UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

JUN 17 2Dt5 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: Flumetralin (123001) 

FROM: 

THRU: 

TO: 

Leonard Y ourman, Plant Pathologist f 

Biological Analysis Branch (j 1 

Arnet Jones, Chief 

Biological Analysis Branch 

Diann Sims, Chief )fl;...~ Science Information and Analysis Branch 

Biological and Economic Analysis Division (7503P) 

Katherine St. Clair, Chemical Review Manager 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel: June I 0, 20 I 5 

SUMMARY 

Flumetralin is a plant growth regulator that has been registered for use on tobacco since 1983 

(EPA, 2007). It is used to control axillary bud (sucker) growth on tobacco plants. The current 

average total annual domestic usage offlumetralin averages approximately 100,000 pounds active 

ingredient (a.i.) per year. Flumetralin use has increased in recent years possibly due to an attempt to 

reduce maleic hydrazide residues on tobacco. There are no registered food or feed uses for 

flumetralin. 

INTRODUCTION 

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

overview of the pest management roles and quantitative usage information for flumetralin. The 
BCP includes summaries of previous BEAD products and available public and/or private use and 

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

information on use is available in the Flumetralin Label Data Report. Information provided in 

this BEAD Chemical Profile (BCP) may be used by stakeholders (e.g., users and registrants), 

OPP risk assessors, and OPP risk managers, and the general public during the Registration 

Review process of this pesticide. 

HISTORY OF FLUMETRALIN AND BEAD PRODUCTS 

No assessments have been conducted for flumetralin. 

USE SITES 

Agricultural Use Sites 

Flumetralin is only registered for use on tobacco. 

FORMULATIONS 

Flumetralin is formulated as an emulsifiable concentrate. 

APPLICATION METHODS 

Flumetralin is applied as a broadcast, drench, and directed spray. Droplines, power sprayers, 

backpack sprayers, and vehicle propelled sprayers can be used. 

USAGE 

Agricultural Usage 

Usage of Flumetralin has increased steadily, in terms of both pounds a.i. applied and total acres 

treated, more than doubling between 1998 and 2013 (Figure 1 ). 

2 
250,000 

Pounds Al 

Applied & 

Total Acres 

Treated 

0 oo m o M N m ~ ~ ~ ~ oo m o M N m m m 0 0 0 0 0 0 0 0 0 0 M M M M m m o o o o o o o o o o o o o o M M N N N N N N N N N N N N N N 

Pounds Al _._Total Area Treated 

Figure 1. Flumetralin Total Acres Treated and Total Pounds A.I. Applied (1998-2013). 

Source: Proprietary Data, 1998-2013 

The increase in flumetralin usage is particularly interesting when viewed in terms of the overall 

decrease in total acres of tobacco grown. In the time period shown above, 1998-2013, tobacco 

acreage decreased by nearly 55%. In the same time period, however, tobacco acres treated with 

flumetralin increased by 50%. Table 1 shows average usage from 2004-2008 and 2009-2013. 

Between these two time periods, average pounds A.I. applied, total acres treated, and percent 

crop treated all increased approximately 40%, while average application rates remained 

relatively steady. This increase in use of flumetralin may be due to a concern for maleic 

hydrazide residues and the substitute (or partial substitute) of flumetralin in place of maleic 

hydrazide (e.g., Fisher and Stewart, 2010; Gooden, 2012). 

T a e bl 1 . Fl umetra r u m se on T C op rops: A veraee AIR .. ate, 2004 -2008 an d 2009 -2013 

Average Pounds Average Total Average A.I. Percent Crop Years Crop Acres Treated Rate A.I./year /year* (lbs a.i./acre) Treated 

2004-2008 Tobacco 68,000 100,000 0.67 30 

2009-2013 Tobacco 103,000 170,000 0.61 50 

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

Source: Proprietary Data, 2009-2013 

While overall usage has increased, the geographic distribution of application has remained fairly 

consistent. From 2003 to 2007 and 2008 to 2013 over half of flumetralin was applied in North 

Carolina, followed distantly by Kentucky and Virginia, with the remaining 15 percent of usage 

split between six to ten other states (Table 2). 

