UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

AUG 12 2013 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: Acibenzolar-S-methyl 

(061402) 

FROM: 

THRU: 

Carl Chen, Plant Pathologist 

Biological Analysis Branch 

JihadAlsadek,Economist .,rlJ A-£..~ Science Information and Analysis Branch 

Michelle Ranville, Economist 1 ll(_(XJ 

Economic Analysis Branch ~ ~ 

Biological and Economic ysis Division (7503P) 

Arnet Jones, Chief 

Biological Analysis Br 

Diann Sims, Chief ~,_,J,__,.-­ Science Information and Analysis Branch 

Timothy Kiely, Chief ....-,(1 V l.._ ~ B Au:J~~ Z0(~ Economic Analysis Branch i -, 'V"u"· f1 

Biological and Economic Analysis Division (7503P) 1trr -r.~ ~:\et--Y 

TO: Dana Friedman, Chemical Review Manager 

Risk Management and Implementation Branch 3 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel date: June 12, 2013 

INTRODUCTION 

The purpose of this document is to convey usage information and a broad overview of the pest 

management role of acibenzolar-S-methyl as it begins to undergo Registration Review. The 

anticipated audience consists of the team of EPA staff currently evaluating the registration status 

of acibenzolar-S-methyl and eventually the general public. This document builds upon the Label 

Use Information System (LUIS) reports and Screening Level Usage Analysis (SLUA) that 

1 
BEAD provides to the Registration Review team. This document is based on information and 

data available to BEAD as of May 2013. A RED was done in 2007 for this chemical. 

Acibenzolar-S-methyl belongs to the benzo-thiadiazole (BTH) chemical group of fungicides 

which controls or suppresses diseases by inducing the host plant's defense responses (FRAC, 

2013). The chemical has no direct activity on pathogens. This chemical is unique in that it is 

registered to target fungi, bacteria, and plant-parasitic nematodes. It is registered to control or 

suppress some important plant diseases such as downy mildew on lettuce, spinach, cucurbits, and 

cole crops; bacterial diseases caused by Xanthomonas spp. or Pseudomonas syringae on 

tomatoes, peppers, and cucurbits; blue mold on tobacco; and black root rot, Fusarium wilt, and 

early season plant-parasitic nematodes on cotton. 

COMMON FORMULATIONS AND APPLICATION METHODS 

Acibenzolar-S-methyl is formulated as water dispersible granules and flowable concentrate. 

Acibenzolar-S-methyl may be applied as a band treatment, broadcast, chemigation, directed 

spray, foliar treatment, seed treatment, or soil/media treatment. 

USE SITES 

Agricultural Use Sites 

Acibenzolar-S-methyl is registered on cole crops, cotton, cucurbits, fruiting vegetables, lettuce, 

onion, peppers, chili peppers, small fruits (e.g., blueberries), spinach, sunflower, tobacco and 

tomato. 

Non-agricultural Use Sites 

Acibenzolar-S-methyl is registered on commercial/industrial lawns, golf course turf, ornamental 

lawns and turf, and ornamental sod farm (turf). 

USAGE 

Agricultural Usage 

Figure 1 shows the use of acibenzolar-S-methyl in terms of annual total pounds active ingredient 

used for the period 2000-2011. This time frame shows an increase in usage from 2000-2005, and 

a decrease thereafter through 2011. During this time period (2000-2011), the annual total 

agricultural usage averaged approximately 1,000 pounds a.i. to treat approximately 48,000 acres 

for an average application rate of 0.02 lbs. a.i. per acre. The average annual application rates for 

the top crops are 0.02 lb. a.i. per acre for both spinach and lettuce, and 0.01 lb. a.i. per acre for 

tomatoes. 

2 
Fi 

2,500 

PoundsA.I. 

0 

0 

0 

N 

.-t 

0 

0 

N 

N 

0 

0 

N 

Source: Proprietary Data, 2000 -2011 

("() 

0 

0 

N 

v 

0 

0 

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L.l1 

0 

0 

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Years 

1.0 

0 

0 

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0 

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co 

0 

0 

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C'l 

0 

0 

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Figure 2 presents the agricultural usage for the more recent 2007-2011 timeframe. Usage 

averaged approximately 1,000 pounds active ingredient (a.i.) annually on 53,000 treated acres 

with an overall application rate of 0.02 lbs. a.i. per acre. During this time frame, the crops with 

the highest use in terms of percent oftotal pounds of active ingredient applied are spinach (64%), 

lettuce (23%), and tomatoes (10%). Other crops accounted for 3% ofuse. 

PoundsA.I. 

" 0 

0 

N 

co 

0 

0 

N 

Source: Proprietary Data, 2007-2011 

C'l 

0 

0 

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Years 

0 

.-t 

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3 

.-t 

.-t 

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-+-Spinach 

_..Lettuce 

....-Tomatoes 
Table 1. Acibenzolar-S-methyl Top Crops in Terms of Percent of Total Pounds Applied, 

Total Acres Treated (TAT), and Average Annual Application Rates in Lbs. a.i. per Acre 

Tomatoes 

%Total Pounds 

A.l. Applied 

Source: Proprietary Data, 2007-2011 

% Total Acres 

Treated 

16 

16 

Average 

Percent Crop 

Treated 

Average Annual 

Application Rates in 

Lbs. A.I./A 

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

applied are California (76%), Arizona (11 %), and Florida (10%). (Proprietary Data, 2007-2011). 

