UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

FEB 06 2012 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

SUBJECT: BEAD Chemical Profile for Registration Review: Dichlobenil (027401) 

FROM: Monisha 

Biological 

Kaul, 

Analysis 

Biologist 

Branch 

fYlOiuo W I~ 

Rafael 

Science 

Prieto, 

Information 

Environmental 

and Analysis 

Protection 

Branch 

Specialist 

II 

~ "I -'-I A' f ~ 

THRU: 

TO: 

John Faulkner, Economist UN! v1 nl 

Economic 

Biological 

Analysis 

and Economic 

Branch 

Analysis 

(J'I.TI 

Division 

v, I 

(7503P) 

~ 

Arnet Jones, Chief 

Biological Analysis Branch 

Diann Sims, Chief ;{}L~ ~ Science Information and Analysis Branch 

Timothy Kiely, Chief 

~~ ~ 

Economic Analysis Brancn0 

Biological and Economic Analysi ivision (7503-P) 

Eric Miederhoff, Chemical Review Manager 

Risk Management and Implementation Branch 3 

Pesticide Re-evaluation Division (7508-P) 

Product Review Panel date: December 7, 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 

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

of dichlobenil, 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 

of November 22,2011. 

Dichlobenil is a pre-emergent herbicide registered to control grasses and broadleaf weeds on a 

variety of use sites. Dichlobenil acts by inhibiting cell wall synthesis. It is classified by 

Herbicide Resistance Action Committee as Group L and by the Weed Science Society of 

America (WSSA) as Group 20 or a nitrile (WSSA, 2011). 

USE SITES 

Agricultural Use Sites 

The registered agricultural use sites for dichlobenil include apples, grapes, cherries, caneberries, 

blueberries, pears, plant nurseries, shelterbelts, nut trees, and various other crops such as filberts, 

huckleberries, laurel, rhubarb, and strawberries. 

Non-Agricultural Use Sites 

The registered non-agricultural use sites for dichlobenil: In and around ornamental plantings, 

drain lines, drains, irrigation supply systems, sewage system, waste water systems, sewer lines, 

cesspools, storm sewers; non-crop areas, military installations, buildings, roadways, rights-ofway, roadsides, roadways, parkways, rail yards, industrial sites, asphalt paving, parking lots, 

walks, driveways, parking areas, pre-paving treatment, sidewalks, paved areas, fencerows, and 

vinyl swimming pool liners. 

COMMON FORMULATIONS AND APPLICATION METHODS 

Dichlobenil is formulated as microencapsulated, wettable powder, granular, water soluble 

packages, and soluble concentrate. 

USAGE 

Agricultural Usage 

Based on limited private market pesticide usage data, dichlobenil annual agricultural usage 

averaged 5,000 pounds of active ingredient (A.I.) treating an average of2,000 acres for the years 

2001-2010 for an overall average of 2.5 pounds per acre. 

Because limited data are available for dichlobenil, BEAD is unable to provide accurate details as 

to this chemical's major crops, main states where this chemical is used, or generate a trend by 

crop analysis. However, using the available data, we were able to generate a graph (Figure 1), 

depicting total pounds AI of dichlobenil (Proprietary data, 2001-2010). This figure illustrates a 

wide variance in this chemical's reported usage. 

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Fi e 1. Total A ·cultural Usa e ofDichlobenil for Years 2001-2010. 

12,000 .....--------------------------

.... 

8 

N 

N 

8 

N 

m 

o 

o 

N 

Source: Proprietary data, 2001-2010. 

Non-agricultural usage 

¢ 

8 

N 

.n 

o 

o 

N 

Year 

\Q 

o 

o 

N 8 " N 

00 

o 

o 

N 

en 

o 

o 

N 

o 

.... 

o 

N 

Based on the data available to BEAD, it appears that dichlobenil has more non-agricultural usage 

than agricultural usage. According to KLINE and Company data, this chemical's usage in golf 

courses has jumped from 58 pounds AI in 1999 to 426 in 2006. On turf and landscape, this 

chemical's usage fluctuated. For lawn care operators, usage has significantly declined from 

1999 to 2006. On Nursery/greenhouse, usage has generally been increasing from 1999 to 2006. 

Kline Segment 1999 2002 2004 2006 

(LbsAl) (LbsAl) (LbsAl) (Lbs AI) 

Golf Courses 58 - - 426 

Institutional Turf 17,880 4,408 3,415 9,881 

Landscape 1,598 13,824 494 2,551 

Lawn Care Operators 16,056 1,422 - 612 

Nurse,ry/Greenhouse 2,452 3,206 2,492 4,024 

Data are not avrulable 

Source: KLINE and Company Inc., 1999,2002,2004, and 2006. 

Additional data were obtained from California Department of Pesticide Regulation (DPR) 

because of the limited data on dichlobenil available to BEAD. Rights of way and sewage 

systems are the top two uses in California, with an average of approximately 9,500 pounds AI for 

rights of way, and 8,400 pounds AI for sewage systems. 

(California DPR, 2008-2010) 

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BIOLOGICAL ASPECTS RELEVANT TO DICHLOBENIL 

There are no reports of weed resistance to dichlobenil in the U.S. (HRAC, 2011). 

There have been shifts in use of dichlobenil as shown in Figure 1. Research has indicated that 

some growers may be concerned about crop damage as a result of repeated use of dichlobenil 

(Sandler, et al., 2004). Approved section 18 emergency exemption use of mesotrione to replace 

dichlobenil also indicates shifts in grower needs around 2004 through 2006. However, according 

to Sandler et al. (2004), research studies on the phytotoxicity of dichobenil have had mixed 

results. Pre-emergent herbicides other than dichlobnil are used on more crop area for weeds 

commonly targeted by dichobenil such as dandelion, orchardgrass, and quackgrass (proprietary 

data,2001-2010). Further research is required to determine the needs of dichlobenil for specific 

crops and pests. 

mSTORY OF BEAD ASSESSMENTS FOR DICHLOBENIL 

Mesotrione was requested as an emergency exemption (2004-06) for use on cranberries because 

the registered alternative, dichlobenil, causes crop phytotoxicity and permanent loss of long-term 

productivity with continued use at the maximum rates. 

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

DICHLOBENIL 

Obtaining additional information on the following items would improve future BEAD 

assessments of the importance of dichlobenil and may be required as part of the registration 

review of this pesticide: pounds AI, area treated, typical application rates by crop/site for both 

agricultural and non-agricultural uses. 

REFERENCES 

California DPR, 2008-2010. Online: http://www.cdpr.ca.gov/docs/pur/purmain.htm. 

KLINE and Company Inc., 1999,2002,2004, and 2006. 

Proprietary data, 2001-2010. 

RED (Reregistration Eligibility Document): http://www.epa.gov/oppsrrd1IREDs/0263red.pdf. 

Sandler, H.A., J. Manson, W. R. Autio, T. A. Bewick, 2004. Effects of repeat annual 

applications of dichlobenil on weed populations and yield components of cranberry. Weed 

Technology, 18(3):648-657. 

WSSA, 2011. Cellulose inhibitors (L/27) resistant weeds. Online: 

http://www. weedscience.org/Summary/UspeciesMOA.asp?lstMOAID= 19. Verified: October 

11,2011. 

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