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Table 2. Comparison of States with Highest Use of Flumetralin -

P ercen t o fT oa t IP oun d s AI . . A ,0011e rd b e tw een 2004 -2008 an d2009 -2013 . 2004-2008 2009-2013 

Average Annual = 68,000 lbs Average Annual= 103,000 

State %Lbs State o/o Lbs 

North Carolina 55 North Carolina 60 

Kentucky 15 Kentucky 15 

Virginia 15 Virginia 10 

South Carolina 5 South Carolina 5 

Tennessee 5 Tennessee 5 

Other* 5 Other* 5 

*Other states: CT, FL, GA, ID, OH, PA, WI, WV *Other states: GA, FL, OH, PA, 

Source: Proprietary Data, 2003-2012 

4 
Geographic Distribution ofFlumetralin Usage 

The map below shows Flumetralin use intensity, in terms of pounds a.i. applied per 1,000 

acres of state crop area grown (Figure 2). As shown in Table 2, usage is highest in the 

tobacco growing states of the southeast. 

Pounds Active Ingredient 

per 1,000 Crop Acres Grown 

c=JNoData 

LJ <0.5 

0.6 - 1.0 

. 1.1-3.0 

- >3.0 

Figure 2. Annual average agricultural use intensity of Flumetralin (2009-2013). 

Source: Proprietary Data 

Figure 2 provides a very broad geographical view of the average annual amount (in pounds) of 

Flumetralin applied per 1,000 acres of crop acres grown. The calculated values presented in the 

map are not equivalent to an application rate (lbs a.i./a), therefore, the map may show areas of 

high use intensity that do not necessarily correspond to the states listed in Table 2 since those are 

the states with the highest use of Flumetralin based on pounds active ingredient applied. 

More information about this map is presented in Appendix A. 

5 
CHEMICAL AND USE CHARACTERISTICS FOR CONTROL OF AXILLARY BUDS 

(SUCKERS) 

Flumetralin is a plant growth regulator used on tobacco for control of axillary bud (sucker) growth. 

Reduction of suckers increases the yield and quality of the tobacco leaves. While not a pesticide, 

effective suckering may help reduce late season tobacco homworm infestations (Crop Profile 

WV, 1999). Flumetralin is used for control of suckers on flue-cured, burley, and cigar tobacco 

plants. Three types of chemicals are used to manage sucker growth in tobacco-systemic (maleic 

hydrazide), contact (fatty alcohols) and locally systemic dinitroanalines (flumetralin and butralin) 

(Crop Profile VA, 2001; Crop Profile TN, 2008). Chemical sucker control has been applied to 

nearly all of tobacco acreage in Virginia and North Carolina (Crop Profile VA, 2001; Crop Profile 

NC, 1999). 

Topping occurs when plants begin to develop a flower bud, generally when the flower bud 

begins to elongate and when 50% of the plants have reached this stage. Tobacco topped at bud 

elongation stage can yield 300 or more pounds per acre compared to tobacco that is topped at full 

bloom (Crop Profile TN, 20_08). Removing the tops of tobacco plants removes the dominant 

effect of the terminal shoot over lateral shoots (suckers), thus allowing rapid growth of suckers. 

Topping is done by hand using a knife with workers generally wearing cloth gloves. Suckercontrol chemicals are applied after topping, usually within two days. Dark tobacco types 

generally have less maleic hydrazide (MH) use and would be substituted with products 

containing butralin, flumetralin and/or fatty alcohols (Crop Profile TN, 2008). Combinations of 

these products are often used to improve sucker control. 

Locally systemic chemicals; such as flumetralin, are not true systemics and must be absorbed at 

the axillary bud. As the sucker grows in the leaf axil, the axillary bud grows away from the leaf 

axil and is out of the path of the chemical as it travels down the stalk. Therefore, suckers must 

not be greater than 1-inch long at the time of application. 

Flumetralin is applied like a contact solution, but not until the plants are in the elongated-buttonto-early-flower stage (NCSU, 2015). This is a few days before MH application. The objective is 

to apply flumetralin so that it touches the small suckers (similar to contact solutions) since, 

unlike MH, flumetralin does not move to sucker buds through the leaves. Flumetralin must first 

wet the suckers like a fatty alcohol contact before it can stop cell division like a systemic 

(contact-local systemic). It has no true contact activity, and the controlled suckers do not tum 

brown or black, but rather look yellow and deformed for several weeks after treatment (NCSU, 

2015). Thorough coverage maximizes the effectiveness of flumetralin. Some applications 

including dropline and jug applications (see below) are labor-intensive with workers in close 

contact with the chemical. 

