UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OCT 21 2013 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: MCPB and Salts Case 

(019201 (formulating use products only), 019202 (active end use products)) 

FROM: 

THRU: 

Bill Phillips, PhD, AgronomisY!Jil( 

Biological Analysis Branch ~ v 

Sepehr 

Science 

Haddad, 

Information 

Environmental 

and Analysis 

Protection 

Branch 

Specialist /f' 

vy-

..---1 ~ 

Derek Berwald, PhD, Economist ~ ()__ \}"\: j} 

Economic Analysis Branch Uj v j 

Biological and Economic Analysis Division (7503P) 

Biological 

Arnet Jones, 

Analysis 

Chief 

Bran~ 

/} . ~J {j~ . , 

Diann 

Science 

Sims, 

Information 

Chief /

and 

(U

Analysis 

/ c~ Branch 

GJ- t6 Timothy Kiely, Chief tA\ 

Economic Analysis Branch 

Biological and Economic Analysis Division (7~03P) 

TO: Khue Nguyen, Chemical Review Manager 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel date: September 18, 2013 

1 
SUMMARY 

MCPB is an herbicide that is applied postemergence to the growth of the crop and weed and 

controls annual and perennial broadleaf weeds in peas, spearmint, and peppermint. This 

herbicide is used primarily to. control perennial broadleafweeds such as Canada thistle (Cirsium 

arvense). The majority of the herbicide is used in the northern states such as New York and 

Minnesota where it is mostly used in green pea production. Based on private market usage data, 

the historic averages from 1998-2012 for usage was approximately 13,000 pounds of the acid 

annually on approximately 28,000 acres with an average rate of 0.48 pounds a.e./acre. While 

there is very little MCPB used throughout the country, it is an important herbicide for the control 

ofbroadleafweeds in broadleaf crops, specifically crops that are produced on relatively small 

acreage. 

INTRODUCTION 

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

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

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

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

information on use is available in the MCPB 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. 

USE SITES 

Agricultural Use Sites 

MCPB is registered for use on peas and mint. Tolerances exist for peas, and mint (spearmint and 

peppermint). 

Non-Agricultural Use Sites 

MCPB is not registered for non-agricultural uses. 

FORMULATIONS AND APPLICATION METHODS 

MCPB is formulated as a soluble concentrate and applied as a spray. 

HISTORY OF MCPB and BEAD PRODUCTS 

MCPB is an herbicide used for postemergence weed control and was first registered by EPA in 

1964. The Reregistration Eligibility Decision document (RED) for this chemical was published 

2 
in 2006, but BEAD has never evaluated the benefits ofMCPB. A Screening Level Usage 

Analysis (SLUA), prepared by BEAD for this chemical in 2013, provides MCPB percent crop 

treated for dry beans/peas and green peas. The percent crop treated for green peas with MCPB 

averages 15 percent, while treatment for dry beans/peas is less than one percent. The survey data 

lists dry beans/peas together; however, the registration and tolerance exist for peas only, 

therefore this implies that the percent crop treated for dry peas maybe greater than one percent. 

There is no current available usage data for mint. 

USAGE 

Agricultural Usage 

Based on private market usage data from 1998-2012, usage averaged approximately 13,000 

pounds acid equivalent (a.e.) annually on approximately 28,000 acres. The average a.e. rate over 

this time period was 0.48 pounds a.e./acre. Figure 1 presents MCPB usage in pounds a.e. and 

total area treated in acres over the 1998-2012 timeframe (Proprietary Data 1998-2012). 

Total use in pounds a.e. applied appears to be relatively steady from 1998-2012 despite a sharp 

spike in total area treated between 2007 and 2009. The spike in 2009 may be an artifact of the 

sampling procedure rather than a reflection of actual use changes. The sample sizes on dry beans 

and peas is small, and in 2009 there was a one year increase in use shown in Idaho with a small 

sample size that represented 75% of the use on those crops for that year. 

FIGURE 1. MCPB Pounds A.E. Applied and Total Area Treated in Acres (1998-2012) 

60,000 .,...---.- - - --- - ---------

...,._Pounds AE 

- Total Area Treated 

0 00 en 0 .-i N ..., "" U"l ID ,.... 00 en 0 .-i N en en 0 0 0 0 0 0 0 0 0 0 .-i .-i .-i 

en en 0 0 0 0 0 0 0 0 0 0 0 0 0 .-i .-i N N N N N N N N N N N N N 

Years 

-

Source: Proprietary Data, 1998-2012 

Table 1 shows the percent of total MCPB pounds applied for the 2003-2007 and the 2008-2012 

timeframes. 

3 
T bl 1 P a e . ercen t f T t I o oa MCPB Lb s. A ~.p)!Jle r d* 

2003-2007 2008-2012 

Average annual = 11,700 lbs a. e. Average annual= 14,000 lbs a.e. 

Crop %Lbs Crop %Lbs 

Peas, Green 91 Peas, Green 55 

Dry Beans/Peas** 9 Dry Beans/Peas** 45 

*Does not mclude use on mmt, for which data are not currently avatlable. 

