UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

 OFFICE OF CHEMICAL SAFETY 

 AND POLLUTION PREVENTION 

September 22, 2010

SUBJECT: Environmental Risk Assessment for a FIFRA Section 3 Registration for 

Trichoderma asperellum, strain T34 for Control of Fungal Root Disease in 

Ornamental and Carnation Plants in Greenhouses [EPA File No. 87301-

R]; Decision # 425700, DP Barcode # 373656, Submission # 865549

MEMORANDUM

FROM: Shannon Borges, Biologist /signed/

Microbial Pesticides Branch

Biopesticides and Pollution Prevention Division, 7511P

THROUGH: Zigfridas Vaituzis, Senior Scientist /signed/

Microbial Pesticides Branch

Biopesticides and Pollution Prevention Division, 7511P

TO: Anna Gross, Regulatory Action Leader 

Microbial Pesticides Branch

Biopesticides and Pollution Prevention Division, 7511P

Biocontrol Technologies, S.L. has applied for a FIFRA Section 3 registration for Trichoderma 

asperellum strain T34 use on ornamental and carnation plants in greenhouses for control of 

fungal root diseases. This memorandum contains the ecological risk assessment for this 

proposed registration.

I. Introduction

Trichoderma asperellum strain T34 is an active ingredient proposed for a FIFRA Section 3 

registration for use on ornamental and carnation plants in greenhouses. T. asperellum strain T34 

is intended to control fungal diseases within the rhizosphere of these plants resulting from 

pathogenic microorganisms, primarily Fusarium oxysporum. The primary mode of fungicidal 

action of T. asperellum strain T34 is competition with pathogenic fungi for space and nutrients

through colonization of plant root zones and construction of a physical barrier to infection, 

parasitization of pathogenic fungi, and induction of plant resistance responses. The proposed 

end-use product containing T. asperellum strain T34 is applied via treatment of potting media 

before planting, treatment of the potting media surface at or after planting either through a spray 

or through an irrigation system, or root dip. If needed, reapplication is suggested every 2-3 

months or prior to a situation that might cause increased risk of disease.
II. Environmental Exposure

The proposed label directs the user to apply T. asperellum strain T34 at a rate of 10g/m3 of 

potting media prior to planting, at a rate of 0.5 g per m2 surface area immediately after planting,

or at a rate of 5 g per 1000 1-L pots containing potting medium. These maximum application

rates result in concentrations of 6.6 x 103 – 1.0 x 104 cfu T. asperellum strain T34/mL potting 

medium. Applications via root dip are expected to result in much lower concentrations within 

the potting media, since the T. asperellum strain T34 will be localized at the roots. Trichoderma

spp. concentrations in soil have been reported at 103 – 106 cfu/g (Harman et al. 2004, Leandro et 

al. 2007, Liu et al. 2008), and T. asperellum strain T34 was found to persist at 104 cfu/mL 

potting medium at four months after application, based on data submitted by the registrant in 

MRID 48067407. Therefore, the population size of T. asperellum strain T34 is not expected to 

significantly increase beyond that resulting from the proposed application rates and will not be 

larger than that of Trichoderma spp. naturally found in soil. In the event that treated potting 

media were disposed of outdoors, nontarget organisms would not be exposed to Trichoderma 

concentrations above naturally occurring levels. Nonetheless, exposure in outdoor environments 

is expected to be very limited, since the product is intended for use indoors in greenhouses. 

Therefore, exposure to nontarget organisms is expected to be negligible, if it occurs at all.

III. Environmental Effects Data

Table 1 provides the status of the data requirements for the technical grade active ingredient 

(TGAI). The data waiver rationales used for this assessment are summarized within the

environmental risk conclusions in the section below, and a Data Evaluation Record of the 

rationale submitted and its supporting documentation is attached. The information provided is 

sufficient to satisfy the Tier I nontarget organism data requirements and for nontarget organism 

risk assessment for the TGAI. Further testing of nontarget organisms at higher tier levels is not 

required. 

Table 1. Status of data required to comply with nontarget organism data requirements published

in 40 CFR § 158.2150 for support of the registration of Trichoderma asperellum Strain T34. 

Data Requirement OPPTS 

Guideline No.

Results Summary and 

Classification

MRID No.

• Avian oral 

toxicity/pathogenicity

• Freshwater fish 

toxicity/pathogenicity 

• Freshwater 

invertebrate 

toxicity/pathogenicity

• Estuarine/marine fish 

and invertebrate testing 

• Nontarget insect 

testing

• Honey bee testing

885.4050

885.4200

885.4240

885.4280

885.4340

885.4380

Data waiver rationale provides 

sufficient information to determine 

that toxicity/pathogenicity to avian 

wildlife, wild mammals, 

freshwater and marine/estuarine 

fish and invertebrates, honey bees, 

and nontarget insects is not 

expected as a result of the 

proposed label uses. 

