Japanese beetles are one of Colorado’s most persistent and destructive garden pests. You’re not alone if you’ve noticed skeletonized leaves, chewed flowers, or swarms of shiny, green-backed beetles clinging to your plants. These invasive insects can quickly turn a thriving landscape into a damaged mess. Fortunately, with the right approach and a clear understanding of how to get rid of Japanese beetles, they can be controlled.
At Westside Grounds, we’ve spent more than 25 years helping homeowners protect their landscapes from pests like Japanese beetles. Our knowledgeable team understands how these insects behave, when they’re most active, and which methods work best to control them. From preventive lawn treatments to full-season pest management, we offer proven, professional solutions tailored to your yard’s needs.
In this post, we’ll walk you through how to get rid of Japanese beetles, spot them early, and keep Japanese beetles away.
What Are Japanese Beetles?
Japanese beetles (Popillia japonica) are an invasive pest species introduced in Colorado in the 1990s. While relatively small, they cause outsized damage to turfgrass, garden plants, trees, and shrubs. Adults have metallic green heads and copper-colored wings, and are most active in Colorado from late June through September.
Their grubs live in soil and feed on grass roots, while the adults emerge in summer to chew on foliage, flowers, and fruit. This two-stage threat makes them particularly difficult to control without a long-term strategy.
How to Get Rid of Japanese Beetles
Eliminating Japanese beetles takes a multi-step approach. Because these pests cause damage above and below ground, treating the adult beetles and the grubs in your soil is essential. Below are several methods to reduce their population and protect your plants.
Hand-Picking
One of the simplest and most effective early-season strategies is to remove beetles by hand. Although time-consuming, hand-picking can significantly reduce the number of beetles in your yard, especially before they attract more with their pheromones. Drop them into a container of soapy water to prevent them from flying away.
Traps
Japanese beetle traps are readily available at garden centers, but must be used cautiously. These traps use pheromones to lure beetles, so they often attract more beetles to your yard than they catch.
If you use a trap, place it far from your most vulnerable plants and away from outdoor seating areas. Traps are most effective when monitored closely and emptied regularly. They should supplement, not substitute for, other control methods.
Insecticidal Soaps and Organic Sprays
Several insecticidal sprays are available to control adult beetles on ornamental plants and flowers. Organic options like neem oil and pyrethrin-based sprays are popular because they are relatively safe for beneficial insects when applied correctly.
Neem oil, in particular, affects beetle feeding behavior and reproduction when ingested. It is best applied every few days during peak beetle season. Always follow label directions and spray early in the day or late in the evening to minimize exposure to bees and other pollinators.
Synthetic Insecticides
For more severe infestations, contact sprays with active ingredients such as carbaryl or bifenthrin can offer short-term control of adult beetles. These insecticides are more potent and often have a longer residual effect. However, they must be applied carefully to avoid harming non-target insects and surrounding plants.
Beneficial Nematodes
Adult beetles are only part of the problem. The grubs live in your soil and feed on grass roots. Reducing the grub population is key to preventing future outbreaks.
Beneficial nematodes are microscopic worms that attack and kill grubs without harming plants or people. They are applied to lawns using water and are most effective in moist, well-aerated soil.
How to Keep Japanese Beetles Away from Your Property
Preventing Japanese beetles before they become a problem is the best way to protect your plants, trees, and lawn. These highly mobile pests can be difficult to manage once they’ve established a presence. By using proactive strategies, you can discourage them from targeting your yard.
Keep Your Lawn Healthy
Beetles are more likely to lay eggs in stressed or thinning turf. Maintaining a thick, healthy lawn makes it harder for larvae to take hold. Proper fertilization, regular mowing, and scheduled aeration contribute to stronger root systems and denser grass coverage.
Westside Grounds offers yard care plans that include weed control, fertilization, and soil conditioning, all of which support your lawn’s resistance to pests.
Use Resistant Plants in Your Landscape
Some plants are highly attractive to Japanese beetles, including roses, grapes, linden trees, and Japanese maples. While you don’t need to avoid these entirely, consider mixing in plants that beetles tend to avoid. These include:
- Boxwood,
- Dogwood,
- Lilac,
- Forsythia,
- Magnolia, and
- Holly.
Choosing less appetizing plants helps reduce the chance of your landscape becoming a feeding site.
Monitor Early and Act Quickly
Japanese beetles often arrive in waves. The first few beetles release pheromones that attract others. If you see one or two on your plants, don’t wait. Remove them immediately to prevent further buildup. Early intervention can stop a small problem from becoming a full-blown infestation.
Avoid Overwatering in Summer
Japanese beetles prefer to lay eggs in moist soil. Keeping your lawn a little drier during the egg-laying months can make it less inviting for beetles looking to reproduce.
Apply Grub Control Treatments in Late Spring or Early Fall
Because Japanese beetle grubs develop underground before emerging as adults, treating your soil at the right time can significantly reduce their population. Westside Grounds can assess your lawn and apply control treatments at optimal times for maximum impact.
Work with a Professional
Consistent lawn care and integrated pest management are your strongest long-term Japanese beetle control tools. Westside Grounds offers customized maintenance plans that include preventative treatments, plant monitoring, and seasonal adjustments to keep beetles and other pests from taking over.
Professional Japanese Beetle Control Services in Colorado
Japanese beetles can quickly overwhelm even the most dedicated gardener. If DIY methods aren’t enough or if you want a more proactive, consistent approach, Westside Grounds can help.
Our experienced team understands how to kill Japanese beetles and keep them away with innovative, seasonally timed strategies. We offer comprehensive residential and commercial property options, from eco-friendly treatments to professional yard maintenance.
We begin with a property assessment and create a customized plan targeting adult beetles and grubs below the surface. Our goal is not just to control the current infestation but to protect your plants, turf, and garden from future outbreaks.