UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

DEC 2 0 2013 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: Thiabendazole Case 

(060101, 060102) 

FROM: Carl Chen, Biologist /(,U) IV!Ji Mjj;; FiJI( M ~ Biological Analysis Branch -

Sepehr Haddad, Environmental Protection Specialist ~ \1)- \}II_ / ~ Science Information and Analysis Branch \J 0 v \J 

Andrew Lee, Economist a.. L {! k 

Economic Analysis Branch f . Biological and Economic Analysis Division (7503P) 

THRU: Arnet Jones, Chief tj/,L {j (/A ~/4Ji:. flu( /kne&- ,JMM 

Biological Analysis Branch 1 vj ' --

Diann Sims, Chief hr !]3- W\.. . Science Information and Analysis Branch ~ 

Timothy Kiely, Chief Q} ~ Economic Analysis Branch 

Biological and Economic Analysis Div' 'on (7503P) 

TO: Ricardo Jones, Chemical Review Manager 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel date: September 4, 2013 

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SUMMARY 

Thiabendazole is a fungicide first registered in the U.S. in 1969. It is used to control some 

important soil-borne and postharvest diseases on commodities such as citrus, potatoes, 

mushrooms, soybeans, and wheat. The agricultural uses ofthiabendazole include seed 

treatments, and post-harvest uses. There used to be foliar uses, but these uses were associated 

with Special Local Need 24 (c) registrations and have all been canceled. The majority of usage 

in pounds active ingredient (a.i); however, is from post-harvest use. Thiabendazole has been 

reported to control green mold and blue mold on postharvest citrus fruits. The only nationally 

publicly available data are proprietary market information for seed treatment on spring wheat, 

soybeans and potatoes, and limited data for post-harvest potato use are available from the USDA. 

Even though it is not nationai data, the California Department of Pesticide Regulation (CDPR) 

also provides usage information for citrus and mushrooms which are the major crops in terms of 

pounds a.i. used. California is the primary producer of fresh citrus in the U.S., and is second 

only to Pennsylvania in mushroom production in the U.S. In 2011, approximately 1.6 million 

tons of oranges were treated with thiabendazole in California. It must be noted that available 

non-agricultural usage data for thiabendazole are limited and dated (most recent data available is 

from 2005); however, the data did indicate relatively high usage as a biocide. 

The thiabendazole case for registration review includes another active ingredient, thiabendazole 

hypophosphite. It is a furlgicide registered as a tree injection as a preventative treatment for 

Dutch elm disease and anthracnose. In 2011, thiabendazole hypophosphite was used for 

landscape maintenance in California. 

INTRODUCTION 

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

overview of the pest management roles and quantitative usage information for thiabendazole 

(TBZ). The BCP includes summaries of previous BEAD products and available public and/or 

private use and usage data for thiabendazole to describe the role of this chemical in pest 

management. Additional information on use is available in the thiabendazole PRD Label Data 

Report. This registration review case for thiabendazole and salts also includes another active 

ingredient, thiabendazole hypophosphite (PC Code: 060102). 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 for this pesticide. · 

USE SITES 

THIABENDAZOLE: 

Agricultural Use Sites 

Thiabendazole registered agricultural use sites includes apples (postharvest), banana 

(postharvest), barley, beans (seed treatment), carrots (postharvest), citrus fruits (postharvest), 

clover (seed treatment), com (field, sweet and pop) (seed treatment), lentils, mangos 

(postharvest), mushrooms (soil, postharvest, and spawn treatment), ornamental bulbs and corms 

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(dip treatment) papayas (postharvest), pears (postharvest), peas (seed treatment), plantain 

(postharvest), potatoes (seed treatment and postharvest), sweet potatoes (dip and seed treatment 

and postharvest), soybeans (seed treatment), and wheat (seed treatment). Even though there are 

no U.S. registrations for avocados, cantaloupes, and strawberries, tolerances have been 

established for residues of thiabendazole on these crops. Tolerances for beets expired on 

12/25/2010. 

Non-agricultural Use Sites 

Thiabendazole registered non-agricultural use sites includes adhesives, air filter materials, 

awnings, canvas products, boat covers, carpets, caulking compounds, coatings (aqueous, nonaqueous, and plastic), foam rubber, grouts, paints, paper and paper products, sealants, tarpaulins, 

tents, textiles and textile finishes, vinyl wall paper pastes, and wallboard joint compounds. 

THIABENDAZOLE HYPOPHOSPHITE: 

Thiabendazole hypophosphite is registered as a tree injection for elm, oak and sycamore. In 

addition it is registered for aqditive treatment to industrial adhesives, carpets, paints, and textiles. 

