Taxonomia e epidemiologia comparativa de Botryosphaeriaceae associada à gomose do cajueiro

Abstract

The gummosis out as a major disease reported in all producing regions of cashew in Brazil. In this study we identify, characterize and evaluate the comparative epidemiology of species Botryosphaeriaceae associated with gummosis in Anacardium in Brazil. A total of 138 isolates were sampled and identified using a combination of morphological analysis and phylogenetic based on the partial sequence of the translation elongation factor 1-α sequence (EF-1α), internal transcribed spacers (ITS) and sequence of the β-tubulin. ten species were identified Botryosphaeriaceae: Lasiodiplodia brasiliense, L. euphorbicola, L. gonubiensis, L. iraniensis, L. jatrophicola, L. gravistriata sp. nov., L. pseudotheobromae, L. theobromae, Neofusicoccum batangarum and Pseudofusicoccum stromaticum. Only L. theobromae previously described in cashew tree, while all other species are reported for the first time in association with cashew trees in Brazil and worldwide. Lasiodiplodia theobromae was the prevalent species. All species of pathogenic Botryosphaeriaceae were highlighted in branches of cashew. There were significant differences between species with N. batangarum, L. iraniensis, L. jatrophicola and L. gravistriata being the most aggressive species, while L. euphorbicola, L. pseudotheobromae were less aggressive. All species of Botryosphaeriaceae caused symptoms in alternative hosts tested except P. stromaticum, L. brasiliense and L. iraniensis had the highest injury in avocado, banana, guava, papaya, mango and passion fruit. L. jatrophicola showed lower aggressive in the hosts, as N. batangarum was not pathogenic in passion fruit and only L. gravistriata caused symptoms in melon. Our results suggest that these alternate hosts serve as a potential source of inoculum. Species Botryosphaeriaceae demonstrated reduction in mycelial growth in the presence of Thiophanate-methyl fungicides, difenoconazole and azoxystrobin. The response sensitivity present variation according to the species of the fungicides and Botryosphaeriaceae.