UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

SEP 18 2013 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: Fenamidone (046679) 

FROM: 

THRU: 

Leonard 

Biological 

Yourman, 

Analysis 

Ph.D., 

Branch 

Plant Pathologist ,f 

'~ 

~ 

/ 

Jihad Alsadek, Ph.D., Economist ~ ~ Science Information and Analysis Branch 

Derek Berwald, Ph.D., Economist .t;( 

Economic Analysis Branch 1)-~M\~ Biological and Economic An~l 'sis Division (7503P) 

Arnet Jones, Chief 

Biological Analysis Branc 

Diann Sims, Chief M ~ .... ,_ 

Science Information and Analysis Branch 

Economic Analysis Branch (j 1~ Vv\ Timothy Kiely, Chief 4,. ~ 

Biological and Economic Analys~ Divis1 (7503P) 

TO: Christina Scheltema, Chemical Review Manager 

Risk Management and Implementation Branch 3 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel date: September 11,2013 
INTRODUCTION 

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

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

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

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

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

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

risk managers, and the general public during the registration review process of this pesticide. 

Fenamidone is one of several fungicides classified as Group 11 fungicides by the Fungicide 

Resistance Action Committee (FRAC, 2013). Group 11 fungicides as a class of fungicides have 

been important in disease management programs for a wide variety of crops since the first Qol 

product was registered in the late 1990s (Vincelli, 2012). Fenamidone is chemically classified as 

an imidazolinone in the group of quinone outside inhibitors (Qol) of electron transport. It is 

especially effective against species causing downy mildew of lettuce, spinach, onion, garlic, and 

cucurbits and Pythium spp. causing cavity spot of carrots. It also is used for managing 

Alternaria spp., certain rust species, late blight (Phytophthora infestans) and early blight 

(Alternaria so/ani) of potato and fruiting vegetables, and several other pathogens of the labeled 

crops. 

Fenamidone, like other Qol fungicides, exhibits translaminar movement through the plant leaf 

surface layers (Vincelli, 2012). This characteristic allows the chemical applied to one side of the 

leaf to travel through the leaf and bind to the cuticle on the other side, thus enhancing fungicidal 

protectant activity (especially inhibition of spore germination) even with incomplete spray 

coverage. Qol fungicides may have some degree of systemic activity to move throughout the 

plant's vascular system. Fenamidone has partial systemic activity with some movement in the 

plant and, therefore, has some curative as well as protective properties. 

USE SITES 

Registered agricultural use sites for the fungicide fenamidone include leafy vegetables (Brassica 

and non-Brassica), turnip greens, carrots, cotton, cucurbit vegetables, grapes, potatoes, various 

bulb/root/ tuberous/corm vegetables, tomatoes, peppers and some other fruiting vegetables, 

sunflower, tobacco and commercial greenhouse ornamentals. Fenamidone is registered for use 

as a seed treatment of sunflower and cotton. Fenamidone is not registered on non-agricultural 

sites. 

FORMULATIONS AND APPLICATION METHODS 

Fenamidone is formulated as an emulsifiable concentrate (EC). It is labeled to be applied as a 

foliar spray, as an in-furrow treatment, for application through chemigation, and by aerial 

application. 

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HISTORY OF FENAMIDONE AND BEAD PRODUCTS 

Fenamidone was initially registered in 2002, and therefore, did not go through a reevaluation 

during the Registration Eligibility Decision process. There were no reported usage data from 

2002 to 2004. A request in 2007 for a Section 18 Emergency Exemption for fenamidone to 

control cavity spot on carrots due to a loss of efficacy for mefenoxam was granted for California, 

Oregon, and Washington. 

A Screening Level Usage Analysis (SLUA) was prepared by BEAD (2013) for this chemical. 

The SLUA provides percent crop treated (PCT) for eleven crops. The SLUA shows the PCT of 

fenamidone to be mainly on carrots (20%), lettuce (15%), spinach (10%), garlic (10%), onions 

(10%), and cucumber (5%). Fenamidone is used to a lesser extent on the remaining crops 

(broccoli, cabbage, potatoes, tomatoes and watermelon). 

