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builds upon the data already provided in the “Usage and Label Use Data Packages” that are also 

provided to Registration Review teams by BEAD. The document is based on information and 

data available to BEAD as of October 4, 2012. 

EPTC is in the Weed Science Society mechanism of action group 8, a thiocarbamate herbicide 

(WSSA, 2011). Thiocarbamate herbicides inhibit seedling growth. EPTC is used as a preemergence and early post-emergence herbicide to control growth of geminating annual weeds, 

including broadleaves, grasses, and sedges. EPTC does not control established weeds. 

HISTORY OF BEAD ASSESSMENTS FOR EPTC 

BEAD has not assessed the benefits of EPTC in the past. 

COMMON FORMULATIONS AND APPLICATION METHODS 

EPTC is formulated as granular or emulsifiable concentrate and it is applied as a banded 

treatment, broadcast, chemigation, ground treatment, spot treatment, and as a strip spray. 

USE SITES 

 

Agricultural Uses

EPTC is labeled for use on alfalfa, beans (snap, bush, pole, string), sweet corn, sugar beets, 

sunflowers, tomatoes, almonds, cotton, broccoli, fallow, walnuts, lima beans, carrots, and citrus. 

Non-Agricultural Uses 

EPTC is labeled for use on ornamental trees, herbaceous plants, and woody shrubs and vines. 

AGRICULTURAL USAGE 

Based on private market pesticide usage data, EPTC’s annual (2006 – 2011) agricultural usage 

averaged 1.6 million pounds of active ingredient treating an average of 592 thousand acres, for 

an average application rate of 2.7 pounds per acre. 

From 2006-2011, potatoes (47%), dry beans/peas (32%), and beans (11%) accounted for the 

largest percentages of usage in terms of total pounds of active ingredient applied. For the same 

period of time (2006-2011), potatoes (40%), dry beans (38%), and beans (11%) accounted for 

the largest percentages of total area treated (TAT). Relative proportions indicate that the 

application rate for potatoes is somewhat higher than the overall average rate while that for dry 

beans and peas is somewhat lower. 

Table 1 below shows the top states in terms of pounds applied and TAT from 2006-2011. 

 
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Table 1. EPTC’s Top States in Terms of Average Pounds Applied and TAT (2006-2011). 

State Pounds Applied Total Area Treated (TAT) 

Idaho 29% 26% 

Washington 15% 14% 

Michigan 10% 14% 

(Proprietary data, 2006-2011). 

USE TRENDS 

Figure 1 depicts usage trends, in terms of pounds applied, for EPTC’s largest agricultural market. 

Overall, the chart below shows that the use of EPTC decreased for all top crops from 1998 

through 2011. In Figure 1, “Other” refers to (in order of high to low average pounds applied): 

alfalfa, beans (snap, bush, pole, string), sweet corn, sugar beets, sunflowers, tomatoes, almonds, 

cotton, broccoli, fallow, walnuts, lima beans, and carrots. 

Figure 1. Pounds of EPTC Applied on Major Crops (1998-2011).

Source: (Proprietary data, 1998-2011) 

 Figure 2 depicts the total pounds of EPTC used from 1998 to 2011. In it is evident that this 

chemical’s usage has been in decline. (Proprietary data, 1998-2011). Although slowing, this 

decline has continued through the 2006 to 2011 period analyzed above. 

0

5,000,000

Corn

Potatoes

Dry Beans/Peas

Other
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Figure 2. Total Pounds of EPTC Applied from 1998-2011.

