Streptomyces Strain K61 Case 6066 Docket Number EPA-HQ-OPP-2009-0509 Registration Review Final Decision

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Docket Number EPA-HQ-OPP-2009-0509

Streptomyces Strain K61 

Registration Review Final Decision

Case 6066

PC 129069

March 2011

Approved by: ________________________ 

Keith A. Matthews, Director

Biopesticides and Pollution Prevention Division

Date: ______________________ 
Streptomyces Strain K61 Case 6066 Docket Number EPA-HQ-OPP-2009-0509 Registration Review Final Decision

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Table of Contents

Streptomyces Strain K61 (Case 6066)

I. INTRODUCTION.................................................................................................................... 4

A. Streptomyces Strain K61 General Background ................................................................. 5

B. Streptomyces Strain K61 Registered Pesticide Products................................................... 6

II. SCIENTIFIC ASSESSMENT................................................................................................ 6

A. Product Analysis (40 CFR § 158.2120)............................................................................... 6

B. Human Health ...................................................................................................................... 7

1. Acute Toxicity – Tier I (40 CFR § 158.2140) .................................................................. 7

2. Subchronic Toxicity, Developmental Toxicity, Mutagenicity, and Immunotoxicity (Tier 

II); Chronic Testing (Tier III).......................................................................................... 8

3. FQPA Assessment: Dietary Exposure and Risk Characterization ................................. 8

4. Occupational Exposure and Risk Characterization ....................................................... 11

5. Endocrine Disruptors...................................................................................................... 11

6. Human Health Risk Characterization............................................................................. 12

C. Environmental Assessment ............................................................................................... 12

1. Effects on Nontarget Organisms – Tier I (40 CFR § 158.2060)..................................... 12

2. Environmental Fate, Ecological Exposure, and Environmental Expression – Tiers II and 

III (40 CFR § 158.2060) ................................................................................................ 15

3. Endangered Species Assessment..................................................................................... 15

4. Environmental Risk Characterization............................................................................. 15

D. Product Performance (Efficacy) (40 CFR § 158.2070)................................................... 16

E. Incidents.............................................................................................................................. 16

F. Public Comments................................................................................................................ 16

G. Water Quality..................................................................................................................... 17

H. Trade Irritants ................................................................................................................... 17

I. Environmental Justice ........................................................................................................ 17

III. FINAL REGISTRATION REVIEW DECISION............................................................ 18

IV. BIBLIOGRAPHY................................................................................................................ 18

V. GLOSSARY OF ACRONYMS AND ABBREVIATIONS ............................................... 22

VI. APPENDIX .......................................................................................................................... 24
Streptomyces Strain K61 Case 6066 Docket Number EPA-HQ-OPP-2009-0509 Registration Review Final Decision

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Streptomyces Strain K61 (Case 6066) Registration Review Team

Human Health and Environmental Effects 

Joel Gagliardi (BPPD)

Zigfridas Vaituzis (BPPD)

Risk Management

Anna Gross (BPPD)

Office of General Counsel

Philip Ross, Esq. 
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I. INTRODUCTION

This document is the Environmental Protection Agency’s (EPA or the Agency) Final

Registration Review Decision for Streptomyces Strain K61 and is being issued in accordance 

with 40 CFR §§ 155.57 and 155.58. A registration review decision is the Agency's 

determination whether a pesticide meets, or does not meet, the standard for registration in the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). With regard to registered 

pesticides containing Streptomyces Strain K61, EPA determined that the FIFRA standard of 

registration has been met. For further information on Streptomyces Strain K61, additional 

documents can be found in EPA’s public docket (EPA-HQ-OPP-2009-0509) at 

www.regulations.gov. 

FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, mandated the 

continuous review of existing pesticides. All pesticides distributed or sold in the United States 

must generally be registered by EPA, based on scientific data showing that they will not cause 

unreasonable risks to human health or the environment when used as directed on product 

labeling. 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 of no unreasonable adverse effects to human health or the environment. 

Changes in science, public policy, and pesticide use practices will occur over time. Through the 

registration review program, the Agency periodically reevaluates pesticides to make sure that as 

change occurs, products in the marketplace can be used safely. Information on this program is 

provided at: http://www.epa.gov/oppsrrd1/registration_review/. 

In 2006, the Agency implemented the Registration Review program pursuant to FIFRA 

section 3(g). EPA will review each registered pesticide every 15 years to determine whether it 

continues to meet the FIFRA standard for registration. 

In accordance with 40 CFR § 155.50, the Agency formally initiated registration review 

for Streptomyces Strain K61 (Case 6066). The following timeline highlights significant events 

that have occurred during the registration review of Streptomyces Strain K61: 

 September 2009 – Publication of the Streptomyces griseoviridis Strain K61 Summary 

Document in the docket (EPA-HQ-OPP-2009-0509) for a 60-day public comment period. 

The Summary Document also included the preliminary work plan (PWP). No comments 

were received.

 October 2009 – A request by the registrant, Verdera Oy, to change the name of the a.i. to 

Streptomyces K61 was approved as part of a product formulation amendment. This 

change was made due to an inability to positively identify this species as Streptomyces 

griseoviridis.

1

 Both the label and Confidential Statement of Formula (CSF) were updated 

 

1 The species identification was under question during the initial registration of Streptomyces Strain K61, but the 

issue was resolved with help from a letter written by David Lambert (Associate Professor of Plant Pathology at the 

University of Maine) on May 19, 1993. In it, he argued that the lack of spiral spore chain morphology that was the 

basis for the determination that the strain was not Streptomyces griseoviridis was not a reliable enough characteristic 

for negative identification. This determination was supported by a May 26, 1993 memo from C. Schaffer to S. 

Lewis, in which it was recommended that BPPD accept the identification of the strain as Streptomyces griseoviridis. 

Based on a February 2, 2005 letter from the German Collection of Microorganisms and Cell Cultures (DSM), 
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with the revised a.i. name. In order to harmonize both product registrations containing 

this a.i., Verdera Oy will also be required, as part of the registration process, to update the 

label and CSF for Mycostop® G Biofungicide (EPA Reg. No. 64137-9). This change 

affects only the nomenclature of the a.i. It does not have an impact on any of the 

previously completed risk assessments, which are still valid because all of the submitted 

studies were conducted using the same test material that is now registered as 

Streptomyces Strain K61. 

 January 2010 – Publication of the Streptomyces Strain K61 Final Work Plan, which 

stated that the most recent exposure and risk assessments still supported the registration 

of the currently registered pesticide products containing Streptomyces Strain K61 and that 

these products appeared to have met the requirement of registration review under 40 CFR 

§ 155.50. The Final Work Plan also documented the modification of the active 

ingredient name designation from Streptomyces griseoviridis Strain K61 to Streptomyces 

Strain K61.

 July 2010 – Publication of the Streptomyces Strain K61 Proposed Decision for a 60-day

public comment period. No comments were received. The document proposed a final 

registration review decision affirming that the data on file continue to adequately support 

the registered pesticides containing Streptomyces Strain K61.

 March 2011 - Publication of the Streptomyces Strain K61 Registration Review Final 

Decision, which formally determined that registered pesticides containing Streptomyces 

Strain K61 meet the current standards of registration under FIFRA.

The information evaluated to support Streptomyces Strain K61, as published in the 

Summary Document, continues to support the active ingredient as summarized herein. The status 

of this and other registration review cases is available at: 

http://www.epa.gov/oppsrrd1/registration_review/reg_review_status.htm. Additional 

information on Streptomyces Strain K61 is available on the Biopesticides and Pollution 

Prevention Division’s website in the form of a succinct fact sheet

(http://www.epa.gov/oppbppd1/biopesticides/ingredients/factsheets/factsheet_129069.htm). 

 On October 26, 2007, the Agency issued a Final Rule in the Federal Register (FR) on the 

data requirements to support registration of biochemical and microbial pesticides and updated 

definitions for both biochemical and microbial pesticides (72 FR 61002). This rule became 

effective on December 26, 2007. The data and information summarized below were considered 

in light of these requirements. 

A. Streptomyces Strain K61 General Background

Streptomyces Strain K61 is a naturally occurring soil bacterium initially isolated from 

peat in Finland. It is believed to act against disease-causing fungi in at least two ways: by

colonizing plant roots to deprive disease organisms of space and nourishment; and by producing 

antifungal compounds. It is closely related to the bacterial species that produces the antibiotic 

streptomycin. Streptomyces Strain K61 forms light colored colonies consisting of brown 

substrate mycelium, beige aerial mycelium, and long rectiflexible smooth spore chains. As a 

 

however, currently available data demonstrate that it is not possible that the strain in question is of the S. 

griseoviridis species, and the a.i. has been re-classified as Streptomyces Strain K61. 
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microbial active ingredient, products containing Streptomyces Strain K61 are registered for

control of seed, root and stem rot, and to prevent wilt of ornamentals, vegetables and tree and 

forest seedlings caused by Fusarium, Alternaria, and Phomopsis. Streptomyces Strain K61 also 

suppresses root rots of Pythium, Phytophthora and Rhizoctonia in greenhouse plants and is used 

as a seed treatment for seed or soil borne damping off and early root rot. Streptomyces Strain 

K61 is approved for use on all raw agricultural commodities and can be applied to seeds, soil, 

roots and transplants, or as a dip or spray.

Based on data submitted to the Agency, Streptomyces Strain K61 is not expected to infect 

humans or to cause harmful effects if ingested. EPA determined, however, that users may

experience mild eye and skin irritation as well as adverse effects on lungs. Current product 

labels specify required personal protective equipment (PPE). Adverse human health or 

ecological risks are not expected as a result of exposure to this active ingredient when used as 

directed on product labels. Moreover, the assessment conducted in the course of this 

Registration Review and included in the docket indicates that all data requirements were

adequately addressed in the course of Streptomyces Strain K61 registration. 

