The northern root-knot nematode (NRKN) is a major pathogen of vegetables grown in New York. Crop growth in heavily infested fields is often patchy and uneven. Carrots become forked, stubby, hairy, and develop galls on the fine roots and on the carrots themselves. Infected onions exhibit stunting, delayed maturity, larger necks and smaller bulbs. Onion roots show small galls or root- thickening and extensive branching. Lettuce plants become stunted and produce small, loose and often unmarketable heads. Distinct and large galls are formed on infected lettuce roots.