WYOMING WEED AND PEST COUNCIL

(WWPC)

GOVERNOR, Matt Mead PRESIDENT, John Watson

__________________________________________________________________________________________ 6607 Campstool Road - Cheyenne, WY 82002-0100 - (307) 777-6585 or 1195 South Guernsey Road – Wheatland, WY 82201

_______________________________________________________________________________________________________________________________________

Executive Directors

Slade Franklin

State Coordinator, Cheyenne

Jim Cotterman

Secretary, Wheatland

Walt Hartung

Area 1, Cody

Quade Schmelzle

Area 2, Gillette

Gail Mahnke

Area 3, Lusk

Adrian Hunolt

Area 4, Daniel

Randy Laughter

Area 5, Green River

Lindsay Wheat, Treasurer

Area 6, Laramie

January 27, 2014

Wyoming Department of Agriculture

Attn: Polly Cross – Tech. Services Asst. Manager

6607 Campstool Road

Cheyenne, WY 82002

Mrs. Cross,

On behalf the Wyoming Weed and Pest Council, I would like to request the Wyoming Department of 

Agriculture to seek an approval of a Section 18 label for the use of Dimilin to control grasshoppers in 

alfalfa. The twenty-three Weed and Pest Control Districts in the state work diligently in assisting private, 

state and federal land managers in controlling grasshoppers on their respective grounds. This Section 18 

label for Dimilin has historically been an important tool for them in succeeding with their control 

programs. 

In Wyoming, grasshoppers have been a significant issue over the last three years. In 2010 and 2011, the 

state experienced higher than average hatches in most parts of the state. Unmanaged, they would have 

had a significant impact on the ecological health of rangeland and croplands both, not to mention a 

significant economical impact on the agricultural community. Through the use of insecticides, mainly 

Dimilin, the Weed and Pest Control Districts were able to mitigate their impacts and save the agriculture 

community from losses estimated near $11 million dollars for 2010. A key to that success was the 

Section 18 label for the use of Dimilin on alfalfa. Alfalfa proved to be a major hatching area for the 

grasshoppers, and Dimilin was the only insecticide available that would allow the Districts to mitigate 

the issue BEFORE the grasshoppers could significantly damage the alfalfa field. 

Although we are not expecting grasshopper outbreaks even near the 2010 and 2011 levels, there are 

several areas where we expect higher than normal hatches to occur. Some of these areas will have 

alfalfa fields within them. The approval of this Section 18 label will help the Weed and Pest Control 

Districts to prepare and implement management programs that will mitigate the impacts from any 

outbreaks.

Sincerely,

John Watson

President
JOB/C544

Chemtura Corporation

199 Benson Road

Middlebury, CT 06749

203-573-2454 tel

February 14, 2014

Wyoming Dept. of Agriculture

Technical Services

2219 Carey Avenue

Cheyenne, Wyoming 82002-0100

Attention: Polly Cross, Assistant Manager

Subject: Letter of Support for Emergency Exemption, Section 18

For Dimilin® 2L on Alfalfa in Wyoming

Dear Ms. Cross,

Chemtura Corporation supports the State of Wyoming Section 18 application for

the use of Dimilin 2L, EPA Reg. No. 400-461, on alfalfa hay and mixed grass/alfalfa hay 

for control of grasshoppers and Mormon crickets. Chemtura agrees to supply 

commercially ready product via our normal channels of trade. 

We would appreciate it if you would send us a copy of all EPA correspondence 

on this subject to Caroline Maselli at the above address. Should you have any questions, 

please call Caroline at 203-573-2449 or e-mail caroline.maselli@chemtura.com. 

Sincerely,

Chemtura Corporation

Allen R. Blem

Product Registration Mgr., North America
DIMILIN® is a Registered Trademark of Chemtura Corporation, 199 Benson Road, Middlebury, CT 06749

All applicable directions, restrictions, and precautions on the registered product label for

Dimilin 2L (400-461) are to be followed.

