Japanese Beetles are Your Yard’s Worst Enemy — Here’s Why

Japanese Beetles are Your Yard’s Worst Enemy — Here’s Why

Summary: Japanese beetles are one of the most destructive yard & garden pests because they weaken plants. This blog discusses the habits and lifestyle of these beetles, then gives prevention tips. Pointe Pest Control eliminates pests with ease.

There’s no shortage of garden pests that want to ruin your yard, especially when the warm weather gives them energy. They chow down on the plants, burrow into the soil, and ruin the roots.

One of the worst yard pests is the Japanese beetle. This emerald-bronze beetle destroys gardens by weakening every vulnerable plant it eats. But how can these small beetles be such a huge threat to your yard? Furthermore, how can you prevent them?

Let’s find out by exploring the lifestyle of Japanese beetles to learn why they’re such a threat to our yards every summer.

The Life and Features of Japanese Beetles

If you ignore their destructive eating habits, Japanese beetles are some of the prettiest pests ever! They have coppery wing covers, shiny emerald bodies, and tufts of white hair around their abdomens. These beetles are 1/3 to 1/2 of an inch long, so they’re larger than most garden pests.

A fun fact about these pests is that they’ve only been in the U.S. since 1916, when they were brought over in the soil of various Japanese plants. Since then, Japanese beetles solidified their reputation as a frustrating garden and crop pest. Their life cycle just adds to the lore of their devastating dining parties, especially since it’s so unique.

Female Japanese beetles lay a few eggs at a time in damp grass. The white grubs stay in the moist soil to feed on roots. When the soil cools down, the grubs burrow deeper below the soil’s frost line and stay there for about 10 months. When the soil warms above 50º Fahrenheit in the next spring, the grubs pupate and emerge as adults in June.

Adult Japanese beetles are active from late June through September (1 month to go!). They only live up to 60 days, but those days are filled with breeding and chomping on plants, so they’re still a formidable pest.

A Devastating Diet

It’s time to talk about the core reason why Japanese beetles are so frustrating: their diet. Grubs eat decaying matter and grass roots, while adult beetles eat the plant’s leaves, flowers, and fruits. The adults aren’t picky with the types of plants they eat. They feed on over 300 types of ornamentals, flowers, and fruit trees.

Japanese beetles prefer plants that are in direct sunlight. They start feeding at the top of the plant and work their way down, chewing on the plant tissue to skeletonize the leaves. These beetles can also sniff out damaged plants and set their sights on the vulnerable greenery.

While they have a varied diet, Japanese beetles tend to eat from these plants and crops the most:

• Willows

• Roses

• Maples

• Shrubs

• Fruit trees

• Soft fruits

• Grapes

• Beans

How Do They Affect Plants?

So, now we know how Japanese beetles eat and which plants they like. But how does all of this actually affect our plants? Many plants won’t die from the damage, but they’re definitely weaker after a Japanese beetle infestation. These beetles are most destructive in large groups.

The most common result of an invasion is the skeletonized leaves turning brown and dropping off the plant. If the plant was already stressed — like from a lack of water or sunlight — it’ll be in worse shape after the beetles feed. Japanese beetles can also cause a lower crop or fruit yield when they invade those fruitful plants.

When they eat flowers, Japanese beetles impact the pollination process. After all, bees can’t pollinate when there aren’t any flowers to visit! Soybeans are another big concern when it comes to these beetles. When combined with other pest infestations, Japanese beetles can ruin the crops and lower the soybean yield.

The grubs aren’t innocent either. When they continuously feed on plant and grass roots, they ruin the plants right at their life source. The greenery can’t develop when their roots are chewed up and ruined. If your lawn starts looking patchy in otherwise normal conditions, it could be the work of beetle grubs.

The Very Hungry (and Annoying) Beetle

This subject is pretty timely, seeing as how Japanese beetle activity spikes from June through August. They’re still quite active at this point in the summer. The true impact of these shiny beetles completely depends on the makeup of the plant.

Japanese beetles can eat entire flowers and leaves if they’re more delicate. Grass that has a group of grubs (say that 5 times fast!) is less likely to survive a drought because of its weakened roots. The adults usually fly short distances to their next destination, but they can fly several miles when they need to find new food sources.

You may have heard of traps that capture the beetles in a specific area. However, these traps are more trouble than they’re worth. They can actually attract more Japanese beetles with the included pheromones, and the free beetles will turn to nearby plants for food. Trust us, there are plenty of ways to effectively prevent and eliminate beetles from your yard.

How to Prevent Japanese Beetles

If you have a green thumb, you might be wondering how to protect your plants and lawn from these destructive beetles. Preventing Japanese beetles is more about caring for your greenery and less about targeting the pests.

Our suggestions for preventing and treating Japanese beetles are:

• Care for the lawn — A healthy lawn is more likely to resist a beetle grub invasion. Water it regularly (without overwatering) and mow it at least once a week in the summer.

• Keep your plants healthy — On that note, make sure all plants in your yard are relatively healthy. Prune dead leaves and branches, pull weeds, and water the plants properly.

• Introduce other plants to the yard — Some plants are less appealing to Japanese beetles than others. Violets, begonias, lilacs, dogwood, forsythia, and holly are popular examples.

• Spot the signs — Beetles are easier to stop in the early stages of an invasion. Always keep an eye out for the signs, like skeletonized leaves, dead and unanchored patches of grass, and live Japanese beetles.

• Pick the beetles off by hand — Since they’re harmless to us, you can pick the beetles off by hand and place them in a bucket of soapy water to eliminate them.

• Use treatments for major infestations — A group of beetles will attract others, so they need to be treated immediately. Either use a spray (while following the instructions) that targets Japanese beetles, or contact a local pest control company to efficiently solve the problem.

Protect Your Flora & Fauna with Pointe Pest Control!

Some insects, like butterflies and honeybees, are beneficial visitors of flowering plants since they make a positive impact on the ecosystem. Japanese beetles and many other garden pests are more destructive than beneficial, especially this time of year. Pointe Pest Control is dedicated to protecting yards (and homes) from these types of invasive pests.

Our licensed technicians are well-versed in the life cycles of local pests, so we’re able to solve all kinds of pest issues with efficiency and care. Start the school year off with the peace of mind that comes with a pest-free home. Contact us for a free quote on our effective services today!

Citations

Japanese beetle. (n.d.). University of Illinois Urbana-Champaign. Retrieved August 13, 2025, from https://extension.illinois.edu/insects/japanese-beetle

Japanese beetles. (n.d.). Chicago Botanical Garden. Retrieved August 13, 2025, from https://www.chicagobotanic.org/plantinfo/pests/japanese-beetles

https://platthillnursery.com/how-to-get-rid-of-japanese-beeltes-in-your-garden/?srsltid=AfmBOortCCNdq6FzeLCUcG0IfCrGzefNej1VRM96WrpnUkf-xgX8rCfA

O’Neil, R. (2024, July 28). Illinois’ Japanese beetles: Here’s what you don’t know about them. WROK News Talk. Available at https://1440wrok.com/illinois-japanese-beetles-what-you-dont-know/ (Accessed on August 13, 2025).

Potter, D.A., Potter, M.F., & Townsend, L.H. (2006, January). Japanese beetles in the urban landscape. University of Kentucky: Department of Entomology. Available at https://entomology.ca.uky.edu/ef451 (Accessed on August 13, 2025).

SanSone, A.E. (2025, May 7). 9 expert-approved tips for getting rid of Japanese beetles. Southern Living. Available at https://www.southernliving.com/how-to-get-rid-of-japanese-beetles-11729613 (Accessed on August 13, 2025).