Do Spotted Lanternflies Like Black Walnut Trees

Spotted lanternflies do like black walnut trees, and these trees can serve as a food source for them during certain stages of their life cycle.
 
It’s a bit surprising because black walnut trees produce juglone, a chemical that’s toxic to many plants and insects.
 
But the spotted lanternfly has adapted to tolerate it, much like it has with other trees.
 
If you’ve been wondering do spotted lanternflies like black walnut trees, the short answer is yes.
 
They’ll feed on them, though black walnut isn’t their absolute favorite.
 
In this post, we’ll explore why spotted lanternflies are drawn to black walnut trees, what kind of damage they cause, and whether you should be worried if you have these trees in your yard.
 
Let’s get into it.
 

Why Spotted Lanternflies Like Black Walnut Trees

Spotted lanternflies like black walnut trees for several reasons, and it’s mostly about survival and convenience.
 
Here’s why these trees end up on their menu.
 

1. Black Walnut Is a Reliable Host

The spotted lanternfly isn’t super picky when it comes to host trees.
 
It has a long list of preferred plants, including tree of heaven, grapevines, maples, and yes, black walnut trees.
 
Black walnut provides a steady supply of sap, which is what the lanternfly needs to survive.
 
Since black walnut trees are common in many parts of the eastern United States where spotted lanternflies have spread, they’ve become a natural target.
 

2. They Feed on Sap, Not Leaves

Spotted lanternflies don’t chew on leaves like some other pests.
 
Instead, they pierce the bark and feed on the tree’s sap.
 
Black walnut trees have thin enough bark in certain spots for the lanternfly to access the sap easily.
 
This is why you’ll often see them clustered on the trunks of black walnut trees, especially in late summer and fall.
 

3. Late-Season Feeding on Black Walnut

As the weather cools and other food sources dry up, spotted lanternflies will often turn to black walnut trees.
 
In the fall, adult lanternflies need to build up their energy reserves before laying eggs.
 
Black walnut trees, which still have sap flowing, become a convenient stopover.
 
So while black walnut isn’t their first choice, it’s definitely on the list when they’re hungry.
 

4. They Aren’t Harmed by Juglone

Black walnut trees produce juglone, a chemical that’s toxic to many insects and plants.
 
But spotted lanternflies seem to tolerate it just fine.
 
This is part of what makes them such a resilient invasive species.
 
They can feed on trees that would harm or kill other insects, giving them a survival advantage.
 

Do Spotted Lanternflies Damage Black Walnut Trees?

Yes, spotted lanternflies can damage black walnut trees, though the damage is usually not fatal on its own.
 
Here’s what happens when they feed.
 

1. Sap Drainage Weakens the Tree

When spotted lanternflies feed on black walnut trees, they’re draining the tree’s sap.
 
A few bugs won’t make much difference, but in large numbers, they can weaken the tree over time.
 
The tree loses energy it needs for growth, seed production, and fighting off other pests or diseases.
 

2. Honeydew Leads to Sooty Mold

As spotted lanternflies feed, they excrete a sticky substance called honeydew.
 
This honeydew drips onto leaves, branches, and the ground below.
 
It attracts ants, wasps, and other insects, and it also promotes the growth of sooty mold.
 
Sooty mold is a black fungus that blocks sunlight from reaching the leaves, which can slow photosynthesis and further stress the tree.
 

3. Combined Stressors Make It Worse

Black walnut trees that are already stressed by drought, disease, or poor soil are more vulnerable to spotted lanternfly damage.
 
If the tree is healthy and strong, it can usually withstand a moderate infestation.
 
But if it’s already struggling, the added pressure from lanternflies can push it over the edge.
 

How to Protect Black Walnut Trees from Spotted Lanternflies

If you have black walnut trees and you’re dealing with spotted lanternflies, here’s how you can help protect them.
 

1. Scrape Egg Masses in Winter

Spotted lanternflies lay egg masses on tree trunks, rocks, and even outdoor furniture in the fall.
 
In winter, before they hatch, you can scrape these egg masses off and destroy them.
 
This simple step can dramatically reduce the number of lanternflies you deal with in spring and summer.
 

2. Use Sticky Bands Carefully

Sticky bands wrapped around tree trunks can catch lanternflies as they climb up.
 
But you have to be careful because these bands can also trap birds, bees, and other beneficial insects.
 
If you use them, check them daily and cover them with mesh to protect wildlife.
 

3. Remove Tree of Heaven Nearby

Tree of heaven is the spotted lanternfly’s favorite host.
 
If you have tree of heaven growing near your black walnut trees, removing it can reduce lanternfly activity in the area.
 
Just be sure to remove it properly, as tree of heaven can regrow from roots and seeds.
 

4. Encourage Natural Predators

Birds, spiders, and praying mantises will eat spotted lanternflies.
 
Creating a garden that supports these predators can help keep lanternfly numbers in check naturally.
 
Avoid using broad-spectrum pesticides that kill beneficial insects along with the pests.
 

So, Do Spotted Lanternflies Like Black Walnut Trees?

Spotted lanternflies do like black walnut trees, and they’ll feed on them when other food sources are scarce.
 
While black walnut isn’t their top choice, it’s still a host they’ll use, especially in late summer and fall.
 
The damage they cause is usually not fatal, but combined with other stressors, it can weaken the tree over time.
 
If you have black walnut trees, keep an eye out for spotted lanternflies and take steps to manage them before they become a bigger problem.
 
Hope this post has helped you understand why spotted lanternflies like black walnut trees and what you can do about it.