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 enduse products)) FROM:

THRU: Bill Phillips, PhD, AgronomisY!Jil( Biological Analysis Branch

### ~v SepehrHaddad, Environmental Protection Specialist 

# /f'..---**~** Science Information and Analysis Branch 

## vy- 1 Derek Berwald, PhD, Economist

# ~ ()__ \}"\: 

# j} Economic Analysis Branch 

## Uj v

# j Biological and Economic Analysis Division (7503P) Arnet Jones, Chief /}
.

# ~J**~** Biological Analysis

# Bran**~**

# {j
. , Diann Sims, Chief 

## /(U /

# c~ Science Information and Analysis Branch 

# GJ- 

# t6 Timothy Kiely, Chief 

# tA\ Economic Analysis Branch Biological and Economic Analysis Division**(7~03P)** TO: Khue Nguyen, Chemical ReviewManager 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 ofthe crop and weed and controls annual andperennial broadleafweeds in peas, spearmint, andpeppermint. This herbicide is used primarily to
. control perennial broadleafweeds such as Canadathistle (Cirsium arvense). The majority ofthe 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 ofthe acid annually on approximately 28,000 acres with an average rate of0.48 pounds a.e./acre. While there is very little MCPB used throughout the country, it is an important herbicide for the control ofbroadleafweeds in broadleafcrops, specifically crops that are produced onrelatively small acreage.


### INTRODUCTION The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an overview ofthe pest management roles and quantitative usage information for MCPB. The BCP includes summaries ofprevious BEAD products and available public and/orprivate use and usage data for MCPB to describe the role ofthis chemical inpest management. Additional information on use is available inthe 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 Reviewprocess ofthis pesticide.


### USE SITES Agricultural Use Sites MCPB is registered for use onpeas 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 

### 2in 2006, but BEAD has never evaluated the benefits ofMCPB. A Screening Level Usage Analysis (SLUA), prepared by BEAD for this chemical 

### in2013, provides MCPB percent crop treated for dry beans/peas and greenpeas. 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 onprivate 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 inpounds 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 

### intotal area treated between 2007 and 2009. The spike 

### in2009 may be an artifact ofthe sampling procedure rather than a reflection ofactual use changes. The sample sizes on dry beans and peas is small, and in 2009 there was a one year increase inuse shown in Idaho with a small sample size thatrepresented 75% ofthe use onthose crops for that year. 

### FIGURE 1. 

### MCPB Pounds A.E. Applied and TotalArea Treated in Acres (1998-2012)

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

...,._PoundsAE

- 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 oftotal MCPB pounds applied for the 2003-2007 and the 2008-2012 timeframes.


### 3T 

### bl 1 P a e 

# . t f T t IMCPB Lb A 

## r d* ercen o oa s.**~.p)!Jle**



### 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 oftotal pounds a.e. applied on green peas accounted for mostuse inbothtime frames, eventhough usage declined on green peas inthe 2008-2012 timeframe when compared to the earlierperiod. Additionally, a large increase 

### inuse on dry peas (as a percent oftotal pounds a.e. applied) was seen between the two time frames (9% inthe 2003-2007 timeframe to 45% oftotal use inthe 2008-2012 timeframe). However, as previously mentioned, the spike in 2009 may bethe reason for this large increase but may also be an artifact ofthe sampling procedure, ratherthan a reflection ofactual use changes. As shown in Table 2, New York was the state withthe highest use ofMCPB inpercent oftotal pounds a.e. applied inboththe 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% oftotal pounds a.e. applied inthe latter timeframe, and use decreased in Minnesotabetweenthe two time periods. MCPB use increased in Idaho to 18% oftotal pounds applied inthe 2008-2012 timeframe.


### Table 2. Comparison ofStates with Highest Use ofMCPB- Percent ofTotalLbs. Applied Between the2003-2007 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 bl 3 MCPBU

a e . seon 

### T C op rops, 2008 2012 

# - Crop Average Pounds Average TotalAcres 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 ProprietaryData, 2008-2012


### CHEMICAL AND USE CHARACTERISTICS MCPB is a synthetic auxin herbicide inthe Weed Science Society ofAmericaherbicide group four. The mechanism ofaction ofthis herbicide is not well understood butthe 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 ofaction ofthis herbicide is to cause abnormal cell growth and elongation atthe growing points and plantnodes, leafattachments, and internodes, the length ofstem between nodes. The abnormal growthresults in a distorted and constricted vascular system and ultimately total blockage ofthe vascular system. Phytotoxicity ofMCPB comes from the translocation ofthe herbicide inthe 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 ofresistant weeds.


### ROLE OF MCPB IN PEST MANAGEMENT This herbicide is primarily usedto control the invasive noxious perennial weed Canadathistle following emergence ofthe weed. This weed is considered a noxious weed inmany states and is required by lawto be controlled. Canadathistle is a very important weedto control in any crop especially in broadleafcrops 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 canbe an important herbicide for use in peas for the control ofthis weed.


### DATANEEDS 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 ofMCPB.

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### REFERENCES BEAD, 2013. MCPB Screening Level Usage Analysis. Biological and Economic Analysis Division, Office ofPesticide Programs, US Environmental Protection Agency. February 15. Heap, I. 

### The International Survey ofHerbicide Resistant Weeds. Online. Internet. Wednesday, August 14th, 2013. Available www.weedscience.com Nickerson, C., R. Ebel, A. Borchers, and F. Carriazo. 2011. Major Uses ofLand in the United States, 2007. USDAIERS. Economic Information BulletinNumber 89. Proprietary Data. 1998-2012. (pesticide usage data) Senseman, 

### Sed. 2007. Herbicide HandbookNinth Edition. Weed Science Society ofAmerica. 810 E. lOth street. Lawrence, KS 66044-8897. U.S.A. US Census. 2012. Statistical Abstract ofthe 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 ofAgriculture. Online: http://www.agcensus.usda.gov/Publications/2007/index.asp
. USDA, 2007. Census ofAgriculture. (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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