How To Get Rid Of Japanese Beetles

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The beetles are coming! But their names aren't John, Paul, George or Ringo, and they don't bring stellar rock tunes or joy. Instead, they bring misery and death. If you haven't guessed it yet, we are talking about the dreaded summer pest-- Japanese Beetles. In this post, we'll talk about how to get rid of Japanese Beetles and give you all the juicy details that you aren't going to want to know. Fair warning: your skin is probably going to crawl.

To save those of you who do not want to read the entire post, we put our services/plan first on how to get rid of Japanese Beetles and how to prevent Japanese Beetles from ruining your yard. If you are more of a DIY'er, then scroll on by.

*** Although our method has been proven to be effective in preserving your investment we can not guarantee the complete prevention and extermination of all the Japanese Beetles in your area or neighborhood. 

Groundscapes' Plan On Preventing and Getting Rid of Japanese Beetles

Targeting Japanese Beetles before infestation:

  • Treat trees and shrubs through soil drench insecticide before Mother's Day (5/13)
  • Treatment starts at $55 and covers up to 5,000 sq ft of lawn or landscape.
  • $11.65 per additional 1,000 sq ft.

Targeting Japanese Beetles after emergence (between Mid May through July):

  • Foliar spray of insecticide during infestation. Usually needing to be done every other week for 1-1.5 months
  • Treatment starts at $55 and covers up to 3,000 sq ft (2 trees or 5-6 shrubs).
  • $11.65 per additional 1,000 sq ft.
  • Grub control treatment before July 4

Trees and shrubs most affected: Birches, Lindens, Maples, Elms, Cherries, Plums, and Peach trees, Roses and Buckthorn shrubs.

Target them during their mating cycle if you missed the proactive window before they defoliate your trees and shrubs.

Grub control is part of our standard 6 step fertilizer program. Give us a call at 402.397.5930 to talk about a plan.

Where do Japanese Beetles come from?

As the name suggests, the Japanese Beetle is native to Japan. Then they came over here in 1916. It's thought that the beetle larvae entered the United States in a shipment of iris bulbs prior to 1912, from there they essentially took over various parts of the United States.
Where do Japanese Beetles live?

Japanese Beetles originally thrived in the Eastern United States where there are large areas of turf and pasture grass for developing grubs, hundreds of species of plants they could feed on, and no effective natural enemies. They have steadily expanded the geographic range and are north to Ontario and Minnesota, west to Nebraska, Iowa, Missouri and Arkansas, and south to Georgia and Alabama. In a nutshell, they like it hot and grassy, and they love the Omaha Metro area.

What is the lifespan of a Japanese Beetle?  

Mostly, the Japanese Beetle completes its life-cycle in one year. Adults emerge anywhere from mid-May to June.

"Males emerge a few days earlier than females, but eventually the population maintains a sex ratio of 1:1 Mating begins soon after emergence as virgin females releases powerful sex pheromones that immediately attract a large number of males. In an attempt to mate, the attracted males form a congregation around the unmated female, forming clusters referred to as beetle "balls" but mating rarely occurs under such intense competition."

Fortunately, the beetle has a short lifespan ranging from 17 days to 105 days, so by the end of July, the pests start becoming less of a nuisance.

What Do Japanese Beetles Eat?

Japanese Beetles feed on about 300 species of plants, devouring leaves, flowers, and overripe fruit. They usually feed in groups, starting at the top of a plant and work downward. The beetles are most active on warm, sunny days, and prefer plants that are in direct sunlight.

In Nebraska, the most commonly affected trees and shrubs are Birches, Lindens, Maples, Elms, Cherries, Plums, and Peach trees, Roses and Buckthorn shrubs.

How To Prevent Japanese Beetles

Treat your plants and trees before the beetles emerge! A general rule of thumb is to treat before Mother's Day. Treat trees and shrubs through soil drench insecticide. Target them during their mating cycle if you missed the proactive window before they defoliate your trees and shrubs.

Here are some other tips from the Farmer's Almanac.

For general preventive maintenance, experts recommend keeping your landscape healthy.

