Use of Nematode-Trapping Fungi as a Biological Control in Grazing Livestock

Potential for anthelmintic resistance as well as increasing concerns about chemical residues in livestock products and the environment pose serious threats to the future of chemo-therapeutic control of animal parasitic nematodes in grazing livestock. Nematophagous fungi, such as Duddingtonia flagrans, show promise as a potential biological control of parasitic nematodes in grazing animals. Our objective was to examine the scientific literature regarding the use of nematophagous fungi as a biological control of parasitic nematodes, to summarize completed work, and to explore the potential for further research on the potential efficacy and acceptance as a biological control for parasitic nematodes in grazing livestock. Research to date has shown that D. flagrans survives passage through the gastrointestinal tract and is able to trap and destroy free-living stages of parasitic nematodes in manure, reducing fecal egg counts in grazing livestock by 55 to 100% over the course of a grazing season. The D. flagrans fungus could be incorporated as part of a feed supplement or incorporated into feed blocks for grazing ruminants and horses and for freeroaming pigs. Additional work is necessary in the U.S. to evaluate the efficacy of D. flagrans as a biological control for parasitic nematodes, particularly under the varied climatic conditions found throughout the country.