06/16/2026
Japanese beetles will begin emerging soon, so here are your annual management reminders:
-Because Japanese beetle defoliation will not kill otherwise healthy, established plants, you could just tolerate the damage, even though it looks pretty bad.
-Traps are not an effective way to control Japanese beetles. They actually attract more beetles to your yard than would otherwise occur.
-Handpicking is only somewhat practical for small gardens or plants. It's a daily task that's best done in the morning when beetles are sluggish.
-If using residual insecticide sprays, you must be thorough and frequent. It will take 3-5 sprays over the 6 weeks of beetle presence, and more if it rains. Always read and follow label directions.
Learn more in this Japanese beetle article: https://go.iastate.edu/1E1KLL
ISU Extension and Outreach - Agriculture and Natural Resources