FENAMIDONE USAGE 

Usage Trends: 

2005-2011 

Usage of fenamidone, in both total areas treated (in acres) and total pounds in active ingredient 

applied, increased during this time period (Fig. 1). Approximately 23,000 pounds offenamidone 

were applied annually to 106,000 acres, at an average application rate of 0.2 lbs. a.i. per acre. 

200,000 .-------------------

Total Pounds 

Applied & Total 

Acres Treated 

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0 

0 

N 

Source: Proprietary Data, 2005-2011 

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0 

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...... co en 0 0 0 0 0 0 N N N 

Years 

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3 
Table 1 shows the percentage of total pounds applied and total acres treated (TAT) for the five 

crops with the greatest usage. Farmers may have been treating more acreage with the same 

overall average application rate of 0.2 lbs. a.i. per acre from 2008 to 2011. 

Table 1. Crops with Highest Use of Fenamidone- Percent of Total Pounds Active Ingredient 

Applied and Total Area Treated (TAT) in Acres, 2007-2011 

Crop % of Pounds Used %Total Acres Treated (TAT) Average% of Crop Treated 

Lettuce 47 45 15 

Carrots 21 19 20 

Potatoes 17 18 <2.5 

Onions 9 ll 10 

Spinach 4 4 10 

Source: Propraetary Data, 2007-2011 

California, Idaho, and Arizona are the top three states in terms of total poundage applied and 

total acres treated as shown in Table 2. 

Table 2. Comparison of States with Highest Use of Fenamidone- Percent of Total Pounds 

Applied and Total Area Treated (TAT) in Acres, 2007-2011 

State % of Pounds Used % Total Acres Treated (TAT) 

California 75 73 

Idaho 17 18 

Arizona 8 8 

Source: Proprietary Data, 2007-2011 

The average application rate for the top five crops ranges from 0.20 to 0.25 lbs a.i. per acre as 

shown in Table 3. The concentration of use in the states in Table 2 is consistent with the 

concentration of use in lettuce (California and Arizona), carrots (California), and potatoes 

(Idaho). 

T a e bl 3 F . enam1 "d one u se on T C op rops: A verage AIR .. ate, 2007 -2011 

Crop Average Annual Average Annual Acres Average AI Rate 

Pounds Used Treated (lbs. a.i./acres) 

Lettuce 13,000 58,000 0.22 

Carrots 6,000 25,000 0.24 

Potatoes 5,000 24,000 0.21 

Onions 2,000 14,000 0.14 

Spinach 1,000 5,000 0.20 

Source: Proprietary Data, 2007-2011 

CHEMICAL AND USE CHARACTERISTICS 

Fenamidone and other Qol fungicides (such as azoxystrobin, pyraclostrobin, and trifloxystrobin) 

inhibit fungal respiration in the fungal mitochondria (Vincelli, 2012). When Qol fungicides bind 

to a specific site in the pathogen it blocks electron transfer, which inhibits cellular respiration. 

Resistance occurs when a single base change (point mutation) in the cytochrome b gene results 

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in an amino acid change in one site of the resulting protein. This results in a change in protein 

structure, which alters the site where the fungicide binds to the fungus and, thus, prevents 

fungicidal activity. Depending on the site of the point mutation, a strong, moderate, or weak 

resistance to the fungicide can result. 

ROLE OF FENAMIDONE IN PEST MANAGEMENT 

Fenamidone is especially effective in managing downy mildew on lettuce (e.g., UC-Lettuce, 

2012; Raid and Sui, 2012), spinach (e.g., UC-Spinach, 2012), cucurbits (UC-Cucurbits, 2012), 

and onion and garlic (e.g., UC-Onion, 2008). Fenamidone is also widely used for managing 

cavity spot on carrot (e.g., UC-Carrot, 2012). Fenamidone is among the Qoi fungicides 

recommended for managing early blight and late blight of potato (e.g., Miller and Miller, 2005; 

UC-Potato, 2008; UC-Potato, 2007). 

The Group 11 fungicides have a wide spectrum of pathogen targets, but are considered generally 

at high risk for pathogens developing resistance (FRAC, 2013). In spite of some chemical 

differences among the different active ingredients that comprise Group 11 fungicides they are 

considered cross-reactive, and thus, are not alternatives to one another for disease management 

purposes. Because of resistance concerns for all Qoi fungicides they are usually alternated or 

tank-mixed with fungicides of different chemical groups. In addition, the number of applications 

per season is usually limited in order to reduce the likelihood that pathogens will develop 

resistance. 

