Resistência de Cercospora coffeicola a fungicidas

Abstract

The coffee gray leaf spot of the most important diseases of the crop, but few published studies on the etiological agent (Cercospora coffeicola) and its control. Therefore the objectives of this study were to develop a methodology for isolating the fungus C. coffeicola, verify the existence of the isolates with low sensitivity / resistance to the main fungicides used in commercial fields, test the efficiency of spray programs and the influence of the antibiotic kasugamycin, widely used for control of bacterial blight on the C coffeicola and its effect on the sensitivity of fungicides. Therefore, a method that allowed the isolation of 70 isolated from the pathogen was, developed; the new technique is called Pipette Technique. Tests with spraying programs showed inefficiency of the programs (with two applications of Azoxystrobin and Cyproconazole, December and February, and the third application with Cyproconazole April) and results ‘in vitro’ Cyproconazole was the only active ingredient present some degree of resistance to the IC50 variables, CIM and ICM. Finally it was concluded that the Kasugamycin has moderate action fungitoxic the fungus C. coffeicola, although its use for this purpose is not regulated. However its use in commercial fields should be avoided because exposure to it confers reduced sensitivity to fungicides of the group of Triazoles (DMI's).