University of Missouri researchers, Dr. Heidi Appel and Dr. Rex Cocroft are collaborating on a project that is looking at how when insects such as caterpillars are eating their host plants, they produce a vibrational noise like crunch crunch and the plant responds to the sound. It turns out that if the crunching sound is recorded and then played back to plants, even in the absence of the caterpillar, the plants will generate chemicals that the insects don't like as a defense. I asked these researchers if that would apply to farmers crops. "We are very interested in someone finding a practical application. But our work is really pretty fundamental plant biology. I guess what I would add to it is the kind of questions that need to be answered in order to force somebody to be able to do what you're talking about are ones that we are interested in in our research. So we are interested in, for example, to other species of plants such as the ones you mentioned have a similar ability. We also would expect different species of plants to interact with different natural enemies which would in turn produce different vibrations so we might expect that what plants are tuned into would very depending on the species. So if our research were to show that, yes, other plants have this ability and that they are tuned into the acoustic signature of different natural enemies, then somebody could potentially use that in the way that you are suggesting, as a way to prime a crop plant.