How is the pesticide Bacillus thuringiensis kurstaki (B.t.k.) used to control gypsy moths?
The Washington State Department of Agriculture uses a pesticide spray known as Bacillus thuringiensis kurstaki (B.t.k.) for gypsy moth control B.t.k. is a naturally occurring bacteria found in soil. An inactive, or spore, form of the bacteria is approved by the Environmental Protection Agency for use as a pesticide to control gypsy moth. It is commonly used by organic gardeners to control pests, and is approved for use on more than 200 food and grain crops in the United States. B.t.k. is harmful to moths and butterflies only at their caterpillar stage of development. Spores are activated in the stomachs of caterpillars that eat vegetation sprayed with B.t.k. causing the catepillars to die in 7 to 10 days. The commercial B.t.k. spray used by the Department of Agriculture is called Foray®. In addition to B.t.k.,the product also contains ingredients to make it stick to plant leaves, and has residues of food crops and preservatives that are approved for use on food. When diluted for ground
