The Secret Weapon You Need To Get Rid Of Japanese Beetles For Good

Japanese beetles are an invasive species with no natural enemies in the U.S. They can destroy a garden in a matter of days with their voracious appetites and quick mating process. Adults will ravage the leaves of your plants, while their grubs will destroy root systems. Specialized Japanese beetle traps are sold commercially, but they're often large and unsightly. A better solution is to spray the beetles with an easy homemade spray of soapy water. As unlikely as it sounds, simple soapy water is lethal to these invasive pests and life-saving to roses, berry bushes, and other plants.

The tell-tale sign of a Japanese beetle infestation is lacy leaves. When the leaves of your plants have been eaten away in the centers of their sections with the veins left intact, it creates the impression that your leaves are made of green lace or that they are just the skeletons of the plant. Of course, another sure sign is if you see even one Japanese beetle in your yard, as they travel in droves. Finding one means dozens more are nearby, so you need to act quickly to get rid of them.

The best soap and water spray to kill Japanese beetles

The best soap to use to keep Japanese beetles out of your garden is a standard dish soap like Dawn or Palmolive, made to dissolve grease off of dishes. Mix 1 teaspoon of dish soap into each quart of water you prepare, stirring well. Once the mixture is created, use a funnel to fill a spray bottle with it. You can shake the bottle to make sure the solution is thoroughly mixed, but let it settle afterwards so the bubbles don't hinder the spray mechanism. Alternatively, you could fill a hose attachment with the soap as well.

Go out in the morning when the beetles are sluggish and spray your solution over them. The grease-fighting capabilities of the dish soap will dissolve the waxy coating of the beetles, and their cells will break down, causing the invading insects to suffocate. Plan on applying your spray every morning or every other morning until you no longer see Japanese beetle activity. This will ensure that you've killed off not only the established adults but also the newly developed ones who haven't started mating yet, effectively eliminating the entire colony.

An alternative to spraying

Another way to kill the Japanese beetles is to take your bucket of soapy water out into the garden with you. Wearing your gardening gloves, shake or brush the Japanese beetles off your plants and directly into the bucket of water, where they will drown. Once again, it's best to repeat this process every day or so in order to confirm you've eliminated all the Japanese beetle activity in your yard and no new grubs will be taking over. 

You can also leave bottles of the soapy water mixture out around your backyard space, allowing the beetles to fall in whenever they come to investigate. However, this latter method provides less of a guarantee of success, so only resort to it as an additional failsafe or in the case that you can't do daily spraying or shaking maintenance. Whichever method you choose, this soapy water hack is a great way to completely rid yourself of a Japanese beetle infestation without contaminating your space with harmful and toxic insecticides.