Next time you pass a wheat field on a fresh early morning, you may wish to state “gesundheit.”

That’s because some ill plants can “sneeze”— shooting out small water beads loaded with pathogens, researchers report June 19 in the Journal of the Royal Society User Interface In wheat plants contaminated with the fungi Puccinia triticina, coalescing dew beads flew far from the leaves they were on and brought fungal spores with them, experiments revealed. The pathogen, which triggers a devastating illness referred to as leaf rust, may then have the ability to contaminate other wheat plants ( SN: 9/25/10, p. 22).

The flinging result, which can occur on healthy plants too, is the outcome of a peculiarity of fluid characteristics: When 2 water drops join, surface area stress is launched and transformed into kinetic energy that can toss the fluid away.

It’s a “surface area stress catapult,” states mechanical engineer Jonathan Boreyko of Virginia Tech in Blacksburg. The result happens just on exceptionally water-repellent, or superhydrophobic, surface areas, like the leaves of particular plants, consisting of wheat ( SN: 3/1/03, p. 132).

The drops can leap a couple of millimeters– high adequate to leave the layer of still air that surrounds each leaf, so that a mild breeze might bring the water and spores to other plants, Boreyko and coworkers report. The catapulting result was understood to take place on other superhydrophobic surface areas, however this is the very first time it’s been recommended that it assists transfer illness.

Comprehending how leaf rust spreads might be crucial for managing it. If “sneezing” ends up being an essential source of transmission, plants might be sprayed with a finishing to make them no longer superhydrophobic, for instance, Boreyko states.

WATER FOUL In a peculiarity of fluid characteristics, dewdrops on healthy wheat plants and ill ones go flying after 2 drops coalesce and surface area stress is launched. Water catapulted from unhealthy plants can take pathogens along for the trip, such as fungal spores that trigger an infection called leaf rust (orange in the unhealthy plant clip).