We’ve been helping folks around Raleigh deal with caterpillar infestations for years, and two of the most commonly confused pests we hear about are the Eastern Tent Caterpillar and the Fall Webworm. While both can spin noticeable webs in your trees, they differ in several ways that affect the control strategy you choose. In this article, we’ll take a friendly deep dive into what makes them unique, why they appear in your yard, and how you can effectively manage or eliminate them.
Recognizing the Culprits: A Quick Breakdown
First, let’s talk appearances. Eastern Tent Caterpillars typically show up in early spring, spinning their webs in the crooks of tree branches. They’re slender, blackish caterpillars with a white stripe running down their back and a series of oval-shaped blue dots along their sides. Fall Webworms, on the other hand, are fuzzy caterpillars that create large, loose webbing toward the tips of branches during late summer and fall. Their caterpillars can be pale yellow or green with black spots.
Beyond visuals, timing is a key difference. Eastern Tent Caterpillars appear mainly from March to early May in the Raleigh area. Fall Webworms make their appearance a bit later—usually from July through September. It’s also worth noting that the Eastern Tent Caterpillar typically prefers wild cherry, apple, and crabapple trees, whereas Fall Webworms aren’t as picky and will attack over 100 different species of trees, including hickory, walnut, and pecan.
Why These Pests Love Raleigh
Raleigh has a mild climate with warm, humid summers and relatively moderate winters, making it the perfect habitat for many insects. Our large variety of hardwood trees and ornamental plantings provides plenty of food and shelter for these caterpillars. According to the NC State Extension, Raleigh homeowners can see between one to three generations of Fall Webworms each year, depending on weather conditions. Eastern Tent Caterpillars, however, typically produce just one generation per year.
Damage Concerns: How Much Harm Do They Cause?
It’s important to keep perspective. While both of these pests can create eyesores, they rarely kill mature trees. Eastern Tent Caterpillars can defoliate branches, leading to reduced vigor and sometimes stunted growth. Younger saplings or stressed trees may suffer more. Fall Webworms can cause extensive leaf damage by feeding inside their webs, but healthy trees generally bounce back the following season. However, if an infestation gets out of control or recurs every year, the repeated defoliation can weaken trees and make them more susceptible to other pests or diseases.
Biology Basics: Life Cycles and Habits
Eastern Tent Caterpillar:
- Egg masses overwinter on small twigs.
- Eggs hatch in early spring as leaves begin to bud.
- The caterpillars feed in colonies for about six weeks.
- They form cocoons and emerge as moths in early summer.
Fall Webworm:
- Adult moths appear in late spring or early summer.
- Females lay egg masses on the underside of leaves.
- After hatching, caterpillars create silken webs where they feed.
- Multiple generations can occur until fall, when they pupate in soil or leaf litter.
Effective Control Strategies
At Wake Pest, we usually start by advising property owners on the least disruptive methods first. Pruning out webs and caterpillar clusters is an excellent, immediate step. Clip off infested branches—if it’s feasible—and bag up the nests to remove them from the tree environment. Manual removal works best for small or easily accessible infestations.
For more serious infestations, biological controls come in handy. For instance, Bacillus thuringiensis (Bt) is a natural bacterium that targets caterpillars. When sprayed on the leaves, it’s consumed by feeding caterpillars and disrupts their digestive system. Bt is generally safe for beneficial insects, pets, and people, making it a popular choice for eco-friendly control.
Comparing Chemical Solutions
Sometimes, larger or persistent infestations need chemical intervention. We often recommend insecticidal soaps or horticultural oils for limited infestations. These products help penetrate webbing and suffocate the caterpillars. More potent synthetic insecticides might be reserved for severe outbreaks. If you go that route, be mindful of pollinators in your yard. Spraying in the evening when bees are less active can help reduce impacts on other species. According to the U.S. Environmental Protection Agency, overuse of chemical insecticides can lead to resistance issues, so it’s crucial to apply them responsibly.
Protecting Raleigh’s Ecosystem
We love living and working here in Raleigh because of its green spaces, tall oaks, and vibrant local flora. Taking an integrated approach that combines mechanical removal, biological controls, and responsible use of chemicals helps preserve beneficial insects, birds, and other wildlife. Birds, for instance, are natural predators to both Eastern Tent Caterpillars and Fall Webworms—especially species like robins and blue jays. If you can tolerate a few webs without any major damage, sometimes letting nature take its course is the best strategy.
When to Call a Professional
If you’ve pruned, sprayed with Bt, and still see extensive webs each year, it may be time to bring in professionals like us at Wake Pest. We can assess your particular situation, identify the pest correctly, and tailor a management plan that fits your needs. Sometimes, an aerial application or a more targeted insecticide approach can handle large infestations that are beyond DIY measures. Or you might need advice on pruning, tree maintenance, or even planting new species that are less appealing to these pests.
Wrapping It Up
Eastern Tent Caterpillars and Fall Webworms are two of the most common web-spinning caterpillars in Raleigh. Although they can look similar at first glance, each has a unique appearance, life cycle, and preferred host trees. By staying vigilant—especially in early spring and late summer—you can catch infestations early and stop them before they spread.
For more personalized guidance, don’t hesitate to reach out to us at Wake Pest. We’re always happy to chat about effective, eco-friendly ways to keep your trees healthy and web-free all year long.