Tuesday, June 8, 2010

cabbage worm invasion

The heart of organic gardening goes beyond a desire for natural, pesticide- and chemical-free food. What it ultimately encompasses is the belief that all creatures have a purpose in this world and each is essential to the interdependent food web, and a loss of any single species of creature would throw the environment out of balance. Reaching the "end," which equates to a prosperous garden and wholesome food, should not justify an inhumane or destructive means. Each creature is precious, and no matter how annoying to our gardening activities, must be dealt with respectfully.

Last night when I checked on my lettuce plants, they were perfect. I woke-up this morning to sheared and holey leaves and a scene of destruction:

It amazes me how fast these sneaky creatures work!

Hidden in the leaf vein, this big guy was well-concealed.

The smallest larvae were found on the underside of the leaf. This is the first place you should look when searching for the culprits. It's a good hiding spot for them, and a common area for the adult female to lay the eggs.

I've found the method that best satisfies me in my quest for completely organic gardening is to manually remove the larvae from the plants and take them to the other side of my yard. I'm still a little squirmish about touching them, so I use a narrow popsicle stick to scoop them up, then drop them into a cup. For the past few years that I've done this, I have not found repeat offenders. Next year I may grow a special "veggie butterfly garden" just for them, far away from our food, since I know that by moving them to the other side of the yard, I am essentially sentencing them to death by starvation.

How do butterflies and moths find the correct place to lay their eggs? I have only three trial lettuce plants in my backyard. How on earth did they locate them within the sprawl of suburban grass in my neighborhood?

"Because each species of butterfly or moth is adapted to eat specific species of plants, females are very selective about where they lay their eggs. These plants are called “host plants.” The female butterfly instinctively recognizes the correct leaf shape, color, odor, taste, and appearance of this host plant. Once satisfied, she lays her eggs, coating them with an adhesive that fastens them to the leaf." (http://www.flmnh.ufl.edu/education/guides/butterfly-guide.pdf)

But more specifically, the December 1985 issue of The Quarterly Review of Biology contains the essay "Communication of Insects," which goes into further detail on how larvae select suitable food for themselves, outside of the proper egg-laying site by the female moth:

"Insects recognize food and food plants by means of tactile stimuli (e.g. smooth and hairy surfaces vs. rough and hairy surfaces) and by nonvolatile chemical cues. The latter require for initial recognition some contact with the plant's surface by the antennae or by the chemosensory apparatus associated with the mouthparts. The initial contact is followed by sampling the chemicals by biting the plant."

Once the larva breaks the surface of the plant, amino acids, steroids, salts, sugars and other complex chemicals are released. The caterpillar has specific gustatory receptors to respond to them. This is how they know which food they should be eating. In addition to biting, simply tasting the plant food source can give feeding clues:

"Host-plant selection requires biting to release the soluble signals, whereas cuticular cues can be tasted directly from the surface. [Larvae and adult moths] can identify ovipositional stimulants, feeding stimulants, antifeedants, repellents, and toxins."

Just a little bit of research a day is all it takes to gain a greater appreciation of the common things in our lives that we see everyday but don't have any personal knowledge about.

Humans have sought to harness and control the wilderness since the beginning of time. But ruling over nature can have harmful, long-lasting, and irreversible effects. It's much better for everyone involved--meaning all of the creatures that live and breathe on this blue earth--for us to try and gain a greater understanding of other species, which will in turn bring about environmental harmony. To do otherwise will bring destruction for all, including us. We must learn to reconnect with our natural world.


walk2write said...

I'm with you on the squeamish thing. Some of those caterpillars can actually sting with bristles so it's a good idea not to handle them without gloves or something to pick them up. Besides, if you want them to live, bacteria and other nasties on our hands would probably do them in. Great post, CM!

Clementine Moonflower said...

Thank you! I'm getting back into blogging again. I'm such a fickle blogger. I have tons of photos just crying out for a home.

I know this entry is a little on the dry side, but I'm trying to focus my anger about the oil spill into something productive.

troutbirder said...

I'm with you. As a novice gardener several decades back I subscribed to Oranic Gardening (by Rodale Press) Your cabbage worm crises shows the determination it takes in face of wanton unprovoked and premediated destruction to maintain your high moral, ethical, and environmental standards. Praise Be you remained strong!!! Yes... I did not find this post too much on the "dry side" at all....

Clementine Moonflower said...

It was tough, but I had to do it! It was the right decision. If I can weather a cabbage worm crisis, I can weather all. Oh, and about the moral, ethical, etc...I still can't convince my husband to stop using paper towels, and I have three containers of Secret (a.k.a. chemicals) deodorant sitting on my vanity in the bathroom.

I know that publication! Rodale makes some pretty nice magazines.

Oh and W2W, I'm totally in agreement about not touching the caterpillars. I've read about how irritating they can be.

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