Published on 2019-06-17T09:26:51Z (GMT) by

We show that condensation growing on wheat leaves infected with the leaf rust fungus, <i>Puccinia triticina</i> is capable of spontaneously launching urediniospores off the plant. This surprising liberation mechanism is enabled by the superhydrophobicity of wheat leaves, which promotes a jumping-droplet mode of condensation powered by the surface energy released from coalescence events. We found that urediniospores often adhere to the self-propelled condensate, resulting in liberation rates of approximately 10 cm<sup>−2</sup> h<sup>−1</sup> for leaves infected with rust. Urediniospores were catapulted up to 5 mm from the leaf’s surface, a distance sufficient to clear the laminar boundary layer for subsequent dispersal even in gentle winds.