There are a few reasons that these slow-moving little guys cause people angst. First of all, they're weird looking. They are oddly colored, some have spines, and, by golly, they're eating our plants. People have used the chemical equivalent of flame-throwers for much less. Your panic, and choice of an unnecessary treatment, can easily cause your plant more harm than the caterpillars.
Look at these common caterpillar situations:
Barb goes out on her deck one afternoon. Her oleanders are blooming like heat-tolerant troopers. Wait, though! What's that?
Chances are you've seen these babies, and you were just dying to spray or dust something on them. (One customer even told us she sprayed Raid on them. No! No! No!. Raid is not designed for plant use. It will fry your plants.)
Solution: Keep drinking whatever cold beverage you were enjoying, and do nothing. These caterpillars are doing no more damage to your oleanders than if you cut them yourself. As we know, oleanders respond very well to pruning and respond with lush new growth.
Nancy heads out to her herb garden to cut some parsley for her chicken surprise. The surprise is that there's no parsley! The striped charmer to the left, and his cronies, have nibbled it down to the stems. Maybe you've got a second parsley and they're nibbling that one too.
Swallowtail caterpillars love herb gardens because herbs are their primary food source. Dill, Cilantro, Fennel, Parsley, and even Rue can woo these guys.
Solution: Follow Paul McCartney's advice and "let it be". In a few weeks they will go off and become beautiful butterflies. We've also found that birds, lizards, and even wasps will gladly take them off your hands. Wasps are VERY good for the garden. If you don't swat at them as they hunt for dinner, they aren't a threat. (If you're allergic-obviously don't place this plant right where you relax.) Herbs respond like they've been pruned. They will grow back, so continue to water regularly. You can even use fish emulsion or blood meal on them to give them an extra boost.
If you thought it was raining cats and dogs, or even men for that matter, you would be mistaken. It's tent caterpillars.Now you really want to do something, right? They love my pecan tree. Some people have suggested applying a systemic insecticide drench to trees with tent caterpillars. I understand, but let me tell you why that's not smart.
- Tent caterpillars are only caterpillars for a very short period of time. By the time the systemic insecticide goes all the way up the tree, the caterpillars will be long gone!
- Do you really want to put systemic insecticide into a plant that you might eat? No. Even if the chemical is out of the tree by the time the pecans form-how will you be sure?
- The tree does not suffer at all. It grows back like they were never there.
This is the caterpillar of the Giant Swallowtail butterfly. It likes citrus trees, and its ugly face shouldn't cause you panic. We all remember the story of the Ugly Ducking who became a swan, right?
So, to my left is the poor duck and to my right is the swan!
Solution:Use this caterpillar to teach your kids not to judge a book by its cover. Your plants will be fine. If you have a large number of these on a tiny citrus, just pluck them off. Okay, tell someone who doesn't get the willies to pluck them off. Doesn't your neighbor have a HUGE citrus tree that could use a trim?
By now you're just fed up. You want to do SOMETHING! If, by chance your tomato or pepper plants are disappearing before your eyes, chances are a Tomato Hornworm has found them. What? Something endanger your tomato plant? I know, it's crazy, but it happens.
Solution: Bacillus Thuringiensis, also known as BT, is the active ingredient in a product called Dipel Dust. This is the best insecticide for caterpillars. It is inexpensive, and it's only really necessary in the case of the Tomato Hornworm or, possibly, the Cabbage Looper. If you have another situation where some caterpillars need killin', it works on all kinds of caterpillars. We recommend identifying them before resorting to this. Often, as mentioned above, the caterpillar will do no harm.