Saturday, July 21, 2007

Let's get crass about frass

Tomatoes in the garden inevitably mean tomato horn worms in the garden, the larva of the hawk sphinx moth. Even though the larvae can be quite large—four plus inches—they can be darned hard to spot. In fact, I've pretty nearly had my hands on them before seeing them. What I can spot, however, are their rather large poop balls, called frass. These telltale droppings clustered under plants (underlined in white in the above photo and nicely captured in the photo to the left) let me know where to look, narrowing down the hunt considerably. Of course, nearly defoliated leaf tips help, too, as do the fruits with the ugly wounds left by a munching worm who hadn't the decency to just stay and finish the tomato before moving onto another. I try to get them before these latter signs, however, and the frass is my single best clue.

Once I find these camouflage artists, I pull them from the vine, pinch them between my fingers folded in half lengthwise and walk them down to my birds. The turkeys and the chickens are more than happy to help me rid my garden of these pests, and though it seems a rather cruel demise to be the unwitting player in a tug of war between two beaks, watching the birds chase each other, trying to steal the quarry is rather amusing. Nothing like a little farm fun at the expense of a garden pest.

There are, however, some horn worms we invite to live out their larval stage in our garden, munching on their fill of tomatoes. Why? Because they are playing host to the parasitic braconid wasp, who lays its eggs under the skin of the horn worm larva. When the eggs hatch, they will feed on the horn worm itself, turning the tomato muncher into the meal. Either way, the demise of a tomato horn worm is somewhat gruesome. Slow wasting death by parasite or speedy death by bird sport? Hmmmm....


Woody said...

Hard to see...yes, but you can hear them.

Country Girl said...

Great post. Thanks for the great info. I did a google search and did not learn as much about them as I did reading your post. That's why I love blogging! ~Kim