Agricultural Usage by Crop Reporting District 

Another measure of usage is the use intensity. In this analysis, the use intensity is expressed as 

the pounds a.i. applied per thousand acres of land in farms. This differs from the application 

rate, which is expressed as the pounds a.i. applied per treated area. The average application rate 

for the period 2007 to 2011 is 0.02lbs. a.i. per acre or 20 lbs. per 1000 treated acres. As shown 

in Figure 3, however, maximum use intensity is about 0.147lbs per 1000 acres ofland in farms. 

The areas depicted in red on the map in California are mainly for lettuce and spinach in 

particular because of the high proportion of crop acres in leafy vegetable production in CA. 

Intensity may also be linked to the high application rate for lettuce and spinach (0.02 lb. a.i./a) 

compared to the tomato application rate (0.01lb. a.i./a). It is important to note that usage data 

may not cover all states where a surveyed crop is grown. For example, use of acibenzolar-Smethyl does not appear in Colorado although records of Emergency Exemptions indicate that it 

has been requested for use there on onions. Appendix A contains additional details on the 

sources of data used in Figure 3. 

4 
Figure 3. Acibenzolar-S-methyl Use Intensity by Crop Reporting District (2007-2011) 

Average Pounds Per 

1,000 Acres of Farmland 

- <0.010 

0.010- 0.029 

0.030- 0.053 

0.054-0.147 

Sources: Proprietary Data, 2007-2011; USDA, 2007 

BIOLOGICAL ASPECTS RELEVANT TO ACIBENZOLAR-S-METHYL 

Acibenzolar-S-methyl is unique in control and suppression of disease in foliar application and 

seed treatment. For best results it must be applied preventively, before infection occurs and 

before symptom development (UC IPM, 2012). The chemical has no direct activity on 

pathogens. It exhibits a unique mode of action to induce systemic acquired resistance (SAR) 

(Monda! et al., 2005). Resistance is not known for acibenzolar-S-methyl (FRAC, 2013). 

Resistance management practices described on the label include rotating and/or tank mixing with 

pesticides with different modes of action since plant pathogens may develop tolerance to host 

plant resistance. 

THE ROLE OF ACIBENZOLAR-S-METHYL IN PEST MANAGEMENT 

The role of acibenzolar-S-methyl in pest management is unique. It is a control option in a pest 

and resistance management program involving diseases and alternatives that have a high risk of 

developing resistance. It is a candidate suitable for an integrated pest management (IPM) 

program because it is related to host plant resistance and cultural practices. It is used to control 

5 
\ 

bacterial diseases as an alternative to antibiotics and EBDC fungicides such as mancozeb. It is 

employed not only as a foliar application but also a seed treatment. Finally, acibenzolar-Smethyl is unique in that it can be used to control nematode pests. 

Acibenzolar-S-methyl has also been used to control iris yellow spot virus (IYSV) under 

emergency exemptions through Section 18 of the Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA). Emergency exemptions for the use of acibenzolar-S-methyl on 

onions in the state of Colorado were granted for three consecutive years from 2007 to 2009. 

BEAD conducted two reviews for this emergency exemption request (Y ourman and Rim, 2004; 

Y ourman and Faulkner, 2009), both of which found the situation in Colorado onions to be urgent 

and non-routine and likely to cause significant economic loss. The use was approved later for a 

FIFRA Section 3 registration. 

Downy mildew is the most widespread and destructive spinach disease in California. 

Acibenzolar-S-methyl has been recommended for use against downy mildew in 10 counties, 

many of them are in the areas depicted in red on the map (Figure 3; UC IPM, 2012). White rust, 

a major foliar fungal disease of spinach in the Southeastern U.S., was controlled by a 

combination of acibenzolar-S-methyl and strobilurin without causing leaf chlorosis (Leskovar 

and Kolenda, 2002). In 2011, acibenzolar-S-methyl was the top fungicide in acreage treated, 

suggesting that it played a significant role in spinach disease management (Proprietary Data). 

Acibenzolar-S-methyl may also have potential for controlling pests that are not listed on the 

label. Its unique mode of action that mimics SAR response in many plant species can be 

considered as an asset for control of some diseases. A FIFRA Section 2( ee) recommendation for 

Daconil ActionTM, a combination product of active ingredients acibenzolar-S-methyl and 

chlorothalonil, has been issued for suppression of Pythium blight and bacterial wilt on turfgrass 

in California, Florida, New York, Texas, and other states (CDMS, 2013). 

DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON ACIBENZOLAR-SMETHYL 

Additional information, in terms of pounds a.i. applied, average application rate, regional 

application, time of application, and number of applications per year on non-agricultural sites 

(e.g., ornamental turf) would improve future assessments of the importance of acibenzolar-Smethyl for pest management and may be useful as part of the registration review of this 

pesticide. 

