Doenças causadas por fungos Botryosphaeriaceae em videira: caracterização fenotípica e molecular de isolados e sensibilidade a fungicidas

Abstract

Different species in Botryosphaeriaceae fungi are commonly associated with black dead arm, bot canker, dieback, excoriose and esca diseases of grapevine. These grapevine trunk diseases are of major importance in Portugal and in many other grapevine growing regions of the world. The phenotypic and molecular characterisation of 43 Botryosphaeriaceae isolates, obtained from grapevine propagating materials, young and mature vine plants, allowed the identification of B. dothidea (two isolates), “B”. obtusa (19 isolates), “B”. stevensii (three isolates), “B”. viticola (one isolate), “B”. lutea (one isolate), “B”. parva (14 isolates) and “Botryosphaeria” spp. (three isolates). This is the first record of “B”. viticola in Portugal. Pathogenicity tests carried out with Botryosphaeriaceae isolates in grapevine (in vivo assays) revealed the intra-specific variation among isolates. The efficacy of tebuconazol, pyraclostrobine, pyraclostrobine+metiram and cyprodinil+fludioxonil fungicides as mycelial growth inhibitors was confirmed against B”. parva, “B”. obtusa, “B”. lutea e “B”. stevensii, being cyprodinil+fludioxonil the best fungicide tested (lowest EC50 values). The efficacy of pyraclostrobine, metiram, and pyraclostrobine+metiram as spore germination inhibitors was confirmed against “B”. parva and “B”. obtusa, being pyraclostrobine+metiram the best fungicide tested (lowest EC50 values). The potential use of such fungicides to control the Botryosphaeriaceae diseases in the field is promising, as often in the same vine different Botryosphaeriaceae species are present. This would also allow the alternation of products to avoid resistance risks.