Characterization of the occurrence pattern of plant diseases in Roraima, Brazil. = Caracterização do perfil da ocorrência de doenças de plantas no estado de Roraima.
2011
Bernardo de Almeida Halfeld-Vieira | Kátia de Lima Nechet | Giovanni Ribeiro de Souza
A systematic survey of plant pathogens was performed during 91 months with the objective to determinate the phytopathological profile and provide support for actions in plant protection in Roraima, Brazil. Surveys of symptomatic plants were performed in 13 of 14 state municipalities. Pathogens were identified using taxonomic keys (fungi), biochemical tests (bacteria), pernineal patterns (nematodes from genus Meloidogyne), serology or PCR allied to transmission electron microscopy (viruses). Data analysis was done calculating the relative frequencies, adjusting the frequency of monthly occurrences to Weibull model and calculating the linear Pearson (r) correlation coefficient to analyze the relationship between precipitation and relative frequency of monthly occurrences. Rhizoctonia solani was the most frequently recorded species followed by cercosporoid fungi. Greatest number of species and frequency of disease occurrence were observed in Boa Vista, Mucajaí, Cantá and Alto Alegre municipalities, which are more expressive population and agricultural activity. One to two months after increased precipitation periods there is a strong tendency to an increase of disease incidence frequency.
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