Sensibilidade de isolados de Hemileia vastatrix a azoxistrobina e tebuconazol

• Ano de defesa: 2010
• Autor(a) principal: Bragança, Carlos Augusto Dórea
• Orientador(a): Mizubuti, Eduardo Seiti Gomide
• Banca de defesa: Brommonschenkel, Sérgio Hermínio , Nascimento, Robson José do
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitopatologia
• Departamento: Etiologia; Epidemiologia; Controle
• País: BR
• Palavras-chave em Português: Fungicidas; Hemileia vastatrix; Ferrugem-do-cafeeiro
• Palavras-chave em Inglês: Fungicides; Hemileia vastatrix; Coffee leaf rust
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4381

Monitoring the sensitivity of pathogens to fungicides is a crucial step to understand the processes associated with the emergence of resistance, distribution of resistant isolates, the evolution of insensitive populations, and the impacts on disease control. The management of coffee leaf rust (Hemileia vastatrix), the most destructive coffee disease, is based on chemical control, however there was no information about sensitivity of H. vastatrix to fungicides. Isolates of H. vastatrix were collected in the main producing regions of Minas Gerais and Espírito Santo states, and the sensitivity to azoxistrobin and tebuconazole was determined by estimating either the effective dose to inhibit 50% germination or fungal growth (ED50). The ED50 values for azoxistrobin varied between 0.004 and 0.12 μg/ml and for tebuconazole between 0.01 to 5.11 μg/ml. There was no association of ED50 values with isolate origin or fungicide regimes for both azoxistrobin (χ2 = 0.63; P=0.42 e χ2 = 0.15; P=0.70) and tebuconazole (χ2 = 3.23; P=0.20 e χ2 = 0.24; P=0.89). There was no association between geographic distance and ED50 values, therefore there was no spatial clustering of sensitivity of isolates to both fungicides. Both fungicides reduced germination and germ tube elongation. The primers used did not allow amplification and sequencing of the genomic regions associated with tebuconazole action site in the pathogen. For azoxistrobin, partial sequence was obtained for the CYTB gene, but, consistent with the results from the phenotypic test, no mutations known to confer fungicide insensitivity were detected. There is no evidence of resistance in H. vastatrix to both azoxistrobin and tebuconazole.