B. Streptomyces Strain K61 Registered Pesticide Products

There are currently two Streptomyces Strain K61 end use products (EPs) registered with 

EPA, both of which are listed in the table below. There are no registered manufacturing use 

products (MUPs) for Streptomyces Strain K61.

EPA Reg. No. Registration Name Company Name Current Status % Streptomyces (a.i.)

64137-5 Mycostop®

Biofungicide

Verdera Oy Conditionally 

Registered 

(1993)

35%2

64137-9 Mycostop® G 

Biofungicide

Verdera Oy Registered 

(2002)

4%

II. SCIENTIFIC ASSESSMENT

A. Product Analysis (40 CFR § 158.2120) 

The data and information submitted to support applications for registration for the active 

ingredient Streptomyces Strain K61 were reassessed and found sufficient to fulfill current 

product chemistry data requirements (40 CFR § 158.2120) for all the use patterns described 

above. Adequate product analysis data for Streptomyces Strain K61 were found in the 

submissions and reviews associated with the original registration of Mycostop®(EPA Reg. No. 

64137-5) in 1993 and in the reassessment documents associated with this registration review. A 

list of supporting product chemistry studies (including MRIDs) can be found within the ‘Studies 

Supporting Registration Review of Streptomyces Strain K61’ in the bibliography. Mycostop® G 

(EPA Reg. No. 64137-9) was determined to be substantially similar to Mycostop®. The 

 

2 BPPD reviewed all applicable data and approved a product formulation amendment for Mycostop® Biofungicide 

(EPA Reg. No. 64137-5) on October 30, 2009, which changed the concentration of a.i. from 30% to 35%. The label 

was updated to reflect the new concentration (associated MRIDs: 475768-01, 476780-01 and 477719-01).
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manufacturer submitted new product chemistry data to support the product’s registration but 

relied on previously submitted Mycostop®data to support all other data requirements. A 

summary of the the specific physical and chemical characteristics of Streptomyces Strain K61 is

found in Table 1 of the Appendix.

B. Human Health

1. Acute Toxicity – Tier I (40 CFR § 158.2140) 

The acute toxicity data submitted with the original registration of Mycostop® (EPA Reg. 

No. 64137-5), as well as the justification to bridge to that data in support of the Mycostop® G

(EPA Reg. No. 64137-9) registration, were reassessed and found sufficient to address current 

acute toxicity data requirements (40 CFR § 158.2140). Acute toxicity results are discussed 

below. A summary of the Streptomyces Strain K61 acute toxicity profile, categorized by

guideline, is available in Table 2 of the Appendix. A complete list of the acute toxicity studies 

can be found in the Bibliography.

 Acute Oral Toxicity/Pathogenicity (Office of Chemical Safety and Pollution Prevention 

(OCSPP) Guideline 885.3050) – Rats (21 males, 21 females): MRID 418211-12. The data 

show no clinically significant signs in rats. Streptomyces Strain K61 was not detected in 

kidney, brain, liver, lungs, spleen, mesenteric lymph nodes, or in blood or urine samples and 

cleared from the feces and cecum following day two. Necropsy studies showed no significant 

signs of abnormalities. There were significant reductions in the weights of dosed males 

compared to controls at all study times and in the dosed females on day 8 and day 22. In the 

absence of pyrogenic effects or any sign of infectivity, however, the test organism was not 

toxic, infective or pathogenic to rats. 

 Acute Injection Toxicity/Pathogenicity (OSCPP Guideline 885.3200) – Mice (38 males, 39 

females): MRID 418211-15. An acute intraperitoneal injection of 5000 mg of the test 

article/Kg killed all males and females within 1 day of treatment. 1000 mg/Kg and 500 mg/Kg 

doses also caused some deaths within 2 days of dosing. This indicates a toxic response to the 

test article rather than an infectious process, which was confirmed by the mortality caused by 

the heat-killed test article. The toxin appears to be heat stable. Adverse clinical signs returned 

to normal by day 5 in surviving mice except for one female with a distended abdomen and two 

with enlarged spleens. The spleens showed no sign of the test article. The LD50 for 

intraperitoneal injection was estimated to be 1306 mg/Kg for males, 870 mg/Kg for females 

and 1042 mg/Kg for both sexes combined. 

 Acute Pulmonary Toxicity/Pathogenicity (OCSPP Guideline 885.3150) – Rats (23 male, 23 

female): MRID 418211-14. Generally, instillation of bacterial spores into rat lungs will result 

in a small number of deaths (which was seen in this study). Also, large numbers of spores are 

usually recovered from the lungs shortly after dosing – with successively lower numbers of 

spores seen at later time intervals and concurrent increases in the spores isolated from the 

caecal contents – as a result of clearance from the lungs via the trachea and subsequent 

ingestion. The present study was not typical in this regard. The authors reported that 

microscopic examination of the dosing preparation showed densely packed inter-meshing 

mycelia in aggregations of 100 mm to 200 mm, whereas spores normally have dimensions of 1
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mm x 2 mm. They concluded that the size of the mycelial masses would not penetrate into the 

peripheral lungs and would be rapidly cleared from the airways by the pulmonary mucociliary

escalator system. Evidence regarding the infectivity/pathogenicity of the test organism is, 

therefore, inconclusive since only small numbers of viable organisms appeared to have reached 

the lower lungs. Since there was no proliferation of the organism by the end of the study and 

because of the large particle size of the preparation, however, the authors concluded that 

Streptomyces Strain K61 would not present an infectious hazard under field conditions. 

 Acute Pulmonary Toxicity/Pathogenicity (OCSPP Guideline 885.3150) – Rats (200 male, 

200 female): MRIDs 424415-01, 424415-02. Streptomyces Strain K61 caused death in 54% 

of treated male and 48% of treated female rats with 45% (male) and 40% (female) mortality 

occurring within the first 2 days after intratracheal instillation. This high death rate may be due 

partially to the large size of the test organism; Streptomyces Strain K61 caused sufficient 

mortality to provoke concern about pulmonary exposure to significant amounts of the 

bacterium. Dosage was 0.1 mL of a 3.46 x 108 CFU/mL suspension. 

 Acute Eye Irritation (OCSPP Guideline 870.2400) – Rabbits (6 males): MRID 418211-16. 

Small numbers of spores of Streptomyces Strain K61 were found in the treated eyes of all 6 

rabbits at 24 and 72 hours post-treatment, but none thereafter. Instillation of Streptomyces

Strain K61 (>107viable spores per eye) elicited transient, mild conjunctival irritation. 

 Acute Dermal Toxicity/Pathogenicity (OCSPP Guideline 885.3100) – Rabbits (5 males. 5 

females): MRIDs 418211-13, 422980-08. Streptomyces Strain K61 was not toxic to rabbits 

when a single 2 g/Kg dose was administered dermally. Rabbit body weights were not affected 

by an exposure of 2 g/Kg of Streptomyces Strain K61. 

 Primary Dermal Irritation (OCSPP Guideline 870.2500) – Guinea Pigs (20 females): 

MRID 418211-17. Moderate reactivity (55% of responders) of guinea pig skin to Mycostop®

(EPA Reg. No. 64137-5) was recorded on day 2 following challenge of sensitized animals. 

While no determination was made of the amount of viable Streptomyces Strain K61 spores 

used in any of the animal exposures and the dose formulations records are inconsistent, the 

basic conclusion that the end use product is a skin sensitizer is still valid. Mycostop®is a 

moderate skin sensitizer. Dosage was 0.1 mL of a 3% w/v dilution of Mycostop®in distilled 

water. 

 

2. Subchronic Toxicity, Developmental Toxicity, Mutagenicity, and Immunotoxicity 

(Tier II); Chronic Testing (Tier III)

Tier II and Tier III studies were not required for Streptomyces Strain K61 based on the 

lack of acute toxicity observed in the Tier I studies for the EPs.

3. FQPA Assessment: Dietary Exposure and Risk Characterization

Section 408(c)(2)(A)(i) of the Federal Food, Drug, and Cosmetic Act (FFDCA) allows 

EPA to establish an exemption from the requirement for a tolerance (the legal limit for a 

pesticide chemical residue in or on a food) only if EPA determines that the exemption is “safe.” 

Section 408(c)(2)(A)(ii) of FFDCA defines “safe” to mean that “there is a reasonable certainty
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that no harm will result from aggregate exposure to the pesticide chemical residue, including all 

anticipated dietary exposures and all other exposures for which there is reliable information.” 

This includes exposure through drinking water and in residential settings, but it does not include 

occupational exposure. Pursuant to section 408(c)(2)(B) of FFDCA, in establishing or 

maintaining in effect an exemption from the requirement of a tolerance, EPA must take into 

account the factors set forth in section 408(b)(2)(C) of FFDCA, which require EPA to give 

special consideration to exposure of infants and children to the pesticide chemical residue in 

establishing a tolerance and to “ensure that there is a reasonable certainty that no harm will result 

to infants and children from aggregate exposure to the pesticide chemical residue... . ” 

Additionally, section 408(b)(2)(D) of FFDCA requires that the Agency consider “available 

information concerning the cumulative effects of a particular pesticide's residues” and “other 

substances that have a common mechanism of toxicity.”

EPA performs a number of analyses to determine the risks from aggregate exposure to 

pesticide residues. First, EPA determines the toxicity of pesticides. Second, EPA examines 

exposure to the pesticide through food, drinking water, and through other exposures that occur as 

a result of pesticide use in residential settings.

Consistent with section 408(b)(2)(D) of FFDCA, EPA has reviewed the available 

scientific data and other relevant information, and considered its validity, completeness, and 

reliability and the relationship of this information to human risk. EPA has also considered 

available information concerning the variability of the sensitivities of major identifiable 

subgroups of consumers, including infants and children.

