Information Requests Monitoring System

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Request ID: 116
Request From: Steve Toth
Date Requested: Apr 14, 2005
Request: Please note the following request for feedback regarding buffers for chlorsulfuron. USDA needs the any response by April 21 in order to respond to EPA. Please send any responses from your state/territory to the Southern Region Information Request Monitoring System by April 21, 2005. Thanks. Steve Toth ---------------------------------------- The registrant, DuPont and EPA are nearing final risk mitigation decisions for chlorsulfuron. EPA has asked for USDA feedback on the feasibility of mandatory 50 foot buffer for ground applications and a 350 foot buffer around the field for aerial applications of chlorsulfuron on crops (wheat, small grains, pasture/hay). Please note EPA is not addressing forest uses, rangeland uses and right-of-way uses in this decision at this time. Also, I do not have other details on the proposed final risk mitigation decisions to provide you at this time. EPA has delayed the chlorsulfuron RED from a March decision but wants to finalize in the next several weeks. By April 21, please provide me your feedback if the proposed 50 foot ground and 350 foot aerial buffers are not feasible and why. There will be a closure call (date unknown) organized by EPA to discuss all the final risk mitigation decisions. Grower groups will have a final chance to comment at that time. I will keep you apprised. Thanks in advance and thank you for your earlier feedback. See the attached file for more information on chlorsulfuron. Please do not hesitate to contact me if you have any questions or comments. Teung F. Chin, Ph.D. Biological Scientist Office of Pest Management Policy Agricultural Research Service United States Department of Agriculture LOCATED AT: USDA Animal & Plant Health Inspection Service 4700 River Road, Unit 149 (Room 5A66) Riverdale, MD 20737-1237 Phone (301) 734-8943 Fax (301) 734-5992

Responder: James Martin
State: KY
Date Requested: Apr 15, 2005
Not Important/Relevant to my state(s)
Response: The use of chlorsulfuron is not an isue in KY crops.

Responder: Charles Luper
State: OK
Date Requested: Apr 21, 2005
Response: Oklahoma has a big problem with the 50 ft and especially 350 ft setback zones for chlorsulfuron on wheat. This herbicide is widely used and one of the best herbicide choices for weeds in Oklahoma wheat. Oklahoma does not have problems with non target exposure with chlorsulfuron compared to other herbicides. Aerial application is needed to apply this herbicide in a timely matter in wet fields. By implementing these limites the aerial buffer would take away almost 40% of a producers acreage on a 1/2 section (320acre) wheat field that could be applied with chlorsulfuron. These setbacks are not supported by Oklaohma State Weed Scientists and the Oklahoma Wheat commission. Please see the comments from our small grains weed scientist below. Hi Charles, I would like to offer the following comments regarding a 50 foot buffer for use of Glean. You know that I have spent much of my career researching alternatives to herbicides for weed management in wheat. Yet, I am adamately opposed to imposing a 50 foot border or buffer around the edge of a wheat field for application of Glean. Here are my reasons: 1. Glean has been used for over 20 years and we have not had any problem with damage to nontarget species that I am aware of. We have had no credible complaints about such damage brought to our attention. 2. Glean is a herbicide that our farmers use primarily in wheat. The worst weeds in wheat are frequently found around the edges of the field. Controlling the weeds that are trying to invade a field, starting at the edges or borders of the field, is critical to preventing weeds from invading the entire field. I often recommend to farmers that they only need to spray the edges of their fields rather than the entire field. I have seen numerous fields where this practice is sucessfully followed. If for some reason, we could not spray these borders, we would soon find ourselves having to spray the entire remainder of the field. The reason for this is because grain harvesting equipment and tillage equipment would pick up the weeds from the edge of the field and transport the weed propagules all over the remainder of the field. This is simply totally unacceptable to an effective integrated weed management program. As farmers have gained control of the weeds in their fields over the past decade or more, some have adopted the practice of "patrolling the borders" with a herbicide. This has resulted in reduced herbicide use and it saves them money also. I expect this practice to continue to increase, resulting in decreased herbicide use. 3. For farmers who still have widespread weed problems, Glean if often applied with liquid fertilizer carrier. That provides added insurance against drift because the liquid fertilizer has less tendency to drift than water, because it is heavier and is applied as a more course spray. If they could not apply Glean to the outside 50 feet of a field, they could not simultaneously fertilize the outside 50 feet of the field. That would likely result in the farmer having to go over his entire field an extra time, and spend more money, and burn more petroleum fuel to do that. Adding such inefficiencies to the system simply does far more harm than good, and would increase the potential for drift. 4. Wheat growers seldom have a field bordered by water. In contrast, fields are often bordered by weeds that, if left uncontrolled, may cause traffic safety problems by blocking the view of drivers on rural roads, especially at intersections. Allowing another 50 feet wide strip of weeds along every rural road would simply exacerbate this problem and lead to more traffic fatalities on rural roads. 5. If EPA imposes a 50 border for application of Glean, it would probably lead farmers to simply switch to other herbicides that do not have such a border restriction. This would increase the use of herbicides that are more toxic and have far greater potential for drift and damage to nontarget species, including bromoxynil and 2,4-D. I simply can not imagine why we would want to do that. Charles, I have read sketchy information about EPA wanting to impose a 50 foot border for application of Glean. I have pondered that and I have simply concluded that such a move would be unwise, considering the negative effect on weed management programs for wheat. It would likely have the opposite of the desired effect, i.e., it would compound weed management problems, increase pesticide use, increase pesticide drift, and force farmers to use herbicides that are less effective and that have more potential for environmental damage. Thank you for asking me to comment on this proposal. Please forward my comments to the appropriate individuals. I have added my telephone number below, if they would like to contact me directly to discuss this issue at greater length. Sincerely, Thomas F. Peeper Professor of Weed Science Oklahoma State University telephone: 405-744-9589
Attachment included in response [Download]

