Predacious soil microorganisms

In the soil habitat various forms of microbial predation are known. Protozoa prey on one another and also on bacteria, yeasts, algae, and some even on nematodes. The latter and other small animals also feed on bacteria. 

Some myxobacteria kill eubacteria and other microorganisms with a secreted antibiotic, lyse the dead cells with an extracellular enzyme mixture and utilize the soluble products. 

A number of fungi belonging to the Hyphomycetes and Zygomycetes trap soil nematodes, soil amoebae, and sometimes rotifers and subsequently invade and devour them. The members of the Zoopagales shed sticky conidia which adhere to the prey, usually an amoeba or other small soil animal, and put out germ tubes which penetrate into the body where a small thallus is formed. They are probably obligate predators [1]. 

More than 50 species of nematode-trapping fungi are known. Many are Deuteromycetes of the order Moniliales. The genera most commonly represented are Arthrobotrys, Dactylaria, Dactylella, and Trichothecium. They 

Initial attempts to exploit predaceous fungi for the biological control of a nematode-caused disease, root-knot of pineapple, were made just prior to World War II in Hawai. Perhaps, under certain conditions, the activities of nematode-trapping fungi can be directed against nematode parasites that are of economic significance. 

---