How to Battle Japanese Beetles in your Landscape
August 7 , 2025 . Jill Livingston
My dad, an entomologist, taught me at an early age not to fear insects, but to appreciate their importance in nature. So, the first time I saw a Japanese Beetle in my Colorado garden, I left it alone and literally admired how stunning it was – metallic green body with a hard, iridescent shell that seemed to glisten in the sunlight. Sounds beautiful right? Ignorance is truly bliss until you see how quickly they reproduce, leaving a trail of garden carnage. Fast forward to the present – now I know that combatting Japanese Beetles could literally be a full-time job! Unfortunately, they’re likely here to stay. The best thing we can do is Know the Facts and Methods for minimizing their damage to our landscape, while keeping our sanity.
Identify Japanese Beetles and Know their Life Cycle
Getting rid of Japanese beetles gets a lot easier when you know WHAT to look for and WHEN to act. Spotting them early, recognizing their favorite host plants in your landscape, and knowing what controls do and do not work can make all the difference.
Adult Beetles:
Roughly ½” long—think the length of a pencil eraser.
Metallic green body with bronze/brown wings
White tufts of hair along each side of the abdomen
Hard, shiny shell
Larvae (Grubs):
Creamy white with a brown head
C-shaped body, usually about 1” long when mature.
Found curled up in the soil, especially when digging up
turfgrass.
Note that grubs in the lawn look like other beetle larvae but turn up in larger numbers that take a toll on turfgrass roots.
2. What Japanese Beetles DO to Your Landscape
In both their larval and adult stages, Japanese beetles can damage your landscape.
As larvae, they prefer irrigated turfgrass to overwinter, feeding on grass roots. This root damage inhibits the lawn’s ability to take up water, making it more susceptible to drought stress.
As larvae population increases, patches of grub-infested grass can die. Although they prefer irrigated lawns, the larvae can live in any soil with plant roots if they receive enough water.
Adults emerge from the soil in late June through August, eating leaves, buds, and flowers. Adults “skeletonize” leaves, eating the soft leaf tissue between leaf veins
3. Options to Control or Reduce Damage from Japanese Beetles
Here are a few things you can try.
The number one thing you can do is PREVENT Japanese Beetles from visiting your yard in the first place. The best way to do this is Avoid Using their Favorite Host Plants! Some of their favorite plant snacks include:
Roses
Rose-of-Sharon/Hibiscus
Virginia Creeper
Raspberry
Grape
Hollyhock
Apple and/or Crabapple
American Linden
American Mountain Ash
American Elm
Eliminate as much traditional turfgrass lawn as possible.
DO plant hardy shrubs, trees, and perennials which are not known Japanese Beetle magnets.
DO remove Japanese Beetles by hand. They are most sluggish in the morning and can easily be removed from plants and drowned in a container of water. Important – don’t forget to use a container with a lid!
Whatever you do, DO NOT use a Japanese Beetle Trap!!
Traps attract larger numbers of beetles to your yard, maybe even from your neighbor’s yard, using female beetle or floral scents.
According to the Colorado State University Extension, it’s never been proven the traps reduce damage to nearby plants.
DO try various environmental controls.
Mow your lawn at a higher height – this encourages more root growth and less visible root damage from grubs.
Water the lawn deeply, but less frequently to allow the soil to mostly dry out between waterings - Japanese Beetle eggs will not thrive in dry soil.
If you notice grubs, try a soil drench of parasitic Nematodes or Milky Spore.
The most vulnerable stage for control? From late July through early September, grubs are small and feed close to the surface. Targeting both adults (when they're feeding on leaves) and grubs (before they burrow deep for winter) helps break the cycle. Recognizing this schedule helps you time treatments with better results.
Make your yard more attractive for natural predators. Birds, spiders, and parasitic wasps feast on Japanese Beetles and reduce them for you! Attracting nature’s helpers can be simple:
Use Native Plants to create a thriving, diverse ecosystem that makes life tougher for Japanese Beetles.
Add water features and feeders to attract birds.
Keep a mix of mulch and bare soil to attract ground hunters.
Avoid using toxic “broad-spectrum” chemical sprays that kill beneficial insects.
Dealing with Japanese Beetles in Colorado is an ongoing effort, but a toolbox with different options helps limit the damage. Relying mostly on prevention and natural solutions protects pollinators and keeps your landscape safer for kids, pets, and wildlife.
If you’d like to nerd out more on Japanese Beetles, here’s a great article from the Old Farmer’s Almanac.
