UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460



### SEP 22 2011

MEMORANDUM OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

SUBJECT: BEAD Chemical Profile for Registration Review: Pyrethrins (PC Code 069001)

FROM:

THRU:

TO: Nikhil Mallampalli, Entomologist Biological Analysis Branch

Jihad Alsadek, Economist
Science Information and Analysis Branch

Elizabeth Hill, Economist

Economic Analysis Branch Biological and Economic An }!l is**Div on**  (7503P)

Arnet Jones, Chief

# ~~ Biological Analysis Branch 

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Diann Sims, Chief

# I..f)~ Science Information and Analysis Branch

# ~ Timothy Kiely, Chief**~** Economic Analysis Branch Biological and Economic

# Anal**iviSiOn** (7503

Joel Wolf

Chemical Review Manager

Risk Management and Implementation Branch 2

Pesticide Reevaluation Division (7508P)

BEAD Product Review Panel date: August 24, 2011

INTRODUCTION 

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The purpose of this document is to convey usage information and a broad overview of the pest management roles of pesticides that are beginning to undergo registration review. The anticipated audience consists of the team of EP A staff currently evaluating the registration status

Page 

### 1 of7of pyrethrins, and eventually the general pub lic. This document builds upon the data already provided in the “Usage and Label Use Data Pack ages” that are also provided to Registration Review teams by BEAD. The document is based on information and data available to BEAD as of May 2011.

Pyrethrins were first registered in the United States for use as insecticides in the 1950s. A Reregistration Eligibility Decision (RED) was i ssued for this “active ingredient” (actually a group of very similar chemicals) in 2006 (see http://www.epa.gov/oppsrrd1/reregi stration/REDs/pyrethrins_red.pdf for details). As was done in the RED, the term “pyrethrins” in this paper re fers to formulations containing any or all six isomers found in pyrethrum, extracts which are de rived from the dried and ground flowers of the pyrethrum plant, Chrysanthemum cinerariaefolium

.

The Insecticide Resistance Action Committee (IRAC), comprised of technical personnel from various large agrochemical and public health compan ies, classifies pyrethrin s as a member of the Mode of Action Group 3 (subgroup 3A). This group of insecticides acts as sodium channel modulators, thus causing disrupti on of nerve impulses in the ta rget insects. All pyrethroids “initially stimulate nerve to produce repetitive discharges and subseque ntly cause paralysis” (Narahashi, 1976).

Pyrethrins target a wide range of insects in ma ny agricultural crop systems, such as lepidopterous caterpillars, leafhoppers, aphids, beetles, and thrips (FAO 1975), and is also used against a variety of urban insect pests su ch as cockroaches and ants. Li ke other compounds derived from the chemical structure of pyrethrum, it is most to xic to the target pest on contact, and has a quick “knockdown” effect (Doull 1976). Some manufacture rs formulate pyrethri ns with a synergist compound (usually piperonyl butoxide, also known as PBO, or MGK-264), as well as with other older pyrethroids such as tetramethrin, to exte nd its active life and increase its toxic effect on target insects (Jones 1998). Pyreth rum (as mixture of pyrethrins isom ers) is also available and (if formulated without synergists) are approved fo r use in U.S. organi c agriculture (Cornell University 2005; see also www.omri.org ).

USE SITES

Agricultural Use Sites

Pyrethrins are registered for hundreds of agri cultural uses, including most fruit, nut, and vegetable crops, as well as most major acreage cr ops such as corn, soybean, wheat, etc. Given
the insecticide’s short re sidual activity and tendency to degrade in sunlight after application, it is likely that use on crops grown outdoors is limited to spot treatment intended to clean up small infestations or knock pests off pl ants shortly before harvest. At least one reference located by BEAD specifically mentions this type of us e (FAO 1975). There are also indoor (greenhouse) uses listed for a variety of crops (e.g., tomato es, ornamental plants, etc.). For these crops, pyrethrins may be a more frequent choice of pro ducers, since residual activity may be longer due to lower exposure to sunlight.

Page 2 of 7Non-Agricultural Use Sites

Sites listed in the LUIS report include wood pr oducts (e.g., beams, decks, and pilings), woodland areas, wood surfaces, and zoos (enclosures and out door perimeter areas). Woolen fabrics are also listed; it is likely these are impregnated and in tended to protect wear ers from biting flies and
ticks.

Usage data (see below) indicate th at other non-agricultura l use sites where pyrethrins are used to any degree include residential and commercia l buildings, food handling establishments, institutional turf, nursery/greenhous e, and for mosquito abatement.

COMMON FORMULATIONS A ND APPLICATION METHODS

Pyrethrins are formulated as granular, emulsifi able concentrate, soluti on ready-to-use and as pressurized gas and liquid. It is unclear which of these is predominantly used in agricultural settings. BEAD speculates that for non-agricultural settings, ready-to use and liquid formulations are more frequently used. For agricultural uses , any of the formulations may be used; BEAD has no information on extent of use of each type.

