The Japanese beetle is an invasive landscape pest that can cause damage to many varieties of plants including trees, turf, flowers and shrubs. According to the Colorado Department of Agriculture, it was originally detected in Colorado in 1995 and has been difficult to eradicate along the Front Range.

Metro District control practices

The Japanese beetle has been visible in our region for years, and Metro District staff periodically observes increased beetle activity. In addition to other pests and diseases, staff members have been trained to look for signs of the beetle’s presence throughout our extensive parks, parkways and open space systems.

As long as the beetle’s presence remains limited, the Metro District will proceed as it normally would — using best management practices to sustain plant health including spot treatments of insecticides only if necessary. Responsible irrigation, appropriate fertilization, timely aeration and strategic mowing and trimming practices will be the best line of defense for keeping this beetle and other pests at manageable levels. 

Identification of Japanese beetles

According to Colorado Parks and Wildlife, Japanese beetle larvae or grubs are “C” shaped. They live in the soil and feed on grass roots, among other plant species. They also have a pattern of hairs on their brown hind ends that form a small “V” shape, which distinguishes them from other grubs found in the soil and is visible under a 10-power hand lens.

Adult Japanese beetles, which feed on plants above ground, are approximately 3/8 inch in length with a dark metallic green head and metallic, dark tan wings. They also display two white rear tufts and five white lateral tufts of hair. 

Manage Japanese beetles on your property

There are a variety of state resources available to help you learn more about Japanese beetles and recommended management techniques:

For information about control measures on Metro District property, contact Dirk Ambrose, parks and parkways manager, at 720-240-5907 or dambrose@highlandsranch.org.