EPA's Records Disposition Schedule PEST 361 Scientific Data Reviews HED Records Center - File R153710 - Page 1 of 4 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON. D.C. 20460 

OFFICE OF 

./ 

i 

PESl"ICIOES AND TOXIC SUBSl"ANCES 

:~8IVlORANDUN 

SUBJECT: "New chemical screen"; Toxicology Branch screen for 

reg:hstration of the fungus Gliocladium virens for greenhouse 

ornamental and greenhouse foo~rop-u8es~----

TO: L. Schnaubelt (PIVl-21) 

Registration Division 

- ,J 

Roy D, Sjoblad, Ph.D. .If. /J,;1 J?/~.:d:.,. Microbiologist, SMSS, Toxicology Branch ~ 

~'ROM: 

THROUGH: Reto Engler, 

Chief, SMSS 

Ph.D. 

MPCA: Gliocladium virens 

~/ -. 8/lb(si 

, 

Pesticide Chemical Code: .28900-8 

Product names: WRC-GL-21, and WRC-AP-1 Caswell #: 

EPA Reg.H: 11688-U and l1688-G Pesticide petition #: 8F3659 

BaCKground: 

W,R. Grace & Co. wishes to register the fungus Gliocladium 

virens strain GL-21 (from the USDA culture collection), Application 

is made for registration of the product designated WRC-GL-21 for 

manufacturing use, and application for registration of the 

product designated as WRC-AP-1 is for use on ornamentals and food 

crops in the greenhouse. The Registrant requests a waiver for the 

requirement for the following studies, and for the following reasons: 

Acute dermal toxicity (Tier I): because the proposed labeling requires 

hand protection, and product ingredients are not known to be dermal 

toxicants, and testing with laboratory animals shows that the active 

ingredient is not pathogenic. 

Prima~ eye irritation/infectivity study (Tier I): because proposed 

labeling requires eye protection while handling, and the active 

ingredient is not pathogenic to laboratory animals. 
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Hypersensitivity study: because the active lngredient is not 

pathogenic to laboratory animals and no hypersensitive incidents 

have been observed over a two-year period among researchers 

working with the active ingredient_ 

The Registrant submItted for the screen an acute oral, and 

an acute pulmonary, and an acute intravenous study to support 

registration of the manufacturing-use and formulated products_ 

On April 6, 1988 representatives of EPA met with represenatatives 

of W. R. Grace & Co. to discuss data reQuirements for registration 

of Gliocladium virens for use as a fungicide in the greenhouse, 

The formulated product is to be applied by blending with soil or 

soil-less growing medium, or by surface application to soil 

followed by blending in with the top one-inch of soil medium 

prior to planting. A sample of the "prill" (pelleted) formulation 

of the fungus was brought to the meeting by the Registrant, Each 

spherical pellet was approximately several millimeters in diameter. 

For the purposes of Registration of Gliocladium virens for 

the proposed greenhouse uses, the Toxicology Branch recommended 

the foIl owi ng: 

An acute oral infectivity/toxicity study (according to the 

most recently available SubdiviSion M guideline revisIons) 

using the pelleted form of the fungus. 

An acute ulmonar infectivit /toxicit stud (also according 

to recent SubdiviSion M guidelines with the spore form of 

the fungus, since the large diameter of the formulated product 

prohibited use of the formulated product via pulmonary exposure, 

and It appeared that pulmonary exposure to the spore form of the 

fungus would be the most likely. However, if pulmonary exposure 

to significant amounts of the vegetative form is likely, then 

this form of the fungus may also have to be tested. 'rhe 

objective of the study is to provide information on the toxicity 

and clearance from test animals of the spore form of the 

active ingredient. 

An acute intravenous infectivit /toxicit stud (also 

according to recent reVised guidelines with the vegetative 

mycelial form of the fungus, to provide data on the infectivity 

and pathogeniCity of the active ingredient, 

It was indicated to the Registrant that immune response studies 

currently are no longer being reqUired, and that reporting of hypersensitivity incidents is sufficient to replace the formerly reQuired 

hypersensitivity study. In addition, the eye irritation study 

(infectivity portion of study no longer required) need not be done 

provided workers' eyes are protected from exposure to aerosols 

of the product, Also, dermal irritation studies are not included 

as reQuired in the revised SubdiVision M guidelines, however, dermal 
EPA's Records Disposition Schedule PEST 361 Scientific Data Reviews HED Records Center - File R153710 - Page 3 of 4 

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toxicity studies are required, unless appropriate justification for 

their waiver is provided. 

10xico]ogy Branch conclusions from screen of data~kage: 

The Registrant has submitted an acute ora] infectivity/toxicity 

study with the pelleted form of the product, and an acute pulmonary 

infectivity/toxicity study with the fungal spores, and an acute 

intravenous infectivity/toxicity study with the mycelial form of the 

fungus_ A written report stated that no hypersensitivity reactions 

were observed in eight researchers working with the fungus for up 

to two years, 

The request for waiving the eye irritation study on the 

basis of wearing of protective eye coverings during periods of 

potential exposure is adequate for waiving the study for the 

intended registration uses. The request for waiving the dermal 

toxicity study on the basis that the product ingredients are 

not known to be toxic and on the basis that the active ingredient 

is not pathogenic for humans are not sufficient reasons to grant a 

waiver of this study. However, the requirement for wearing of 

gloves during handling of the material coupled with the large 

pellet size of the product, and with its intended use via soil 

incorporation are sufficient for not requiring this study for the 

intended greenhouse uses. Thus, the acute oral, acute pulmonary, 

and acute intravenous studies proVided are sufficient in 

number to represent Tier I data requirements. Of course, this 

screen does not address the question of whether the three submitted 

studies provide acceptable data, and, thus whether Tier II studies 

will be required. This will be done when the studies are officially 

reviewed by the Toxicology Branch. 

A descriptive taxonomic characterization of the active 

fungal ingredient as Gliocladium virens was provided; however, 

it was not clear to this reviewer which characteristics allow 

for separation of this fungus from Trichoderma virens and Trichoderma 

viride, two fungi for which "_._Gliocladium virens has often been 

misidentified." Each batch of the fungus is monitored for several 

recognized mammalian pathogenic bacteria, and also for gliotoxin 

(assay method limits of detection are >10 mg/l), which is indicated 

as a potential impurity of "toxicologi~ Significance." 

A preliminary study on the effect that temperature has on 

limiting growth of the fungus showed that the active ingredient can 

grow at 35C· but not at 37C· or at 40C·- The request for an exemption 

from tolerance for Gliocladium virens can be addressed subsequent 

to review of the above studies. 

Recommendation: The studies/information submitted are sufficient 

for the Toxicology Branch to recommend that the products containing 

G. virens pass the screen. However, the Registrant should provide 

a more detailed taxonomic characterization of the test fungus, and 

a more detailed description of the toxicological properties of 

gliotoxin and on methods to determine its presence in product batches; 

and, also should provide more detailed studies evaluating the potential 

for fungal growth at 37C·- The latter would be helpful if. data from 

the submitted mammalian toxicology studles are equlvocal wlth respect 

to infectivity in test animals, 
EPA's Records Disposition Schedule PEST 361 Scientific Data Reviews HED Records Center - File R153710 - Page 4 of 4 

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Chemical: 

HED File Code: 

Memo Date: 

File ID: 

Accession #: 

• 

R153710 

Gliocladium virens G-21 

PC Code: 

129000 

41500 BPPD Tox/Chem 

8/16/1988 

00000000 

000-00-9003 

HED Records Reference Center 

111112007 

• 

•