Sheep faeces placed on a pasture in New Zealand in February and April were
retrieved at intervals up to 28 days and examined for fungi that parasitise
nematodes (nematophagous fungi).
Monacrosporium haptotylum,
Harposporium bysmatosporum,
H. helicoides and a Nematoctonus
sp. were present, respectively, in 37, 22, 13 and 8% of 283 samples
retrieved in February and from 29, 14, 11 and 15% of 200 samples
retrieved in April. Fungi entered faeces rapidly, being present in 35 and
54% of samples retrieved after 3 days in February and April,
respectively. The ability of migrating soil nematodes to carry fungal
propagules from soil into faeces was assessed in 2 laboratory experiments.
Sheep faeces separated from soil by filters that allowed passage of both
nematodes and fungi was colonised by H. helicoides more
frequently than faeces on filters that excluded nematodes, indicating
nematodes were vectors. However,
Arthrobotrys oligospora,
M. haptotylum and A. brochopaga
occurred in faeces independently of filter type, indicating that these species
grew into faeces. Two laboratory experiments examined the ability of
nematophagous fungi, when inoculated into sheep faeces containing eggs of the
gastro-intestinal nematode parasite Trichostrongylus colubriformis to reduce
the number that developed to third-stage larvae.
Monacrosporium gephyropagum,
A. cladodes, A. conoides and
A. oligospora reduced the number of third-stage larvae
that emerged by 54–91% (P<0.05) in
comparison to a control; however, M. haptotylum and
H. bysmatosporum were ineffective. In a second
experiment, several species of nematophagous fungi reduced the number of
third-stage larvae that emerged by 41–96%
(P<0.05) in comparison to a control, while others had
no effect.
Predatory activity of Arthrobotrys oligospora and Duddingtonia flagrans on pre-parasitic larval stages of cyathostominae under different constant temperatures
