UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D

.C

. 20460 

### NOV 0 6

### 2014

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM SUBJECT:
FROM:

THRU:

TO: BEAD Chemical Profile (BCP) for Registration Review: Diuron (035505)
Sunil Ratnayake, Biologist Biological Analysis Branch

# ~h**~**...

# V'~

# '1-~ SepehrHaddad, Environmental Protection Specialist Science Information and Analysis Branch Stephen Smearman, Economist

. /' ./ 

### I 

# tJ Economic Analysis Branch

## ~~ Biological and Economic Analysis Division (7503P) ArnetJones, Chief 

### Biological Analysis Branch. 

# j)

. DiannSims,Chief

# ~~**In ,j,~**  Science Information ana Analysis Iifanch t Timothy Kiely, Chief

# ~**~** Economic Analysis Branch 

## lA.\, Biological and Economic Analysis ivision ( 503 ) Kathrine St. Clair, Chemical Review Manager, RMIB II Pesticide Re-evaluation Division (7508P)


### Peer Review Panel date: October 15, 2014

### SUMMARY Diuron was first registered in the United States in 1967 and it is used as a pre and post-emergent herbicide, algaecide, and mildewcide (USEPA, 2003). Diuron is a broad-spectrumresidual herbicide registered for control ofbroadleafand annual and perennial grassy weeds. Inthe U.S., diuron is registered for the control ofweeds in agricultural crops (see use sites below). Also, it is used in non-agricultural sites such as irrigation and drainage systems, industrial and rights of way uses, and total vegetation control where it is used in combination with other herbicides. A Screening Level Usage Analysis (SLUA) was preparedby BEAD for this chemical in 2014 that provides the percent crop treated for 31 crops. For diuron, during the SLUA timeframe of 2004-2012, usage for cotton and oranges had the highest use interms ofaverage pounds active ingredient (a.i.) used with 1.4 million lbs a.i. for cotton with an average 25 percent crop treated, and 1.2 million lbs a.i. for oranges with an average percent crop treated of45 percent. The highest percent crop treated overthe SLUAtimeframe is for asparagus with an average 65 percent crop treated. These percent crop treated numbers for cotton, oranges and asparagus may indicate high benefits ofdiuron for these crops. 

### INTRODUCTION The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an overview ofthe pestmanagementroles and quantitative usage information for diuron. The BCP includes summaries ofprevious BEADproducts and available public and/or private use and usage data for diuron to describe the role ofthis chemical inpestmanagement. Additional information on use is available the LUIS Label DataReport and Screening Level Usage Analysis (SLUA). Information provided inthis BCP may be used by stakeholders (e.g., users and registrants), OPP risk andbenefit assessors, OPP risk managers, and the general public during the Registration Review process ofthis pesticide. 

### USE SITES Agricultural Use Sites Diuronregistered agricultural use sites include: alfalfa, apples, artichokes, asparagus, bananas, barley, caneberries, citrus, clover, com, cotton, grapes, nuttrees, mint, oats, papayas, pasture, peaches, pears, peas, pineapple, sorghum, sugarcane, ornamental trees, flowers and shrubs and wheat. Non-Agricultural Use Sites Diuronregistered non-agricultural use sites include: paints and coatings; adhesives, ornamental fish ponds, and catfishproduction; patios, rights-of-way and industrial sites. Residential uses include ponds, aquariums, and paints.

Page2FORMULATIONS AND APPLICATION METHODS Diuron is formulated as a liquid, emulsifiable concentrate, dry flowable, flowable concentrate, pellet/tablet, andready-to-use solution. Applications are made using the following equipment: ground sprayer, aerial equipment, and chemigation. HISTORY OF DIURON and BEAD PRODUCTS Diuron was first registered in the United States as a pre and post-emergent herbicide, algaecide and mildewcide in 1967 (USEPA, 2003). A Reregistration Eligibility Decision (RED) was completed for diuron in2003. Benefits Assessments - A search ofBEAD's Official Records data base for BEAD benefits assessments specifically for diuron did not find any records ofprior BEAD assessments specifically for this chemical inthe last 1 0 years. A Screening Level Usage Analysis (SLUA) was prepared by BEAD for this chemical in 2014 that provides the percent crop treated for 31 crops. For diuron, during the SLUAtimeframe of 2004-2012, usage for cotton and oranges had the highest use interms ofaverage pounds active ingredient (a.i.) used with 1.4 million lbs a.i. for cotton with an average 25 percent crop treated, and 1.2 million lbs a.i

