UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON , D,C

. 20460 

## APR I! 2012

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM SUBJECT: BEAD Chemical Profile for Registration Review: Norflurazon (l05801)'
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TO: Sunil Ratnayake, Biologist

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# r**~~** Jihad Alsadek, Economist 

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# ~**rr~** Science Infonnation and Analysis Branch DerekBerwald, Economist 

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# 0 Biological and Economic Analysis Division (7503P) Arnet Jones, Chief Biological Analysis Branch Diann Sims, Chief

# ~~~ Science Infonnation and AnalQYSiS Branch """'- Timothy Kiely, Chief
. Economic Analysis Branch Biological and Economic 

### AnalysIS

# ivi~ Jack Brennan, Chemical Review Manager Risk Management and Implementation Branch 4 Pesticide**Re-ev~uation** Division (7508P)


### Product Review Panel date: March 14,2012 INTRODUCTION The purpose ofthis document is to convey usage infonnation and a broad overview ofthe pest management roles ofpesticides that are beginning to undergo registration review. The anticipated audience consists ofthe team ofEPA staffcurrently evaluating the registration status ofnorflurazon and eventually the general public. This document builds uponthe data already provided 

### inthe "Usage and Label Use DataPackages" that are also providedto RegistrationReview teams by BEAD. The document is based on information and data available t9 BEAD as ofMarch 7, 2012. Norflurazon was fITst registered as a pesticide inthe U. S. 

### ill 1974 (USEPA, 1996). Norflurazon belongs to,.the pyridazinone herbicide family. Itinterferes with carotenoid synthesis and causes chlorophyll depletion which inhibits photosynthesis in susceptible weeds. Itis applied as a preemergence treatment to control grasses and broadleafweeds inmany agricultural and nonagricultural

### sit**s** which are described below.
. COMMON FORMULATIONS AND APPLICATION METHODS Norflurazon is formulated as water dispersible granules and water soluble concentrate. This herbicide can be applied using tractor mounted ground sprayers and it should notbe applied through any type ofirrigation system. Norflurazon can be applied aerially withthe use ofdrift control measures. 

### USE SITES Agricultural Use Sites Norflurazon is labeled for use onbushberry, cane berry, grapes, citrus, nut crops, pome fruits, stone fruits, hops, asparagus, alfalfa, avocado, cotton, peanuts, soybeans, wheat, pasture, and uncultivated agricultural areas. Non-Agricultural Use Sites Norflurazon is labeled for use on ornamental plants, woody shrubs, trees, and non-agricultural areas. USAGE Agricultural The long term average use for the period 2000-2010 is about 915,000 lbs. a.i. peryear onabout 609,000 acres for an average rate ofabout 1.5 lbs. a.i. per acre. Over this time period, oranges have been the largest use site with about 45% ofthe amount used. Cotton, almonds, and apple each have accounted for 8-9% ofthe pounds applied, see Figure 1. Use may have stabilized over the last five years (2006-2010), see Figure 2. Total use ofnorflurazonhas been declining and the decline appears to be common across all crops although with some variation. Comparing the 2000-2005 period to the 2006-2010 period (Figure 2), we can see that use on cotton declined over 90%, use on almonds declined over 60%, and use on oranges declined about 40%. Note that between the same periods, cotton acreage declined by 23%, orange acreage declined 16%, and almond acreage grewby 26%. (Calculated from Proprietary Data, 2000-2010).



### 2

### Figure 1. 

### Agricultural Usage Data for Norflurazon in Pounds Active Ingredient (2000- 2010)

PoundsA.I. 700,000 

# -r--------- --------------

o 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years • Almonds • Apples
• Cotton • Oranges
• Other

Other crops include grapefruit (4%), wine grapes (3%), raisin grapes, plums/prunes, and peaches (2% each), walnuts, pears, and cherries (1 % each). Source: Proprietary Data, 2000 -2010 

### Figure 2. Usage in Pounds Active Ingredient for Norflurazon, All Crops, 2000-2010. 2,500,000 ..-------------------------------

PoundsA.I.**o"+--~r--~--~--~-_,--_r--,_--r_-~--~-__,** 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years Other crops include grapefruit (4%), wine grapes (3%), raisin grapes, plums/prunes, and peaches (2% each), walnuts, pears, and cherries (1% each). Source: Proprietary Data, 2000 -2010 From 2006-2010, the annual total agricultural usage ofnorflurazon averaged approximately 540,000 pounds active ingredient (a.i.) for 300,000 treated acres with an overall application rate of 1.7 lbs. a.i. per acre. Applicationrates have gone up over time. Data showrates on individual crops are not changing and this is due to a shift inthe crop mix. Use on cotton, with a very low


### 3rate has all but disappeared, while the use on oranges which has a high rate has become a larger share ofuse. (proprietary Data, 2006-2010). Figure 3 provides usage data for 2006-2010. During this period, the use ofnorflurazon on almonds and apples mildly fluctuated. The use on oranges peaked in 2009. BEAD could not identify exact factors which contributed to these changes in usage. For other crops, use varied from year to year, butthere was no clear upward or downward trend. 

### Figure 3. Agricultural Usage Data for Norflurazon in Pounds Active Ingredient (2006- 2010)800,000 

# -r----------------------

PoundsA.I.



