We deposit water droplets onto isopropyl alcohol (IPA)–metal nanoparticle mixtures to trigger Marangoni flows that drive interfacial particle self-assembly, and we use scaling analysis to uncover the mechanism and enable morphology control for practical applications.

High-speed imaging shows that a single raindrop striking infected wheat liberates thousands of Puccinia triticina spores and simultaneously forms an air vortex ring that lifts and carries them away. The vortex increases spores’ height and range, and a characterized model predicts their trajectories, implying raindrop impacts can transport pathogens beyond the leaf boundary layer for long-distance spread.