Etiologia e controle da antracnose em frutos de banana no Brasil

Abstract

Colletotrichum spp. is a pathogenic fungus of great importance in banana cultivation since it is the causal agent of anthracnose and affects the fruit both in the field and in the post-harvest period, depreciating its commercial value. This disease is widely distributed in the regions where the banana is cultivated. However, there are different levels of virulence, suggesting the existence of genetic variability among Colletotrichum spp. Thus, the present study aimed to identify Colletotrichum species associated with anthracnose of banana fruits, to verify the genetic diversity of Colletotrichum spp. and to determine the in vitro mycelial sensitivity of the isolates, submitted to concentrations of 2 chemical fungicides and a microbiological one. A total of 65 isolates of Colletotrichum spp. were obtained from banana fruits of the varieties Prata and Nanica, from different Brazilian states. The isolates were submitted to morphological, pathogenic and molecular characterization, in addition, an in vitro sensitivity test was performed on fungicides. Morphological and cultural characters were not informative for distinguishing Colletotrichum species. All isolates tested were pathogenic. In the molecular characterization were used 12 primers ISSR and phylogenetic analysis using the gene GAPDH, which allowed to differentiating the isolates in five species, of which three had not yet been associated to the banana anthracnose. In the in vitro susceptibility test, among the fungicides, the microbiological was the one that showed the highest efficiency in the control of the tested isolates, in addition, no resistance to any of the tested fungicides was observed. The results obtained with this study contribute to the knowledge about the etiology of anthracnose in banana, being of extreme import ance for the development of control strategies contributing to minimize the damage caused by the pathogen.