Classification: Acceptable

47068102
Data Requirement OPPTS 

Guideline No.

Results Summary and 

Classification

MRID No.

Wild mammal 

toxicity/pathogenicity

885.4150 Studies required by 40 CFR § 

158.2140 are adequate and 

appropriate for assessment of 

hazards to wild mammals. Acute 

oral toxicity/pathogenicity testing 

indicated no significant adverse 

effects to laboratory rats dosed at 

1.1 x 108

Classification: Acceptable for 

wild mammal risk assessment

cfu/animal after 21. 

48067401

• Avian inhalation 

toxicity/pathogenicity

• Nontarget plant 

testing

885.4100

885.4300

Not required – active ingredient is 

not related to known avian or plant 

pathogens

N/A

IV. Environmental Risk Conclusions

A. Terrestrial animals and plants

The proposed registration limits use to indoor environments within greenhouses and the 

proposed maximum application use rates result in concentrations that are not above measured 

concentrations of Trichoderma spp. naturally occurring in soil. Therefore, exposure in the 

terrestrial environment is expected to be negligible, if it occurs at all. 

The registrant submitted data waiver rationale to fulfill the requirement of acute oral and avian 

inhalation toxicity/pathogenicity studies. Data from an optimum growth temperature study was 

also submitted, and showed that T. asperellum strain T34 does not grow at normal avian body 

temperatures. Based on this information, exposure of birds to T. asperellum strain T34 is not 

expected to result in adverse effects on birds and risk to birds resulting from the proposed use of 

T. asperellum strain T34 is not anticipated.

Acute oral toxicity/pathogenicity testing indicated no significant adverse effects to laboratory 

rats dosed at 1.1 x 108 cfu/animal after 21 days (MRID 48067401). There is no reason that tests 

on laboratory mammals are not representative of the potential hazard to wild mammals in this 

case; therefore, based on this information, adverse effects on wild mammals are not expected 

from exposure to T. asperellum strain T34. Since the proposed use is also expected to minimize 

exposure, risk to wild mammals resulting from the proposed registration of T. asperellum strain 

T34 is not anticipated.

The registrant submitted information on the toxicity/pathogenicity data for several insect species 

exposed to T. harzianum (the former classification of some strains of T. asperellum) and T. 

gamsii. While these data cannot be used directly to determine the potential hazard of this 

particular strain of T. asperellum, they do provide some evidence of the lack of effects of 
Trichoderma spp. on insects. The Agency has previously expressed concern over the potential 

hazard of T. harzianum strain T39 (USEPA 2000), and several papers have shown adverse 

effects of this related fungus on nontarget insects, particularly coleopteran species (Cardoza et al. 

2006, Jassim et al. 1990, Shakeri and Foster 2006). Nontarget insect testing has not been 

performed for T. asperellum strain T34; however, because exposure is expected to be minimal

risk to nontarget insects is not anticipated. Future expansion of the uses of T. asperellum strain 

T34 may require additional nontarget insect toxicity/pathogenicity testing.

As with other nontarget insects, the Agency had previously expressed concerns for potential 

effects on honey bees for a related Trichoderma spp., T. harzianum strain T39 (USEPA 2000); 

however, data were subsequently submitted to show that adverse effects are not expected from 

exposure to that strain. Trichoderma spp. are widely understood to present no potential adverse 

effects to honey bees, which is supported by data submitted by the registrant showing lack of 

effects of honey bees and bumble bees (Bombus terrestris) following exposure to several 

Trichoderma spp. Therefore, BPPD concludes that T. asperellum strain T34 will not pose risk to 

honey bees as a result of the proposed labeled uses.

Studies on the toxicity/pathogenicity of T. asperellum strain T34 to terrestrial plants were not 

required because T. asperellum, and other Trichoderma spp., are not taxonomically related to 

any known plant pathogens. Therefore, adverse effects to plants are not expected as a result of 

the proposed uses of T. asperellum strain T34, and risk is not anticipated.

B. Freshwater and marine/estuarine fish and invertebrates

The registrant presented extensive rationale to show that exposure of T. asperellum strain T34 in 

aquatic environments would be negligible, if it occurred at all, and would have no effects on fish 

or aquatic invertebrates if it were to reach surface waters. Data from a study was submitted to 

show that at four months after the last application of T. asperellum strain T34 to potted plants, 

leachate from the pots contains 102 cfu/mL of T. asperellum strain T34, which is less than the 

amount of Trichoderma spp. found naturally in soil. Therefore, spillage onto greenhouse soil 

and outdoor disposal of treated potting material would not increase the amount of Trichoderma

spp. normally found in soil or in any runoff. Incidents such as these are expected to have 

negligible contribution to exposure. The registrant presented additional data from public 

literature to show that if T. asperellum strain T34 were to reach surface waters, it would be 

unable to proliferate and would be unlikely to survive. Based on the information provided, 

exposure to aquatic environments is expected to be negligible and adverse effects in these 

environments are not expected. Therefore, BPPD concludes that the proposed use of T. 

asperellum strain T34 will not result in risk of adverse effects to fish and aquatic invertebrates in 

freshwater and marine environments. 

