It seems like there are a million pests that can invade your garden, from aphids to spider mites, cutworms to Japanese beetles. Japanese beetles in particular can be a frustrating garden nemesis because they’re not native to the United States, and they don’t have the natural predators required to keep them under control. Japanese beetles are native to Japan, where they do not present as great a problem for gardeners or farmers.
If you think that your garden is falling victim to Japanese beetles, it’s important to know how to identify the signs of an infestation and how to get rid of Japanese beetles. The experts at Platt Hill Nursery have a range of remedies. We can help you decide how to naturally get rid of Japanese beetles and or which commercial products to use.
The following Japanese beetle guide can help you learn the signs, know the life cycle of this annoying pest, and practice prevention so hopefully you can keep Japanese beetles away from your garden. Whether you’re a newbie gardener or someone with years of experience, Japanese beetles can affect you and your beautiful plants. Platt Hill Nursery has what you need to get your problem under control.
What Are Japanese Beetles?
Japanese beetles are an invasive species of insect first seen in the United States in 1916. Japanese beetles were first seen in New Jersey, but since that time, they have spread throughout the east and are steadily moving westward. Japanese beetles are currently found throughout the eastern United States in all states except in Florida.
In Illinois, Japanese beetles are found in all regions (northern, central and southern Illinois). They are one of the most destructive ornamental pests found in the state.
What Do Japanese Beetles Look Like?
Japanese beetles can be seen in their adult or larvae state. Knowing how to identify Japanese beetles in either state can help you determine when you have an infestation problem.
Adult
Adult Japanese beetles are approximately 1/3 to 1/2 of an inch long, with a metallic green head and copper-brown wing covers. The sides and abdomen of the Japanese beetle includes white patches of hair.
Larva
Japanese beetle larva are C-shaped whitish or cream-colored grubs with tan-colored heads. They have easy to see legs and can be anywhere from 1/8 of an inch to a full inch long. To determine whether a larva on your property is a Japanese beetle larva (versus other types of larva), look for the pattern of spines and hairs on the underside of their abdomen.
If you’re having a hard time determining whether your property has an infestation of Japanese beetles and larvae, take a picture of the insect of your concern and bring it with you to one of our stores in Carpentersville or Bloomingdale, IL.
Life Cycles of Japanese Beetles
Japanese beetle grubs spend their winter underground beneath grassy areas like lawns and pastures. When spring arrives, grubs move to the surface of the soil to finish feeding and turn into adult beetles.
If you’re in the southern part of the state, adult beetles may emerge in late June. In the Chicago area and central Illinois, adult beetles typically emerge in July. Adult beetles can fly up to several miles as they look for their meal.
They’re most active on sunny, warm afternoons in July and August. Plants that have been fed upon will emit an odor that attracts more beetles, which means that some plants sustain heavy damage throughout the growing season, while others remain relatively untouched.
Females produce a pheromone that is attractive to males. Once they mate, the females burrow underground about 2 to 4 inches to lay eggs. Females look for moist soil (like a well-watered yard) to lay their eggs, as dry soil conditions are not as conducive to larva survival.
Females can lay eggs several times in a season. It takes approximately 2 weeks for the eggs to hatch. Grubs eat the roots of grasses and begin to burrow deeper into the soil as the days grow colder. Once the soil drops below a certain temperature, grubs become inactive until the following spring.
Grubs grow throughout the summer and are nearly done growing by the time fall arrives. When the larvae rise to the top of the soil in spring, they leave a cavity behind. In this way, grubs do a great deal of damage to well-maintained lawns. When the larvae rise, they pupate and turn into adult beetles, and the cycle begins all over again.
Signs of Japanese Beetle Damage
Japanese beetles feed on flowers, trees, shrubs, fruits, vegetables, and field crops. Adults feed on as many as 350 species of fruits, vegetables, forage crops, weeds, field crops, and ornamental plants. Roses, grapes, basil, cherries, plums, raspberries, currants, elm trees, soybean, hollyhock, apple trees, corn silk, crabapples, and birch trees are all types of plants that attract Japanese beetles.
Adult Beetle Damage
Adult Japanese beetles feed on leaves, flowers, and fruits of many different plants. Adult beetles eat the leaf tissue between veins, leaving a lacy pattern of veins behind. On trees, this feeding begins high in the canopy and works its way down.
When the leaf is eaten, damaged leaves turn brown and often fall off. Most healthy mature plants can withstand the damage sustained during feedings and will not die, although they may be weakened and more susceptible to illness later. Young plants may be killed by persistent damage from adult Japanese beetles.
Most of the time, damage from beetles is considered cosmetic. However, the damage can be drastic. Ornamental plants damaged by adult Japanese beetles may no longer appear ornamental. For example, healthy flowering roses can survive Japanese beetle feedings, but the blossoms are ruined. It’s important to get rid of Japanese beetles whenever they first appear.
