Efficacy of two isolated of the nematode-trapping fungus Duddingtonia flagrans against Dictyocaulus viviparus larvae on pasture

FERNÁNDEZ, ALICIA SILVINA; LARSEN, MICHAEL; NANSEN, PETER; GRØNVOLD, JØRN; HENRIKSEN, SVAN AAGE; BJØRN, HENRIK; WOLSTRUP, JENS

Copenhagen

Conferencia; 17th International Conference of the World Association for the Advancement of Veterinary Parasitology; 1999

Danish Centre for Experimental Parasitology

A laboratory dose-titration assay demonstrated that the isolates CI3 and Troll A of Duddingtonia flagrans significantly reduced the numbers of Dictyocaulus viviparus and Cooperia oncophora L3 in faecal cultures. Two plot trials were carried out to confirm this effect under natural conditions. Artificial faecal pats containing D. viviparus L1 and C. oncophora eggs plus one of the two fungal isolates were deposited twice on pasture plots and the herbage around the pats was sampled periodically. The pats were recovered after one month to determine the faecal degradation. The herbage sampling showed a reduced transmission of gastrointestinal as well as lungworm larvae (77 to 100% and 34 ti 80%, respectively) around pats containing the fungus. The transmission of C. oncophora larvae, but not D. viviparus, was clearly affected by the climatic conditions during both trials. Determinations of wet and dry weight plus organic matter content of the pats showed no differences between the fungus-treated and non-treated control pats, indicating that the addition of the fungus did not affect the faecal degradation. The present study is the first report of the activity of nematode-trapping fungi against D. viviparus under natural conditions. These results call for further research in this area.