Dispersão temporal de conídios de Botryosphaeriaceae em parreirais no Vale do Siriji (Pernambuco) e sensibilidade de isolados do Nordeste brasileiro a fungicidas

Abstract

The Botryosphaeriaceae dieback is an important disease that occurs in vineyards around the world. Pathogens infect the trunk of the vine by moving toward the central regions such as xylem and wood, promoting slow plant death. In Brazil, studies related to the Botryosphaeriaceae dieback in grapevine are scarce, the first reports of Botryosphaeriaceae dieback occurring in grapevine, dates back to 1992. Recent studies based on phylogenetic analyzes have demonstrated a wide variation of species associated with symptoms characteristic of this disease in different regions in the Northeast Region. For the proper management of phytopathogens, it is important to know a series of factors including the pathogen dispersal in the area of crop and the availability of methods for the management of the disease. In this sense, this thesis had as objectives: (a) To analyze the conidia dispersal of Botryosphaeriaceae species in vineyards in the Northeast region of Brazil; (b) To evaluate the sensitivity of isolates of Lasiodiplodia theobromae obtained in different grape producing areas in the Northeast of Brazil to different groups of fungicides. The dispersal study was conducted in four table grape producing areas, located in tropical region (Sirijí Valley) in the state of Pernambuco (Brazil). The conidia dispersal in symptomatic plants and pruning debris throughout the year was evaluated. The conidia dispersal data had a Goodness-of-fit to the logistic mathematical model, indicating that it could be used for future disease prediction studies. In the sensitivity study of L. theobromae the in vitro susceptibility and adaptability components of 62 symptomatic grapevine isolates originating in the Northeast of Brazil were evaluated for tebuconazole, thiophanate-methyl, azoxystrobin and iprodione. In vitro susceptibility to azoxystrobin revealed that the populations of L. theobromae in the Northeast of Brazil show different degrees of sensitivity to the fungicides tested with different values for sensitivity to tebuconazole, thiophanatomethyl, iprodione and azoxystrobin, with EC50 ranging from 0.044 to 3 μg.ml-1 for most isolates. The understanding of the dispersal of Botryosphaeriaceae conidia in the vineyards as well as the current state of the sensitivity of L. theobromae populations to different fungicides can provide parameters to establish the best management strategies for Botryosphaeriaceae dieback.