Splash down
Farmers have long noted a correlation between rainstorms and disease outbreaks among plants. Fungal parasites known as “rust” can grow particularly rampant following rain events, eating away at the leaves of wheat and potentially depleting crop harvests. While historical weather records suggest that rainfall may scatter rust and other pathogens throughout a plant population, the mechanism by which this occurs has not been explored, until now. In a paper published in the Journal of the Royal Society Interface, a team from MIT and the University of Liege, in Belgium, presents high-speed images of raindrops splashing down on a variety of leaves coated with contaminated fluid. As seen in high resolution, these raindrops can act as a dispersing agent, in some instances catapulting contaminated droplets far from their leaf source. The researchers observed characteristic patterns of dispersal, and found that the range of dispersal depends on a plant’s mechanical properties — particularly its compliance,...