Milky Spore Vs. GrubEx [Which is Better?]

GrubEx is a more versatile grub-killer than milky spore, but it is much less safe for the environment because it kills helpful insects. The bacteria in milky spore only targets Japanese beetle grubs and will not harm any other organisms. Milky spore lasts longer in the soil, costs less to use, acts quickly, and is just as easy to spread as GrubEx. So, if you are certain you are fighting a Japanese beetle grub population, use milky spore. Then, if the grub problem persists, follow up with GrubEx.

Milky spore vs GrubEx

How Does Milky Spore Work?

Milky spore products are not pesticidal. Instead, they contain the Paenbacillus popilliae bacteria that causes the deadly milky spore disease in Japanese beetle grubs. When you spread milky spore on your lawn, you introduce this bacteria into the soil. Once there, the bacteria in milky spore flourishes and kills grubs for years to come. Plus, it’s harmless to people, pets, and beneficial insects.

How Does GrubEx Work?

GrubEx is a pesticidal grub killer containing the active ingredient chlorantraniliprole. Spreading GrubEx treats your lawn with this chemical pesticide that attacks grubs, caterpillars, and other insects. The chlorantraniliprole in GrubEx causes insect muscle cells to leak calcium, which paralyzes and kills the grubs and other insects.

GrubEx Vs. Milky Spore: Head-to-Head Comparison

Before treating your lawn with either milky spore or GrubEx, check out our complete breakdown. Here, we compare the effectiveness, cost, and safety of using each of these products. Then, we will choose a winner between these two products.

Does GrubEx Kill More Grubs than Milky Spore?

Two bags of GrubEx laying on my lawn.
Two bags of GrubEx laying on my lawn.

GrubEx kills a wider range of grubs and other insects than milky spore. This is because milky spore only attacks and kills Japanese beetle grubs. Other grubs and insects won’t be harmed at all by milky spore powder. So, if the white grubs in your lawn come from a European chafer beetle, or another species, milky spore won’t provide any benefit.

  • GrubEx kills a wide variety of grubs and insects.
  • Milky spore only kills Japanese beetle grubs—all other species will be unharmed.
  • GrubEx has the capability to kill more pests than milky spore, but using it will also kill helpful pollinators.
  • Milky spore will kill Japanese beetle grubs without harming butterflies and bees.

GrubEx kills a wide range of insects. Many species of grubs will be killed by GrubEx, which makes it useful if you do not know the species of grub damaging your lawn. GrubEx also kills moth and butterfly caterpillars. So, using GrubEx can be a positive if you need to kill several pests, but the side effect is that you will kill helpful pollinators.

Winner: GrubEx

Does GrubEx Work Faster than Milky Spore?

Both milky spore and GrubEx begin working almost immediately after application. However, GrubEx has a more powerful first application that will kill large amounts of grubs quickly. Milky spore may require multiple applications to build up a large population of P. popilliae bacteria, so you may have to wait longer to see results when you use milky spore.

  • GrubEx begins working 10–14 days after application.
  • Milky spore starts to kill grubs 7–21 days after it is applied.
  • GrubEx will kill more grubs after the first application than milky spore.
  • Milky spore may require multiple applications to reach peak grub-killing strength.

GrubEx starts to kill grubs in 10 to 14 days. Milky spore begins killing Japanese beetle grubs in 7 to 21 days. So, both products work quickly. That said, you’ll see more drastic results with GrubEx. Milky spore may require a bit more patience before you see a decrease in the grub population.

Winner: GrubEx

Does Milky Spore Last Longer than GrubEx?

Milky spore is a much longer-lasting grub killer than GrubEx. After treating your lawn with milky spore for 2 to 3 years, you will create a self-sustaining milky spore bacteria population that remains active for up to 20 years without any more work. In comparison, GrubEx must be reapplied annually to remain effective.

  • Milky spore remains active in the soil for 10–20 years after the initial application schedule.
  • GrubEx lasts for 1 year.
  • Applying milky spore annually for 2–3 years builds up a self-sustaining grub-killing bacteria population in the soil.
  • The pesticide in GrubEx leaches out of the soil within 1 year.

The reason milky spore lasts for a surprisingly long time is that it is a bacteria that can exist in the soil, killing grubs for many years after application. GrubEx is a chemical pesticide that eventually washes out of the soil. So, you can create a long-lasting anti-grub barrier with milky spore that can’t be achieved with GrubEx.

Winner: Milky Spore

Is GrubEx Easier to Use than Milky Spore?

Both milky spore and GrubEx are very easy to apply to your lawn. For milky spore, use a lawn and garden dispenser tube to apply a small mound of milky spore powder every 4 feet in your lawn, in a grid pattern. Then, water your lawn to pull the powder into the soil.

