May 7th, 2009
As a child, I was fascinated by caterpillars. My brothers and I would tromp around the yard and the neighboring woods in the spring, mason jars in hand, and scour the foliage for caterpillars. And of course we had our mason jars stuffed with fun things for our captured caterpillars to do. There would be some nice grass in the bottom, a few leaves so the caterpillar would have a little something to snack on, and the obligatory stick for the little guy to crawl up on. It was excellent. And then after a couple days of captivity, if the caterpillar was still alive, we would usually tire of it and either use it as fish bait or spend some quality time with it and a magnifying glass.
As it turns out, I think that's what my dad was hoping we would do with them. Actually, I think he wished we would have killed a lot more of them than we did. Once you realize just how destructive caterpillars can be, they sorta lose their magic. They can, and often do, destroy your vegetables like cabbage and tomatoes. They also like to munch on those fresh herbs you've been growing, and they might even enjoy some of your prized flowers for dessert. If tent caterpillars are your enemy (you know, the ones that spin and live in a huge web mass in your trees), they can, in extreme cases, completely defoliate a tree. In this article, my primary focus will be on how to get rid of tent caterpillars. However, many of the suggestions, especially the ones at the bottom of this page, will work very well for getting rid of caterpillars of any flavor.
Tent Caterpillar Control
Bacillus thuringiensis. Say what? Yeah, let's just call it BT. This is simply the number one thing you can do to get rid of caterpillars. It is a bacteria that infects and kills caterpillars by destroying the lining of their guts. The great thing is it only kills caterpillars, which means there are no innocent bystanders that get wasted in the process. Since BT must be ingested to work, it is applied to foliage as a spray. BT is available online or at any garden shop. Make sure to get BTK. The "K" stands for kurstaki.
Find a good long stick. Maybe the most common way to get rid of caterpillar nests is to simply use a long stick to scrape the thing out. Just poke the stick into the nest and start spinning and scraping. It will work much better for you if you pound a few nails into the stick. In fact, if you have one, use an old broom handle. You will want to do this in the early morning or in the late evening so you will be sure that they are in their nests. Dispose of them however you wish.
Slash and burn. Another good method for caterpillar control is cutting down their nests and burning them. Use pruning shears, a hand saw, or a chain saw to disconnect the branches with the tent caterpillar nest on them from the rest of the tree. Pull the branches down to the ground and pick your favorite incineration method. We always used an empty aluminum garbage can, a bottle of charcoal lighter fluid, and a match. If you don't feel like using fire, just stomp on them for awhile.
Manual caterpillar pest control. This is another one of those methods to control caterpillars that will work for absolutely any type of pest caterpillar you find. However, I wouldn't advise it for the squeamish. Grab yourself an empty ice cream pail, coffee can, or whatever else you can find, fill it about half way up with water, squirt about a quarter cup of dish soap in it, and start picking. Just use your fingers to pluck caterpillars off of plants and toss them into the bucket to drown. Look very carefully for them. They oftentimes hide on the undersides of leaves.
Get rid of tent caterpillar egg masses. This is actually easier than it sounds. The egg masses of tent caterpillars are pretty easy to identify. See right. In the winter, go outside with a good sharp knife and search every tree you can see for the little egg masses. They can be on trunks or branches. When you find them, scrape them off and destroy them. You may also wish to bring a pair of shears with you, too, as sometimes it's easier to just snip the branch off.
Caterpillar Control Products
While I do feel strongly that BTK (mentioned above) is the best thing you can use to get rid of caterpillars, there are many other types of caterpillar pest control products available that work very well for almost any type of caterpillar. Neem oil is one of these. It is a natural oil derived from the neem tree that not only can be used as an insecticidal soap to kill caterpillars immediately, but it also tastes so bad that when sprayed on things caterpillars eat, they would rather starve than ingest anything sprayed with it. Pyrethrins are another common and effective way to get rid of caterpillars. They are generally found in spray form. Look for brands like Take Down and Rotenone-Pyrethrin Spray. Insecticidal soaps are another way to go. These work not only by dissolving the protective layer, or "cuticle," of insects, they also destroy cell membranes causing cell contents to spill out. Look for brands like Safer Insecticidal Soap and Garden Safe.
Many people take a preventative approach and spray their trees with dormant oil in the winter or early fall. This is a thick, plant-based oil that, when sprayed liberally on trees, engulfs and suffocates the insects that are lying dormant in the bark. Look for brands like Eco-Oil and All Seasons Horticultural & Dormant Spray Oil. One last thought: if you don't feel like spraying anything or you are looking for something to use in addition to your spray, use a trunk band. Using duct tape or aluminum foil, construct a band around the trunk of the tree, and coat it with something sticky like petroleum jelly or, better yet, Tree Tanglefoot Pest Barrier.