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INTRODUCTION 

This is the Environmental Protection Agency’s (EPA or the Agency) Final Work Plan (FWP) for the 

registration review of pyraclostrobin. This work plan addresses public comments received 

concerning the Preliminary Work Plan (PWP), which was posted in the pyraclostrobin registration 

review docket (EPA-HQ-OPP-2014-0051). Pyraclostrobin belongs to the strobilurin class of 

fungicides (β-methoxyacrylate class of compounds). Strobilurins are synthetic analogs of a natural 

antifungal substance which inhibit spore germination, mycelial growth, and sporulation of the 

fungus on the leaf surface. Pyraclostrobin products are registered for use in agriculture, turf grass, 

and residential sites. There are registered food uses. 

The Agency is implementing the registration review program pursuant to Section 3(g) of the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered pesticide every 

15 years to determine whether it continues to meet the FIFRA standard for registration. Changes in 

science, public policy, and pesticide use practices occur over time. The registration review program 

is intended to make sure that, as the ability to assess risk evolves and as policies and practices 

change, all registered pesticides continue to meet the statutory standard. The public phase of 

registration review begins when the initial docket is opened for each case. Information on this 

program is provided on the Agency’s website.1

The FWP begins with any updates since the PWP was issued. Next is a summary of substantive 

comments received during the public comment period for the PWP concerning anticipated data 

needs, expected risk assessments, or the estimated timeline identified in the PWP, and a summary of 

the Agency’s responses to those comments. This section is followed by registration review planned 

data needs, risk assessments expected to be conducted, and the projected registration review timeline 

for pyraclostrobin. Lastly, there is a discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

There are no additional updates on pyraclostrobin since the PWP. 

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

During the 60-day public comment period on the Pyraclostrobin Preliminary Work Plan, which 

opened on June 25, 2014 and closed on August 25, 2014, the Agency received 6 public comments. 

Comments were submitted by The Arizona University Pest Management Center, The Center for 

Biological Diversity, The FIFRA Endangered Species Task Force (FESTF), The National Alfalfa 

and Forage Alliance, The University of Hawaii, and The Western Integrated Pest Management 

Center. The comments do not address the timeline described in the PWP, but they do address the 

planned ecological and human health risk assessments. In the PWP, EPA also solicited comments 

on the specific topics of environmental justice, water quality concerns, and trade irritants, but no 

comments or information were received on those issues. 

Summarized below are public comments that resulted in changes to the anticipated registration 

review data needs, risk assessments, or timeline, or are of a broader regulatory nature. Public 

comments and EPA responses in their entirety are located in the docket, EPA-HQ-OPP-2014-0051. 

 

1 http://www.epa.gov/oppsrrd1/registration_review/ 
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Comments submitted by the FIFRA Endangered Species Task Force (FESTF) in EPA-HQOPP-2014-0051-0012 

Comment: FESTF submitted a comment informing the Agency that the technical registrant of Pyraclostrobin is a 

member of the FESTF (or a company having met its data compensation obligations) and is entitled to rely on 

FESTF data. 

Response: The Agency thanks FESTF for its comment. 

Comments submitted by the Center for Biological Diversity (CBD) in EPA-HQ-OPP-2014-

0051-0010 

Comment: The Center for Biological Diversity’s (CBD) comments focus on the EPA’s duty to consult with the U.S. 

Fish and Wildlife Service and the National Marine Fisheries Service (the Services) on the registration review of 

pyraclostrobin in accordance with the Endangered Species Act (ESA). The CBD comments mention various aspects 

of the risk assessment process, including use of the best available data to develop endangered species risk assessments, 

and evaluation of effects on endangered and threatened species and their designated critical habitat. CBD also 

expresses concern regarding the rigor of the Agency’s preliminary determinations regarding the effects of pyraclostrobin 

on endangered and threatened (listed) species and their designated critical habitat for the pyraclostrobin registration 

review. 

