Epidemiologia de ferrugem e da cercosporiose em cafeeiro irrigado e fertirrigado
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Data
2001
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Universidade Federal de Lavras
Resumo
A irrigação e a fertirrigação são práticas muito utilizadas para a expansão da cultura em regiões promissoras limitadas por baixas precipitações pluviométricas ou chuvas mal distribuídas, visando garantir boa produtividade. No entanto, pouco se conhece a respeito de sua influência sobre a cultura, ambiente e patógenos. O presente trabalho teve como objetivo, avaliar o efeito da irrigação sob sistema de gotejamento, sobre a incidência e a severidade da ferrugem e cercosporiose do cafeeiro, principais doenças causadoras de queda de produtividade, e correlacionar com o enfolhamento, produtividade e condições climáticas do local. O experimento foi conduzido em área experimental do Departamento de Engenharia Agrícola da Universidade Federal de Lavras - MG, utilizando o cultivar Acaiá Cerrado MG-1474 de três anos de idade, em espaçamento de 0,6 x 3,0 m. O delineamento experimental realizado em blocos ao acaso, foi composto por cinco parcelar, que receberam lâminas de irrigação de 0,40, 60, 80 e 100% da evaporação do tanque Classe A (eca), três subparcelas com parcelamentos de adubação nitrogenada e potássio em 3,6 e 9 vezes, e quatro repetições. As parcelas foram compostas por 30 plantas, distribuídas em três fileiras (subparceladas) de 10 plantas cada, das quais somente oito foram consideradas úteis. As avaliações de incidência e severidade da ferrugem e cercosporiose nas folhas foram realizadas em intervalos de 14 dias, por meio dos sintomas observados em 8 folhas por planta, obtidas aleatoriamente no terço médio das plantas, entre o terceiro e quarto par de folhas do ramo. Nos frutos, avaliou-se a incidência e a severidade da cercosporiose com base nos sintomas observados em 140 frutos da subparcela e 420 frutos da parcela, obtidos quando a primeira lâmina atingir o estágio de maturação foi colhida. Avaliou-se ainda, o enfolhamento das plantas, estabelecendo-se notas de 1 a 5, (de acordo com a porcentagem de enfolhamento). Os resultados obtidos das avaliações de incidência e severidade das folhas e enfolhamento, foram transformados em área abaixo da curva do progresso da doença e do enfolhamento, respectivamente, antes de serem analisados estatisticamente. Dados climáticos de precipitação (mm), temperaturas máxima, média e mínima (°C), e umidade relativa do ar (%) foram obtidos diariamente pela Estação Climatológica do campus da Universidade Federal de Lavras para correlação com as doenças avaliadas. Com base nos resultados, verificou-se que, a incidência da ferrugem não foi influenciada pelas diferentes lâminas de irrigação e parcelamentos de adubação. No entanto, houve maior severidade da ferrugem quando submetida a maiores lâminas de irrigação. Incidência e severidade estiveram correlacionadas negativamente com as lâminas em todos os tratamentos de lâminas. Quanto à cercosporiose, a incidência e a severidade foi maior tanto nas folhas como nos frutos, quanto menor a lâmina de irrigação aplicada à cultura. A correlação entre a incidência da cercosporiose nos tratamentos de irrigação (40,60,80 e 100% ECA) e todas as variáveis climáticas, com exceção da umidade relativa foi significativamente negativa. As doenças ferrugem e cercosporiose, ocorreram com maior intensidade durante os meses de junho/julho e maio/junho, respectivamente. Houve ainda, correlação positiva entre o enfolhamento e a produtividade. Observou-se maior produtividade em plantas com maior enfolhamento, submetidas a maiores lâminas de irrigação. Os parcelamento de adubação, isoladamente não influenciaram as variáveis analisadas, porém, interagindo com a máxima lâmina de irrigação (100%) ECA), obtiveram maior produtividade da cultura e severidade da cercosporiose na folhas quando a adubação foi parcelada em 3 vezes. Sob a lâmina 0% ECA, ocorreu maior incidência da cercosporiose nos frutos quando a adubação foi realizada em 3 ou 9 parcelamentos.
