Spatial relationship between pre-harvest hail and the impact from the wheat streak mosaic disease complex by using remote sensing data

Wheat streak mosaic (WSM) has long been considered the most serious disease of winter wheat in the Great Plains of America. The most effective control method of the WSM disease complex is to manage volunteer wheat that is often caused by the pre -harvest hailstorms in the Great Plains. A significant WSM disease outbreak over a large geographic area in western Nebraska, United States, in the 2017 wheat growing season was studied in relation to a pre -harvest hail in 2016 using open -data Landsat and Sentinel imagery and NOAA MRMS MESH hail data. Wheat growing areas were delineated and a WSM disease severity heat map was generated based on field NDRE readings from the satellite images. The spatial relationship between the hail event and WSM disease severity was demonstrated. For this extensive hail event, the impact from the WSM disease complex extended well beyond the area of impact from the pre -harvest hail. The dramatic extent of the virus impacts beyond the area of direct hail impact demonstrated in this study, strongly reinforces the need for community -wide attention to virus management in cases where large hail streaks occur at the optimum time for the development of preharvest hail (ca. within the 3 weeks before harvest). These findings not only agree with the assumption that the pre -harvest hail damaged wheat fields serve as the source fields of mites and virus, but also improves our understanding of the spatial pattern of virus spread which can benefit growers in making management decisions. The remote sensing methods used to delineate these findings proved valuable tools in studying this relationship.