FORMULATIONS 

Thiabendazole is formulated as a ready-to-use, dusts, flowable concentrates, emulsifiable 

concentrates, wettable powders, granules, and water dispersible granules. 

Thiabendazole hypophosphite is formulated as a soluble concentrate/liquid. 

APPLICATION METHODS 

THIABENDAZOLE: 

Thiabendazole can be applied by dipping, spraying, or application during the waxing procedure 

for fruits and vegetables. Seed treatments are applied with a ready-mix or slurry-mix. A readyto-use formulation is added t? paints, carpets, textiles and adhesives. 

Postharvest applications are made to the following: apples, bananas, carrots, citrus, mangos, 

mushrooms, papayas, pears, plantains, potatoes, and sweet potatoes. 

Seed treatment applications are made to beans, clover, com, lentils, peas, potatoes, soybeans, 

sweet potatoes, and wheat. 

THIABENDAZOLE HYPOPHOSPHITE: 

Thiabendazole hypophosphite is applied as an additive treatment and tree injection treatment. 

HISTORY OF THIABENDAZOLE CASE AND BEAD PRODUCTS 

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Thiabendazole is a fungicide first registered in the U.S. in 1969. The Reregistration Eligibility 

Decision document (RED) was published in 2002. A Screening Level Usage Analysis (SLUA) 

was prepared by BEAD for this chemical in 2013 which provides percent crop treated for 

potatoes, soybeans, and wheat. For these three crops, the percent crop treated was for seed 

treatment with thiabendazole. and was quite low (less than 2.5%). 

Recently, section 18 requests for use on mushrooms by California, Delaware, Maryland, and 

Pennsylvania have been approved by OPP, which suggests value of thiabendazole for this use. 

USAGE 

THIABENDAZOLE: 

Agricultural Usage 

The agricultural uses of thiabendazole include seed treatments and post-harvest uses. The 

majority of usage in pounds active ingredient (a.i); however, is from post-harvest use. 

The only national publicly available information on post-harvest use is from the USDA National 

Agricultural Statistics Servic~ (NASS) which provides data for the 2005-2006 marketing year 

showing that approximately 300 lbs. a.i. of thiabendazole was used to treat less than 1 percent 

(0.6 percent) of postharvest potatoes before entering storage. (USDA, 2007). 

Even though it is not national data, the California Department of Pesticide Regulation (CDPR) 

also provides information for use on citrus and mushrooms which are the major crops in terms of 

pounds a.i. used. California is the primary producer of fresh citrus in the U.S., and is second 

only to Pennsylvania in mushroom production in the U.S. Data are available for the years 2007-

2011 from CDPR as shown in Table 1, but the data does not differentiate between the different 

application methods for mushrooms (i.e., soil, postharvest, or spawn treatment). 

Table 1. California Crops with Highest Use of Thiabendazole- Total Lbs. Applied (2007-

2011) 

Crop 2007 2008 2009 2010 2011 

Citrus 10,300 16,000 9,000 9,300 24,800 

Mushrooms 5738 4,670 3,240 5,610 6,240 

Source: California Department of Pesticide Regulation 2007-2011 

Seed Treatment 

Based on private market usage data from 2009-2011 (the only years for which usage data has 

been reported since the provider of proprietary data started collecting data on seed treatments for 

soybeans beginning in 2006, and for spring wheat and potatoes in 2009), seed treatment usage 

averaged approximately 65 pounds active ingredient (a.i.) annually on approximately 4400 acres 

treated. (Note: The acreage information presented in this BCP is an estimate according to the 

proprietary data provider since farmers often do not know if they planted a seed that has been 

treated, so the data provider estimates usage based on seed brand/seed trait that is planted). The 

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average a.i. rate for seed treatment over the 2009-2011 time period was 0.015 pounds a.i./acre. 

The major agricultural seed treatment use of thiabendazole between 2009-2011 was on spring 

wheat in Idaho, followed by use on soybeans in Illinois and use on potatoes in Wisconsin 

(Proprietary Data, 2009-2011). 

Non-Agricultural Usage 

Available non-agricultural usage data for thiabendazole are limited and dated. USDA's NASS 

Nursery and Floriculture Summary for 2004 shows 1,300 lbs used with a rate of 2.18 lbs. a.i./ A 

while the 2006 summary shows 4,000 lbs used with a rate of approximately 1.67 lbs. a.i./ A. 

