It is well known that weeds slow harvesting operations and increase combine repair costs; product may have excessive grain moisture and/or weed seeds in wheat3. Some have reported color changes and the taste of weeds in the product.
One commonly used product has been Roundup, and the label recommendations are the following: “This product provides weed control when applied prior to harvest of feed barley and wheat. For feed barley, apply after the hard-dough stage and when the grain contains 20 percent moisture or less. For wheat, apply after the hard-dough stage of grain at 30 percent or less grain moisture” 3.
There are concerns of the presence of glyphosate in shipments from US and Canada which they attribute to “the practice of pre-harvest spraying”. Therefore, some growers are looking for alternatives to this herbicide2.
Sharpen (saflufenacil) is a quick acting burndown product for broadleaf weed control in field crops and it has been labeled and approved in the US for this purpose.
Consulting with a BASF representative we learned that Sharpen is labeled in Arizona (not CA) for this use. The recommended rate is 1-2 fl oz., adding Ammonium Sulfate adjuvant and Methylated Seed Oil. Also, apply at the hard dough stage with no more than 30% moisture, with 10 GPA by ground or 5 GPA by air.
Knezevic (2009) stated “MSO was the adjuvant that provided the greatest enhancement of saflufenacil across all species tested. COC was the second-best adjuvant and provided control similar to MSO on many weed species. NIS provided the least enhancement of saflufenacil4.
An Agronomy Update from Kansas State University recommended to “Consult grain buyer to see if they will accept Sharpen treated wheat because of export restrictions”5.
References:
1. http://canola.okstate.edu/cropproduction/herbicides/labels/Roundup%20PowerMax%20Label.pdf
2. https://sustainablepulse.com/2019/08/29/unique-hair-testing-project-reveals-high-levels-of-glyphosate-and-ampa-in-members-of-the-japanese-parliament/
3. https://www.farmprogress.com/weeds/controlling-broadleaf-weeds-in-winter-wheat-is-essential
4. Knezevic, S. Z., Datta, A., Scott, J., & Charvat, L. D. (2009). Adjuvants influenced saflufenacil efficacy on fall-emerging weeds. Weed Technology, 23(3), 340-345.
5. https://cropwatch.unl.edu/2019/ksu-pre-harvest-weed-control-wheat-sharpen-update