Source: (Proprietary data, 1998-2011) 

ADDITIONAL USAGE INFORMATION 

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

the pounds a.i. applied per acre of land in farms. This differs from the application rate, which is 

expressed as the pounds a.i. applied per treated acre. Note that the average application rate is 

about 2.7 pounds per acre, or 2,700 pounds per 1,000 acres. The map shows the highest intensity 

of use is between 56 and 95 pounds per 1,000 acres. Figure 3 spatially represents EPTC's use 

intensity in the US. In Figure 3, concentrations of use can be seen. These correspond to potato 

production areas in the Central Washington, Southern Idaho, the San Luis Valley of Colorado, 

Central Wisconsin and Western Michigan. The use shown around the Saginaw Bay of Michigan 

is probably a result of use on dry edible beans. There is also high concentration of use shown in 

the Willamette Valley and Coastal Oregon, although these are not primary production areas for 

potatoes or dry beans; in this area the use seems to be on fresh beans. 

‐

10,000,000

Total Pounds AI Applied

Year
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Figure 3. EPTC Usage by Crop Reporting District (2007 – 2011). 

This is a map of agricultural pesticide usage at the Crop Reporting District (CRD) level prepared by BEAD 

for use in the Environmental Fate and Effects Division 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 defined by USDA (2007) 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 acres1

. 

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 

 

1

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

 CREP: Conservation Reserve Enhancement Program 
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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. 

 

NON-AGRICULTURAL USAGE 

Available non-agricultural databases were consulted yet no usage was found. 

BIOLOGICAL ASPECTS RELEVANT TO EPTC 

The Weed Science Society of America documents weed resistance to Group 8/thiocarbamate 

herbicides but does not list EPTC as the specific herbicide with the resistance issue (WSSA, 

2012). However, the Montana State University Extension lists a biotype of wild oat as a weed 

resistant to EPTC in Montana (MSU Extension, 2011). Pest management guidelines indicate 

that repeated annual use of EPTC may result in weed resistance or decrease herbicide 

performance (UC IPM, 2011). This may be the result of increased levels of soil microbes that 

degrade EPTC (KSRE, 2010; UC IPM, 2011). Rotations with herbicides of different chemistries 

are an option for preventing resistance as recommended by pest management guideline (UC 

IPM, 2011). Overall, herbicide resistance does not appear to be a widespread problem with 

EPTC (WSSA, 2012). 

INFORMATION THAT MAY BE USEFUL FOR BEAD’S FUTURE WORK ON EPTC 

Obtaining additional information on non-agricultural usage, such as pounds active ingredient 

applied per year by site, would improve future BEAD assessments of the importance of EPTC 

and may be required as part of the registration review of this pesticide. 

 
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REFERENCES 

KSRE, 2010. Herbicide mode of action. Kansas State University research and extension: C-715. 

Online: http://www.ksre.ksu.edu/library/crpsl2/c715.pdf. Verified: October 11, 2012. 

MSU Extension, 2011. Preventing and managing herbicide-resistant weeds in Montana. 

Montana State University Extension. MontGuide: MT200506AG. Online: 

http://msuextension.org/publications/AgandNaturalResources/MT200506AG.pdf. Verified: 

October 10, 2012. 

Proprietary data, 1998-2011. 

Proprietary Data, 2007-2011. 

UC IPM, 2011. UC IPM Pest Management Guidelines: Corn – special weed problems. UC 

ANR Publicaiton 3443. Online: http://www.ipm.ucdavis.edu/PMG/r113700211.html. 

Verified: October 3, 2012. 

USDA, 2007. Census of Agriculture. Online: 

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

http://www.agcensus.usda.gov/Publications/2007/Full_Report/Volume_1,_Chapter_1_US/usa

ppxb.pdf. Verified: October 10, 2012. 

WSSA, 2012. Thiocarbamates and other (N/8) resistant weeds. Online: 

http://www.weedscience.org/Summary/UspeciesMOA.asp?lstMOAID=22&FmHRACGroup=Go

Verified: October 3, 2012. 

WSSA, 2011. WSSA classification of herbicide mechanism of action (revised June 10, 2011). 

Online: http://www.wssa.net/Weeds/Resistance/WSSA-Mechanism-of-Action.pdf and 

http://www.wssa.net/Weeds/Resistance/index.htm. Verified: October 3, 2012.