Japanese Beetles

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Here are tips on how to identify and get rid of Japanese beetles.

What are Japanese Beetles?

Japanese beetles are small pests that carry a big threat. They do not discriminate on what types of plants to feed on, in fact, they are classified as a pest to hundreds of different species. They are one of the most major insect pests in the Eastern and Midwestern US, causing monumental damage to crops each year. Native to Japan, they were first documented in the US in 1919, and have since spread across the country.

How to Identify Japanese Beetles

Japanese Beetles are ½ inch in length and metallic blue-green with tan wings, with small white hairs lining each side of the abdomen. They lay eggs in the soil during June, which develop into tiny white grubs. These grubs will remain under wraps for about 10 months and overwinter and grow in the soil. They emerge from the soil as adult beetles and begin feeding in June. They usually attack plants in groups, which is why damage is so severe. Although the lifecycle of the adult Japanese beetle is barely 40 days, it can cover a lot of ground. Look for leaves that are “skeletonized” (only have veins remaining). This is a tell-tale sign of Japanese Beetles.

How to get rid of Japanese Beetles

  • Try to select plants that Japanese Beetles will not be attracted to. See our list of Best and Worst Plants for Japanese Beetles.
  • In the grub stage of late spring and fall (beetles have two life cycles per season), spray the lawn with 2 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.
  • 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.
  • You can also purchase parasitic nematodes (most garden centers have them) and drench the soil around the area where you have the problem.
  • Neem oil and sprays containing potassium bicarbonate are somewhat effective.
  • Put down a dropcloth and, in the early morning when they're most active, shake them off and dump them into a bucket of soapy water. They will not survive.

 

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Comments

Can I use the dish soap mix

By Trisha Johnson on July 22

Can I use the dish soap mix in one gallon of water now or do I do that at the beginning of fall and will this help with the Japanese Beetle problem and this won't hurt my grass will it and I noticed this year we have so many holes in our yard is that probably from the Japanese Beetles there destroying everything my crape Myrtles my Roses my Hibiscus and my butterfly Bushes I've been hand picking them and putting them in soapy water there driving me crazy the worse we ever had.Need Help

You can use the dish soap mix

By Almanac Staff on July 23

You can use the dish soap mix now to cause the grubs to surface. Depending on where you live, some grubs will be in the soil in late July, but you might have more success in mid August into early fall, as more hatch; handpick those that surface, or leave them for the birds. You might test the soapy solution on a patch of lawn first--apply it either very early in the day so that it can dry on the grass before the hot sun hits it, or when the sun is setting; avoid applying when temperatures are over 80F. Some plants can be sensitive to soap sprays. Use the purest dishwashing liquid you can find, without additives if possible.

Japanese beetles lay eggs in the lawn in mid- to late summer.  Larvae emerge in late summer and fall and overwinter in the soil. Sources suggest that you do not water your lawn in midsummer--let it go dormant. And do not cut it very short. Japanese beetles prefer a moist lawn with longer grass blades in which to lay their eggs. Any larvae that hatch in late summer/fall may die because of lack of water. You might also try releasing beneficial nematodes (Heterorhabditis bacteriophora). Or, try walking across the lawn with spiked shoes (to kill the grubs just underneath).

Holes in the lawn might be from animals, such as skunks, who hunt at night to eat the grubs in the lawn. Birds might also spear the soil to get to the grubs.

I have perennial hibiscus and

By candim89 on July 20

I have perennial hibiscus and Japanese beetles are eating them up! What can I use on them to get rid of the beetles.

The Japanese Beetle does love

By Almanac Staff on July 22

The Japanese Beetle does love hibiscus. You need to put on some gloves and-pick the beetles in the early morning when they are sluggish and drop into a can filled with soapy water. The presence of beetles attracts more beetles.  You could use Reemay or other spun-bonded material to protect your plant for a while. Unfortunately, many organic sprays don't work and most of the chemical applications have high toxicity to bees which pollinate your plants. If all fails, consider choosing plants they do not like such as poppies, hosta and coreopsis. See more advice on this page.

The bettles I have in my yard

By Kwami on July 14

The bettles I have in my yard and garden are not green. They are closer to shinny brown/orange and start feeding at 10:00 pm sharp. They live right in the ball of the plants down in the soil. The only solution I know is to dig them up during the day and hand-kill them. I have manually killed about 500 in one day, easily. So which other Japanese beetle is the green ones?

We can try to help. Please

By Almanac Staff on July 15

We can try to help. Please tell us where you live? Which vegetables or plants are the beetles eating? What type of holes/evidence do they leave?

Is it o.k. to use the remedy

By Keith Etzel

Is it o.k. to use the remedy of two tablespoons of dishsoap in a gallon of water around fruit trees and blueberry bushes. I did not know if it would do anything to the trees.

Hi Keith, The dishsoap mixed

By Almanac Staff

Hi Keith,

The dishsoap mixed into a gallon of water is not going to harm your bushes or trees.

Is there something that can

By Timothy Hager

Is there something that can be added in the spring when tillilng soil that will help control the grubs that turn into the Beatle

What about fruit and

By linda m mann

What about fruit and vegetables in gardens? will this mixture help them or hurt them? I remember my dad used to use mixture to spray the lawn. I don't remember why. to kill bugs? thanks!!

Hi Timothy,   Milky spore

By Almanac Staff

Hi Timothy,

 

Milky spore powder and beneficial nematodes are a natural way of getting rid of grubs in the soil. Check your local garden center or do a quick search online to find out more about how to use them.

This year my peony brushes

By Carol Syracuse

This year my peony brushes grew usually long stems, them many of them twisted and curled around. On those stems the blossom grew but turned brown and of course never blossomed.

Do you have any ideas?

Please visit the peony page:

By Almanac Staff

Please visit the peony page: http://www.almanac.com/plant/peonies

I was told to get rid of

By Richard Williamson

I was told to get rid of Japanese Beetles to spray your plants with a mix of 2 tbls of vanilla extract and water.
They are on my rosé bushes and just showed up in the last 2 days.
Is this been tried by anyone?

We haven't heard this.

By Almanac Staff

We haven't heard this. However, you want want to cover your roses with cheesecloth or a fine netting during the peak of beetle activity.
If you find that natural solutions don't work, repeated chemical applications (malathion or sevin) are really the best control against Japanese beetles.

I saw a video where the

By Anne Peacock

I saw a video where the beetle ate a slug, so they aren't all bad.

you might change your mind

By arione

you might change your mind when you find all of your beautiful formerly healthy plants dying and stripped of leaves. Like mine. :(

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