator.

The above guidelines represent ideal conditions. As field researchers, we understand that situations are not always ideal and will make a reasonable attempt to test less than ideal samples.

Minimum Requirements for Testing

At a minimum we require 25 g of pure weed seeds for each herbicide test.

• Weed seeds that have been sprayed with pre-harvest glyphosate may still be viable, depending on maturity at the time of application.
• Seeds collected before ideal mature stage may still be viable. Please ensure these samples are thoroughly dried and cleaned (pure seeds only, remove chaff) to avoid spoilage.

Deadline for Submission

Sample submission deadline: December 31

Payment and Invoicing

• Do not send payment with the samples.
• Results and invoice will be emailed to the individuals listed on the Seed Sample Submission Form.
• Please pay based on invoice.
• Make cheques payable to Ag-Quest Holding Ltd.
• Include PO# if needed.
• We are not able to bill third parties.
• Credit cards will be accepted and a processing fee of 4% will be assigned to the invoice.
• Call 204-776-2087 to process payment.
• Include your return address on the shipment to ensure it is received by Ag-Quest.