On the basis of acute toxicity data discussed above and summarized by guideline in Table 

2 in the Appendix, the data requirements required for FQPA risk assessments for Streptomyces 

Strain K61 have been satisfied.

a. Aggregate Exposures

In examining aggregate exposure, section 408 of FFDCA directs EPA to consider 

available information concerning exposures from the pesticide residue in food and all other nonoccupational exposures, including drinking water from ground water or surface water and 

exposure through pesticide use in gardens, lawns, or buildings (residential and other indoor 

uses).

i. Dietary Exposure and Risk Characterization

Dietary exposure to Streptomyces Strain K61 is expected to be minimal. As the mode of 

action of Streptomyces Strain K61 is through root colonization, the majority of applications are 

to seeds and soil. Certain foliar applications are permitted for the purposes of suppressing 

Botrytis infection and promoting growth; however, direct applications to crops are highly diluted 

and residues are not expected to persist. Regardless, any risk associated with dietary exposure is 

expected to be insignificant. Streptomyces Strain K61 is a naturally occurring microbe found in 

soils throughout the world, and there are no known reports of any deleterious effects associated 

with its consumption. Additionally, the acute toxicity data on file with the Agency confirm its 

lack of acute toxicity and support an exemption from the requirement of a tolerance (40 CFR § 

180.1120). 
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ii. Drinking Water Risk Characterization

Exposure to Streptomyces Strain K61 via drinking water when the pesticide is used is not 

likely to be greater than current/existing exposures. Although Streptomyces Strain K61 is found 

naturally, it does not thrive in aquatic environments. There are no aquatic use sites for the 

pesticide, so exposure in drinking water is not expected. In addition, there is no evidence of 

adverse effects from oral, dermal, or inhalation exposure to this microbial agent (refer to the 

acute toxicity summaries above and in Table 2 of the Appendix). Data on file with the Agency

confirm the lack of oral toxicity/pathogenicity of Streptomyces Strain K61 and continue to 

support its exemption from the requirement of a tolerance.

iii. Non-Occupational, Residential Risk Characterization 

There are no residential uses for Streptomyces Strain K61. Non-occupational exposures 

are not expected; in the event of accidental exposure, no non-occupational risks are anticipated. 

The acute toxicity data on file with the Agency show a lack of acute toxicity for all routes of 

exposure. 

b. Cumulative Effects

Section 408(b)(2)(D)(v) of the FFDCA requires the Agency to consider the cumulative 

effects of exposure to Streptomyces Strain K61 and to other substances that have a common 

mechanism of toxicity. These considerations include the possible cumulative effects of such 

residues on infants and children. No mechanism of toxicity in mammals has been identified for 

Streptomyces Strain K61; therefore, no cumulative effect with other related compounds is 

anticipated. Because the data available demonstrate a low toxicity potential for Streptomyces 

Strain K61, the likelihood of adverse dietary effects is expected to be minimal. 

c. Determination of Safety for U.S. Population, Infants, and Children

FFDCA section 408(b)(2)(C) provides that EPA shall assess the available information 

about consumption patterns among infants and children, special susceptibility of infants and 

children to pesticide chemical residues, and the cumulative effects on infants and children of the 

residues and other substances with a common mechanism of toxicity. In addition, FFDCA 

section 408(b)(2)(C) requires EPA to apply an additional ten-fold margin of safety for infants 

and children in the case of threshold effects to account for prenatal and postnatal toxicity and the 

completeness of the database, unless EPA determines that a different margin of safety will 

protect infants and children. Margins of exposure (safety), which are often referred to as 

uncertainty factors, are incorporated into EPA’s risk assessment either directly, through the use 

of a margin of exposure analysis, or by using uncertainty (safety) factors in calculating a dose 

level that poses no appreciable risk.

Based on the available acute toxicity data for Streptomyces Strain K61, along with the 

expected exposure profile, EPA believes that there is reasonable certainty that no harm will 

result from aggregate exposure to the United States population, including infants and children, to 

the residues of Streptomyces Strain K61. This includes all anticipated dietary exposures and all 
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other exposures for which there is reliable information. The Agency has arrived at this 

conclusion because the submitted data available on Streptomyces Strain K61 do not demonstrate

significant toxic effects on mammals. Thus, there are no threshold effects of concern and, as a 

result, the provision requiring an additional margin of safety does not apply. Further, the 

considerations of consumption patterns, special susceptibility, and cumulative effects do not 

apply to pesticides without a demonstrated significant adverse effect.

 

d. Food Tolerance Exemptions

On April 21, 1993, a Notice of Filing was published in the Federal Register for

Streptomyces sp. strain K61: exemption from the requirement of a tolerance [50 FR 21403]. 

Under 40 CFR 180.1120, the biological pesticide Streptomyces sp. strain K61 is exempted from 

the requirement of a tolerance in or on all raw agricultural commodities when used as a fungicide 

for the treatment of seeds, cuttings, transplants, and plants of agricultural crops in accordance 

with good agricultural practices. 

4. Occupational Exposure and Risk Characterization

 Due to the results of the acute pulmonary toxicity study, EPA is concerned about 

repeated exposure of workers, farm personnel or other agriculturists to Streptomyces Strain K61. 

Though the primary applications of Streptomyces Strain K61 are either soil-incorporated or seed 

treatments, foliar applications are permitted, which increases the probability of repeated 

respiratory exposure. Mycostop® was also found to be a moderate skin sensitizer. To mitigate 

the effects of occupational exposure to this a.i., standard personal protective equipment (PPE) is 

required by the labels for both Mycostop®and Mycostop® G, including long-sleeved shirt and 

long pants, waterproof gloves, and shoes plus socks. In addition, a dust/mist respirator or a 

NIOSH-approved respirator is required by the labels along with a four hour restricted-entry

interval (REI) for both products. 

5. Endocrine Disruptors

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential 

adverse outcomes from exposure to chemicals. Collectively, these studies include acute, 

subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, 

developmental, reproductive, and general or systemic toxicity. These studies include endpoints 

which may be susceptible to endocrine influence, including effects on endocrine target organ 

histopathology, organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, 

reproductive loss, and sex ratios in offspring. For ecological hazard assessments, EPA evaluates 

acute tests and chronic studies that assess growth, developmental and reproductive effects in 

different taxonomic groups. As part of its registration decision, EPA reviewed these data and 

selected the most sensitive endpoints for relevant risk assessment scenarios from the existing 

hazard database. However, as required by FFDCA section 408(p), Streptomyces Strain K61 is 

subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including 

pesticide active and other ingredients) may have an effect in humans or wildlife similar to an 

effect produced by a “naturally occurring estrogen, or other such endocrine effects as the 
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Administrator may designate.” The EDSP employs a two-tiered approach to making the 

statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to identify

the potential of a chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or 

T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the 

potential to interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP 

where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available 

data. Tier 2 testing is designed to identify any adverse endocrine-related effects caused by the 

substance, and establish a dose-response relationship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between 

October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 

chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. Streptomyces

Strain K61 is not among the group of 58 pesticide active ingredients on the initial list to be 

screened under the EDSP. Accordingly, EPA will issue future EDSP orders/data call-ins, 

requiring the submission of EDSP screening assays for Streptomyces Strain K61. For further 

information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, 

future lists, the test guidelines and the Tier 1 screening battery, please visit our website: 

http://www.epa.gov/endo/.

6. Human Health Risk Characterization 

The human hazard and exposure assessments for Streptomyces Strain K61 indicate that 

the risks to human health are negligible to non-existent when products containing Streptomyces 

Strain K61 are used in accordance with their respective labels. These assessments are considered 

complete and current, and they satisfy the standards of registration review. All microbial

pesticide toxicology data requirements applicable to human health effects determinations for 

Streptomyces Strain K61 were considered and are fulfilled. 

C. Environmental Assessment

1. Effects on Nontarget Organisms – Tier I (40 CFR § 158.2060) 

Based on data and information submitted to support applications for registration, as well 

as the associated assessments evaluating those data, all microbial pesticide nontarget organism 

and environmental fate data requirements for the Streptomyces Strain K61 were considered and 

are fulfilled. Ecological data submitted for the registration of Mycostop® and cited for the 

registration of Mycostop® G are discussed below. (Additional testing on nontarget insects, 

marine/estarine animals, and nontarget plants was waived during registration because the 

conditions under which such tests are required were not met.) A summary of the Streptomyces 

Strain K61 ecological effects is available in Table 3 of the Appendix. A complete list of the 

nontarget organism and environmental fate studies can be found in the bibliography.

 Avian Oral Toxicity/Pathogenicity (OCSPP Guideline 885.4050) – Mallard (50 birds in 

10 treatment groups of 5 each): MRID 418211-20. No mortalities occurred in any of the 

control groups (negative and sterile filtrate) or among the treated birds (2500 mg/Kg or 

approximately 2.45 x 109cfu/Kg per day for five days). All birds were normal in appearance 

and behavior throughout the test period. There were no apparent effects on body weight or 
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feed consumption between the control and the treated groups. All birds were euthanized 

using carbon dioxide at the termination of the study and then subjected to gross necropsy. 

The results were not found to be remarkable except for two male birds in the control groups 

which had single plaques in their air sacs. In the treatment group, one male bird was small, 

with reduced muscle mass and feather loss on the rump. Two males and one female were 

found to have plaques on their air sacs, and a second female had plaques on and in the lungs 

and a somewhat pale spleen. The study is scientifically sound and demonstrated an LD50 > 

2,500 mg/Kg. This indicates that Streptomyces Strain K61 is not toxic or pathogenic to 

waterfowl. The study fulfils EPA Guideline requirements for an avian oral 

pathogenicity/toxicity test. 

