Trouble controlling weeds? Submit seeds for herbicide resistance screening.
Submit seeds to MSU Plant & Pest Diagnostics to determine if herbicide resistance is impacting your farm.
As the harvest season is coming to a close, reflect on those weeds that escaped control. If you suspect there may be an herbicide resistance issue, consider collecting and submitting seed to Michigan State University Plant & Pest Diagnostics for screening.
To screen for resistance during the winter months, seeds are cleaned from dried plant material (Photo 1), treated for dormancy, grown in the greenhouse and treated with up to seven different herbicides (herbicides screened are based on the species, cropping system, suspected resistance and quantity of seedlings). The duration of the process depends on the species, but results are usually available no later than March. New incidence of resistance (i.e., not previously confirmed in Michigan) require additional testing.
If you plan to submit a sample, refer to the factsheet “Tips for Collecting Weed Seeds” to ensure you are collecting mature seed, have sufficient quantity and it is packaged properly. The factsheet also contains the submission address: MSU Plant & Pest Diagnostics, 578 Wilson Rd. Room 107, East Lansing, MI 48824. A submission form is needed with the sample, which can be found at the link or on the general Plant & Pest Diagnostics website.
The Michigan Soybean Promotion Committee will be sponsoring the testing of select species for Michigan soybean growers. The species included are: Palmer amaranth, waterhemp, horseweed/marestail, common lambsquarters, and common and giant ragweed. The cost of screening for non-soybean growers is $90 per sample. We also can offer screenings for other species not listed, but it is recommended you consult with us ahead of time (email firstname.lastname@example.org).
We ask that all samples be submitted no later than Nov. 22, 2019, to ensure testing over the winter months.
Further information on herbicide-resistant weed species in Michigan can be found on the “Cumulative map of herbicide resistant weeds in Michigan” (Photo 2).
MSU Plant & Pest Diagnostics is a fee-for-service laboratory that assists in determining the cause of a wide variety of plant health and insect pest problems.
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