Sort by
Wpływ zasolenia podłoża hodowlanego na wzrost grzybów entomopatogeniczych z rodzajów Beauveria i Metarhizium

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.

Open Access
Relevant
Wpływ metody inokulacji roślin kukurydzy patogenami bakteryjnymi na powstawanie i rozwój objawów chorobowych

The basis of phytopathological diagnostics are Koch’s postulates, the fulfillment of which allows determining whether the examined microorganism is the cause of a given disease. The third of these postulates specifies that inoculation of a healthy host plant with a pure culture of the putative pathogen must result in the induction of disease symptoms similar or the same to those occurring in natural con¬ditions. To meet Koch’s third postulate, a pathogenicity test result is required, and incorrect interpretation may lead to rejection of cor¬rect results. Many years of research on bacteriosis of crop plants, including corn, have shown that the symptoms of the disease resulting from inoculation with the tested strain of bacteria may vary, depending on the inoculation method used and the incubation conditions of the inoculated plants. The conducted research determined the impact of various methods of inoculating corn plants with selected strains of pathogenic bacteria isolated from diseased corn plants on the occurrence and development of disease symptoms. These strains belonged to the species Pectobacterium carotovorum subsp. carotovorum, Dickeya zeae, Pantoea ananatis, Pantoea agglomerans and Enterobacter cloaceae subsp. dissolvens. It was observed that the symptoms of the disease caused by the inoculation methods used dif¬fer from the symptoms observed in natural conditions. Moreover, regardless of the species affiliation of the tested bacterial strains, the observed symptoms were similar within a given inoculation method. Also, regardless of the species affiliation of the tested strain, incuba¬tion of inoculated plants in a culture chamber with optimal conditions for the development of the disease resulted in the acceleration of symptoms and disease development.

Open Access
Relevant
Wpływ bionawozów zawierających substancje humusowe na wzrost grzybów z rodzaju Beauveria i Metarhizium w warunkach 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.

Open Access
Relevant