Japanese Beetles

Japanese beetles are not native to Washington state. Outside of their natural ecosystem in Asia, Japanese beetle populations increase quickly if they are not controlled. Outbreaks of Japanese beetles are a problem because adult Japanese beetles eat the leaves of over three hundred different types of plants, flowers, and fruits, while the grubs (larvae) eat turfgrass roots. Japanese beetles don't bite or spread disease to humans.

Japanese beetle eating a leaf.
Photo credit: "Japanese Beetle" by Benimoto is licensed under CC BY 2.0.

The Washington State Department of Agriculture (WSDA) is working on a multi-year program to remove Japanese beetles. Eradication includes mass trapping, insecticide treatment, and establishing a quarantine to prevent the spread of the beetles and protect gardens, lawns, farms, and our natural resources. WSDA also encourages the public to report sightings and help prevent the spread of this pest. 

WSDA plans to treat infested areas in Yakima, Benton, and Franklin counties in spring and summer to address the outbreak of Japanese beetles. The plan involves applying the liquid larvicide Acelepryn to soil. The granular version, Acelepryn G, may also be applied to soil. Both Acelepryn G and Acelepryn are approved for use in residential and commercial areas. Visit WSDA’s Japanese beetle page to see if you are in a treatment area and give consent to have your property treated.

How to Stop the Spread of Japanese Beetles

Washington state uses an integrated pest management approach to reduce the spread of Japanese beetles. This includes:

  • Monitoring for the beetles with traps that attract the beetles.  
  • Teaching homeowners how to identify and report beetle sightings.   
  • Treating for the beetles - with property owner consent - using the least toxic methods available.  

Washington State University Extension also teaches homeowners how to self-treat Japanese beetle detections. See WSU Extension's Japanese beetle identification and treatment handout (PDF).

What are Acelepryn G and Acelepryn?

Acelepryn G is a dry granule pesticide that is spread on the ground and watered in. When exposed to water, Acelepryn G absorbs into the soil. Acelepryn is the liquid form of Acelepryn G and is sprayed on the leaves, bark, and soil of plants. 

These products kill both the larva and adult Japanese beetles when they eat or come into contact with it. Acelepryn G and Acelepryn are also used to control other insects like grubs, caterpillars, and weevils. These pesticides are not a risk to mammals, birds, or fish.

Japanese beetles eating a flower.
Photo credit: Karla Salp, WSDA (2021)

EPA approved applications of Acelepryn G and Acelepryn in areas including turfgrass on athletic fields, parks, playgrounds, and lawns, and on flower beds and bushes planted around homes, schools, and businesses.

What ingredients are in Acelepryn G and Acelepryn?

Acelepryn G and Acelepryn are commercial pesticides with the active ingredient chlorantraniliprole. Acelepryn G contains limestone clay and an ingredient that binds the active ingredient to the clay. Acelepryn contains very small amounts of two preservatives (1,2-benzisothiazol-3(2H)-one; and bronopol). Although some people are sensitive to preservatives, allergic reactions have not been reported in people exposed to Acelepryn.

EPA reviewed Acelepryn G and Acelepryn and placed these pesticides in the reduced-risk category. That means they pose less of a risk to human health and the environment than other pesticides used for the same purpose.

What are the health concerns of Acelepryn G and Acelepryn?

When used as directed, Acelepryn G and Acelepryn aren't dangerous for people. Washington State Department of Health toxicologists have reviewed the active ingredient in these pesticides and concluded that they pose a very low concern for health. The active ingredient has not been found to cause allergic reactions. The active ingredient is approved for use on produce such as leafy vegetables, grapes, cucurbits (gourd vegetables), potatoes, rice, pome fruit (apples and pears), and stone fruit (peaches and plums). Additionally, EPA concluded that Acelepryn G and Acelepryn are not dangerous to domestic animals, including dogs.

No symptoms or illness have been reported following applications of Acelepryn G or Acelepryn in Washington or Oregon.

EPA did not review potential health risks associated with Acelepryn G or Acelepryn use in home vegetable gardens or home orchards because these pesticides are not intended for these settings. However, because EPA approved the active ingredient for use in a wide range of commercial food crops, we don't expect a health risk to occur in these scenarios. Take steps to prevent run-off to home or school vegetable gardens when watering Acelepryn G into nearby soil. Learn more about preventing runoff from EPA's Reducing Pesticide Drift.

The active ingredient in Acelepryn G and Acelepryn is harmful to aquatic invertebrates such as crayfish and water fleas. Do not apply these pesticides near bodies of water to prevent runoff into those areas.

Public Health Recommendations

Acelepryn G and Acelepryn have an excellent safety record when used as directed. If you're still concerned, you can limit direct contact with the product by following these tips:

Talk to your health care provider if you have health concerns related to Acelepryn G or Acelepryn.

More Information

Japanese Beetle, WSDA - Learn more about identification, signing up for free beetle treatments, homeowner self-treatment options, how to report a sighting, and how to stay informed.

Japanese Beetle Eradication Handout, WSDA (PDF)


Content Source: Pesticide Program