Armyworms and tomatoes are mortal enemies. A type of caterpillar, armyworms attack the leaves and fruit itself by burrowing holes, and can decimate a tomato plant overnight. But the crafty tomato isn’t defenseless. Despite not having a single brain cell, a tomato can sense when it is being attacked can call in for reinforcements to fight off the caterpillar. Whom does the tomato call? The caterpillar’s mortal enemy: a tiny parasitic wasp.
Research has found that when the caterpillar makes a wound on the tomato, the fruit immediately starts producing a chemical called jasmonic acid. This acid in turn heightens the leafy green odor of the plant, which is incredibly enticing to the wasp. The minute the wasps smell it, they come running—and then it’s war. The wasp stabs the caterpillar and lays an egg inside it; the larva hatches from the egg and literally eats the caterpillar from the inside out.
The truly amazing fact about this process is that the odor the tomato emits is not just a dog whistle for any kind of predator; it is specifically targeted to this particular type of parasitic wasp who feeds on this specific pest.
That’s one smart plant.