These Use Directions must be in the possession of the user at the time of the pesticide application. 003

It is a violation of Federal law to use this product in a manner inconsistent with its labeling.

FOR CONTROL OF GRASSHOPPERS AND MORMON CRICKETS IN ALFALFA AND MIXED GRASS/ALFALFA HAY

SITES AND ACREAGE TO BE TREATED:

ALFALFA AND MIXED GRASS/ALFALFA HAY

GRASSHOPPERS AND MORMON CRICKETS: For optimum results, apply DIMILIN 2L when grasshoppers/Mormon crickets have reached the 2nd to 3rd

instar stage of development. DIMILIN will not effectively control grasshoppers and Mormon crickets once they reach the adult stage. 

Do not exceed 2 fl. oz. per cutting or 4 fl. oz per acre per year. 

Do not apply closer than 14 days prior to harvest.

Do not apply DIMILIN directly to or allow to drift to water or wetlands. When disposing of equipment wash water or rinsate, do not contaminate water.

Do not plant food or feed crops in DIMILIN treated soils within 1 month following last application, unless DIMILIN is authorized for use on these crops.

Do not enter or allow workers into treated area during the restricted entry interval (REI) of 12 hours.

Do not apply within 25 feet by ground or within 150 feet by air of bodies of water such as lakes, reservoirs, rivers, permanent streams, natural ponds, 

marshes or estuaries. All applications must include a 25 foot buffer vegetative strip within the buffer zone to decrease runoff.

SECTION 18 EMERGENCY EXEMPTION FOR ALFALFA AND MIXED GRASS/ALFALFA HAY

FOR USE ONLY WITHIN THE STATE OF WYOMING

RESTRICTED USE PESTICIDE

Due to toxicity to aquatic invertebrate animals.

For retail sale to and use only by Certified Applicators, or persons under their direct

supervision, and only for those uses covered by the Certified Applicator's certification.

Dimilin® 2L

INSECT GROWTH REGULATOR

SUSPENSION CONCENTRATE

Crops Pests

Application Rate

 (fl oz/acre) Application Timing

Alfalfa and Mixed 

Grass/Alfalfa Hay

Grasshopper 0.75 - 2 Use 1 application on early instar (majority in the 2nd through 4th instar nymphal stages). 

For best results use high rate on heavy infestations or dense foliage. 

Mormon 

cricket

May be used in a RAATs (Reduced Area and Agent Treatment) application on early instars. A RAATs application is an IPM strategy that takes advantage of grasshopper movement and conservation biological control to allow Dimilin 2L to be applied on a reduced 

treated area and at reduced rates, while sustaining acceptable control. 

The rate range to use per acre and amount of area treated will depend on grasshopper/ 

Mormon cricket age, plant canopy and topography. Skip up to 50% of the infested area 

(every other swath) and use the lower rate under uniform topography with early instar 

ages and sparse vegetation. If the majority of the population is late instars, vegetation 

is dense, terrain is considered rough, and conditions are hot during treatment, then the 

coverage and rate of DIMILIN 2L should be increased up to a blanket (100%) coverage 

with 1 fl oz per acre.

Applications may be made after each cutting of alfalfa. Do not apply more than three 

applications per year.

DIMILIN will not effectively control grasshoppers and Mormon crickets once they reach the adult stage

Aerial application: For low/high volume application, apply in 2 to 10 gallons of water per acre. For ULV application, apply in a minimum of 12 fl. ozs. 

total volume per acre.

Ground application: For low/high volume application, apply in 2 to 30 gallons of water per acre. For ULV application, apply in a minimum of 12 fl. ozs. 

total volume per acre.

Regardless of application type, total spray volume used must ensure thorough coverage of the target crop. Aerial and ULV spray mixtures should 

include an evaporation/drift retardant product at use rates prescribed on the specific product label, particularly when conditions are favorable for 

water evaporation (e.g., high air temperature and/or low humidity). When using oil type evaporation/drift retardant products, be sure to maintain a 

ratio of at least 2 parts water to 1 part oil.

