UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

SEP 21 ZOl1 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile for Registration Review: Cymoxanil (129106) 

FROM: Leonard Y ourman, Plant Pathologist 

Biological Analysis Branch 

THRU: 

Katherine 

Science Information 

Stebbins, Biologist 

and Analysis 

~ 

Branch 

Derek Berwald, Economist () ....... r ~ lAA ...:p Economic Analysis Branch 'f' ' ~ Biological and Economic Analysis Divisio (7503P) 

Amet Jones, Chief 

Biological Analysis Branch 

Diann Sims, Chief ;{).1....n...,...c~~~v Science Information and Analysis Branch 

Timothy 

Economic 

Kiely, 

Analysis 

Chief 

Branch '-' 

~ J W\~ 

Biological and Economic Analysis Division 503P) 

TO: Moana Appleyard, Chemical Review Manager 

Pesticide Reevaluation Division (7508P) 

Product Review Panel date: September 14,2011 

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 cymoxanil, 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 

1 
Review teams by BEAD. The document is based on information and data available to BEAD as 

of August 2011. 

Cymoxanil is a locally systemic fungicide that penetrates plant tissue rapidly after application. 

The systemic characteristic allows for curative properties post-infection. Cymoxanil is in the 

chemical group cyanoacetamideoxime, which is listed as a Group 27 fungicide by the Fungicide 

Resistance Action Committee (FRAC). It is the only fungicide. of its chemical group. 

The specific mode of action or target site is unknown (FRAC, 2011). In general, cymoxanil is 

active on fungi that belong to the Peronosporales order and is mainly used to control late blight 

and other Phytophthora diseases, and downy mildews. 

USE SITES 

Cymoxanil is registered for use on potatoes, tomatoes, peppers; cucurbits, leafy vegetables 

(except Brassica group 4), bulb vegetables (bulb onion and green onion subgroup), grapes grown 

east of the Rocky mountains, caneberries (except in California), and hops (except in California). 

There are also Special Local Need (SLN) registrations for use on the following crops: spinach, 

cabbage, Swiss chard, and table beets when they are grown.for seed. In addition, there is a SLN 

registration for use for commercial seed treatment for peas intended for export. 

COMMON FORMULATIONS AND APPLICATION METHODS 

Cymoxanil is formulated as dry flowable and dust. One end-use product, Curzate® 60 DF, is 

used as a tank-mix with a protectant fungicide, such as a copper product. Another cymoxanilcontaining product is Tanos®, which includes 2S% cymoxanil and 2S% femoxadone. The third 

registered product is Evolve®, which is a potato seed-piece treatment containing 1 % cymoxanil, 

2.S% thiophanate-methyl, and 6% mancozeb. 

Cymoxanil may be applied as a seed treatment to potato seed pieces and also to peas (as seeds 

for export only). Seed treatments may be made using slurry or mist seed treatment equipment. 

Foliar applications may be made using ground, aerial, and chemigation equipment. 

USAGE 

Cymoxanil was registered for use on potatoes in 1998. Over the 1998-2010 timeframe, usage on 

potatoes was highest in 1998 and 2000 and has generally leveled off (Figure 1). Usage overall 

has increased since the addition of several new crops in 2004. For the most recent years of 2008-

2010, cymoxanil usage in agriculture (excluding seed treatments) averaged approximately 

SO,OOO pounds for 400,000 treated acres (Proprietary Data 2008-2010). Seed treatments were 

excluded throughout this analysis because usage data are only available for potatoes from 2009-

2010. However, as a general estimate, seed treatments on potatoes accounted for less than 3% of 

the total acre treatments to potatoes in 2009 and 2010. Cymoxanil is typically applied to foliage 

one time per year at a rate of 0.12 pounds AI per acre. 

2 
Fi e 1. Agricultural Cymoxamil Usage Pounds AI A lied 1998-2010 

60,000 

o 00 

en 

en 

.-t 

o 

o 

~ 

.-t 

o 

o 

N 

Source: Proprietary Data, 1998-2010 

N 

o 

o 

N 

rt'l 

o 

o 

N 

..,. 

o 

o 

N 

II') 

o 

o 

N 

\0 

o 

o 

N 

,.... 

o 

o 

N 

00 

o 

o 

N 

en 

o 

o 

N 

o 

.-t 

o 

N 

Other includes lettuce, squash, onions, watermelons, caneberries, cantaloupes, wine grapes, and spinach 

• Other 

• Peppers 

• Pumpkins 

• Tomatoes 

• Cucumbers 

• Potatoes 

During 2008-2010, the top crops in terms of total pounds of active ingredient applied were 

potatoes (49%), cucumbers (22%), tomatoes (8%), pumpkins (5%), and peppers (5%) (Figure 2). 

These crops were also the top in terms of the total acres treated. 

Peppers 

5% 

Tomatoes 

8% 

Source: Proprietary Data, 2008-2010 

Percent of Total Pounds AI A lied) 

49% 

Other crops (listed in order of ranking) includes: lettuce, squash, onions, watermelons, caneberries, cantaloupes, wine grapes, and 

spinach 

3 
The states with the most agricultural usage in terms of pounds AI applied are Michigan (19%), 

Washington (13%), Florida (11%), California (10%), Wisconsin (6%), and Idaho (5%) (Figure 

3). These states were also the top in terms of the total acres treated. 

Fi ure 3. States with Hi hest Use (Percent of Total Pounds AI A lied) 

Source: Proprietary Data, 2008-2010 

BIOLOGICAL ASPECTS RELEVANT TO CYMOXANIL 

Resistance management strategies are described on both the Curzate® and Tanos® labels. FRAC 

identifies cymoxanil having a low to medium risk of having resistance develop to it by a 

pathogen. Field resistance has not been reported, but some of cymoxanil's target pathogens, 

such as Phytophthora infestans (the cause of late blight of potato), are notorious for developing 

resistance to fungicides. The language of the cymoxanillabels attempts to address the potential 

of resistance development. The Curzate label states "DO NOT use Curzate® 60DF alone. 

Always tank-mix with a labeled rate of protectant fungicide." Tanos® attempts to reduce 

resistance development by including two active ingredients, cymoxanil and femoxadone (a 

quinone outside inhibiting-QoI) fungicide (FRAC Group 11). Because of the two active 

ingredients, for some crops there are additional target diseases on the label for Tanos than the 

label for cymoxanil as a single active ingredient product. Cymoxanil is the only Group 27 

fungicide registered and, therefore, it may playa role in integrated disease management and 

resistance management programs where different fungicide chemistries are useful. 

HISTORY OF BEAD ASSESSMENTS FOR CYMOXANIL 

There are no available prior BEAD assessments for cymoxanil. 

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INFORMATION THAT MAY BE USEFUL FOR FUTURE WORK ON CYMOXANIL 

Obtaining additional information on the following items would improve future BEAD 

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

review of this pesticide. 

-Usage data for hops (ex. total pounds applied, acres treated, typical use rates and number of 

applications) 

REFERENCES 

FRAC. 2011. Fungicide Resistance Action Committee. http://www.frac.info/frac/index.htm; 

http://www.frac.info/frac/publicationlanhangiFRA C%20Code%20List%2020 11-final. pdf 

(accessed September 8, 2011). 

Proprietary Data. 1998-2010. 

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