Milky Spore: How To Use It For Japanese Beetle Control [GUIDE]

Milky spore disease is a sickness only affecting Japanese beetle larvae but this is a very good thing if you have problems with a Japanese beetle infestation.

In this article, we explain what milky disease is and how to inflict it upon your Japanese beetle population. Read on to learn more.

Japanese Beetles feedingPin

Why Are Japanese Beetles Bad?

It doesn’t take many Japanese beetles to strip your plants bare in nothing flat.

What the beetles don’t get, their larvae will.

More on –> How To Kill Japanese Beetle Grubs

Japanese beetle grubs (grub worms) lurking beneath the surface of the soil in your yard or garden will devour roots and kill plants and grass roots from below.

Japanese beetle larvae are fat, white, C-shaped grubs.

Just as caterpillars are susceptible to treatment with Bacillus thuringiensis (Bt), Japanese beetle larvae are susceptible to treatment with milky spore.

It’s hard to kill adult beetles, but if you kill them before they become adults, your problem will be mostly solved.

How Does Milky Spore Bacillus Work?

Milky spore is an important part of integrated pest management (IPM), but it isn’t a modern phenomenon.

This natural bacterium (Paenibacillus papillae) has been in use by gardeners for a very long time, and it remains the go-to solution for killing off grub worms.

When you apply milky spore in little piles at regular intervals to the surface of your soil, it soaks into the ground and dissipates and reproduces.

The Japanese beetle larvae underground eat the burgeoning bacteria, and it turns their body fluids into a milky liquid, causing them to die.

As a bonus, when the grub worm dies, its body releases new spores.

Is It Safe To Use Milky Spore Bacterium?

It’s very safe to use this natural bacterium in your battle with Japanese beetles because they are the only organisms susceptible to this malady.

While milky spore is of no help at all with any other sort of white grub or beetle, it is extremely effective in getting rid of this particular pest.

Is It Safe To Use Milky Spore On Plants For Human Consumption?

The USDA has approved milky spore for use on beetle grubs.

Milky spore is the common name for the bacteria B. popilliae, the active ingredient in some pest control products used to control the Japanese beetle (Popillia japonica).

Milky spore pest control bacterium is completely safe to use in every square foot of your vegetable garden as a repellent.

Use a garden dispenser, drop spreader, or dispenser tube every so many square feet based on the product instructions for your lawn care and garden.

Is It Hard Or Expensive To Use Milky Spore Bacterium?

It is incredibly easy and thrifty to apply milky spore bacterium to your entire lawn and/or garden, and you only have to do it once every two or three years.

Once you have applied the bacterium to your lawn or garden, the natural organisms multiply and spread on their own and may not even need to be refreshed for a full decade.

How And When Should Milky Spore Bacterium Be Applied?

It’s best to apply the bacterium when your soil temperature is and will consistently remain 60° – 70° degrees Fahrenheit (15° – 21° C).

Apply it in autumn before the weather cools.

At this time, grub worms tend to feed very aggressively in preparation for winter.

This is the best time to give them a hearty meal of milky spore.

When applying bacterium do not to scatter evenly over the ground.

Instead, place small piles at regular intervals over the entire surface of the ground you wish to treat.

Your goal is to form a gridwork of milky spore stations.

Apply the powdered bacterium using a teaspoon and simply drop a teaspoonful every 4’ feet in a grid pattern over the entire area.

Alternatively, create one of these handy-dandy DIY milky spore dispensers as shown in this video.

After applying the powder to the surface of your lawn, or garden, water well with a gentle spray from your garden hose.

You should water for approximately fifteen minutes to make sure the powder is watered in thoroughly.

Will Milky Spore Bacterium Kill Off All Of The Japanese Beetles In My Yard?

Unfortunately, if you have Japanese beetles and need grub control, you will never be rid of them entirely. However, applying milky spore bacterium grub killer will kill off most of the grubs of japanese beetles lurking beneath your soil.

This will also work on killing June Bugs.

When you kill them off before they get old enough to reproduce, you will sharply reduce their numbers.

Of course, Japanese beetles may be breeding and laying eggs in nearby properties and may fly in to damage your garden, but when you treat your soil, remember the bacterium will reproduce on its own and will gradually spread out from your property to form a bit of a safe zone.

You’ve Got Nothing To Lose!

The bottom line is there is no reason not to use milky spore powder bacterium to decimate the Japanese beetle grub worm population and reduce the number of Japanese beetles in your yard.

They are not beneficial insects. Just be sure to apply it at the right time and in the proper manner for the most effective results.

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