ABOVE: Air-vortex dispersal of a plant pathogen
PHOTO COURTESY OF HYUNGGON PARK, VIRGINIA TECH

Small raindrops carrying fungal spores can be carried away by the wind, but researchers have now shown how larger drops too heavy to be windswept can help spread plant pathogens. The scientists have combined information gained by high-speed photography with models describing the airflow near a leaf to show how heavy raindrops can disperse dry spores from the surface of the leaf. When a big drop hits a leaf, the impact can create a “vortex ring” of air circling the raindrop to fling the spores high enough that they may catch the wind to travel further away, researchers reported February 25 in PNAS. 

S. Kim et al., “Vortex-induced dispersal of a plant pathogen by raindrop impact,” PNAS, doi:10.1073/pnas.1820318116, 2019.

Movie courtesy of S. Kim, H. Park, H. Gruszeswki, D.G. Schmale III, and S. Jung.

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