Pathogenicity evaluation of Cytospora species in 13 apple (Malus domestica) varieties and wild apple (Malus sieversii) in Xinjiang, China

Abstract Apples are a popular fruit worldwide and are cultivated in the Xinjiang Uygur Autonomous Region (XUAR) in China. Cytospora canker disease is a serious problem in the apple industry in China. Pathogenicity of all historically recorded Cytospora species from Malus hosts was tested on the leaves and breaches of 13 varieties of apple ( Malus domestica ) and wild apple ( Malus sieversii ). Cytospora leucosperma and Cytospora pruinopsis were the most aggressive pathogens on apple and wild apple trees in Xinjiang. Meanwhile, Cytospora leucostoma , Cytospora nivea and Cytospora parakantschavelii were the least aggressive. In addition, Fuji and Golden Delicious were the most Cytospora canker disease‐resistant apple varieties and are recommended for future promotion. However, Sitagan and Erzizi were readily infected by Cytospora . Our findings provide a theoretical basis for field disease epidemic monitoring and tailoring disease prevention and control strategies based on the disease resistance of the variety and the aggressiveness of the pathogen.