Responder: Henry Fadamiro
State: AL
Date Requested: Apr 21, 2005
Not Important/Relevant to my state(s)
Response: The active ingredient, chlorsulfuron, is not labeled for use in crops (wheat. small grains, pasture/hay) in Alabama. Telar (chlorsulfuron) has some noncrop and right-of-way use in Alabama, but this area was not covered by the information request.

Responder: Bob Scott
State: AR
Date Requested: Apr 22, 2005
Response: These buffers are just a bad idea for any product. It has been my experience that the end result is that often more lbs of active are used in the "buffer zone" to make up for not using the product that needs to be used, creating more "risk" to everything. Also, I often have to recommend less effect combinations of multiple products. If the buffer zone refers to a buffer between the crop and an endangered species, I guess that is OK, but I question how you are to know if there is an endangered species around? Bob Scott Arkansas Extension Service

Responder: Alan York
State: NC
Date Requested: Apr 22, 2005
Response: This is the first I have heard about this, and I have no idea what the concerns are. We do not use straight chlorsulfuron in North Carolina small grains. We do, however, use a product called Finesse, which contains chlorsulfuron plus another sulfonylurea. Since I don't know what the concerns are, it is more difficult for me to respond. However, the buffers seem prohibitive to me. Most of the Finesse in North Carolina is used in the Piedmont, where field size is typically pretty small. A 50-buffer around the field, in some cases, would be a substantial portion of the field left untreated. A 350-ft buffer is ridiculous. Assume a square field with 10 acres of land. The dimensions would be 660 by 660 ft. With a 350-ft border on all sides, one could not treat the field at all. Remember that 10-acre fields are the norm in our Piedmont. If one had a 20-acre square field (933 ft square), and if 350 ft are left off all sides, one could treat only 1.25 acres in the 20-acre field. A buffer like this may not be a concern in Kansas, but in Piedmont North Carolina, it is prohibitive. Alan York Department of Crop Science North Carolina State University

Responder: Mark Mossler
State: FL
Date Requested: Apr 29, 2005
Not Important/Relevant to my state(s)
Response: In talking to our weed scientists, the proposed modifications to the chlorsulfuron label would not greatly affect Florida producers.

Responder: Mark Mossler
State: PR
Date Requested: Apr 29, 2005
Not Important/Relevant to my state(s)
Response: Chlorsulfuron is not currently labeled in Puerto Rico.

Responder: Robert (Bob) Bellinger
State: SC
Date Requested: May 10, 2005
Response: Steve, An FYI. I never received any return comments on this request. Bob B.

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