 

Response: EPA has reviewed the comments from CBD on the registration review docket opening 

for pyraclostrobin and plans to address many of the concerns raised by CBD as part of the 

implementation plan for assessing the risks of pesticides to listed species based on the 

recommendations of the April 2013 National Academy of Sciences (NAS) report. EPA will address 

concerns specific to pyraclostrobin in connection with the development of its final registration 

review decision for pyraclostrobin. 

In November 2013, the EPA, along with the Services and the USDA, released a summary of their 

joint Interim Approaches for assessing risks to endangered and threatened (listed) species from 

pesticides. The Interim Approaches were developed jointly by the agencies in response to the 

National Academy of Sciences’ (NAS) recommendations and reflect a common approach to risk 

assessment shared by the agencies as a way of addressing scientific differences between the EPA and 

the Services. The NAS report outlines recommendations on specific scientific and technical issues 

related to the development of pesticide risk assessments that EPA and the Services must conduct in 

connection with their obligations under the ESA and FIFRA. 

The joint Interim Approaches were released prior to a stakeholder workshop held on November 15, 

2013. In addition, the EPA presented the joint Interim Approaches at the December 2013 Pesticide 

Program Dialogue Committee (PPDC) and State-FIFRA Issues Research and Evaluation Group 

(SFIREG) meetings. The agencies also held a stakeholder workshop in April and October 2014, 

allowing additional opportunities for stakeholders to comment on the Interim Approaches. 

Additional workshops are planned to enhance stakeholder involvement. As part of a phased, 

iterative process for developing the Interim Approaches, the agencies will also consider public 

comments on the Interim Approaches in connection with the development of upcoming 

Registration Review decisions. The details of the joint Interim Approaches are contained in the 
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white paper “Interim Approaches for National-Level Pesticide Endangered Species Act Assessments 

Based on the Recommendations of the National Academy of Sciences April 2013 Report,” dated 

November 1, 2013. 

Given that the agencies are continuing to develop and work toward implementation of the Interim 

Approaches to assess the potential risks of pesticides to listed species and their designated critical 

habitat, the ecological problem formulation supporting this Final Work Plan for pyraclostrobin does 

not describe the specific ESA analysis, including effects determinations for specific listed species or 

designated critical habitat, to be conducted during registration review. In the ecological problem 

formulation document for pyraclostrobin, EPA described the screening-level risk assessment to 

determine the potential effects of pyraclostrobin on all taxa of non-target wildlife and plants, which 

will assume that listed species and their designated critical habitats may be present in the vicinity of 

the application of pyraclostrobin. This screening-level assessment will allow EPA to focus its future 

evaluations on the types of species where the potential for effects exists once the scientific methods 

being developed by the agencies have been fully vetted. While the agencies continue to develop a 

common method for ESA analysis, the planned screening-level risk assessment for the registration 

review of pyraclostrobin will describe the level of ESA analysis completed for this particular 

registration review case. Once the agencies have fully developed and implemented the scientific 

methods necessary to complete risk assessments for endangered and threatened (listed) species and 

their designated critical habitats, these methods will be applied to subsequent analyses for 

pyraclostrobin as part of completing this registration review. 

BENEFIT AND USE COMMENTS 

The Agency received public comments from The Arizona University Pest Management Center, The 

National Alfalfa and Forage Alliance, The University of Hawaii, and The Western Integrated Pest 

Management Center on the benefits of uses of pyraclostrobin in agricultural production. 

Comments: Comments relating to the benefits and uses of pyraclostrobin were submitted by 

agricultural commodity associations, and agricultural extension services. These comments varied in 

content, but provided a range of points to be considered by the Agency in favor of the continued 

registration of pyraclostrobin. Topics of discussion included use and usage, benefits in yield, and 

integrated pest management. 

Response: The Agency appreciates the offer from various stakeholders for assistance with 

information, and will keep this in mind moving forward in the registration review process. 

