Período de incubação de Guignardia citricarpa em frutos de laranja ‘Valência’ e importância das pulverizações de cobre no controle da mancha preta
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Data
2011-02-28
Autores
Aguiar, Ronilda Lana [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A mancha preta dos citros (MPC), causada pelo fungo Guignardia citricarpa, produz lesões nos frutos que os depreciam para o mercado interno e os restringem para a exportação. O grande período de suscetibilidade dos frutos, em adição ao fato do patógeno causar infecções latentes, dificulta o entendimento do período de incubação da doença. O objetivo do trabalho foi determinar se o período de incubação da mancha preta do citros. Inoculou-se frutos de laranjeira ‘Valência’ em diferentes estádios fenológicos e também foi determinado a importância das pulverizações de fungicida cúprico, da fase de queda das pétalas e, até sete meses após, no controle da mancha preta dos citros. Os resultados obtidos indicaram uma relação linear negativa entre o período de incubação da MPC e o diâmetro dos frutos inoculados. O período de incubação em frutos inoculados, ainda imaturos (2,0, 2,5 e 3,0 cm de diâmetro), foi longo, sendo de 266 dias nos de menor diâmetro menor, enquanto que em frutos já desenvolvidos (5,0 e 7,0 cm de diâmetro) o período para expressão de sintomas foi mais curto, sendo de cerca de 30 dias. A mancha preta em frutos cítricos apresenta período de incubação variável, dependente do estádio fenológico em que os frutos tornaram-se infectados. A concentração do inóculo de Guignardia citricarpa não interfere no período de incubação da doença. Em relação à incidência da MPC, mesmo com seis pulverizações de cobre a cada 28 dias, 53,3% dos frutos expressaram sintomas da doença. Quanto à severidade, não há diferença de resposta entre os tratamentos. Portanto, os dados mostraram que as infecções precoces interferem na qualidade visual do fruto, porém não na produção. Com o crescimento dos frutos, as infecções interferem negativamente na produção, levando a um aumento na queda de frutos
The citrus (Citrus spp.) black spot, caused by Guignardia citricarpa produces lesions on the fruit that depreciate the domestic market and to restrain them for export. The great period of susceptibility of the fruits in addition to the fact that the pathogen causing latent infection of complicates the understanding of the incubation period of the disease. The aim of this study was to determine the incubation period of the citrus black spot is constant or variable, inoculating fruits of 'Valência' orange at the different phenological stages and was also given the importance of copper fungicide sprays, stage of petal drop and up to seven months in the control of citrus black spot The results indicate a negative linear relationship between the incubation period of the CBS and the diameter of the fruits inoculated. The incubation period observed in fruits inoculated still immature (2,0, 2,5 and 3,0 cm diameter) was long, smaller in diameter occurred around 266 days, and fruits already developed (5,0 and 7,0 cm diameter) for the disease expression was shorter in diameter occurred in approximately 30 days. The citrus black spot has a variable incubation period depends on the phenological stages in which fruit is inoculated. The concentration of inoculum of Guignardia citricarpa not interfere with the incubation period of the disease. Regarding the incidence of CBS, even with six copper sprays every 28 days, 53.3% of the fruit expressed disease symptoms. For severity, there is no difference in response between treatments. Therefore, the data showed that early infections influence the visual quality of the fruit, but not in production. With the growth of the fruit, infections can affect negatively the production, leading to an increase in fruit drop
The citrus (Citrus spp.) black spot, caused by Guignardia citricarpa produces lesions on the fruit that depreciate the domestic market and to restrain them for export. The great period of susceptibility of the fruits in addition to the fact that the pathogen causing latent infection of complicates the understanding of the incubation period of the disease. The aim of this study was to determine the incubation period of the citrus black spot is constant or variable, inoculating fruits of 'Valência' orange at the different phenological stages and was also given the importance of copper fungicide sprays, stage of petal drop and up to seven months in the control of citrus black spot The results indicate a negative linear relationship between the incubation period of the CBS and the diameter of the fruits inoculated. The incubation period observed in fruits inoculated still immature (2,0, 2,5 and 3,0 cm diameter) was long, smaller in diameter occurred around 266 days, and fruits already developed (5,0 and 7,0 cm diameter) for the disease expression was shorter in diameter occurred in approximately 30 days. The citrus black spot has a variable incubation period depends on the phenological stages in which fruit is inoculated. The concentration of inoculum of Guignardia citricarpa not interfere with the incubation period of the disease. Regarding the incidence of CBS, even with six copper sprays every 28 days, 53.3% of the fruit expressed disease symptoms. For severity, there is no difference in response between treatments. Therefore, the data showed that early infections influence the visual quality of the fruit, but not in production. With the growth of the fruit, infections can affect negatively the production, leading to an increase in fruit drop
Descrição
Palavras-chave
Laranja, Guignardia citricarpa, Infecção quiescente, Citrus sinensis, susceptibility, Quiescent infection, Incidence, Severity, production
Como citar
AGUIAR, Ronilda Lana. Período de incubação de Guignardia citricarpa em frutos de laranja ‘Valência’ e importância das pulverizações de cobre no controle da mancha preta. 2011. vii, 36 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2011.