Japanese beetles (Popillia japonica) are a species of invasive insect native to Eastern Japan. These pests were accidentally introduced to a nursery in Riverton, New Jersey in 1916. Within a matter of decades, the beetle population exploded throughout the United States, now home to millions of hungry beetles.
Japanese beetle populations continue to grow more severe, destroying crops, ruining landscaping, and creating skeletonized leaves. Their ability to consume precious plants and ornamentals makes them a hated insect species all over the U.S.
In this article, we’re going to explore the ways Japanese beetles wreak havoc on our lawns and discuss some prevention tips and control measures proven to make a difference.
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Japanese Beetles Identification
With their flashy green heads and linear bodies, Japanese beetles are relatively easy to identify even in a large yard.
- Adult beetles fly around with tan wings tucked under their carapace
- The head and thorax of the Japanese beetle is bright green and metallic in appearance
- Adult Japanese beetles have clubbed antennae, six legs, and a shiny brown abdomen
Japanese beetles are notoriously good fliers, although they are very slow while traveling from place to place. If you do have infestations of this pest around your home, it won’t be difficult to tell.
From their larval stage to their adult stage, Japanese beetles create damages at every stage of their lifecycle. They are perhaps best known for consuming the leaves and roots of ornamental shrubs, including some of our favorite plants:
- Rose bushes
- Grapes and grape vines
- Crape myrtles
- Birch and linden trees
Keeping Japanese beetles away from your property begins with understanding their grub identification.
Japanese Beetle Grubs
Japanese beetle grubs, sometimes known as white grubs, refer to the larval stage of the beetle’s lifecycle. Although they aren’t as conspicuous as their adult versions, these pests can be identified in a number of ways:
- White, yellow, or cream-colored larvae
- Grubs shaped in a ‘c’ with small heads and legs
- Brown patches of grass in a spotty pattern around the yard
Japanese beetle larvae consume grassroots and other small crops for several months as they grow. As the weather heats up and more rainfall soaks into the ground, the larvae will pupate into a brand new adult.
The Japanese beetle is easily one of the most destructive pests on the modern lawn. Proper grub control is critical for long-term beetle protection.
Japanese Beetles Lifecycle
The lifecycle of a Japanese beetle is carried out in four major stages: egg, larvae, pupa, and adult.
- From late spring to mid June, female adult beetles will lay their eggs roughly 2 to 4 inches deep in moist soils. Eggs will hatch within a few weeks to a few days, and the resulting larvae will immediately begin to feed on crops to progress through all five instars.
- Japanese beetle larva cannot move on their own right away, and rely on a combination of soil, water, and crop roots to survive.
- Larvae progress through the grub stage after their fifth instar, where they will go dormant for several days as they transform into adults.
- Adult beetles continue to feed on plants and other crops, and create even more beetles before the year is out. Some areas in the U.S. can see two or three beetle generations per season.
How to Eliminate Japanese Beetles
There are three major methods for getting rid of Japanese beetles: traps, approved insecticides, and natural products.
Japanese Beetle Traps
Much of the Japanese beetle population in your yard can be eliminated with some traps and baits.
One of the most popular Japanese beetle traps available on the market is the Beetle Bagger Japanese Beetle Trap – Kit. This trap attracts Japanese beetles with strong scents or chemicals, drawing them closer inside. Once adult beetles enter the bag, they will become trapped by the small opening at the top, killing them within a matter of hours.
A homemade trap can be made using a gallon container and some fruit cocktail. Fill a rinsed milk jug a third of the way with warm water, then add some yeast, old fruits, and other scraps to create a ‘honey trap.’ Japanese beetles will smell the fermented fruit cocktail, and get trapped inside the bottle (since they are not smart enough to fit back through the opening).
Traps alone aren’t always enough to get rid of serious infestations. These chemical pesticides have been proven to control Japanese beetles in a wide variety of environments. We recommend Permethrin SFR.
Grub control can be carried out by one of the following – we highly recommend Acelepryn liquid or Acelepryn granular. In fact, it’s the only product I use on my lawn and the 50+ lawns I service annually.
- Merit 0.5 G Insecticide Granules
- Milky Spore Lawn Spreader Mix
- Prime Source Imidacloprid 2F Select T/I
- CoreTect Tree & Shrub Tablets Insecticide
- Safari 20SG Systemic Insecticide with Dinotefuran
Some homeowners may not be as willing to use harsh chemicals on their lawns and gardens. In this case, there are some gentler methods of managing Japanese beetles naturally.
- Milky spore is an infectious disease that affects beetles during their larvae stage. Referred to as Paenibacillus popilliae, milky spore quickly disposes of vulnerable grubs by penetrating their rubbery outer flesh.
- Neem oil is known as a catch-all insecticide, especially for Japanese beetles. If your populations are relatively low, it’s a good idea to try hand-picking the beetles and dropping them into a pail of soapy water, neem oil, or cedar oil.
- Consider attracting natural predators to repel Japanese beetles without any substances. Birds like guinea fowl, beneficial nematodes, and other beneficial insects may slow beetle population growth during late spring.
- Soapy water can be sprayed on beetles and their plant prey to reduce feeding activity. Combine a gallon of water with a tablespoon of dish soap and a teaspoon of vegetable oil (so the spray sticks to the plant leaves), then apply to plants daily. Be sure to spray during the early morning to protect your plant leaves!
- Row covers may keep hungry Japanese beetles away from tender plants, especially in early spring or late fall.
Japanese Beetles FAQs
The ‘simple solution’ against Japanese beetles involves a full-press effort with cultural controls. Check out these frequently asked questions about Japanese beetles for a better idea of your pest control options.
What is the best way to get rid of Japanese beetles?
A combination of traps, chemicals, and natural remedies creates the best possible defense against a Japanese beetle infestation. Long-term applications will help to protect the vulnerable plants in your lawn and garden.
What is a natural way to get rid of Japanese beetles?
There are a few natural solutions for Japanese beetles during their spawning season. The use of neem spray or insecticidal soap in a spray bottle is a great natural solution. Many different types of traps and baits can be purchased online, as well as specific insecticides.
Will soapy water kill Japanese beetles?
Buckets of soapy water are a natural solution for small groups of Japanese beetles. Hand-picking and dropping beetles or white grubs into a jar are helpful, as well as manually spraying around the garden. Pay special attention to susceptible plants such as apple trees, grapevines, flowering trees, and rose bushes.
Will vinegar kill Japanese beetles?
Vinegar may help to dissuade Japanese beetles from your garden, but they may not be able to entirely remove a rooted infestation. Dropping the Japanese beetles into a bucket full of apple cider vinegar may kill the pests (similarly to dish soap), although it may take longer than mixtures such as rubbing alcohol. Vinegar works best as a hand-picking agent rather than a spray.