Wheat Spike Diseases Under Changing Climatic Scenario with Special Emphasis on Fusarium Head Blight

Fusarium head blight (FHB) poses a significant threat to global food security by reducing yields, diminishing grain quality, and causing mycotoxin contamination. This chapter synthesizes current knowledge on the aetiology, epidemiology, and management of FHB, with emphasis on climate-driven disease dynamics. FHB is caused by a complex of Fusarium species, among which Fusarium graminearum is the most aggressive and widely distributed, exhibiting adaptability across diverse agroecological zones. Environmental factors such as temperature, humidity, and rainfall during anthesis are critical for host infection, pathogen dispersal, and survival, thereby increasing epidemic risk under climate variability and conservation agriculture. Mycotoxin production, including deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEN), exacerbates the socio-economic impact by compromising food and feed safety. In India, FHB is transitioning from a minor to a potentially significant disease due to shifts in climate, agronomic practices, and pathogen aggressiveness, highlighting the need for enhanced surveillance and targeted interventions. Considerable variability in pathogen populations and aggressiveness, coupled with limited genetic resistance in current germplasm, presents persistent challenges. Integrated disease management strategies, including cultural practices, deployment of resistant cultivars, fungicide application, biological control, and forecasting systems, are assessed, with attention to their complementary roles and inherent limitations. Advances in molecular breeding, quantitative trait locus (QTL) mapping, genomic selection, and gene editing offer promising avenues for developing durable resistance. However, challenges remain due to the polygenic nature of resistance and genotype-by-environment interactions. A climate-resilient, multidisciplinary approach integrating epidemiology, genomics, and sustainable management practices is essential to address the escalating threat of FHB in wheat production systems.