Factors affecting the spatio-temporal dynamics of Fusarium wilt of bananas in Brazil

• Ano de defesa: 2019
• Autor(a) principal: Heck, Daniel Winter
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Fitopatologia
• Palavras-chave em Português: Banana - Doenças e pragas; Epidemiologia; Fusarium; Fitopatologia
• Link de acesso: https://locus.ufv.br//handle/123456789/30093

Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. cubense (Foc), is one of the most destructive diseases of bananas. Great yield losses have been recorded for decades. Nevertheless, information about FW epidemiology is scarce. There is no basic information about the disease intensity, spatio-temporal pattern, spread mode and potential factors involved in these processes. This study aims to answer some of the epidemiology gaps to support the design of efficient management strategies. Initially, a survey was carried out in 30 banana fields in the main producing regions of Brazil. In total, 95 ha and more than 100 thousand plants were evaluated. Aggregation of FW was detected by all analytical methods in 43% of the fields. FW was more aggregated in high-input fields. The incidence of FW in banana fields in Brazil is high and is affected predominantly by cultivar, soil physical factors, and field management. The spatio-temporal patterns of FW epidemics were studied in eight plots, totaling 5 ha. All plants were evaluated bimonthly to FW symptoms and spatio-temporal analyses were conducted. The monomolecular model best fit incidence data over time. Aggregated patterns of diseased plants were frequently observed by quadrat-based methods, and the level of aggregation was higher when FW incidence was also high. The clusters of diseased plants were randomly distributed in most plots. The possible aerial dispersal of Foc under field conditions was investigated and spores of the pathogen were caught in Burkard spore trap. To investigate whether weevil borer (Cosmopolites sordidus; WB) was an effective vector of FW a comparative epidemiology study under field conditions and an association study between Foc and WB were performed. Incidence of FW was lower in the field where the population of WB was managed with Beauveria bassiana and higher degree of disease aggregation was observed. A great number of Fusarium spp. isolates were associated with WB but none was Foc. The design of efficient management strategies to mitigate the damage of Foc race 1 and the risk of introduction of Foc tropical race 4 require solid knowledge of FW epidemiology.