Identificação e caracterização de espécies de Botryosphaeriaceae na cultura da mangueira no nordeste do Brasil

Abstract

Dieback and stem-end rot are diseases caused by species of Botryosphaeriaceae have been associated with serious yield losses to mango culture in northeastern Brazil and worldwide. Considering the increasing importance of these diseases and recent discovery of several species of Botryosphaeriaceae, the objective of this study was (i) to identify species of Botryosphaeriaceae associated with dieback and stem-end rot of mango in the semi-arid region of northeastern Brazil and (ii) compare the species in relation to mycelial growth, pathogenicity and virulence. A total of 235 isolates of Botryosphaeriaceae were identified using morphological and DNA sequence data (ITS and EF1-α). The following species were found: Botryosphaeria dothidea, B. mamane, Lasiodiplodia crassispora, L. egyptiacae, L. hormozganensis, L. iraniensis, L. pseudotheobromae, Lasiodiplodia sp., L. theobromae, Fusicoccum fabicercianum, Neofusicoccum parvum, Neofusicoccum sp., Neoscytalidium dimidiatum e Pseudofusicoccum stromaticum. Only B. dothidea, L. theobromae, N. parvum and P. stromaticum had been previously reported, while the other species represent the first report associated with the mango diseases in this country. L. theobromae, B. dothidea and P. stromaticum were the most frequently isolated species. There were significant differences in mycelial growth rates among the Botryosphaeriaceae species and also in the optimum temperature for growth. The optimum temperature and mycelial growth rates for species Lasiodiplodia vary from 28.2 to 31.1 ºC and from 36.4 a 49.1 mm/day, respectively. While in the other species, the variation was from 25.4 to 30.8 ºC and 19.7 to 41.2 mm/day. All species were pathogenic in mango fruit. There were significant differences in virulence among the species. L. hormozganensis and Lasiodiplodia sp. were the most virulent. For the other species within the Botryosphaeriaceae family, N. dimidiatum and N. parvum were the most virulent species, B. mamane, L. crassispora e L. viticola are reported for the first time associated with mango diseases worldwide.