Root-Knot Nematode (IMAGE) University of New Hampshire Caption The root-knot nematode is a parasitic roundworm that can infect about 2,000 plants and is one of the three most damaging parasitic nematodes to agricultural crops worldwide. Credit UNH Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.