### o 2006 2007 2008 Years 2009 2010 • Alfalfa • Almonds • Apples • Oranges • Other

Other crops include wine grapes (4%), grapefruit and raisin grapes (3% each), peaches, pears and cotton (2% each), cherries, and plums, prunes, and walnuts (1% each). Source: Proprietary Data, 2006-2010 During this time frame, the crops with the most use interms oftotal pounds ofactive ingredient applied are oranges (56%), apples (11%), almonds (7%), and alfalfa (6%). The crops withmost total area treated (TAT) are oranges (43%), alfalfa (12%), apples (11%), and almonds (10%). Since the percent ofpounds appliedto oranges is greaterthan the percent ofareatreated, we can inferthat the applicationrate on oranges is higher thanthe overall average. In contrast, the application rate on almonds is lower thanthe overall average since the share ofacres treated is larger than the share ofpounds applied. The higherrate used on oranges is largely behind the increased average rate as oranges now make up a higher percentage ofuse. On average, the states withthe most agricultural usage interms ofpounds a.i. applied are Florida (53%), California (26%), and Washington (11 %). (proprietary Data, 2006-2010). 

### 4

### Use Intensity Another measure ofusage is the use intensity. In this analysis, the use intensity is expressed as the pounds a.i. applied per acre ofland in farms. This differs from the application rate, which is expressed as the pounds a.i. applied pertreated acre. Figure 4 represents norflurazon's use intensity inthe US. The most intense use ofnorflurazon appears to be in Florida and California with small areas ofintense use also reported for NewJersey and New York. 

### Figure 4. Norflurazon Usage by 

### Crop Reporting District (2006

- 2010)

Average Pounds Per 1,000 Acres of Farmland

_ <1.4

. 1
. 4-3
. 5 0 3
. 6-65 6
. 6-12
. 0 12
. 1 - 50

Source: Proprietary Data, 2006-2010 N 

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This is a map ofagricultural pesticide usage at the Crop Reporting District (CRD) level. CRDs are boundaries created by USDA NASS which are aggregates of counties (USDA, 2010). Pesticide usage is displayed as average pounds (for the years 2006-2010) per 1,000 acres of farmland in a CRD to normalize for the variation in farmland between CRDs. Farmland acreage was obtained from USDA (2007). Usage is based on private market surveys ofpesticide use in agriculture (Proprietary Data, 2006- 2010). The survey data are limited to the states that represent the top 80-90% ofacreage for the individual crops; therefore, use may be occurring inregions outside the scope ofthe survey. CRDs showing no usage ofpesticides may be due to either the lack ofpesticide use inthe region or nonparticipation in the agricultural surveys. In addition, across the years, there may be variations in 5the specific crops included in the CRD survey. This may result in a lower annual average for the CRD. Non-Agricultural In 2003, the reported non-agricultural use ofnorflurazon included 900 lbs. a.i. on all nurseries and floriculture, and 400 lbs. a.i. each for nursery propagation and cut cultivated greens. Usage for deciduous flowering trees totaled 2,000 lbs. a.i. with an application rate of3.0 lbs. a.i. per acre. In 2006, the use ofnorflurazon was 4,200 lbs. a.i. on all nurseries with an application rate of3.0 lbs. a.i. per acre. (USDA Agricultural Chemical Usage Nursery and Floriculture Summary) BIOLOGICAL ASPECTS RELEVANT TO NORFLURAZON Norflurazon can be applied as pre-plant incorporated and pre-emergence surface applications. Application ofnorflurazon on stressed cotton, peanut, or soybean plants at the early stage of development can cause temporary bleaching ofleaves. Norflurazon belongs to the mechanism of action ofgroup 12 (inhibition ofcarotenoid synthesis) under the WSSA classification and it has beenreported that certainbiotypes ofhydrilla (Hydrilla verticillata) have developed resistance to this mode ofaction in the United States (Heap et aI., 2012). However, observed resistance was not specifically for norflurazon and presence ofterrestrial weed specie withresistance to the mode ofaction ofthis herbicide is notreported in the United States (Heap et aI., 2012). HISTORY OF BEAD ASSESSMENTS FORNORFLURAZON There is no record ofprior BEAD assessments for norflurazon, so the relative importance of norflurazon to weed control has not been evaluated. However, the concentration ofuse in orange and almond suggest that noflurazon maybe be important to these crops, even though the percent ofthe crop treated is notparticularly high. Another crop with relatively high percent ofthe crop treated is blueberry, which may indicate a niche use for noflurazon. DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON NORFLURAZON Additional infonnation onnorflurazon's use on ornamental plants, woody shrubs, trees, and aquatic sites, uncultivated agricultural and non-agricultural areas, such as pounds active ingredients used and application rates, would improve future BEAD assessments ofthe importance ofnorflurazon and may be needed as part ofthe registration review ofthis pesticide. REFERENCES: Heap, I, H. Glick, L. Glasglow, and W. Vencill. 2012. Herbicide Resistant Weeds by Country and Site ofAction. 2012. http://www.weedscience.org/summary/countrysummary.asp Proprietary Data, 2000-2010. USDA. 2004. Agricultural Chemical Usage. 2003. Nursery and Floriculture Sump1ary. 

### 6USDA, 2006-2010. NASS Crop Reporting Districts. Online: http://www.ers.usda.gov/briefing/anns/resourceregions/resourceregions.htm#nass
. USDA. 2007. Agricultural Chemical Usage. 2006. Nursery and Floriculture Summary. USDA, 2007. Census ofAgriculture. Online: http://www.agcensus.usda.govlPublications/2007/index.asp
. USEPA. 1996. R.E.D. Facts. Norflurazon. http://www.epa.gOY/oppsrrd1 /REDs/factsheets/0229fact.pdf
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