Focus Meeting for Norflurazon:Registration Review andEndangered SpeciesApril 11 20132Overview of Meeting Topics●Review of Use / Usage of Norflurazon-Potential for pre-assessment label clarifications●Ecological Risk Assessment Considerations-Geospatial analysis-Exposure refinements-Ecotoxicological refinementsNorflurazon Use4General Information: Overview●First Registered in the U.S. in 1974●Currently approved for controlling weeds in:-Aerial or ground applications-cotton, peanut, soybean, alfalfa-Ground applications only-almond, pecan, filbert, walnut-citrus, apple, apricot, avocado, cherry, nectarine, peach, pear, plum, prune-blackberry, raspberry, blueberry, cranberry, grape, hops, asparagus-non-agricultural farmstead areas (other non-crop uses such as field grown nursery andrights-of-way were cancelled in February 2013 by NuFarm/Riverdale)-no residential uses●Used to control certain annual broadleaf weeds, grasses and sedges and suppressionof certain perennial weeds●Preplant Incorporated (PPI) and Preemergence (Pre) / No Postemergence Activity●Section 24(C) for Solicam® DF in ArizonaAllows use via chemigation on alfalfa in LaPaz, Maricopa, Graham,Mojave, Pinal, Cochise counties5TechnicalEPA Reg.No.Registrant Active IngredientsNorflurazon Technical 100-839Syngenta Crop Protection,LLCNorflurazonEnd Use ProductsSolicam®(WDG)100-849Syngenta Crop Protection,LLCNorflurazonEvital® 5G (Granular) 5481-506AmVac Ag(Cranberry use Only)NorflurazonRecent Norflurazon Product Registration Cancellation :- Predict® : Riverdale Product, EPA Reg. No. 228 – 399(Federal Register vol. 78, No. 25, Feb. 6, 2013)Cancellation Request Pending (Per Syngenta Letter to EPA February 6, 2013)- Zorial® Rapid 80 : Syngenta Crop Protection, LLC, EPA Reg. No. 100-848Registered Products6General Information: Overview●Mechanism of Action: Inhibitor of phytoene desaturase (PDS), an enzymein the pathway for carotenoid production●Bleaching symptoms●Uptake of norflurazon is solely through the root system●Weed Resistance to this mode of action has only been documented in oneweedy species in the United States:-Hydrillaresistant to fluridone in aquatic systems (International Surveyof Resistant Weeds: weedscience.com), but norflurazon has no aquaticuses●Only herbicide with this mechanism of action in tree crops●Provides a tool for a herbicide resistance management program7Norflurazon Maximum Rates and Application MethodsUseMax. Single Appl.Broadcast Ratelb. product/acre(lb. a.i./acre)Max. Annual Appl.Broadcast Ratelb product/acre(lb a.i./acre)Peanut 1.8(1.4)1.8(1.4)Alfalfa, Cotton and Soybean 2.5(2.0)2.5(2.0)Almond, Pecan, Filbert, Walnut,Apple, Apricot, Avocado, Cherry, Nectarine, Peach,Pear, Plum, Prune, GrapeBlackberry, Raspberry, Blueberry, Hops and Asparagus5(3.9)5(3.9)Citrus (broadcast, band, ring drench, chemigation) 5.0 [10.0*](3.9)10.0(7.9)Cranberry (AmVac, 5GR) 160(8.0)160(8.0)Non-Agricultural Farmstead Areas5(3.9)5(3.9)* Newly planted non-bearing treesas a ring drench, FL only.8Norflurazon – Use for Newly Planted Non-Bearing Citrusin FloridaTreated Citrus trees with SolicamRings 3, 4 or 5 ft. diameterExample: mix 2.6 ounces Solicam in 500 gal. waterApply 5 gallons per tree in a 3-footdiameter circle around the tree.9Label Considerations for Risk AssessmentUse Restrictions (Example)●Crop use rates and number of applications vary greatly depending on geography, soiltype, organic matterRegionSoil TextureBroadcastRate(lb. Product/Treated acre)(lb. a.i./A)Other RestrictionsCottonSolicam DF can beused for weed controlin all cotton producingstates