 Avian Oral Toxicity/Pathogenicity (OCSPP Guideline 885.4050) – Northern Bobwhite (50 

birds in 10 treatment groups of 5 each): MRID 418211-19. No mortalities occurred in either of 

the control groups (negative or attenuated) and 2 occurred among the Streptomyces treated birds 

(2500 mg/Kg or approximately 2.45 x 109cfu/Kg per day for five days). Due to the nature of 

lesions observed in the necropsy, neither death was considered to be treatment-related. All other 

birds were normal in appearance and behavior throughout the test period, except for one bird that 

exhibited limping, lethargy and a ruffled appearance. These conditions were not thought to be 

treatment-related. There were no apparent effects on body weight or feed consumption between 

the control and the treated groups. All birds were euthanized using carbon dioxide at the 

termination of the study and then subjected to gross necropsy. The results were not found to be 

remarkable. The study was scientifically sound and demonstrated an LD50 > 2,500 mg/Kg. This 

indicates that Streptomyces Strain K61 is not toxic or pathogenic to upland game birds. The 

study fulfilled EPA Guideline requirements for an avian oral pathogenicity/toxicity test. 

 Freshwater Fish Toxicity/Pathogenicity (OCSPP Guideline 885.4200) – Rainbow trout (80 

fish): MRID 418211-21. Five-gallon glass jars holding 15 liters of solution were used as the 

exposure chambers. Groups of 10 fish were exposed to a control (water) and five test 

concentrations, plus a killed-spore concentration equivalent to the high test level. One hundred 

percent mortality occurred in the killed spore group (4.0 x 104 CFU/mL) at day 16, with 70% and 

90% mortality in the 2.0 x 104 CFU/mL group at day 25 and 26 respectively. Due to sporadic 

mortality, an LC50 could not be calculated but was estimated to be greater than 40.8 mg/L (4.0 x 

108 CFU/mL) at 7, 14, and 21 days and greater than 10.2 mg/L at 30 days. A NOAEC was 

determined to be 5.1 x 103 CFU/mL and there was no observed infectivity after 30 days. The 

possibility of toxicity was indicated by the killed spore and the 2.0 x 104test concentration 

results, but a lack of toxicity at the 4.0 x 104test concentration made this interpretation 

questionable. (Problems with nonspecific toxicity when testing fungal preparations have been 

observed in the past and have been related to the autoclaving process used to kill the fungal 

spores for the killed spore control.) All trout were normal in appearance and behavior 

throughout the test period. The dissolved oxygen ranged from 8.0 to 10.2 mg/L in the renewed 

solutions and 4.8 to 10.6 mg/L in the expired solutions, pH ranged from 7.6 to 8.4 in the renewed 

solutions and 7.1 to 8.3 in the in the expired solutions, and the temperature ranged from 11 to 

13°C in both solutions. This study showed sporadic fish mortality and failed to demonstrate a 

definitive LC50 value due to the absence of a dose-response trend with the observed mortality. 

The study results were not adequate for making a risk assessment. 
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 Freshwater Fish Toxicity/Pathogenicity (OCSPP Guideline 885.4200) – Rainbow trout 

(70 fish): MRID 430903-01. The 30-day static renewal toxicity/pathogenicity study of 

Mycostop®(EPA Reg. No. 64137-5) to rainbow trout (Oncorhynchus mykiss) was conducted 

by Kemira Agro Oy. Single replicates of 10 fish each were exposed to Streptomyces Strain 

K61 concentrations of 0.25 x 105, 0.50 x 105, 1.0 x 105, 2.0 x 105, and 4.0 x 105 CFU/mL in 

dilution water, plus a dilution water control and a killed-spore treatment of 4.0 x 105 CFU/mL. 

The dietary dose in the food offering was 10% of the water exposure concentration. Water 

chemistry measurements of dissolved oxygen, pH, and temperature indicated that overall,

adequate water quality was maintained throughout the term of the experiment. Gentle aeration 

was supplied to all test chambers to maintain the dissolved oxygen levels. The day 1, day 2, 

day 3, and day 4 LC50 values were 2.8 x 105, 1.6 x 105, 1.2 x 105, and 0.8 x 105 CFU/mL, 

respectively. The concentration-response line slopes for days 1-4 were 15, 7.7, 7.7, and 7.7, 

respectively. The slope of the day 5 through day 30 concentration-response line was 15. The 

30-day NOAEC was 0.50 x 105 CFU/mL based on the lack of mortality, statistically significant 

growth effects, and sublethal/abnormal effects at this concentration. All surviving fish ate 

normally and showed an increase in length and weight on day 30 as compared to the 

representative group on day 0. No lesions or tissue discolorations were noted in any surviving 

fish at the end of the study. 

 Freshwater Aquatic Invertebrate Toxicity/Pathogenicity (OCSPP Guideline 885.4240) –

Daphnia (100 Daphnia magna in 5 treatment groups): MRID 418211-22. A 21-day static 

renewal study was conducted to determine the toxicity and/or pathogenicity of Streptomyces 

Strain K61 spores to Daphnia magna. A control group was tested against four treatment 

groups, including a maximum nominal dose exposure of 1.0 x 106 CFU/mL and low and 

median doses of 104and 105 CFU/mL, plus a dose of 1.0 x 106 CFU/mL of heat-killed 

spores. No significant differences (P>0.05) were found between the control and the exposure 

levels for reproduction and time to first brood. All of the offspring produced during the 

study appeared normal. Mean survival was 100% for control and low level concentration, 

75% for the middle concentration, and 0% for the high concentration and killed spore 

treatment. Mortality from killed spore treatments has been reported from previous studies

and is thought to be caused by creating a toxic environment through the autoclaving process, 

which could have contributed to the effects observed in this test. A day 21 EC50 was 

calculated to be approximately 190 mg/L (1.9 x 105 CFU/mL). Daphnid growth was found 

to be significantly affected at the middle concentration (1 x 105 CFU/mL). The NOAEC was 

found to be 1.0 x 104 CFU/mL, the LOEC was 1.0 x 105 CFU/mL, and the MATC was found 

to be 3.2 x 104 CFU/mL. The mean temperatures of the test solutions were 20.6 + 0.5oC for 

the old and 20.5 + 0.5oC for the new solutions. The pH values for the renewed solutions 

ranged from 7.8 to 8.5 (mean = 8.3 + 0.2) and for the expired solutions ranged from 4.8 to 

8.8 (mean = 8.2 + 0.9). Dissolved oxygen concentrations in the renewed solutions ranged 

from 8.0 to 8.5 mg/L (94% to 100% saturation) at 21oC (mean = 8.3 + 0.2 mg/L) and in the 

expired solutions ranged from 0.7 to 9.5 mg/L (8% to 112% saturation) at 21oC (mean = 7.1

+ 2.4 mg/L). The study is scientifically sound and demonstrated an EC50 = 190 ppm (1.9 x

105 CFU/mL). This indicates that Streptomyces Strain K61 is not toxic or pathogenic to 

Daphnia magna. The study fulfils EPA Guideline requirements for an acute toxicity test for 

an aquatic invertebrate.
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 Toxicity/pathogenicity to Honey Bees (OCSPP Guideline 885.4380) – (25 bee pupae per 

treatment): MRID 418211-23. Three treatment levels, representing 240, 760 and 2400 ppm

at a specific activity of 9.8 x 108cfu/g of diet, were tested along with an attenuated control 

and a negative control. Two replicates were tested at each concentration with 25 bees per 

replicate. Mortalities occurred in both of the control groups (negative and attenuated) and in 

all 3 of the treatment groups. The mortalities in the negative and attenuated control groups 

were 30% and 62%, respectively, while those in the 240, 760, and 2400 ppm concentrations 

averaged 20%, 26% and 28%, respectively. The pattern of mortality was not found to be 

dose responsive and did not appear to be treatment-related. The LC50 was determined to be 

greater than 2400 ppm and the NOAEC was 2400 ppm, which was the highest concentration 

tested. Due to nonspecific mortality in the controls, however, the study is considered 

supplemental. The results were reliable enough to indicate that MYCOSTOP®is not toxic or 

pathogenic to the honey bee. This study also satisfies the data requirements for nontarget 

insect testing (OCSPP Guideline 885.4340). 

2. Environmental Fate, Ecological Exposure, and Environmental Expression – Tiers II 

and III (40 CFR § 158.2060) 

Environmental fate data requirements (i.e., Tiers II, III, and IV) were not triggered for 

Streptomyces Strain K61 because results of the nontarget toxicity/pathogenicity Tier I studies did 

not demonstrate hazard to nontarget organisms.

3. Endangered Species Assessment 

Through a re-evaluation of the ecological effects data and EPA reviews of Streptomyces 

Strain K61, the Agency has determined that adverse effects will not occur to nontarget organisms 

as a result of the labeled applications of Streptomyces Strain K61. In addition, Streptomyces 

Strain K61 is a naturally occurring soil bacterium that suppresses the growth of plant pathogenic 

fungi. Reduction or loss of these fungi will not affect habitat or other resources required by 

threatened and endangered species. 

Since EPA has determined that no effects are anticipated for any nontarget species 

exposed to Streptomyces Strain K61 as a result of the labeled applications, effects to federallylisted threatened and endangered species and their designated critical habitats are also not 

expected. As a result of these analyses, the Agency has determined that registered uses of 

Streptomyces Strain K61 will have “no effect” on endangered or threatened terrestrial or aquatic 

species as listed by the U.S. Fish and Wildlife Service (USFWS) and the National Marine 

Fisheries Services (NMFS) and will not destroy or adversely modify designated critical habitat. 

The ‘Endangered Species Assessment for Streptomyces Strain K61’ can be found in the 

Registration Review docket EPA-HQ-OPP-2009-0509.

4. Environmental Risk Characterization

Based on the reviews of the aforementioned nontarget organism and environmental fate 

information, and the endangered species assessment, the Agency has determined that 

unreasonable adverse effects to nontarget organisms or the environment are not likely to result 

when products containing Streptomyces Strain K61 are used in accordance with their respective 
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labels. These assessments are considered complete and current, and they satisfy the standards of 

registration review. 

