The Minnesota Department of Agriculture is seeking input on two revised best management practices documents that involve agricultural herbicides and acetochlor.

The BMPs were drafted in 2004, revised in 2010 and recently were revised again. The proposed revisions were made in collaboration with the University of Minnesota Extension and other interested parties.

BMPs are implemented to protect groundwater and surface water from potential herbicide contamination resulting from normal agricultural use. Specifically, MDA says BMPs should be adopted when frequently detected herbicides have been found in Minnesota groundwater — acetochlor, alachlor, atrazine, metolachlor and metribuzin — or when acetochlor and atrazine have been found in state surface water at concentration levels of concern.

Acetochlor is an active ingredient in such products as Breakfree, Cadence, Confidence, Harness, Keystone, Staunch, SureStart, Surpass, Tripleflex, Overtime, Volley and Warrant.

If BMPs prove to be ineffective, MDA officials say that mandatory restrictions on herbicide use and practices may be required.

The MDA requests comments on BMPs in the following two documents, whose websites follow:

1. Agricultural herbicides (MDA's BMPs for all agricultural herbicides). MDA encourages the development of integrated weed management plans for every Minnesota farm.

BMP core practices include:

• scouting fields for weeds and matching management to the weed problem

• applying split or sequential herbicide applications

• evaluating surface drainage patterns in fields, and installing filter strips and establishing buffer zones for streams, sinkholes and tile inlets to protect surface water

• determining depth to groundwater in fields and consider protective practices in vulnerable areas

• rotating herbicide chemistries

• using proper application methods

• developing an irrigation management plan for groundwater protection

2. Acetochlor (MDA's BMPs for acetochlor).  Acetochlor BMPs are companions to the above BMPs for use with all ag herbicides:

• Maintain an application setback from surface water, tile inlets, wells and sinkholes.

• Soil-incorporate acetochlor.

• Maintain vegetative filters strips between areas where acetochlor is applied and points where field runoff enters surface water, tile inlets and sinkholes.

• Reduce acetochlor use by using other weed-control methods.

• Adopt conservation tillage practices appropriate for your farm’s topography and in southeast Minnesota karst areas.

• Adopt spray drift management and precision application methods.

Comments must be submitted by 4:30 p.m. Oct. 4.

Please submit comments and questions by email to Chahal Gurinderbir at [email protected].

Questions? Refer to MDA’s webpage on herbicide BMPs to protect water quality for more information.

Or, call Gurinderbir at MDA’s Pesticide and Fertilizer Management division, 651-201-6237