UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OCT 25 2011 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile for Registration Review: Chlorothalonil (PC #081901) 

FROM: Leonard Y ourman, Plant Pathologist A 

Biological Analysis Branch If / ( 

Jihad Alsadek, Economist J t/ t.-J ~ Science Information and Analysis Branch 

Michelle Ranville, Economist I h f c-fJ 

Economic Analysis Branch \.\ \}J JU .../ 

Biological and Economic Analysis Division (7503P) 

THRU: Arnet Jones, Chief /I L1 

Biological Analysis Branch ~' i 

Diann Sims, Chief ~ ..... ~.A..J' Science Information and Analysis Branch ~ 

Timothy Kiely, Chief ~ tV\A. \. 

Economic Analysis Branch \.,.: J _ ~ Biological and Economic Analysis Division (7503P) 

TO: Jill Bloom, Chemical Review Manager 

Risk Management and Implementation Branch 2 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel date: September 21, 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 

ofchlorothalonil (PC Code 081901), and eventually the general public. This document builds 

upon the data already provided in the "Usage and Label Use Data Packages" that are also 

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.provided to Registration Review teams by BEAD. The document is based on infonnation and 

data available to BEAD as of May, 2011. 

Chlorothalonil is a widely used non-systemic fungicide that targets numerous fungal pathogens 

of many crops. It is a preventative treatment used to protect the plant that is applied prior to 

infection when there is an expectation that pathogens may soon be present and where conditions 

are likely to be conducive to disease development. Chlorothalonil is a chloronitrile chemical that 

targets multiple sites of the fungal pathogen upon contact (FRAC, 2011). As such, field 

resistance to it has not been found. It is commonly used alone or mixed with another active 

ingredient (frequently systemic, single-site of action fungicides) to treat numerous diseases 

including (depending on the crop) Alternaria, anthracnose, Botrytis, Cercospora, downy mildew, 

rust, Septoria, and others. 

USE SITES 

According to the LUIS report (May 18,2011), uses for chlorothalonil include: 

Agricultural Use Sites 

Chlorothalonil is labeled for use on many food crops including: almonds, apples, apricots, 

asparagus, barley, numerous bean crops, cole crops, cucurbitlmelon crops, mint, onions, okra, 

peanuts, peppers, stone fruit crops, potatoes, tomatoes, walnuts, and wheat. 

Non-Agricultural Use Sites 

Chlorothalonil is labeled for use on many ornamental plants (both foliar and bulbs), numerous 

turf grass species, and forest nursery trees. 

Chlorothalonil is also labeled for use on various industrial and building products including 

adhesives, coatings, concrete blocks and surfaces, emulsions, grouts, irrigation systems, lumber, 

paints, plaster, polishes, stains, stucco, construction timber, and wood building materials. 

COMMON FORMULATIONS AND APPLICATION METHODS 

Chlorothalonil is fonnulated in solid fonn as dust, water dispersible granules, pellets, tablets, 

impregnated material, and wettable powder. In liquid fonn it is available as emulsifiable, 

flowable, soluble concentrate and also as a solution ready-to-use. There are several premix 

products containing chlorothalonil with one or more additional active ingredients. 

USAGE 

Agricultural 

Based on private market pesticide usage data from 1998-2010, the annual total agricultural usage 

averaged approximately 9 million lbs active ingredient for 8 million treated acres for an overall 

application rate of 1.1 lbs a.i. per acre. 

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From 1998-2010, the crops with the most use in terms of pounds a.i. applied are peanuts (37%), 

potatoes (26%), and tomatoes (8%). The crops with the most total area treated (TAT) are 

peanuts (42%), potatoes (31 %), and tomatoes (6%). 

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

Georgia (25%), Florida (13%), California (9%), Michigan (8%), and Alabama (7%) 

(Proprietary Data, 1998-2010). 

USE TRENDS 

Figure 1, Agricultural Use of Chlorothalonil, presents usage data in terms of total pounds a.i. 

applied on peanuts, potatoes, tomatoes, and other crops during 1998-2010. The overall use of 

chlorothalonil has remained fairly constant during this time frame. 

