Impact of the G143A mutation of cytochrome b on QoI resistance, fitness, and cross-resistance patterns in Alternaria alternata from cherry

Alternaria alternata is an important fungal pathogen causing leaf spot and fruit rot diseases in a variety of crops, including sweet cherry. The development of resistance to fungicides, especially quinone outside inhibitor (QoI) fungicides, has emerged as a significant concern in managing cherry diseases. In this study, 109 A. alternata isolates collected from four geographic regions were screened for sensitivity to QoI fungicide azoxystrobin and other fungicides. Results showed that 74 isolates