Application methods in agricultu ral and non-agricultural uses (bas ed on the RED) are diverse, and include: aerosol can, mist blower, metered release devices, total release aerosol, fixed wing aircraft, helicopter, truck-mounted ultra low volume (ULV) equipmen t, cold aerosol generator, hand held sprayers (high or low pressure ha ndwands), thermal/cold/ULV fogging equipment, conventional dusting equipment (e.g., power duster, bulb duster, shaker can), outdoor misting systems, and irrigation systems.

Of these, power dusting was banned by the RED due to the Agency’s inability assess risk scenarios; all other application methods are apparently still on the labels. However, due to human health risk concerns, several risk mitigation meas ures (e.g., limits on the number of applications per year or individual area tr eated) were imposed by the RED for three general application methods: broadcast dusts applied to carpets, i ndoor metered release devices, and outdoor residential misting systems.

As far as agricultural application methods, BE AD has no specific data on extent of use of different types. However, given the short residual activity, BEAD speculates that ground application using either trac tor drawn equipment or backpack sprayers are often used

USAGE

Usage in non-agricultural settings (lawn care, re sidential uses, public health pest control) is higher than use in agriculture as a whole. Details are provided below.

Page 3 of 7Agricultural use

Based on private market pesticide usage data from 1998-2010, the annual to tal agricultural usage averaged approximately 2,000 pounds active ingredie nt for 123,000 acres for an overall average of 0.02 lbs. a.i. application rate per acre. In co mparison to this rate, the average a.i. application rate for lettuce is 0.03 lbs. a.i. pe r acre, 0.05 lbs. a.i. for oranges, 0.02 lbs. a.i. for strawberries,
and 0.01 lbs. a.i. for winter wheat.

From 1998-2010, the largest markets in terms of total pounds of active ingredient applied are lettuce (17%), winter wheat (16%), oranges (9%), and strawberries (8%). The highest total area treated (TAT) are winter wheat (20%), and soybeans and lettuce (9% each).

On average, the states with the most agricu ltural usage in terms of pounds a.i. applied are California (52%), Oklahoma (16%), and Arizona (6%) (G fKynetic, 1998-2010).

Figure 1 provides usage trends, in terms of pound s applied, for pyrethrin’s largest agricultural markets. The use of pyrethrins on lettuce fluc tuated while was rising on both oranges and strawberries. The use of pyrethrins on winter wheat spiked in 2007 but th ere was little use in other years (1998-2010). Another option to show the use of pyrethrins across all crops is in Figure 2. Figure 2 shows the use of pyrethrin s to be fluctuating during the period 1998-2010, and is highest in 2007.

Figure 1 . Usage data for pyrethrins in the largest agricultural markets.

Source : Proprietary Data, 1998-2010

Note : “Other crops” depicted above includ e: alfalfa, almonds, apples, artichoke, asparagus, beans, broccoli, cabbage, caneberries, cantaloupes, carrots, cauliflo wer, celery, cherries, corn, cotton, cu cumbers, dry beans, grapes, hazelnuts, lemons, lima beans, onions, oranges, peaches, pears, peas, pecans, peppers , pistachios, plums/prune, potatoes, pumpkin, sorghum, soybeans, spinach, squash, sugar beets, sugarcane, sunflowers, sweet corn, tomatoes, walnuts, spring wheat, and watermelons.

Page 4 of 7Figure 2 . Usage data for pyrethrins across all crops .

Source : Proprietary Data, 1998-2010

Non-Agricultural use

The use of pyrethrins by consumers for indoor use appeared to be rising between 2003-2006 (52,000 lbs. a.i. in 2003 and 113,000 lbs. a.i. in 2006) ; see Table 1 below. There was little use in food handling establishments (FHEs) and on institutional tu rf, less than 500 lbs. a.i. each. The use of pyrethrins by lawn care operators (LCOs) was declining from 3,000 lbs. a.i. in 2002 to
less than 500 lbs. a.i. in 2006. The use for mo squito abatement was rising (2,000 lbs. a.i. in 2003 and 12,000 lbs. a.i. in 2006). The use of pyr ethrins for nurseries and greenhouses was less than 500 lbs. a.i. in 2002, 2004, and 2006. Pest c ontrol operators used ab out 9,000 lbs. a.i. of pyrethrins in 2003.

Table 1. Non-Agricultural use of pyrethrins acro ss recent years in various site categories.

Site 2002(Lbs.) 2003(Lbs.) 2004(Lbs.) 2005(Lbs.) 2006(Lbs.) 2008(Lbs.)

Consumers/Indoors
- 52,000 113,000 Food Handling
Establishments (FHEs) - - - - - <500

Institutional Turf
- - - - <500
- Lawn Care Operators (LCOs) 3,000
- - - <500
-

Mosquito
Abatement - 2,000
- - 12,000
-

Nursery/Greenhouse <500 <500
- <500
- Pest Control Operators (PCOs) - 9,000
- - - -

Note: - indicates that data are not available.

