Are the Japanese Beetles on My Tree Harmful? Here's How to Protect Your Trees from These Pests

Have you noticed that your tree leaves are full of holes and that your grass looks a little bare this summer? A closer look may reveal that little metallic green and copper beetles have taken up residence in your yard for their summer vacation! The Japanese beetles on your tree are harmful because this invasive species eats away at leaves while its larvae munch on grass roots — leaving your yard susceptible to other diseases and pest infestations. The tree care experts at Monster Tree Service explain why Japanese beetles are bad for trees and effective methods of prevention and treatment. Learn how to get rid of Japanese beetles and protect your trees from these pests.

What are Japanese Tree Beetles?

The Japanese beetle, or Popillia japonica, is an invasive insect that feeds on trees, shrubs, and other plants. These beetles were discovered in the early 1900s and are identified by their metallic green heads and copper bodies. Japanese beetles emerge from the soil at the beginning of the summer season. They begin life as white grubs that live under the ground and feed on grass roots, and they mature into 1/2 inch adult beetles that live in trees and eat leaves. Japanese beetles enjoy munching on the leaves of over 300 plant species and sunny yards with dense foliage. They are most attracted to rose bushes, birch, maple, elm, cherry, apple, and plum trees.

Why are Japanese Tree Beetles Bad for Trees?

While Japanese tree beetles may look innocent enough at first glance, they are actually terrible for the health of your trees. These beetles defoliate trees, meaning they eat away at a tree's leaves. When a tree doesn’t have enough foliage, it becomes stressed and is more susceptible to other diseases and pest infestations. While this insect has natural predators in its native Japan, there are few predators in North America to prevent its destruction. So, populations can multiply and destroy a yard by the end of the summer season.

How to Get Rid of Japanese Beetles in Trees

Remember That Prevention is the Best Defense

The best way to protect your trees and yard from Japanese beetles is to prevent them from taking up residence in the first place. Consider adding plants to your yard that beetles are not attracted to, such as lilacs, dogwood trees, magnolia trees, and pansies. Avoid plants like roses, red leaf and fruit trees which attract beetles. Other plants like geraniums act as a natural defense against Japanese beetles, paralyzing them and leaving them helpless to predators. Repel beetles early on to prevent a larger hassle later in the season. While traps may seem like suitable prevention methods, don’t use them. Many products contain pheromones that will actually attract more beetles to your yard.

Deter With Smells

Japanese beetles are attracted to sweet smells, including roses and fruits. Deter them from your yard by fostering aromas that repel them. Garlic, cedar, chives, and catnip are bitter scents that keep beetles at bay. Consider planting these scents around susceptible plants to deter beetle infestations.

Attract Natural Predators

Japanese beetles don’t have many natural predators in North America, so pest infestations can quickly multiply and damage your trees. To protect your trees from these pests, take measures to attract natural predators to your yard. Install birdhouses and feeders to entice cardinals, robins, and crows to visit your yard and snack on beetles. Tachinid flies will also kill beetles without damaging other plants in your yard. Attract them with dill, fennel, and mint plants.

Pick Japanese Beetles Off Trees and Shrubs

If you already have a Japanese beetle infestation in your trees and shrubs, the best way to remedy the situation is to handpick the beetles off your plants and kill them in a mixture of water and dish detergent. Beetles are most active in the early evening, so begin the process around 7:00 or 8:00 PM to catch as many as possible. If you’re afraid of creepy crawlies, use gloves to prevent direct contact with the beetles.

Use Organic Pesticides Like Neem Oil

Neem oil is a nontoxic insecticide made from the seeds of the neem tree. Unlike harsher chemicals, neem oil doesn’t pose a high risk of harming plants or humans during application. However, it is effective at killing Japanese beetle infestations. When adult beetles ingest neem oil, they pass it on to their eggs which eventually die after hatching — eliminating the infestation and preventing rapid beetle population growth. It is best to spray neem oil early in the season before adult beetles mate. Other insecticides, including carbaryl and acephate, can kill beetles but will also kill helpful insects, such as pollinators. Consult a plant health care professional before using chemical insecticides.

We’ll Help You Keep Your Tree Beetle Free!

While prevention is the best method to protect your trees from Japanese beetles, pest infestations can strike fast! Our plant health care experts at Monster Tree Service can assist with insect and disease management to eliminate pests and keep your tree beetle free! Get a free quote today. Contact your local Monster Tree Service for advice and assistance with your tree health care needs.