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Japanese Beetles Eating Your Plants? How to control them?

by Danny White

The relationship between general lawn management and the Japanese beetle is a complex one. These scarab beetles are not known for any particularly destructive habits in their native Japan. On the other hand, North America lacks the natural predators necessary to keep these pests under control.

Luckily, there are a number of tried and true methods of keeping these pests from destroying the hard work you’ve put into your garden.

Identifying Japanese Beetles

These small scarab beetles are known for causing a large amount of damage to crops within a small period of time.

While they originated in Japan, where natural predators keep them from being a problem, their introduction to the United States was fraught with mishaps.

In fact, their introduction to the West was entirely accidental, yet it yielded disastrous results for plants and vegetation. Feeding on over 300 species of plants by first skeletonizing their foliage, their larvae simultaneously work to feed on grass roots.

Physical Appearance

These are small bugs, roughly only 1/2 inch in length. They are more easily identified by their coloring, consisting of:

  • tan wings
  • copper backs
  • white abdominal hair
  • metallic blue-green heads

Recognizing Japanese Beetle Damage

While it is likely that there are many pests potentially damaging your garden, there are a few key signs that point toward Japanese Beetles.

Although Japanese Beetles have relatively short lifecycles, their larvae remain underground for the first 10 months of their lives. This can make it extremely difficult to know when you have fully gotten rid of the pests.

Skeletonized Plants

These beetles work to upset one’s lawn care in various ways. The first of these ways being by skeletonizing plants and flowers. Essentially, this is the practice of eating everything but the veins of each plant the species has infested. 

A plant that has been damaged this way, leaving nothing but it’s “skeleton”, has likely been attacked by a Japanese Beetle. 

Unhealthy Grass

Because the larvae gnaw at the roots of grass during the first 10 months of their lives, suddenly patchy and brown grass can indicate the presence of Japanese Beetles.

Getting Rid of Japanese Beetles

Once you have properly identified your Japanese Beetle infestation, there are a number of known ways to rid yourself of the pests.

1. Cover Your Plants

This is one of the last resort methods we would recommend, but it is one of the most effective. Utilizing row covers on your plants during the summer will keep the beetles from being able to reach them. However, one should keep in mind that this practice will also keep pollinators from being able to reach their plants.

2. physically Pick Them

Another method that may not seem so ideal but is extremely effective is hand-picking the beetles from your plants. Although this is time-consuming, systematically getting rid of each beetle one-by-one is extremely effective.

3. Insecticide Spray

Insecticide spray is highly effective at getting rid of Japanese Beetles. Those who do not wish to use the sprays on their garden can instead opt to make their own more natural version with vegetable oil, water, and rubbing alcohol.

4. Plant Geraniums

Geraniums are naturally attractive to Japanese Beetles. However, the chemicals emitted by geranium blossoms effectively cause them to get dizzy and fall off of the plant.

Not only does this keep the beetles away from other plants, but it allows one a window to quickly dispose of the beetle.