Pathogenicity of Bipolaris oryzae isolated from banana to different plant species

Bipolaris oryzae is a fungal plant pathogen that can affect a wide range of economically important crops and cause severe damage. Crop rotation practices that are friendly to the environment and ecosystems have attracted considerable attention as an efficient way to reduce pathogen propagules and disease incidence. The identification of nonsusceptible or nonhost plants is the basis of successful crop rotation. In August 2023, B. oryzae was first reported to cause leaf spots on banana plants (Musa acuminata AA Pisang Mas cv. Mas) in China and worldwide. The average percentage of the leaf area covered by lesions ranged from 6 to 15% and tended to increase. In this study, the potential of cross-infection of different plant species with B. oryzae isolated from banana was evaluated via an in vitro inoculation method in the laboratory under controlled conditions. Detached leaf inoculation assays revealed that among 47 plant species belonging to 26 plant families, 46 and 37 were susceptible to B. oryzae to various degrees in the wounding and nonwounding treatments, respectively. Detached fruit/bulb/tuber/root tuber inoculation assays revealed that among 46 plant species belonging to 23 plant families, 43 and 15 were susceptible to B. oryzae to various degrees in the wounding and nonwounding treatments, respectively. Among all the plant species tested, mango, tomato and kidney bean presented symptoms of infection on both leaves and fruits in the wounding and nonwounding treatments. Pepper leaf was highly susceptible and susceptible to B. oryzae in the wounding and nonwounding treatments, respectively. The fruit of bitter gourd was highly susceptible to B. oryzae in both the wounding and nonwounding treatments. Onion bulb was susceptible to B. oryzae in both the wounding and nonwounding treatments. This study is the first to report the pathogenicity of B. oryzae isolates from banana plants in China to different plant species tested under controlled conditions.