The Iowa Natural Resources Conservation Service (NRCS) has released a “technical note” that explains control options for Palmer amaranth in Conservation Reserve Program plantings, such as CRP pollinator plantings. There's also a new Iowa State University bulletin describing control options noted in the NRCS technical note.
“Agronomy Technical Note 40” includes the most detailed Iowa information to-date released by USDA on recommended/allowed eradication methods, CRP contract termination, monitoring fields for infestations, and controlling the spread of Palmer amaranth. Iowa NRCS drafted the technical note, with input from Iowa State University, private crop consultants and farm and conservation organizations, with review and approval by the USDA. The best control results recommended are hand pulling, flame weeding and spot herbicide treatment along with mowing, it says. Broadcast herbicide application using a pre-emergence or post-emergence broadleaf herbicide also an option. Broadcast applications of a non-selective herbicide is also an option on CRP contract acres certified to have 100 or more Palmer amaranth plants present. Tillage is not recommended.
In addition, be aware that as of today, there are no herbicides labeled to control Palmer amaranth on CRP fields. The Iowa Department of Agriculture and Land Stewardship and two registrants (BASF and Syngenta) have been working cooperatively to get EPA approval of an emergency “24(c) special local need” label for Dual II Magnum and Zidua. Both are selective rate-dependent residual preemergence herbicides for controlling Palmer amaranth. Farmers using these products will want to closely review the new special local need label directions, once available, for this specific use in CRP fields. These two products are not approved yet, but hopefully will be soon. These are the only products for which registrants have applied to EPA for emergency use, so far. They will only be allowed for distribution and use on CRP fields in Iowa; no other states, at this time.
Also, there's a new Iowa State University bulletin describing control options noted in the NRCS technical note that will soon be placed on the ISU Extension Store website. It will be updated to include information on the two preemergent products as soon as they are approved.
Farmers dealing with Palmer amaranth in CRP will want to follow these recommendations closely so as not to violate their CRP contract terms. If farmers have questions about the control recommendations or whether a planned action may violate the terms of their CRP contract, they should check with both their county NRCS and Farm Service Agency office first. NRCS is the technical service provider to FSA on the CRP program, but it is FSA that will make decisions on whether a farmer’s actions are in compliance with the terms of a CRP contract. Both agencies, as of today, are still discussing how to share responsibility for making technical recommendations and compliance determinations.
FSA makes decisions regarding contract termination and resulting repayment of CRP rental payments, cost-share and liquidated damages, if any, should a contract be terminated. It is anticipated that these kinds of payments will be forgiven, but the process may include the county and state FSA committees, and the national FSA office, depending on the type of payment and the amount. FSA also makes decisions on allowable cost-share for control measures (unofficially, some herbicide treatments can be reimbursed; more information about this is forthcoming).
This division of responsibilities between the two agencies may cause some confusion, therefore it is best to be certain before implementing a control measure so as to avoid potential problems.
In addition, Iowa's noxious weed law was amended in the recently-ended legislative session. House File 410 was signed by the governor April 21 and classifies Palmer amaranth as a primary noxious weed. While the weed law gives counties the authority to fine landowners who fail to control noxious weeds, and, if necessary, enter land to control the weed and assess the landowner costs associated with the control efforts, the listing of Palmer amaranth as a primary noxious weed is not intended to interfere with landowners' and farmers' CRP contract compliance, or limit USDA cost-share options for management or control. The law change makes an exception for a county's authority on private land enrolled in CRP by requiring the cooperation of the USDA.
FSA and NRCS plan to provide that training to county staff in the next week or so about this information. After the training, famers should contact their county USDA Service Center, their crop consultant or ISU Extension for more information.
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