. for oranges with an average percent crop treated of45 percent. The highest percent crop treated over the SLUAtimeframe is for asparagus with an average 65 percent crop treated. There were no emergency exemptionrequests for diuron in the last 1 0 years. Emergency exemptions may indicate thatthere is a need for a particular chemical that is not registered for use on a particular site. Anemergency exemptionrequest may yield information about a particular chemical's importance orvalue that is not found in other EPArecords. However, a lack ofSection 18 assessments by BEAD does not specifically indicate the relative importance of the chemical. USAGE Agricultural Usage Based onprivate market usage data from 1998-2012, usage averaged approximately 4.1 million pounds active ingredient (a.i.) applied annually on approximately 4.9 million acres treated. The average a.i. rate overthis time period was pounds 0.84lbs a.i./acre. Figure 1presents diuron usage inpounds a.i. and total areatreated in acres over the 1998-2012 timeframe (Proprietary Data, 1998-2012). Figures 1 shows that overthis time period in terms ofpounds applied and acres treated there has been a modest decline in use although recently there has been a slight increase in the total number ofacres treated from 2010-2012 comparedto the years 2006-2009.

Page 3FIGURE 1. Diuron Usage in Pounds Active Ingredient and TotalArea Treated in Acres (1998-2012)

7,000,000

0**Pounds** AI**Total** Area Treated Source: Proprietary Data, 1998-2012 Since the Re-registration Eligibility Decision was issued in 2003, the two timeframes below (1998-2003 and 2007-2012) were selectedto compare atime periodbefore the RED was issued andthe mostrecenttime period. Table 

### 1. Comparison ofCropswith HighestUse ofDiuron- Percent ofTotalLbs. Applied (1998-2003 and 2007-2012)_ 1998-2003 2007-2012 Average annual=4.7 million lbs/yr Average annual = 3.3 million lbs/yr Crop %Lbs Crop %Lbs Orange 40% Cotton 37% Cotton 29% Orange 35% Grapefruit 6% Alfalfa 8%

Alfalfa 5% Walnuts 4% Sugarcane 4% Grapefruit 3% Other 16% Other 13% TOTAL 100% TOTAL 100% Source: Proprietary Data, 1998 -2012. Table 1 shows thatthe crop with the mostpounds applied during boththe 1998-2003 and 2007- 2012 timeframes have been oranges and cotton accounting for approximately 70 percent oftotal pounds applied. The average annual usage inpounds has decreased approximately 30 percent from 4.7 million lbs/year to approximately 3.3 million lbs/year inthe 2007-2012 timeframe.

Page4

### Table2o Comparison ofStates with Highest Use ofDiuron- Percent ofTotalLbso Applied (1

### 998-2003 and 2007-2012) 1998-2003 2007-2012 Average annual= 

### 4.7 million lbs/yr Average annual= 

### 3.3 million lbs/yr 

### State %Lbs State %Lbs Florida 

### 38% Florida 

### 28% California 

### 17% California 

### 21%

Texas 

### 15% Georgia 

### 13% Louisiana 

### 7% Texas 

### 10% Other 

### 23% Other 

### 28% TOTAL 100% TOTAL 100% Other states in both time periods includes 30 additional states
. Source: Proprietary Data, 1998-2012 As shown inTable 2, Florida, California and Texas were the top states with the highest use of diuron inbothtime frames accounting for approximately 

### 70 percent oftotal pounds applied in the 

### 1998-2003 timeframe, and approximately 

### 60 percent in the latter timeframe, eventhough total pounds applied has dropped 

### 64 percent between the two periods. Application Rates The average a.i. rate for the top crop (cotton) in terms ofpounds a.i. applied was 

### 0.44 lbs a.i./acre. The average a.i. rate for oranges is 

### 1.91 lbs a.i./acre as shown inTable 

### 3. T bl 3 

## n·

a e 0 

### 1uron

# use on

### T C op rops: A

### verageA I R t 2007 2012 0 0 

### a e, 

## - AnnualAverage AnnualAverage Avgo Aolo Rate (lbs Crop Pounds TotalAcres aoi.lacre) Treated* Cotton 

### 1.23 million 

### 2.78 million 

### 0.44 Oranges 

### 1.13 million 

### 593,000 1.91 Alfalfa 

### 278,000 312,000 0.89 *Total Acres Treated sums all acres treated for a crop, mcludmg those acres that receive multiple treatments
. Source: Proprietary Data, 2007-2012 Geographic Distribution ofDiuronUse Figure 3provides a very broad geographical view ofthe average annual amount (inpounds) of diuron appliedper 

### 1,000 acres ofcrop acres grown. The calculated values presented in the map are not equivalent to an applicationrate (lb a.i./A), therefore, the map may show areas ofhigh use intensity that do not correspond to the states listed in Table 2 since those are the states with the highest use ofdiuron based onpounds active ingredient applied. As shown 

### in the map, Florida and NewJersey depict a high use intensity ofacres treated with diuron. Please see Appendix I for a more detailed explanation ofthe information presented on Page 5the map. 

