Diseases under organic cultivation of coffee (Coffea arabica L.): epidemiology and alternative control / âDoenÃas em cultivo orgÃnico do cafeeiro (Coffea arabica L.) : epidemiologia e controle alternativoâ

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

In the years of 2005 and 2006 two trials were installed in eight year old coffee plantations of the cv. Acaià MG-474-19, under organic and conventional crop systems, in Santo AntÃnio do Amparo, Minas Gerais. The progress of rust and brown eye spot diseases of coffee was assessed as a function of the effect of different biofertilizers, between December/2004 and October/2005. The nutritional status of the coffee trees was monitored in the initial, green and ripe stages of fruiting period, in the two production seasons. The highest disease intensities were observed at the control treatment, i.e., in the plots with no foliar treatment. The conventional crop system showed the highest areas under the rust and brown eye spot progress curves, allowing, therefore the association with the lowest Ca, Mg, B and Cu contents found in the leaves. These elements are directly related with the progress of the diseases as shown in previous studies. The use of the biofertilizers Agrobio and Supermagro plus weed was responsible for the lowest disease progress and highest leaf area indexes. The organic crop system showed a higher leaf area index in comparison with the conventional system for all treatments, including the control. The yield of the organic coffee trees was lower than that of the conventional system. It was observed that for the first harvest assessed there was a yield reduction of 35.8% when comparing to the yield of the best treatment (Agrobio) with the crop in the previous year, before the installation of the trials. From 2005 to 2006, there was a reduction in the crop yielding of 19.88% for the conventional system and 5.08% for the organic system. This suggests a tendency of lower effect of the diseases on the following crop of the coffees in the organic system, when comparing with the conventional system. The brown eye spot caused more defoliation of the coffee trees in the conventional system, in comparison with the organic system where the defoliation and disease incidence were lower. During the evaluation period, the nutritional status of the coffee plants in the organic system was more balanced that in the conventional system. In the organic crop system some extracts and oils of plants were tested in order to reduce the progress of the diseases on coffee plants under greenhouse (rust) and in the field (rust and brown eye spot). For the greenhouse assay, the best rust control treatments were: Agrobio, Supermagro plus weed, neem and thyme oils, pure aqueous extract of coffee leaves infected by Hemileia vastatrix or mixed with extract of huskss of coffee fruits. In the field assay, the rust progress was controlled after spraying Ecolife and thyme oil. In the assessment of brown eye spot, it was observed a significant disease reduction only after spraying EcolifeÂ.

ASSUNTO(S)

alternative control biofertilizers coffee biofertilizantes controle alternativo hemileia vastatrix cercospora coffeicola cercospora coffeicola hemileia vastatrix cafà fitopatologia

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