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Tebuconazole - Registration of a Major Change in Labeling for Raxil Thiram Flowable Fungicide 9/96

New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials
50 Wolf Road, Albany, New York 12233-7250
Phone 518-457-6934 FAX 518457-0629

September 9, 1996

Mr. Dennis McFadden
Manager
Toxicology & Regulatory Affairs
Gustafson, Inc.
P.O. Box 660065
Dallas, TY 7525S-C065

Dear Mr. McFadden:

Re: Registration of a Major Change in Label for the Active Ingredient -
Tebuconazole Contained in the Pesticide Product Raxil Thiram Flowable
Fungicide (EPA. Reg. No. 7501-151)

The New York State Department of Environmental Conservation (NYSDEC) has
accepted your application for the registration of the major change in
label for the active ingredient, tebuconazole, contained in the
pesticide product Raxil Thiram Flowable Fungicide (EPA Reg. No. 7501-
151), for use as a seed treatment on barley, wheat, and oats in New York
State.

Gustafson, Inc., submitted an application on August 16, 1996, for
registration of the pesticide product Raxil-Thiram Flowable Fungicide
(EPA Reg. No. 7501-151) containing 0.6% tebuconazole and 20% thiram, as
a seed treatment for wheat, barley, and oats in New York State. Raxil-
Thiram Flowable Fungicide combines the systemic action of tebuconazole
with the surface action of thiram to control or suppress various seed,
seedling and soil-borne diseases of wheat, barley, and oats.

Thiram is currently registered for use in New York State by Gustafson,
Inc., as a seed treatment for barley, wheat, and oats. Tebuconazole was
under review for the Bayer Corporation Pesticide Product Elite 45 DF
Foliar Fungicide (EPA Reg. No. 3125-388) for use in orchards as a ground
spray for bananas, cherries, peaches, and nectarines. Bayer Corporation
gave permission for the Department to access their data on tebuconazole
for registration of Raxil-Thiram. The reviewers agreed to combine
Raxil-Thiram with the Elite review in the interest of efficiency.

Bayer Corporation Inc., submitted an application and supporting
documentation, on April 2, 1996, for the registration of the new active
ingredient, Tebuconazole, contained in the pesticide product Elite 45 DF
Foliar Fungicide (EPA Reg. No. 3125-388). The active ingredient
Tebuconazole (technical

name: alpha-[2-(4-chlorophenyl)-ethyl]-alpha(1,1-dimethylethyl)-lH-
1,2,4-triazole-1-ethanol)) is an effective fungicide for control of
brown rot (blossom blight, fruit rot) on peaches, cherries, and
nectarines, as well as powdery mildew and leaf spot on cherries. The
Department accepted for registration the new active ingredient,
tebuconazole, on September 5, 1996.

The data package for Raxil-Thiram was reviewed by the NYSDEC's Division
of Fish, Wildlife & Mineral Resources (DFW&MR); our Technical Support &
Laboratory Services Section (TS&ES); our Pesticide Product Registration
Section; and the New York State Department of Health (NYSDOH).

The DFW&MR Bureau of Environmental Protection (BEP) in a memorandum
dated August 20, 1996 did rot object to registration. Raxil-Thiram is
used as a seed treatment on wheat, barley, and oats. The amounts of
tebuconazole available to foraging wildlife are similar for both Elite
and Raxil Thiram. BEP has never conducted a technical review of thiram.
The limited amount of information submitted with the data package for
Raxil-Thiram indicated that the use of thiram in a seed treatment will
not adversely impact fish and wildlife. Other uses of thiram will need
to be supported with a complete data package due to the increase in
exposure to fish and wildlife.

The NYSDOH stated in their review that tebuconazole was not highly toxic
to laboratory animals in acute studies but the formulated product can
irritate the eyes and skin and is a sensitizer. Technical tebuconazole
caused a variety of effects in laboratory animals in chronic studies at
relatively low doses and also produced some developmental effects in
rodents and rabbits. The United States Environmental Protection Agency
(USEPA) Office of Pesticide Programs calculated an oral reference dose
of 0.03 milligrams per kilogram body weight per day for tebuconazole,
based on a no-observed-effect level from two chronic dog studies
combined and an uncertainty factor of 100. This value has not yet been
adopted on USEPA's Integrated Risk Information System. Tebuconazole
caused liver tumors in a chronic mouse study and is structurally similar
to other triazole pesticides that also cause liver tumors. The USEPA's
Carcinogenicity Peer Review Committee classified tebuconazole as a Group
C (possible human) carcinogen.