Application of flumetralin (from Fisher and Stewart, 2010) 

Because flumetralin needs to run down the stalk and wet the suckers, it should be applied with 

contact nozzles (TG3 -TG5-TG3 per row or equivalents), with a 50 gallon per acre delivery 

volume, and at a low pressure (20 to 25 psi). Flumetralin does not completely control suckers 

longer than I inch, so you should remove larger suckers before application. Full-season sucker 

control can be expected on small suckers wetted by the flumetralin solution, but missed suckers 

6 
will continue to grow and should be removed by hand. Missed leaf axils with flumetralin are 

typically in the top of the plant and may result from leaning stalks, leaves covering the leaf axil, 

or both preventing proper "rundown" of flumetralin into the leaf axil. 

Even though the flumetralin label allows for application up to one gallon per acre, the general 

recommendation has been for application rates of 2 quarts per acre. Increasing flumetralin rates 

from 2 quarts per acre to 3 quarts or 1 gallon in a single mechanical application has not 

consistently improved sucker control, primarily because control is so dependent on coverage of 

all leaf axils, which is not improved by increasing flumetralin rates. 

However, application of 2 quarts of flumetralin followed by 1 quart of flumetralin seven days 

later improves sucker control compared to 3 quarts of flumetralin applied in a single application. 

This would indicate that increasing rates of flumetralin above 2 quarts per acre is only 

advantageous if the flumetralin is applied in a split application. It is likely that split applications 

reduce the number of missed leaf axils-the main cause of poor sucker control when MH is not 

used. 

Dropline Application 

Drop line applications are generally the most effective way to apply flumetralin because they 

allow for the most consistent ability to apply the flumetralin solution to each leaf axil. However, 

dropline applications require more labor, which is not always available on the farm depending on 

the scope of the farming operation and/or the degree of mechanization of other farming 

operations. Even though the best sucker control from flumetralin is achieved with dropline 

applications, growers must make the decision on whether such application methods are feasible 

and practical on a case by case basis depending on their individual situations. 

A dropline application is made manually, with a single line per row, coming off of a powered 

sprayer (typically a high clearance sprayer). Multiple lines can be used at one time and each line 

has a valve (trigger) and a single TG nozzle. Flumetralin is then applied on a plant by plant basis 

by manually holding the nozzle over the center of the plant and opening the valve or "trigger" 

long enough to apply a desired amount of solution to each plant. Dropline applications should be 

initiated when approximately half of the plants are in the elongated bud to early-flowering stage. 

Plants should be topped and then flumetralin applied within 24 hours. In many cases, both 

topping and applying flumetralin with a dropline can be accomplished at the same time. Where 

uniformity is a problem and some plants are later to mature, a second trip through the field to top 

and dropline flumetralin only on those plants may be needed. If a second trip is needed, it can 

usually be accomplished at a faster speed than the original dropline application. 

Only apply flumetralin with a drop line once per plant per season. Another advantage of drop line 

applications is that they can reduce the need for contact applications because dropline 

applications of flumetralin can be made at topping. In many cases contact applications, when 

used in conjunction with a drop line application of flumetralin, are only used to allow the crop to 

"even out" so that all plants are at the correct stage for flumetralin application and only one trip 

across the field with droplines is needed. Contacts may also be used in this scenario to delay 

flumetralin applications for better management of labor resources by controlling sucker growth 

until labor is available: In a dropline application, flumetralin should be mixed the same as with 

mechanical applications, 2 to 3 quarts of flumetralin in 49.5 to 49.25 gallons of water, 

respectively. The flumetralin solutions should be applied alone to deliver 1/2 to 213 of a fluid 

ounce of solution per plant. Drop line applications of flumetralin require personal protective 

7 
equipment (PPE) to be worn by workers. Read the label for each source of flumetralin carefully 

(Prime+, Flupro, Drexalin Plus) to determine the requirements for dropline applications. 

Sucker control of flue-cured tobacco are usually addressed by using one of two options (e.g., 

Crop Profile VA, 2001): 

1. Sequential control with two contact applications followed by MH or MH and flumetralin 

in a tank-mix applied over the top as a foliar spray; or 

2. Individual plant methods where plants are treated individually with a 2% flumetralin 

application once, making the application down the stalk with jugs or drop lines. 

Sucker control in burley tobacco is different in that contacts are not generally used and MH or 

MH + flumetralin or MH + butralin is applied once. Sucker control is easier with burley tobacco 

since the crop is harvested 3 to 5 weeks after topping compared to flue-cured which requires 1 O+ 

weeks of control (Crop Profile VA, 2001). 

Acres treated with chemical growth regulators were estimated for the 2007-season (Table 3). 

Because of MH residues found in cured tobacco state extension has recommended closely 

following MH label warnings or the use of another chemical, such as flumetralin, for sucker 

control (e.g., Crop Profile TN, 2008; Fisher and Stewart, 2010; Gooden, 2012). 

