Brazil is the world's largest coffee producer. Brown eye spot (BES) (Cercospora coffeicola) is a major crop disease that can cause 15-30% production losses and decrease the coffee beverage quality. Although the influence of this disease on beverage quality has been studied, diagrammatic scales for assessment of the disease severity in berries are still unexplored. Thus, this study has developed and validated diagrammatic scales to assess the severity of BES. Two diagrammatic scales were designed to assess the disease in berries, which can be yellow or red depending on the cultivar. The scale of yellow berries had nine grades: grade 0: 0%; 1: 0

Brown eye spot (BES—Cercospora coffeicola) is a major disease of coffee, and its occurrence is affected by water supply and nutritional balance. Little is known about the effect of phosphorous (P) on coffee fields under irrigation. Thus, this study evaluated the effect of the interaction between different water application levels and phosphorus levels (5 irrigation levels × 4 phosphorus levels) on the intensity of this disease. The area under the incidence progress curve (AUIPC) was calculated and subjected to analysis of variance. The progress curve of the average incidence of BES varied in both evaluation years. In Year 1 (November 2011 to December 2012), the incidence peaked on August 12, 2012 (22.45%), while in Year 2 (January 2013 to January 2014), the incidence reached its highest level on September 12, 2013 (16.29%). The exponential nonlinear model was adjusted for the two years. There was an interaction between irrigation and phosphorus levels on October 07, 2012. The incidence interacted significantly with the harvest dates. On the first evaluation date, an increase in phosphorus levels at shallower irrigation depths and an absence of phosphate fertilizer at higher irrigation levels caused higher incidences.

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ABSTRACT:This study aimed at assessing the interaction of potassium (K) and boron (B) in the coffee rust intensity in a nutrient solution. The experiment which was performed in a greenhouse was set up in the randomized complete block design (DBC) with four replicates. The experimental unit involved a single vase with two Catuaí Vermelho (IAC 144) cultivars. The treatments included five doses of boron (0.05, 0.50, 1, 2 and 4 mg L -1 ) and five of potassium (4.0, 5.0, 6.0, 7.0 and 8.0 mmol L -1 ), totaling to 25 treatments in a factorial variance analysis. All the coffee seedling leaves were inoculated with Hemileia vastatrix. For the next 24 hours, the vases were covered with a black plastic bag, and left in the greenhouse to ensure favorable conditions for the fungal infection. A significant interaction was observed between the potassium (K) and boron (B) nutrients in coffee rust intensity. As the boron dose increased from 0.05 to 2.0 mg L -1 , the coffee rust intensity was observed to rise. From the 0.50 mg L -1 dose of B a drastic drop in the dry plant mass was observed, which reached zero index at the highest boron dose due to phytotoxicity. ), totalizando 25 tratamentos em esquema fatorial de análise de variância. A inoculação foi realizada em todas as folhas das mudas de cafeeiro até o ponto de escorrimento. Posteriormente, os vasos foram cobertos com saco plástico preto por 24 horas, permanecendo na casa de vegetação com o objetivo de proporcionar condições adequadas para o fungo penetrar e iniciar o processo de infecção. Ocorreu interação significativa entre os nutrientes potássio (K) e boro (B) na intensidade da ferrugem do cafeeiro. A partir da dose de 0,05 até 2,0 mg L -1 de B foi observado aumento da intensidade da ferrugem do cafeeiro. A partir da dose 0,50 mg L -1 de B houve redução drástica da massa da planta seca, atingindo índice zero na maior dose de B, devido a fitotoxidez. Termos para indexação:Hemileia vastatrix, nutrição de plantas, potássio, boro.