You Know Japanese Beetle Season is Here if You Find Lacy-Looking Leaves on Your Plants and Trees

If your trees or shrubs have started looking a little lacy this summer, you're not imagining it. Japanese beetles are active across Columbia and Mid-Missouri right now, and they're one of the most common, and most visible, pest problems we treat during the summer season. 

What Are Japanese Beetles?

Japanese beetles are an invasive insect that commonly show up in our area during the summer, usually from June through August. They were first found in North America in New Jersey in 1916 and have since spread into many parts of the United States, including Missouri, where they became established by around 1970.

Peak activity in Mid-Missouri runs from June through August, with adults typically emerging from the ground in late June or early July and feeding heavily through the summer. Their resurgence varies from year to year. Some years are mild, while other years populations are much heavier. Unfortunately, we don't know exactly how bad each season will be ahead of time.

Why Are They Invasive and Detrimental to Trees?

Japanese beetles are considered invasive because they’re not naturally found in our region, and were introduced with few native predators to naturally control their populations. Our native plants have not developed alongside them, so their natural resistance is often lower than that of plants from the beetle’s native region.

Adult Japanese beetles eat the soft tissue between the leaf veins, which gives damaged leaves a lace-like or skeletonized appearance. This damage is often very noticeable and can make trees and landscape plants look rough quickly during heavy beetle activity.

Heavy feeding can stress a tree by reducing the amount of healthy leaf tissue available for photosynthesis. This can affect the tree's appearance, reduce ornamental value, and add stress to trees that may already be dealing with heat, drought, root issues, disease pressure, or other problems.

Most healthy, established trees can tolerate some Japanese beetle feeding, but repeated heavy feeding or damage to already stressed trees can be more concerning, which is part of why we recommend a proactive plan for trees under other kinds of stress.

How Ratliff Tree Approaches Treatment

Our treatment approach is designed to reduce feeding damage and protect the appearance and health of the tree. The goal is not to eliminate every beetle from the property. Japanese beetles are highly mobile and can continue flying in from surrounding areas, so even treated trees may still see some activity or light damage. Treatment helps reduce the impact.

Our Foliar Treatment Program

We use foliar treatments to control adult beetles and reduce feeding damage. These can be done reactively once beetles are active, usually with one or two applications during peak activity. Customers who want more consistent protection can also opt for a monthly treatment plan through the growing season. This follows the same cadence as our Full-Season Ornamentals Check & Treat Program, which provides monthly monitoring and treatment from April through September.

Another benefit of a regular foliar program is that we're already monitoring the tree during the growing season. When appropriate, we can often watch for other issues, such as fungal leaf problems or other insect activity, and address those during the same visit when it fits the treatment plan.

Do foliar treatments against Japanese beetles hurt other plants or pollinators?

We have treatment options that can be used around blooming trees while being mindful of pollinators. Many insecticides can be harmful to bees if used incorrectly, so our approach is to select the appropriate, pollinator-conscious treatment option to reduce that risk while still managing the beetle problem.

Contact Ratliff Tree for a Tree Health Consultation

Because we don't know exactly how bad each season will be ahead of time, customers with a low tolerance for visible leaf damage should consider a preventive treatment plan before damage gets heavy.

Ratliff Tree's Plant Health Care team can evaluate your property and recommend a treatment plan that fits your trees and your tolerance for damage. Request a property consultation or call us at (573) 446-2266.