Remove diseased and poorly nourished trees as well as any prematurely ripening or diseased fruits, which can attract Japanese beetles. Try these tips:

  • Select plants that Japanese beetles will not be attracted to. See our list of the Best and Worst Plants for Japanese Beetles. Dispersing their favorite plants throughout the landscape, rather than grouping them together, can also help.
  • In the grub stage of late spring and fall (beetles have two life cycles per season), spray the lawn with two tablespoons of liquid dishwashing soap diluted in 1 gallon of water per 1,000 square feet. The grubs will surface, and the birds will love you. Spray once each week until no more grubs surface.
  • You can introduce the fungal disease milky spore into your lawn to control the Japanese beetle larvae population. The larvae ingest the spores as they feed in the soil. The spore count must be up for two to three years for this method to be effective. Fortunately, the spores remain viable in the soil for years. This is an expensive treatment, as all the soil within five-eights of a mile needs to be treated for good control.
  • You can also drench sod with parasitic nematodes to control the larvae. The nematodes must be applied when the grubs are small and if the lawn is irrigated before and after application. Preparations containing the Heterorhabditis species seem to be most effective.
  • Companion planting can be a useful strategy in preventing pests. Try planting garlic, rue, or tansy near your affected plants to deter Japanese beetles.
  • You can also attract native species of parasitic wasps (Tiphia vernalis or T. popilliavora) and flies to your garden, as they are predators of the beetles and can be beneficial insects. They will probably attack the larvae, but they are not very effective in reducing the overall beetle population.

Do Japanese Beetle Traps Work?

Short answer: not well. They attract more beetles and do not suppress adult beetles, so we do not believe traps to be an effective way to protect your yard.

How To Get Rid Of Japanese Beetles

Good horticultural practices and a yard maintenance plan will dramatically impact the effect that the Japanese beetles will have on your yard. Specifically, watering and fertilizing will reduce the damage caused by these beetles.

Foliar spray of insecticide during infestation every other week for one to two months is the best way to get rid of the Japanese Beetles and protect your yard.

Here are some other tips from the Farmer's Almanac.

  • Row Covers: Protect your plants from Japanese beetles with row covers during the 6- to 8-week feeding period.
  • Hand Pick: Unfortunately, the most effective way of getting rid of Japanese beetles is to hand pick them. It's time-consuming, but it works, especially if you are diligent. When you pick them off, put them in a solution of 1 tablespoon of liquid dishwashing detergent and water, which will cause them to drown.
  • Neem Oil: Neem oil and sprays containing potassium bicarbonate are somewhat effective, especially on roses. The adults ingest a chemical in the neem oil and pass it on in their eggs, and the resulting larvae die before they become adults. Neem can be harmful to fish and should be reapplied after rainstorms.
  • Use a Dropcloth: Put down a drop cloth and, in the early morning when they're most active, shake them off and dump them into a bucket of soapy water.
  • Insecticides: If you wish to spray or dust with insecticides, speak to your local cooperative extension or garden center about approved insecticides in your area. Or, try this safe homemade solution: Mix 1 teaspoon of liquid dishwashing detergent with 1 cup of vegetable oil and shake well; then add it to 1 quart of water. Add 1 cup of rubbing alcohol and shake vigorously to emulsify. Pour this mixture into a spray bottle and use it at ten-day intervals on pests. Homemade sprays can run more of a risk of damaging plant leaves, so be careful. Apply sprays in the morning, never in full sun or at temperatures above 90ºF. If your plants start to wilt, rinse the leaves immediately with clean water.
  • Traps: Japanese beetle traps can be helpful in controlling large numbers of beetles, but they also might attract beetles from beyond your yard. Eugenol and geraniol, aromatic chemicals extracted from plants, are attractive to adult Japanese beetles as well as to other insects. Unfortunately, the traps do not effectively suppress adults and might even result in a higher localized population. If you want to try them, be sure to place traps far away from plants so that the beetles do not land on your favored plants on their way to the traps.
  • Fruit Cocktail: You can buy Japanese beetle traps of all sorts, but most are no more effective than a can of fruit cocktail. Open the can and let it sit in the sun for a week to ferment. Then place it on top of bricks or wood blocks in a light-colored pail, and fill the pail with water to just below the top of the can. Place the pail about 25 feet from the plants you want to protect. The beetles will head for the sweet bait, fall into the water, and drown. If rain dilutes the bait, start over.
  • Geraniums: Japanese beetles are attracted to geraniums. They eat the blossoms, promptly get dizzy, fall down, and permit you to dispose of them conveniently with a dustpan and brush. Plant geraniums close to more valuable plants which you wish to save from the ravages of Japanese beetles.
  • Japanese Beetles on Roses: Note that insecticides will not fully protect roses, which unfold too fast and are especially attractive to beetles. When beetles are most abundant on roses, nip the buds and spray the bushes to protect the leaves. When the beetles become scarce, let the bushes bloom again. Timeliness and thoroughness of application are very important. Begin treatment as soon as beetles appear, before damage is done.

There you have it, that is how to get rid of Japanese Beetles! Did your skin crawl? It made ours crawl just writing this.