Studies on the toxicity/pathogenicity of T. asperellum strain T34 to aquatic plants were not 

required because T. asperellum, and other Trichoderma spp., are not taxonomically related to 

any known plant pathogens and exposure in these environments is not expected. Therefore, 

adverse effects to aquatic plants are not expected as a result of the proposed uses of T. 

asperellum strain T34, and risk is not anticipated.
C. Risk to Federally Listed Threatened and Endangered Species

Since EPA has determined that no effects are anticipated for any non-target species exposed to T. 

asperellum strain T34 as a result of the proposed labeled applications, effects to threatened and 

endangered species and their designated critical habitats are also not expected. Therefore, a “No 

Effect” determination is made for direct and indirect effects to listed species and their designated 

critical habitats resulting from the registered uses of T. asperellum strain T34, as labeled.

V. Environmental Assessment Summary

The Agency has performed an environmental risk assessment based on data waiver rationale and 

open literature studies, and has determined that the proposed uses of Trichoderma asperellum 

strain T34 do not pose risk to nontarget organisms. T. asperellum strain T34 is a naturally 

occurring strain of T. asperellum. This and other Trichoderma species are ubiquitous and occur 

widely in soils in concentrations ranging up to106 cfu/g dry soil. Based on the concentration of 

the active ingredient in the end use product and the application instructions on the label, 

concentrations in treated potting media result in concentrations of 6.6 x 103 – 1.0 x 104 cfu T. 

asperellum strain T34/mL. T. asperellum strain T34 is intended for inoculation of potting media 

and root treatment of carnation and other ornamental plants, and is restricted to application in 

greenhouses only. Due to the nature of the application method, exposure to terrestrial nontarget 

organisms is expected to be very low, if not nonexistent. The use of T. asperellum strain T34 as 

proposed is not expected to significantly increase the amount of Trichoderma spp. beyond levels 

that are already present in soils. 

The registrant has submitted data waiver rationale to satisfy data requirements for nontarget 

organism risk assessment with the TGAI. Submitted data, data waiver rationale, and a search by 

BPPD of several literature databases provides sufficient information to determine that 

toxicity/pathogenicity to wild mammals, avian wildlife, freshwater and marine/estuarine 

vertebrates and invertebrates, honey bees, nontarget insects, and terrestrial and aquatic plants is 

not expected from the proposed label uses. As a result, a “No Effect” determination is also made 

for direct and indirect effects to listed species and their designated critical habitats resulting from 

the registered uses of T. asperellum strain T34, as labeled.

The information provided is sufficient to satisfy the Tier I nontarget organism data requirements 

and for ecological risk assessment for the active ingredient. Further testing of nontarget 

organisms at higher tier levels is not required. 

VI. References

Cardoza, Y.J., K.D. Klepzig, and K.F. Raffa. 2006. Bacteria in oral secretions of an endophytic 

insect inhibit antagonistic fungi. Ecol. Ent. 31:636-645.

Harman, G.E., C.R. Howell, A. Viterbo, I. Chet, and M. Lorito. 2004. Trichoderma species –

opportunistic, avirulent plant symbionts. Nature Reviews 2:43-56. MRID 48067407.
Jassim, H.K., H.A. Foster, and C.P. Fairhurst. 1990. Biological control of Dutch elm disease: 

larvicidal activity of Trichoderma harzianum, T. polystrum and Scydalidium lignicola, 

Scolytus scolytus and S. multistriatus reared in artificial culture. Ann. Appl. Biol. 117:187-

196.

Leandro, L. F. S., T. Guzman, L. M. Ferguson, G. E. Fernandez, and F. J. Louws. 2007. 

Population dynamics of Trichoderma in fumigated and compost-amended soil and on 

strawberry roots. Applied Soil Ecology 35:237-246.

Liu, B., D. Glenn, and K. Buckley. 2008. Trichoderma communities in soils from organic, 

sustainable, and conventional farms, and their relation with Southern blight of tomato. 

Soil Biology and Biochemistry 40:1124-1136.

Shakeri, J. and H.A. Foster. 2006. Proteolytic activity and antibiotic production by Trichoderma 

harzianum in relation to pathogenicity to insects. Enzyme and Micro. Tech. 40:961-968.

U.S. Environmental Protection Agency (USEPA). 2000. Trichoderma harzianum Rifai strain T39 (119200) Fact Sheet. Available at:

http://www.epa.gov/pesticides/biopesticides/ingredients/tech_docs/tech_119200.htm.