How to get rid of Japanese Beetles

Do you have iridescent green beetles feasting on your garden? You've got Japanese beetles! This pest is sweeping neighbourhoods, devastating gardens, shrubs, and trees without mercy. Below you'll find some of our tips on how to identify and get rid of Japanese beetles.

What are Japanese Beetles?

The Japanese beetle (Popillia japonica) is a species of scarab beetle originating from Japan, making their first appearance in North America a century ago. 

Japanese beetles are easily identifiable as they have bright metallic green heads with copper coloured bodies. Another dead giveaway is the skeletonized leaves they leave behind. They do not discriminate when it comes to what types of plants they feed on, though they do have favorites such as climbing vines, hibiscus and roses.

When do I need to worry about Japanese Beetles?

Since chemical pesticides were taken off the market approximately 10 years ago, these insects have been coming back year after year. The life cycle of these insects has three larval stages. Once they have reached maturity, the larvae pupate, and after a diapause of about two weeks in late June, early July, the adult beetles emerge from the ground. These insects will damage different parts of your property at different times in their life cycle. It is ideal to target them before they emerge in adulthood when it is much more difficult to get rid of them.

How can I get rid of them?

This insect is difficult to control for a couple of reasons, first is the lack of natural predators here which has made them a major pest. Secondly, since chemical pesticides were taken off the market, there is a lack of 'quick fixes'. That said there are still some things that gardeners can do to fight these nasty bugs.

Nematodes

In our opinion, applying nematodes in the spring and fall when they live in your soil as grubs can kill the problem before they emerge as adult beetles. This is an effective and organic method of controlling the population of Japanese beetles. 

There are many varieties of nematodes available in the market, so be sure to buy the heterorhabditis bacteriophora nematode, as this is the best for Japanese beetle control. Nematodes can be used to control a wide variety of soil-living insects and aerial insects in their soil-living stage. 

Japanese Beetle Traps

This is the most common method used. These devices release both a sex pheromone and a floral scent, which are very effective in attracting adult beetles. They fly to the trap, where they crawl or fall into the bag and cannot get out. You simply have to empty out the bag and re-attach it, and the process starts all over again.

The problem is, traps attract about four times as many beetles as they normally would in your yard, and only 50% to 75% of them will actually end up in the bag. The others bounce back and head happily to your garden, where they vigorously munch on your plants and lay plenty of eggs for next year's beetles. From mid-June to the end of July, if you and your neighbours hang traps throughout the infested area, you may be able to prevent the bugs from migrating from one yard to another. It is very important to note that these traps should be placed as far away from their favorite plants as possible, near the edge of your property or you will possibly make the situation worse. In addition, the trap bag should be emptied every day, ideally even twice a day so that the stench of the dead beetles does not drive others away. Since cleaning traps is a pretty disgusting task due to the bad smell, if not everyone does it daily, this is far from a perfect solution.

Row Covers

Some people use floating row covers which are basically white garden fabrics that can be draped directly over the plants and secured around the perimeter. Unfortunately, it is not aesthetically pleasing. Click here to see a top rated row cover we found online.

Shop-Vac or Hand-picking

Some people roll up their sleeves and pick them up by hand and throw them in a soapy water solution. You can leave dead beetles next to your plant to scare off future nibblers. Beware because they give off a strong unpleasant odor. An alternative is to vacuum beetles with a Shop-Vac with a soapy water solution on a long extension cord or with a rechargeable hand-held vacuum. Just ensure to dump the contents of the vacuum because the dead insects give off an extremely unpleasant odor. 

Hope these tips will help you survive the Japanese Beetle season!

4 comments

RE: GARY ENRIGHT
The product we linked in the blog post above is suitable to treat the japanese beetles during their grub/larvae stage. This product is used to control a wide variety of soil-living insects and aerial insects in their soil-living stag, aka grub phase.

Véronique Laporte July 28, 2020

This is quite informative but it leaves out information about where I can obtain the required HB nematodes. The link is to nematodes for grubs.

Gary Enright July 28, 2020

I have that pest for the past two years.
I take an empty jar of Nescafé, put the pot underneath the pest and tap with the cover on the critters. They fall inside the pot. Just put the lid over the pot and move to the next flower. Some fly away but most tumble in the pot.
This year, they ruined my rose bed and some are moving into the sunflower. What a pest.
They really stink after a while in the coffee jar.

Raymond Cote July 28, 2020

Japanese beetles

Nematodes is the only solution

Shanti Warner July 28, 2020

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