Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XIX
Written by Ana-Cristina FĂTU, Mihaela-Monica DINU, Ana-Maria ANDREI
The entomopathogenic fungus Beauveria brongniartii Sacc. (Petch) is the most important natural enemy of Melolontha melolontha L. Three strains of B. brongniartii isolated from natural diseased M. melolontha larvae were tested in order to assess the effects of temperature and relative humidity on conidial germination, the most important factors during the initialization of infection process. Conidial germination was examined at temperatures ranging from 4° to 33°C, on PDA medium. The effect of relative humidity was tested using the method described by Beyer et al. (2004) with slight changes. RHs tested were 29.8% CaCl2, 52.6% Ca(NO3)2, 75.3% NaCl,, 84.7% KCl,, 92.7% KNO3 and 100% deionized water. The results show that no strain germinated at 4 and 10°C. At 22°C all isolates exceeded 95% germination after 24 h. Temperatures over 25°C had a negative influence on the rate of spore germination. Incubation of conidia at low humidity (RH 29%) suppressed germination for all strains. All relative humidities over 29.8% were found favorable for germination of all this strains.
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Beauveria brongniartii