Other reported non-agricultural data is from Kline & Co. for the years 2004 for landscaping at 

approximately 100 lbs a.i., and in 2006 for landscaping at approximately 3,000 lbs. a.i. and for 

golf courses at approximately 9600 lbs. a.i. (Kline & Company, 2004, 2006). According to 

Kline, thiabendazole is also used as a biocide for adhesives and sealants, with approximately 

355,000 lbs used in 2005. 

THIABENDAZOLE HYPOPHOSPHITE: 

There is very limited usage data for thiabendazole hypophosphite. The only data available 

indicates less than 100 pounqs of thiabendazole hypophosphite was used in California for 

landscape maintenance in 2011 (PUR, 2011). 

CHEMICAL AND USE CHARACTERISTICS 

THIABENDAZOLE: 

Thiabendazole is a systemic fungicide. It has been registered to control some important plant 

diseases including seed-borne and early season seedling pod and stem blight on soybean and 

common bunt (stinking smut) and Fusarium scab on wheat. It is registered to control postharvest fungal diseases such as Fusarium tuber rot on potatoes and blue mold (Penicillium 

digitatum), green mold (P. italicum) and stem end rot (Diplodia natalensis) on citrus fruit. It 

currently also has other registered uses such as controlling Fusarium basal rot and Penicillium 

blue mold on ornamental bulbs and corms, and dry bubble, wet bubble, cobweb, and green mold 

on mushrooms. 

Resistance is a concern in the use of thiabendazole. The chemical belongs to the group of methyl 

benzimidazole carbamates (MBC) classified by the Fungicide Resistance Action Committee 

(FRAC) and coded as FRAC group 1 with a high risk of resistance development (FRAC, 2013). 

Resistance to MBC fungicides is common in many fungal species. If treatment is not effective 

following use of thiabendazole, the label instructs a prompt use of other suitable nonbenzimidazole fungicides. Other labeled disease and resistance management considerations 

include one application only, associated with seed treatment and postharvest treatment. 

THIABENDAZOLE HYPOPHOSPHITE: 

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Thiabendazole hypophosphite is also a systemic fungicide. It is injected in tree trucks as a 

preventative treatment. The highest label dosage of Arbortect 20S® can be successfully used on 

a 2-3 year rotation to protect high value elms from Dutch elm disease for 15 years (Haugen and 

Stennes, 1999). Thiabendazole hypophosphite is currently registered to control Dutch elm 

disease and sycamore/oak anthracnose. 

ROLE OF THIABENDAZOLE AND THIABENDAZOLE HYPOPHOSPHITE IN PEST 

MANAGEMENT 

THIABENDAZOLE: 

The largest and most important use of thiabendazole is on citrus. Approximately 6. 7 billion 

pounds of citrus fruits were treated with thiabendazole in 2011 in California (PUR, 2011 ). The 

other most significant use of thiabendazole is non-agricultural as a biocide with approximately 

355,000 pounds of active ingredient used in 2005 (Kline & Company, 2005). 

Thiabendazole has played a significant role in postharvest disease control of valuable citrus 

commodities such as oranges and lemons. It has been recommended as a direct application to 

fruit to control green and blue mold under postharvest conditions (California Citrus Profile, 

2003). In 2011, thiabendazole was used to treat citrus fruits including approximately 1.6 million 

tons of orange in California (PUR, 2011 ). The primary end-product of citrus grown in California 

is the fresh-market, 82% for oranges compared to 5% in Florida (California Citrus Profile, 2003). 

California produces 80% of the United States lemons, approximately 700,000 tons in 2002 

(California Citrus Profile, 2003), and thiabendazole was used on approximately 680,000 tons of 

lemon fruit in 2011 (PUR, 2011). 

Thiabendazole has played a role in control of potato postharvest diseases. It is recommended for 

use as a postharvest treatment to control Fusarium tuber rot (Wisconsin Potato Profile, 2000). In 

the 2005-06 marketing year, thiabendazole and fludioxonil were two main fungicides listed in 

the report treating 0.6% and 0.1% of postharvest potatoes in the United States, respectively 

(USDA, 2007). 

California is second only to Pennsylvania in mushroom production and produces 17% of the 

mushrooms grown in the United States on 22.8 million square feet ofbeds in 1997 (California 

Mushroom Profile, 1999). In the 2011-12 marketing year, California mushroom area in terms of 

total fillings was approximately 20.5 million square feet (USDA, 2013). Thiabendazole was 

used to treat approximately 21.1 million square feet in 2011 (PUR, 2011) and, therefore, has 

played a significant role for control of mushroom diseases in California. 

