Knowledgebase
Japanese beetles #907565
Asked June 27, 2025, 8:48 PM EDT
Weld County Colorado
Expert Response
Hello I have attached a Japanese Beetle info sheet from CSU. Here is a summary regarding the beetle and treatment options. Note the article goes into more detail:
Quick Facts
• Japanese beetle adults chew
flower blossoms and leaves
of many commonly grown
plants.
• Japanese beetle larvae are a
type of white grub that feeds
on the roots of grasses.
• Adults are best controlled
by handpicking or by use of
certain insecticide sprays.
• Japanese beetle traps can
capture many adults have
never been shown to reduce
damage to nearby plants.
• Japanese beetle larvae can
be controlled with certain
insecticides or by insect
parasitic nematodes.
Please NOTE:
There have been national or statewide changes that have restricted certain pesticides for homeowners. Remember that "pesticide" is the word to describe products that are used to control (kill) something - herbicide, insecticide, miticide, fungicide, etc.
The first is the herbicide glyphosate (the active ingredient in Roundup, KleenUp). Bayer, the owner of RoundUp products, removed glyphosate from homeowner formulations starting in 2023. Glyphosate is still available in agricultural formulations, but not in the lawn and garden section. The current active ingredients in homeowner RoundUp formulations are triclopyr and fluazifop. Fluazifop is sold as "grass-be-gone" - but triclopyr is sold as "tough brush killer" or "poison ivy killer" and is a root active product. There is a legitimate concern with people using this product to control weeds or grass in landscapes where there are actively growing tree roots.
The second is that imidacloprid, is a common insecticide used to control various insects, is only available for purchase through licensed pesticide dealers. This, for the most part, does not include any box stores or Amazon. It does include some farm and ranch supplies and garden centers. This was state legislation passed to support pollinator health. If people were purchasing "Bayer Tree and Shrub Insect Control" (or similar products) for emerald ash borer, they would have to purchase it through a licensed pesticide dealer. (See the list here)
Best,