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Bacillus thuringiensis - Fact Sheet 9/86

Name of Chemical:  Bacillus thuringiensis (B.T.)
Reason for Issuance:  Registration Standard
Date Issued:  September 1986
Fact Sheet Number:  93

             1. DESCRIPTION OF MICROBIAL

Taxonomic.Name:  Bacillus thuringiensis varieties kurstaki, israelensis,
and aizawai

Common Name:  Bacillus thuringiensis (B.t.)

Trade Names:  (for B.t. variety kurstaki) Dipel, Thuricid, Bactospeine,
Leptox, Novabac, Bug Time, Cekubacillina and Attack, Agritrol, Bakthane,
Larvatrol, and Biotrol BPB.
              (for B.t. variety israelensis) Bactimos, Teknar, and Vectobac
              (for B.t. variety aizawai) Certan
EPA/OPP Chemical Code (Shaughnessy) Number:  6401
Chemical Abstracts Service (CAS) Number:  None
Year of Initial Registration:  1961
Pesticide Type:  Bacterial Insecticide
Microbial Family:  Bacillaceae
U.S. and Foreign Producers:  Abbott Laboratories; Biochem Products; Reuter
Laboratories, Incorporated. A Sandoz Company; Zoecon Company Inc.

            2. USE PATTERNS AND FORMULATIONS

Application site:  See Table 1 for application sites.

Pests Controlled:  See EPA's Compendium Index for targeted pests, which can
be found attached to the B.t. Registration Standard.  The Registration
Standard may be obtained from the information Services Branch, Room 236,
CM#2, 1921 Jefferson Davis Highway, Arlington, Va. 22202.  Telephone (703)
557-2805

Table 1.  Application Sites and Pests Controlled by B.t. Varieties
Kurstaki, Israelensis, and Aizawai

   Application site                           Pests Controlled
__________________________________________________________________________

B.t. variety kurstaki

  TERRESTIAL FOOD CROPS

Alfalfa, Artichoke, Avocado, Banana,            See EPA's Compendium
Beans, Beets, Blueberries, Caneberries,         Index for targeted
Carrots, Celery, Citrus Fruits, Clover,         pests.
Cole Crops, Corn, Cotton, Cranberry,
Cucumber, Currants, Dandelion, Eggplant,
Endive, Forage Crops, Garlic, Grapes, Hops,
Horseradish, Kiwi Fruit, Lentils, Lettuce,
Melons, Mint, Nut Crops, Nut Trees, Okra,
Onions, Parsley, Parsnip, Pastures, Peanuts,
Peas, Pepper, Pome Fruits, Potatoes, Pumpkin,
Radish, Rangeland, Rice, Rutabaga, Safflower,
Salsify, Small Fruits, Small Grains, Soybeans,
Spinach, Squash, Stone Fruit, Strawberry,
Sugar Beets, Suqar Maple, Sunflower, Sweet potato,
Swiss Chard, Tobacco, Tomato, Tropical Fruits,

Walnut, and Watermelons

  TERRESTRIAL NON-FOOD CROPS

Forest Trees,                                  .See EPA's Compendium
Ornamental Flowering Plants                     Index for targeted
(including nursery stock and                    pests.
chrysamthemum), Ornamental herbaceous Plants
(including nursery stock), Ornamental and/or
Shade Trees, and Ornamental Turf

  GREENHOUSE FOOD

Beans, Beets, Carrots, Celery, Cole Crops,       See EPA's Compendiuim
Cucumbers, Eggplant, Lentils, Lettuce, Melon,    Index for targeted
Onions, Parsley, Peas, Peppers, Potato,          pests.
Radish, Spinach, Squash, Sweet Potato, and
Tomato

Table 1.  Application Sites and Pests Controlled by B.t. Varieties Kurstaki,
Israelensis, and Aizawai (Cont'd)

   Application Site                              Pests Controlled
___________________________________________________________________________

B.t, variety kurstaki

  INDOOR STORAGE

Grain Crops,                                     See Compendium
Peanuts, Seed and Pod Vegetables,                Index for targeted
Soybeans, Sunflower, and                         pests.
Tobacco

B.t. variety israelensis

  DOMESTIC OUTDOOR

Domestic Dwellings                               Mosquito (larvae)

  AQUATIC FOOD CROPS (Agricultural Crops)

Pasture                                          Mosquito (larvae)
Rice                                             Mosquito (larvae)

  AQUATIC NON-FOOD

Brackish water                                   Mosquito (larvae)

Catch basins, storm water retention areas,       Mosquito (larvae)
temporary accumulations of water

Mangrove swamps, salt marshes, tidal water       Mosquito (larvae)

