Controle alternativo da murcha bacteriana do pimentão utilizando óleos essenciais vegetais e silicato de cálcio

• Ano de defesa: 2012
• Autor(a) principal: ALVES, Aldenir de Oliveira
• Orientador(a): MARIANO, Rosa de Lima Ramos
• Banca de defesa: SILVA, Márcia Vanusa da, ANDRADE, Domingos Eduardo Guimarães Tavares de, LARANJEIRA, Delson, SILVA, Adriano Márcio Freire
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• dARK ID: ark:/57462/0013000007mxr
• Idioma: por
• Instituição de defesa: Universidade Federal Rural de Pernambuco
• Programa de Pós-Graduação: Programa de Pós-Graduação em Fitopatologia
• Departamento: Departamento de Agronomia
• País: Brasil
• Palavras-chave em Português: Ralstonia solanacearum; Capsicum annuum L.; Biofumigação; Cymbopogon martini
• Área do conhecimento CNPq: FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6478

The bacterial wilt caused by Ralstonia solanacearum (Rs) race 1, is an important bacterial disease in Pernambuco and other states of Brazil. This study aimed to evaluate the effectiveness of essential oils and silicon (Si) on alternative disease control, their effects on Rs, and verify the putative mechanisms involved in these processes. The oils of bergamot, copal, fennel, peppermint, sweet orange, lemon, cinnamon, lemon grass, eucalyptus citriodora, eucalyptus globulus, clary sage, and palmarosa were evaluated by biofumigation. Soil was previously infested with Rs (filotype I, race 1, biovar 3, biotype 8) at 5x108 CFU ml-1 and after seven days biofumigated during four days with the twelve oils (0.14%, v:v) under greenhouse conditions, and with bergamot, sweet orange and palmarosa in field. It was evaluated: the latency period (PL50), incidence, index of bacterial wilt (IBW) and area under the disease progress curve (AUDPC), plant development, Rs population in soil, soil characteristics, and Rs growth in vitro. The oils of palmarosa, bergamot and sweet orange elevated the PL50 and reduced IBW and AUDPC up to 15, 60 and 64.4%, respectively in greenhouse. In the field only palmarosa elevated the PL50 (38%), reduced the IMB (36%) and AUDPC (38%), and increased the number of fruits per plant. Only under greenhouse conditions soil biofumigated with oils of bergamot and sweet orange had higher sodium levels than those treated with palmarosa or control, which did not differ among them. In vitro, the growth of Rs was inhibited by the oil of palmarosa. To evaluate the effect of silicon (Si), sweet pepper plants cv. Enterprise were grown in compost containing 0.00, 0.25, 0.50, 1.50 and 3.00 g of SiO2 kg-1 of compost and transplanted into soil infested with isolate Rs CGM-8, being evaluated PL50, incidence, IMB and AUDPC; fresh and dry weight of shoot and root biomass, accumulation of Ca+2, Mg+2 and Si, total protein and enzymatic activity; chemical characteristics of substrate, and in vitro growth. The dose 3.00 g of SiO2 increased PL50 (34%), reduced IMB (63%) and AUDPC (47.4%), increasing also Ca+2 in shoots and reducing Mg+2 in shoots and roots. Supplementation with different Si doses resulted in maximum increments of fresh weight of shoot (121.8%), fresh weight of root (83.6%), and dry weight of shoot (84.9%); increased total protein, catalase, ascorbate peroxidase, and quitinase. Si was accumulated in the shoots and compost; pH, Na+ and K+ were elevated and P was reduced in the compost. The putative mechanisms of action of Si on disease control were direct action on the pathogen colonization, indirect action on plant growth, increase of Ca+2 absorption and signaling for producing plant defense enzymes. In conclusion, biofumigation with palmarosa oil and transplant production in compost containing calcium silicate are potential alternative strategies for the control of bacterial wilt of sweet pepper.