except CAclay loam, silty clay loam, siltyclay, clay2.5(2.0)single or split applicationloam, silt loam, silt, sandy clayloam, sandy clay and CoastalPlains Soils (SE US)0.95 – 1.9(0.75 – 1.5)Do not use rates higherthan 1.25 lbs. product PPIon coarse-textured CoastalPlains soilssand, loamy sand, sandy loam 0.625 – 1.25(0.50 - 0.98)Special directions for TX (Westof I-35), Southwest OK and NM0.60 – 1.0(0.47 – 0..79)In AZ, apply Solicam DFpreplant incorporated only0.65 – 1.25(0.51 – 0.98)10Label Considerations for Risk AssessmentDrift Management●Ground Application (min. 10 gpa)-Intend to add spray drift reductionmeasures for ground applications-Boom must not be higher than 20” above canopy-Use nozzles that product coarse spraydroplets and provide uniform coverage-Wind speed and direction requirements●Aerial Application (min. 5 gpa)-Use a drift control agent such as Nalco-Trol®-Outermost nozzles should not exceed3⁄4 of the wingspan or rotor-Apply large droplets-High flow rate nozzles-Spray released parallel to airflow-Narrow spray angle nozzles, low-drift nozzles-Apply no higher than10 ft. above the canopy-Adjust swath for crosswind-Avoid application if wind is < 3mph,minimal drift when wind is 3-10mph-In low humidity, increase droplet size to compensate for evaporation-Do not apply during temperature inversion-Only apply when the potential to drift to adjacent sensitive areas is minimal (when wind isblowing away from the sensitive area)11Potential Early Risk ReductionMeasures•Remove all non-agricultural farmstead uses from the label•Clarify DFU’s for ring drench applications to newly-plantednonbearing citrus in Florida•Label clarification for ground applications to minimizespray drift potential•Improve application directions in regard to wind speed foraerial applicationsApplication of Geospatial Analysis& RefinementGeographic Scope of Potential Norflurazon Uses – CropCounties●Major uses based on recent survey data are citrus, apples,almond* The maps show citrus, apple, and almond production counties reported in the 2007Census of Agriculture.14Geographic Scope of Norflurazon Uses –Sources●GfK Kynetec use survey data provides annual pesticide product use datasets atCrop Reporting District (CRD) level●California Pesticide Use Reporting (PUR) Data●Confidential marketing sales data can be shared under CBI●Information from growers and other experts15Norflurazon Use Pattern in CA:Total Annual Use(2001 to 2010)Use (Lb A.I.)Use (Lb A.I.)16Considering Geographically Specific Label Uses(CA example)Use Use in CA EFED Crop GroupMax. Annual Appl. Rate(lb a.i./ acre)NoteCitrus Y Orchards and grapes 3.9Citrus N Orchards and grapes 7.9Irrigated Citrus in FL and TX onlyApples Y Orchards and grapes 3.9Avocado Y Orchards and grapes 3.9 depends on soil textureFilbert Y Orchards and grapes 3.9 depends on soil textureNectarine Y Orchards and grapes 3.9 depends on soil texturePeach Y Orchards and grapes 3.9 depends on soil texturePecan Y Orchards and grapes 3.9 depends on soil textureApricot Y Orchards and grapes 3.9 depends on soil texturePear Y Orchards and grapes 3.9 depends on soil texturePrune Y Orchards and grapes 3.9 depends on soil textureWalnut Y Orchards and grapes 3.9 depends on soil textureAlmond Y Orchards and grapes 3.9 depends on soil textureCherry Y Orchards and grapes 3.9 depends on soil textureGrape Y Orchards and grapes 3.9 depends on soil textureBlueberry Y Vegetables and ground fruit 3.9 depends on soil textureBlackberry Y Vegetables and ground fruit 3.9 depends on soil textureRaspberry Y Vegetables and ground fruit 