REFERENCES 

CDMS. 2013. Crop Data Management Systems. http://premier.cdms.net/webapls. Accessed May 

20 13.EPA. Acibenzolar-S-methyl. Online: 

http://iaspub.epa.gov/apex/pesticides/f?p=CHEMICALSEARCH:3:0::NO:l,3,31,7,12,25:P3 XCHE 

MICAL ID:79 

FRAC. 2013. Fungicide Resistance Action Committee. http://www.frac.info/frac/index.htm Accessed 

May 2013. 

6 
Leskovar Dl, Kolenda K. 2002. Strobilurin + acibenzolar-S-methyl controls white rust without inducing 

leaf chlorosis in spinach. Annals of Applied Biology, 140: 171-175. 

Mondal, A. H., D. B. Nehl, and S. J. Allen. 2005. Acibenzolar-S-methyl induces systemic resistance in 

cotton against black root rot caused by Thielaviopsis basico/a. Australian Plant Pathology 34(4): 

499-507. http:/ /link.springer.com/article/1 0.1071 %2F AP05089# Accessed May 20 13Proprietary 

Data, 2000-2011 

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

http://www.ipm.ucdavis.edu/PMG/r73210011l.html Accessed June 2013. 

USDA NASS. Chemical Use Surveys, 2006 and 2009. 

http://www.nass.usda.gov/Surveys/Guide to NASS Surveys/Chemical Use/#description 

USDA, 2006-2010. NASS Crop Reporting Districts. Online: 

http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass. 

USDA, 2007. Census of Agriculture. Online: 

http://www .agcensus. usda.gov/Publications/2007 /index.asp. 

Yourman, L. and E. Rim. 2004. Request for Emergency Exemption Use of Acibenzolar-S-methyl 

(Actigard®) to Manage Iris Yellow Spot Virus of Onions in Colorado (04-C0-10) [DP # 061402] 

Yourman, L. and J. Faulkner. 2009. Request for an Emergency Exemption for Acibenzolar-S-methyl 

(Actigard") to Manage Iris Yellow Spot Virus of Onions in Colorado (09-C0-02; DP362704) 

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APPENDIX A- Details of Agricultural Pesticide Usage Map 

The maps of agricultural pesticide usage at the Crop Reporting District (CRD) level are prepared by BEAD 

for use in the Environmental Fate and Effects Division (EFED) documents. These maps are used to help 

visualize where the pesticide being considered is most likely to be used and can be helpful in scenario 

selection and placing the exposure assessment in context. CRDs are boundaries created by USDA NASS 

which are aggregates of counties. Pesticide usage is displayed as average pounds (for the years 2007-2011) 

per 1,000 acres of farmland in a CRD to normalize for the variation in farmland between CRDs. Farmland 

acreage was obtained from USDA (2007). Farmland or "land in farms" is defmed as follows: 

The acreage designated as "land in farms" consists primarily of agricultural land 

used for crops, pasture, or grazing. It also includes woodland and wasteland not 

actually under cultivation or used for pasture or grazing, provided it was part of 

the farm operator's total operation. Large acreages of woodland or wasteland 

held for nonagricultural purposes were deleted from individual reports during 

the edit process. Land in farms includes CRP, WRP, FWP, and CREP acres. 1 

Land in farms is an operating unit concept and includes land owned and 

operated as well as land rented from others. Land used rent free was reported as 

land rented from others. All grazing land, except land used under government 

permits on a per-head basis, was included as "land in farms" provided it was 

part of a farm or ranch. Land under the exclusive use of a grazing association 

was reported by the grazing association and included as land in farms. All land 

in American Indian reservations used for growing crops, grazing livestock, or 

the potential of grazing livestock was included as land in farms. Land in 

reservations not reported by reservation, individual American Indians or nonNative Americans was reported in the name of the cooperative group that used 

the land. In many instances, an entire American Indian reservation was reported 

as one farm (USDA, 2007). 

Usage is based on private market surveys of pesticide use in agriculture (Proprietary Data, 2007-2011). The 

survey data are limited to the states that represent the top 80-90% of acreage for the individual crops; 

therefore, use may be occurring in regions outside the scope of the survey. CRDs showing no usage of 

pesticides may be due to either the lack of pesticide use in the region or non-participation in the agricultural 

surveys. In addition, across the years, there may be variations in the specific crops included in the CRD 

survey. This may result in a lower annual average for the CRD. 

This map displays ratio data (i.e., average pounds per 1,000 acres of farmland) summarized at a very highlevel. Readers are strongly cautioned against trying to over interpret the map without examination of the 

underlying data. The underlying data may explain some of the many reasons that a Crop Reporting District 

may have a high value for a particular active ingredient such as significant acreage (compared with the CRD 

as a whole) of a crop or crops with a high application rate and frequency of application. 

The reader should pay particular attention to the figure legends and realize that a map prepared for a 

particular chemical is not directly comparable to a map prepared for a different chemical. Scale and units of 

measurement do matter and may be different between maps. 

1 CRP: Conservation Reserve Program; WRP: Wetland Reserve Program; FWP: Farmable Wetlands Program; 

CREP: Conservation Reserve Enhancement Program 

8