Japanese Beetle

Japanese Beetle Scientific Name: Popillia japonica

Japanese Beetle Facts

These clumsy, flying beetles can often be found bumbling around in the air or flying haphazardly into walls or windows. These creatures rarely intend to come inside, but they occasionally find their way inside homes. Originally native to Japan, these beetles were unintentionally introduced to America in the 1920’s and have thrived under the warm, hospitable climates. They are frequently found in southern states or across the Mexican border, but are also an important aspect of Ohio agriculture and are particularly common to Michigan.

Japanese beetles, adults and larvae, can sometimes become a problem for garden owners as they feed not only on plant leaves, but also on plant veins, which can lead to destruction of the plan itself. These small, green beetles are prevalent in June and July, after laying their eggs in soil a few weeks prior. Pest control is usually a combination of traps and insecticides, and is easily manageable.

Japanese Beetle Identification

A fully mature Japanese beetle is a very interesting looking creature. They are a magnificent metallic green with a round, oval body and short legs. They have wings that encase their backs for flight. Males can be identified by the sharp, white tips on their front legs. Females have a similar marking, only more rounded. Knowledge in differentiating between the genders of Japanese beetles you have may help you assess whether there is a chance of reproductive phases in your garden or home. Pest control methods should be applied accordingly.

Japanese Beetle Habitat

Japanese beetles are herbivores and eat over 400 types of plants in America. They are also “skeletonizers,” which means that they predominantly eat the veins in leafs, rather than the leaves themselves. This can cause many problems, as most plants often die when their veins are damaged, as it inhibits transport the water and nutrients required.

Japanese beetles have a wide dietary selection and are often found in gardens or woodlands and swamps all across America. Where natural vegetation thrives, a combination of warm conditions can create an abundance in population. They are found in significant numbers in certain states in the north and generally all across the south in more manageable conditions.

Grubs (the Japanese beetle larvae) require their own specific environment. These are usually earthy areas with healthy soil and strong root systems. Grubs may fly to other desirable areas once they have matured; they typically require a different habitat than that of the adult species and the females will travel to these habitats to lay their eggs.

Life Cycle of Japanese Beetle

Like other beetles, Japanese beetles have four main stages in their life cycle. This includes eggs, larvae, pupae and adulthood. Females will travel to areas with nutritious soil in which to lay their minute, oval eggs. Once the eggs hatch, they become larvae or gurbs.

These white grubs can be a pest in their own right. During this phase, larvae require several meals, after which shedding occurs. This happens several times until they reach the pupal phase. Grubs feed on root systems and require these regular meals, often times feeding for up to twelve weeks. Grubs are larger than eggs but smaller than pupae and can grow up to about two inches long.

The Japanese beetle pupa, which is the third stage, will usually sport reddish brown or copper-brown colorings with a structure more similar to their adult counterparts. During this time, they have transitioned from white, to a cream color and grow in thickness but not in length. If the conditions are wet and warm, this process can accelerate from weeks to just a matter of days.

Adults are a magnificent metallic green and have a strong oval shape which is significant to many beetles. The abdomen will now have five white tufts, and the males also have a sharp tip on their front legs, while the females are more rounded or curved in shape.

Japanese Beetle and Humans

Japanese beetles have continued to grow in numbers at a steady rate since their introduction into the United States in the early 20th century. They are a known problem in localized areas, but their numbers are increasing this threat more widely across the continent. In large populations, they can create devastating effects on environments and create issues for entire towns that have to impose pest control as a whole in order to be effective.

Japanese beetles have a distinct population line from Michigan through Wisconsin, Illinois and further south to Alabama, but can be found in many other states, as well. They are considered a contributor to the agricultural landscape in Ohio, where they prevent certain plants and weeds from growing wildly, but their increasing numbers are causing concerns in the eastern regions of the state and neighboring states.

Japanese Beetle Control

If an occasional Japanese beetle is found in your home or garden, you can hand pick them and destroy these scouts by dropping them in soapy water. This will help prevent others from arriving. You can also research which plants you have in your garden, as Japanese beetles are attracted to only 400 of some few thousands types of plants.

Trapping: You can trap Japanese beetles by using for a floral or pheromone lure, which can be purchased from many outdoor or gardening stores. These bait the beetles and then trap them for your immediate disposal. This method should be exercised with caution as it can also increase the amount of Japanese beetles in an area and is usually carried out on a large scale.

Insecticides: You can remove both adults and grubs by spraying plants in your garden with insecticides that will kill off offending pests when they try to eat your plants. You should anticipate their arrival in June or July of each year and apply the insecticides about 20 days before then. Some sprays may need to be applied every week thereafter.

You should monitor your plants for signs of damage under the leaves, especially at the veins. For the existence of grubs, monitor root systems and underneath the plants for white eggs, which can be removed and the affected area treated with insecticides.

Japanese Beetle Entomology

Japanese beetles belong to the animalia kingdom, and are divided into the arthropoda phylum. They are also a member of the large insecta order but can be found under the coleoptera family, which has it’s own genus, the popillia. They are specific to the P. Japonica species from which their name derives.