Japanese Beetles

The Japanese beetle is a serious threat to foliage throughout Minnesota, as they feed on approximately 300 plant species. They first showed up in New Jersey in 1916 and have been spreading ever since. Most of the eastern U.S. is able to control the beetle due to soil-inhabiting protozoans, but these protozoans are not present in Minnesota.

Not all Japanese beetles are threats, though. Those that are dangerous can be identified by their green heads and brown wings or they may appear to be off white or green in color. They are approximately 3/8 inches long and mostly found on plants. The smallest species can look brown or black in color and can be found in areas where there is a high amount of organic matter.


Japanese beetle larvae, also known as grubs, look like c-shaped worms. They tend to be found underground, feeding on grass roots. They have also been known to feed on the roots of beans, corn, strawberries, and tomatoes. You can scout for grubs to see if there is a problem in your area. Even if you don’t see the grubs themselves, you can roll back a dead patch of grass like carpet and see the missing grass roots. You can then look under an adjacent green area and find grubs feeding.

Adults lay eggs in July for the grubs to begin feeding in August and September. They remain deep in the soil until they begin feeding again in April and May. They reach adulthood in June and the egg laying process begins again in July. Once they are adults, they can fly long distances to feed on leaves. Just because there are a lot of adults feeding does not mean the nearby turf is infested with grubs.


Fortunately, our Minneapolis tree service can apply insecticides for you. We inspect the area for the problem, look at the leaves being fed on, etc. We can then determine the best course of action. Different insecticides can be used on adults than what is used on grubs and are typically applied between mid-July and the end of September.

In an effort to eradicate the beetles, some individuals feel that Japanese beetle traps will be a more cost-effective solution. The fact is that they are not. This is because the beetles are more likely to fly toward the traps than actually be trapped. This can result in a higher concentration of the beetles on the property, resulting in more dead foliage. More dead foliage can result in a higher expense.

One useful tip, however, is if you are adding to your landscape at any point, you may want to include plants that Japanese beetles do not like so well, such as pine trees, red oak, lilac, American elder, white ash, spruce, and white poplar, just to name a small number. This can actually reduce beetle populations.

Contact A Knowledgeable Tree Service

When it comes to controlling Japanese beetles, whether through insecticides or planting other species of plants the beetles don’t like, you need a tree service that knows exactly what to do for a competitive price. To learn more about how we can help you and to receive a free quote, call us at 1-800-331-3919.