3.9 depends on soil textureAsparagus Y Vegetables and ground fruit 3.9 depends on soil textureHop Y Other crops 3.9 depends on soil textureCranberry N Vegetables and ground fruit 8.0 depends on soil textureCotton NCotton2.0BroadcastSoybean NCorn/soybeans2.0BroadcastAlfalfa Y Hay/forage/silage 2.0BroadcastPeanuts N Other row crops 1.4BroadcastNon-Ag uses Y No Ag 3.9 depends on soil texture19Geospatial Data (Species)•Species Information available at National LevelFederally Listed Species Information: U.S. Fish and Wildlife Service Threatened and EndangeredSpecies System (TESS, accessible at URL:http://ecos.fws.gov/tess_public/)Threatened & Endangered SpeciesCritical Habitats:U.S. FWS Critical Habitat Portal [URL:http://criticalhabitat.fws.gov].Additional spatial data digitized by Syngenta GIS Lab•Work products of FIFRA Endangered SpeciesTask Force (FESTF)Information Management System (IMS): TheIMS system contains the county-level species dataprovided from US EPA/US FWS and crop datafrom the USDA Census of Agriculture &Biological information.Multi-Jurisdictional Database (MJD):TheFESTF MJD provides an extensive database thatcontains location-specific information provided byNatureServe, along with its member NaturalHeritage Programs and Conservation Data Centers.Proximity Database: The access database includesproximity distance calculation using nature servelocation data and 2006 NLCD.An Example of Geospatial Data MatrixPesticide Use/Crop AreaHydrologyLand useSpeciesLocalStatesRegionalNational2006 NLCDHighResolutionElevationState UseReportsNS-MJDNS-IMSGAP Land CoverRecovery PlanNOAA RegionalofficeFWS RegionalofficeFWS CH portalNHD PlusCAL WaterCAL FishAg Census dataNASS CDLCNDDB (CA)NWI DataState landcover dataOther SpatialDataNAWQA/NWIS/STORETMonitoring DataSatellite/AerialImagesSteamnet.orgGfK SurveyState or research water qualitymonitoring programBird MigrationMonitoring dataPURDatabaseData LayersScale•Standardizing/updating best available spatial data matrix is necessary to ensure a use of“the best scientific andcommercial data available”.FWRI (FL)LabelBiologicalDataElevation(NED)23Quantitative Image Analysis Approachto Monitor Vegetation Changes in Riparian Zone•Long-term free satelliteimages collected fromhistorical product uselocations.•Using Vegetation Index(indicator of vegetationhealth/biomass growth),proved no changes invegetation stability withinriparian zone near ourproduct use areas.Examples of exposure refinements25Aquatic Exposure●Potential refinement to the standard EPA PRZM/EXAMS modeling (static farmpond):-Selection of a more appropriate SAMSON weather station.-Use of more representative weather data.-Selection of a crop/use scenario that is more appropriate for the norflurazon usebeing modeled.-Identification of a soil that is more representative of the norflurazon use patternwithin habitat of concern.●The level of refinement performed will vary over the different uses being assessed.Some uses may require no refinement, while some may require that all elementsabove be considered.●Simulated application dates are based on historical data when available (e.g. PURor supplementary information) to describe the likely application dates.●Simulation using flowing water body when applicable.26Example Refinement of Standard Scenario forNorflurazon use on Almonds in CA●EPA standard scenario for almonds (CAalmond_WirrigSTD):-Weather station: Sacramento (1961 – 1990)-Representative location: San Joaquin County-Soil: manteca fine sandy loam, hydrologic group C-Application rate: 5 lb/acre (product)3.93 lb/acre (ai)●Refinements applied:-Weather station: highest concentration of potential almond use sites withinCRLF habitat occurs in northern San Benito County and Southern Santa CruzCounty.