What Damage Looks Like
Spotted Lanternfly leaves a trail of evidence long before you see the insect itself. Here's how to read your yard.
Section 1 of 4
These are the physical traces SLF leaves behind. Any one of them is reason to look more carefully.
What it looks like
Shiny, sticky coating on leaves, branches, outdoor furniture, cars, and pavement under host trees. Looks like someone sprayed sugar water or varnish.
Where to find it
On any surface below a tree where SLF is feeding above. Very noticeable on patio furniture and car hoods under Tree of Heaven.
Action
Look up into the tree canopy immediately. SLF adults and nymphs should be visible.
What it looks like
Black powdery or crusty coating on leaves, branches, and surfaces below. Looks like black dust or mold — because it is mold, growing on the honeydew.
Where to find it
On leaf surfaces, on outdoor furniture, on car surfaces. Often appears 1–2 weeks after honeydew accumulation begins.
Action
The mold itself is not directly harmful to humans but indicates an established SLF population feeding above.
What it looks like
Wet, oozing spots on tree trunks. Sometimes crusty, fermented, or amber-colored. Looks like the tree is "crying."
Where to find it
Most common on maple, black walnut, willow, and cherry. SLF pierces bark to reach phloem tissue — physical damage allows sap to ooze and can introduce pathogens.
Action
Confirms SLF feeding on this specific tree. Check the bark carefully at dusk for aggregating insects.
What it looks like
Individual canes wilting from the tip, then brown patches spreading toward the base. Entire canes may die.
Where to find it
SLF drains photosynthate — energy the plant needs to feed itself. Heavily infested vines cannot store enough energy for winter dormancy, causing cane death.
What it looks like
Unusually large numbers of wasps, yellow jackets, or hornets congregating around a specific tree or area. Often dozens visible at once.
Where to find it
Wasps are attracted to the sugary honeydew that SLF excretes. A tree surrounded by wasps in late summer is often an SLF feeding site.
Action
Don't spray the wasps — find and treat the SLF feeding above them instead.
What it looks like
Gray to dark brown vertical streaks on tree trunks, sometimes with a fermented smell. Can look like fungal disease.
Where to find it
Sap and honeydew running down the trunk oxidizes and discolors bark over time. Confirms historic SLF feeding even after adults are gone.
Section 2 of 4
Quick reference: what damage looks like on the plants SLF feeds on most.
| Plant | Primary Damage Signs | Risk Level |
|---|---|---|
| Grapevines | Cane dieback, honeydew, sooty mold | 🔴 Critical |
| Tree of Heaven | Honeydew, wasp aggregation, sap | 🟠 High |
| Black Walnut | Weeping wounds, honeydew | 🟠 High |
| Willow | Sap oozing, bark staining | 🟡 Moderate |
| Apple trees | Bark wounds, indirect disease pressure | 🟡 Moderate |
| Maple | Sap weeping in summer (unusual) | 🟡 Moderate |
| Ornamental shrubs | Honeydew, sooty mold | 🟡 Moderate |
| Hops | Yield loss, sooty mold on cones | 🔴 Critical |
Section 3 of 4
Common yard problems that look similar but have different causes. Don't misdiagnose.
Brown leaves in summer
Usually drought stress or fungal disease, not SLF.
Holes in leaves
SLF doesn't chew leaves — it pierces and sucks. Holes = caterpillar or beetle, not SLF.
Dead branches
Could be many causes. SLF dieback is at branch tips, not mid-branch.
White powdery coating
Powdery mildew is a fungal disease, not sooty mold from SLF. Sooty mold is BLACK.
Section 4 of 4
You found the signs. Here's your next move.
Look for the insects — check tree trunks, undersides of leaves, especially at dusk.
Report on the map even if you only see damage (not the insect).
Report on the map →Check if the tree is Tree of Heaven — if yes, it's likely your primary source.
ToH ID guide →Consider treatment options.
Control gear guide →Track the infestation over time.
Log kills →Season updates, new guides, and what to do this week. Free. Personalized to your zip code.