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How to get rid of the Japanese beetle

By Fafard

At the end of June, the sun is shining and you can finally enjoy the beautiful weather in your garden filled with flowers of a thousand colours... but oh my, what is happening to your plants? Only the skeleton of the leaves remains, everything has been devoured, literally destroyed. The culprit: the Japanese beetle, a polyphagous beetle that feeds on more than 300 species of ornamental plants, perennials, trees, shrubs and annual flowers.

The Japanese beetle can be distinguished from other beetles of the same family, such as the common chafer or the European chafer, by its colour: the thorax, abdomen and head of this insect are metallic green.

White worms and Japanese beetle

The problem begins in the early stages of development of the Japanese beetle. The larvae - grubs - cause significant damage to residential lawns. By feeding on the roots, they cause the death of the grass, in patches of varying size depending on the level of infestation. It is not uncommon for homeowners with grubs to have to completely redo their lawns at great expense to get rid of their grub problem. To learn more about grubs and how to control them, read our article.

How to recognize a Japanese beetle infestation?

At the beginning of summer, when temperatures oscillate between 21ºC and 35ºC, the adult beetles emerge from the ground to feed and reproduce in order to ensure the survival of the species. It is at this time that they can be seen flying left, often by the dozens, in the direction of light sources that attract them. It is difficult to know if they are Japanese beetles or other types of beetles, but if you see them busy in your trees, shrubs or flower beds, you can consider that you have an infestation and that it is better to act quickly.

A proven and effective solution to control Japanese Beetles

Until now, there have been no controls for adult beetles, and products to treat larvae were severely limited by the Pesticide Management Code and municipal by-laws. Adults had to be destroyed by hand by drowning them in soapy water and then applying an insecticidal soap solution, often daily. Unfortunately, this technique was not very successful in eliminating the problem and not having your plants damaged or even completely destroyed. We can now count on the Ortho Beetle B Gon Max ® Beetle Killer exclusive to Scotts Canada and available at garden centers. It contains naturally occurring soil microorganisms called Bacillus thuringiensis ssp. galleriae that effectively control several beetles including Japanese beetle, Asian garden beetle, Oriental beetle and rose beetle. After ingesting the leaves or roots treated with Ortho Beetle B Gon Max ®, the targeted insects stop feeding and die within a few days.

When and how to use Ortho Beetle B Gon Max®

The product can be used in two ways:

Foliar application

The best time to use the product is in June and July, when the adult beetles emerge from the ground and in August if they are still present. Multiple applications are often necessary, every week until the beetles disappear. To control the adults, the foliage of the affected plants should be thoroughly wetted while avoiding runoff.

Soil application by dipping

The product is also effective in controlling beetle larvae in the soil. The objective is to eliminate the larvae before they cause damage to the foliage of your plants. Simply apply the product to the soil to penetrate the root zone of the plants to be protected. Application can be made as early as early June to kill the previous year's larvae, and again in mid-August for newly hatched larvae. An additional application in mid-September can also help prevent a new infestation the following spring.

The product is applied with a sprayer after mixing with water. When used according to the label, this natural product has no impact on bees, ladybugs, butterflies and other beneficial insects in the garden.

This natural insecticide will keep your plants intact and allow you to enjoy the summer in the garden. There are also different strategies to limit the spread of beetle infestations such as maintaining a dense and healthy lawn to make it more difficult for the larvae to lay eggs and hatch, and turning off the lights in the yard during the breeding season to keep the insects away from your landscape.