The occurrence of entomopathogenic fungi in soils from mid-field woodlots and adjacent small-scale arable fields
The aim of this study was to compare the species composition and the intensity of entomopathogenic fungi occurrence in the soil from mid-field woodlots and adjacent small farmlands. The study material consisted of soil samples taken from a mid-field woodlot and an adjacent small-scale arable field in three different localities in the vicinity of Siedlce. Entomopathogenic fungi were isolated from soil using two methods: the insect bait method and the selective medium. The comparative study showed that the soil from mid-field woodlots was characterized by a richer species composition of entomopathogenic fungi than of adjacent arable fields. A total of six fungal species representing the anamorphs of Hypocreales (Ascomycota) were isolated from the soil collected from mid-field woodlots: <em>B. bassiana, B. brongniartii, M. anisopliae, M. flavoviride, I. farinosa</em> and <em>I. fumosorosea</em>. The presence of only three species was reported in the farmland soil: <em>B. bassiana, M. anisopliae</em> and <em>I. fumosorosea</em>. This fact confirms the important role of semi-natural habitats as a source of biodiversity of entomopathogenic fungi in agricultural landscape. It was found that entomopathogenic fungi together formed more colony-forming units in the soil from arable fields than that of neighbouring mid-field woodlots. <em>B. bassiana</em> was the species of fungus which infected more bait insect larvae and formed significantly more colony-forming units (CFU) in the soil from mid-field woodlots than that of farmland in the localities studied, whereas the trend was the opposite in the case of <em>I. fumosorosea</em> and <em>M. anisopliae</em>. Given the presence of entomopathogenic fungi in the farmland soil in the three test places together, it was found that <em>I. fumosorosea</em> was dominant in the soil from the two arable fields, where this fungus infected more <em>G. mellenella</em> larvae and formed significantly more CFUs than the other species of fungi. <em>M. anisopliae</em> was the second most frequently isolated farmland species.