PMEP Home Page --> Pesticide Active Ingredient Information --> Herbicides, Growth Regulators and Desiccant --> fatty alcohol to monuron (Telvar) --> monocarbamide (Enquik, WilThin) --> monocarbamide (Enquik, WilThin) NYSDEC Registration Approval 2/97

monocarbamide (Enquik, WilThin) NYSDEC Registration Approval 2/97

New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials
50 Wolf Road, Albany, New York 12233-7250                       John P. Cahill
Phone 518-457-6934      FAX 518-457-0629                   Acting Commissioner

                                               February 14, 1997


Mr. Gary C. Graham
General Manager, Registration and Technology
Entek Corporation
P.O. Box 458
Brea, CA 92822-0458

Dear Mr. Graham:

     Re: Registration of the New Active Ingredient, Monocarbamide Dihydrogen
         Sulfate, Contained in the New Pesticide Product WilThin 
         (EPA Reg. No. 68891-4)

     Entek Corporation applied for New York State registration on June 5, 1996 
for WilThin (EPA Reg. No. 68891-4) which contains the new active ingredient 
monocarbamide dihydrogen sulfate (also known as urea, sulfate).

     WilThin is a blossom thinner for use on apples, peaches and nectarines. 
The application rate is 14.99 lbs. active ingredient/acre. Only one 
application can be made during the bloom period of March 1 to May 20.

     The New York State Department of Environmental Conservation (the 
Department) has completed the review of the information supplied to date in 
support of the pesticide product registration for WilThin.

     WilThin is extremely caustic and corrosive. Studies conducted with 
mallards at higher than current label use rates resulted in eye, foot, and leg 
damage due to the corrosive action of sulfuric acid contained in this product. 
Because of these study results, application of WilThin is restricted to use of 
the diluted chemical and to ground application only. These mitigating factors, 
along with lower use rates than those used in the mallard studies, should 
adequately protect terrestrial wildlife from the use of WilThin in orchards.

     The United States Environmental Protection Agency (USEPA) required 
limited toxicological data for the federal registration of WilThin and, 
therefore, only a battery of acute toxicity studies was conducted. Summaries 
of these studies indicate that the product causes severe irritation upon 
contact with eyes or skin and is moderately toxic following acute ingestion 
exposure. Accordingly, the WilThin label requires that applicators and other 
handlers wear several items of personal protective equipment as well as 
requiring a 24-hour worker Restricted Entry Interval to reduce direct 

     Ingestion exposure from treated crops is highly unlikely as 
WilThin is applied before fruit development and the active ingredient 
rapidly breaks down to urea and sulfuric acid or sulfate salts. The 
USEPA granted a tolerance exemption for the active ingredient in 
treated crops.

     The Environmental Assessment Branch of the USEPA has waived the 
environmental fate data requirements for monocarbarmide dihydrogen sulfate 
because the environmental fate of urea and sulfuric acid is well known. When 
used according to label directions, WilThin is not expected to impact 

     Therefore, the Department hereby accepts for general use registration 
WilThin (EPA Reg. No. 68891-4).

     Enclosed are your New York State stamped "ACCEPTED" label and a copy of 
the Certificate of Registration.

     Please contact Maureen P. Serafini, Supervisor of our Pesticide Product 
Registration Section, at (518) 457-7446, if you have any questions.


                               Norman H. Nosenchuck, P.E.
                               Division of Solid & Hazardous Materials


cc: w/enc. - N. Kim/A. Grey - NYS Dept. of Health
             N. Rudgers/R. Mungari - NYS Dept. of Ag. & Markets
             D. Rutz/W. Smith - Cornell University