Drainage systems                                 Mosquito (larvae)

Irrigation systems                               Mosquito (larvae)

Intermittently flooded areas, flood water,       Mosquito (larvae)
woodland pools, standing water

Lakes, ponds                                     Mosquito (larvae)

Sewaqe waste lagoons                             Mosquito (larvae)

Streams                                          Black flies (larvae)

Table 1.  Application Sites and Pests Controlled by B.t. Varieties Kurstaki,1
Israelensis, and Aizawai (Cont'd)

   Application Site                              Pests Controlled
___________________________________________________________________________

B.t. variety aizawai

  INDOOR (Agricultural Premises and Equipment)

Honeycomb (empty)                               Greater wax month (larvae)

Use Patterns and Formulations (continued)

Types and Methods of Application:

   (for B.t. variety kurstaki) Aerial and ground.
   (for B.t. variety israelensis) Aerial and ground.
   (for B.t. variety aizawai) Hand sprayer.

Application Rates:

   (for B.t. variety kurstaki) 0.001 to 0.25 pounds per acre.
   (for B.t. variety israelensis) 0.001 to 10 pounds per acre.
   (for B.t. variety aizawai) 0.5 to 2.0 ounces per square inch
      (indoor use).

Types of Formulations:

   (for B.t. variety kurstaki) Stabilized suspension; wettable powder;
      dust base; dust; bait; and flowable concentrate.
   (for B.t. variety israelensis) Wettable powder; flowable concentrate;
      and granulars.
   (for B.t. variety aizawai) Water-dispersible liquid concentrate.

                        3. SCIENCE FINDINGS

Summary Science Statement:

     The available information that has been reviewed suggests that B.t. is
potentially safer than many synthetic chemical pesticides currently used
for the same applications.

     B.t. a bacterial insecticide, has no known toxic or pathogenic effect
in humans or other mammals.  The Agency, has reviewed and evaluated all
available data, including those data submitted to the Agency in support of
the registration of B.t. products, as well as data from published
literature, concerning B.t. varieties kurstaki, aizawai and israelensis.
All three of these varieties of B.t. are covered by this fact sheet.

     Adequate data were available to assess the acute oral, inhalation,
dermal, toxicological, and other biological effects of this bacterial
agent.  The Agency's review of these data determined that no data gaps
exist in the toxicology data base and no major environmental mammalian
safety concerns (except for certain endangered species of Lepidoptera) were
identified.  However, data gaps were found to exist in the ecological
effects data base.  Based on the available data the Agency's review and
evaluation did not identify substantive concerns regarding unreasonable
adverse effects of the currently registered varieties of B.t.  Therefore,
the Agency concluded that the use of B.t. products can be continued and
that B.t.products may be used, as presently registered, with only minor
precautionary labeling changes and additional nontarget organism data being
required.

Microbial characteristics:

     Except as indicated, the description of the characteristics of B.t.
that follows pertains to all three varieties of B.t. set forth above.  B.t.
is a naturally occurring, gram positive, rod-shaped, spore-forming
bacterium, which is pathogenic to the larvae of a number of insects
species, especially lepidoptera, when ingested by the larvae.  B.t. variety
israelensis is also a pathogen to the larvae of some insects in the order
Diptera, e.g., mosquitoes and midges.  The vegetative cells of B.t. are
approximately 1 micrometer (um) in width and 5 um in length and are motile.
Propulsion of the vegetative cell is by peritrichous flagella.  A
distinctive feature of B.t. is the presence of a protein crystal composed
of protoxin.  Under the appropriate alkaline conditions and in the presence
of proteolytic enzymes, the protoxin is activated to endotoxin(s) (e.g.
delta-endotoxin) which forms in addition to an endospore within the
bacterial cell wall.  The delta-endotoxin has been shown to be harmless to
mammals and is released only under a highly alkaline environment, such as
that in the midgut of lepidopteran larvae. In addition to delta-endotoxin,
some strains of B. t. produce another toxin called beta-exotoxin (also
known as thuringiensin) which is secreted externally to the cell wall, and
which has a broad range of toxicity to insects. Currently registered B.t.
products comply with 40 CFR 180.1011 which requires that any B.t. product
exempt from the requirements of a tolerance must contain no measurable
amounts of beta-exotoxin, as determined by the fly larvae bioassay.

     The Agency has determined that bacterial cell-free B.t. beta-exotoxin
is a chemical pesticide, and will be treated as such. There are no products
registered with beta-exotoxin. Such products will require separate toxicity
testing prior to consideration for registration. If any B.t. products with
beta-exotoxin are registered, they will be dealt with under a separate
standard when appropriate.

