Thursday, September 22, 2011

Leave It Be!

Last week, as we were reaching into the branches of our now-montrous tomato plants, we jumped back...our hands brushed past this thing and gave us a startle:


Once we (okay, mostly I) got over the initial 'ewww' factor, I took a close look. I had read about this very thing months before, when fellow gardeners were having outbreaks of tomato hornworm. The hooked horn hanging from this blackened carcass is a dead-giveaway...this thing had once crawled around our tomato plants looking something like this:

tomato hornworm larva  (12646 bytes)

Oh, eww. I'm all about nature, but these things really, really make me grimace. Probably mostly because I know that they are capable of destroying whole crops of tomatoes by eating all the leaves and stems from the plants. And on top of that, they are UGLY.

I had carefully looked for hornworms after Aunt Casey (fellow gardener and my sister-in-law) sent me pictures of some particularly huge and horrible looking ones in her tomatoes. At the time, I didn't find any. I did internet searches to arm myself with knowledge should we have an outbreak. We never did have an outbreak of them, and even after finding this single, very dead hornworm, I haven't found another. I have been a little more cautious (or should I say, squeamish?) as I reach into the plants, though, because the thought of brushing up against a hormworm really makes me squirm. The kids have been hoping to see a live one, but I am really okay with just the single, dead, mummy-looking specimen.

So, why does our mummy hornworm have little white caccoons all over it?

The caccoons are future braconid wasps.
Polistes wasp

They have a nasty way of laying their eggs on hornworms..eggs that hatch into hungry larva that burrow into the hornworm and eat its insides before making a caccoon. Eww, again. But this time, also...HOORAY! Anything to save the tomatoes! Apparently, this wasp not only likes hornworm larvae, but also aphids, cabbage looper, other garden caterpillars. Eggs from braconid wasps are even sold commercially, they are so beneficial for pest control in the garden.
I've always been a little afraid of wasps, but this knowledge--along with the fact that wasps are also amazing pollinators--makes me respect them a bit more. That doesn't mean I won't scream when one hovers and zooms in close to my face...but maybe I will scream less loudly?
The title of this post is LEAVE IT BE, and if you come upon a hornworm that's been renovated into a wasp nursery, that is what you should do. You want those wasps to live and thrive in your garden, as fellow bodygaurds to your tomatoes!

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