D. Product Performance (Efficacy) (40 CFR § 158.2070)

Product performance data must be developed for all microbial pesticides to ensure 

efficacy when used in accordance with labeling directions and commonly accepted pest control 

practices. The Agency waived all requirements to submit such efficacy data unless the pesticide 

product bears a claim to control public health pests, although the Agency reserves the right to 

require, on a case-by-case basis, submission of efficacy data for any pesticide product registered 

or proposed for registration. The Streptomyces Strain K61 pesticide products are fungicides 

intended for agricultural use and do not have labeled uses for public health pests. The Agency

has not required submission of efficacy data to support any of the claims on the current labels. 

E. Incidents

Two instances of hypersensitivity were reported by Verdera Oy prior to EPA registration. 

The first incident was reported in 1986, the details of which are included in MRID No. 418211-

18. One part-time summer trainee at the Espoo Research Centre in Finland had symptoms of a 

mild alveolar reaction to Mycostop® (EPA Reg. No. 64137-5). The alveolar reaction could have 

been due to exposure to biological dust from Mycostop®, though there were indications that the 

incident might have been avoided by careful use of the safety equipment that was recommended 

and provided. In 1991, a research associate in a lab in Fort Collins, CO, experienced dizziness, 

faintness, difficulty breathing and dilated pupils after treating seed with Mycostop®. The 

individual had a history of allergies and asthma and was not wearing the required face mask 

when exposed. The symptoms disappeared in approximately one hour, and no medical attention 

was sought. These incidents do not have any bearing on the hazard or risk assessed pertaining to 

the use of registered Streptomyces Strain K61 pesticide products in accordance with their product 

labels. Both individuals recovered completely, and no other employees working with Mycostop® 

have reported any problems. Label language on Streptomyces Strain K61 products is appropriate 

and sufficient to protect users/handlers of these products. 

The Office of Pesticide Programs’ Incident Data System (IDS) indicates no other reports of 

adverse human, domestic animal, or environmental incidents for products containing 

Streptomyces Strain K61. In addition, no incidents were reported in response to the Agency

request for such information in the Streptomyces griseoviridis Preliminary Work Plan and 

Summary Document.

F. Public Comments

In accordance with 40 CFR § 155.50, the Agency formally initiated registration review 

for Streptomyces Strain K61 in September 2009, with the opening of a docket (Docket Number 

EPA-HQ-OPP-2009-0509) and the issuance of a Summary Document for a 60-day public 

comment period. The Agency received no comments in response to the Streptomyces 

griseoviridis Summary Document and the initial opening of the docket. A Federal Register (FR) 

Notice, published on July 28, 2010, announced the placement of the Streptomyces Strain K61

Proposed Decision document into the docket, and initiated a 60-day public comment period to 
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allow for consideration of any new information in advance of a Final Decision. EPA did not 

receive any comments during the 60-day public comment period for the Streptomyces Strain K61

registration review proposed decision.

G. Water Quality

Streptomyces Strain K61 has not been identified as a cause of impairment for any water 

bodies listed as impaired under Section 303(d) of the Clean Water Act, based on information 

provided at: 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=88

5. In addition, no Total Maximum Daily Loads (TMDLs) have been developed for Streptomyces 

Strain K61, based on information provided 

at:http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_i

d=885&p_pollutant_group_name=PESTICIDES. More information on impaired water bodies 

and TMDLs can be found at http://www.epa.gov/owow/tmdl/. The Agency solicited comments 

when the Summary Document was published in September 2009; however, no comments, data, 

or information regarding the existence of any water quality issues associated with Streptomyces 

Strain K61 were received. 

H. Trade Irritants

Trade irritants are not expected for Streptomyces Strain K61. Through the registration 

review process, the Agency is soliciting information on trade irritants and, to the extent feasible, 

will take steps toward facilitating irritant resolution. Growers and other stakeholders are asked 

to comment on any trade irritant issues resulting from lack of Maximum Residue Levels (MRLs) 

or disparities between U.S. tolerances or exemptions from tolerance and MRLs or exemptions 

from MRLs in key export markets, providing as much specificity as possible regarding the nature 

of the concern. Trade irritants are not expected for Streptomyces Strain K61because there are no 

U.S. tolerances for Streptomyces Strain K61, nor are there Codex MRL’s. The Agency did not 

receive any comments regarding the existence of any trade irritant issues associated with 

Streptomyces Strain K61 following issuance of the Summary Document. 

 I. Environmental Justice

EPA seeks to achieve environmental justice—the fair treatment and meaningful 

involvement of all people, regardless of race, color, national origin, or income—in the 

development, implementation, and enforcement of environmental laws, regulations, and policies. 

To help address potential environmental justice issues, the Agency sought information, as 

explained in the Summary Document, on groups or segments of the population who, as a result of 

their location, cultural practices, or other factors, may have atypical, unusually high exposure to 

registered pesticide products containing Streptomyces Strain K61 compared to the general 

population. The Agency did not receive any comments. At this time, EPA does not believe that 

use of the registered pesticide products containing Streptomyces Strain K61 will cause harm to or 

a disproportionate impact on at-risk communities. 

For additional information regarding environmental justice issues, please visit EPA’s 

website at: http://www.epa.gov/compliance/environmentaljustice/index.html.
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III. FINAL REGISTRATION REVIEW DECISION

The Agency has determined that no additional data are required at this time to support 

current registrations containing Streptomyces Strain K61. The Agency has considered 

Streptomyces Strain K61 in light of the standard for registration and safety factors in FIFRA and 

FFDCA, as amended by FQPA. EPA has found that there are not likely to be any unreasonable 

adverse effects to the U.S. population in general, and to infants and children in particular, or to 

nontarget organisms or the environment from the use of registered pesticide products containing 

Streptomyces Strain K61 when currently required label instructions are followed. In addition, 

EPA has made a “No Effect” determination for endangered and threatened species, and their 

designated critical habitat, for Streptomyces Strain K61. The Agency has found that it is not 

necessary to conduct a new risk assessment for this case and is, therefore, issuing a final decision 

in accordance with 40 CFR Section 155.53(c)(2) and 40 CFR Section 155.58. 

In accordance with 40 CFR §§ 155.57 and 155.58, the Agency’s final registration review 

decision is that the standards for Registration Review have been met and that the registrations of 

the two products containing Streptomyces Strain K61 be maintained. 

IV. BIBLIOGRAPHY

A. Studies Supporting Registration Review of Streptomyces Strain K61

41821100 Kemira Oy (1991) Submission of Chemistry and Toxicity Data in Support of Mycostop 

New Application Registration, and Petition for an Exemption from the Requirement of 

Tolerance. Transmittal of 23 studies.

41821101 Pulkkanen, H. (1990) Product Identity and Disclosure of Ingredients: Mycostop. 

Unpublished study prepared by Kemira Oy. 10 p.

41821102 Bjorkqvist, B.; Leppanen, L. (1989) Determination of the Active Ingredient of 

Streptomyces griseoviridis in Cucumber and Cabbage. Unpublished study prepared by 

Keira Oy. 10 p.

41821103 Bjorkqvist, B.; Leppanen, L.; Lahdenpera, M. (1990) Determination of Heptaenic 

Antibiotic Residues in Cucumber Fruit and Dill after Mycostop Treatment. Unpublished 

study prepared by Kemira Oy. 12 p.

41821104 Raatikainen, N. (1990) Determination of the Antifungal Antibiotic Produced by Mycostop 

in the Peat. Unpublished study prepared by University of Kuopio. 16 p.

41821105 Tuomisto, J. (1989) Summary Research Report. Unpublished study prepared by 

University of Kuopio. 8 p.

41821106 Pulkkanen, H. (1990) Manufacturing Process: Mycostop. Unpublished study prepared by 

Kemira Oy. 8 p.

41821107 Pulkkanen, H. (1990) Unintentional Ingredient Discussion: Mycostop. Unpublished study 

prepared by Kemira Oy. 7 p.

41821108 Pulkkanen, H. (1991) Mycostop (Streptomyces Griseoviridis): Determination of Viability. 

Unpublished study prepared by Kemira Oy. 6 p.

41821109 Pulkkanen, H. (1990) Certification of Limits: Mycostop. Unpub- lished study prepared by 
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Kemira Oy. 7 p.

41821110 Snelson, A. (1990) Determination of Color, Physical State, Odor, Density, and pH of 

Mycostop: Lab Project Number: CO8074: 2. Unpublished study prepared by IIT Research 

Institute. 19 p.

41821111 Pulkkanen, H. (1991) Mycostop (Streptomyces Griseoviridis): Determination of Storage 

Stability. Unpublished study prepared by Kemira Oy. 6 p.

41821112 Hossack, D.; Baker, M.; Denton, S. (1989) Acute Oral Toxicity and 

Infectivity/Pathogenicity to Rats of Streptomyces griseoviridis (Mycostop): Lab Project 

Number: 89953D/RKY 114/0/AC. Unpub- lished study prepared by Huntingdon Research 

Centre Ltd. 28 p.

41821113 Liggett, M. (1989) Acute Dermal Toxicity to Rabbits of Streptomyces griseoviridis, 

(Mycostop): Lab Project Number: 89892D/RKY 114/1/ AC. Unpublished study prepared 

by Huntingdon Research Centre Ltd. 12 p.

41821114 Hossack, D.; Baker, M.; Denton, S. (1989) Acute Pulmonary Toxicity and 

Infectivity/Pathogenicity to Rats of Streptomyces Griseo- viridis (Mycostop): Lab Project 

Number: 89954D/RKY 114/0/AC. Unpublished study prepared by Huntingdon Research 

Centre Ltd. 31 p.