For low volume and ULV applications, make sure that the spray mixture in the boom contains the correct concentration of Dimilin 2L before application begins, and be sure that good agitation is maintained throughout mixing and application.
Alexandre V. Latchininsky, Ph.D., Chair Clint Burfitt, Vice Chair Paul E. Blom, Sec./Treas.

University of Wyoming Utah Dept. of Agriculture Oregon Department of Agriculture

Department 3354 – Ecosystem Science and Management Box 146500 30588 Feedville Road

1000 E. University Avenue Salt Lake City, Utah 84114-6500 Hermiston OR 97838

Laramie, WY 82071-2000, USA Phone 801-538-7184 45.80570 -119.29911

Phone 307-766-2298 Fax -801-538-7189 Work 503-508-1253

Fax 307-766-6403 cburfitt@utah.gov Fax 206-666-3981

latchini@uwyo.edu pblom@oda.state.or.us, blom.paul.e@gmail.com

NATIONAL GRASSHOPPER MANAGEMENT BOARD

Judy Ball

Chemtura Corporation

199 Benson Road

Middlebury, CT 06749 USA

Tel 203-573-2449, Fax 203-573-3394

judy.ball@chemtura.com; www.chemtura.com

31 January 2014

Dear Dr. Ball

As Chemtura AgroSolutions is aware, grasshoppers and Mormon cricket outbreaks pose a significant threat to the 

agricultural and economic stability of many western states. To help combat these outbreaks personnel from USDAAPHIS-PPQ, State Departments of Agriculture and county officials conduct small to large-scale spray programs to assist 

farmers, ranchers and other land managers in protecting their agricultural resources as these outbreaks occur. Currently, 

the most widely accepted “Best Management Practices” in several states for these programs is applying Dimilin® 25W 

(active ingredient: Diflubenzuron) with a Reduced Agent and Area Treatments (RAATs) strategy. Dimilin® 25W has 

proven itself as the insecticide of choice based on its mode of action, efficacy and minimal impacts on non-target 

beneficial insects such as the honeybee.

Unfortunately, the current Dimilin® 25W label has its drawbacks. Although the typical state and federal grasshopper 

management program targets rangeland protection, large scale management blocks often have smaller areas of row crops

and other production agriculture included within the treatment boundaries. Under FIFRA, all pesticides must 

successfully complete an assessment process with the Environmental Protection Agency for potential residues that might 

enter in the food chain. Currently Dimilin® 25W is limited by label in its applicability to many crops. For most cases this 

is immaterial as most row crops do not provide the proper conditions for Dimilin® 25W use. However, alfalfa and mixed 

grass/alfalfa hay does provide suitable and susceptible habitat that can be protected through the use of Diflubenzuron at 

the proper grasshopper growth stage. This is why many western states have annually requested a Section 18 Emergency 

Exemption for Diflubenzuron use on alfalfa or mixed grass/alfalfa production. The Section 18 label has allowed program 

managers to create large contiguous spray blocks that are complimentary to the use of Dimilin® 25W and to a successful

grasshopper management program.

The National Grasshopper Management Board membership, consisting of grasshopper management professionals from 

Federal, State and County programs, is respectfully requesting an update to the current status of registration for alfalfa or 

alfalfa/mixed grass on the Dimilin® 25W Section 3 label. In the past five years, various members of the Board have been 

advised that the full registration of this use is forthcoming, yet many states are still required to issue Section 18 labels.. 

The Board is also concerned that in the future the EPA may not continue issuing the Section 18 label based on the broad 

interpretation of what “Emergency Conditions” are under the Section 18 process.

We look forward to an update that we may share with our membership.

Sincerely,

Alexandre V. Latchininsky, NGMB Chair