How Are Japanese Beetles Harmful?

Japanese beetles can kill trees by eating their leaves. Photo by Julie Weatherbee.

Japanese beetles can be very destructive because during the short Japanese beetle season, because they devour and kill much vegetation. They are a threat to gardeners and farmers everywhere because of their voracious appetite.

Japanese beetles come out in force in early summer and they have a tendency to swarm together. Moving from tree to tree and plant to plant, the huge population of Japanese beetles can overwhelm and destroy quickly.

They eat the fleshy part of leaves, leaving only the veins behind, in a process called skeletonizing. This leaves the trees with no way to harvest solar energy. Trees rely on photosynthesis for generating energy for life, and without their leaves they are vulnerable to disease and death.

Japanese beetles also love the floral scents of many flowers and buds, especially roses. A Japanese beetle infestation comes on fast and they can quickly eat holes through the buds of flowers. Every gardener dreads the sight of Japanese beetles in his garden.

Another way they can be harmful is that Japanese beetles sometimes bite people and pets. They do not actively seek out people or animals, but if they come across them they do have the ability to bite.

Japanese beetles may also be considered harmful because they are an invasive species to America, having originally evolved in Japan. Their presence may upset the natural ecosystem of an environment because they are so hardy and widespread, offsetting other insects that may thrive in their absence.