Biopesticides -- the word is a contraction of biological pesticides -- are derived from natural substances like bacteria and plants. In that way, they differ substantially from pesticides that are manufactured entirely through the interaction of man made chemicals. Biopesticides were developed to provide a less toxic means of protecting crops from diseases and insects that would otherwise destroy them. Such toxins associated with the use of man made chemicals created dangerously contaminated food and water supplies for millions of people around the world, including here in the United States. Instead of preventing disease and invasive insects like beetles from destroying crops through the use of chemicals. biopesticides use natural biological interactions to protect agriculture.
The best source of information on biopesticides is probably the U.S. Environmental Protection Agency's website, found at www.epa.gov/pesticides/biopesticides/whatarebiopesticides.htm.
The companies that develop and manufacture biopesticides are represesented by an industry coalition called Biopesticide Industry Alliance, the website for which is at www.biopesticideindustryalliance.org.
A more technically advanced source of information is at the Journal of Biopesticides' website www.jbiopest.com.