Japanese Beetle: Myth or Fact?

Myth: Japanese beetles only damage roses.

Fact: Roses are a favorite, but Japanese beetles have a much broader appetite. Larvae (grubs) feed on grass roots underground, while adults consume leaves, buds and flowers of more than 300 plant species, including grapes, Virginia creeper and fruit trees such as cherry, plum and peach. That range is why their presence is concerning for yards, parks, schools, golf courses and agriculture across Mesa County.

Myth: I’ve only seen a few beetles — it’s not a big deal.

Fact: Japanese beetles attract more Japanese beetles. Research shows feeding adults release scents that draw others to the same area, meaning a small number can quickly turn into a larger infestation.

Myth: Traps will take care of the problem.

Fact: Traps can attract additional adult beetles and may increase damage to nearby plants. While useful for monitoring and sometimes control, traps alone are not a guaranteed eradication tool.

Myth: Adult beetles are the only concern.

Fact: Grubs live underground and feed on grass roots, causing brown patches and turf damage. Effective management often requires addressing both life stages.

Myth: There’s nothing you can do without chemicals.

Fact: Non-chemical options can reduce damage, including drying down lawns from June through September, hand-picking adult beetles, using physical barriers and considering biological controls. These steps can be used alone or alongside targeted treatments when appropriate.

Myth: Japanese beetles can’t be eradicated.

Fact: Japanese beetles were eradicated in Mesa County between 2002 and 2008 through aggressive, coordinated efforts. Other states are pursuing eradication with positive results. Community participation remains key to success.

Understanding the facts allows residents to make informed, practical choices for their properties, families and pets. For details on the Japanese beetle life cycle, treatment options, insecticides, look-alikes and Mesa County history — plus how to participate in eradication efforts — visit Mesa County’s Japanese Beetle Eradication page.