UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

NOV 17 2014 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENT ION 

MEMORANDUM 

SUBJECT: 

FROM: 

THRU: 

BEAD Chemical Profile (BCP) for Registration Review: Spirodiclofen (PC Code: 

124871) 

Nikhil Mallampalli, Biologist 

Biological Analysis Branch 

Claire 

Science 

Pa

Information 

isley-Jones, 

and 

Biologist 

Analysis Branch ~ 

(} ~L {Y-' · 1 

Michelle Ranville, Economist f.\- V\A... ~ 

Economic Analysis Branch ':! V. 

Biological and Economic Anal sis Division (7503 

Arnet Jones, Chief 

Biological Analysis BrancH 

Diann Sims, Chief~ Science Information and Analysis Branch 

Timothy Kiely, Chief n101AAAJ~ , fo-r 7/mofhy J((~l~ Economic Analysis Branch 

Biological and Economic Analysis Division (7503P) 

TO: Julia Stokes, Chemical Review Manager 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel date: October 15,2014 

Page 1 of8 
SUMMARY 

· Spirodiclofen is a miticide (acaricide) currently undergoing registration review. Since it was first 

registered in 2005, it has not undergone such a review in the past. This pesticide is mite-specific 

and acts by interfering with growth regulation and lipid biosynthesis. It is currently registered for 

use in a variety of fruits and nuts, as well as hops and Christmas tree plantations. National level 

use of spirodiclofen increased steadily after registration, but this trend peaked in 2010. Available 

data indicate a noticeable decline in usage since then. The reasons for this decline are not fully 

clear but probably include factors such as the need to control mites along with other similar 

pests- such as whiteflies- against which spirodiclofen has little activity, and localized pest 

resistance. Crops that showed major use of spirodiclofen include citrus fruits, grapes, and 

almonds, all of which have various significant mite pests in most growing regions. Details of 

usage, the chemical's role in pest management, and current BEAD data needs relevant to 

registration review are presented below. 

INTRODUCTION 

The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an 

overview of the pest management roles and quantitative usage information for spirodiclofen 

(brand name Envidor®). This BCP includes summaries of previous BEAD products and 

available public and/or private use and usage data for spirodiclofen to describe the role of this 

chemical in pest management. Additional information on use is available in the spirodiclofen 

PRD Label Data Report. Information provided in this document may be used by stakeholders 

(e.g., users and registrants), OPP risk assessors and risk managers, and the general public during 

the Registration Review process of this pesticide. 

HISTORY OF BEAD ASSESSMENTS FOR SPIRODICLOFEN 

Spirodiclofen is relatively new to the U.S. market; it was first registered conditionally in 2005. A 

Screening Level Usage Analysis (SLUA) was prepared for this chemical for the first time in 

2014, which provides the average percent crop treated for agricultural crops between 2004 and 

2011. . 

A preliminary impact analysis for aldicarb in citrus crops, conducted by BEAD in 2006, noted 

that spirodiclofen is one of three effective alternatives for control of citrus rust mites in Florida 

(Kaul and Berwald 2006). 

USE SITES 

Agricultural Use Sites 

Spirodiclofen is registered for use on a number of agricultural crops including citrus, grapes, 

pome fruit, stone fruit, tree nuts, tropical fruits, berries, hops, and christmas tree plantations. 

Page 2 of8 
Non-Agricultural Use Sites 

Spirodiclofen is not registered for any non-agricultural uses. 

FORMULATIONS 

Spirodiclofen currently has only two active registrations: a technical chemical and a suspension 

concentrate. 

APPLICATION METHODS 

Spirodiclofen is applied once per crop season using ground equipment, including airblast. Aerial 

application is also allowed, but only for avocadoes and Christmas trees. Applications through 

any type of irrigation system or in any enclosed structure are prohibited. 

USAGE 

Agricultural Usage 

Based on private market usage data, use of spirodiclofen increased steadily from 2005 when 

the product was first registered, until2010 when usage peaked in terms of both total pounds 

a.i applied and total surveyed acres treated. Since 2010, usage has markedly decreased 

(Table 1) (Proprietary Data 2005-2012). 

150,000 

Total Lbs AI 

Applied 

0 U"l 

0 

0 

N 

I 

1.0 

I ,.... 00 0"1 0 ..-< 0 0 0 0 ..-< ..-< 

0 0 0 0 0 0 N N N N N N 

- Pounds AI - Total Acres Treated 

N 

..-< 

0 

N 

500,000 

Total Acres 

Treated 

0 

Figure 1. Spirodiclofen Total Acres Treated and Total Pounds A.I. Applied, 2005-2012 

Source: Proprietary Data, 2005-2012 

Page 3 of8 
Between 2008 and 2012, an average of85,000 lbs ofspirodiclofen were applied annually to 

315,000 acres. The majority of spirodiclofen was applied to oranges (30% of total pounds 

applied), followed by grapefruit (20%), grapes (18%), and almonds (15%). The remaining 

17% of total pounds of spirodiclofen were applied in smaller quantities to eleven other crops 

(Table 1 ). 