Irrigation and fertirrigation are practices widely utilized for expanding the crop into promising regions limited by low rainfalls or badly distributed rains, aiming to warrant good yields. However, little is known about their influence on crop, environment and pathogens. The order of the present work was carried out to evaluate the effect of irrigation and fertirrigation under a dripping system in the inicidence and severity of rust and brown eye sport, wich is the diseases causing yield fall, and correlate with leafing, both yield and climatic conditions of the place. The experiment was carried out in an experimental area of climatic conditions of the place. The experiment was carried out in an experimental are of the Agricultural Engineering department of the Universidade Federal de Lavras-MG, utilizing the cultivar Acaiá Cerrado MG 1474 of three years in a 0,6 x 3,0 m spacing. The experimental desing accomplished in randomized blocks consisted of five plots which were given irrigation depths of 0, 40, 60, 80 rand 100% of the evaporation of the Class A pan (ECA), three subplots of nitrogen and potassium fertilization in 3, 6 and 9 splits, and four replicates. The plots consisted of 30 plants, allocated into three rows (subplots) of 10 plants each, from which only eight were considered useful. The evaluations of inicidence and severity of rust and brow eye spot on the leaves were accomplished in 14 days intervals through the symptoms observed on 8 leaves per plant, randomly obtained on the medium third of the plants between the third and fourth pair of leaves on the branch. The incidence and severity of brow eye spot on the fruit was evaluated on the basis of the symptoms observed on 140 fruits of the subplot and 420 fruits of the plot, obtained when the first depth to reach the maturation stage was harvested. The leafing of the plants was still evaluated, by establishing scores of 1 to 5 according to the percentage of leafing, 1 being (0 to20%), 2 (21 to 40%) 3 (41 to 80%) and 5 (81 to 100% of leafing). The results obtained from the incidence and severity evaluations of the leaves and leafing were transformed into area below the progress curve of rainfall (mm), maximum, medium and minimum temperature (ºC) and air relative humidity (%) were obtained daily from Universidade Federal de Lavras campus weather station for correlation with the diseases evaluated. On the basis of the results, it was found that the incidence of rust was not influenced by the different irrigation depths and fertilization splits. Nevertheless, there was a greater severity of rust when submitted to higher irrigation depths. Incidence and severity were correlated negatively with the climatic variables in all the treatments of depth applied to the crop. The correlation between the incidence of brown eye spot in the irrigation treatments (40,60,80 and 100% ECA) and all the climatic variables with the exception of relative moisture, was significantly negative. The diseases rust and brown eye spot occurred with grater intensity during the months of June/July and May/Jun, respectively. There was still a positive correlation on plants with a greater leafing submitted to higher irrigation interacting with the maximum irrigation deph (100% ECA), the presented increased yield of the crop and severity of brown eye spot on the leaves when the fertilization was splitted into three times. Under 0% depth ECA, the highest incidence of brown eye spot on the fruits occurred when the fertilization was the accomplished in 3 or 9 splits.
Irrigation and fertirrigation are practices widely utilized for expanding the crop into promising regions limited by low rainfalls or badly distributed rains, aiming to warrant good yields. However, little is known about their influence on crop, environment and pathogens. The order of the present work was carried out to evaluate the effect of irrigation and fertirrigation under a dripping system in the inicidence and severity of rust and brown eye sport, wich is the diseases causing yield fall, and correlate with leafing, both yield and climatic conditions of the place. The experiment was carried out in an experimental area of climatic conditions of the place. The experiment was carried out in an experimental are of the Agricultural Engineering department of the Universidade Federal de Lavras-MG, utilizing the cultivar Acaiá Cerrado MG 1474 of three years in a 0,6 x 3,0 m spacing. The experimental desing accomplished in randomized blocks consisted of five plots which were given irrigation depths of 0, 40, 60, 80 rand 100% of the evaporation of the Class A pan (ECA), three subplots of nitrogen and potassium fertilization in 3, 6 and 9 splits, and four replicates. The plots consisted of 30 plants, allocated into three rows (subplots) of 10 plants each, from which only eight were considered useful. The evaluations of inicidence and severity of rust and brow eye spot on the leaves were accomplished in 14 days intervals through the symptoms observed on 8 leaves per plant, randomly obtained on the medium third of the plants between the third and fourth pair of leaves on the branch. The incidence and severity of brow eye spot on the fruit was evaluated on the basis of the symptoms observed on 140 fruits of the subplot and 420 fruits of the plot, obtained when the first depth to reach the maturation stage was harvested. The leafing of the plants was still evaluated, by establishing scores of 1 to 5 according to the percentage of leafing, 1 being (0 to20%), 2 (21 to 40%) 3 (41 to 80%) and 5 (81 to 100% of leafing). The results obtained from the incidence and severity evaluations of the leaves and leafing were transformed into area below the progress curve of rainfall (mm), maximum, medium and minimum temperature (ºC) and air relative humidity (%) were obtained daily from Universidade Federal de Lavras campus weather station for correlation with the diseases evaluated. On the basis of the results, it was found that the incidence of rust was not influenced by the different irrigation depths and fertilization splits. Nevertheless, there was a greater severity of rust when submitted to higher irrigation depths. Incidence and severity were correlated negatively with the climatic variables in all the treatments of depth applied to the crop. The correlation between the incidence of brown eye spot in the irrigation treatments (40,60,80 and 100% ECA) and all the climatic variables with the exception of relative moisture, was significantly negative. The diseases rust and brown eye spot occurred with grater intensity during the months of June/July and May/Jun, respectively. There was still a positive correlation on plants with a greater leafing submitted to higher irrigation interacting with the maximum irrigation deph (100% ECA), the presented increased yield of the crop and severity of brown eye spot on the leaves when the fertilization was splitted into three times. Under 0% depth ECA, the highest incidence of brown eye spot on the fruits occurred when the fertilization was the accomplished in 3 or 9 splits.
Descrição
Dissertação de Mestrado defendida na Universidade Federal de Lavras
Palavras-chave
Ferrugem do cafeeiro Cercosporiose Epidemiologia Café Irrigação Fertirrigação Hemileia vastatrix Cercospora coffeicola, Coffee leaf rust Brown eye spot Epidemiologe Coffee Irrigation Fertirrigation Hemileia vastatrix Cercospora coffeicola
Citação
Boldini, Juliana Moraes. Epidemiologia de ferrugem e da cercosporiose em cafeeiro irrigado e fertirrigado. Lavras : UFLA, 2001. 67p. (Dissertação - Mestrado em Agronomia, área de concentração: Fitopatologia). Orientador: Paulo Estevão de Souza. T 633.7398 B687e 2001