Photo courtesy of ISU Extension and Outreach.

Japanese beetles can be a common pest for homeowners, but the outdoors is where these bugs cause the most problems.

Washington County Extension Director Nancy Adrian explains, “They like to feed on foliage and flowers and fruit and actually more than 300 different plants. So they have a voracious appetite and they’re not real picky on what to eat they like a lot of different things. Linden trees appear to be one of their favorites.”

Washington County is one of several in the state that is home to Japanese beetles, which typically emerge from mid-June and stick around for 6-8 weeks. Adrian says that defoliage of well-established linden trees is usually not fatal, but can be more dangerous for newly planted ones, or those in poor health. ISU Extension says that Japanese beetles can’t be effectively controlled by traps and that traps can actually attract a larger population of beetles. Small, recently planted trees can be sprayed by carbaryl or permethrin to deter the pests. Adrian adds, these chemicals must be sprayed repeatedly to protect trees. The lifespan of a Japanese beetle is 30-45 days, and most of them are gone by late August.