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Btk – Bacterial Insecticide Fact Sheet

Actual name  -
  • Bacillus thuringiensis var.  kurstaki  or Btk
Type of Product -
  • Biological pesticide, a type of pesticide derived from natural materials such as plants or bacteria.   Bt is a naturally occurring soil bacteria.
How Btk works -
  • Gypsy moth caterpillars must eat Btk for it to be effictive because it interferes with the digestion system.  The active ingredient is a crystal protein toxin formed by the bacteria.  The alkaline gut and enzimes that only caterpillars have activate the toxin that kills the cells lining, stopping the caterpillar from feeding and dies withing 2 to 5 days.  This alkaline condition is not present in the stomachs of humans,birds, or fish and other animals.
How Btk is made -
  • Btk is cultured using water and nutrients such as sugars and starches, in a fermenting process similar to brewing beer.  The final product contains almost all water, the leftover growth medium, carbohydrates, inert ingredients that are approved as food additives, and the active ingredient.
What Btk affects -
  • Different strains of Bt affect different insects.    Btk has no effect on humans, pets birds, fish, livrstock, honey bees or other wildlife.  Btk is so specific to only certain moth and butterflies that is is an approved control product for use by certified  organic gardners.
  • As with the application of any control product, people, pets or domestic animals with known respiratory ailments or other health concerns my wish to avoid exposure by staying indoors during the spray operation and until the Btk product is dry (usually a few hours).
  • The Btk applied in a spray does not multiply or accumulate inthe enviroment.
Application rate -
  • 1/2 Gallon per Acre
Application timing -
  • After all caterpillars have hatched.
  • Most effective when caterpillars are young and have a gut lining thin enough for the Btk toxin to punch holes in it.  Once the larvae have gotten larger than 5/8-inch long, they are rather difficult to kill.
  • Mid—to late –May or early June
Why we use Btk -
  • Breaks down in sunlight within seven days
  • Highly effective: nearly 80% mortality of gypsy moth caterpillars in treated areas
  • Highly effective with high gypsy moth caterpillar populations
  • Readily available
  • Known to be toxic to feeding caterpillars of moths and butterflies and is safe to humans, birds, fish, pets, beneficial insects and other non-target organisms
FORAY 48B ORMI CERTIFICATE -  Foray 48B OMRI Certificate – This product may be used in certified organic production. 
FORAY 48B ORGANIC LABEL -  Foray 48B US Organic Label – For commercial Forestry and wide area pest tretment – Aerial Application
FORAY 48B MSDS-  Foray 48B Organic Material Safety Data Sheet (MSDS)