Escala diagramática e controle alternativo da mancha de ramularia do algodoeiro

• Ano de defesa: 2006
• Autor(a) principal: Aquino, Leonardo Angelo de
• Orientador(a): Berger, Paulo Geraldo
• Banca de defesa: Cecon, Paulo Roberto , Chiavegato, Ederaldo José
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Manejo integrado de doenças; Ramularia gossypii; Severidade; Calda Viçosa; Silicato de potássio
• Palavras-chave em Inglês: Integrated pest management; Ramularia gossypii; Severity; Calda Viçosa; Potassium silicate
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4553

This study aimed to elaborate and validate a diagrammatic scale to assess the severity of areolate mildew (Ramularia gossypii (Speg.) Cif.) on cotton leaves as well as to test the efficiency of alternative products to control this disease. The proposed scale showed disease levels of 0, 0.05, 0.50, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0 and 67.20%. Both precision and accuracy were evaluated by using regression between the real and estimated severity by raters with and without experience. The reproductibility of the scale by regression analysis of the estimated severities by raters was also evaluated. The scale showed to be adequate to evaluate areolate mildew due to an increase in accuracy and precision during disease evaluation, which gives reproductible estimatives of disease severity. Regarding the alternative products used to control areolate mildew, the potassium silicate was not efficient to control this disease with values of severity, canopy quality at 166 days after plant emergence, yield and area under areolate mildew progress curve (AAAMPC) similar to the check treatment (no fungicide applied). The treatment with Calda Viçosa gave the best disease control and did not differ from the treatments with Pyraclostrobin or Tebuconazole in terms of yield, but showed an increase of 88% in yield compared to the check treatment. The fungicides Mancozeb and Clorothalonyl mixed with Calda Viçosa or with Tebuconazole were efficient to control the disease, especially the mixture of fungicide Mancozeb with Tebuconazole.