### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WAS HfNGTON D. C. , 20460


### APR 

## 15 2014 OFF I CE OF C H E MI CAL SAFETY AND P OLLUTION PRE V

ENTION


### MEMORANDUM

SUBJECT :
FROM:

THRU: Use!Usage Refinement in Support of Registration Review of Lactofen (PC128888) Sunil Ratnayake, Biologist

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# n Biological Analysis Branch

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Andrew Lee, Economist Economic Analysis Branch 

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Ra fae l Prieto, Environmental Protection Specialist

# ~**~** Science Information and Analysis Branch Biological and Economic Analysis Division (7503P) Arnet Jones, Chief Biological Analysis Br c Tim Kiely, Chief

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# ~ Economic Analysis Branch \)

### A**V~\;** Diann Sims, Chief

# ~ Science Information and Analysis Branch Biologica l and Economic Analysis Division (7503P) 

### TO: Kelly Ballard, Chemical Review Manager Neil Anderson, Chief Risk M anagement and Implementation Branch I Product Re-evaluation Division (7508P)
Product Review Panel: March 26, 2014

1SUMMARY Lactofen is in the proposed decision making phase of registration review. In response to PRD's request, BEAD is providing refined use/usage information to help with risk decisions. Lactofen is registered for use as an herbicide on several use sites including snap beans, soybeans, cotton, kenaf, and forestry (non-food use) for both pre- and post-emergent control ofbroadleaf weeds. Soybeans and peanuts are the major crops that use lactofen. In recent years, less than 1% and 2.5% of soybeans and peanuts, respectively, were treated with lactofen. The data indicate that in the vast majority of cases (state/year combinations), a single application of lactofen is made per year. The 98th percentile ofapplication rate for soybeans, by far the largest lactofentreated crop, and for peanuts is 0.2 pounds a.i. per acre. Lactofen is not registered for residential use . Lactofen may be used as a tank-mix partner with glyphosate in soybeans to manage glyphosateresistant weeds such as kochia (Kochia scoparia), and common waterhemp (Amarantus rudis) (South Dakota State University, 2013). Lactofen provides a wider window ofherbicide application than many other herbicides and it can be applied as a pre-plant pre-emergence or a post-emergence treatment (University of Illinois, 2008). In no-till soybean production, lactof en may be used as a burn-down treatment against glyphosate-resistant waterhemp (Amarantus rudis) (University of Illinois , 2008). Lactofen can also be used in soybean for the suppression of white mold at low application rates (Hauf and Grafton, Undated; Iowa State University, 1998).
BEAD'S REFINED USE/USAGE DATA Use/Usage Overview: Major Crops Treated. Percent Crop Treated (PCT), and Total Acres Treated (TAT) Table 1 provides an overview of lactofen usage. Soybeans, peanuts, and cotton are the major crops that use I actofen in terms of total area treated with the chemical. 

### Table 1. 

### Lactofen major use sites, percent crop treated (PCT), and total area treated. Crop PCT* Soybeans <1% Peanuts <2.5% Cotton < 1% Source: EPA propnetary data, 2013. *EPA BEAD, 2011. Total area treated (TAT), 1,000 acres %TAT 1 ,000 95%

