People ask me all the time how they can get rid of Japanese beetles (Popillia japonica Newman).
It’s not easy but it can be done as long as you are persistent.
One beetle by itself won’t do a lot of damage but once they start to feed on your plant they send out a signal to other beetles that there is food available. The next thing you know you have an infestation going on.
They are common garden pests that will devour your plants within a day if they are not controlled.
I have seen them on a few of my garden plants that I have around my landscape.
They are coppery brown to greenish coloured bugs about half an inch long and they can fly. They aren’t very good fliers however and usually miss their target on the first try.
They are very transient in that they keep moving until they find food and then they stay there until the food is gone then move on to the next food source.
The adult beetles feed:
Their grubs feed on the roots of ornamental trees, shrubs, garden plants, and grasses and live less than a foot underground.
Killing Japanese beetles can be done several ways but they are a bug that you will have to watch for from June until fall when it starts to get cooler outside.
Here are some tried and proven ways to kill Japanese beetles and their grubs.
The best and most effective way to kill Japanese beetles is to pick them off with your hands or shake the branches of your plants and put the beetles in a solution of 1 tbsp dish soap and a gallon of water. The dish soap makes it impossible for them to get out of the water and therefore they will drown in the water solution.
I have done this many times and it does work.
You can also vacuum them off with a hand held vacuum and dump the bag or canister into the water solution. This DOES work but, yes, it is time consuming.
There are sprays you can use to control the beetles. The most effective ones contain Neem oil or some type of insect killing soap.
The Neem oil will stop the beetles from feeding as it has a toxic effect when sprayed on the beetles.
I haven't tried a Japanese beetle traps but they are another way to get rid of Japanese beetles. Keep in mind that they do attract beetles from other yards as well, so you could end up with a lot of Japanese beetles in your yard.
If you use the traps, keep them at the back of your yard, far away from your favourite plants.
Because they are terrible flyers and they usually miss their target they could land on other plants that are around the trap.
I’ve had the question asked “Does anything eat Japanese beetles”. The answer is yes.
Parasitic wasps are beneficial insects that hunt the Japanese beetle. They lay their eggs on the beetles and when the eggs hatch the larva fed on the Japanese beetles which will help control their population.
The Tachinid fly is similar to the parasitic wasps in that it also lays its eggs on the Japanese beetle. The eggs hatch within 24 hours and the larva start eating the beetle.
Another great beneficial insect is Heterorhabditis Bacteriophora Nematodes, also known as beneficial Nematodes. They burrow into the soil about 7” looking for their prey. Besides Japanese beetles, they also prey on ants, fleas, moths, flies, weevils and other common garden pests.
There are places online that you can buy beneficial insects. The Ontario Ministry of Agriculture, Food and Rural affairs have a good list of places to buy beneficial insects to help get rid of Japanese beetles.
Besides the insects listed above Japanese beetles have a few predators that will feed on them also:
Other predators are:
Lawn grubs are the larva from Japanese beetles. They are small white caterpillar-looking bugs that live under the grass. They eat the roots of grass and leave behind brown dead spot in your lawn.
They will overwinter under ground and as the weather warms they will slowly leave the soil to feed on plants as they become adults.
If you want to get rid of Japanese Beetle Grubs spray your yard with 2 tbsp of dish soap mixed with 1 gallon of water. This will cover an area of about 1000 square feet.
When the mixture reaches the grubs, they rise out of the soil and birds will eat them.
According to the Old Farmer’s Almanac
these organic sprays do work.
Nematode (available at Canadian Tire and Home Depot) will kill the grubs and any soil dwelling insects. When the grubs are still small, soak your lawn with water, apply Nematode as directed and then soak your lawn again.
Here is a video from Canadian Tire that shows you how to apply nematodes to your lawn.
Milky Spore is reported to work effectively and is a safe and organic way to control Japanese beetle grubs or larvae. It’s a natural occurring bacteria that is spread over your lawn and will kill the grubs before they reach adulthood.
The grubs eat the spores, which will reproduce while inside the grubs and kill them within 7-21 days. Milky Spore is available through Amazon
There are insecticides that will work to get rid of Japanese beetles but they are poisonous to honey bees and other beneficial insects so please be careful when using them.
Weeds and plants that attract Japanese Beetles.
If you have any of these plants try planting garlic, rue herb or tansy (an invasive herb) around them to get rid of Japanese beetles.
Plants for Japanese Beetle Control
Japanese beetles tend to stay away from these plants so they are good plants to have in your yard.
If you know of any other ways that you have tried and have worked to get rid of Japanese beetles contact us and we can add it to this page.