Interação da luz, da temperatura e do molhamento foliar em Cercospora coffeicola e na cercosporiose em cafeeiro

Abstract

Coffee stands out as one of the most important 'commodity' produced in the country, being Brazil the largest producer and exporter. The occurrence of diseases is one of the main factors responsible for losses in the coffee fields, which occurs from the nursery to the field. Among the diseases of the coffee stands out cercospora whose adverse planting in areas with perennial crops, soils markedly evaporation and regions of high insolation and temperature reconciled to nutritional unbalance has worsened in coffee and generated significant losses. To elucidate the influence of environmental factors such as temperature, light intensity and leaf wetness on the behavior of the pathogen, disease and plant physiological variables, experiments were conducted in the Department of Plant Pathology at UFLA. To optimize the sporulation and germination of conidia of Cercospora coffeicola and enable the experiments, different conditions of temperature and light intensity were used and under such conditions, was chosen a pathogenic strain, able to sporulate and produce cercosporin. Subsequently, was studied the effect of temperature and light intensity in vitro by evaluating the rate of mycelial growth and the production of cercosporin. In vivo, was assessed the effect of such variables in the progress of the incidence and severity of the disease, the influence of the disease on chlorophyll a, b and total and physiological variables. Another study was conducted by evaluating the interaction between temperature and hours of leaf wetness in vivo, evaluating the same variables as in the previous experiment. The variables temperature, light intensity and hours of leaf wetness influence in both, the fungi and the disease.