Among the pests that attack and feed on plants are Japanese beetles. Damage can be extensive as they eat in groups, feeding on flowers, vegetable crops, and fruit trees.
Adult Japanese beetles are most active from late June through August . During this time, they (see picture above) feed on the foliage of plants while the grubs attack the roots. Therefore, it is vital that you get rid of them quickly.
Below we’ve gathered some of the bestand organic control methods to keep away these destructive insects.
Here’s how to get rid of Japanese beetles naturally.
1. Pick Them Off
This method is time-consuming and tedious, but it’s the most productive control method for Japanese beetles. Pick them off and squish them or throw them into a container with soap and water.
2. Neem Oil
Extracted from the seeds of the neem tree, neem oil is a common organic pesticide used by backyard farmers worldwide.
To use neem oil for Japanese beetles, combine 2 tablespoons of neem oil and a teaspoon of liquid soap with a gallon of water.
Shake well and use it to spray your plants. This homemade solution will kill the beetles before they reach the adult stage.
Use it to keep Japanese beetles off your roses, hibiscus, grape vines, and vegetable plants. Spray every 7 days while the pests are active.
3. Row Covers
Row covers block harmful pests from getting to your crops.
Following the installation manual, fix row covers over the crops using plastic hoops or wooden frames for support. Next, secure the edges with staples to keep the critters off your plants.
4. Beneficial Nematodes
Beneficial nematodes are live microscopic organisms that are natural predators for Japanese beetle grubs. They get into the body openings of these pests and find their way to the bloodstream, killing them within two to three days.
The nematodes can be dispersed into the soil using a watering can, and the best time to apply is in the evening as they do not like direct light.
Also, moist conditions provide a conducive environment for beneficial nematodes to thrive. Therefore, it’s advisable to sprinkle enough water into the garden before and after the application.
5. Diatomaceous Earth
One of the best natural Japanese beetle killers, diatomaceous earth causes the beetles to die from dehydration. It does so by cutting through their protective outer shell, destroying their exoskeleton.
To use, sprinkle it on the leaves, stems, vines, roots of the plants, and on the garden soil around to deter them. Besides, you can use it inside the house, sprinkled directly on the bugs when they are visible.
Alternatively, make a DIY Japanese beetle spray by combining 1 part DE with 4 parts water. Add to a spray bottle and use the solution to spray the larvae and adults. Once it dries out it will kill them.
6. Soap and Water
Spraying your plants and lawn with a little organic soap and water is an excellent way to get rid of them organically. All you need for this recipe is four to five tablespoons of organic liquid soap and a gallon of water.
Spray the beetles directly with the soapy water or pick them off and drop them into a bucket of the solution. Soapy water will kill Japanese beetles by way of suffocation. This home remedy also works on Japanese beetle larvae.
7. Repellent Plants
While planting crops that are susceptible to beetle attack, consider planting together with plants that keep the pests away.
Plants that repel Japanese beetles include marigolds, nasturtium, chives, tansy, catnip, and rue.
8. Fowls and Birds
Poultry and birds are good predators to adults as well as the grubs.
Attract these animals to your garden or yard by providing them with food and water. Some birds eat the adult beetles while others dig up the grubs.
9. Vacuum Them
Every day, dedicate some time to vacuum the infested plants. Afterward, put the vacuum’s content in a container full of soapy water to kill the critters.
10. Cedar Oil
An excellent natural Japanese beetle repellent is cedar oil. It has a long-lasting smell that keeps them away.
Combine four tablespoons of cedar oil with a gallon of water. When sprayed on plants, its strong scent will keep the pests off.
Japanese bugs are attracted to geraniums and will munch on them. However, after feeding on the blossoms, they will get dizzy and lay on their backs.
In that state, they are left vulnerable to predators. You can also pick them off and drop them in soapy water to kill them.
12. Kaolin Clay
Kaolin clay helps keep off beetles eating leaves by creating an irritating whitish film on leaves and fruits.
Our recommended brand is Surround WP.
To make a natural spray for Japanese beetles using Kaolin clay, mix 3 cups with a gallon of water and coat your plants. Moreover, you can use this spray up until the harvesting day.
13. Milky Spore
Milky Spore contains spores of the naturally occurring bacterium Paenibacillus popilliae, which destroys the grub stage of the beetle.
When dispersed into the soil, the grubs must ingest the spores when feeding. When this happens, the spores reproduce inside the pests, killing them within 7-21 days.
Pyrethrin is an organic insecticide that kills Japanese beetles and other insects. Aiming at their nervous systems, once the pests come across it, they become paralyzed and eventually die.
However, avoid using it when beneficial insects and pollinators are around.
15. Beauveria bassiana
Once the beetles come into contact with the fungi, they get infected. This is when you’ll notice a whitish coating on them. They’ll eventually die within one to two weeks.
Sold at most well-established gardening centers, these traps are baited with lures to produce a scent that’s inviting to the adult bugs.
Once they are trapped, you can get rid of the critters. However, the scent may attract other critters that are not within your garden, and not all of them are likely to be captured.
Alternatively, make a homemade Japanese beetle trap by adding one cup of sugar, one cup vinegar, and a crushed ripe banana to a bucket of water. The fermenting scent will lure them in, after which they’ll fall in and drown.
17. Avoid Watering Grass
One of the most effective Japanese beetle control home remedies is to avoid excess watering during their season. They are most active from late June through August or September.
During this period, watering the grass is discouraged as moist, grassy areas provide a conducive environment for the females to lay their eggs.
18. Bacillus thuringiensis (B.t.)
Another fantastic organic treatment for Japanese beetle grubs is Bacillus thuringiensis.
Bt is a soil-dwelling bacterium that produces proteins that are toxic to the grubs. After consuming it, the pests will die.
19. Drop Cloth
A drop cloth is handy for this purpose, especially in the early morning hours when the beetles are very active.
Spread the cloth in the garden. Once the critters are on it, shake them off in a container full of soap and water.
20. Garlic Spray
A mixture of garlic, liquid soap, and water sprayed directly on the affected plants is great for preventing the critters from coming around.
To make a homemade Japanese beetle spray using garlic, puree 5 cloves in a cup of water. Next, add a teaspoon of little liquid soap to the mix, then strain and spray your plants.
Use the measurement as a guide for larger concoctions. The scent of garlic is unappealing to the critters. As a result, they will not come near once you apply garlic spray to your plants.
21. Parasitic Wasps
Attracting parasitic wasps in your garden can be an effective way of controlling the larvae. However, parasitic wasps are not that effective when it comes to handling high numbers of pests.
Japanese beetles mainly go after plants such as grapes, roses, hibiscus, dahlias, petunias, zinnias, apple trees, basil, birch, berries, shrubs, and corn. Therefore, be on the lookout and take action before an infestation begins.