Officials said drug agents, racing Northern California marijuana growers to their own fields, have seized $460 million worth so far this harvest season. On Tuesday alone, they destroyed more than $10 million worth statewide, officials of the multi-agency Campaign Against Marijuana Planting said. The haul this season of 135,302 plants represents 90% of the "documented" marijuana crops in California--crops they know about, campaign officials said. One agent estimated that more than half the total illicit crop has been located and is thus in the "documented" category. Because of the pressure, CAMP officials say outlaw growers are becoming more sophisticated in concealing fields of the potent weed, which is the state's No. 1 cash crop. However, agents insist that they are winning the war against pot production, and claim that it is a measure of their success that growers are planting in increasingly remote areas.