UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OCT 1 2 2011 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile for Registration Review: Halosulfuron-methyl (128721) 

FROM: 

THRU: 

TO: 

Sunil Ratnayake, Biologist 

Biological Analysis Branch 

Jihad Alsadek, Economist 

Science Information and Analysis Branch 

Economic 

StephenSmearman,Economist 

Analysis Branch !btJI( 

1, _ ..... 

/ 

~~ 

Biological and Economic Analysis Division (7503P) 

Arnet 

Biological 

Jones, 

Analysis 

Chief 

Branch 

~~ . U 

Diann 

Science 

Sims, 

Information 

Chief 

and 

j)Analysis ~ Branch ~ 

Timothy Kiely, Chief . \A A 

Biological and Economic ~ Division (750 

Economic Analysis Branch vV'\... 

Kaitlin Keller, Chemical Review Manager 

Risk Management and Implementation Branch 3 

Pesticide Reevaluation Division (7508P) 

Product Review Panel date: Sep. 07, 2011 

INTRODUCTION 

The purpose of this document is to convey usage information and a broad overview of the pest 

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

anticipated audience consists of the team of EPA staff currently evaluating the registration status 

of halo sulfur on-methyl (128721), 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 infonuation and data available 

to BEAD as ofSep. 07,2011. 

Halosulfuron-methyl belongs to the sulfonylurea herbicide family and it inhibits the activity of 

acetolactate synthase enzyme which is important for synthesis of branched chain amino acids 

(leucine, isoleucine, and valine). Halosulfuron-methyl is a post-emergence herbicide and it is 

applied after emergence of target weeds. This herbicide has a greater selectivity at very low 

rates and generally recommended for the control of annual and perennial sedges. 

USE SITES 

Agricultural Use Sites 

Halosulfuron-methyl is applied for weed control in nut crops, ornamentals, field crops, vegetable 

crops, forage crops and turf. 

Non-Agricultural Use Sites 

Recreational areas, race tracks, non-crop areas, tennis courts, play grounds, right of way areas, 

and in golf courses. 

COMMON FORMULATIONS AND APPLICATION METHODS 

Halosulfuron-methyl is fonuulated as water dispersible granules and emulsifiable, flowable and 

soluble concentrates 

USAGE 

Agricultural 

From 2008-2010, the annual total agricultural usage averaged approximately 30,000 pounds 

active ingredient for 1,000,000 treated acres. During this time frame, the crops with the most use 

in tenus of total pounds of active ingredient applied are rice (53%), com (19%), sugarcane (7%) 

and green beans (4%). These crops also have the highest total area treated (TAT) for this 

timeframe. 

On average, the states with the most agricultural usage in tenus of pounds a.i. applied are 

Arkansas (23%), Louisiana (17%), Texas and Florida (9% each), and Wisconsin (7%). 

(Proprietary Data, 2008-2010). 

2 
USE TRENDS 

Figurel provides usage trends in terms of pounds active ingredient applied. The use of 

halosulfuron-methyl on green beans was stable during the years 2008-2010. The use on com, 

rice, and other cropsl increased during this time frame. Use on sugarcane was stable from 2008-

2009 and there was a significant decline in use in 2010. 

Figure 1. Halosulfuron-methyl Agricultural Usage Data, 2008-2010 

45,000 ..,----------------------

• Green Beans 

PoundsA.I. • Corn 

• Rice 

• Sugarcane 

• Other 

o 

2008 2009 2010 

Years 

Source: 

Proprietary Data, 2008-2010 

IOther crops include cucumber, dry beans, and soybeans (3% each), pumpkins and watermelons (2% 

each), and tomatoes, fallow, sweet corn, and squash (1 % each). 

3 
Figure 2 sho.ws the lo.ng tenn use o.fhalo.sulfuro.n-methyl fro.m 1998-2010. Halo.sulfuro.n-methyl 

was fIrst registered in May1985. In general usage has fluctuated o.n all crops thro.ugho.ut this 

timeframe. Fro.m 1998 - 1999, usage was primarily o.n co.rn, rice, and o.ther crops. 

Figure 2. Halosulfuron-methyl Long Term Agricultural Usage Data, 1998-2010 

70,000 

PoundsA.I. 

o 

Source: 

~ ~ ~ ~ ~ 0 M N m ~ ~ ~ ~ 

~ ~ 0 0 0 0 0 0 0 0 ~ ~ 0 0 0 0 0 0 0 0 M M N N N N N N N N 

Years 

Proprietary Data, 1998-2010 

Non-Agricultural 

• Green Beans 

• Corn 

• Rice 

• Sugarcane 

1 J j • Other 

The use o.fhalo.sufuro.n-methyl in go.lf co.urses increased from less than 500 lbs. a.i. in 2002 to. 

