Damages caused by Bipolaris maydis in Panicum maximum cv. Tanzania

The aim of this research was to evaluate the damage caused by Bipolaris maydis in the quantity and quality of the Tanzania grass production. Tanzania grass plants were cultivated in pots of PVC tubes (50 cm of height x 15 cm of diameter) containing a mixture of soil and sand (3: 1). The plants were inoculated with spore pathogen suspension containing 10(2), 10(4) and 10(6) conidia/mL to obtain different levels of disease. Severity and number of tillers were evaluated weekly. After four weeks, it were evaluated the weight of the fresh matter of leaves (FM), percentage of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). The disease reduced significantly the plant tillering and FM after the second evaluation (P < 0.05). There was no significant correlation among the variables DM, ADF, and the area under disease progress curve (AUDPC). However, there were positive (P < 0.01) and negative (P < 0.05) correlations among CP and NDF, respectively, with AUDPC, as possible result of the activity of the pathogen. These results showed that B. maydis inhibits the development of the Tanzania grass and promotes alteration in the quality of the forage.