Differential in vitro pathogenicity of predatory fungi of the genus Monacrosporium for phytonematodes, free-living nematodes and parasitic nematodes of cattle

In vitro tests were carried out on the pathogenicity of nine isolates of th e predatory fungi of the genus Monacrosporium (5 M. sinense isolates, 3 M. appendiculatum and 1 M. thaumasium isolate) for a phytonematode (second sta ge juveniles from Meloidogyne incognito, race 3), a free-living nematode (P anagrellus spp), and two gastrointestinal parasitic nematodes of cattle (in fective larvae of Cooperia punctata and Haemonchus placei). A suspension co ntaining 2,000 nematodes from each species was added to Petri dishes contai ning fungi and grown on 2% water-agar medium at 25 degrees C in the dark fo r up to 7 days. The dishes were examined every other day for 7 days and pre dation-free nematodes were counted. The results showed that the free-living nematodes, Panagrellus spp, were the most susceptible (P<0.05), followed b y the phytonematode M. incognita, while the controls were greater than or e qual to 98.5% viable. However, a variable susceptibility of the nematodes t o different fungi was observed. This indicates that the use of predatory fu ngi for the environmental control of nematodes will be limited by the multi plicity of nematodes in the environment and their differential susceptibili ty to fungal isolates of the same genus.