41821115 Sherwood, R. (1990) Acute Intraperitoneal Toxicity Limit Testing of Streptomyces 

griseoviridis, a Microbial Pesticide: Lab Project Number: LO8279. Unpublished study 

prepared by IIT Research Institute. 26 p.

41821116 Liggett, M.; Hossack, D.; Baker, M. (1989) Irritant Effects on the Rabbit Eye of 

Streptomyces griseoviridis (Mycostop): Lab Project Number: 891076D/RKY 114/4/SE. 

Unpublished study prepared by Huntingdon Research Centre Ltd. 15 p.

41821117 Lackenby, F. (1991) Skin Sensitization Study in the Guinea Pig (Magnusson-Kligman 

Maximization Test): Lab Project Number: 5383- 18R. Unpublished study prepared by 

Hazleton UK. 22 p.

41821118 Pulkkanen, H. (1990) Hypersensitivity Incident Reporting Mycostop. Unpublished study 

prepared by Kemira Oy. 4 p.

41821119 Beavers, J.; Smith, G. (1990) Mycostop (Streptomyces Griseoviridis) An Avian Oral 

Pathogenicity and Toxicity Study in the Bobwhite: Lab Project Number: 293-102. 

Unpublished study prepared by Wildlife International Ltd. 20 p.

41821120 Beavers, J.; Smith, G. (1990) Mycostop (Streptomyces Griseoviridis) An Avian Oral 

Pathogenicity and Toxicity Study in the Mallard: Lab Project Number: 293-103. 

Unpublished study prepared by Wildlife International Ltd. 20 p.

41821121 England, D. (1990) A 30-Day Static Renewal Toxicity and Pathogeni- city Evaluation on 

the Effects of Streptomyces griseoviridis to Rainbow Trout (Oncorhynchus mykiss): Lab 

Project Number: 38678. Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 26 p.

41821122 England, D. (1990) A 21-Day Static Renewal Toxicity and Pathogenicity Evaluation on 

the Effects of Streptomyces griseovirivis to Daphnia magna: Lab Project Number: 38679. 

Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 23 p.

41821123 Hoxter, K.; Smith, G. (1990) A Dietary Pathogenicity and Toxicity Study with the Honey 

Bee: Lab Project Number: 293-101. Unpublished study prepared by Wildlife International 

Ltd. 14 p.

42298000 E.R. Butts Intl., Inc. (1992) Submission of product chemistry and toxicity data to support 

the registration of the microbiocide Mycostop. Transmittal of 8 studies.
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42298001 Mohammadi, O. (1992) Taxonomic Identification of Mycostop Biofungicide. 

Unpublished study prepared by Kemira Oy. 13 p.

42298002 American Cell Type Culture Collection (1983) Culture Identification (Streptomyces 

cultures): Lab Project Number: 564. Unpublished study. 11 p.

42298003 Franke, J. (1990) Streptomyces Characterization: Lab Project Number: SC 2344. 

Unpublished study prepared by American Type Cell Culture Collection. 13 p.

42298004 Kroppenstedt, R. (1992) Identification of Your Isolates Strain SS6 (90-551), SS61 (90-

552), SS12 (91-469), and SS31 (91-470). Unpublished study prepared by Deustche 

Sammlung von Mikroorganismen und Zellkuluten GmbH. 61 p.

42298005 Mohammadi, O. (1992) Antibiotic Sensitivity of Streptomyces griseoviridis Strain SS61. 

Unpublished study prepared by Kemira Oy. 6 p.

42298006 Pulkannen, H. (1992) Manufacturing Process--Mycostop: Supplement to MRID 

41821106. Unpublished study prepared by Kemira Oy. 10 p.

42298007 Pulkannen, H. (1992) Mycostop (Streptomyces griseoviridis) Determination of Storage 

Stability: Supplement to MRID 41821111. Unpublished study prepared by Kemira Oy. 7 

p.

42298008 Liggert, M. (1989) Acute Dermal Toxicity to Rabbits of Streptomyces griseoviridis, 

Mycostop: Supplement to MRID 41821113. Unpublished study prepared by Huntingdon 

Research Centre Ltd. 5 p.

42441500 Kemira Oy. (1992) Submission of toxicity data to support the registration of MYCOSTOP 

biofungicide. Transmittal of 2 studies.

42441501 Mega, W. (1992) Sensitivity of Detection of Streptomyces griseoviridis for 

Toxicity/Pathogenicity Testing of Rats: Final Report: Lab Project Number: L08363. 

Unpublished study prepared by IIT Research Institute. 21 p.

42441502 Mega, W. (1992) Pulmonary Toxicity/Pathogenicity Testing of Streptomyces 

griseoviridis following Acute Intrachael Challenge in Rats: Final Report: Lab Project 

Number: L08363. Unpublished study prepared by IIT Research Institute. 146 p.

43090300 Kemira Agro Oy (1994) Submittal of Pathogenicity Data in Support of Registration of 

Mycostop Biofungicide. Transmittal of 1 study.

43090301 Bowman, J.; Sword, M. (1994) A 30-Day Static Renewal Toxicity and Pathogenicity 

Evaluation on the Effects of Mycostop (Streptomyces griscoviridis) to Rainbow Trout 

(Oncorhynchus mykiss): Final Report: Lab Project Number: 41072. Unpublished study 

prepared by Analytical Bio-Chemistry Laboratories, Inc. 287 p.

45511400 Kemira Agro OY (2001) Submission of Product Chemistry Data in Support of the 

Application for Registration of Mycostop G Biofungicide. Transmittal of 2 Studies.

45511401 Seiskari, P. (2001) Product Chemistry Data of Mycostop G Biofungicide: Lab Project 

Number: PCD MYCOSTOP G. Unpublished study prepared by Kemira Agro Oy. 27 p.

45511402 Klausner, K. (2001) Physical and Chemical Characteristics Data of Streptomyces K61 KF 

Formulation: Lab Project Number: 00-6000-G1. Unpublished study prepared by Toxikon 

Corp. 21 p.

45623100 Kemira Agro Oy (2002) Submission of Product Chemistry Data in Support of the 

Application for Registration of Mycostop G Biofungicide. Transmittal of 1 Study.

45623101 Seiskari, P. (2002) Product Chemistry Data (Addendum) of Mycostop G Biofungicide: 

Lab Project Number: PCD MYCOSTOP G. Unpublished study prepared by Kemira Agro 

Oy. 13 p.
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47576800 Verdera Oy (2008) Submission of Product Chemistry Data in Support of the Amended 

Registration of Mycostop Biofungicide. Transmittal of 1 Study.

47576801 Seiskari, P. (2008) Updated Product Chemistry Data of Mycostop Biofungicide. Project 

Number: REPORT/162/2. Unpublished study prepared by Verdera Oy. 17 p.

47678000 Verdera Oy (2009) Submission of Product Chemistry Data in Support of the Amended 

Registration of Mycostop Biofungicide. Transmittal of 1 Study.

47678001 Korteniemi, M. (2009) Supplement to Updated Product Chemistry Data of Mycostop 

Biofungicide: Streptomyces griseoviridis Strain K61 @ 35%. Project Number: 162/2. 

Unpublished study prepared by Verdera Oy. 45 p.

47771900 Verdera Oy (2009) Submission of Product Chemistry Data in Support of the Amended 

Registration of Mycostop Biofungicide. Transmittal of 1 Study.

47771901 Seiskari, P. (2009) Second Supplement to Updated Product Chemistry Data of Mycostop 

Biofungicide. Project Number: 160/3. Unpublished study prepared by Verdera Oy. 14 p.

B. Environmental Protection Agency Risk Assessment Memoranda

Barsoum, I. 2002. Product Chemistry review of Mycostop G Biofungicide. U.S. EPA, Washington, D.C. 

Memorandum dated April 1, 2002.

Barsoum, I. 2002. Review of follow-up data submitted by Verdera Oy for product Mycostop G. U.S. EPA, 

Washington, D.C. Memorandum dated October 10, 2002.

Barsoum, I. 2008. Review of an updated product chemistry study of the product Mycostop Biofungicide. U.S. 

EPA, Washington, D.C. Memorandum dated December 16, 2008.

Barsoum, I. 2009. Review of supplemental data submitted by the registrant in response to a deficiency letter 

sent by the Agency regarding the registration of the product Mycostop Biofungicide. U.S. EPA, 

Washington, D.C. Memorandum dated March 31, 2009.

Schaffer, C. 1991. SACB Review of Data Submitted by Kemira Oy to Support the Registration of Mycostop. 

U.S. EPA, Washington, D.C. Memorandum dated September 28, 1991.

Schaffer, C. 1992. SACB Review of Data Submitted by Kemira Oy to Support the Registration of Mycostop. 

U.S. EPA, Washington, D.C. Memorandum dated August 12, 1992.

Schaffer, C. 1992. SAB Review of Acute Pulmonary Toxicity/Pathogenicity Data Resubmitted by Kemira Oy 

to Support the Registration of Mycostop. U.S. EPA, Washington, D.C. Memorandum dated September 

17, 1992.

Schaffer, C. 1992. SAB Review of Data Submitted by Kemira Oy to Support the Exemption from Tolerance 

for Mycostop. U.S. EPA, Washington, D.C. Memorandum dated November 3, 1992.

Schaffer, C. 1992. SAB comment on the bridging of data from the resubmitted Acute Pulmonary 

Toxicity/Pathogenicity Data to the Acute Oral Toxicity/Pathogenicity study by Kemira Oy to Support the 

Registration of Mycostop. U.S. EPA, Washington, D.C. Memorandum dated November 10, 1992.

Schaffer, C. 1993. SAB Review of Additional Information Regarding the Taxonomic Classification of 

Mycostop, Submitted for Registration by Kemira Oy. U.S. EPA, Washington, D.C. Memorandum dated 

May 26, 1993.
Streptomyces Strain K61 Case 6066 Docket Number EPA-HQ-OPP-2009-0509 Registration Review Final Decision

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Schneider, W. 1990. OPP Scientific Assessment of the January 12, 1990, Kemira Oy Notification of a Small 

Scale Field Test of a Non-indigenous Strain of Streptomyces griseoviridis. U.S. EPA, Washington, D.C. 