B. Toxicological Characteristics

     B.t. was one of the first insect pathogens registered in the United
States and as such was required to undergo an extremely rigorous mammalian
toxicity/infectivity evaluation. Much of the testing program for B.t. was
based on the testing requirements for conventional chemical pesticides, and
the data base required for the original registration of B.t. was more
extensive than that currently required by 40 CFR Part 158 (c). Accordingly,
no mammalian toxicity/infectivity data gaps exist for B.t. Many acute
toxicity/pathogenicity studies with various varieties of B.t. have been
conducted using several routes of administration in rats, rabbits, and
guinea pigs. Among the various studies reviewed, the highest dose tested
was 6.7 x 10(11) spores per animal. There were no significant adverse
effects associated with these studies.

Data Requirements

1. Product Analysis:

     In all cases product identity and disclosure requirements have been
satisfied; however, since the microbial pesticide was registered, Subpart M
Biochemical/Microbial pesticide Guidelines have been promulgated, and since
more detailed information is needed all product analysis data are required
to be submitted in order to complete the requirement of this standard as
set forth in 40 CFR Part 158 Section (c) for microbial and biochemical
pesticides.

2. Residue Data

     No data are required in this area, because no residue of concern have
been designated. Additionally, an exemption from the requirement of a
tolerance for all raw and processed agricultural commodities has been
established.  The exemption is partially based on the condition that beta-
extoxin is not present in B.t. formulations.

3. Toxicology Data

     Since B.t. was one of the first insect pathogens to be registered in
the United States, it was required to undergo an extremely rigorous
mammalian toxicity-infectivity evaluation program. The regimen was more
stringent than that currently required by 40 CFR Part 158 Section (c). Much
of the testing program was based on the testing requirements for generating
conventional chemical pesticide data. Consequently there are no mammalian
toxicity/infectivity data gaps for B.t. A wide variety of mammalian
toxicity/pathogenicity studies have been conducted with B.t. kurstaki,
israelensis, and aizawai using several routes of administration in rats,
rabbits, and guinea pigs. Among the studies reviewed the highest dose
tested was 6.7 x 10(11) spores per animal.These data indicate that there
are marginal, if any deleterious effects cause by the use of products
containing B.t. Most of the data is on B.t. varieties kurstaki and
lsraelensis.

     The following toxicology studies are examples of the types of
toxicology data that were submitted in support of the current B.t.
registrations.

Bacillus thurinqiensis Toxicity/Infectivity Profile(1)

                   Animal
Variety            Tested       Route              Effect
___________________________________________________________________________

Kurstaki           rabbit       oral           No acute oral infectivity;

                                               LD50 > or = to 2.0 x 10(9)
                                               spores/animal

Kurstaki           rat          oral           No acute oral infectivity;
                                               LD50 > or = to 2.67 grams/
                                               kilogram

Israelensis        rat          innoculation   No acute oral infectivity;
                                               LD50 > or = to 6.9 x 10(7)
                                               spores/kilogram

Israelensis        rat          oral           No acute oral infectivity;
                                               LD50 > or = to 1.2 x 10(11)
                                               spores/kilogram

Kurstaki           rat          oral           No acute oral infectivity;
                                               LD50 > or = to 4.7 x 10(11)
                                               spores/kilogram

Kurstaki           rat          innoculation   No acute oral infectivity;
                                               LD50 > or = to 3.4 x 10(11)
                                               spores/kilogram

Israelensis        rabbit       innoculation   No acute oral infectivity;
                                               LD50 > or = to 6.28 grams/
                                               kilogram

Kurstaki           rat          innoculation   No acute oral infectivity;
                                               LD50 > or = to 4.6 x 10(11)
                                               spores/kilogram

Kurstaki           rat          inhalation     No acute oral infectivity;
                                               8 x 10(11) spores/animal

Kurstaki           rabbit       innoculation   No intraperitoneal infec-
                                               tivity; LD50 > or = to
                                               6.9 x 10(7) spores/kilogram

Kurstaki           rabbit       innoculation   No corneal opacity, conjunc-
                                               tival redness reversible
                                               with 7 days dose: 6.9 x
                                               10(7) spores/animal

(1) Based on data as reported. No attempt was made to convert units or
iterpret end points.

Bacillus thurinqiensis Toxicity/Infectivity Profile(1)

                   Animal
Variety            Tested       Route               Effect
___________________________________________________________________________

Kurstaki           human        oral           No toxicity/infectivity;
                                               dose:  1 gm/day for three
                                               consecutive days

Kurstaki           guinea piq   innoculation   No sensitizations; severity
                                               index = 0.2 to 0.3

Kurstaki           rat          innoculation   No toxic or virulent
                                               effects; LD50 > 5 gm/kg

Israelensis        rat          Intracerebral  A dose of 10(7) organisms
                                (ic)           killed the test animals;
                                innoculation   death was probably due to
                                               the massive i.c. inoculum
                                               and not any infective
                                               process; most of the animals
                                               died within 24 hours.

