The effect of biofertilizers containing humic substances on the growth of Beauveria and Metarhizium fungi in vitro

Biofertilizers, including biofertilizers, seem to be one of the best ways to increase or maintain the current rate of food production, while ensuring the stability of the natural environment. The aim of the study was to determine the effect of selected biofertilizers containing humic substances on the in vitro growth of entomopathogenic fungi of the genus Beauveria and Metarhizium in the context of their combined use in plant cultivation and protection. The effect of biofertilizers Rosahumus, Liqhumus 18 and BNB on the growth of colonies of four selected species of entomopathogenic fungi Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae and Metarhizium flavoviride was tested in laboratory conditions. Biofertilizers were added to the Sabourauda (SDA) culture medium at the recommended field dose. Colony growth observations were made every 5 days until day 20th by measuring colony diameters in mm. The conducted research showed that the biofertilizers containing humic substances used in the experiment acted in a different way on the growth of insecticidal fungi of the genus Beauveria and Metarhizium. Among the tested biofertilizers, only the BNB preparation showed an inhibitory effect on all the tested isolates. The greatest stimulating effect of the tested preparations was found in relation to the fungi B. bassiana and M. flavoviride, while the most sensitive species turned out to be M. anisopliae.