T a bl e 1 . S 1p1ro . d' IC I o ~ en U se on T op C rops: A verage AIR . . ate, 2008 -2012 

Crop Average Pounds Average Total Acres Average A.I. Rate 

A. I./year Treated /vear * (lbs a.i./acre) 

Oranges 25,000 105,000 0.24 

Grapefruit 17,000 6 1,000 0.27 

Grapes 16,000 56 000 0.28 

Almonds 13,000 36,000 0.35 

Other** 5,000-50 • 20,000 - 250·

8 0.40 - O.J9b 

*Total Acres Treated sums all acres treated for a crop, mcludmg those acres that receive multiple treatments. 

** Other crops: Apples, Pecans, Walnuts, Peaches, Pears, Cherries, Plums/Prunes, Apricots, Pistachios, 

Hazelnuts, Lemons. 

a Other average pounds and average total acres treated are the sum of the average values for "other" crops. 

bOther Avg. AI Rate is the average of the average rates used on "other " crops. 

Source: EPA Proprietary Data, 2008-2012 

Another measure of pesticide usage, percent crop treated, indicates the potential importance of a 

chemical to a crop. Of the top crops, a considerable portion of grapefruit (50%) were treated 

with spirodiclofen. Similarly, a sizable percentage of several crops (listed as "Other" in Table 1 ), 

including tangelos (30%) and tangerines (20%), were treated with spirodiclofen. The percent 

crop treated of all observed crops from 2004 to 20 12 can be found in the SLU A. 

Table 2 shows usage in terms of percent of total pounds a.i applied by state during the same time 

period represented in Table I (2008-2012). During this time period, the majority of 

spirodiclofen was applied in Florida (45% oftotal pounds applied) and California (40%). The 

remaining 15% of total pounds applied of spirodiclofen was applied in nine other states (Table 

2). 

Table 2. Comparison of States with Highest Use of 

Spirodiclofen- Percent of Total Pounds A.I. Applied 

Between the 2003-2007 and 2008-2012. 

2008-2012 

Average Annual = 85,000 lbs 

State %Lbs 

Florida 45 

California 40 

Other** 15 

**Other States: Texas, Georg1a, Wasbmgton, M1cbigan, Oregon, 

Pennsylvania, Virginia, Ohio, and West Virginia. 

Source: Proprietary Data, 2008-2012 

Page 4 of8 
Geographic Distribution of Spirodiclofen Usage 

The map in Figure 2 shows spirodiclofen use intensity in terms of pounds A.I. applied per 1,000 

acres of crop area grown in each state. Just as with use in terms of total pounds applied, use 

intensity of spirodiclofen is highest in Florida and California where the majority of the citrus 

crops in the U.S. are grown. Use in the mid-Atlantic and Great Lakes regions may reflect the 

need to control several mites species in grapes and pome fruit, both of which have relatively 

large acreages .in these parts of the country. 

Pounds Active Ingredient 

per 1 ,000 Crop Acres Grown 

0No0ata 

CJ <0.1 

c::J o.1 -0.2 

. 0.2 - 1 

- 1-5 

- >5 

Figure 2. Annual average agricultural use intensity of spirodiclofen (2008-2012). 

Source: Proprietary Data 

More information about this map is presented in Appendix A. 

ROLE OF SPIRODICLOFEN IN PEST MANAGEMENT 

Spirodiclofen is categorized in Mode of Action group 23 by the Insecticide Resistance Action 

Committee (an industry group of technical experts). Other members ofthis group (all also 

registered in the U.S.) are spiromesifen and spirotetramat. These pesticides are all toxic to these 

arthropods by interfering with growth regulation and lipid production. While spirodiclofen has 

not been granted reduced risk status by the EPA, the closely related spiromesifen and 

Page 5 of8 
spirotetramat do have this designation (EPA 2013). Spiromesifen is not currently registered on 

citrus fruit, the group of crops that shows highest use of spirodiclofen. 

