Cooperative Extension Offers Producers Diagnostic Service to Test Weeds for Herbicide ResistanceWed, 23 Aug 2017 15:39:32 CDT
Oklahoma State University’s Department of Plant and Soil Sciences is promoting diagnostic services for farmers, provided by the Oklahoma Cooperative Extension Service, the Oklahoma Wheat Commission and the National Institute of Food and Agriculture, U.S. Department of Agriculture, to test for herbicide-resistant weeds in Oklahoma.
According to a fact sheet distributed by the University, herbicide resistance is an increasing concern in Oklahoma crop production. Resistant weeds naturally exist in the Oklahoma landscape. However, we select for resistant populations with the continual use of a single herbicide or single mode of action. Given enough time and herbicide applications, resistant weeds will develop and can quickly take over a field. This is especially true in no-till or mono-crop systems, where herbicides or the same herbicides are the primary tool used for weed management. Herbicide-resistant weed populations limit effective herbicide options, complicate weed management decisions, and often increase weed management costs.
Producers in Oklahoma are encouraged to submit samples of the weeds in their fields for testing, to identify challenges that may be slowing developing on your property. The only way to know for sure if resistance is developing in your field is to test the suspected weeds. Early detection of herbicide-resistant weeds is an important step in designing an effective weed management program to prevent the development and spread of the resistant weed. Screening of potentially resistant weeds is a FREE service to any producer in Oklahoma, thanks to the organizations listed earlier.
Of all the weeds out there, the biggest and most immediate threats to farmers in the state that most likely to develop resistance include any pigweed species, Italian ryegrass, cheat, marestail/horseweed, kochia, giant ragweed and Johnsongrass.
If you decided to take advantage of this service, follow these steps in order to successfully submit a sample for herbicide resistance testing:
- Collect seed from fields sprayed during the current cropping season. Avoid collecting seed from field edges or areas not treated. Contact your local OCES County agricultural educator for assistance in seed collection.
- If possible, collect seeds from at least five mature plants. Maturity can usually be determined by how easily the seed will shatter from the seedhead. It also is important to collect enough seed for greenhouse testing-enough to fill half of a small coffee cup will provide plenty of seed for testing. Place seeds in a paper bag or large envelope for mailing.
- Each weed species should be submitted as a separate sample. Likewise, samples from multiple fields should be submitted separately.
- Complete the information form, found here, and submit it with your seed sample, to your local county Extension office.
After your sample is received, the seed will be grown in greenhouse facilities. Depending on the weed species, the crop from which the sample was collected and herbicide use history, the sample will be screened with one or several herbicides. Approximately three weeks after treatment, treated plant samples will be compared to nontreated and known-susceptible check samples to determine if resistance is present. Once the sample has been evaluated, the results will be summarized and returned to you, or the producer, who submitted the sample.
Source - Oklahoma State University
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