USE OF NEMATODE TRAPPING FUNGI AS A BIOLOGICAL CONTROL IN GRAZING LIVESTOCK

Authors: Soder, Kathy; HOLDEN, LISA - PENN STATE UNIV

Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2004
Publication Date: 11/18/2004
Citation: Soder, K.J., Holden, L.A. 0204. Review: Use of nematode-trapping fungi as a biological control in grazing livestock. Professional Animal Scientist. 21:30-37.

Interpretive Summary: Increased use of chemicals to control internal parasites in grazing livestock has led to issues such as parasite resistance to chemicals, environmental concerns, and concerns of chemical residues in animal products. Specific fungi have been identified as a potential biological control of certain internal parasites (nematodes) by 'trapping' and consuming those nematodes as they hatch in manure pats. Our objectives were to evaluate the efficacy of these nematode-trapping fungi in grazing heifers, to summarize completed work, to explore the potential for further research in the United States, and to determine the fungi's potential efficacy and acceptance as a biological control for parasitic nematodes in grazing livestock. Use of nematode-trapping fungi in the control of internal parasites will probably not replace traditional therapy of highly infected animals, but may be incorporated together with other options into integrated pest management systems to provide sustainable nematode control of livestock with minimal negative environmental impact. Additional research, particularly in the United States, is necessary to further elucidate the environmental conditions, dosage rates, and administration routes, such as the use of continuous release devices.

Technical Abstract: Threat of anthelmintic resistant 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. Results in other countries have shown that D. flagrans survives passage through the gastro-intestinal tract, and is able to trap and destroy free-living stages of parasitic nematodes in manure. 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 free-roaming pigs. Additional work is necessary in the United States to evaluate the efficacy of D. flagrans as a biological control for parasitic nematodes, particularly under the varied climatic conditions found throughout the country.