Telling the Difference Between Good Bugs & Bad Bugs

A Q&A with arborist/entomologist Laurie Reid Dukes

Laurie Reid Dukes is Charlotte’s assistant city arborist, ensuring our urban streets stay picture-worthy with cankerworm-free willow oaks. Her knowledge of insects is impressive. She’s an entomologist—she has both bachelor’s and master’s degrees in entomology from Clemson University—and she’s been working in forest health since 2004. Dukes studies insects, their environments, and their relationships with humans.


Charlotte Home + Garden:  Let’s talk about one of summertime’s biggest downfalls: pests. Can we use any ol’ bug spray to solve the problem?

LD: There are many insecticide sprays on the market and, unfortunately, many of them are broad-spectrum insecticides, which kill all insects—both the beneficial and pest insects. The most common insecticides that can be found on the grocery store or big box store shelves are the broad-spectrum insecticides.


Wheel bug

CHG: So there are good bugs and bad bugs. Which bugs are the good guys?

LD: There are many beneficial insects, far too many to name, but a few common ones people may see in a backyard garden are: wheel bug, green lacewings, brown lacewings, ladybugs, fiery searcher beetles, hoverflies, flower flies, syrphid flies, parasitoids, and spiders.


CHG: What do some of these beneficial insects do?

LD: Fiery searcher beetles eat cankerworms, and parasitoids are flies and wasps which develop inside the hosts, killing the hosts.


CHG: We all know how much Charlotteans love (read: hate) their cankerworms. How do we keep the good bugs alive while killing the bad ones?

LD: When dealing with an insect pest, I prefer to use an integrated pest management approach, where having knowledge of the pest and its habits is important. Often, managing the environment can reduce the pest to a manageable level and the use of pesticides is not necessary.


Top: Ladybug
Bottom: Fiery searcher beetle

CHG: What are some examples of integrated pest management?

LD: An example of changing the habitat is: If ticks are an issue in a yard, to keep the vegetation mowed and reduce leaf litter, brush, and tall weeds from around the home. Additionally, do not plant vegetation that attracts deer or other wildlife that may carry ticks. Or, use fencing to exclude those animals from a yard. If a pest is entering a structure, exclusion includes properly sealing cracks around doors, windows, or pipes that may allow the pest to enter a structure, and covering attic vents with fine mesh metal. Also, removing containers which hold water will reduce an Asian tiger mosquito population, as they lay eggs in standing water.


CHG: If a homeowner does decide to go the bug spray route, what do you recommend?

LD: If an insecticide is required, it is best to choose one that is targeted to that pest; many insecticides are targeted to specific groups of insects. The best advice for determining which insecticide treatment to use is to have knowledge of which insect is a pest. Once the insect is identified, it is important to research the life history of the insect to determine which life stage will be impacted by an insecticide. Some insects are damaging or a nuisance during the larval stage, the adult stage, or both larval and adult stages of their lives. After that knowledge is obtained, it’s important to know the best method for delivering the insecticide, where the insecticide should be sprayed, and what time of year the insecticide should be sprayed to have the most impact on the insect.

Categories: Expert Advice (People)