The current labels for spirodiclofen list a wide variety of phytophagous mites, as well as t he San 

Jose scale, as target pests. Spiromesifen and spirotetramat, though identical in Mode. of Action, 

have many other types of pests on their labels, including psyllids, thrips, and whiteflies. This 

suggests that spirodiclofen has a comparatively narrow spectrum of activity. There is evidence 

that spirodiclofen is comparatively low in toxicity to at least one predatory mite, Galendromus 

occidentalis, common in tree fruits (Bostanian et al. 2009). This study did not compare 

spirodiclofen to spiromesifen or spirotetramat. However, this data suggests that spirodiclofen 

may have particular benefits in IPM programs where predatory mites are an important 

component, and target pest selectivity is a high priority. 

It is not clear at this time why there has been a noticeable drop in use of spirodiclofen since 

2010. It may be that this material is comparatively more expensive than the many other options 

available in most of the registered crops, or that there are localized increases in pest resistance to 

spirodiclofen. It is also possible that growers prefer to use spirotetramat or other materials with a 

broader pest spectrum to include pests such as San Jose scale, which can be serious pests in some 

tree fruits and nuts. BEAD notes also that spirodiclofen has a limit of one application per year in 

citrus crops, while spirotetramat has a limit expressed in total amount used per season that 

translates into two applications per year in these crops (Rogers et al. 2014). 

DATA NEEDS 

Obtaining the following information may improve future assessments conducted by the Agency 

related to the use and importance of spirodiclofen. 

Recent reports of pest resistance 

Information on comparative product performance or other aspects that underlie the 

drop in total spirodiclofen use since 201 0. 

REFERENCES 

BEAD. 2014. Spirodiclofen Screening Level Osage Analysis. Biological and Economic 

Analysis Division, Office of Pesticide Programs, U.S. Environmental Protection 

Agency. 

Page 6 of8 
Bostanian, N.J., H. A. Thistlewood, J.M. Hardman, M-C. Laurina and G. Racettea 2009. 

Effect of seven new orchard pesticides on Galendromus occident a/is in laboratory 

studies. Pest Manag Sci 65: 635-639. 

EPA. 2005. Fact Sheet for Spirodiclofen. 

Kaul, M. and D. Berwald. 2006. Preliminary Impact Analysis for Aldicarb on Major Citrus 

Crops (DP 299884). Biological and Economic Analysis Division, Office of Pesticide 

Programs, U.S. Environmental Protection Agency. 

Proprietary Data. 2002-2012. (pesticide usage data) 

Rogers, M.E., P.A. Stansly, C.C. Childers, C.W. McCoy, and H.N. Nigg. 2014 Florida Citrus 

Pest Management Guide: Rust Mites, Spider Mites, and Other Phytophagous Mites. 

Available on the web at: 

https://edis.ifas.ufl.edu/topic book florida citrus pest management guide [Accessed 

September 2014] 

Page 7 of8 
APPENDIX A 

The map included herein (Figure 2) is primarily for the use of the risk assessors in the 

Environmental Fate and Effects Division. The map provides a very broad geographical view of 

the average annual amount (in pounds) of the active ingredient applied per 1,000 acres of crop 

acres grown. These data are included in the maps because risk assessors are interested in the 

amount of a pesticide used across agricultural land. The calculated values presented in the map 

are not equivalent to an application rate (lb ai/ A). 

The data used to make these maps have several limitations. Any interpretation of the maps 

should consider the underlying data and the associated limitations carefully. 

The numerator (annual average pounds applied) is based on private market surveys of pesticide 

use in agriculture averaged over the last five years (Proprietary Data, 2008-2012). These surveys 

cover about 60 crops and are targeted in states that produce the majority of the crop. Although 

the surveys capture most of the use of a particular active ingredient in agriculture, there are 

several limitations to these surveys. 

• States with minor production of a surveyed crop are not sampled 

• Not all types of pesticides are surveyed in every crop in every year 

• Many specialty crops with very small acreages are not included in the survey 

The result ofthese limitations is that states that show no usage may actually have a small amount 

of the active ingredient being used. In some cases the displayed use intensity may be distorted 

because the surveyed crops and the reported pesticide usage may not accurately represent the 

actual pesticide usage on the crops produced in the state. 

The denominator (1,000 crop acres grown) was also obtained from the same private market 

survey database. The "Crop Acres Grown" variable represents the total acres grown in a given 

state of all of the surveyed crops. This value is independent of pesticide usage and pesticide 

registration. It is important to note that the surveyed crops (about 60) are sampled from states 

that are major producers of each crop. Therefore, there are cases where the actual crop acreage in 

a state is higher than that reported by crop acres grown in the survey because either that state 

and/or crop was not included in the survey. 

The reader should pay particular attention to the figure legends and realize that a map prepared 

for a particular chemical is not directly comparable to a map prepared for a different chemical as 

the legend bins will likely be different. 

Page 8 of8