Fi ure 1. A ricultural Use of Chlorothalonil, 1998-2010 

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

• Other Crops 

PoundsA.I. 

• Tomatoes 

• Potatoes 

• Peanuts 

Years 

Note: Crops with the highest use in "Other crops" includes watermelons and cherries 

(4% each), and onions and cucumbers (3% each). 

Source: Proprietary Data, 1998-2010 

Non-Agricultural 

As shown in Table 1, the highest use of chlorothalonil is on golf courses, with approximately 3 

million lbs a.i. per annum being used during the reported years. Consumers used about one 

million lbs a.i. annually for the years 2000,2003, and 2005. Use on institutional turf increased 

from 32,000 lbs a.i. in 2002 to 164,000 lbs a.i. in 2006. The use of chlorothalonil on landscapes 

and turf farms fluctuated during the reported years while use for nurseries and green houses 

declined from 2002-2006. Lawn Care Operators' (PCOs) use of chlorothalonil was 

approximately 100,000 lbs a.i. on an annual basis from 2002-2006. Non-agricultural use of 

chlorothalonil is approximately 4.3 million lbs per year. 

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Table 1. N A . on- .. gncu I tura I U se 0 fChl orot h I aODl, '1 2000 2006 - Segment Year Pounds A.I. 

Consumer 2000 800,000 

2003 1,050,000 

2005 649,000 

Golf Courses 2002 2,795,000 

2004 2,988,000 

2006 2,724,000 

Institutional Turf 2002 32,000 

2004 138,000 

2006 164,000 

Landscape 2002 11,000 

2004 29,000 

2006 5,000 

Lawn Care 2002 124,000 

Operators 2004 132,000 

2006 112,000 

Nursery/Greenhouse 2002 416,000 

2004 168,000 

2006 89,000 

Turf Farms 2002 41,000 

2004 174,000 

2006 104,000 

Source: Kline and Company, 2000-2006 

BIOLOGICAL ASPECTS RELEVANT TO CHLOROTHALONIL 

Because of the multi -site mode of action, chlorothalonil is not prone to resistance development 

by pathogens. It is frequently used in resistance management programs as a tank-mix partner or 

a fungicide that is alternated with site-specific fungicides that are at risk for pathogen resistance 

development. 

HISTORY OF BEAD ASSESSMENTS FOR CHLOROTHALONIL 

BEAD reviewed numerous requests for emergency exemptions over many years for 

chlorothalonil use on ginseng in Wisconsin and Michigan to manage Alternaria stem and leaf 

blight, Botrytis blight, and/or Phytophthora leaf blight. Emergency claims were based on the 

lack of registered protectant (contact) fungicides for ginseng to manage foliar diseases during the 

growing season. According to the Office of Pesticide Programs Information Network (OPPIN) 

chlorothalonil became available for use on ginseng under a Section 3 label in 2009. 

There was also one Section 18 request for use of chlorothalonil on oranges in California in 2010 

(Chen and Smearman, 2010), but it was due to unusual weather conditions and is not likely to 

indicate an ongoing benefit of the chemical. 

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DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON CHLOROTHALONIL 

Obtaining additional infonnation on the following items would improve future BEAD 

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

review of this pesticide: 

• Usage data (lbs per year) for paints/adhesives/caulking/coating, 

commercial/institutional/industrial buildings, composition board and concrete surfaces, 

food handling establishments (FREs), and lumber/timber/wood 

• The importance of these uses, i.e., economic consequences of not having the chemical for 

these uses 

REFERENCES 

Chen, C. and Smearman, S. 2010. Review of Section 18 Submission from California for an 

Emergency Exemption for the Use of Chlorothalonil on Oranges to Control Septoria Spot, 

Septaria citri (10CAOl; DP #371948) 

FRAC. 2011. Fungicide Resistance Action Committee. FRAC Code List©: Fungicides sorted by 

mode of action (including FRAC Code numbering). 

http://www.frac.info/frac/publicationianhang/FRAC%20Code%20 List%2020 II-final. pdf 

(Accessed 14 Sept. 2011) 

Kline and Company, 2000-2006 

Proprietary Data, 1998-2010 

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