Protect Your Trees from Spotted Lanternflies: What You Need to Know

Spotted lanternflies (SLF) are here to stay for the foreseeable future, and while they may not cause catastrophic damage to most trees, they can create a sticky, frustrating mess when they swarm. Knowing how to manage them — and which trees are most at risk — is key to keeping your landscape healthy and enjoyable.

What Are Spotted Lanternflies?

Spotted lanternflies are sap-sucking insects with striking black spots and bright red underwings. Like other insects that feed on sap, they excrete a sugary liquid called honeydew, which can coat leaves, patios, and furniture. Honeydew attracts black sooty mold, which grows on the sugars, adding to the mess.

The good news? Despite the hype, they cause only minor direct damage to most trees. The biggest problems occur when dozens swarm a tree, weakening it over time and creating unsightly honeydew and mold.

Their Favorite Hosts

Spotted lanternflies are particularly attracted to:

  • Tree of Heaven (Ailanthus altissima) – an invasive species that destroys biodiversity and their favorite host.
  • Red maples
  • Willows
  • Crape myrtles
  • River birches
  • Grape vines

If you have a Tree of Heaven on your property, the best step you can take is to remove it. This invasive tree outcompetes native plants and fuels SLF infestations — nearly every bad outbreak we’ve seen has been tied to its presence. Removing it protects both your trees and the larger ecosystem.

How to Manage Spotted Lanternflies

1. Monitor Regularly
Walk your property and check your trees — especially the species listed above. If you notice a dozen or more SLFs on a single tree, it’s time to act.

2. Destroy Egg Masses
From September through early spring, look for their mud-like egg masses on trees, rocks, or even outdoor furniture. Scraping and destroying them can significantly reduce future populations.

3. Use Professional Traps
If your landscape aesthetic allows, consider professional traps such as Penn State’s Circle Trap or similar models. Unlike sticky tape, these traps are designed to capture SLFs without harming beneficial insects.

4. Treatments and Injections
Our Quarterly and Monthly Plant Care Programs include SLF treatments. For smaller trees, systemic sprays are often effective. But if your tree is too large for thorough coverage, trunk injections may be necessary. These should be repeated annually if swarming continues, especially on vulnerable species like red maples. Injections typically cost $200–$350 per tree, depending on size.

5. Focus on the Ecosystem
The most important step is removing Tree of Heaven from the community. Beyond being the SLF’s top host, it is the most invasive tree in our area, choking out biodiversity — which is the foundation of a healthy, resilient ecosystem.

Looking Ahead

Spotted lanternflies will remain part of our landscape for years. Populations may rise before they fall, and we may eventually see native predators adapt to feed on them, helping keep their numbers in check. In the meantime, proactive management and a focus on biodiversity will keep your trees healthier and your property more enjoyable.

Ready to Take Action?

Our arborists are here to help — from scouting your property and removing invasive hosts to applying treatments or trunk injections where needed. Contact us today to learn more about our Plant Care Programs or to schedule a consultation. Together, we can reduce spotted lanternfly populations and strengthen the ecosystems that keep our landscapes thriving.

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