UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

W ASHfNGTON D.C., 20460 

APR 15 2014 OFFICE OF CHEMICAL 

SAFETY 

AND POLLUTION 

PREVENTION 

MEMORANDUM 

SUBJECT: 

FROM: 

THRU: 

U se!U sage Refinement in Support of Registration Review of Lactofen 

(PC128888) 

Sunil Ratnayake, Biologist (~-~ - \._ n 

Biological Analysis Branch _~ ~;'TJ . LfVVL-.----

Andrew Lee, Economist 

Economic Analysis Branch a+ck 

Ra

Science 

fael Prieto, 

Information 

Environmental 

and Analysis 

Protection 

Branch 

Specialist ~ ~ 

Biological and Economic Analysis Division (7503P) 

Arnet Jones, Chief 

Biological Analysis Br c 

Tim Kiely, Chief ~{ A ~ Economic Analysis Branch \) A V~\; 

Science 

Diann Sims, 

Informa

Chief 

tion 

~ and Analysis Branch 

Biological and Economic Analysis Division (7503P) 

TO: Kelly Ballard, Chemical Review Manager 

Neil Anderson, Chief 

Risk Management and Implementation Branch I 

Product Re-evaluation Division (7508P) 

Product Review Panel: March 26, 2014 

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SUMMARY 

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 of application 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 of herbicide 

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, lactofen 

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 acto fen 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% of the 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 

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approximately 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 of absolute number of acres treated and the proportion of the total areas 

treated in the U.S. 

Florida Vegetables 

The use of lactofen on Florida vegetables has been identified as an ecological 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. 

Aerial Application 

According to EPA proprietary 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 

1998. There was only one other instance of aerial use which was less than 5,000 acres 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 of total acres treated) to the maximum label rates, which are the rates 

EFED used in its ecological risk assessment (EPA EFED, 2013. p.l9, Table 3.1). 

T a bl e 2 N . . atlona avera2e application r rates, 2008 -2012 . Label rate 

Label rate (max per 

Average (max single season 98th Percentile 

application rate1

, 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. 

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BEAD 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 total 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. Biological and Economic 

Analysis Division, Unpublished EPA report. 

EPA EFED, 2013. Preliminary Environmental Fate and Ecological Risk Assessment in Support 

of the 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 

applications. Online Publication of North 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 21,2014. 

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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