Spore concentrations of Blumeria graminis f. sp. tritici in relation to weather factors and disease development in Gansu, China

Abstract

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is an important disease in China. In this study, airborne spore concentrations were monitored using spore samplers and real-time PCR during 2013– 2015 at three locations in Gangu, Gansu province of China. The effects of meteorological variables on spore concentration were analyzed and models were developed for forecasting dynamics of airborne conidia and disease progress. The temperature, solar radiation and rainfall were positively correlated to spore concentrations and disease development. Although there was a negative correlation between relative humidity and spore concentration, relative humidity was positively related with disease development. Stepwise regression models were obtained for predicting the dynamics of airborne conidia based on the positive degree days and accumulation of rainfall (R2 = 0.31, P < 0.01), the positive degree days (R2 = 0.16, P = 0.04) and mean temperatures (R2 = 0.24, P = 0.01) at three locations, respectively. Disease forecasting models were developed based on various meteorological variables and spore concentration, the most important variables being temperature and spore concentration. This knowledge can improve the disease forecasting of wheat powdery mildew in Gangu and help develop better disease control strategies.