Memorandum dated April 4, 1990.

Sjoblod, R. 1988. Mammalian toxicology data requirements for registration of the microbial pesticide 

Mycostop. U.S. EPA, Washington, D.C. Memorandum dated December 16, 1988.

Sjoblod, R. 1993. Mycostop Biofungicide: Company Response to Pulmonary Exposure/Toxicity Issues. U.S. 

EPA, Washington, D.C. Memorandum dated January 15, 1993.

Vaituzis, Z. 1991. Kemira Oy Notification of a Small Scale Field Test of a Non-indigenous Strain of 

Streptomyces griseoviridis. U.S. EPA, Washington, D.C. Memorandum dated May 31, 1991.

Wozniak, C. 2002. Review of the Mammalian Toxicity, Pathogenicity, Hypersensitivity and Irritation 

Potential of Streptomyces griseoviridis relative to establishment of an appropriate restricted entry 

interval. U.S. EPA, Washington, D.C. Memorandum dated July 18, 2002.

V. GLOSSARY OF ACRONYMS AND ABBREVIATIONS 

APHIS Animal and Plant Health Inspection Service

BPPD Biopesticides and Pollution Prevention Division

BRADs Biopesticides Registration Action Documents

°C degrees Celsius

CFR Code of Federal Regulations

cfu colony-forming unit

cm centimeter

EC50 half maximal effective concentration

EDSP Endocrine Disruptor Screening Program

EEC estimated environmental concentration. The estimated pesticide concentration in an 

environment, such as a terrestrial ecosystem.

EPA Environmental Protection Agency (the Agency)

FFDCA Federal Food, Drug, and Cosmetic Act

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FQPA Food Quality Protection Act

FR Federal Register

g grams

g/kg grams per kilogram

kg kilograms

L liter

LC50 median lethal concentration. A statistically derived concentration of a 

substance that can be expected to cause death in 50% of test animals. It is 

usually expressed as the weight of substance per weight or volume of water, 

air, or feed (e.g., mg/L, mg/kg, or ppm).

LD50 median lethal dose. A statistically derived single dose that can be expected to cause 

death in 50% of the test animals when administered by the route indicated (oral, 

dermal, inhalation). It is expressed as a weight of substance per unit weight of 

animal (e.g., mg/kg). 

LOC level of concern

LOEC lowest observable effect concentration

mg milligrams

mg/kg milligrams per kilogram

mg/L milligrams per liter

mL milliliter
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mL/kg milliliters per kilogram

MRID Nos. Master Record Identification Numbers

NOAEC no observable adverse effect concentration

NOEC no observable effect concentration

OECD Organization for Economic Cooperation and Development

OPP Office of Pesticide Programs

OCSPP Office of Chemical Safety and Pollution Prevention

PC Code Pesticide Chemical Code

ppm parts per million 

PWP preliminary work plan

SAR systemic acquired resistance

TGAI technical grade of the active ingredient

TMDLs Total Maximum Daily Loads

TSA trypticase soy agar

USDA United States Department of Agriculture
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VI. APPENDIX

TABLE 1. Product Analysis Data Requirements for Streptomyces Strain K61 (40 CFR § 158.2120)

Data Requirement

(OCSPP Guideline)

Results MRID Numbers

Product Chemistry and Composition

Product Identity

(885.1100)

Submitted data do not completely satisfy the requirement of product identity for 

Streptomyces Strain K61 (Mycostop®)

418211-01

418211-02

418211-03

418211-04

418211-05

Product Identity

(885.1100)

Submitted data completely satisfy the requirement of product identity for 

Streptomyces Strain K61 (Mycostop®and Mycostop® G).

Mycostop®:

422980-01

422980-02

422980-03

422980-04

422980-05

Mycostop®G:

455114-01 

Manufacturing Process

(885.1200)

Submitted data do not completely satisfy the requirement of manufacturing 

process for Streptomyces Strain K61 (Mycostop®)

418211-06

Manufacturing Process

(885.1200)

Submitted data completely satisfy the requirement of manufacturing process for 

Streptomyces Strain K61 (Mycostop®and Mycostop® G).

Mycostop®

422980-06

Mycostop®G:

455114-01

Deposition of a Sample 

in a Nationally 

Recognized Culture 

Collection

(Not applicable)

A deposit of Streptomyces Strain K61 has been made in both the American Type 

Culture Collection and at the German Collection of Microorganisms and Cell 

Cultures.

422980-02

422980-04

Discussion of 

Formation of 

Unintentional 

Ingredients

(885.1300)

Submitted data completely satisfy the requirement of discussion of formation of 

unintentional ingredients for Streptomyces Strain K61 (Mycostop®and Mycostop® 

G).

Mycostop®

418211-07

Mycostop®G:

455114-01

Analysis and Certified Limits

Analysis of Samples

(885.1400)

Submitted data completely satisfy the requirement of analysis of samples for 

Streptomyces Strain K61 (Mycostop®and Mycostop® G).

Mycostop®

418211-08

475768-01

476780-01

477719-01

Mycostop®G:

455114-01

Certification of Limits 

(885.1500)

Submitted data completely satisfy the requirement of certification of limits for 

Streptomyces Strain K61 (Mycostop®and Mycostop® G).

Mycostop®

418211-00

475768-01

Mycostop®G:

455114-01

Physical and Chemical Characteristics

Color

(830.6302)

Mycostop®: Hue: 2.5 Y, Value: 9, Chroma: 2

Mycostop® G: Hue: 2.5 yr, Value: 8.5, Chroma: 4

418211-10

455114-02

Physical State

(830.6303)

Mycostop®: Brown-tan color, fine powdery solid. Not free-flowing.

Mycostop® G: Free-flowing powder.

418211-10

455114-02
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Data Requirement

(OCSPP Guideline)

Results MRID Numbers

Odor

(830.6304)

Mycostop®: Sweaty, fishy, putrid, bitter

Mycostop® G: Smells of mold

418211-10

455114-02

Stability to Normal and 

Elevated Temperatures, 

Metals, and Metal Ions

(830.6313)

The Agency has not required that these data be submitted for Streptomyces Strain 

K61. 

Not applicable

Storage Stability

(830.6317)

Mycostop®: below +8°C, viability over 108 CFU/g for 6 months

Mycostop® G: +4°C, viable > 12 months; +28°C, viable for 6 months

418211-11

422980-07

455114-02

Miscibility

(830.6319)

N/A Not applicable

Corrosion 

Characteristics

(830.6320)

N/A Not applicable

pH

(830.7000)

Mycostop®(1%): 5.63

Mycostop® G (1%): 7.68

418211-10

455114-02

Viscosity

(830.7100)

N/A Not applicable

Density/Relative 

Density/Bulk Density 

(Specific Gravity)

(830.7300)

Mycostop®: 28.68 lb/ft3

Mycostop® G: 7.68 lb/ft3

418211-10

455114-02

TABLE 2. Toxicology Data Requirements for Streptomyces Strain K61 (40 CFR § 158.2140)

Data Requirement

(OCSPP Guideline)

Results MRID Number

Tier I

Acute Oral 

Toxicity/Pathogenicity

(885.3050)

The data show no clinically significant signs in rats. Streptomyces Strain K61 was 

not detected in kidney, brain, liver, lungs, spleen, mesenteric lymph nodes, or in 

blood or urine samples, and cleared from the feces and cecum following day two. 

Necropsy studies showed no significant signs of abnormalities. There were 

significant reductions in the weights of dosed males compared to controls at all 

study times and in the dosed females on day 8 and day 22. In the absence of 

pyrogenic effects or any sign of infectivity, however, the test organism was not 

toxic, infective or pathogenic to rats. 

Classification: Acceptable

418211-12

Acute Pulmonary 

Toxicity/Pathogenicity

(885.3150)

Generally, instillation of bacterial spores into rat lungs will result in a small 

number of deaths (which was seen in this study). Also, large numbers of spores 

are usually recovered from the lungs shortly after dosing – with successively 

lower numbers of spores seen at later time intervals and concurrent increases in 

the spores isolated from the caecal contents – as a result of clearance from the 

lungs via the trachea and subsequent ingestion. The present study was not typical 

in this regard. The authors reported that microscopic examination of the dosing 

preparation showed densely packed inter-meshing mycelia in aggregations of 

100mm to 200 mm, whereas spores normally have dimensions of 1mm x 2 mm. 

They concluded that the size of the mycelial masses would not penetrate into the 

peripheral lungs and would be rapidly cleared from the airways by the pulmonary 

mucociliary escalator system. Evidence regarding the infectivity/pathogenicity of 

the test organism is, therefore, inconclusive, since only small numbers of viable 

organisms appeared to have reached the lower lungs. Since there was no 

proliferation of the organism by the end of the study and because of the large 

418211-14

418211-15
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Data Requirement

(OCSPP Guideline)

Results MRID Number

particle size of the preparation, however, the authors concluded that Streptomyces 

Strain K61 would not present an infectious hazard under field conditions. 

Classification: Uncceptable

Acute Pulmonary 

Toxicity/Pathogenicity

(885.3150)

Streptomyces Strain K61 caused death in 54% of treated male and 48% of treated 

female rats with 45% (male) and 40% (female) mortality occurring within the first 

2 days after intratracheal instillation. This high death rate may partially be due to 

the large size of the test organism; Streptomyces Strain K61 caused sufficient 

mortality to provoke concern about pulmonary exposure to significant amounts of 

the bacterium. Dosage was 0.1 mL of a 3.46 x 108 CFU/mL suspension. 

