Parasitic Roundworms (IMAGE) University of Bern Caption Parasitic roundworms (entomopathogenic nematodes) are used to control root-feeding insect pests. A new study now shows that under the right conditions, nematodes can develop resistance against plant defense substances and can thereby increase their efficiency as biological control agents. Image: Heterorhabditis bacteriophora in the infective juvenile stage. Credit Anouk Guyer, University of Bern 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.