I’m sure, like me, you (and your garden) are glad we are catching a break from the heat and enjoying the cooler weather, as well as the showers we finally received last week.
I’ve been “out and about” quite a bit lately, looking at pest and disease problems our homeowners face in their lawns and landscapes. Often, we have a situation where people assume that every insect is a pest, and they go ahead and spray without first identifying the critter.
Please remember that there are beneficial insects and other invertebrates in the yard, as well as the ones that can damage plants in our gardens. These beneficial insects include honeybees, lady beetles (a.k.a. ladybugs), butterflies, predators (such as praying mantis) and earthworms.
In addition, there are some that can be either a pest or beneficial, depending on the situation. For example, the caterpillar of the black swallowtail butterfly is also known as the parsleyworm, which feeds on the foliage of carrots, celery, fennel, parsley and parsnips.
If you are a commercial grower of any of these vegetables or herbs and they are causing considerable damage, you could treat the plants with a biological insecticide such as Bt. A powdered form of the bacterium Bacillus thuringiensis , Bt is used to treat for moth and butterfly caterpillars only and does not harm other insects.
Many home gardeners don’t mind the damage, though, and just plant extra for the partsleyworms because they enjoy seeing the butterflies.
One summer, a friend called me to say that parsleyworms had consumed all the fennel in her herb garden. Some of the caterpillars were quite large and some had already pupated. So, I went over there to gather up the remaining skeletonized plants full of smaller caterpillars, to carry them to another garden with plenty of fennel and parsley. I thought to myself as I drove away, “I can’t believe I am driving across town with these worms in my car.” The recipient welcomed me and the “cats” into her garden.
What these two garden club ladies and I realized is that it is worth it to provide host plants for the swallowtail butterflies because they are important pollinators of lots of kinds of ornamental plants. In fact, they are so well loved that people plant flowers just for them and their beautiful kin.
Many butterflies prefer plants that have pink, red, purple, yellow, or orange flowers with either clusters of short tubular flowers or ones with large flat petals to land on.
While sipping the nectar, the butterflies pollinate the plant at the same time, transferring pollen from the anthers (male flower parts) to the style and stigma (female parts) of the same or a different flower.
For more great photos and details on the host plants and flower preferences of Butterflies in the Garden, please see our fact sheet at the Clemson Extension Home and Garden Information Center https://hgic.clemson.edu/factsheet/butterflies-in-the-garden/.