Organic Pest Control and Tomato Hornworms

OK, this disgusting beast is the well-known and reviled tomato hornworm.

One year, we went away on 4th of July weekend. Upon returning, we discovered all three of our tomato plants had ben ravaged. The culprit, presumably, was the lone hornworm we found nestled in the leaves, given away by its audible munching.

We maliciously put it in the bird feeder.

Earlier this summer Jeff found this guy on one of the tomato plants. He’d already found one, and had dispatched it quickly to hornworm heaven with a truly sickening crunch underfoot.

I convinced him to let this one live. I’ll tell you why.

See those nasty white things on his back? Those are the cocoons of braconid wasps. They are already feeding on the internal organs of this hornworm; he is not going to be doing any more damage to my tomato plants.

By allowing this hornworm to live long enough to nourish those wasps, I am in effect raising an anti-hornworm army, ensuring that any others will be killed as they leave their cocoons or similarly parasitized.

Of course, if I do find any more adults that do not bear cocoons on their backs, I’ll go ahead and give it to the blue jays as a treat. They love ’em.

I came by this information in Douglas Tallamy’s Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens, and it was a real eye-opener for me.

I suspect, however, that it may be common knowledge to the experienced gardener. Did you already know about this? Are there any other “pests” I should be leaving well-enough alone?