PLANNED DATA NEEDS 

The planned data needs have been updated from what was included in the PWP. An acute larval 

toxicity study with both the technical grade active ingredient (TGAI) and typical end-use product 

(TEP), a honeybee adult acute oral toxicity study with a pyraclostrobin-triticonazole formulation, 

and a chronic larval honeybee study using TEP are anticipated to be required. Since the PWP was 

posted the Agency has received a passerine oral toxicity study and a honeybee adult acute oral 

toxicity study with a pyraclostrobin-triticonazole formulation. The data needs may be satisfied once 

the studies have been reviewed. 
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Table 1: Anticipated Data Needs for the Pyraclostrobin Registration Review 

Guideline 

Number2 Study Title1 Test Material 

Estimated 

Timeframe 

(Months from 

receipt of 

DCI) 

835.4400 Anaerobic Aquatic Metabolism TGAI 24 

850.6100 

Environmental chemistry method and 

independent laboratory validation (ECM/ILV) 

in water for parent and the following 

metabolite: BF 500-3 

TGAI and 

metabolite: BF 

500-3 

12 

850.1400 Freshwater fish early-life stage TGAI 12 

850.1735 Whole sediment – acute freshwater 

invertebrates TGAI 12 

850.2100 Avian oral toxicity (passerine species) TGAI 12 

NonGuideline Honeybee adult acute oral toxicity 

TGAI and for 

the following 

TEPs: 

pyraclostrobinmetiram; and 

pyraclostrobintriticonazole 

12 

NonGuideline Honeybee adult chronic toxicity TGAI and 

TEP 12 

NonGuideline Honeybee larval acute toxicity TGAI and 

TEP 12 

NonGuideline Honeybee larval chronic toxicity TGAI and 

TEP 12 

Nonguideline Residues in pollen and nectar TEP 24 

 850.3040 Field testing for pollinators TEP 24 

RISK ASSESSMENTS FOR REGISTRATION REVIEW

The most recent comprehensive human health risk assessment for pyraclostrobin was completed in 

2013 in preparation for a new use request. The most recent ecological and environmental fate risk 

assessment was completed in 2013 for the same purpose. Findings and conclusions from these risk 

assessments are summarized in the Registration Review: Preliminary Problem Formulation for Environmental 

Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for Pyraclostrobin, and 

PYRACLOSTROBIN Human Health Assessment Scoping Document in Support of Registration Review

documents 

 

2 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850 – Ecological Effects Tests – 

including renumbering and other designations or changes for some guideline studies. See “Final Test Guidelines; 

OCSPP 850 Series; Notice of Availability” 77 FR 38282, June 27, 2012. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0028 
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During registration review, the Agency anticipates the need to conduct a comprehensive ecological 

risk assessment, including an endangered species assessment, for all uses of pyraclostrobin. For 

human health, EPA does not anticipate the need to conduct a revised dietary risk assessment during 

registration review. However, since the toxicological endpoints for short- and intermediate-term 

inhalation exposures were derived using older calculation methods, the Agency will need to reassess 

these exposures using the Agency’s current risk assessment procedures. The Agency will assess 

whether recent changes to inhalation risk assessment methods will affect risk estimates. These 

updates were not included in the PWP but are now reflected in Table 2. The Agency will also 

examine the need for a volatilization assessment during Registration Review for pyraclostrobin 

based on the potential for exposure to bystanders from agricultural applications. Any changes to the 

standard operating procedures or default exposure assumptions will be considered in any new 

assessments that may be conducted. 

Table 2 below summarizes the anticipated registration review risk assessments based on the EFED 

Problem Formulation and HED Scoping Document. 

Table 2: Anticipated Risk Assessments for the Pyraclostrobin Registration Review 

Type of Risk Assessment Conduct? Notes 

Ecological and Environmental Fate 

Comprehensive ecological 

(species to be assessed include 

terrestrial and aquatic 

organisms), including 

endangered species 

Yes The most recent comprehensive risk assessment was 

completed on April 17, 2013 for the following uses: 

tomato transplants grown for home consumer market, 

sugarcane, artichoke, Belgian endive, persimmon, 

citrus, oilseed crops, bulb vegetable group, bushberry 

and caneberry groups, fruiting vegetable group, low 

growing berry subgroup (except cranberry), pome fruit 

group, small fruit/vine climbing subgroup (except 

fuzzy kiwifruit), root vegetables 1B (except sugarbeets) 

turnip greens, and homeowner ornamentals and 

landscape gardens. 