2,000 lbs. a.i. in 2004 and then declined to. 1,000 lbs. a.i. in 2006. Fo.r turffanns, use was almo.st 

1,000 lbs. a.i. in 2004 and 2006. There was less than 500 lbs. a.i. used o.n institutio.nal turf and 

fo.r landscape in 2004 and 2006. Lawn care o.perato.rs (LeOs) used less than 500 lbs. a.i. o.f 

halo.sulfuro.n-methyl in 2002 and 2004, and abo.ut 3,000 lbs. a.i. in 2006. 

Kline and Company, Inc. 2002-2006 

BIOLOGICAL ASPECTS RELEVANT TO HALOSULFURON-METHYL 

Halo.sulfuro.n-methyl belo.ngs to. the sulfo.nylurea herbicide family which inhibits the activity o.f 

acetolactate synthase enzyme (ALS) and presence o.f 44 weed species resistant to. ALS inhibito.rs 

has been repo.rted in the United States (Heap et al. 2011). Ho.wever, no. repo.rts co.uld be fo.und o.n 

develo.pment o.f weed resistance, specifIcally to. halo.sulfuro.n. Herbicide injury: in so.ybean due to. 

o.ff-site mo.vement o.f halo.sulfuro.n has been repo.rted as a result o.f halo.sulfuro.n applicatio.ns in 

rice fIelds in Mississippi (Nandula et al., 2009). 

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mSTORY OF BEAD ASSESSMENTS FOR HALOSULFURON-METHYL 

Seven Section 18 requests for halosulfuron-methyl have been reviewed by BEAD since 2001. 

The requests for halosulfuron-methyl were to control nutsedge, pigweed and other broad leaf 

weeds because other herbicides used on these crops did not provide adequate control. The 

following is a list of the Section 18' s requested by year and the use site. 

01-WA-21: DP Barcode (273883) - Review of Request for Emergency Exemption of 

Halosulfuron-methyl (Sandea) in Washington, Oregon & Idaho for Use on Asparagus to Control 

Yellow Nutsedge. BEAD determined that the situation was urgent and non-routine. 

01-MI-12; DP Barcodes (D274633, D274635) - Review of Request for Emergency Exemption of 

Halosulfuron-methyl (Sandea) in Michigan for Use on Asparagus to Control Yellow Nutsedge 

and PS II resistant, Redroot Pigweed. BEAD determined that the situation was urgent and nonroutine. 

01-CA-0038; DP Barcode (D278475 & D278474) - Review of Request for Emergency 

Exemption of Halosulfuron-methyl (Sandea) in California for Use on Asparagus to Control 

Yellow Nutsedge. BEAD determined that the situation was urgent and non-routine. 

02-FL-07; DP Barcode (D281476) - Review of Request for Emergency Exemption for Use of 

Halosulfuron-methyl (Sandea) to Control Nutsedge in Tomatoes in Florida. BEAD determined 

that the situation was urgent and non-routine because methyl bromide was being phased out. 

04-MS-00I0; DP Barcode (D301955) - Review ofa Request for Emergency Exemption of 

Halosulfuron in Mississippi and Louisiana for Use on Sweet Potatoes to Control Purple 

Nutsedge. BEAD determined that the situation was urgent and non-routine. 

04-LA-0007; DP Barcode (D301958) - Review of a Request for Emergency Exemption of 

Halosulfuron in Mississippi and Louisiana for Use on Sweet Potatoes to Control Purple 

Nutsedge. BEAD determined that the situation was urgent and non-routine. 

04-NC-0009; DP Barcodes (D303202 and 343705) - Review of a Request for Emergency 

Exemption of Halosulfuron in North Carolina for Use on Sweet Potato to Control Purple 

Nutsedge. BEAD determined that the situation was urgent and non-routine. 

The Section 18 requests found in the BEAD data base suggest that there were benefits to using 

halosulfuron-methyl to control nutsedge and pigweed in asparagus, sweet potatoes, and 

tomatoes. 

In addition the Section 18s there were numerous benefits assessments for methyl bromide across 

a wide range of crops for numerous weed species in which halosulfuron-methyl was considered ' 

as one of the alternatives to methyl bromide because at the time, methyl bromide was being 

phased out. 

5 
DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON HALOSULFURONMETHYL 

Obtaining additional infonnation on the following items would improve future BEAD 

assessments of the importance of halo sulfur on-methyl and may be required as part of the 

registration review of this pesticide. 

Airports, grounds (all), fallow, fann storage areas, tank fanns, 

industrial/commercial/recreational, lumber, race tracks, fencerows, right-of-way, roadsides, 

schools, and tennis courts. 

REFERENCES 

Heap, I, H. Glick, L Glasglow, and W. Vencill. 2011. Herbicide Resistant Weeds by Country 

and Site of Action. 2011. http://www.weedscience.org/summary/countrysummary.asp 

Proprietary Data, 1998-2010 

Kline and Company, Inc. 2002-2006 

Nandula, V. K., Poston, D. H., Reddy, K. N. and K. Whiting. 2009. Response of Soybean to 

Halosulfuron Herbicide. Int. Journal of Agronomy. Volume 2009, Article ID 754510 

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