The occurrence of entomopathogenic fungi in soils from mid-field woodlots and adjacent small-scale arable fields

Abstract

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: B. bassiana, B. brongniartii, M. anisopliae, M. flavoviride, I. farinosa and I. fumosorosea. The presence of only three species was reported in the farmland soil: B. bassiana, M. anisopliae and I. fumosorosea. 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. B. bassiana 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 I. fumosorosea and M. anisopliae. Given the presence of entomopathogenic fungi in the farmland soil in the three test places together, it was found that I. fumosorosea was dominant in the soil from the two arable fields, where this fungus infected more G. mellenella larvae and formed significantly more CFUs than the other species of fungi. M. anisopliae was the second most frequently isolated farmland species.