Fig. 4
From: Apple Valsa canker: insights into pathogenesis and disease control
Annual production and dissemination of conidia and the critical periods for preventing infection. Conidia and ascospores of Vm released from the bark surface during rainfall or high humidity are dispersed by raindrops, wind, and insects. Conidia can be produced in enormous numbers and dispersed throughout the year, especially during the flowering season (i.e., April in Shaanxi Province). Therefore, it is critical to protect the bark surface with fungicides such as tebuconazole, difenoconazole, and pyraclostrobin after the peak period of pathogen dissemination and infection during young fruit development (generally June–August)