UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D

.C

. 20460 

## SEP 20 2011

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: BEAD Chemical Profile for Registration Review: Tetramethrin (PC Code: 069003) FROM:

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TO: Nikhil Mallampalli, Entomologist Biological Analysis Branch Rafael A. Prieto, Environmental Protection

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# J A·**.** Science Information and Analysis Branch 

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# //'fyv . Elizabeth Hill, Economist Economic Analysis Branch Biological and Economic Analysis Division (7503P Arnet Jones, Chief /),../ } Biological Analysis

## Bran**cl ~**  Diann Sims, Chief

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. Science Information and Analysis Branch Timothy Kiely, Chief 

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Economic Analysis Branch

## ~ Biological and Economic Analysis ivision (7503P) Monica Wait, Chemical Review Manager Risk Management and ImplementationBranch 3 Pesticide Re-evaluation Division (7508P)

BEAD Product Review Panel date: August 24, 2011 INTRODUCTION The purpose ofthis document is to convey usage information 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 oftetramethrin, and eventually the general public. This document builds upon the data already Page 1 of4provided inthe "Usage and Label Use Data Packages" that are also providedto Registration Reviewteams by BEAD. However, for tetramethrin the usage and label use package will be provided at a later stage ofregistration reviewbecause product reregistration is ongoing, and all product labels are expected to be revised as a result ofthatprocess. The document is based on information and data available to BEAD as ofAugust 2011. Tetramethrin was the subject ofan Agency Reregistration Eligibility Decision (RED) in 2008, and the RED was amended in April 2010 (go to http://www.epa.gov/oppsrrd1IREDs/tetramethrin-revised-red.pdffor the document). To quote the RED: "tetramethrin is part ofthe pyrethroid class ofpesticides and was first registered in 1968. It is a broad spectrum, non-systemic, synthetic pyrethroidused to control flying and crawling insects in a number ofcommercial, horticultural andresidential applications." The Insecticide Resistance Action Committee (IRAC), comprised oftechnical personnel from various large agrochemical andpublic health companies, classifies tetramethrin as a member of the Mode ofAction Group 3 (subgroup 3A). This group ofinsecticides acts as sodium channel modulators, thus causing disruption ofnerve impulses inthe target insects. All pyrethroids "initially stimulate nerve to produce repetitive discharges and subsequently cause paralysis" (Narahashi, 1976). Like other compounds derived from the chemical structure ofpyrethrum, it is mosttoxic to the targetpest on contact, and has a quick "knockdown" effect, which is the initial paralysis and quick intoxication caused bynerve stimulation (Doull 1976). Tetramethrin is sometimes formulated with a synergist compound, usually piperonyl butoxide (PBO) orMGK264, to extend its active life and increase its toxic effect ontarget insects (Jones 1998). It is also sometimes formulated withpyrethrins or synthetic pyrethroids for the same purpose. 

### USE SITES This information was summarizedwell in the amended RED and that list has not changed. To quote the relevant text from the amended RED document: "Commercial [uses] include space sprays, broadcast surface treatments, and crack and crevice treatments in a variety ofindustrial and institutional sites including: indoor non-food areas; animal premises (not used for human consumption); and outdoors as localized space and contact sprays on ornamental plants andperimeter treatments (sidewalks, entranceways, outside surfaces ofbuildings, etc.). Residential uses include: pest control inhomes as a space spray, general surface spray, spot and crack and crevice applications, on house plants, clothing and bedding, petpremises, and direct applications to pets. [In the residential use context] outdoors itis used as localized space and contact spray on ornamental plants and perimetertreatments (sidewalks, decks, patios, outside surfaces ofbuildings, etc.). Horticultural [uses] include foliar and fogger treatment onnon-foodplants. There are no registered food use applications for tetramethrin." 

