RESUMO
AIMS: To monitor and select genetically characterized strains of Beauveria brongniartii to be used as microbiological control agents against Melolontha melolontha in different climatic conditions of the Valley of Aosta (northwest Italy). METHODS AND RESULTS: Molecular random amplified polymorphic DNA markers allowed monitoring of five B. brongniartii strains (C2, F, K2, N3 and W2) in field trials. Ten sites were chosen at Jovençan, Saint-Pierre and Quart areas, where a mixture of the five strains colonizing rye kernels was applied to the soil of each M. melolontha infested site. Growth, persistence and virulence on M. melolontha larvae of five fungal strains were evaluated in two subsequent 24-month studies. Beauveria brongniartii grew best at the Jovençan sites. Not only did strain F persist better than the other strains in most soil samples but it was also the most virulent strain. Strain F was isolated the most frequently from infected M. melolontha larvae recovered from the test sites. A general decrease in the larvae rate was detected in the test field soil. CONCLUSIONS: Strain F of B. brongniartii was better than other strains in growth, persistence and virulence against M. melolontha larvae in the test site soil. SIGNIFICANCE AND IMPACT OF THE STUDY: Results obtained from preliminary field trials support the use of strain F as a biological control agent against M. melolontha in the Valley of Aosta even if further targeted studies are still necessary.
Assuntos
Besouros/microbiologia , Hypocreales/patogenicidade , Controle Biológico de Vetores/métodos , Microbiologia do Solo , Animais , DNA Fúngico/análise , Ecossistema , Marcadores Genéticos/genética , Hypocreales/classificação , Hypocreales/genética , Hypocreales/crescimento & desenvolvimento , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Secale/microbiologia , VirulênciaRESUMO
Propolis, a multifunctional substance used by bees to maintain the safety of their hives, is popular for its therapeutic potential against some micro-organisms. Ethanolic extracts of two propolis specimens, collected from different areas within a region in the north-west of Italy, were examined to evaluate their antimicrobial activity against 46 Streptococcus pyogenes strains. By both agar dilution and agar diffusion methods, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were = 234 microg ml-1, corresponding to a one in 512 dilution of the 12% (w/v) extracts. One of the two propolis samples was more active and this extract was shown to be richer in the flavonoids pinocembrin and galangin using HPLC. Therefore, with a simple microbiological assay technique, in particular the agar dilution method, it was possible to standardize the analysis of propolis samples to identify the quality parameters of this natural product before use for medical treatment.
Assuntos
Própole/farmacologia , Streptococcus pyogenes/efeitos dos fármacos , Criança , Humanos , Testes de Sensibilidade Microbiana/métodos , Faringite/microbiologia , Própole/isolamento & purificação , Infecções Estreptocócicas/microbiologia , Tonsilite/microbiologiaRESUMO
Within a three years research program, infection tests were carried on adults of Corythucha ciliata wintering on the plane-trees of same city avenues, inoculating entomopathogenic deuteromycetes Beauveria bassiana, Verticillium lecanii, Paecilomyces farinsus, microorganisms which are known to be naturally present in such an environment. Inoculated fungi were able to settle only where the trees were free from any kind of disturbance, while this failed to occur in the areas of intense car traffic. Number of treatments efficiently affected pathogens diffusion in the trees. The persistency of the parasites on the insects, even one year after the treatment, seems to indicate the possibility of their use for the limitation of C. ciliata.