UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

MAY 25 2011

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

MEMORANDUM

SUBJECT: BEAD Chemical Profile for Registration Review: Amitrole: PC Code 004401

Kaitlin Rienzo-Stack, Biologist

Biological Analysis Branch J~

Jihad Alsadek, Economist ..J'

Science Information and Analysis Branch

Andrew Lee, Economist jJ.L.(. Economic Analysis Branch 'f"

Biological and Economic Analysis Division (7503P)

Amet Jones, Chief /1 k·\rta~,..- Biological Analysis Branch J/f}

Diann Sims, Chief A"""~QrI ' 6dl/~;1;~ Science Informatio~~alysi~ranch

Timothy Kiely. Chief fA_~ Economic Analysis Branch IIV\..

Biological and Economic Analys ivision (7 03 )

FROM:

THRU:

TO: Kaitlin Keller, Chemical Review Manager

Risk Management and Implementation, Branch 3

Pesticide Reevaluation Division (7508P)

Product Review Panel date: April 6, 2011

INTRODUCTION

The purpose ofthis document is to convey usage information and a broad overview ofthe pest

management roles of pesticides that are beginning to undergo registration review. The

anticipated audience consists ofthe team ofEPA staff currently evaluating the registration status

of amitrole, and eventually the general public. This document builds upon the data already

provided in the "Usage and Label Use Data Packages" that are also provided to Registration
Review teams by BEAD. The document is based on information and data available to BEAD as

ofMarch 30,2011.

Amitrole is a triazole herbicide. It was previously classified as a restricted use pesticide but that

designation was rescinded following mitigation measures and product and use cancellations.

While it is used internationally on orchards and other agricultural crops, there are no agricultural

use sites for amitrole registered by the US EPA. Weeds resistant to amitrole have been

documented in other countries but none are known ofin the United States at this time.

USE SITES

Agricultural Use Sites

There are no registered agricultural use sites for amitrole in the U.S.

Non-Agricultural Use Sites

• Industrial outdoor construction areas

• Outdoor buildings and structures

• Rights-of-way, fencerows, hedgerows

• Uncultivated areas, soils

• Paved private roads and sidewalks

COMMON FORMULATIONS AND APPLICATION METHODS

Amitrole is available as soluble powder, granular and pellet formulations. It is applied as a spray

using boom sprayer.

USAGE

Agricultural

There are no registered agricultural crops for amitrole.

Non-Agricultural

Less than 5 lbs. a.i. of amitrole are used annually on rights-of-way in California. This is the only

usage data currently available to EPA. for amitrole, See section "INFORMATION THAT

MAY BE USEFUL FOR BEAD'S FUTURE WORK ON AMITROLE" below for

information that could help improve the Agency's understanding of amitrole usage.

BIOLOGICAL ASPECTS RELEVANT TO AMITROLE

Amitrole is a triazole herbicide, classified as a Group F3 chemical by the Herbicide Resistance

Action Committee (HRAC 2009). There are 4 weed species with known, documented resistance

to Group F3 herbicides (Heap 2011). Ofthose, all 4 have known documented resistance to

amitrole specifically (Table 1). The absence ofincidents of amitrole-resistant weeds in the

United States in this table does not necessarily mean there are not any but rather that none are

known and/or documented at this time.
Table 1: Known, documented incidents ofweed resistance to amitrole

Common

Resistant Weed Name Incidents Years Locations Crop

Poaannua Putnualbluegrass 1 1983 Belgium orchards

Polygonum Prostrate

aviculare knotweed 1 1984 Belgium apple

Agrostis Creeping

stolonifera bentgrass I 1986 Belgium pears

1988, railways, roadsides,

Lolium rigidum Rigid ryegrass 1 2008 Australia vineyards

Source: Heap 2011

mSTORY OF BEAD ASSESSMENTS FOR AMITROLE

There are no BEAD assessments for amitrole ,

INFORMATION THAT MAY BE USEFUL FOR BEAD'S FUTURE WORK ON

"AMITROLE

Obtaining additional information on the following items would improve future BEAD

assessments of amitrole and may be required as part ofthe registration review ofthis pesticide.

Usage data are needed on the following non-agricultural sites:

• Industrial/Construction Areas (Outdoor)

• Non-agricultural Outdoor Buildings/Structures

• Non-agricultural Right-of-Way/Fencerows/Hedgerows

• Non-agricultural Uncultivated Areas/Soils

• Paved Areas (Private Roads/Sidewalks)

REFERENCES

Heap, I. 2011. The International Survey ofHerbicide Resistant Weeds. Accessed February,

2011. Available online at www.weedscience.com

Herbicide Resistance Action Committee. 2009. Classification ofHerbicides According to Site of

Action. Last updated 2009. Accessed February, 2011. Available online at;

http://www.hracglobal.com/Publications/ClassificationofHerbicideSiteofAction/tabid/222

lDefault.aspx

http://www.cdpr.ca.gov/docs/pur/purmain.htm. 2007-2009