Ovicidal and larvicidal effect of Bacillus thuringiensis var. kurstaki on free living stages of trichostrongylid nematodes is being surveyed using a bioassay in which 48-72 hours culture broth (>90% of spores) of the bacteria is added to fresh feces or feces incubated previously for 24 or 48 hours. Treated feces were incubated at 27°C for seven days after which the larvae were recovered through baermanization and formalized for a later counting. Ovicidal effect was observed in two strains and larvacidal effect in four strains.
Bacillus thuringiensis; biological control; Haemonchus contortus; gastrointestinal nematodes; ruminants
