SACRAMENTO, Calif. (AP) – Researchers and federal authorities are finding what they say is an alarming increase in the use of a powerful pesticide at illegal marijuana farms hidden on public land in California. They’re finding the pesticide residue in marijuana illegally grown in California but mostly destined for Midwestern and Eastern states. Researcher Mourad Gabriel tells The Associated Press that his team found the highly toxic pesticide Carbofuran at 72 percent of grow sites last year, up from 15 percent in 2012. Nearly a third of pot plants tested positive for the pesticide. Gabriel says the pesticide is so powerful that less than a teaspoon can kill a 300-pound bear. Federal and state authorities are announcing Tuesday that they will target the illegal grows with $2.5 million in federal money.