Source : Kline and Company, Inc., 2002-2006.

Page 5 of 7BEAD cautions that since usage of pyrethrins as reported to the databa ses is low (and for nonagricultural uses, is limited to years prior to 2009), some usage may be under-represented and some usage trends may need refinement. BEAD hopes that the response from the stakeholder public to the questions posed in the “Data Needs” section (below) will help the Agency in more precisely assessing recent usage of these insecticides.

BIOLOGICAL ASPECTS RELEVANT TO PYRETHRINS

A search of the database on arthropods resistan t to pesticides (maintained online by Michigan State University and accessible at www.pesticider esistance.org) indicates that many insects have evolved resistance to pyrethrins (formulated with and without synergists) over the many years that the products have been in use. The list is diverse, covers both case s within and outside the U.S., and includes urban pests such as Germ an cockroaches and houseflies, as well as widespread agricultural and stored commodity pests such as the green peach aphid ( Myzus persicae ), Indian meal moth ( Plodia interpunctella ), and red flour beetle ( Tribolium castaneum ). BEAD’s initial assessment, based on a scan of the literature mentioned in the database and other internet accessible sources, is th at such resistance has not become consistently widespread in the U.S.; rather, it develops repeat edly in isolated instances.

Another interesting aspect of pyrethrins that may be acting to increase usage in some crops is that some formulations without synergists (e.g., ‘Pyganic”, which c ontains pyrethrum, an
unrefined combination of all six pyrethrins isomers) are on the lis t of Organic Materials Review Institute (OMRI) approved “organic” insecticides (see www.omri.org ). OMRI lists are often used by certifying agencies to validate organic produ cts (Cornell University 2005). Since chemical pest control options are limited for such producers, this product may be seeing increased usage in recent years as the demand for some organic foods has increased in the general public. However, this is merely speculation on BEAD’s part at this poi nt, as no specific data fo r this type of use are immediately available.

HISTORY OF BEAD ASSESSMENTS FOR PYRETHRINS

To date, BEAD has not conducted any assessments for pyrethrins. However, two Section 18 emergency exemption requests are recorded in EPA’s Section 18 Action Database (EPA, 2011).
Please refer to Attachment 1 for a review of these requests.

DATA NEEDS RELEVANT TO BEAD’S FU TURE WORK ON PYRETHRINS

Obtaining additional information on the following items would improve future BEAD assessments of the importance of pyrethrins and may be required as part of the registration review of this pesticide.

1) Usage data such as pounds AI applied, area tr eated, typical use rates, and typical number of applications on the following sites: i ndustrial sites, livest ock, milk, and meat.

2) Importance to users in organic farming (e .g., frequency of use per season, application rates and methods in specific organic crops).

Page 6 of 7Page 7 of 7 3) Usage data for the agricultural crops that ar e not covered in the us age section of this
document.

4) Usage data (pounds AI applied and area treate d) for indoor/outdoor consumer use, use in food handling establishments /food processing establishments, and use in and around
commercial and institutional facilities.

REFERENCES

Cornell University. 2005. Resource Guide for Or ganic Insect and Diseas e Management
Available at: http://web.pppmb.cals.cornel l.edu/resourceguide/index.php [Accessed August 2011].

FAO. 1975. Data Sheets on Pesticides, No.11: Pyrethrins. Available at: http://www.inchem.org/documents/pds/pds/pest11_e.htm [Accessed August 2011].

Doull, J. 1976. The Treatment of Insecticid e Poisoning. Ch. 16 in: C.F. Wilkinson (ed.), Insecticide Biochemistry and Physio logy. 753 pp. Plenum Press, New York.

Environmental Protection Agency (EPA). 2011. Section 18 Action Database. Located at: http://cfpub1.epa.gov/oppr ef/section18/s earch.cfm

Jones, D.G (ed.). 1998. Piperonyl Butoxide: The In secticide Synergist. 323 pp. Academic Press, San Diego, CA.

Narahashi, T. 1976. Effects of Insecticides on Nervous Conduction and Synaptic Transmission. Ch. 9 in: C.F. Wilkinson (ed.) , Insecticide Biochemistry and Physiology. 753 pp. Plenum Press, New York.

GfK Kynetec. (1998-2008). EP A Proprietary Data.

ATTACHMENT 1

Chemical Site Pest Applicant Received

Date Date
Response

Date Status

PYRETHRINS AIRCRAFT
SURFACES,

CONTAINERS BROWN

RECLUSE

SPIDER New York 6/24/2004 6/24/2004 CRISIS

APPROVED

PYRETHRINS AQUATIC SITES RED SWAMP

CRAYFISH WISCONSIN 8/6/2010 8/25/2010 CRISIS

APPROVED