94% confidence
Based on 20,000+ analyzed cases
Japanese Beetles on rose
What's Happening
Popillia japonica adults emerge in mid-summer, aggregating on roses (their favorite food) to mate and feed. They chew large irregular holes in flowers and skeletonize leaves. They emit pheromones that attract more beetles.
How to Fix It
- 1
Hand-pick beetles in the early morning when they are sluggish and drop them into a bucket of soapy water
- 2
Do NOT use pheromone traps near your roses, as they attract more beetles from miles away than they catch
- 3
Cover prized blooms with fine mesh netting
- 4
Apply neem oil or spinosad as a deterrent (though efficacy is limited during heavy swarms)
How to Prevent It
Treat the lawn in late summer/early fall with milky spore or beneficial nematodes to kill the grubs before they mature into next year's adults.
Related Problems
Frequently Asked Questions
What causes japanese beetles on my plant?
Popillia japonica adults emerge in mid-summer, aggregating on roses (their favorite food) to mate and feed. They chew large irregular holes in flowers and skeletonize leaves. They emit pheromones that...
How do I fix japanese beetles?
Hand-pick beetles in the early morning when they are sluggish and drop them into a bucket of soapy water. Do NOT use pheromone traps near your roses, as they attract more beetles from miles away than they catch.
How do I prevent japanese beetles from happening again?
Treat the lawn in late summer/early fall with milky spore or beneficial nematodes to kill the grubs before they mature into next year's adults.