The homeowner’s guide to controlling Japanese Beetles


Japanese Beetles are widely considered one of the most damaging and hard to control pests in the garden. Adults have oval-shaped metallic green bodies and bronzecolored wings. In midsummer when eggs hatch, young grubs emerge ready to feed. Grubs are creamy white, C-shaped, and one inch long when fully grown.


Adults feed on more than 300 species of plants, ranging from roses to poison ivy. They begin on the upper surface of foliage, chewing out tissue between the veins and giving the leaf a skeletonized appearance. You may also notice large, irregular holes in leaves. Odor and location in direct sunlight seem to influence the beetle’s plant selection. From midsummer into late autumn, grubs feed on the roots of various plants and grasses, often destroying large patches of lawn.


As with most pest infestations, early prevention is your best line of defense. Here are some things to keep in mind at any stage:

  • HEALTHY PLANTS: Maintaining hardy, healthy plants is one of the best defenses against infestation.
  • INSECTICIDE for ADULT BEETLES: An application of Systemic Insect Drench in May is normally a very effective deterrent, as is Eight if you see any activity during the summer.
  • Several applications may be necessary during the active stage.
  • THE NATURAL ROUTE: Dr Earth Insecticide, an organic solution, is a contact control that requires multiple applications. Do not apply during the heat of the day to avoid potential damage to foliage.
  • GRUB CONTROL: Try Kill-a-Grub to limit the number of beetles you encounter next spring.

And remember, our Altum’s yard and garden experts are always here to help.
You can pick up the phone and call 317.733.GROW or Ask an Expert for a diagnosis and friendly advice.