The effect salinity culture medium on the growth of entomopathogenic fungi of Beauveria and Metarhizium genera

The aim of the research was to determine the effect of increasing NaCl concentration (one of the important stress factors for crop plants) on the growth of entomopathogenic fungi of the genus Beauveria and Metarhizium in vitro. The influence of 1, 3, 5 and 15% NaCl con¬centration on the growth of colonies of four selected species of fungi Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae and Metarhizium flavoviride was examined in laboratory conditions. Test concentrations were added to Sabouraud’s culture medium (SDA). Colony growth observations were made every 5 days until day 20, measuring the colony diameter in mm. The conducted research showed that the NaCl concentrations used in the experiment had a differential effect on the growth of colonies of the tested species of entomopathogenic fungi of the genus Beauveria and Metarhizium. A slight salinity of the culture medium (1% NaCl concentration), regardless of the date of observation, increased the growth of B. bassiana and B. brongniartii colonies and limited the growth of M. fla¬voviride. On the 20th day of observation, 3% salinity statistically significantly stimulated the growth of the B. bassiana and M. flavoviride strains. A higher concentration of NaCl limited the growth of the tested strains, with M. flavoviride showing the greatest resistance, which may indicate it as a species with a relatively high potential for resistance to salinity. 15% salinity completely inhibited the growth of all entomopathogenic fungi tested.