Processo infeccioso de Botrytis cinerea em folhas de eucalipto

• Ano de defesa: 2013
• Autor(a) principal: Caires, Nilmara Pereira
• Orientador(a): Furtado, Gleiber Quintão
• Banca de defesa: Kasuya, Maria Catarina Megumi , Rodrigues, Fabrício de ávila , Pereira, Olinto Liparini
• 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: Eucalipto - Doenças e pragas; Mofo-cinzento; Microscopia
• Palavras-chave em Inglês: Eucalyptus - Diseases and pests; Gray mold; Microscopy
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4432

Gray mold (MC), caused by the fungus Botrytis cinerea, is one of the most important diseases that occurs in Eucalyptus nurseries worldwide. Therefore, a better understanding of the interaction between B. cinerea and Eucalyptus sp., including the conditions that favor pathogen growth, is key to the development of effective strategies for disease management. All experiments were carried on detached leaves on detached leaves of eucalyptus urograndis clone CNB011, inoculated with a suspension of 105 conidia of B. cinerea/mL. Prior to the evaluations to assess the effect of leaf side, age and luminosity the development of infective structures of the fungus, inoculated leaves were bleached with etanol and chloral hydrate and analyzed under an optical microscope. Disease severity was assessed 10 days after inoculation. SEM analyses were performed on leaf tissue collected 2, 4, 6, 12, 24 and 48 hours after inoculation (hai). There were significant effects of leaf side and luminosity on conidia germination. The highest germination percentage (92%) and severity (21%) were observed on the adaxial surface of leaves when incubated in the dark. Although the percentage of conidia germation on the surface of young and old leaves did not differ statistically, disease severity on young leaves was 34-fold higher when compared to old leaves (17.3% and 0,5% repectively). SEM analyses showed conidia germinated producing 1-4 germ tubes, but did not form appressorium. The germ tubes penetrated directly only the surface of intact leaves (but not stomata). Inter and intracellular colonization of the mesophyll by pathogen s hyphae could be observed at 120 hai. The fungus reproduces by producing macronematous conidiophores (on the leaf surface of both sides) and micronematous conidiophores (in the subepidermal region). Although the infectious process B. cinerea in different hosts are well described, this is the first study of this pathogen in eucalyptus leaves.