Vegetables, fruits, and vegetables may be damaged by some feeding and killed by persistent feeding. In addition, vegetables and fruits that are not killed by feeding may be less productive throughout the growing season.
Grub Beetle Damage
Damage from grubs can be devastating to a lawn. Grubs chew grass roots, often killing the grass. When the feeding is severe, large patches of dead grass will appear. In some cases, you may be able to roll the grass back like a carpet, because the grass roots no longer extend deep into the soil.
Less severe infestations may not kill grass. Some experts say that healthy turf grass can tolerate 10 grubs per square foot. However, there are many animals that will dig up grubs to eat, thus doing more damage. When the grubs emerge, they leave a cavity behind.
Effective Methods for Getting Rid of Japanese Beetles
There are many effective methods for eliminating Japanese beetles on your property. It’s important to start this process as soon as they appear. Inspect your grass for signs of infestation. Inspect your trees and plants as well. Keep in mind that some damage can lead to more damage. Once damage is extensive, it’s very difficult to control. If you can control the problem when it’s small, you may be able to stop more beetles from targeting your plants.
Japanese beetles feed for up to months, and you should continue to manage the problem until the insects begin to disappear in mid- to late-August. Managing beetles in large numbers can be very difficult.
Hand-Picking
Hand-picking Japanese beetles can be effective on small landscaping plants when only a few beetles are present. Soapy water is good for downing Japanese beetles. (By the way, soap is not intended to kill the beetles, it is used in the water to break the surface tension, so they will drown)
Simply shake or knock the beetles into a bucket of water. Children may enjoy this exercise, or you can do it yourself. The best time to do this is in the early morning when the beetles are still sluggish. Check plants daily. Watch for new signs of infestation and remain diligent throughout the growing season.
Using Japanese Beetle Traps
Japanese beetle traps use a pheromone to effectively draw beetles away from desirable plants, but it’s important to keep your traps far away from plants that are a preferred target. When kept too close to desirable plants, you may attract more beetles than you kill. These traps can collect a lot of beetles, but careful use is required to avoid damage to your nearby garden.
Adding Cover Barriers
Some cover barriers or even cheesecloth can help protect your plants like rose bushes. Avoid using covers at a time of year when pollination is taking place. Fruits, for example, need insect activity in order to produce their crop. For fruiting plants and plants that rely on pollination, handpicking beetles can be a more effective method of control.
Growing Japanese Beetle-Resistant Plants
Japanese beetles don’t eat everything. Some plants are simply not very attractive to Japanese beetles, including boxwood, confers, chrysanthemum, geraniums, forsythia, magnolias, common lilacs, rhododendron, oak, white poplar, and ginkgo trees.
If you’ve struggled with controlling Japanese beetles on your property, consider swapping out damaged plants for less desirable plants. You can get a range of Japanese beetle-resistant plants at Platt Hill Nursery.
Companion Planting
Sometimes just planting some undesirable plants near your existing target plants can help deter Japanese beetles in future growing seasons. Consider planting Japanese beetle-resistant plants near your more vulnerable plants in future seasons to improve the level of protection for your home.
Natural Remedies for Beetle Control
For homeowners who want natural remedies for Japanese beetles, there are several options.
Milky Spore
Milky spore disease kills Japanese beetle grubs but does not harm people. It’s a naturally occurring bacteria that can be applied to your soil any time that the ground isn’t frozen.
Applying Neem Oil
Neem oil is a natural insecticide that can be used to protect your plants from adult Japanese beetles. It’s important to follow all manufacturer recommendations when applying neem oil to your plants. Overuse of neem oil can burn plant leaves and flowers, especially when using it in combination with a sulfur spray. Careful use of this insecticide can be effective for smaller plants and smaller infestations.
Preventing Future Infestations
Although Japanese beetles can leave some gardeners feeling very helpless, there are many things you can do to prevent future infestations in your yard or garden.
Choose Plants Wisely
Choose plants that are less attractive targets. The pros at Platt Hill Nursery can help you find the shrubs, flowers, fruits, trees, and vegetables that are the least vulnerable to Japanese beetles.
Work With Your Neighbors
Infestations can affect neighbors. Work with your neighbors to devise a plan to make your properties less desirable to Japanese beetles. Help each other out by taking turns picking off beetles in the morning, or plan to landscape with Japanese beetle-resistant plants together.
Watch for Signs, Start Treatment Early
The best way to avoid a big infestation is to control a small one. Inspect your grass and plants for signs of infestation and start treatment as soon as you’ve noticed a problem.
Still Struggling with Beetles? Get Expert Help at Platt Hill Nursery!
Wondering how to get rid of Japanese beetles in your garden? Talk to the experts at Platt Hill Nursery. Contact us to get started with an effective defense against this irritating and damaging infestation.
