Of all the visitors our gardens see every year, caterpillars can be the most problematic. The larva phase for butterflies and moths, caterpillars can be cute or creepy, helpful or harmful depending on the species and where they land. Here at Gardzen, we believe that gardens should work with rather than against nature and we’re in favor of creating insect-friendly spaces and gardens that support pollinators of all types. We also firmly believe that gardening education can help solve many problems we have with yards, gardens, and the critters that inhabit them. So with that said let’s dig in and learn a bit more about caterpillars and what they do in our gardens.
The first and most important thing to remember when we find caterpillars in your garden is this: caterpillars come from a wide variety of insect species and most of them are helpful to our garden spaces. So before we start panicking, let’s take a moment to identify the caterpillars in question and learn a bit about what effect if any they’ll have on our plants. The good news is that there are plenty of resources including some online tools to help us figure out which kind of caterpillars we have. More than likely you’ll find that the caterpillars living on your plants are harmless as they are and will become something beautiful when they mature into butterflies or moths. Both butterflies and moths are pollinators, so they’ll help many of our plants thrive. Some caterpillars may belong to endangered or threatened species like Monarch butterflies, and deserve extra care. The take-home from this is most caterpillars are good to have and we should leave them alone if not help them grow.
As with all guidelines, however, there are exceptions. Some caterpillars are voracious feeders and can strip our plants quickly. Cabbage moths, tomato hornworms, and tentworms (neither of which are worms; they’re both actually caterpillars) are some of the most infamous for this. Fortunately, if you see them on your plants—or any other problem caterpillars—you do have some options for dealing with them:
· As with all things gardening, prevention is better than cure. It’s best to ensure that offending insects and other pests don’t take up residence; removing them after they’ve moved in can be very difficult. There are a few ways to do this: companion planting can help by inserting plants that repel unwanted insects among your veggies and flowers. There are some organic preventative sprays and treatments that will likewise repel pests or prevent them from breeding on your plants. We always recommend an organic or natural approach when possible; gardens are part of nature as we mentioned previously.
· If you have a particularly nasty or large infestation, manual removal is a quick and effective option. Don a pair of gloves, pick the unwanted bugs off your plants, and either squish them or drop them into a bucket of soapy water. It’s that simple, and it can be a fairly speedy solution. It also gives you a chance to look over your plants and assess the damage to determine how you should help them recover. We recommend avoiding dumping the bug-filled water on your compost heap or down a storm drain; flush it down a toilet or dispose of the bugs in the trash instead.
· If the infestation is really bad or you’re for whatever reason unable to do a manual removal, there are some organic pesticides that can help control unwanted caterpillars. These tend to be widely available these days, so you should be able to find them at your local garden supply store. B.t./ Bacillus thuringiensis is a bacteria often used as an organic pesticide and is especially effective for pest caterpillars. Neem oil is another organic, derived from the neem plant, and is generally diluted in water and applied as a spray. It’s effective for tomato hornworms, cabbage moths/cabbage worms, and aphids.
Again, most caterpillars are benign or beneficial and we should support them. Insects add life to a garden and may help with pollination. Unwanted caterpillars can generally be dealt with without artificial pesticides or other harmful products. We hope this blog helps you understand what caterpillars are, the role caterpillars play in our gardens, and what you can do about pest caterpillars if you should find them. If you have questions or advice to share, please let us know. Gardzen is all about community and we love to hear from you!
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