Hebei province locates in the North China region of China. Winter wheat-summer maize rotation is the main cropping system. Wheat production in Hebei is important for China as it ranks third, with a growing area of 2.4 M ha and annual yield of 12~13 M tonnes. Fusarium head blight (FHB) has been a problem since the 1990’s. In the 2013-14 season, we conducted a survey to clarify the etiology of FHB in 49 fields, 29 counties of Hebei. Premature bleaching heads with browning rachis were collected and shrivelled kernels were disinfested with 70% ethanol and plated onto Peptone PCNB Agar. Fusarium-like colonies were subcultured to carnation leaf agar (CLA) and incubated under BLB light. Pure cultures were established and identified by morphological and molecular characteristics. Results showed that F. pseudograminearum was the predominant pathogen in Hebei. However five isolates from Luancheng County (N37°53′58.43″/E114°37′14.65″), Zhao County (N37°51′12.84″/E114°48′52.87″) and Fengrun County (N39°46′56.65″/E118...

On the North China Plain, one of the most water-deficient regions in China, bare fallow has been implemented over a large-scale area to conserve water during the growth season of water-intensive winter wheat since 2015. However, the effects of this bare fallow on fungal community and the occurrence of crop diseases are poorly understood. Here we measured soil chemical properties, fungal community composition, and the occurrence of crop diseases after 15 years of long-term fallow (continuous maize or soybean) and non-fallow (maize-wheat rotation; soybean-wheat rotation) cropping systems. Bare fallow during the winter-wheat growth season significantly decreased soil organic matter, available nitrogen, and phosphorus. It also changed the composition of soil fungal communities, i.e., increased relative abundances of some potentially pathogenic species of Lectera, Fusarium, and Volutella but decreased beneficial Cladorrhium and Schizothecium. Meanwhile, the epidemic tendency of maize diseases changed correspondingly: the disease index of southern corn leaf blight and maize brown spot increased, but the incidence of stalk rot decreased compared with the non-fallow system. Soybean diseases were very mild regardless of the cropping system during the total experimental period. Network analysis demonstrated that the soil fungal diversity associated with maize diseases was affected by the decreased soil organic matter and available nitrogen and phosphorus. Our results suggest that bare fallow in the winter-wheat season affected the soil chemical properties, fungal community, and the occurrence of maize fungal diseases.