Bacillus thuringiensis (Bt) Kurstaki and Israelensis strains
Pesticide Classification
__ Herbicide __ Fungicide
__Bactericide
_X Insecticide/Miticide
__ Molluscicide __ Repellent
Properties Properties Properties
__ Selective
__ Non-selective

__ Pre-emergent
__ Post-emergent

__ Systemic
__ Contact
__ Broad Spectrum
__ Specific

__ Systemic
__ Non-systemic

__ Protectant
__ Eradicant
__ Synthetic
_X Biological
__ Oil
__ Soap
__ Botanical
__ Other
__ Broad-spectrum
_X Specific

__ Systemic
_X Non-systemic

__ Contact poison
_X Stomach poison
__ Other

Common Brand Names:

Israelensis strain (BTi) - Bonide Mosquito Beater WSP
Israelensis strain (BTi) - Gardens Alive Knock Out Gnats Granules (fungus gnat larvae control)
Israelensis strain (BTi) - Gnatrol (fungus gnat larvae control)
Israelensis strain (BTi) - Summit Mosquito Bits
Israelensis strain (BTi) - Summit Mosquito Dunks
Kurstaki strain (BTk) - Bonide Bacillus thuringiensis
Kurstaki strain (BTk) - Bonide Thuringiegsis (BT) Concentrate
Kurstaki strain (BTk) - Ferti-lome Dipel Dust
Kurstaki strain (BTk) - Hi Yield Thuricide Concentrate
Kurstaki strain (BTk) - Safer Brand Caterpillar Killer
Kurstaki strain (BTk) - Safer Garden Dust w/Bt

Chemical Action and Usages: Bacillus thuringiensis is a naturally occurring soil bacterium disease that is fatal to the larva stage of certain insects. There are a number of strains of Bt, but the most commonly used are the kurstaki strain (Btk) and the israelensis strain (Bti). Each strain is specific to the insect larvae it controls.

The kurstaki strain controls the larva stage (caterpillars) of certain moths and butterflies such as tomato and tobacco hornworm, cabbage worms, loopers, leaf rollers, bagworms, gypsy moths, tent caterpillar, fall webworm and others. Ingestion of the bacterium paralyzes the digestive system of the insect, and it stops feeding within hours. Bt affected insects usually die within several days of ingesting the bacteria. Since Btk is most effective on young, heavily feeding larvae, insect populations must be monitored to insure that the targeted insect is in the proper stage for optimum control. Btk will not control the larva stage of sawflies. Btk may be applied up to the day of harvest on a variety of food crops. This biological/microbial insecticide is available as a dust or in a liquid concentrate form.

The israelensis strain is used to control mosquito larvae by placing it into the standing water of mosquito breeding sites. Ingestion of the bacterium paralyzes the larvae and they stop feeding and die, sometimes within 24 hours. Fungus gnat larvae control with the israelensis strain is obtained by drenching the soil of the infected plants with the bacterium.

Cautions/Instructions: Read the label carefully of the brand and formulation you have selected. Apply the product according to the instructions on the label. Btk is toxic to the larvae of many butterflies. Btk will not control the larvae of sawflies, so proper identification is important. Liquid formulations of Btk have a shorter shelf life than the dusts and are best used within two years of purchase. Btk should not be applied to standing water and Bti should not be applied to water reservoirs intended for human consumption.

Toxicity: Very low toxicity to humans, pets, birds, bees and fish.