UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

DEC S 02010

OFFICE OF

CHEMICAL SAFETY AND

POLlUTION PREVENTION

MEMORANDUM

SUBJECT: BEAD Chemical Profile for Registration Review: Piperonyl Butoxide (PC Code:

067501)

FROM : Nikhil Mallampalli, Entomologist

Biological Analysis Branch

Jihad Alsadek , Economist

Science Information & Analysis Branch

Biological and Economic Anal sis Division (7503P)

Stephen Smearman, Economist I. _.J

Economic Analysis Branch -f.JCRl -_

J"W If .tt4JLi

THRU: Arnet Jones, Chief

Biological Analysis Bran

Timothy Kiely, Chief

Economic Analysis Branch

Diann Sims, Chief

Science Inform ation & Analysis Brane

Biological and Economi c Analysis Division (7503P

T O: Jose Gayoso

Chemical Review Manager

Pesticide Reevaluation Division (7508P)

BEAD Product Review Panel date: September 15, 2010

Page I of6
Introduction

Piperonyl butoxide (PBO) is a chemical that is added in formulations of synthetic pyrethro ids

and organophosphates to increase their insecticidal activity. This effect is called synergism.

There is also evidence that the addition of PRO (either as part of a formulation or appl ied

separately) increases pyrethroid efficacy against insect populations showing resistance to this

class of insecticides (e.g., Bingham et al. 2007). A good overview ofthe history of PBO is

provided by Jones (1999) and paraphrased by the website "Friends of Pyrethrum" (see

http ://friendsofpyrethrum.co'.uklPBO-lntroduction.html).

This document follows a format recently developed by BEAD to convey usage information on

pesticides that are beginning to undergo registration review. The antici pated audience for this

paper consists of the team of EPA staff currently evaluating the registration status ofPBO, as

we ll as the general public. This document builds upon the data already provided in the "Usage

and Label Use Data Packages" that are also prov ided to Registration Review teams by BEAD.

COMMON FORMULAnONS AND APPLICAnON METHODS

PBO is usually formulated in mixtures with insecticides, primaril y synthetic pyrethroids. Thus, it

is avai lable in diverse forms, including aerosols, liquids, ready-to-use solutions, dusts, wettable

powders, microencapsulates, impregnated materials, pressurized gases, pressurized liquids,

press urized sprays, micro-emulsions, dilutable concentrates, shampoos, pour-ons (spot-on), and

water-based concentrates.

In agricultura l uses, common formulations used are likely to include liquid, wettable powder, and

microencapsulate (since these are formulations that are used for synthetic pyre throids). In nonagricultural settings (e.g ., residential and food -handling establishments), commonly used

formulations include ready-to-use solutions, liquids, and aerosols.

Application methods are also diverse. They include aerosol cans, mist blowers, metered aeroso l

units, aerial application, truck-mounted ultr a low volume (ULV) equipment, hand held sprayers,

thermal fogging equipment, conventional dusting equipment (e.g., shaker cans), and irrigation

systems. Ofthese, ae rial and ground equipment used for synthetic pyrethro ids are probably

common in agricultural use sites, while application methods such as hand held sprayers, shaker

cans, and ae roso l units are more typical in non- agricult ural sites.

USAGE

Agricultural Usage

Based on private market pesticide usage data from 1998-200 8, annual total agricultural usage

ave raged approximately 9,000 Ibs active ingredient (a.i.) for almost 60,000 acres of all crops

(GfK Kynetic, 1998-2008).

Page 2 aUl
During the same time period, 1998-2008, the largest markets in terms of total pounds of active

ingredientapplied were: winter wheat (39%), potatoes (13%), milo sorghum (8%), lettuce (6%),

alfalfa, strawberries, & lemons (5%, each), and sweet com (4%) (GtK Kynetcc, 1998-2008).

Figure 1.

II Straw berries

• terren e

[] Sweet Corn

• O!her

4' %

, % 13%

14%

Piperonyl.Butollide largest Crop Markets

r.:c_:::c-c,,-c.",=,,-.,.1

• sotetces

o Sorghum(MIo)

o l ettuce

• Alfalfa

s%

The states with the most agricultural usage in terms ofpounds a.i. applied include Oklahoma,

California, Wisconsin. Arkansas, Iowa, Alabama, and Texas (GfK Kynetec, 1998-2008).

Figure 2.

• OKLAH)fJA

• CAlFC>fNt\

cx:>NS

o ARKANSAS

U lWA

• ALABAM4.

• TEXAS

[] Other

40%

22%

,%

States Using Piperonyl·Butollide Most

Poundage

Non-Agricultural Usage

Kline data are limited, and date from 1999. They show that about 675 Ib a.i. of PBO were used

on institutional turf, and almost 50 pounds on nursery/greenhouse. BEAD found other

potentially outdated data (from 1997) in USDA's National Agricultural Statistics Service

(NASS) surveys. thatshow about 51 ,000 Ibs ofPBO were used on all livestock. and almost

19.000 pounds were used in miscellaneous general farm use, buildings and structures, roads, and

ditches. NASS data also show about 1,200 Ibs were used in 2000, 200 Ibs in 2003, and 700 Ibs

in 2006 on all nurseryand floriculture crops. NASS data on postharvest uses show that about 300

lbs of PBO were used on peanuts in 1999 and almost 3,000 Ibs in 2004-05 (NASS , 1999-2001,

2003, 2006).