Table 3. Estimated Growth Regulator Percent Acres Treated (2007) Tobacco Production 

Active Ingredient Burley Tobacco Dark Tobacco 

(% Acres Treated) (% Acres Treated) 

Butralin* 25 40 

Maleic hvdrazide 90 20 

Flumetralin* 35 60 

Fatty alcohols 30 70 

Source: Crop Profile TN, 2008. 

* Products containing butralin or flumetralin are often used in conjunction with maleic hydrazide. 

REFERENCES 

BEAD. 2015. Flumetralin Screening Level Usage Analysis. Biological and Economic 

Analysis Division, Office of Pesticide Programs, US Environmental Protection Agency. 

Crop Profile NC. 1999. Crop Profile for Tobacco in North Carolina. 

http://www.ipmcenters.org/ cropprofiles/ docs/N Ctobacco. pdf 

Crop Profile TN. 2008. Crop Profile for Tobacco Production in Tennessee. 

http://www.ipmcenters.org/cropprofiles/docs/TNtobacco2008.pdf 

Crop Profile VA. 2001. Crop Profile for Tobacco in Virginia. 

http://www.ipmcenters.org/cropprofiles/docs/vatobacco.pdf 

8 
Crop Profile WV. 1999. Crop Profile for Tobacco in West Virginia. 

http://www.ipmcenters.org/cropprofiles/docs/WVtobacco.pdf 

EPA. 2007. Registration Eligibility Decision Flumetralin. Prevention Pesticides and 

Toxic Substances, US Environmental Protection Agency. 

http://www.epa.gov/pesticides/reregistration/REDs/flumetralin red.pdf 

Fisher, L. and Stewart, S. 2010. Recommendation for controlling suckers without using 

MH. North Carolina State University Extension, Dept. of Crop Science. 

http://www.ces.ncsu.edu/files/library/39/Recommendations%20for%20Controlling%20S 

uckers%20without%20Using%20MH.pdf 

Gooden, D. 2012. Tobacco sucker control. South Carolina Pest Management Handbook 

for Field Crops, 2012. Pp 257-260. Clemson University Extension. 

http://www.clemson.edu/ extension/rowcrops/pest/files/2012%20PMH%20 W eb%20Page 

%20Version/2012%20PMH TOBACCOSC.pdf 

NCSU. 2015. Topping & sucker control-Chemical sucker control. North Carolina State 

University Extension. http://tobacco.ces.ncsu.edu/topping-sucker-control-chemicalsucker-control/ 

Proprietary Data. 1998-2013. (pesticide usage data) 

9 
APPENDIX A 

The map included herein is primarily for the use of the risk assessors in the Environmental Fate 

and Effects Division. The map provides a very broad geographical view of the average annual 

amount (in pounds) of the active ingredient applied per 1,000 acres of crop acres grown. These 

data are included in the maps because risk assessors are interested in the amount of a pesticide 

used across agricultural land. The calculated values presented in the map are not equivalent to 

an application rate (lb a.i./A). 

The data used to make these maps have several limitations. Any interpretation of the maps 

should consider the underlying data and the associated limitations carefully. 

The numerator (annual average pounds applied) is based on private market surveys of pesticide 

use in agriculture averaged over the last five years (Proprietary Data, 2008-2012). These surveys 

cover about 60 crops and are targeted in states that produce the majority of the crop. Although 

the surveys capture most of the use of a particular active ingredient in agriculture, there are 

several limitations to these surveys. 

• States with minor production of a surveyed crop are not sampled 

• Not all types of pesticides are surveyed in every crop in every year 

• Many specialty crops with very small acreages are not included in the survey 

The result of these limitations is that states that show no usage may actually have a small amount 

of the active ingredient being used. In some cases the displayed use intensity may be distorted 

because the surveyed crops and the reported pesticide usage may not accurately represent the 

actual pesticide usage on the crops produced in the state. 

The denominator (1,000 crop acres grown) was also obtained from the same private market 

survey database. The "Crop Acres Grown" variable represents the total acres grown in a given 

state of all of the surveyed crops. This value is independent of pesticide usage and pesticide 

registration. It is important to note that the surveyed crops (about 60) are sampled from states 

that are major producers of each crop. Therefore, there are cases where the actual crop acreage in 

a state is higher than that reported by crop acres grown in the survey because either that state 

and/or crop was not included in the survey. 

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 as 

the legend bins will likely be different. 

10