Good Bug, Bad Bug
Written by: Charlotte Glen, Horticulture Agent
There are all kinds of insects in this world. Some of them eat plants, others feed on nectar, a few feed on blood, and then there are the bugs that eat each other. Officially known as beneficial insects, these good bugs help keep plant damaging insects under control naturally. They are definitely something you want in your garden. Luckily, creating a yard that beneficial insects will want to call home is simple and inexpensive.
Meet the Good Guys
There are dozens of different beneficial insects roaming the yards and gardens of eastern North Carolina. Some are predators who hunt down bad bugs and devour them on the spot. This group includes insects like the well known ladybug, bee look-alikes known as syrphid flies, delicate appearing lacewings, the aptly named assassin bug, and even wasps. Some of these good insects feed most voraciously on pests when they are young and less easily recognized so it is important to be familiar with what these good guys look like as juveniles as well as adults to avoid accidentally killing them. While not insects, other good guys you will find in your garden that help with pest control include spiders, lizards, frogs, toads, and birds. Many of the things you do to attract beneficial insects will also attract these garden helpers.
Another group of beneficial insects have a more stealthy way of attacking bad bugs. They lay their eggs inside the bad guys and devour them from within. These are the parasites. Many of them are extremely small and rarely seen, though you may run across their handiwork. One the most frequently encountered is the tiny, non-stinging braconid wasp, whose white, cigar shaped cocoons are sometimes found attached to caterpillars. If you find a caterpillar covered with these cocoons, leave it in place to allow the wasps to hatch and seek new prey.
One of the most important things you can do to attract beneficial insects to your yard is to grow a variety of different plants, including trees and shrubs, and especially flowers. Many beneficial insects feed on nectar and pollen in addition to bad insects, so include several types of flowers in your yard and try to have something in bloom from spring through fall. Plants that have many small flowers clustered together or daisy type blossoms are especially attractive to beneficials. These include annuals like marigolds, cosmos, sunflowers, gomphrena, and zinnias, all which are easy to grow from seed and can be planted now.
The flowers of many herbs make great beneficial bait. If you have basil, parsley, cilantro, or dill growing in your garden allow them to go to flower to lure beneficials to your yard. The blossoms of perennial herbs are also highly attractive to beneficials. These include chives, thyme, oregano, and especially fennel. Perennials that beneficials find irresistible include purple coneflower, sedum, yarrow, joe pye weed, goldenrod, asters, butterflyweed, ironweed, agastache, rudbeckia, and coreopsis. Plant groups of these flowers in your landscape and vegetable garden to lure beneficials into your yard.
Pesticides and Beneficials
Beneficial insects are easily killed by insecticides and usually take longer to recover from being sprayed than pest insects. Avoid spraying pests when they first appear to give beneficials time to move in and do their job. When you do need to spray use an organic product like neem, spinosad, B.t., horticultural oil, or insecticidal soap since these products break down quickly and are less damaging to beneficials. Keep in mind that in order to maintain a healthy population of beneficial insects there will always need to be a low level of pest species present for them to feed upon and that controlling pests naturally aims to maintain a balance of good and bad species, rather than eradication of pests.
Learn more about cultivating a beneficial friendly yard and other methods of natural pest control at a free class taught by Pender Horticulture Agent, Charlotte Glen, Thursday, May 26, 10 a.m. to noon, at the Surf City Community Center. Registration required. To sign up or find out more, call Pender Cooperative Extension at 910-259-1235.
Learn about and see images of many types of beneficial insects from these great links:
- Florida Cooperative Extension has a series of beneficial ID sheets:
- NCSU Biological Control Information Center – learn more about using beneficials to control pests naturally: http://cipm.ncsu.edu/ent/biocontrol/goodbugs/pirate.htm
If you have questions about controlling pests, growing vegetables, or caring for your yard, contact your local Cooperative Extension office. In Pender County call 259-1235, visit our office at 801 S. Walker Street in Burgaw (office hours: Mon – Fri, 8 a.m. – 5 p.m.), or post your questions online using our ‘Ask an Expert’ widget available at http://pender.ces.ncsu.edu. Visit the Pender Gardener Blog to stay up to date on the latest gardening news, http://pendergardener.blogspot.com/.