Sasha CampbellJapanese beetles (Popillia japonica) may look shiny and harmless. However, they can quickly become one of the most destructive pests in your garden.
These pests feed on the leaves, flowers, and fruit of various plants [1]. While chemical insecticides can offer quick results, many gardeners prefer natural alternatives.
Luckily, a few homemade traps and tricks can help reduce their populations. These DIY methods are also easy to try.
First, it helps to know how to identify Japanese beetles and recognize the signs of an infestation.
Identification
Adult Japanese beetles are about ½ inch long. They have metallic green bodies and copper-colored wing covers [2].
Small white tufts of hair are visible along the sides of their abdomen. They often gather in groups while feeding.
Signs of an Infestation
Common signs of Japanese beetle damage include skeletonized leaves, chewed flowers, and damaged fruit. There may also be large groups of beetles feeding together.
Leaves often appear lacy because the beetles eat the tissue between the veins.
Plants Japanese Beetles Commonly Attack
Japanese beetles feed on more than 300 plant species [3].
Some of their favorite plants are roses, grapes, raspberries, and blackberries. They also enjoy hibiscus, hollyhocks, apple trees, cherry trees, and beans.
Regularly inspecting these plants can help you spot infestations early.
Best Homemade Traps for Japanese Beetles
Below are some of the best homemade traps and natural remedies for controlling Japanese beetles.
1. The Bucket Trap
One of the easiest ways to catch Japanese beetles is to use a 5-gallon bucket trap. All you need is a half-bucket of water and some liquid dish soap. Stir it up a bit.
Next, position the bucket of soapy water under a branch or plant where you’ve spotted beetles gathering.
Japanese beetles have an odd defense mechanism. They often respond to disturbances by dropping from plants and playing dead. This behavior makes them easier to collect in soapy water.
Take advantage of this by giving the branch a good shake. The beetles will fall straight into the soapy water and meet their end.
The soap breaks the water’s surface tension, causing the beetles to sink and die.
2. Trap Crops
Trap crops are sacrificial plants grown to attract pests away from your main crops.
For Japanese beetles, this technique can be highly effective. They are especially fond of certain plants, such as roses, grapes, raspberries, hollyhocks, evening primrose, and corn silk.
Plant these trap crops on the outer edges of your garden or in a separate area. They will lure the beetles away from your vegetables and flowers.
Once they gather on the trap crops, you can more easily target them with a natural insecticide or hand-pick them off.
3. Food-Bait Trap
A more advanced yet simple homemade trap utilizes fruity scents to lure beetles to their demise.
You’ll need a bucket of water and one cup of fruit, such as raspberries or grapes. You’ll also need a cup of apple cider vinegar.
Throw everything into the bucket of water. The fruity scent may attract Japanese beetles searching for food.
While this homemade trap is not as effective as commercial pheromone traps, it can help capture some beetles. But be mindful not to place this trap too close to your garden. The bait may draw other insects into the area.
4. Drop Cloth
Another organic way to control beetle populations is by using drop cloths.
Japanese beetles are sluggish in the early morning. Therefore, take advantage of this by placing a piece of cloth on the ground under your plants.
Next, shake the branches gently to dislodge the bugs. Finally, carefully remove the cloth and shake it out into a container of soapy water.
This method allows you to catch large numbers of beetles at once. The drop cloth is also reusable and easy to set up.
5. Diatomaceous Earth
Diatomaceous earth is deadly to many insects, including Japanese beetles. It damages the insects’ protective outer coating, causing them to lose moisture and die.
Lightly sprinkle food-grade diatomaceous earth on the leaves and around the affected plants in the soil. However, you will have to reapply it after it rains. Moisture reduces its effectiveness.
This method is most effective in dry weather conditions. It can also help kill beetles that come into contact with it while feeding on plants.
Other Natural Remedies to Repel Japanese Beetles
In addition to traps, you can also use natural deterrents to make your garden less attractive to Japanese beetles.
Neem Oil
Neem oil is a natural pesticide that can help deter Japanese beetles and reduce feeding damage [4]. It can also kill other insects that you do not want on your plants.
You can buy a neem oil-based product.
You can also create a DIY spray solution. Just mix two tablespoons of neem oil with a gallon of water. Add a tablespoon of liquid soap as well.
Spray your neem oil solution directly onto the affected plants.
Garlic or Pepper Spray
Beetles dislike strong smells, such as those of garlic or spicy peppers.
Therefore, a homemade spray made from crushed garlic cloves or hot peppers may help deter Japanese beetles. Spray it on your plants.
Row Covers
You can also use lightweight garden fabric to cover your plants. This will physically block beetles from accessing plants.
However, be sure to remove the covers during flowering if you rely on pollinators for successful fruit production.
Beneficial Nematodes
Applying beneficial nematodes to your soil can also reduce beetle larvae, known as grubs, before they emerge as adults. These organisms feed on the larvae, keeping their numbers down.
Milky Spore
Another long-term solution is milky spore, a naturally occurring bacterium that infects Japanese beetle grubs in the soil. However, this remedy does not harm beneficial insects.
Companion Plants
Some gardeners report seeing fewer Japanese beetles near strongly scented plants. Examples include garlic, catnip, chives, tansy, and chrysanthemums.
While not foolproof, these plants may help make the area less attractive to beetles.
Hand-Picking
Hand-picking is one of the simplest ways to reduce Japanese beetle numbers.
Early in the morning, when the beetles are less active, knock them into a bucket of soapy water. Repeating this process regularly can help limit feeding damage and reduce future populations.
Prevention Tips
While it is difficult to eliminate Japanese beetles entirely, a few preventive measures can reduce future problems:
- Remove beetles as soon as they appear.
- Keep weeds under control.
- Use row covers when practical.
- Apply beneficial nematodes to reduce grub populations.
- Inspect susceptible plants regularly during summer.
Takeaway
Japanese beetles can be stubborn garden pests. However, with a bit of creativity and effort, you can cut down their numbers using homemade traps and natural solutions.
You can use simple methods, such as a bucket of soapy water or trap crops, to manage these pests. These methods are eco-friendly and serve as good alternatives to chemical pesticides.
To get the best results, combine these techniques. Then, keep an eye on your garden during peak beetle season.
However, if using pheromone traps, place them well away from valuable plants. Otherwise, they may attract additional beetles into your garden.
Add comment