Biological characterization of some microorganisms of biotechnological interest.

Successful use of biological insecticides depends on their quality, which ensures the biological efficacy and performance of bioproducts in field conditions: the active substance have to be virulent and to have ecological competences (epizootiological qualities, multiplication capacity, spreading and persistence in habitats and target pests populations).These parameters are objective criteria for selection of microorganisms that can be successfully included in biological control programs of pests. In this paper are presented results of some laboratory tests aimed to estimate biological parameters specific for entomopathogenic fungi, including the spores germination and spores production on culture media and insects. The biological material used in this study consisted in five Beauveria bassiana entomopathogenic biotypes, isolated from insects belonging to the ord. Coleoptera, Hymenoptera and Diptera in natural epizootic outbreaks, during the years 2008-2010. The results led to the following conclusions: (i) B. bassiana strains having different origins in terms of habitat and host insect exhibit different biological qualities, (ii) the evaluation of test insects mortality induced by B. bassiana doesn’t provides a complete pathological characterization of fungal isolates; to assess the biological control potential of B. bassiana isolates, the virulence have to be correlated with the biological cycle of the fungus and the spores production on the insect cuticle; (iii) the quantification of spore production on insect is also necessary to further evaluate the fungal strains potential to naturally increase of virulence.