Japanese Beetles in Your Garden and Yards

Japanese beetles are native to Japan, hence their name. They were first discovered in Japan in the late 19th century. However, the exact origins of Japanese beetles are not entirely clear. It is believed that they may have existed in other parts of Asia before being introduced to Japan.

In the early 20th century, Japanese beetles were accidentally introduced to North America. It is believed that they arrived in the United States in a shipment of iris bulbs imported from Japan to a nursery near Riverton, New Jersey, in 1916. From there, the beetle established populations and spread rapidly throughout the United States and Canada.

Japanese beetles are now considered a major pest in North America, causing significant damage to a wide range of plants and crops. They are particularly destructive in their larval stage when they feed on the roots of grasses, and as adults, they feed on the foliage, flowers, and fruits of various plants.

Efforts have been made to control the spread and impact of Japanese beetles, but they continue to be a widespread and persistent pest in many parts of North America.

Japanese Beetle Appearance

Japanese beetles are relatively small insects with distinctive markings. Here is a description of the Japanese beetle appearance:

  1. Size: Adult Japanese beetles typically measure around 0.6 to 0.7 inches (15 to 17 mm) in length. They are comparable in size to a typical penny or dime.
  2. Body Shape: Japanese beetles have an oval or elongated shape with a rounded back.
  3. Color: Their bodies have a metallic green hue, which can vary in intensity. The coloration often appears iridescent, reflecting different shades of green.
  4. Head: The head of a Japanese beetle is black with a pair of prominent white tufts of hair on each side. These tufts are known as “pencil erasers” due to their appearance.
  5. Wing Covers: The wing covers, also called elytra, are a shiny metallic green. They have distinct rows of white tufts of hair running down each side. These rows of white hairs serve as distinguishing marks.
  6. Underside: When viewed from the underside, Japanese beetles have a shiny, metallic green abdomen.

It’s worth noting that the appearance of Japanese beetles can vary slightly between individuals, and their colors may change as they age or if they are disturbed. However, the metallic green body with white tufts of hair is the most characteristic feature of adult Japanese beetles.

Control Methods of Japanese Beetles

  1. Plant Selection: Japanese beetles have certain preferences for plants. Avoid planting their favorite foods, such as roses, linden trees, grapes, and raspberries, as they are likely to attract more beetles. Instead, choose plants that are less appealing to them.
  2. Handpicking: This is a labor-intensive but effective method for small infestations. In the early morning or late evening when the beetles are less active, you can physically remove them by hand and drop them into a bucket of soapy water.
  3. Trap Bags: Japanese beetle trap bags use pheromones to attract beetles into a bag where they become trapped. While they can help reduce the number of beetles in your garden, they can also attract more beetles from neighboring areas. Use traps strategically and away from the plants you want to protect.
  4. Insecticides: Insecticides can be used to control Japanese beetles by killing them or preventing then from destructing your gardens and lawns.

Best Pest Control Plan

Our InsectaShield® Plus Japanese Beetles combines foliar applications when the beetles first arrive and the use of Systemic Insecticides that are absorbed by the plant.  The insecticide is taken up be the roots and transported throughout the plant, making it toxic to the beetles when they feed on the plant.