Comments Submitted on Prometryn

NCC's comments submitted to EPA on the agency’s preliminary ecological risk for prometryn noted that it meets critical weed resistance management objectives, especially because pigweed’s resistance to glyphosate has emerged.

Published: November 17, 2017
Updated: November 17, 2017

November 13, 2017

Office of Pesticide Programs
Regulatory Public Docket (7502P)
U.S. Environmental Protection Agency
1200 Pennsylvania Ave., NW Washington, DC 20460

RE: Docket ID Number EPA-HQ-OPP-2013-0032

Dear Christina Scheltema:

The National Cotton Council (NCC) appreciates the opportunity to comment on the Environmental Protection Agency’s (EPA) current registration review of Prometryn.  The NCC urges EPA to recognize the long-term registration of this crop protection product and to recognize the unique mode of action (MOA) it offers for resistance management scenarios.  As EPA urges producer to recognize the values of rotating chemical MOA’s for resistance management purposes, EPA must recognize rotation is not possible unless there are multiple MOA’s.  This product serves critical weed resistance management objectives especially since pigweeds resistance to glyphosate emerged.

The NCC is the central organization of the United States cotton industry.  Its members include producers, ginners, cottonseed processors and merchandizers, merchants, cooperatives, warehousers and textile manufacturers.  A majority of the industry is concentrated in 17 cotton-producing states stretching from California to Virginia. U.S. cotton producers cultivate between 9 and 12 million acres of cotton with production averaging 12 to 18 million 480-lb bales annually. The downstream manufacturers of cotton apparel and home furnishings are located in virtually every state. Farms and businesses directly involved in the production, distribution and processing of cotton employ more than 125,000 workers and produce direct business revenue of more than $21 billion.  Annual cotton production is valued at more than $5.5 billion at the farm gate, the point at which the producer markets the crop.  Accounting for the ripple effect of cotton through the broader economy, direct and indirect employment surpasses 280,000 workers with economic activity of almost $100 billion. In addition to the cotton fiber, cottonseed products are used for livestock feed and cottonseed oil is used as an ingredient in food products as well as being a premium cooking oil.

The NCC reached out to Extension Specialists in Texas and Georgia, and believe their following comments emphasize the importance of prometryn for cotton.

Texas has consistently planted over 50% of the cotton acreage in the entire U.S. for the past 7 years to a total of 6.9 million acres in 2017.  With limited moisture, weed management is one of Texas’ biggest pest management challenges. Currently in the state, herbicide resistance has been documented in perennial ryegrass (ALS inhibitors), barnyardgrass (PSII inhibitor), Palmer amaranth (PS II inhibitors and EPSP synthase inhibitors), kochia (ALS inhibitors), johnsongrass (ALS inhibitors), and tall or common waterhemp (EPSP synthase inhibitors).  Glyphosate resistant palmer and common waterhemp are the most problematic in Texas cotton due to reliance on glyphosate alone for weed management.  The development of resistance is only accelerated when any one chemistry or site of action is relied upon too heavily.  As noted in other states, resistance to additional modes of action such as the PPO’s, puts greater selection pressure on the few remaining effective chemistries and puts the sustainability of new technologies like dicamba at significant risk.  In cotton, prometryn continues to be an effective tool both PRE and POST applied for the control of select grasses and several small seeded broadleaf weeds, including palmer and common waterhemp. In some coarse soil types, prometryn provides greater crop safety than alternative chemistry and reduces the selection pressure on the foliar applied herbicides. It is therefore necessary that prometryn be retained as a tool for sustainable cotton production and as an effective site of action for the continued management of herbicide resistance.

Scott A. Nolte, Ph.D.
State Extension Weed Specialist
Texas A&M AgriLife Extension
Dept. Soil & Crop Sciences
2474 TAMU, 370 Olsen Blvd.
College Station, TX 77843-2474

Glyphosate-resistant Palmer amaranth has cost the Georgia cotton industry in excess of $1 billion.  Management plans are complex and costly.  Although these programs are diversified including herbicides in conjunction with tillage, cover crops and/or hand weeding, herbicides remain the backbone of an effective system.  Current overuse of PPO herbicides and glufosinate along with future overuse of dicamba poses a serious threat to cotton production sustainability.  University of Georgia recommended weed management programs include at least 5 classes of herbicide chemistry including prometryn as it offers a unique mode of action (photosystem II).

In Georiga, prometryn and other products with the same mode of action, offer growers a critical advantage.  With a corn, cotton, peanut, and soybean rotation, this type of chemistry is only used at planting or at layby in cotton.  The ability to use this tool, which can be effective on Palmer amaranth, not only protects our cotton crop but also protects each crop growing in rotation.  It is essential that academics and regulators work together to enhance the use of tools such as prometryn to protect cropping structures and long term sustainability.

Stanley Culpepper
Professor – Extension Weed Science
Tifton, CAES Campus
2360 Rainwater Road
Tifton, GA31793-5766

The NCC thanks the EPA for the opportunity to provide comment, and encourages EPA to make no changes to the current label of this safe product.


Steve Hensley
Senior Scientist, Regulatory and Environmental Issues
National Cotton Council