Sasha CampbellJapanese beetles are destructive pests that feed on many plants. They often gather in groups, causing serious damage to leaves, flowers, and fruits.
Adult Japanese beetles are often most active from late June through August in many areas [1]. During this time, they feed on plant foliage and fruits, while their grubs mainly feed on grass roots.
Therefore, early control is important to prevent significant damage.
How to Get Rid of Japanese Beetles Naturally
Below, we have gathered some of the best home remedies and organic control methods to help keep these destructive plant pests at bay.
1. Pick Them Off
Hand-picking Japanese beetles is one of the simplest and most effective ways to manage small infestations. This method allows for immediate action and reduces damage to plants.
Pick them off in the morning or evening when they are cool and sluggish. Drop them into a container of soapy water.
2. Drop Cloth
A drop cloth is handy, especially in the early morning when the beetles are sluggish.
Spread a light-colored cloth or sheet under the affected plant. Gently shake the plant so the beetles fall onto the cloth.
Pick them up and drop them into soapy water.
3. Vacuum Them
Check your plants often and vacuum the beetles whenever you spot them.
Use a small handheld vacuum to remove beetles from plants. Empty the vacuum outside into a container of soapy water.
4. Row Covers
Row covers help prevent insect pests from gaining access to your crops.
Place the row covers over your crops. Use plastic hoops or wooden frames to support them. Secure the edges so Japanese beetles cannot get underneath.
Remove the covers when plants are flowering and need bees or other pollinators.
5. Neem Oil
Mix neem oil with water according to the product label. Some neem oils need a small amount of mild soap to help the oil mix with water.
Shake well, then spray your plants. This spray may help deter feeding and reduce Japanese beetle damage when used according to the label.
Some products containing azadirachtin may also help control Japanese beetles and their grubs. Always follow the product label.
6. Kaolin Clay
Kaolin clay creates a thin barrier on plant leaves. This barrier can make the leaves less attractive to Japanese beetles.
Mix and apply kaolin clay products according to the package instructions. Reapply as directed, especially after heavy rain.
7. Bt Galleriae
Bacillus thuringiensis galleriae, or Bt galleriae, is a bacterial insecticide that can help control Japanese beetle adults [2].
After consuming the product, susceptible Japanese beetles may stop feeding and eventually die.
8. Beneficial Nematodes
Beneficial nematodes, such as some Steinernema and Heterorhabditis species, can attack Japanese beetle grubs [3].
They enter the grubs and release bacteria that kill them. Their effectiveness can vary.
Apply the nematodes according to the product instructions. Water the soil before and after application, and keep the soil moist as directed.
Avoid applying them during hot, sunny conditions.
9. Pyrethrin
Pyrethrin insecticides can kill Japanese beetles when the spray hits them directly.
However, pyrethrins can also harm bees and other beneficial insects. Avoid spraying them when pollinators are visiting flowers.
10. Beauveria bassiana
Beauveria bassiana is a naturally occurring fungus that leads to white muscardine disease in many insects [4].
When beetles come into contact with the fungus, they may become infected. Infected beetles can develop a white fungal coating and die over time.
Follow the product label for application instructions.
11. Keep Plants Healthy
Healthy plants can often handle some insect damage better than weak or stressed plants. Give your plants the water, sunlight, and nutrients they need.
Do not use more fertilizer than the product label recommends. Too much fertilizer can harm plants and cause unwanted growth.
Check your plants often during Japanese beetle season. Finding and removing the first beetles can help prevent the problem from becoming worse.
12. Let the Lawn Go Dormant When Possible
If your lawn can safely go dormant, avoid unnecessary watering during the main egg-laying period [5].
Japanese beetle eggs and young grubs need moist soil to survive, so dry soil can reduce their chances of survival.
However, local weather and soil conditions affect how well this works. Do not let plants or lawns dry out if doing so could cause serious damage.
13. Chickens and Birds
Chickens, wild birds, and other animals may eat Japanese beetles and their grubs. However, predators alone may not control a large infestation.
14. Parasitic Wasps
Some parasitic wasps attack Japanese beetle grubs. The spring Tiphia wasp is one example.
These wasps may help reduce grub populations, but they may not provide enough control by themselves.
15. Geraniums
Japanese beetles may feed on geranium blossoms. However, research has shown that Japanese beetles may become temporarily paralyzed after feeding on certain geranium species [6].
In that state, they are left vulnerable to predators. This effect is not a reliable way to control a large Japanese beetle infestation.
16. Milky Spore
Milky spore is a natural bacterium that can infect Japanese beetle grubs.
It may take several years to become established in the soil. However, research on commercial milky spore products has shown mixed results.
Do not expect quick control.
17. Repellent Plants
Some gardeners plant strongly scented herbs and flowers near their gardens. However, there is limited scientific evidence that these plants can protect a garden from a serious Japanese beetle infestation.
These plants include marigolds, nasturtiums, chives, tansy, catnip, and rue. You can grow these plants for their flowers, herbs, or other benefits, but do not rely on them alone to control Japanese beetles.
18. Garlic Spray
Some gardeners use garlic sprays as a natural insect repellent. However, homemade garlic sprays may not provide reliable control of Japanese beetles.
If you want to try this method, make a homemade garlic spray.
Purée 5 cloves in 1 cup of water. Next, add a teaspoon of liquid soap to the solution. Finally, strain and spray your plants.
Test homemade sprays on a small part of the plant first. Some sprays can damage leaves.
19. Remove Overripe and Fallen Fruit
Japanese beetles feed on many types of fruit. Remove overripe fruit from plants and pick up fallen fruit from the ground.
This will not get rid of a large infestation. However, it can remove an extra food source from your garden.
See also: How to Control Black Beetles Naturally.
Takeaway
Japanese beetles can cause serious damage when large numbers gather on plants. Therefore, check your plants often during Japanese beetle season.
Removing beetles early can help reduce plant damage before the infestation becomes severe.
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