The Colorado Department of Agriculture continues to work with Mesa County entities on efforts to eradicate Japanese beetles even as local officials work with homeowners.

“Property owners in the affected areas of Mesa County understand the importance of eradicating this invasive and destructive pest early, and Mesa County secured nearly unanimous consent from homeowners and homeowners associations to treat lawns for beetle grubs in those impacted neighborhoods,” said Melissa Schreiner, an entomologist with the Colorado State University Tri-River Extension Office. “It’s important to protect the Grand Valley from this voracious pest that feeds on leaves, flowers, fruit, shrubs, perennials and turf grass. Anyone suspecting the presence of the Japanese beetle should contact their local CSU Extension for more information.”

The Colorado Department of Agriculture has worked with the CSU Tri-River Extension, City of Grand Junction and Mesa County noxious weed and pest management to  support efforts to stop Japanese beetles.

“We have been working in partnership with a great local team on setting traps to measure the spread of the Japanese beetle in the affected area of Mesa County,” said Cheryl Smith, program manager in the Colorado Department of Agriculture division of plant industry. “Our plan is to treat turf before the grubs emerge and continue to trap and monitor numbers of Japanese beetles in the area to determine the best approach and efficacy of treatments.”

The first round of ground treatments started in mid-May and concluded at the end of June.

It’s estimated that 95 percent of those in the eradication zone agreed to the treatments. That means no additional enforcement will be necessary, although there’s a possibility of a second treatment this fall.

Traps were set beginning on May 16. About 400 traps were in place by the end of June. Local and state pest managers will continue to monitor the traps through summer and reevaluate this fall for next year’s eradication plan and area.

The Japanese beetle poses a threat to agriculture and ornamental horticulture on the Western Slope. The pests feed on more than 300 species of plants, many of which are essential to Western Colorado’s agricultural economy, including peaches, grapes, sweet corn, turf and many other ornamental plants in urban spaces, including turf grass.

The presence of this invasive beetle already has affected the green industry in Western Colorado. Some exports of plants out of Mesa County to areas without Japanese beetles — including New Mexico — have been denied by other states.

The Western Slope successfully staved off the beetle in the past. In 2002, a master gardener discovered the pest in the Grand Valley. The Upper Grand Valley Pest Control District eradicated the pest and reduced its population by 99 percent over five years. Japanese beetles reappeared in 2022, likely due to transport by an unlicensed landscape contractor who violated the Japanese beetle quarantine from Front Range counties.

Western Slope residents who suspect they have Japanese beetles should notify their local pest control district or Colorado State University Extension office. Those in Mesa County should contact the CSU Tri-River Extension at 244-1834.