Frequently Asked Question

Bacillis Thuringiensis var. kustaki (known as 'Bt') is a naturally occurring microbe commonly found in soil. Bt has been registered by the US Environmental Protection Agency since 1961 for use to control insect pests on food, forage crops and forests. It is frequently used by organic farmers, commercial landscapers and home gardeners for its effectiveness, low risk, and selectivity. A specific Bt strain called ‘kurstaki’ is formulated as an insecticide that kills spongy moth and other caterpillars. Spongy moth caterpillars ingest Bt when they eat host leaf tissue sprayed with it. Soon after, caterpillars stop feeding and die a short time later.