### FIGURE 2. AnnualAverage AgriculturalUse Intensity ofDiuron (2008-2012)

PoundsActive Ingredient per 1,000 Crop Acres Grown 0 <6 0 6-19 

### D 2o-3o

- 31-129

- >129 0NoData

Non-Agricultural Usage Most available non-agricultural usage data for diuron is limited and dated

. There are two data sources for non-agricultural usage. These are the publically available USDA'sNational Agricultural Statistics Service (NASS) 2006 and 2009 Nursery and Floriculture reports, and the proprietary Kline & Company data. In additionto NASS 2006 and 2009 data which reported 2,300 lbs a.i. used in 2006 and 3,300 lbs a.i. used in 2009 for nursery, otherreported data is available from Kline for the years 2002, 2004, 2006 for nursery/greenhouse, 2004 and 2006 for landscape/lawn care operators, and 2003 and 2005 for aquatic areas as shown in Table 4. Total non-agricultural usage between 2003 and 2005 appears to have increased for aquatic areas, and between 2004 and 2006 for nursery/greenhouse, however, morerecent data (post-2006) are not available to determine ifthis trend has continued since only one category ofnon-agricultural usage (turfand ornamentals) was available for 2011 showing 3,700 lbs a.i. used. Page 6

### Table 4. Diuron Non-Agricultural Usage (Pounds A.I) (2002-2011) Site 2002 2003 2004 2005 2006 2011 Aquatic Areas N/A 500 N/A 28,000 

## NIA N/A Landscape/Lawn Care N/A 

## NIA 2700 N/A 6200 

## NIA Operators Nursery/Greenhouse 7100 N/A 5100 N/A 6800 

## NIA Turf& Ornamentals N/A N/A N/A 

## NIA 100 3700 N/A= Not Available Source: Proprietary Data 2002-2011 

### BIOLOGICALASPECTS RELEVANT TO DIURON Diuron is a systemic herbicide belongs to chemical family ofurea (Group 7). Herbicides in this family interfere with photosynthesis. Diuronis primarily applied before the emergence ofthe crop and weeds. Diuron has residual activity and continues to control weeds until the crop become competitive withweeds. Diuron may also be applied as directed post-emergence treatments to avoid contact with crop foliage. Diuron can also be applied as a bum-down treatment to control annual weeds before planting. Diuron is taken up from soil solution by the root system and rapidly translocated into stems and leaves bymoving primarilyviathe xylem.


### ROLE OFDIURON IN PEST MANAGEMENT Diuron is a broad-spectrum herbicide with residual activity and it is registered for the control of broadleafand annual and perennial grassy weeds in agricultural and non-agriculturallands. Cotton and oranges are the top agricultural crops withthe highest usage ofdiuron (Table 3). In cottonproduction, diuron is tank-mixed with bum-down herbicides to achieve a longer residual activity (Steckel, 2014). According to a publication in Georgia, diuron is a unique tool for cotton growers as it offers excellent control ofsmall emerged Palmer amaranth. (Culpepper, 2012). In citrus production, tree growth and yield canbe reduced due to the weed competition. Preemergence application ofdiuron is recommended to minimize these yield reductions (Futch and Sing, 2014). As previously mentioned a SLUA was preparedby BEAD for this chemical in 2014 that provides the percent crop treated for 31 crops. For diuron, during the SLUA timeframe of2004- 2012, for cotton, the percent crop treated was an average of25 percent, and for oranges the percent crop treated averaged 45 percent. The highest percent crop treated overthe SLUA timeframe was for asparagus with an average 65 percent crop treated. These percent croptreated numbers for cotton, oranges and asparagus may indicate highbenefits ofdiuron for these crops. Bermudagrass (Cynodon dactylon), crabgrass (Digitaria ischaemum and D. sanguinalis), goosegrass (Eleusine indica), and Johnsongrass (Sorghum halepense) are major grass weeds controlledby diuron. cocklebur (Xanthium strumarium L),jimsonweed (Datura stramonium), hop hornbeam copperleaf(Acalypha ostryifolia), common lambsquarters (Chenopodium album), Page 7pigweeds (Amaranthus spp.), prickly sida (Sida spinosa), commonpurslane (Portulaca oleracea), commonragweed (Ambrosia artemisiifolia), horseweed (Conyza canadensis) are majorbroadleafweeds susceptible to applications ofdiuron. Most ofthese weeds are found in crop productionfields in the southernUnited States. The majornon-agricultural use sites ofdiuron are roadside vegetation management, industrial sites and other non-agricultural use sites are listed underthe heading ofnon-agricultural use sites ofthis document. Furthermore, diuron has beenused as an algaecide and mildewcide agent in paints. It has been reported that total of 144 weed species identified with resistance to different modes of action ofherbicides in the United States. Ofthese weed species, 9 were found to have developed resistance to the herbicides belongs to family ofurea herbicides. In these 9 weeds, biotypes of5 weed species have shownresistance to diuron herbicide (Heap, Undated). DATANEEDS The Agency currently does not have complete information for diuron for some ofthe herbicide uses and for antimicrobial (algaecide and mildewcide agent) l!Se. Obtaining information onthe annual number ofpounds andthe average rates for applied diuron on a national level for roadside and otherrights-of-way vegetation management uses as well as antimicrobial applicationrates, timing and amount ofactive ingredient used wouldbe helpful to our future assessments. REFERENCES Biological and Economic Analysis Davison (BEAD). USEPA, 2014. Diuron Screening Level Usage Analysis. Biological and Economic Analysis Division, Office ofPesticide Programs, US Environmental ProtectionAgency. 2014 Cotton Weed Control. 2014. Online Publication available at: http://extension.missouri.edu/p/G4251

