Spotted Lanternfly vs Japanese Beetle: How to Tell the Difference
Compare two major invasive insects in the eastern United States: the spotted lanternfly and the Japanese beetle, both of which damage a wide range of plants.
At a Glance
Spotted Lanternfly
MODERATE- Type
- Insect
- Severity
- MODERATE
- Affected States
- 21 total (21 active)
Symptoms
Masses of gray egg cases on tree trunks and hard surfaces, weeping sap wounds on trunks, black sooty mold on bark and surrounding surfaces, swarms of adults with distinctive spotted wings
Japanese Beetle
MODERATE- Type
- Insect
- Severity
- MODERATE
- Affected States
- 35 total (35 active)
Symptoms
Skeletonized leaves with only veins remaining, metallic green and copper beetles feeding in groups, brown patches in lawn from grub damage, defoliation progressing from top of canopy downward
Similarities
What makes Spotted Lanternfly and Japanese Beetle easy to confuse:
- Both are invasive insects originally from Asia
- Both feed on a wide range of host plants including grapes, fruit trees, and ornamentals
- Both are targets of state and federal quarantine and management programs
- Both can congregate in large numbers, causing alarm for homeowners
- Both adults are active during the summer months
Key Differences
| Feature | Spotted Lanternfly | Japanese Beetle |
|---|---|---|
| Type | Planthopper (sap-feeding insect) | Scarab beetle (leaf-chewing insect) |
| Appearance | Gray wings with black spots (at rest); bright red hind wings when flying | Metallic green and copper-colored, oval-shaped, about 1/2 inch |
| Feeding method | Pierces bark and stems to feed on sap; excretes honeydew | Chews leaf tissue between veins, "skeletonizing" leaves |
| Key host | Tree of heaven (*Ailanthus*) is preferred; also grapes, hardwoods | Over 300 plant species; roses, grapes, lindens, and Japanese maples are favorites |
| Damage signs | Sticky honeydew coating, sooty mold growth on surfaces below feeding sites | Lacy, skeletonized leaves with only veins remaining |
| Life stage damage | Nymphs and adults both feed on plants | Adults skeletonize leaves; grubs damage lawns and turf roots |
How to Tell Them Apart
- Look at the feeding damage: Spotted lanternfly damage appears as weeping sap from bark, sticky honeydew residue, and black sooty mold on surfaces beneath the tree. Japanese beetle damage shows up as skeletonized leaves with only the veins remaining.
- Identify the insect: Spotted lanternfly adults are about 1 inch long with distinctive spotted gray forewings and red-and-black hind wings. Japanese beetles are smaller, oval, and metallic green with copper wing covers.
- Check for honeydew: A sticky, shiny coating on leaves, branches, or surfaces below the tree indicates spotted lanternfly. Japanese beetles leave no sticky residue.
- Look at the ground: Spotted lanternfly nymphs (black with white spots, later red with white spots) hop and crawl on tree trunks. Japanese beetle grubs are C-shaped white larvae found in soil under turf.
- Note plant preferences: Spotted lanternflies are often found on tree of heaven, walnut, and grapevines. Japanese beetles favor roses, lindens, grape leaves, and ornamental plants.
Frequently Asked Questions
Which pest causes more economic damage?
Both cause significant economic damage, but to different sectors. Spotted lanternfly is a major threat to the grape and wine industry, hardwood lumber, and orchard crops. Japanese beetles damage turf, ornamental plants, and fruit crops. Together, they cost billions annually.
Can I use the same treatment for both?
Some broad-spectrum insecticides are effective against both, but targeted approaches differ. Japanese beetles can be managed with traps (though effectiveness is debated), milky spore for grubs, and neem oil. Spotted lanternfly management focuses on tree banding, systemic treatments, and removal of tree of heaven host plants.
Are spotted lanternflies harmful to humans?
No. Spotted lanternflies do not bite, sting, or pose any direct health risk to humans or pets. They are strictly plant feeders.
Should I stomp on spotted lanternflies?
In quarantine zones, authorities encourage killing spotted lanternflies on sight. Stomping is one simple method. However, broad-scale population management requires more comprehensive approaches including tree banding, insecticide applications, and host tree removal.
Do Japanese beetle traps work?
Japanese beetle traps can actually attract more beetles to your yard than they catch, potentially increasing plant damage. They are best used for monitoring rather than control. Hand-picking beetles into soapy water in the morning when they are sluggish is often more effective for garden-scale management.