### COMMON FORMULATIONS AND APPLICATION METHODS Page 2 of4Tetramethrinproducts are formulated as emulsifiable concentrates, pressurized gases and liquids, and ready-to-use solutions. These products are applied as a crack and crevice treatments, surface treatments, aerosols, fogs, and sprays. USAGE BEAD has very limitedusage data for tetramethrin. Tetramethrin is active againstmost insects upon contact; the labeled uses suggestthat urban and nuisance pests such as cockroaches, wasps, flies, and ants are frequent targets ofuse. In 2005, the most recent year for which BEAD has data, approximately 310,000 lb oftetramethrin was usedby consumers ofindoor residential treatments. Data for earlier ormore recent years were not available to EPA. Usage was not reported inthe available reports on food handling establishments; however, usage may be occurring belowthe reporting threshold. (Kline and Company 2005). BIOLOGICAL ASPECTS RELEVANT TO TETRAMETHRIN Tetramethrin is among the earliest synthetic pyrethroids developed (Casida 1980). While tetramethrin has better powers ofknockdown than other older pyrethroids such as pyrethrins or allethrin, it has only about "equal powers ofkilling" as these materials (Incho 1970). Like these older pyrethroids, tetramethrin is also susceptible to quick degradation in sunlight (Soderlund 2008). Given its short-lived residual activity, it is perhaps not surprising that usage of tetramethrin is currently low and apparently largely limited to indoor settings. Newer pyrethroids, such as deltamethrin, bifenthrin, and cyfluthrin have taken over agricultural markets once dominated by early pyrethroids, since the newer products are much less photo-labile (Casida 1980, Soderlund 2008). Due perhaps to its long history ofuse, resistance has been reported inthe scientific literature for a number ofinsects inthe U.S.A. and globally. For example, the Arthropod Pesticide Resistance Database maintained by Michigan State University (onthe web at http://www.pesticideresistance.orgQliststheGermancockroach.chickenmite, cottonbollworm, and common housefly as showing confirmedresistance both within the U.S. and in other countries. Itis not clear to BEAD exactly how quickly or widely resistance to tetramethrin,

, specifically, spreads in pests, or how persistent it is. However, resistance problems may also be a factor in the apparently low usage oftetramethrin that is suggested by the limited data BEAD has available. HISTORY OF BEAD ASSESSMENTS FORTETRAMETHRIN BEAD's Official Records indicate no formal assessments ontetramethrin were conducted. The EPA Section 18 Action Database also indicates that no Section 18 requests were made for the use ofthis chemical (EPA, 2011).

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### 3 of4DATANEEDS RELEVANT TO BEAD'S FUTURE WORK ON TETRAMETHRIN Obtaining additional information onthe following items would improve future BEAD assessments ofthe importance oftetramethrin and maybe required as part ofthe registration review ofthis pesticide. 1) Usage data (pounds AI applied and areatreated) for indoor/outdoor consumeruse, use in food handling establishments/food processing establishments, anduse in and around commercial and institutional facilities. 2) Usage data (pounds AI applied and area treated) for horticultural plant production. REFERENCES Casida. J. 1980. Pyrethrum Flowers and Pyrethroid Insecticides. Environmental Health Perspectives Vol. 34, pp. 189-202. Doull, J. 1976. The Treatment ofInsecticide Poisoning. Ch. 16 in: C.F. Wilkinson (ed.), Insecticide Biochemistry and Physiology. 753 pp. Plenum Press, New York. Environmental Protection Agency (EPA). 2011. Section 18 Action Database. Located at: http://cfpubl.epa.gov/oppref/section18/search.cfm Incho, H.H. 1970. New insecticide for aerosols. Soap & Chemical Specialties Vol. 46 (2): 37- 40. Jones, D.G (ed.). 1998. Piperonyl Butoxide: The Insecticide Synergist. 323 pp. Academic Press, SanDiego, CA. Narahashi, T. 1976. Effects ofInsecticides onNervous Conduction and Synaptic Transmission. Ch. 9 in: C.F. Wilkinson (ed.), Insecticide Biochemistry and Physiology. 753 pp. Plenum Press, New York. Soderlund, D. 2008. Pyrethroids, knockdownresistance and sodium channels. Pest Manag. Sci. 64: 610-616. Kline and Company, Inc. 2005.

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