Fungicide treatment of wheat seed is a very important practice to prevent seed borne diseases 

causing economic loss (Idaho Wheat Profile, 2000), and thiabendazole was used for seed 

treatment in Idaho (Proprietary Data, 201 0). Pesticide treatment of soybean seed is a widely 

used pest management practice and thiabendazole was used for soybean seed treatment in Illinois 

(Proprietary Data, 2009). Although acreage treated is low, thiabendazole remains a fungicide 

alternative in seed treatment of certain crops in certain regions. 

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Thiabendazole has also been ·used under emergency exemptions through Section 18 of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) in several states. It was needed to 

control blackleg on Brussels sprout, cabbage, and cauliflower in California and Washington and 

Aschochyta blight on lentil in Idaho, Oregon, Montan~, North Dakota, and Washington. 

THIABENDAZOLE HYPOPHOSPHITE: 

Thiabendazole hypophosphite is registered for disease prevention of trees such as elms, 

sycamores, and oaks. The label recommends that thiabendazole hypophosphite be administered 

by trained arborists or others trained in injection techniques and in the identification of diseases 

to provide protection up to three years before reapplication is needed. It has been reported that 

thiabendazole hypophosphite was used for landscape maintenance in California (PUR, 2011 ). 

DATA NEEDS 

The Agency currently does not have important information on thiabendazole related to certain 

uses. Obtaining the following information may improve future assessments conducted by the 

Agency related to the use and importance of thiabendazole. 

Post-harvest agricultural use in terms of pounds a.i. and application rates for the crops 

mentioned in the BCP. 

Non-agricultural usage data on the sites mentioned in this BCP such as: adhesives, air 

filter materials, awnings, canvas products, boat covers, carpets, caulking compounds, 

coatings (aqueous, non-aqueous, and plastic), foam rubber, grouts, paints, paper and 

paper products, sealants, tarpaulins, tents, textiles and textile finishes, vinyl wall paper 

pastes, and wallboard joint compounds. 

Usage data for thiabendazole hypophosphite. 

REFERENCES 

Page 7 of8 
BEAD, 2013. Thiabendazole Screening Level Usage Analysis. Biological and Economic 

Analysis Division, Office of Pesticide Programs, US Environmental Protection Agency. 

February 22. 

California Citrus Profile. 2003. Crop Profile - Citrus in California. California Citrus Quality 

Council; Citrus Research Board. http://www.calcitrusquality.org/cropprofile/e6adefdc-0694-

44e 1-95b2-df5c6314eeed.pdf. 

California Mushroom Profile,. 1999. Crop Profile for Mushrooms in California. 

http://www.ipmcenters.org/cropprofiles/docs/camushrooms.pdf accessed August 2013. 

California Department of Pesticide Regulation, Annual Statewide Pesticide Use Report. 2007-

2011. 

FIFRA. 2008. Federal Insecticide, Fungicide, and Rodenticide Act [As Amended Through P.L. 

110-246, Effective May 22, 2008]. http://www.epa.gov/opprd001/registrationmanual/FIFRA.pdf 

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

accessed July 2013.Idaho Wheat Profile, 2000. 

http:/ /www.ipmcenters.org/ cropprofiles/ docs/IDwheat. pdf accessed July 2013. 

Haugen L, Stennes M. 1999. Fungicide injection to control Dutch elm disease: Understanding 

the options. Plant Diagnosticians Quarterly 20 (2):29-38. 

Idaho Wheat Profile, 2000. http://www.ipmcenters.org/cropprofiles/docs/IDwheat.pdf accessed 

July 2013. 

Kline & Co. 2004-2006. 

Proprietary Data. 2009-2011. (pesticide usage data) 

PUR, 2011. Summary of Pesticide Use Report Data- 2011. California Environmental Protection 

Agency Department of Pesticide Regulation. P.O. Box 4015. Sacramento, CA 95812-4015. 

USDA NASS, Nursery and Floriculture Summary 2004,2007. 

USDA, 2007. Potato Postharvest Chemical Usage in 2005-06 Marketing Year. 

http://www .nass. usda.gov /Statistics_ by_ State/Idaho/Publications/Special_ Reports/pdf/Idaho%20 

Potatoes%20Chem%20Use.pdf accessed July 2013. 

USDA, 2013. Mushrooms. National Agricultural Statistics Service. Agricultural Statistics Board. 

USDA. http:/ /usdaO 1.library .cornell.edu/usda/ current/Mush/Mush-08-20-2013. pdf accessed 

August 2013. 

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