In-Vitro Sensitivity of Infective Larvae of Oesophagostomum Species to Nematophagous Fungi

Abstract

Two experimental assays (A and B) evaluated the action of conidia of the nematophagous fungi Duddingtonia flagrans (AC001), Monacrosporium sinense (SF53) and Artrhobotrys robusta (I-31) against infective larvae (L3) of Oesophagostomum spp in 2% water-agar (2%WA) medium and coprocultures.  The first assay consisted of three groups of 1000 Oesophagostomum L3 treated with 1000 conidia of isolates AC001, SF53 and I-31 and control without fungus plated in 2% WA. In the second assay, 1000 conidia of the same isolates were added to 20g of faeces and incubated at 26°C for 8 days. The L3 no predate were recovered after this period fungal treatment. There was no variation in the predatory capacity among the tested fungal isolates (p>0.01) during the experimental period of seven days. There were significant reductions (p<0.01) of 94.4%, 92.9%, and 88.3% in the means of Oesophagostomum L3 recovered from the treatments with isolates AC001, SF53 and I- 31, respectively, when compared to the control treatment. Second assay also showed statistical differences (p<0.01) between the means of recovered L3 in the treated groups and the control, with the following percent reductions:  75.3% (AC001), 63.7% (SF53) 63.3% (I-31). In this study, the three isolates of predatory fungi D.  flagrans (AC001), M. sinense (SF53) and A.  robusta (I-31) were efficient in the in vitro capture and destruction of Oesophagostomum L3 and are potential biological control agents of this nematode.