Page 3 of6
USE TRENDS

There was no PBO use on alfalfa, except in 2003 (almost 4,500 Ibs a.i.), no use on lemons from

1998-03, almost 2,000 Ibs in 2004 and started to decline from then on, use on lettuce peaked in

2005 (almost 4,000 lbs a.i.) and went down to 34 1 1bs in 200 8. Usage on potatoes peaked in 2004

(almost 8,500 Ibs) and went down to zero in following years. Milo sorghum was treated only in

2000 (almost 8,000 Ibs); use on strawberries was relatively high in 2000 (almost 4,000 Ibs), and

almost went down to zero there after. Sweet com was treated with PSO in 2000 only (almost

4,000 lbs), and winter wheat was mainly treated in 2007 (almost 38,000 Ibs).

The following graphs provide usage trends for PBO, in terms of pounds applied, for the largest

agricultural markets.

Figure 3. Pounds of PBO Applied to Winter Wheat (1998-2008)

Winter Wheat

<i. 40,000

-e

•

c

,

0 0 Q,

,,'0 ",& ",,, ",d' ",'0 ",'0

,,, 'l) l' 'l) l' "c:;

Year

Source: GfK Kynetec, 1998-2008

Figure 4. Pounds of PBO Applied to Potatoes (1998-2008)

Potatoes

<i. 10.000

..,

•

c

,

0 0 Q,

,,'0 ",c:; c:;" ",d' ",<0 ",'0 ," l' l' 'l) l' "c:;

Year

Source: GfK Kynetec, 1998-2008

Page 4 of6
Figure 5. Pounds of PBO Applied to Sorghum (Milo) (1998-2008)

Sorghum(Milo)

... 10,000

-e

•

e

,

0 0 Q.

,,<fJ' ",<S' ",, <f>~ "' ",<!P

-c '" ,,'"

Year

'" '"

Source: GfK Kynctec, 1998·2008

Figure 6. Pounds of PBO Applied to Lettuce (1998-2008)

Le ttuce

-'

... 4.000

•

"

n e

,

0 0 Q.

,,<fJ'

, <f><S' <f>"''' <f> ",<!' ",<!P

'" '"

Year

Source: GtK Kynetec, 1998·2008

PBO usage trends (in both agricultural and non-agricultural sites) probably reflect those of

several synthetic pyreth roid s (e.g. , cyfluthrin, esfc nvalerate, etc.) it is formulated with. Synthetic

pyrethro ids in the cro ps menti oned above are typically used mo st often to control a variety of

caterpillars, aphids, beetles, and grasshoppers/crickets. While pyrethroids (like

organophosphates) are-toxic on contact as we ll as afte r ingestion, they are particularly valued by

growers and pest control operators for their rapid "knockdown" effect - a temporary paralysis

that literally causes target insects to fall offthe plant. This can be particularly useful if insects

need to be controlled as well as removed close to harvest.

Past BEAD assessments

There were no formal impact assessments done for the PBO Reregistration Eligibility Decision

(which was issued in 2006). There is one Section 18 review by BEAD for an emergency

exemption request by California to use a mixt ure of PBO and d-phenothrin to control mosquitoes

in almonds, pastures, rice, and tree nuts (Brassard. 2005 ).

Page 5 of6
DATA NEEDS RELEVANT TO BEAD's FUTURE WORK ON PDO

Obtaining additional information on the following items would impro ve BEAD' s assessment of

the importance of PBO as a pest management tool. This assessment is may be required as part of

the registration review of this pesticide.

1. For non-agricultural uses, information on target pests, efficacy of PBO and its technically

feasible alternatives (e.g., MGK-264), and treatment costs.

2. Confirmation of the major target pests for which PSO is used in agricultural production.

3. Recent resistance reports for PBO in populations of important target pests.

4. For agricultural uses, worker activities that occur in treated fields at the typical time of

PSO applications.

REFERENCES:

Bingham, G., R.V. Gunni ng, K. Gorman, L.M. Field, and G.D. Moores. 2007. Temporal

synergism by microencapsulation of piperonyl butoxide and u-cypermethrin overcomes

insecticide resistance in crop pests. Pest Management Sci. 63: 276-281.

Brassard, D. 2005. Piperonyl butoxide +d-phenothrin for mosquito control (W. Nile virus) in

almond, grass pastures, rice, and walnut (DP # 3194 10). Internal BEAD document

transmitted to OPP's Registration Division.

Jones, D.G (ed.). 1998 . Piperonyl Butoxide: The Insecticide Synergist. 323 pp. Academic Press,

San Diego, CA.

GtK Kynet ec. (1998-2008). EPA Proprietary Data.

NASS Agricultural Chemical Usage 1999 Livestock Summary. Available at:

www.nass. usda. gov/.

NASS Agricultural Chemical Usage 2000 Nursery and Floriculture Summary, 2002. Available

at: \'...ww.nass.usda.gov/.

NASS Agricultural Chemical Usage 2003 Nursery and Floriculture Summary, 2004. Available

at: \\'\'lw.nass.usda.gov /.

NASS Agricultural Chemical Usage 2006 Nursery and Floriculture Summary, 2007. Available

at: www.nass.usda.gov/.

NASS Agricultural Chemical Usage 2001 Postharvest Applications-Peanuts, Rice, and Sorghum.

Available at: \'...\\w .nass.usda.gov/.

NASS Agricultural Chemical Usage 2006 Postharvest Applications-Peanuts Summary. Available

at: w\\'w .nass.usda.gov/.

Page6 of6