In vitro assessment of two species of nematophagous fungi (Arthrobotrys oligospora and Arthrobotrys flagrans) to control the development of infective cyathostome larvae from naturally infected horses.

The ability of two species of nematophagous fungi, Arthrobotrys oligospora and Arthrobotrys flagrans (syn. Trichothecium flagrans, Duddingtonia flagrans), to control the development of infective larvae in feces from naturally infected horses was assessed in vitro. The horses were from a farm where it had been previously established that cyathostomes accounted for 100% of the strongyle egg output. The feces from these naturally infected horses were mixed with spores of each fungal species at four concentrations: 0 (control), 1, 10, and 100 spores per egg. Five replicates for each group were incubated for 8 days. Infective larvae were harvested using a Baermann technique and counted. The percentage reduction in infective cyathostome larvae was calculated for each fungal concentration compared to controls. A fungal concentration of 1 spore per egg resulted in 40.5% and 32.1% reduction for A. oligospora and A. flagrans, respectively. A concentration of 10 spores per egg resulted in 87.4% and 90.5% reduction, while 100 spores per egg resulted in 95.8% and 93.9% reduction for A. oligospora and A. flagrans, respectively.