Potencial de Pseudomonas aeruginosa na redução da severidade de doenças foliares do arroz no município de Pirapemas – MA

Abstract

Rice (Oryza sativa) is a product of great socioeconomic importance for many countries, especially developing countries, and is a staple food for about 2.4 billion people. Rice crop yield can be impaired by a number of factors, such as fungal diseases, which cause 20-50% damage to rice yield. The main measures for rice disease management are the use of resistant cultivars and fungicides. However, hardy rice cultivars are often unavailable for sale or shortened due to lack of use strategy, whereas the use of fungicides in addition to raising production costs has low efficiency and may pose a risk to the environment. Therefore, the objective of this work was to evaluate the effects of the use of bacterial strains Pseudomonas aeruginosa in the management of the main diseases of rice crop, through seed microbiolization and application of bacterial solution in the leaf area of plants. P. aeruginosa bacterial strains SNF and DACAR were used. For the preparation of the treatments, these strains are part of the biological collection of the Laboratory of Phytopathology of the State University of Maranhão. The treatments were: absolute control; fertilizer witness; microbiolized seeds with SNF + spray at 30 and 60 days; microbiolized seeds with DACAR + spray at 30 and 60 days; microbiolized seeds with SNF + fertilizer + spray at 30 and 60 days; microbiolized seeds with DACAR + fertilizer + spray at 30 and 60 days; microbiolized seeds with SNF and DACAR + spraying at 30 and 60 days; microbiolized seeds with SNF and DACAR + fertilizer + spray at 30 and 60 days. The severity of brown spot, scalding, narrow spot, grain spot and leaf spot disease were evaluated using disease-specific grade scales. The results showed that bacterial isolates of P. aeruginosas SNF and DACAR showed potential for biocontrol of leaf blight and brown spot rice diseases. The use of strains SNF and DACAR may be an important alternative for rice disease control, as these bacteria have several mechanisms of action against pathogens, which prolongs the efficiency of this method