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 Yourman, Ph.D., Plant Pathologist 

# ,f**~** Biological Analysis Branch**'~** 

### / 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)

ProductReview Panel date: September 11,2013

### INTRODUCTION The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an overview ofthe pest management roles and quantitative usage information for fenamidone. The BCP includes summaries ofprevious BEADproducts and available public and/or private use and usage data for fenamidone to describe the role ofthis chemical in pest management. Additional information onuse is available inthe fenamidone PRD Label DataReport. Informationprovided in this BCP maybe usedby stakeholders (e.g., users and registrants), OPP risk assessors, OPP risk managers, and the general public during the registration reviewprocess ofthis pesticide. Fenamidone is one ofseveral fungicides classified as Group 11 fungicides by the Fungicide Resistance Action Committee (FRAC, 2013). Group 11 fungicides as a class offungicides have been important in disease management programs for a wide variety ofcrops since the first Qol product was registered inthe late 1990s (Vincelli, 2012). Fenamidone is chemically classified as an imidazolinone in the group ofquinone outside inhibitors (Qol) ofelectrontransport. Itis especially effective against species causing downy mildew oflettuce, spinach, onion, garlic, and cucurbits and Pythium spp. causing cavity spot ofcarrots. Italso is used for managing Alternaria spp., certain rust species, late blight (Phytophthora infestans) and early blight (Alternaria so/ani) ofpotato and fruiting vegetables, and several otherpathogens ofthe labeled crops. Fenamidone, like other Qol fungicides, exhibits translaminar movementthrough the plant leaf surface layers (Vincelli, 2012). This characteristic allows the chemical applied to one side ofthe leafto travel through the leafand bind to the cuticle on the other side, thus enhancing fungicidal protectant activity (especially inhibition ofspore germination) even with incomplete spray coverage. Qol fungicides may have some degree ofsystemic 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 ofsunflower and cotton. Fenamidone is not registered on non-agricultural sites.


### FORMULATIONS AND APPLICATION METHODS Fenamidone is formulated as an emulsifiable concentrate (EC). Itis labeledto be applied as a foliar spray, as an in-furrowtreatment, for application through chemigation, and by aerial application.

2HISTORY OF FENAMIDONE AND BEAD PRODUCTS Fenamidone was initially registered in 2002, and therefore, did not go through a reevaluation during the Registration Eligibility Decisionprocess. 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 oncarrots due to a loss ofefficacy 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 oncarrots (20%), lettuce (15%), spinach (10%), garlic (10%), onions (10%), and cucumber (5%). Fenamidone is used to a lesser extent onthe remaining crops (broccoli, cabbage, potatoes, tomatoes and watermelon).
FENAMIDONE USAGE Usage Trends: 2005-2011 Usage offenamidone, in bothtotal 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 of0.2 lbs. a.i. per acre.

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

Total Pounds Applied &Total Acres Treated

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Source: Proprietary Data, 2005-2011 

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3Table 1 shows the percentage oftotal pounds applied and total acres treated (TAT) for the five crops withthe greatest usage. Farmers may have been treating more acreage with the same overall average application rate of0.2 lbs. a.i. per acre from 2008 to 2011. 

### Table 1. 

### Cropswith Highest Use ofFenamidone- Percent ofTotalPounds Active Ingredient Applied and TotalArea Treated (TAT) in Acres, 2007-2011 Crop % ofPounds Used %TotalAcres Treated (TAT) Average% ofCrop 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 interms oftotal poundage applied and total acres treated as shown in Table 2. 

### Table 2. Comparison ofStates with Highest Use ofFenamidone- Percent ofTotal Pounds Applied and TotalArea Treated (TAT) in Acres, 2007-2011 State % ofPounds 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 ofuse in the states in Table 2 is consistent with the concentration ofuse in lettuce (California and Arizona), carrots (California), and potatoes (Idaho). 

### T bl 

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### T C op rops: A

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# .. 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: ProprietaryData, 2007-2011


### CHEMICAL AND USE CHARACTERISTICS Fenamidone and other Qol fungicides (such as azoxystrobin, pyraclostrobin, and trifloxystrobin) inhibitfungal 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

4in an amino acid change in one site ofthe 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 onthe site ofthe point mutation, a strong, moderate, or weak resistance to the fungicide canresult.
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 oncarrot (e.g., UC-Carrot, 2012). Fenamidone is among the Qoi fungicides recommended for managing early blight and late blight ofpotato (e.g., Miller and Miller, 2005; UC-Potato, 2008; UC-Potato, 2007). The Group 11 fungicides have a wide spectrum ofpathogen targets, but are considered generally athigh risk for pathogens developing resistance (FRAC, 2013). In spite ofsome 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 ofresistance concerns for all Qoi fungicides they are usually alternated or tank-mixed with fungicides ofdifferent chemical groups. In addition, the number ofapplications 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 onthe label and greenhouse ornamental crops would improve future assessments conductedby the Agency relatedto the use and benefits offenamidone. • Fenamidone appears to be used preferentially comparedto other Qoi fungicides for managing downy mildew on several crops and cavity spot in carrots. Is there efficacy information onthe use offenamidone on other crops where fenamidone may be particularly effective and used preferentially to other registered fungicides? • Current labels specify maximum amounts offenamidone to be used per acre "per growing season". Inmany 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 ofthe 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 ofenvironmental concern. • Fenamidone is registered as a seed treatment for sunflower and cotton. BEAD has no dataonthese uses. Additional informationwould be useful to assess fenamidone benefits as a seed treatment.



### 5REFERENCES BEAD. 2013. Fenamidone Screening Level Usage Analysis (SLUA). Biological and Economic Analysis Division (BEAD), Office ofPesticide 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%202013-update%20April-2013.pdf Miller, J. and Miller, T. 2005. Use offoliar 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 PestManagement Guidelines-CarrotCavity Spot. University ofCalifornia Extension. http://www.ipm.ucdavis.edu/PMG/rI02100411.html UC-Cucurbits. 2012. UC Pest Management Guidelines-Carrot Cavity Spot. University ofCalifornia Extension http://www.ipm.ucdavis.edu/PMG/rll61016II.html UC-Lettuce. 2012. UC Pest Management Guidelines-LettuceDowny Mildew. University ofCalifornia Extension. http://www.ipm.ucdavis.edu/PMG/r441100411.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 ofCalifornia Extension. http://www.ipm.ucdavis.edu/PMG/r607101211.html; UC-Potato. 2007. UC Pest Management Guidelines-Potato Early Blight. University ofCalifornia Extension. http://www.ipm.ucdavis.edu/PMG/r60710131l
.html UC-Spinach. 2012. UC Pest Management Guidelines-Spinach Downy Mildew. University ofCalifornia Extension. http://www.ipm.ucdavis.edu/PMG/r7321001Jl.html USDA, 2007. Census ofAgriculture. 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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