Population development and activities of plant-parasitic nematodes in soil are limited by a number of antagonistic organisms. Bacteria and other prokaryotes can parasitize nematodes directly (Pasteuria penetrans) or may kill or inhibit nematodes through production of toxins, metabolites, or enzymes that destroy eggs or other life stages of the animals. Many rhizosphere bacteria are antagonistic to nematodes. Nematode trapping fungi such as species of Arthrobotrys, Catenaria, Oligospora, among others, form mycelial structures with which they can immobilize and destroy nematodes. Other fungi invade the nematode body forming endospores (Myzocytium spp., Haptoglossa spp.), while others (Gliocladium spp., Paecilomyces spp., Verticillium spp.) penetrate and destroy eggs, females, or cysts. Other soil organisms that are antagonistic or predatory of nematodes include microarthropods, nematodes (orders Dorylaimida and Mononchida), and protozoans. Efforts to inoculate soil with microbial speci