There are no chemical-specific federal or State drinking water/
groundwater standards for tebuconazole. Based on its chemical
structure, tebuconazole falls under the 50 milligram per liter general
New York State drinking water standard for an "unspecified organic
contaminant" (NYCRR Part 5 - Public Water Systems). Based on the oral
reference dose for tebuconazole (0.03 milligrams per kilogram body
weight per day) and the USEPA procedures for determining maximum
contaminant level goals for Group C carcinogens (Federal Register, 55:
30374-30375, July 25, 1990) a potential chemical-specific drinking water
standard of 21 micrograms per liter (ppb) can be calculated for
tebuconazole.

Based on their review, NYSDOH does not expect significant dietary
exposure to the general public from the labeled uses of Raxil-Thiram
Flowable Fungicide. Worker exposure should also be limited, as the
product label requires applicators and other handlers to wear personal
protective equipment. Therefore, NYSDOH does not object to the
registration of Raxil Thiram Flowable Fungicide for the labeled use as a
seed treatment on barley, wheat, and oats.

The TS&LS Section stated in their tebuconazole review that they did not
object to the labeled use of Elite 45 DF Fungicide on orchards.
However, if Bayer Corporation applies for a major change in label to use
tebuconazole at a higher application rate or for field crops or turf,
additional review will be needed.

The environmental fate data review indicated the following information:
There was no hydrolysis in sterile water; the aqueous photolysis half
life is 600 days; the soil photolysis half-life is 191 days; the aerobic
metabolism half-life in a field study is 610 days, and a calculated
half-life is 800 days; the anaerobic metabolism half-life is 400 days;
the koc in a clay soil is 906 to 1251; the aqueous solubility is 25 ppm;
and the aged leaching study indicated that tebuconazole is relatively
immobile. There were several degradates, all less than 3% of the
parent. The maximum application rate is 3 lbs. of product per acre per
crop per season. Tebuconazole is 45% active. The inerts are not
expected to be solvent carriers. For ease of modeling, TS&LS assumed
that a crop season is one calendar year for peaches, cherries, and
nectarines.

As an added precaution, groundwater simulation models (LEACHP) were run
on this compound for a Howard soil and a Riverhead soil. The parameters
indicated that tebuconazole is a persistent compound with little
degradation and low mobility in the vadose zone. For Howard soil with
application to barren soil, essentially none of the compound leached to
the water table. For Riverhead soil with application to barren soil,
concentration peaks at less than 3 ppb at the end of a ten-year period.

In their review of Raxil Thiram, TS&LS did not object to registration
based on the environmental fate data and the computer modeling used for
the Elite 45 DF review. Tebuconazole is immobile and persistent, and
when used according to label directions on barley, wheat and oats is not
expected to impact groundwater. Thiram (tetramethylthiuram disulfide)
is a previously registered active ingredient for use as a seed treatment
at 14.6% active ingredient by weight on soybeans. Raxil Thiram
Flowable Fungicide is used for seed treatment at a 20% application rate
(on a smaller seed thus more surface area).

The TS&LS has no objection to registration for this use only. However,
should Gustafson, Inc., apply for a major change in label to use
tebuconazole or thiram at a higher application rate or for field crops
or turf, a complete data package and technical review would need to be
completed.

After consideration of the reviews by NYSDOH, DFW&MR, TS&LS, and our
Pesticide Product Registration Sectiong the pesticide product Raxil
Thiram Flowable Fungicide (EPA Reg. No. 7501-151) containing 0.6%
tebuconazole and 20% thiram is hereby accepted for registration for use
in New York State as labeled.

Enclosed for your records are the stamped-accepted label and the
certificate of registration for the above product.

If you have any questions on this matter, please contact Maureen
Serafini, Supervisor of our Pesticide Product Registration Section, at
(518) 457-7446.

Sincerely,

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

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