-Application rate: norflurazon use on almonds requires application ratesdependent upon soil texture.-Runoff potential: curve numbers for the almond scenario were modified tomore accurately reflect the vegetation characteristics of the orchard.27Example Location of Standard and Refined WeatherStations Relative to Almonds in CRLF Habitat●The Sacramento weather station is closeto almond growing areas, however, theSalinas weather station is closest to theconcentration of almond growing areaswithin CRLF habitat.28Example Refinement of Standard Scenario for Norflurazon use onAlmonds in CA, Results●Refinement of the weather station to one more representative of conditionsin CRLF habitat resulted in a modest(~4 ug/L) reduction in the peak EEC.●Using the correct application rate for the soil type, had a significant impacton the peak EEC, lowering it further by ~ 50%.●The use of more appropriate CN values for typical orchard agronomicpractices resulted in additional ~25% reduction in the peak EEC.ScenarioAppRate(lb ai/ac) Weather CurveNumbers90th%‐ilePeakEEC(ug/L)CAalmond_WirrigSTD 3.93 Sacramento(EPA) Standard 30.4CAalmond_WirrigSTD 3.93 Salinas,1981‐2010 Standard 26.3CAalmond_WirrigSTD 1.96 Salinas,1981‐2010 Standard 13.2CAalmond_WirrigSTD 1.96 Salinas,1981‐2010 Adjusted 9.929A Probabilistic Static Pond Modeling Approach●The EPA standard farm pond scenarios are based on a hypothetical pond and asingle “representative” soil. The soil may be more associated with the crop beingmodeled than the geographic location it is intended to represent.●Alternative approach:-Identifies a population of representative ponds within a geographic extent ofinterest-Links local weather conditions with each pond-Characterizes actual crop potential use site extent (PCA) for each pond-Characterizes actual soil conditions co-occurring with use sites around eachpond●PRZM/EXAMS simulations are run for each pond-Standard farm pond characteristics are unaltered-Weather, soils, crop uses, and PCA vary for each pond●Ponds can be ranked according to EEC and overall “risk” assessed.30Ponds in CRLF Habitat (Example from PrometrynCRLF Assessment)●Approximately 5,000 small ponds are found within CRLF habitat.●A relatively small fraction of thoseare within close proximity to croppedareas and potential pesticide use sites.31Flowing Water BodyHydrologic flow should be incorporated in modeling exposure concentrations inflowing water bodies.0.00.20.40.60.81.0012345678

Relative concentration (C/Cmax)YearPRZM/EXAMS predicted normalizedconcentration using low flow andstatic versions of EPA farm pond compared with observed residuesFlowing farm pondNo flow farm pondObserved residuesFlowing Water Body (Example from PrometrynCRLF Assessment)Inclusion of physically based watershed scale model such as SWAT. PrometrynCRLF modeling indicated highest peak EEC of 63.2 μg/L (static), 8.1 μg/L(flowing, SWAT) and 3.1 μg/L (monitoring data).Norflurazon Surface Water Monitoring Data•An extensive database of environmental monitoring results was compiledfrom nine federal, state and other monitoring programs.