Effects of Climate Change on Epidemics of Powdery Mildew in Winter Wheat in China

Abstract

Powdery mildew is a highly destructive winter wheat pathogen in China. Since the causative agent is sensitive to changing weather conditions, we analyzed climatic records from regions with previous wheat powdery mildew epidemics (1970 to 2012) and investigated the long-term effects of climate change on the percent acreage (PA) of the disease. Then, using PA and the pathogen’s temperature requirements, we constructed a multiregression model to predict changes in epidemics during the 2020s, 2050s, and 2080s under representative concentration pathways RCP2.6, RCP4.5, and RCP8.5. Mean monthly air temperature increased from 1970 to 2012, whereas hours of sunshine and relative humidity decreased (P < 0.001). Year-to-year temperature changes were negatively associated with those of PA during oversummering and late spring periods of disease epidemics, whereas positive relationships were noted for other periods, and year-to-year changes in relative humidity were correlated with PA changes in the early spring period of disease epidemics (P < 0.001). Our models also predicted that PA would increase less under RCP2.6 (14.43%) than under RCP4.5 (14.51%) by the 2020s but would be higher by the 2050s and 2080s and would increase least under RCP8.5 (14.37% by the 2020s). Powdery mildew will, thus, pose an even greater threat to China’s winter wheat production in the future.

Predicting plant disease epidemics from functionally represented weather series

“…Twelve models were built upon previously reported logistic regression (lr) models with variables summarizing weather in fixed-length windows near wheat anthesis (flowering) [14]. Six of these 12 lr models (1,2,3,5,15,17) were focused on pre-anthesis conditions, whereas the other six models (7,8,9,11,12,13) targeted post-anthesis conditions. Six penalized scalar-on-function regression (s-o-f ) models (4,6,10,14,16,18) were fit with inputs being weather times series from 120 days pre-anthesis to 20 days post-anthesis, a much longer time frame than the 30-day anthesis-centred period underlying the 12 lr models.…”

“…One defining feature of epidemiology is the pursuit of successfully predicting epidemic outbreaks or disease occurrences before they are realized. Weather impacts diseases; many animal, plant and human diseases are driven by weather, and epidemiologists are often interested in understanding how disease outbreaks are correlated with weather patterns, especially in a changing climate [1,2]. Epidemiologists may be interested in a static endpoint (disease has occurred or not by a given time, or disease intensity has exceeded a threshold defined in terms of impact), or they may be interested in following the progression of disease occurrences over time in relation to weather, in which case the endpoint is now dynamic.…”

Evaluation of resistance to powdery mildew and identification of resistance genes in wheat cultivars

“…Recently, powdery mildew has become more significant with increased use of nitrogen fertilizer, changes in irrigation, and the increase of global average temperature [17]. Therefore, cultivars become susceptible more quickly under the high disease pressure and more rapid changes of virulence in the pathogen population.…”

“…In our previous study, resistance to stem rust in main wheat cultivars of the region was also studied [22,24]. In recent years, the epidemic level of powdery mildew has been increasing in Yunnan [17]. Therefore, this study was carried out to determine the level of seedling resistance to powdery mildew and to identify Pm genes in wheat cultivars use molecular markers.…”

Virulence and diversity of the Blumeria graminis f. sp. tritici populations in Lithuania and Southern Ukraine

“…Currently it is more dangerous than any other wheat diseases for this region (Zeng et al, 2014;Ma et al, 2015;Shen et al, 2015;Mwale et al, 2017). Some researchers predict powdery mildew to become more important in the future because of the climate change, which will provide more favourable conditions for the development of the disease (Tang et al, 2017). Because of the pathogen's ability to evolve and overcome host resistance and in order to prevent large-scale epidemics, continual research and monitoring of virulence is necessary.…”