Incidents Will check for 

updates 

For a discussion of reported ecological incidents for 

pyraclostrobin, see page 16 of the Problem 

Formulation. 

Human Health 

Dietary 

Food No 
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Table 2: Anticipated Risk Assessments for the Pyraclostrobin Registration Review 

Type of Risk Assessment Conduct? Notes 

Drinking water No A new dietary exposure assessment is not anticipated 

to be needed during Registration Review unless there 

are changes to the drinking water exposure estimates 

that need to be incorporated. Partially refined acute 

and chronic dietary exposure assessments were recently 

performed including all existing uses of pyraclostrobin. 

The resulting risk estimates do not exceed EPA’s level 

of concern. The assumptions used in these 

assessments incorporated conservative inputs for 

%CT, residue levels in crops, and estimated residues in 

drinking water, and therefore, are not expected to have 

underestimated the dietary exposure and risks posed by 

pyraclostrobin. 

Occupational 

Handlers (mixers, loaders, 

applicators) 

Yes There is sufficient information available to assess 

occupational handler and post-application exposures. 

Updated occupational post-application exposure 

assessments are not expected to be needed during 

Registration Review. Due to recent changes in 

inhalation risk assessment methods, updated 

occupational handler exposure assessments may be 

needed during Registration Review. 

Post-application No 

Residential 

Handlers Yes Due to recent changes in inhalation risk assessment 

methods, updated residential handler exposure 

assessments may be needed during Registration 

Review. Residential post-application assessments are 

not expected to be conducted during Registration 

Review; however, the Agency will examine the need 

for a volatilization assessment to assess postapplication residential risk from pyraclostrobin during 

Registration Review based on the potential for 

exposure to bystanders from agricultural applications. 

Post-application No 

Other 

Aggregate Yes Evaluates the combined risk from dietary and 

residential exposures. 

Cumulative NA Unlike other pesticides for which EPA has followed a 

cumulative risk approach based on a common 

mechanism of toxicity, EPA has not made a common 

mechanism of toxicity finding with pyraclostrobin. 

Pyraclostrobin does not appear to produce a toxic 

metabolite produced by other substances. 
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Table 2: Anticipated Risk Assessments for the Pyraclostrobin Registration Review 

Type of Risk Assessment Conduct? Notes 

Tolerances Yes The current tolerance expression as listed in the 40 

CFR § 180.582 have been updated to reflect current 

policy. There are numerous pyraclostrobin maximum 

residue limits (MRLs)/tolerances. The US and Canada 

residue definitions are effectively harmonized, but 

differ from the Codex definition. The possibility for 

harmonization will be discussed during registration 

review. 

Incidents Will check for 

updates 

For a discussion of reported human incidents for 

pyraclostrobin, see page 8 of the Scoping Document 

and the Revised: Pyraclostrobin: Tier I Review of 

Human Incidents. 

TIMELINE

EPA has created the following estimated timeline for the completion of the pyraclostrobin 

registration review in Table 3 below. The projected timeline has not changed since the PWP. 

Table 3: Projected Pyraclostrobin Registration Review Timeline

Activities Estimated Date

Opening the Docket 

Open Docket and 60-day Public Comment Period June 2014 – Completed 

Close Public Comment August 2014 – Completed 

Case Development 

Final Work Plan November 2014 – Completed 

Issue DCI 2015 Jan. - March 

Data Submission 2017 Jan. - March 

60-day Public Comment Period for Draft Risk 

Assessments[1]

2018 July – Sept. 

Registration Review Decision 

60-day Public Comment Period for Proposed 

Registration Review Decision 

2019 April - June 

Registration Review Decision and Begin Post-Decision 

Follow-up 

2020 

Total (years) 6 

 

 

[1] The regulations governing Registration Review generally require the Agency to provide a public comment period of at 

least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pesticides, the Agency 

plans to provide a 60 calendar day public comment period generally for draft risk assessments. 
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NEXT STEPS 

As noted previously, the Agency plans to require several environmental fate, ecological effects 

studies for pyraclostrobin through a Data Call-In Notice, expected to be issued early in 2015.