A Glenville, Minnesota man is arrested in Nebraska after a traffic stop leads to the discovery of a mobile marijuana crop.It happened Wednesday morning near Henderson, Nebraska; after a state trooper pulled over 56-year-old David Herman of Glenville after receiving reports of a motorist driving erratically.A search of the vehicle turned up seven big jars containing 18 packages of medical marijuana, and a rubberized storage bin in the trunk containing marijuana plants, a fan, thermometer and fluorescent light.Herman was arrested on suspicion of driving under the influence of drugs, marijuana manufacture and possession.