  • GrubEx and milky spore are equally easy to apply.
  • You will need this lawn and garden applicator to apply milky spore powder in your lawn.
  • This lawn spreader is the best tool for spreading GrubEx.
  • Both milky spore and GrubEx must be watered in after application.
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To apply GrubEx, use a lawn spreader designed for seed or fertilizer to spread the granules according to the rates on the packaging. Then, water the GrubEx into the soil so it can start killing grubs. Since both of these products can be applied easily, there is no clear winner in this category.

Winner: Tie

Is Milky Spore Safer than GrubEx?

Milky spore is much safer for the environment and your soil health than GrubEx. This is because milky spore is a natural, organic product without side effects. It will kill Japanese beetle grubs but milky spore is safe for earthworms, bees, and butterflies. This allows you to kill grubs without destroying the soil organisms and pollinators.

  • Milky spore is far safer to use than GrubEx.
  • The bacteria in milky spore is completely harmless to all organisms except the Japanese beetle grub.
  • GrubEx contains chlorantraniliprole, a pesticide that kills pollinators, harms earthworms, and pollutes waterways.

The chlorantraniliprole in GrubEx is considered low toxicity to mammals by the National Pesticide Information Center. That said, it has been known to cause tumors in test animals, trigger gene mutation, kill butterflies and bees, and studies have shown that it has a high risk of harming earthworms. So, if you wish to grow a chemical-free yard, don’t use GrubEx.

Winner: Milky Spore

Is Milky Spore Less Expensive than GrubEx?

Milky spore is less expensive to use than GrubEx because milky spore lasts for many years after application. In comparison, GrubEx must be used annually, which adds up to a larger cost in the long run. When we compared milky spore powder vs. granules we found that using the powder is far more cost-effective than using milky spore granules. Treating a 10,000-square-foot lawn with milky spore powder one time is slightly more expensive than treating the same area with GrubEx. So, on a single application basis, GrubEx wins.

  • It is much more cost-effective to use milky spore than GrubEx.
  • Compare the cost of this milky spore powder with this GrubEx—both products treat 10,000 square feet of lawn.
  • Milky spore powder only needs to be applied for 2–3 years, then it keeps working for 10–20 years.
  • GrubEx only works for 1 year, so you will spend more money reapplying it every year.
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When we look long-term, milky spore becomes much more cost-effective. Applying milky spore regularly for 2 to 3 years will inoculate your lawn against Japanese beetle grubs for 10 to 20 years, with no further applications required. Meanwhile, if you use GrubEx you will need to buy the product every year to do a repeat application. You’ll save hundreds of dollars by choosing milky spore.

Season-Long Protection
Scotts GrubEx | Season-Long Protection | Works Against Grubs, Caterpillars, and Japanese Beetles
  • Comprehensive protection against a wide range of grubs, webworms, and beetle larvae.
  • Effective, season-long control for a healthy and vibrant lawn.
  • Sizable coverage of up to 10,000 square feet, making it a cost-efficient choice.
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Winner: Milky Spore

Can You Use GrubEx With Milky Spore?

There is no problem with using GrubEx and milky spore simultaneously. If you apply milky spore and do not see positive results, then either your milky spore was ineffective or the grubs you are trying to kill are not Japanese beetle larvae. In either case, you can follow up with GrubEx to kill the grubs quickly. Using both products may slow the spread of the milky spore bacteria, but GrubEx will not ruin the effectiveness of your milky spore, or vice versa.

Should You Use Milky Spore or GrubEx for Your Lawn?

When choosing between milky spore or GrubEx, use these rules to plan your application:

  • Use milky spore if you are killing Japanese beetle grubs.
  • Milky spore only kills Japanese beetle grubs.
  • Use GrubEx if you are killing grubs that are not Japanese beetle larvae.
  • GrubEx kills Japanese beetle grubs and several other grub and insect species.
  • Both milky spore and GrubEx begin killing grubs within 2 weeks after application.
  • You can spread milky spore or GrubEx yourself with simple tools.
  • Milky spore can last up to 20 years in the soil, but GrubEx must be reapplied each year.
  • GrubEx contains pesticides that kill grubs, along with helpful insects and soil organisms.
  • Milky spore is pesticide-free and won’t kill helpful insects.
  • Because it needs annual reapplication, GrubEx is more expensive to use than milky spore.

In order to save money and protect beneficial insects, we recommend using milky spore as a first course of action against grubs. Allow the milky spore to work. If the grub damage in your lawn continues, then it’s time to use GrubEx to stomp out the pests.

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