Efficacy ofClonostachys roseaandDuddingtonia flagransin Reducing theHaemonchus contortusInfective Larvae

Abstract

The biocontrol is proven effective in reducing in vitro and in situ free-living stages of major gastrointestinal helminths, allowing progress in reducing losses by parasitism, maximizing production, and productivity. This study aimed at evaluating the predatory activity of fungal isolates ofDuddingtonia flagransandClonostachys roseaspecies and its association on infective larvae (L3) ofH. contortusin microplots formed by grasses and maintained in a protected environment. All groups were added with 10 mL of an aqueous suspension with 618H. contortusL3approximately. Group 1 was used as control and only received the infective larvae. Groups 2 and 3 receivedD. flagranschlamydospores andC. roseaconidia at doses of 5 × 106. Group 4 received the combination of 5 × 106D. flagranschlamydospores + 5 × 106C. roseaconidia.D. flagransandC. roseashowed nematicidal effectiveness reducing by 91.5 and 88.9%, respectively, the population ofH. contortusL3. However, when used in combination efficiency decreased to 74.5% predation ofH. contortusL3. These results demonstrate the need for further studies to determine the existence of additive effects, synergistic or antagonistic, between these species.