•25,998 surface water samples collected between August 1983 and February2012SourceSampling Duration/Number of samples% Detection(# of detect/# of total samples)MaximumConcentration in μg/L(State of sample location)95thpercentileConcentration(μg/L)USGS NAWQA18 years,8052 samples7.5%(600/8052)7.3 (MS)0.895 years,557 samples51%(284/557)6.1 (MS)1.06USGS NWIS29 years,11650 samples7.0%(812/11650)96 (MS) 1.244 years,628 samples54%(339/628)7.38 (MS) 1.93EPA STORET9 years,588 samples22.3%(131/588)87 (FL) 1.5CDPR17 years,1199 samples11.8%(141/1199)1.49 0.648CEDEN3 months,111 samples6.3 %(7/111)0.256 0.256CILRP5 years,224 samples22.8%(51/224)1.4 1.34OR DEQ10 years,1329 samples3.4%(45/1329)0.489 0.3251 year,1 sample100%(1/1)0.021 0.021WA EIM19 years,2845 samples8.5%(242/2845)9.50.37SFWMD(Schuler and Rand,2008)17 years2063 samplesna 3.9 naWater Quality Monitoring Data: Basic Statistics* Bold values for the monitoring data statistics for demethyl-norflurazon (metabolite)35AgencyNumber ofsamples(sites)Sites with >100samplesSites with >25 samplesFrequency descriptionUSGS NAWQA380 (33) 0 4Few days apart, weekly, bi-weekly, monthly -frequency is dependenton the site locationUSGS NWIS550 (68) 0 6Dependent on site location, ranges from daily,weekly, bi-weekly, monthly, several monthsand yearlyEPA STORETNone NA NAIrregular, ranges from 1 per site to once permonth for a few monthsCA DPR1199 (96) 2 9Ranges from 2 days, weekly, monthly orirregular spaced samplingCA CEDEN111 (29) 0 0Ranges from 2 weeks apart to monthly or 1 toseveral times per yearCA ILRP224 (22) 0 0Ranges from 2 weeks apart to monthly or 1 toseveral times per yearWater Quality Monitoring Data in CA:Sampling FrequencySurface Water Monitoring Data in CaliforniaNAWQAMax 0.648 μg/L (MS), 95thpercentile 0.18 μg/LCRLF species habitatsboundaries:No samples and detectsCA DPRMax 1.49 μg/L, 95thpercentile 0.648 μg/LCRLF boundaries:3 sites, 17 samplesNo detectsNWISMax 0.65 μg/L (MS), 95thpercentile 0.18 μg/LCRLF species habitatsboundaries:4 sites, 4 samples,no detectsCEDENMax 0.256 μg/L , 95thpercentile 0.256 μg/LCRLF species habitatsboundaries:No samples and detectsEPA STORET9 years, 0 sites with > 100samplesNo samples in CaliforniaCILRPMax 1.4 μg/L, 95thpercentile1.34 μg/LCRLF species habitatsboundaries:No samples and detects37Example Terrestrial Plant Exposure: Runoff RefinementUsing PRZM Runoff FluxInput Parameter Value (lb/A)Application Rate 2Runoff Fraction0.02Drift Fraction0.01Input parameters for TerrPlant used to derive EECsEEC = TerrPlant Runoff Fractions + TerrPlant Drift FractionRefined EEC = PRZM Runoff Fractions + TerrPlant Drift FractionEEC = 0.02 (2 lb/A) + 0.01 (2 lb/A)EEC = 0.04 lb/A + 0.02 lb/AEEC = 0.06 lb/AInput Parameter Value (lb/A)Application Rate 2Runoff FractionOutput fromPRZMScenarioDrift Fraction0.01EEC = 0.0014 lb/A + 0.01 (2 lb/A)EEC = 0.0014 lb/A + 0.02 lb/AEEC = 0.0214 lb/AInput parameters for TerrPlant and output fromPRZM runoff used to derive EECsHypothetical scenarioEcotoxicological Refinements390.00.20.40.60.81.01 10 100 1000 10000

Proportion of Taxa AffectedConcentration(μg/L)Effects: Species Sensitivity Distributions (SSD)SSDs are useful for assessingeffects at the community-level.Functional redundancy isprevalent in many ecosystemsand therefore the reduction orloss of a species is unlikely toalter ecosystem function.Structural shifts≠Functionalchange.Examples of functional redundancySlight structural shifts in aquatic plant communities are unlikely to alter the overallprimary productivity and shelter availability in ecosystems.Similarly, in complex freshwater food webs, the prolonged existence of generalistpredators is unlikely affected by reductions in select prey species.Norflurazon SSD for aquatic plants40Effects: Appropriate HCxvalue for SSDLog Concentration

% of Taxa Affected0100908070605040302010Log Concentration