Classification: Acceptable

424415-01

424415-02

Acute Injection 

Toxicity/Pathogenicity

(885.3200)

An acute intraperitoneal injection of 5000 mg of the test article/Kg killed all males 

and females within 1 day of treatment. 1000 mg/Kg and 500 mg/Kg doses also 

caused some deaths within 2 days of dosing. This indicates a toxic response to the 

test article rather than an infectious process, which was confirmed by the mortality 

caused by the heat-killed test article. The toxin appears to be heat stable. Adverse 

clinical signs returned to normal by day 5 in surviving mice except for one female 

with a distended abdomen and two with enlarged spleens. The spleens showed no 

sign of the test article. The LD50 for intraperitoneal injection was estimated to be 

1306 mg/Kg for males, 870 mg/Kg for females and 1042 mg/Kg for both sexes 

combined.

Classification: Acceptable

418211-15

Hypersensitivity 

Incidents 

(885.3400)

Two instances of hypersensitivity were reported by Verdera Oy prior to EPA 

registration. The first incident was reported in 1986, the details of which are 

included in MRID No. 418211-18. One part-time summer trainee at the Espoo 

Research Centre in Finland had symptoms of a mild alveolar reaction to 

Mycostop® (EPA Reg. No. 64137-5). The alveolar reaction could have been due 

to exposure to biological dust from Mycostop®, though there were indications that 

the incident might have been avoided by careful use of the safety equipment that 

was recommended and provided. In 1991, a research associate in a lab in Fort 

Collins, CO experienced dizziness, faintness, difficulty breathing and dilated 

pupils after treating seed with Mycostop®. The individual had a history of 

allergies and asthma and was not wearing the required face mask when exposed. 

The symptoms disappeared in approximately one hour and no medical attention 

was sought. These incidents do not have any bearing on the hazard or risk 

assessed pertaining to the use of registered Streptomyces Strain K61 pesticide 

products in accordance with their product labels. Both individuals recovered 

completely and no other employees working with Mycostop® have reported any 

problems.

418211-18

Cell Culture

(885.3500)

Not required because Streptomyces Strain K61 is not a virus (refer to test note #4 

of 40 CFR § 158.2140(d)).

Not applicable

Acute Oral Toxicity

(870.1100)

Not applicable to the TGAI test substance. Not applicable

Acute Dermal Toxicity

(870.1200)

Not applicable to the TGAI test substance. Not applicable 

Acute Inhalation 

Toxicity

(870.1300)

Not applicable to the TGAI test substance. Not applicable

Acute Eye Irritation

(870.2400)

Not applicable to the TGAI test substance. Not applicable

Primary Dermal 

Irritation

(870.2500)

Not applicable to the TGAI test substance. Not applicable
Streptomyces Strain K61 Case 6066 Docket Number EPA-HQ-OPP-2009-0509 Registration Review Final Decision

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Data Requirement

(OCSPP Guideline)

Results MRID Number

Tiers II and III

Not required for Streptomyces Strain K61 based on the lack of acute toxicity/pathogenicity in the Tier I studies.

Additional Studies

Acute Dermal Toxicity*

(870.1200)

Streptomyces Strain K61 was not toxic to rabbits when a single 2 g/Kg dose was 

administered dermally. Rabbit body weights were not affected by an exposure of 

2 g/Kg of Streptomyces Strain K61. 

Classification: Acceptable

418211-13

422980-08

Acute Eye Irritation*

(870.2400)

Small numbers of spores of Streptomyces Strain K61 were found in the treated 

eyes of all 6 rabbits at 24 and 72 hours post-treatment, but none thereafter. 

Instillation of Streptomyces Strain K61 (>107viable spores per eye) elicited 

transient, mild conjunctival irritation. 

Classification: Acceptable – Toxicity Category IV. 

418211-16

Primary Dermal 

Irritation*

(870.2500)

Moderate reactivity (55% of responders) of guinea pig skin to Mycostop®(EPA 

Reg. No. 64137-5) was recorded on day two following challenge of sensitized 

animals. While no determination was made of the amount of viable Streptomyces 

Strain K61 spores used in any of the animal exposures and the dose formulations 

records are inconsistent, the basic conclusion that the end use product is a skin 

sensitizer is still valid. Mycostop®is a moderate skin sensitizer. Dosage was 0.1 

mL of a 3% w/v dilution of Mycostop®in distilled water. 

Classification: Acceptable

418211-17

*

Not currently in the data requirements table in 40 CFR § 158.2140 for the TGAI test substance.

TABLE 3. Nontarget Organism and Environmental Fate Data Requirements for Streptomyces Strain 

K61 (40 CFR § 158.2150)

Data Requirement

(OCSPP Guideline)

Results MRID Number

Tier I

Avian Oral Toxicity

(885.4050)

The avian oral LD50 was greater than 2,500 mg/kg body weight, based on results from 

tests on both mallards and northern bobwhites. 

Classification: Acceptable

418211-20

418211-19

Avian Inhalation 

Toxicity/Pathogenicity

(885.4100)

Not required, as the nature of Streptomyces Strain K61 does not indicate potential 

pathogenicity to birds or relatedness to any known bird pathogens (refer to test note #3 

of 40 CFR § 158.2150(e)).

Not applicable

Wild Mammal 

Toxicity/Pathogenicity

(885.4150)

Not required for Streptomyces Strain K61 because the results of the tests required by 

40 CFR § 158.2140 are adequate and appropriate for assessment of hazards to wild 

mammals (refer to test note #4 of 40 CFR § 158. 2150(e)).

Not applicable

Freshwater Fish 

Toxicity/Pathogenicity

(885.4200)

This study showed sporadic fish mortality and failed to demonstrate a definitive LC50

value due to the absence of a dose-response trend with the observed mortality. The 

study results were not adequate for making a risk assessment. 

Classification: Unacceptable

418211-21

Freshwater Fish 

Toxicity/Pathogenicity

(885.4200)

The 30-day static renewal toxicity/pathogenicity study of Streptomyces Strain K61 to 

rainbow trout (Oncorhynchus mykiss) was conducted by Kemira Agro Oy. Single 

replicates of 10 fish each were exposed to Streptomyces Strain K61 concentrations of 

0.25x105, 0.50x105, 1.0x105, 2.0x105, and 4.0x105 CFU/mL in dilution water plus a 

dilution water control and a killed-spore treatment of 4.0x105 CFU/mL. The dietary 

dose in the food offering was 10% of the water exposure concentration. The 30-day 

NOAEC was 0.50x105 CFU/mL based on the lack of mortality, statistically significant 

growth effects, and sublethal/abnormal effects at this concentration. All surviving fish 

ate normally and showed an increase in length and weight on day 30 as compared to the 

representative group on day 0. No lesions or tissue discolorations were noted in any 

430903-01
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Data Requirement

(OCSPP Guideline)

Results MRID Number

surviving fish at the end of the study.

Classification: Acceptable

Freshwater Invertebrate 

Toxicity/Pathogenicity

(885.4240)

A 21-day static renewal study was conducted to determine the toxicity and/or 

pathogenicity of Streptomyces Strain K61 spores to Daphnia magna. A control group 

was tested against four treatment groups, including a maximum nominal dose 

exposure of 1.0 x 106 CFU/mL, low and median doses of 104and 105 CFU/mL, plus a 

dose of 1.0 x 106 CFU/mL of heat-killed spores. No significant differences (P>0.05) 

were found between the control and the exposure levels for reproduction and time to 

first brood. All of the offspring produced during the study appeared normal. Mean 

survival was 100% for control and low level concentration, 75% for the middle 

concentration, and 0% for the high concentration and killed spore treatment. Mortality 

from killed spore treatments has been reported from previous studies, and is thought to 

be caused by creating a toxic environment through the autoclaving process. A day 21 

EC50 was calculated to be approximately 190 mg/L (1.9 x 105 CFU/mL). Daphnid 

growth was found to be significantly affected at the middle concentration (1 x 105

CFU/mL). The NOAEC was found to be 1.0 x 104 CFU/mL, the LOAEC was 1.0 x 

105 CFU/mL and the MATC was found to be 3.2 x 10

4 CFU/mL. This indicates that 

Streptomyces Strain K61 is practically non-toxic to Daphnia magna. The study fulfils 

EPA Guideline requirements for an acute toxicity test for an aquatic invertebrate.

Classification: Acceptable

418211-22

Nontarget Plant Testing

(885.4300)

Not required for Streptomyces Strain K61 because the microbial pest control agent is 

not taxonomically related to known plant pathogens (refer to test note #7 of 40 CFR § 

158. 2150(e)).

Not applicable

Honey Bee Testing

(885.4380)

Nontarget Insect 

Testing

(885.4340)

Three treatment levels, representing 240, 760 and 2400 ppm at a specific activity of 

9.8 x 108cfu/g of diet, were tested along with an attenuated control and a negative 

control. Two replicates were tested at each concentration with 25 bees per replicate. 

Mortalities occurred in both of the control groups (negative and attenuated) and in all 

3 of the treatment groups. The mortalities in the negative and attenuated control 

groups were 30% and 62%, respectively, while those in the 240, 760, and 2400 ppm 

concentrations averaged 20%, 26% and 28%, respectively. The pattern of mortality 

was not found to be dose responsive and did not appear to be treatment related. The 

LC50 was determined to be greater than 2400 ppm and the NOAEC was 2400 ppm, 

which was the highest concentration tested. Due to nonspecific mortality in the 

controls, however, the study is considered supplemental. The results were reliable 

enough to indicate that MYCOSTOP®is not toxic or pathogenic to the honey bee. 

This study also satisfies the data requirements for nontarget insect testing (OCSPP 

Guideline 885.4340). 

Classification: Supplemental

418211-23

Tiers II, III, and IV

Not required for Streptomyces Strain K61 based on the results of the nontarget toxicity/pathogenicity Tier I studies, which did not 

demonstrate adverse hazards.