What type of pesticide is Bt?

Bt, or Bacillus thuringiensis, is classified as a selective pesticide because it specifically targets certain pests while having minimal impact on non-target organisms. These pests are typically larvae of some insects, particularly those of the orders Lepidoptera, Coleoptera, and Diptera. Because Bt is derived from a natural bacterium, it works by producing proteins that are toxic to these specific groups of insects once ingested. This selectivity is significant in integrated pest management strategies, as it allows for effective control of harmful pests without detrimental effects on beneficial insects, wildlife, or the environment.

In contrast, broad-spectrum pesticides are designed to affect a wide range of pests, potentially disrupting entire ecosystems. Non-selective pesticides would eliminate most or all pests indiscriminately. Chemical pesticides refer to a broad category, which may include both selective and non-selective chemicals; Bt is biological rather than strictly chemical. Thus, its specificity in targeting pests solidifies its classification as a selective pesticide.