FRESNO, Calif. (AP) - Pollutants carried in runoff from farms affect the water supply of more than 20 million Californians and taint prime fishing grounds across the state, according to a recent report. The pollution is the byproduct of pesticide use, but it doesn't have to be, said Gary Wolff, chief economist at the Oakland-based Pacific Institute, an environmental research group. Wolff, who wrote the institute's "Investing in Clean Agriculture" report, said educating farmers is key to cleaning the state's water. But he acknowledges that education doesn't come cheap, so Wolff's study suggests raising taxes on pesticides to pay for...