(1) Based on data as reported. No attempt was made to convert units or
interpret end points.

                           Ecological Effects

     Numerous studies submitted to the Agency and literature articles have
been reviewed in an attempt to assess the potential of B.t. products for
adverse.ecological effects. In general, the data indicate a lack of adverse
effects on non-target insect species, fish, plants, mammals, and humans.
However, most of the studies lack key elements of information which
preclude definitive conclusions. The Agency has determined that the data
reviewed fully satisfy three of the data requirements prescribed by 40 CFR
Part 158 (d), and partially satisfy two of those requirements. All other
requirements are data gaps.

Specifically, the data requirements are in the following categories:

l) B.t. variety israelensis

   a) Avian oral study (154-16)

   b) An avian injection study (154-17)

   c) Freshwater aquatic invertebrate (154-20) (requirements have been
      partially met).

   d) Estuarine and marine animal toxicity data (154-21)

2) B.t. variety kurstaki

   a) The avian oral (154-16) requirement has been partially satisfied;

   b) No acceptable data are available to meet avian injection (154-17),
      freshwater fish 154-19), freshwater aquatic invertebrate (154-20),
      nontarget plant (154-22), or insects (154-23,24) data requirements.

3) B.t. variety aizawai

   a) No data are required to complete registration of B.t. variety
      aizawai, because it is for indoor use.

4) Endangered species

     At this time the Agency does not have sufficient information to
complete its assessment of the potential impact of certain uses of B.t. on
endangered and/or threatened species of Lepidoptera. The Department of
Interior's Office of Endangered Species (OES) is being consulted on this
issue, and the Agency is deferring a final assessment of hazard to these
endangered species pending completion of the consultation with OES. In the
interim, users of B.t. are encouraged to consult local officials
responsible for protecting endangered species or the nearest EPA Regional
Office before using B.t. products in the following counties where
susceptible endangered species of Lepidoptera are known to be present.

     County, State               Species of Concern
     _____________               __________________

Los Angeles, California          El Segundo blue butterfly
                                 Palos Verde blue butterfly

Contra Costa, California         Lange's metalmark butterfly

Mendocino, California            Lotis blue butterfly

San Francisco California         Mission blue butterfly

San Mateo, California            Mission blue butterfly
                                 San Bruno elfin butterfly

Monterey, California             Smith's blue butterfly

Kern, California                 Kern primrose sphinx moth

Dade, Florida                    Schaus swallowtail butterfly

Monroe, Florida                  Schaus swallowtail butterfly

Lane, Oregon                     Oregon silverspot butterfly

Pacific, Washington              Oregon silverspot butterfly

Tillamook, Washington            Oregon silverspot butterfly

         Tolerance Exemption Assessment 40 CFR Section 180.1011

     An exemption from the requirement of a tolerance has been established
for residues of B.t. in or on all raw agricultural commodities in
accordance with the provisions of 40 CFR Section 180.1011, when applied
after harvest. This exemption remains in force for B.t. products covered by
this standard.

              Summary of Regulatory Position and Rationale:

     The Agency is requiring product analysis data on all currently
registered B.t. products, and all new products proposed for registration,
in accordance with 40 CFR Part 158 (a). The reason for this is that product
analysis data is product specific. Furthermore, available product analysis
data for registered products date back to 1961, when B.t. was first
registered as a microbial pesticide. At that time analytical techniques
were much less sophisticated compared to current techniques. Therefore the
old data lack essential information which is now available by current
techniques. An itemized list of the Product Analysis Data requirements can
be found in Table A, B, and C of the Standard.

     The Agency is requiring ecological effects data as prescribed at 40
CFR Part 158 (d). An itemized list of the data requirements applicable to
B.t. varieties kurstaki, israelensis, and aizawai can be found in Table A
on pages 58, 59, 60, of the standard.

     Most of the ecological effects data submitted to the Agency lack key
elements and/or information which precludes making definitive conclusions.
Therefore, these data are required as outlined earlier.

Endangered Species:

     The OES has not identified any concerns about B.t. products with
respect to endangered species. If any concerns are are identified in the
future the Registration Standard will be updated accordingly.

Contact Person at EPA:

Arturo E. Castillo
Acting Product Manager (PM-17)
Registration Division (T5-767C)
Office of Pesticide Programs
Environmental Protection Agency
401 M Street, S.W.
Washington, D. C. 204060.