THE POTENTIAL OF NEMATOPHAGOUS FUNGI TO CONTROL THE FREE-LIVING STAGES OF NEMATODE PARASITES OF SHEEP - COMPARISON BETWEEN AUSTRALIAN ISOLATES OF ARTHROBOTRYS SPP. AND DUDDINGTONIA FLAGRANS

Nine isolates of Duddingtonia flagrans and eight isolates of Arthrobot rys spp. which originated from a field survey for the presence of nema tophagous fungi in fresh dung of livestock in Australia were used in t his study, Comparisons were made between the ability of the different isolates to survive gut passage and subsequently reduce infective larv al numbers in sheep faeces. Fungal spores (conidia and/or chlamydospor es) were administered orally to sheep in doses ranging from 1 x 10(5) to 4.5 x 10(6) spores. There was no apparent consistent survival of Ar throbotrys spp,, whereas D. flagrans showed excellent survival capacit y which resulted in profound reductions in Trichostrongylus colubrifor mis larval numbers in culture. This provides clear evidence that D. fl agrans is an ideal candidate as a potential biological control agent f or nematode parasites of sheep. (C) 1997 Elsevier Science B.V.