DATA NEEDS 

• The Agency currently has usage data for several crops. However, obtaining usage 

information on several specialty crops listed on the label and greenhouse ornamental 

crops would improve future assessments conducted by the Agency related to the use and 

benefits of fenamidone. 

• Fenamidone appears to be used preferentially compared to other Qoi fungicides for 

managing downy mildew on several crops and cavity spot in carrots. Is there efficacy 

information on the use of fenamidone on other crops where fenamidone may be 

particularly effective and used preferentially to other registered fungicides? 

• Current labels specify maximum amounts of fenamidone to be used per acre "per 

growing season". In many cases this will be the maximum yearly use. However, there 

may be certain locations where a crop is grown sequentially in a single year, and thus, the 

current label may allow a greater amount of the fungicide per year than would be applied 

for single season crops. Therefore, information from the registrant that can identify 

situations where the use per year typically exceeds the growing-season maximum rate 

would be helpful for risk assessments of environmental concern. 

• Fenamidone is registered as a seed treatment for sunflower and cotton. BEAD has no 

data on these uses. Additional information would be useful to assess fenamidone benefits 

as a seed treatment. 

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REFERENCES 

BEAD. 2013. Fenamidone Screening Level Usage Analysis (SLUA). Biological and Economic Analysis 

Division (BEAD), Office of Pesticide Programs (OPP), US Environmental Protection Agency (USEPA). 

March 25,2013. 

FRAC. 2013. Fungicide Resistance Action Committee. FRAC Code List0 : Fungicides sorted by mode of 

action (including FRAC Code numbering). 

http://www. frac. info/publication/anhang/FRAC%20Code%20List%2020 13-update%20April-20 13 .pdf 

Miller, J. and Miller, T. 2005. Use of foliar fungicides for managing potato diseases. Idaho Potato 

Conference January 19-20, 2005. 

http://www.cals.uidaho.edu/potatoes/Research&Extension/Topic/Diseases/UseOfFoliarFungicidesForMa 

nagingPotatoDiseases-OS.pdf 

Raid, R.N. and Sui, D. D. 2012.Management oflettuce downy mildew with fungicides. Proceedings of 

the Florida State Horticultural Society 125:218-221. http://fshs8813 .wpengine.com/proceedings-x/20 12-

voi-125/FSHS vol 125/218-22l.pdf 

UC-Carrot. 2012. UC Pest Management Guidelines-Carrot Cavity Spot. University of California 

Extension. http://www .ipm. ucdavis.edu/PMG/r I 021 00411.html 

UC-Cucurbits. 2012. UC Pest Management Guidelines-Carrot Cavity Spot. University of California 

Extension http://www.ipm.ucdavis.edu/PMG/rll61 016II.html 

UC-Lettuce. 2012. UC Pest Management Guidelines-Lettuce Downy Mildew. University of California 

Extension. http://www.ipm.ucdavis.edu/PMG/r4411 00411.html 

UC-Onion. 2008. UC Pest Management Guidelines-Onion and Garlic Downy Mildew. University of 

California Extension. http://www.ipm.ucdavis.edu/PMG/r584100III.html 

UC-Potato. 2008. UC Pest Management Guidelines-Potato Late Blight. University of California 

Extension. http://www .ipm.ucdavis.edu/PMG/r6071 0 1211.html; 

UC-Potato. 2007. UC Pest Management Guidelines-Potato Early Blight. University of California 

Extension. http://www.ipm.ucdavis.edu/PMG/r60710131l .html 

UC-Spinach. 2012. UC Pest Management Guidelines-Spinach Downy Mildew. University of California 

Extension. http://www.ipm.ucdavis.edu/PMG/r7321001Jl.html 

USDA, 2007. Census of Agriculture. http://www.agcensus.usda.gov/Publications/2007/index.asp. 

Vincelli, P. 2012 (updated). Qol (Strobilurin) Fungicides: Benefits and Risks. The Plant Health Instructor. 

DOl: 10.1094/PHI-1-2002-0809-02, 2002, updated 2012. 

http://www.apsnet.org/edcenter/advanced/topics/Pages/StrobilurinFungicides.aspx 

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