42 4% 4 .8 0.4%

OPP's Screening Level Usage Analysis (SLUA) indicates that less than 1% of soybean acreage is treated with lactofen (EPA BEAD, 2011). However, EPA proprietary data (2013) shows that on average (over 2008-20 12), this 1% (-one million acres) represents 95% ofthe total acres treated with lactofen in the U.S. annually. For peanuts, the next largest lactofen crop, percent crop treated is less than 2.5% (-42,000 acres), accounting for approximately 4% of the annual totallactofen treated acres in the U.S. Thus, soybeans and peanuts together represent 2approximately 99% of the total acres treated with lactofen in the U.S. , annually. The remaining**1%** are due to cotton (4,800 acres), beans (snap, bush, pole, string) (3,700 acres) , com (3 , 300 acres), dry beans/peas (1,000 acres), sweet corn (200 acres), and peas (fresh/green/sweet) (<50 acres) (EPA proprietary data, 2013 ). These data indicate that the largest use of lactofen is on soybeans, both in terms ofabsolute number of acres treated and the proportion ofthe total areas treated in the U.S. Florida Vegetables The use of lactofen on Florida vegetables has been iden tified as an ecolo gical risk driver; therefore, BEAD obtained further information on this usage. Lactofen use on Florida vegetables is registered under FIFRA section 24 (c) , Special Local Need (SLN). EPA proprietary data (2013), which includes use ofSLN products, shows no usage for Florida vegetables for 1998- 2012. This suggests little or no lactofen usage on Florida vegetables. AerialApplication According to EPA pr oprietary data (20 13), aerial application is not an important application method for any lactofen-treated crop. Lactofen has not been applied aerially to soybeans after 1 998. There was only one other instance of aerial use which was less than 5,000 a cres in 2010 on dry beans/peas. Average Application Rates
. Rate Distributions, and Number o[Applications Information on the application rates will be helpful to characterize both the human health and ecological risk assessments. The national average (2008

-2012) application rates used by growers were obtained from the EPA proprietary data (2013) and compared to the maximum label rates. Table 2 compares the average application rates for soybeans, peanuts, and cotton (the top three lactofen crops in terms oftotal acres treated) to the maximum label rates, which ar e the rates EFED used in its ecological risk assessment (EPA EFED, 2013. p.l9 , Table 3.1). T bl 2 N . 

### r

a e 

# . atlona avera2e application rates, 2008 2012 

## - 

# . Label rate Label rate (max per Average (max single season 98th Percentile application rate 1
, application), application), Comparison to label max application rate 1 lb Crop lb a.i./acre lb a. i./acre lb a.i./acre single application a.i./acre Soybeans 0
. 12 0.2 0.4 Label rate is -1
.7x avg rate 0.2 Peanuts 0
. 17 0.2 0.4 Label rate is -1. 2x avg rate 0.2 Cotton 0.09 0.2 0.4 Label rate is -2
.2x avg rate 0.15 I EPA propnetary data (20 I 3) In addition to average application rates, the 98th percentile of application rates applied on soybeans, peanuts, and cotton were obtained from EPA proprietary data (2013). For the period 1998 to 2012, the 98th percentile application rate was 0.2lbs a.i. per acre for soybeans , 0.2lbs a.i. per acre for peanuts, and 0.15 lbs a.i. per acre for cotton. 3BEAD also estimated the typical number of applications of lactofen for soybeans and peanuts. The number of applications per year for each crop was calculated by dividing the tota l acres treated (TAT) by the base acres treated (BAT) from EPA proprietary data (20 13). For the period 1998-2012, more than 98 percent of peanut acreage treated with lactofen and more than 99 percent of soybean acreage treated with lactofen received one application per year. 

### REFERENCES EPA BEAD, 2011. Screening Level Usage Analysis (SLUA), 2011. B iological and Economic Analysis Division, Unpublished EPA report. EPA EFED , 2013. Preliminary Environmental Fa te and Ecological Risk Assessment in Support ofthe Registration Review of Lactofen
. Environmental Fate and Effects Division, Unpublished EPA report. March 13 , 2013. EPA Proprietary Data, 2013. Hauf, D.C. and K. F.Grafton, Undated. Suppression of white mold in dry bean with lactofen applicat ions. Online Publication ofNorth Dakota State University. Available at: http: //naldc.nal.usda.gov /download/IND23299645 /PDF Verified: April 3, 2014. Iowa State University, 1998. Cobra for white mold suppression. University Extension. Integrated crop management-480(14). Available at: http: //www.ipm.iastate.edu/ipm /icm/1998/6- 15-1998/cobra.html. Verified : April3, 2014. South Dakota State University, 2013. South Dakota 2013 Crop Protection Guide for Soybeans. Available at: http: /ligrow
.org/up/resources/03-3000-2013 l.pdf
. Verified: March 2 1,2014. University of Illinois, 2008
. Recommendations for management of glyphosate-resistant waterhemp in Illinois soybean. Available at: http: //weeds.cropsci.illinois.edu/extension/factsheets/whempsoy.pdf. Verified: March 21 , 2014.

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