.Accessed on October 17, 2014. Culpepper, S. 2012. Georgia Cotton: Diuron, Direx Offer Flexibility- But Be Careful. Online Publication. Available at: http://agfax.com/2012/04/04/georgia-cotton-diurun-direx-offerflexibility-but-be-careful/

. Accessed on October 24, 2014. Futch, S. H
.. and M. Singh. 2014. 2014 Florida Citrus Pest Management Guide: Weeds. University ofFloridaIFHS Extension Service PublicationNo. HS-107. Online Publication. Available at: http://edis.ifas.ufl.edu/cg013. Access on October 24, 2014. Heap, I. (Undated). The International Survey ofHerbicide Resistant Weeds. Available at: http://www.weedscience.org/summary/CountrySummary.aspx

.

Accessed Date. September 3, 2014. Herbicide Handbook. 2014. 1Oth edition. Weed Science Society ofAmerica. Sethoxydim. Pp 413-414. 810 E. lOth Street, Lawrence, KS 66044-8897. Page 8Proprietary Data. 1998-2012. (pesticide agricultural usage data).
Steckel, L. 2004. Southeast Farm Press. Online Publication. Available at: http

.:/Isoutheastfarmpress.com/ cotton/residual-cotton-herbicide-options-late-burndowntennessee
. Accessed on Oct, 24, 2014. USDA, 2006 and 2009. NASS Nursery and Floriculture Report. Online Publication Available at: http://quickstats.nass.usda.gov/results/E4B4FA4B-15DB-35DO-A5CD-9889E6D7689F. Accessed on September 3, 2014. USEPA. 2003. Re-registration Eligibility Decision (RED) for Diuron. http://www.epa.gov/oppsrrd1/REDs/diuron red.pdf

.Accessed on Oct. 24, 2014.
Ware, G. W. 2000. The pesticide book. Fifth Edition. Fresno, CA. Thomson Publications. Pp 193-194.

Page 9APPENDIXI. The map included herein is primarily for the use ofthe risk assessors inthe Environmental Fate and Effects Division. The map provides a very broad geographical view ofthe average annual amount (inpounds) ofthe active ingredient applied per 1,000 acres ofcrop acres grown. These data are included in the maps because risk assessors are interested in the amount ofa pesticide used across agricultural land. The calculated values presented inthe map are not equivalent to an application rate (lb a.i./ A). The dataused to make these maps have several limitations. Any interpretation ofthe maps should considerthe underlying data and the associated limitations carefully. The numerator (annual average pounds applied) is based onprivate market surveys ofpesticide use in agriculture averaged overthe last five years (Proprietary Data, 2008-2012). These surveys cover about 60 crops and are targeted in states that produce the majority ofthe crop. Although the surveys capture most ofthe use ofa particular active ingredient in agriculture, there are several limitations to these surveys.

• States with minorproduction ofa surveyed crop are not sampled • Notall types ofpesticides are surveyed in every crop in every year • Many specialty crops with very small acreages are not included inthe survey The result ofthese limitations is that states that show no usage may actually have a small amount ofthe 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 representthe actual pesticide usage onthe crops produced in the state
. The denominator (1,000 crop acres grown) was also obtained from the sameprivate market survey database. The "Crop Acres Grown" variable represents the total acres grown in a given state ofall ofthe surveyed crops. This value is independent ofpesticide usage andpesticide registration. Itis importantto note thatthe surveyed crops (about 60) are sampled from states that are majorproducers ofeach crop. Therefore, there are cases where the actual crop acreage in a state is higherthanthat reported by crop acres grown in the survey because eitherthat state and/or crop was not included inthe survey. The reader should pay particular attentionto 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.

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