ABSTRACT
The natural enemies of entomogenous nematodes, as well as those of nematodes in general, can be grouped into predators, parasites, and pathogens. These agents are not only effective in nature, but also in the laboratory when attempts are being made to culture entomogenous nematodes. Mermithid nematodes are especially susceptible to fungal infections under laboratory conditions, and such infections may seriously hamper mass production of these parasites. A number of invertebrates prey on nematodes in general and will undoubtedly attack the free-living stages of many entomogenous nematodes, depending on their size. Most predaceous arthropods are probably capable of attacking various stages of entomogenous nematodes. Bacteria often cause problems in the storage of entomogenous nematodes in water by depleting the available supplies of oxygen. A wide range of fungi attack nematodes and the literature on nematophagous fungi is very extensive.