**The survey data lists dry beans/peas together, but the registration and tolerance exist for peas only. 

Source: Proprietary Data, 2002-2012 

The percent of total pounds a. e. applied on green peas accounted for most use in both time 

frames, even though usage declined on green peas in the 2008-2012 timeframe when compared 

to the earlier period. Additionally, a large increase in use on dry peas (as a percent of total 

pounds a.e. applied) was seen between the two time frames (9% in the 2003-2007 timeframe to 

45% of total use in the 2008-2012 timeframe ). However, as previously mentioned, the spike in 

2009 may be the reason for this large increase but may also be an artifact of the sampling 

procedure, rather than a reflection of actual use changes. 

As shown in Table 2, New York was the state with the highest use ofMCPB in percent of total 

pounds a.e. applied in both the 2003-2007 and 2008-2012 timeframes, followed by Minnesota, 

Washington and Wisconsin in 2003-2007, and Idaho, Minnesota and Washington in 2008-2012. 

Use ofMCPB in Washington increased to 20% of total pounds a.e. applied in the latter 

timeframe, and use decreased in Minnesota between the two time periods. MCPB use increased 

in Idaho to 18% oftotal pounds applied in the 2008-2012 timeframe. 

Table 2. Comparison of States with Highest Use of MCPB- Percent of Total Lbs. Applied 

Between the 2003-2007 and 2008-2012 Timeframes 

2003-2007 2008-2012 

Average annual= 11,700 lbs a.e./yr Average annual = 14,000 lbs a.e./yr 

State %Lbs State %Lbs 

New York 64% New York 46% 

Minnesota 24% Washington 20% 

Washington 5% Idaho 18% 

Wisconsin 4% Minnesota 12% 

Other* 3% Other* 4% 

Other States m the 2003-2007 ttmeframe were Idaho, Oregon and Texas, and m the 2008-2012 ttmeframe were 

Michigan, Wisconsin and Oregon 

Source: Proprietary Data, 2003-2012 

4 
Application Rates 

T a e . bl 3 MCPBU seon T C op rops, 2008 2012 -

Crop Average Pounds Average Total Acres Avg. Use Rate Qbs 

Applied Treated* a.e./acre) 

Peas, Green 39,000 79,500 0.49 

Dry Beans/Peas 31,300 81,200 0.39 

*Total Acres Treated sums all acres treated for a crop, mcludmg those acres that receive multiple treatments. 

Source: EPA Proprietary Data, 2008-2012 

CHEMICAL AND USE CHARACTERISTICS 

MCPB is a synthetic auxin herbicide in the Weed Science Society of America herbicide group 

four. The mechanism of action of this herbicide is not well understood but the chemical is 

~hought to act much like the endogenous plant hormone auxin. Auxins are primarily responsible 

for cell plasticity, elongation and cell division. The mode of action of this herbicide is to cause 

abnormal cell growth and elongation at the growing points and plant nodes, leaf attachments, and 

internodes, the length of stem between nodes. The abnormal growth results in a distorted and 

constricted vascular system and ultimately total blockage of the vascular system. Phytotoxicity 

of MCPB comes from the translocation of the herbicide in the plant where it is oxidized to the 

herbicide MCPA which affects the herbicidal control (Worthing and Hance, 1991). 

While MCPB has been registered since 1964, to this date BEAD has been unable to find reports 

of resistant weeds. 

ROLE OF MCPB IN PEST MANAGEMENT 

This herbicide is primarily used to control the invasive noxious perennial weed Canada thistle 

following emergence of the weed. This weed is considered a noxious weed in many states and is 

required by law to be controlled. Canada thistle is a very important weed to control in any crop 

especially in broadleaf crops where there are few herbicides that can control this weed. Canada 

thistle is a very destructive invasive perennial weed that reproduces abundantly via seed as well 

as below ground reproductive structures. While there is very little MCPB used throughout the 

country it can be an important herbicide for use in peas for the control of this weed. 

DATA NEEDS 

Obtaining usage data for mint such as pounds used and acres treated, may improve future 

assessments conducted by the Agency related to the use and importance of MCPB. 

5 
REFERENCES 

BEAD, 2013. MCPB Screening Level Usage Analysis. Biological and Economic Analysis 

Division, Office of Pesticide Programs, US Environmental Protection Agency. February 15. 

Heap, I. The International Survey of Herbicide Resistant Weeds. Online. Internet. Wednesday, 

August 14th, 2013. Available www.weedscience.com 

Nickerson, C., R. Ebel, A. Borchers, and F. Carriazo. 2011. Major Uses of Land in the United 

States, 2007. USDAIERS. Economic Information Bulletin Number 89. 

Proprietary Data. 1998-2012. (pesticide usage data) 

Senseman, Sed. 2007. Herbicide Handbook Ninth Edition. Weed Science Society of America. 

810 E. lOth street. Lawrence, KS 66044-8897. U.S.A. 

US Census. 2012. Statistical Abstract of the United States 2012. Table 358 

USDA, 2006-2010. NASS Crop Reporting Districts (shape file ofCRDs). Available at: 

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

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

http://www.nass.usda.gov/Data and Statistics/County Data Files/Frequently Asked 0 

uestions/county list.txt 

USDA, 2007. Census of Agriculture. Online: 

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

USDA, 2007. Census of Agriculture. (for Land in Farms data). Available at: 

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

Worthing, CR and RJ Hance ed. 1991. The Pesticide Manual, Ninth Edition. The British Crop 

Protection Council. 49 Downing Street, Farnham, Surrey GU9 7PH UK 

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