Utilização do extrato aquoso de cinamomo no controle da antracnose da videira Use of aqueous extract of chinaberry to control grapevine anthracnose

Abstract

O objetivo desse trabalho foi avaliar o efeito do extrato aquoso de cinamomo (Melia azedarach L.) sobre Elsinoe ampelina, agente etiológico da antracnose da videira, e no controle da doença. Para os experimentos de crescimento micelial, esporulação e geminação de conídios do fungo foram utilizadas as concentrações de 0, 10, 20, 30, 40 e 50 mL L-1 de extrato, além dos tratamentos padrões com calda bordalesa e mancozebe. Em condições de campo, um experimento foi conduzido em vinhedo comercial por dois ciclos consecutivos (2009/2010, 2010/2011), no qual se avaliaram concentrações crescentes de extrato, acrescidos de óleo vegetal (2,5 mL L-1), além de uma testemunha absoluta (sem tratamento) e do tratamento padrão com calda bordalesa. A partir de 20 mL L-1 de extrato, houve total inibição da esporulação. Enquanto que a concentração de 50 mL L-1 diminuiu em 99,4% o diâmetro da colônia do fitopatógeno, não diferindo do tratamento com calda bordalesa, além de reduzir a germinação de conídios em 84,8 e 90,8% em relação à testemunha, 12 e 24 horas após incubação. No primeiro ano do experimento de campo, houve efeito linear negativo das concentrações do extrato sobre a severidade da antracnose. No entanto, no segundo ano, o uso de óleo vegetal como adjuvante mascarou o efeito do extrato. A aplicação isolada de óleo vegetal reduziu em 64,0% a AACPD, similar aos resultados obtidos com todas as concentrações de extrato de cinamomo e com o tratamento padrão com calda bordalesa.<br>The aim of this study was to evaluate the effect of aqueous extract of chinaberry (Melia azedarach L.) on Elsinoe ampelina, the etiological agent of grapevine anthracnose, and on the disease control. For the trials of mycelial growth, sporulation and conidium germination, the concentrations 0, 10, 20, 30, 40 and 50 mL L-1 extract were used, besides standard treatments with bordeaux mixture and mancozeb. Under field conditions, an experiment was conducted in a commercial vineyard for two consecutive cycles (2009/2010, 2010/2011) to evaluate increasing concentrations of extract and vegetable oil (2.5 mL L-1), in addition to an absolute control (without treatment) and standard treatment with bordeaux mixture. Concentrations equal to or higher than 20 mL L-1 extract led to complete inhibition of sporulation. The concentration of 50 mL L-1 decreased by 99.4% the colony diameter and did not differ from the treatment with bordeaux mixture, besides reducing conidium germination by 84.8 and 90.8%, compared to control, at 12 and 24 hours after incubation. In the first year of the experiment in the field, there was a negative linear effect of extract concentrations on anthracnose severity. However, in the second year, the use of vegetable oil as adjuvant masked the extract effect. The isolate application of vegetable oil reduced AUDPC by 64.0%, which is similar to the results obtained with all concentrations of chinaberry extract and the standard treatment with bordeaux mixture

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oai:doaj.org/article:4d5a19a3dccb4c1d882f0f1d00ec31faLast time updated on 12/18/2014

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