Paper Title
QOI Fungicide Resistance in Cercospora Coffeicola: A Comprehensive Study in the Major Coffee Producing Region in Brazil

Abstract
Brown eye spot, caused (Cercosporacoffeicola) is a significant disease affecting coffee (Coffea arabica) in Brazil, where resistant cultivars are unavailable. Management depends on fungicides, particularly quinone outside inhibitors (QoIs), which can select pathogens for resistant with continuous use. This study aimed at mapping the sensitivity of C. coffeicola to QoIsin the major coffee producing region in Brazil (Minas Gerais State), evaluate the in vitro sensitivity to the fungicide pyraclostrobin, and characterize isolates for resistance mutations using PCR.A total of 224 single-spore isolates were collected from 26 municipalities in Minas Gerais, with 16 isolates tested for in vitro sensitivity and 65byPCR assay. The EC50 for pyraclostrobin classified the isolates:high resistant (76,493 – 146,417 µg/mL); resistant (1,155 – 17,167 µg/mL) and moderately resistant (0,121 – 0,568 µg/mL). The G143A mutation, associated with QoI resistance, was found in 95,38% of the isolates, while the F129L mutation was not detected.The results indicate a widespread presence of QoI resistance in C. coffeicola populations in Brazil, highlighting the necessity for continuous monitoring to refine management strategies and ensure the effectiveness of chemical control measures for coffee diseases. Keywords - Brown Eye Spot, Pyraclostrobin, Quinone Outside Inhibitors, Cytb Gene,G143A