UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

APR 15 2014 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: Etridiazole (PC 084701) 

FROM: 

THRU: 

TO: 

Leonard Y ourman, Plant Pathologist ~~...c,...-'"1~..__;........---..-­ Biological Analysis Branch 

Rafael A. Prieto, Environmental Protection Specialist ~~ 

Science Information and Analysis Branch 

Stephen Smearman, Economist 

Economic 

Biological 

Analysis 

and Economic 

Branch 

Analysis Div

~~ ision (7503P) 

Amet Jones, Chief 

Biological Analysis Branco 

Diann 

Science 

Sims, 

Information 

Chief ~ and Analysis Branch 

Timothy 

Economic KielyAnalysis , Chief Branch 

Sl \;\A ~ Biological and Economic Analysis ivision (750 ) 

Margaret Hathaway, Chemical Review Manager 

Risk Management and Implementation Branch 4 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel date: March 19, 2014 
INTRODUCTION 

The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an 

overview of the pest management roles and quantitative usage information for etridiazole. The 

BCP includes summaries of previous BEAD products and available public and/or private use and 

usage data for etridiazole to describe the role of this chemical in pest management. Additional 

information on use is available in the etridiazole PRD Label Data Report. Information provided 

in this BCP may be used by stakeholders (e.g., users and registrants), OPP risk assessors, and 

OPP risk managers, and the general public during the Registration Review process of this 

pesticide. 

USE SITES 

According to BEAD information sources, cotton is the only agricultural crop for which 

etridiazole is used. Etridiazole (Terrazo le~ has a federal registration for use on ornamentals, 

golf course turf, nursery stock, cotton, and tobacco. In addition, there are several states with 

Special Local Need (SLN) 24c labels for use in greenhouse tomato production. 

FORMULATIONS AND APPLICATION METHODS 

This chemical is formulated as a wettable powder, emulsifiable concentrate, soluble concentrate 

(liquid), and granular. 

HISTORY OF ETRIDIAZOLE and BEAD PRODUCTS 

Etridiazole was registered for use in the U.S. in 1962, for control of damping-off, root rot and 

stem rot caused primarily by species of Pythium. A Screening Level Usage Analysis (SLUA) 

was prepared by BEAD for this chemical in 2014 that provides percent crop treated for cotton for 

which usage data was available. Use for cotton over the SLUA timeframe (1998-2011) 

accounted for l 00% of the agricultural etridiazole usage. However this usage represents only 

1.2% crop treated for cotton harvested acres, which may mean low benefits overall to cotton 

growers. However, uses limited to certain cotton production locations might indicate some 

useful attributes of etridiazole, although BEAD does not have supporting information for this 

possibility. 

A search of the BEAD data base found that there are no records of prior BEAD benefits 

assessments or emergency exemption requests for etridiazole. Note that a lack of emergency 

exemption requests for BEAD to review as part of the emergency exemption process for this 

chemical does not specifically indicate the importance of the chemical. 

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USAGE 

Usage Trends 

For the years 1998-2012, etridiazole annual agricultural usage averaged 23,000 pounds of active 

ingredient (a.i.) treating an average of 126,000 acres, for an overall average application rate of 

0.1825 pounds a.i. per acre. Use in terms of both pounds a.i. and total area treated peaked in 

2000, and has been steadily declining until the most recent years for which data are available 

(Proprietary data, 1998-2012). 

Fi ure 1. Etridiazole Total Pounds and TAT in Acres on Cotton 1998-2012 

0 00 0\ 0 .-4 N m ~ IJ) \0 ,.... 00 0\ 0 .-4 N 0\ 0\ 0 0 0 0 0 0 0 0 0 0 .-4 .-4 .-4 0\ 0\ 0 0 0 0 0 0 0 0 0 0 0 0 0 .-4 .-4 N N N N N N N N N N N N N 

Year 

Source: Proprietary Data, 1998-20 12. 

70,000 

0 

- TAT (acres) 

...... LbsAI 

Based on proprietary data, 100 percent of etridiazole use is on cotton. This chemical's usage 

both in terms of total pounds and total area treated are in decline. 

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Table 1. Comparison of States with Highest Use ofEtridiazole on Cotton- Percent of Total 

Lb s. A ,pplie r dB etween t h e 1998 -2002 an d 2008 2012 - T' 1me f rames 

1998-2002 2008-2012 

State %Lbs State %Lbs 

Mississippi 32 Miss.issippi 51 

Louisiana 19 North Carolina 27 

Tennessee 13 Texas 22 

Arkansas 12 

Alabama 8 

North Carolina 7 

Texas 6 

Source: Propnetary Data, 1998-2012. 

Application Rates 

T a e bl 2 . Et ri . d. 1azo I e U se on c otton: A verage p oun d s, TAT , an dAIR . . ate 

Years Average Pounds Average Total Acres Treated Avg. AI Rate 

(TAT)* (lbs a.i./acres) 

1998-2002 47,000 252,000 0.186 

2008-2012 800 4,000 0.188 

*Total Acres Treated sums all acres treated for a crop, mcludmg those acres that recetve multtple treatments. 

Source: EPA Proprietary Data, 1998-2012 

Non-Agricultural Usage 

BEAD information indicates 14,000 lbs etridiazole used on U.S. turf and ornamental uses for 

2012. (EPA Proprietary Data, 2012) 

ROLE OF ETRIDIAZOLE IN PEST MANAGEMENT 

Etridiazole is a thiadiazole fungicide, classified by FRAC as a Group 14 fungicide (FRAC, 

2013). The mode of action has not been definitively identified, although FRAC information 

indicates that it may work by damaging cell membranes through lipid peroxidation (FRAC, 

2013). Etridiazole may be used to treat soil in-furrow prior to planting cotton, especially where 

cotton has been planted year after year and where damping-off is known to be a problem. It is 

also used to treat tobacco transplants in greenhouse or outdoor float-bed systems. Etridiazole is 

used to manage the soil borne pathogen Pythium spp., which causes damping off and root rot of 

seedlings. It acts as a protectant contact fungicide and may have curative properties against 

Pythium for tobacco transplants. Several SLN labels are in effect to treat Pythium root rots in 

greenhouse tomato production. Mefenoxam may be used similarly to manage Pythium dampingoff for soil and transplant treatments and seed treatments with metalaxyl or azoxystrobin may be 

used to protect against damping-off. Many soil and seed treatments contain additional active 

ingredients to manage other important pathogens such as Fusarium spp. 

DATA NEEDS 

The Agency currently does not have extensive information on etridiazole. Obtaining information 

may be useful for non-agricultural sites. In addition, information on specific attributes of 

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etridiazole, for example on cotton, may improve future benefits or impact assessments if risk 

issues are found to exist. 

REFERENCES 

FRAC. 2013. List of Plant Pathogenic Organisms Resistant to Disease Control Agents. 

Fungicide Resistance Action Committee. 

http://www.frac.info/publication/anhang/List%20of0/o20resistant%20plant%20pathogenic 

%20organisms February%202013%20updated.pdf 

EPA Proprietary Data, 2012. 

Proprietary Data. 1998-2012. 

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