We study the fluid mechanics of pathogen spread via raindrop impacts on plant surfaces. A high-speed camera observed both dry and wet mechanisms of pathogen spread as a drop impacts a plant leaf. Healthy and diseased (infected with the yellow-rust pathogen, Puccinia triticina) leaves were used. The presence of pathogen spores on a leaf surface makes the spreading of the contact line unstable, thereby promoting the dispersal of spore-laden satellite droplets. In addition, we observed the dry dispersal of pathogen spores from a plant surface due to air vortices and direct collisions.
This work is licensed under the Creative Commons Attribution-NonCommercial 4.0 International License. Any reuse must credit the author(s) and provide a link back to this page.