Effect of zinc and copper on cultivable populations of soil fungi with special reference to entomopathogenic fungi

The effect of copper and zinc on cultivable soil fungi populations was in-vestigated in a laboratory experiment. Samples of four different soils (ar-able sandy soil and loam clay; forest sandy soil and forest peat) were col-lected from sites located in Vilnius district, Lithuania. Metals ’ effect was elaborated by addition of metal salts (CuSO4 and ZnSO4) at appropriate concentrations into the growth medium (Czapek’s agar) and evaluating cul-tivable fungi abundance and species diversity changes. Zinc or copper salt was added to the medium after its sterilization; zinc concentration varied from 0.05 to 0.20 M (by 0.05 M concentration range) and copper concent-ration – from 0.5 to 3.0 mM (by 0.15 mM concentration range). At elevated metal salt concentrations, the abundance of cultivable fungi decreased with a marked elimination of some fungi species as compared with a control medium (without metal addition) fungi cultures. Irrespective of a fungi community structure in different type soils, Cu was a stronger inhibitor of soil fungi population abundance than Zn, however, both metals showed a comparable effect on the fungi species diversity. The most resistant fungi belonged to common insect pathogens (Beuveria bassiana, Metarhizium anisopliae, Lecanicillium lecanii and Isaria spp.), which dominated com-prising up to 90 % of all recovered from the soils isolates, due to the metal salt concentration.