Utilização de fungos endófitos do cacaueiro como biocontroladores de Crinipellis perniciosa

• Ano de defesa: 2008
• Autor(a) principal: Agredo Hoyos, Julian Mauricio
• Orientador(a): Pfenning, Ludwig Heinrich
• Banca de defesa: Resende, Mário Lúcio Vilela de, Marco Antônio Galleas, Aguilar
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Lavras; Escola de Ciências Agrárias de Lavras (ESAL)
• Programa de Pós-Graduação: Programa de Pós-Graduação em Agronomia/Fitopatologia
• Departamento: Departamento de Fitopatologia
• País: BRASIL
• Palavras-chave em Português: Fungos endófitos; Theobroma cacao; Biocontrole; Crinipellis perniciosa; Vassoura-de-bruxa; Plântulas; Endophytic fungi; Biocontrol agents; Witches´ broom; Seedlings
• Área do conhecimento CNPq: Ciências Agrárias
• Link de acesso: https://repositorio.ufla.br/handle/1/2785

Witches´ broom, the most damaging disease of cacao caused by the fungus C. perniciosa, considerably reduces the production of cacao and has been subject of study in recent years, such as research on biological control, mainly through use of endophytic fungi. The objectives of this work were: i) assess endophytic fungi of cacao from two states in Brazil: Bahia and Pará, in its ability to control the disease and ii) ascertain the presence or absence of fungal endophytes in the early stages of growth of cacao seedlings. The experiments were made in laboratories and in a greenhouse of Federal University of Lavras. The fungi were inoculated in the concentration of 6x106 propagules mL-1. The experiment with Bahia endophytes had nine treatments: Colletotrichum gloeosporioides, Clonostachys rosea, Cladosporium sp., Trichoderma sp., Colletotrichum acutatum, Fusarium semitectum, cocktail (the six fungi mix), and inoculated and without inoculated witness. The experiment with Pará endophytes had seven treatments: Pestalotiopsis sp., Clonostachys rosea, Fusarium subglutinans, Trichoderma sp., Acibenzolar-S-methyl ASM (dose 0.2 g/L-1 a.i..), and inoculated and without inoculated witness. Assessments of the disease were made at 30, 45 and 60 days after inoculation of C. perniciosa. It was the presence of fungi in the seedlings before and after inoculation of the endophytes fungi. The antagonistic action of Trichoderma sp. and C. rosea against C. perniciosa was assessed in an in vitro assay. Isolation of cacao seedlings to know their diversity and frequency of associated fungi were also made. The endophyte C. rosea (from Pará) and ASM treatment partially controlled the disease. Fungi were encountered in seedling before the inoculation of endophytes; after inoculation, F. semitectum was the only endophyte not reisolated. In the in vitro assay, the fungi tested inhibited the growth of C. perniciosa. In seedlings of cacao, the more frequently genera isolated were Trichoderma, Colletotrichum, an Ascomycete of Bionectriaceae family and Fusarium. It was concluded that C. rosea and ASM have the potential to control the witches´ broom and that some endophytic fungi can be associated with the first stages of growth of common cacao seedlings.