% of Taxa Affected0100908070605040302010Mode of action (Norflurazon)Non specific / narcosisInvertebrates and VertebratesPlantsEffect endpoints used for SSDLethalityMode of action (Norflurazon)Inhibits carotenoid biosynthesis byinhibiting phytoene desaturase.Effect endpoints used for SSDSublethal, growthRecovery following exposureNot applicable.Recovery following exposureEffects are reversible (Wilkinson 1985)HC5HC2041Effects: Probabilistic and statistical techniquesIncorporation of probabilistic statistical techniques for ecological risk assessment.42Effects: Aquatic Plant Endpoints for SSDsErickson (2010) details issues withinterpreting and applying plant toxicitytest results inProposed Methodology forSpecifying Atrazine Levels of Concern forProtection of Plant Communities inFreshwater Ecosystems.ECs are affected by:1) Test duration2) Observation interval3) Endpoint-absolute biomass (AB)- growth- specific growth rate (SGR)Absolute biomass may be misleading.“When control growth is just a doubling of biomassover the duration of the test, an EC50for absolutebiomass actually represents no growth.”Example: This illustration shows EC50values derived from SGR versus ABendpoints for aquatic plant exposed tonorflurazon over time. It demonstrateswhy SGR may be more useful for SSDs.050100150200250Days2 4 6 8 10 12 14050100150200250Vascular plantNon-vascular plant

Absolute Growth EC 50 (μg/L) Specific Growth Rate EC 50 (μg/L)43Effects: Terrestrial Plant SSDRyegrassCornCucumberMustardOatsCabbageOnionRadishSorghumSoybeanTomatoLettuceCommon test speciesUsing data from laboratorytoxicity tests with cropspecies as a surrogate forassessing risk to terrestrialplant communities is likelyhighly conservative.To account for the complexity of plantcommunities in riparian habitats, theuse of non-crop toxicity data in SSDsshould be considered.44Duration of exposure (d)0 20 40 60 80 100Basing EECs on study durationSelecting the most appropriate exposure duration for evaluating risk.ACUTECHRONICACUTECHRONIC21-d EEC60-d EECELSCHRONICSimilar considerationsfor terrestrial plant testsACUTE/CHRONICPeak EEC45Risk Quotient > Endangered Species Level of Concern (Acute = 0.1 / Chronic = 1)Effects: Risk Quotients Derived from T-REX v.1.5The user manual for T-REX v.1.5 states:“The risk assessment includes numerous calculations of dietary exposure for multiple weightclasses of animals. However, there are energeticconsiderations which suggest that some weightclass/food item combinations are not likely to occur naturally. For example, there are not likelyto be many 15 g mammals or 20 g birds that exclusively feed on vegetation. The risk assessor isurged to consult such texts as the Wildlife Exposure Factors Handbook (USEPA 1993), whichwill provide more comprehensive approaches for considering energy requirements and energyavailability to estimate dietary exposure.”Will all or only environmentally relevant weight class/food item comparisons inT-REX v.1.5. be considered for future risk assessments?Example: Output from T-REX v.1.5 based on hypothetical mammalian toxicity endpoints and pesticide usepattern.15 gramsAcute ChronicShort Grass 0.26 2.45Tall Grass 0.12 1.12Broadleaf plants 0.15 1.38Fruits/pods 0.02 0.15Arthropods 0.10 0.96Seeds 0.00 0.03Dose-based RQs(Dose-based EEC/LD50 orSmall mammal46Discussion / Next Steps●How to incorporate use clarifications / changes prior torisk assessments?●Refinements for risk assessments – process for proposingchanges to inputs for risk assessments?●Future timing of assessments /meetings / discussions fornorflurazon?