By now, many of us have gotten used to the heat and humidity—or at least have become accustomed to it. However, when it comes to insect pests, few gardeners ever get used to them. Well, friends, the months of August and September are the heyday for insects. Over the course of the summer their numbers have rapidly increased, so expect to see a multitude of six-legged critters out there.
When you have an insect-encounter, avoid the credo of some gardeners that “the only good bug is a dead bug.” Not all insects are harmful. In fact, beneficial insects handily outnumber harmful pests. Beneficial insects are the natural enemies of harmful or damaging insects and can be divided into two main categories: predators and parasites.
Predators hunt and feed on other insects. They include praying mantids (the Carolina mantid is the official state insect of South Carolina), lady beetles, lacewings, and assassin bugs.
Parasites hatch from eggs inside or on another insect and they eat their host insect as they grow. Perhaps you’ve seen the white cocoons adorning the body of a tomato hornworm. Inside the cocoons are braconid wasp larvae that fed on the innards of the caterpillar and now are a step away from changing into adult wasps.
Releasing beneficial insects into your landscape or garden may help, but it’s better to conserve the beneficial insects already there by managing harmful pests with knowledge and good sense. Here’s how:
1.Watch for and learn to identify pests. At least once a week walk through your landscape and examine your plants for pests. Learn to distinguish between the harmful and helpful insects in your garden and landscape. Check out the colorful fact sheet titled “Beneficial Insects” at the Clemson University Department of Entomology web site at http://entweb.clemson.edu/cuentres/eiis/bbam/bbam.htm. If you spot an insect and are unable to identify it, take a sample to your Clemson Extension office.
2. When trouble strikes, turn to nonchemical controls first. Insects such as aphids and spider mites can be hosed off with a strong spray of water, others such as Japanese beetles and orangestriped oakworm caterpillars can be handpicked.
3. Sometimes it is necessary to resort to more potent but least toxic measures such as insecticidal soap or the botanical insecticide neem to control soft-bodied insects, such as aphids and mites.
4. Occasionally you may have to turn to more potent pesticides, especially when you feel the damage is more than you or your plants can tolerate. Consider spot-treating heavily infested plants instead of making a blanket application that can destroy beneficial insects. Use recommended pesticides and apply according to label directions. Foraging honeybees and other pollinators are sensitive to these insecticides, so treat the plants in early morning or late evening when no bees are present.
To attract and maintain beneficial insects in your garden, grow a variety of flowering plants that bloom from early spring through fall. While the larvae generally feed on insects and mites, adults feed on nectar and pollen—either exclusively or to supplement their diet when insects or mites are in short supply. So feel free to add more color and beauty to your garden with yarrows, daisies, and sedums. As I tell my wife who occasionally questions my purchases, I’m doing it for the beneficial insects—a gardener’s best friends.