Milky spore does not kill or harm earthworms. This is because milky spore contains Paenibacillus popilliae bacteria that only causes milky spore disease in Japanese beetle grubs. Other insects, microorganisms, worms, birds, pets, and humans cannot be harmed by milky spore. If you use a grub-killing pesticide instead of milky spore, it will kill beneficial earthworms in your soil. This makes milky spore the safest treatment for Japanese Beetle infestation.
Why is Milky Spore Safe for Earthworms?
Milky spore won’t harm earthworms because the Paenibacillus popilliae bacteria in milky spore only causes disease in Japanese beetle grubs. When earthworms eat soil that contains milky spore, it will pass through their intestinal tract without causing any harm or disease.
- Milky spore contains a bacteria that is harmless to earthworms.
- The bacteria in milky spore will only harm Japanese Beetle grubs.
- Milky spore is organic, safe for people and pets, and won’t harm your soil ecosystem.
In the same way salt will kill slugs but won’t harm humans, milky spore will kill Japanese beetle grubs but won’t harm any other life form. It’s an organic lawncare solution that won’t harm beneficial pollinators, worms, or other helpful insects.
What Will Milky Spore Kill?
Japanese beetle grubs are the only organism that will be killed by milky spore. This is great news because Japanese beetles are invasive to North America. They are harmful to native species and plants, so killing them is a benefit for the ecosystem.
- Only Japanese beetle grubs will be killed by milky spore.
- Since Japanese beetles are invasive to North America, using milky spore is a benefit to native plants and other species.
- Unfortunately, milky spore won’t kill other species of harmful grubs.
As a negative, milky spore will only attack one species of beetle grub. If your plants are being attacked by another species of beetle grub—or by adult Japanese beetles—milky spore won’t provide any benefit.
How Do You Know if Your Lawn Needs Milky Spore?
To determine if your lawn needs milky spore, first search for Japanese Beetle grubs under the soil surface. Start at a dead area in your lawn or garden. Dig up the top 6–12 inches (15–30 cm) of soil. Search for grubs in the dirt. If you spot any grubs with white bodies and orange heads, it is extremely likely you have a Japanese beetle infestation that can be solved with milky spore.
- Use milky spore to destroy infestations of Japanese Beetle grubs.
- Japanese Beetle grubs feed on roots, which causes grasses and plants to yellow and die mysteriously.
- Dig up the top layer of soil near dead plants to search for beetle grubs.
If you do not treat your yard with milky spore, Japanese beetle grubs will eat the roots of your grass and plants. This will result in massive dead spots in your lawn and garden. Before you apply milky spore in your yard, check out our article on milky spore powder vs granules. We break down which application method is easier to use, more effective, and less expensive.
Do Grub-Killing Pesticides Kill Earthworms?
Pesticidal treatments that prevent or kill grubs in the soil are deadly to earthworms. Studies have shown that halofenozide (an ingredient in Mach 2) is harmful to earthworms. Additional scientific studies show the grub-preventer imidacloprid (the active ingredient in Merit) is highly toxic to earthworms. So, both of these grub-preventers will also kill earthworms.
- Pesticidal grub-preventers and grub-killers are deadly to earthworms.
- Scientific studies show evidence that pesticidal grub treatments destroy beneficial insect populations.
- If you are looking to kill grubs without harming earthworms, use milky spore or another natural treatment.
Pesticides designed to kill active grub populations will also wipe out helpful earthworms. Trichlorfon, which is in the grub-killer Dylox, kills earthworms. Carbaryl is a popular active ingredient in grub killers, but the National Pesticide Information Center states that carbaryl is highly toxic to earthworms. So, there are currently no pesticidal treatments on the market that will kill grubs without harming earthworms.
Is There an Earthworm-Safe Alternative to Milky Spore?
If your lawn is being attacked by grubs and milky spore is not effective, use Bt (Bacillus thuringiensis). Like milky spore, Bt is a bacteria that attacks specific insects. Unlike milky spore, Bt kills a wider range of grubs and insects. However, it is still harmless to earthworms.
- Bt (Bacillus thuringiensis) bacteria is the best alternative to milky spore.
- You can kill several species of grubs with Bt without harming any earthworms.
- If your grub problems aren’t solved by milky spore, use this Bt spray to treat your lawn.
In many cases where milky spore is ineffective, it is because you have grubs attacking your yard that are not Japanese beetle larvae. Since milky spore only attacks Japanese beetle grubs, other species won’t be harmed by it. Bt targets and kills these other grubs, but it is still a safe, organic solution that won’t harm helpful earthworms, your pets, or your family.
How Do You Get Rid of Earthworms?
All pesticides designed to kill grubs also kill earthworms. However, you should not make it your mission to kill earthworms. Earthworms are extremely beneficial to the soil, your plants, and the environment. Earthworms do not harm plants and grasses. In fact, earthworms loosen the soil as they tunnel. This allows more oxygen and water to penetrate the soil, which results in healthier plant and grass roots.
- You should never attempt to kill earthworms.
- Earthworms improve soil quality and help promote healthy grass and plant growth.
- Grub-killing pesticides kill earthworms, so these products should be avoided.
- Use bacterial grub killers—like milky spore and Bt—to kill grubs and protect earthworms.
To maintain a healthier lawn and garden, do everything you can to avoid killing earthworms. This means it is best to avoid using pesticides to attack a grub infestation. Grub-killing bacteria such as milky spore and Bt are great choices because they will not kill off any of the helpful earthworms in your yard.
Will Milky Spore Hurt Earthworms?
If you are considering using milky spore in your yard but aren’t sure if it’s safe for earthworms, check out these must-know facts:
- Milky spore is completely harmless to earthworms.
- The only organism that is attacked by milky spore is the Japanese beetle grub.
- Worms, other insects, spiders, birds, reptiles, fish, and mammals are all unaffected by milky spore.
- Milky spore is highly effective at killing Japanese beetle grubs.
- Pesticides made to kill grubs will kill earthworms.
You can keep your lawn safe for earthworms and all other beneficial critters by using milky spore. Since it only attacks one harmful species, milky spore is an environmentally friendly lawn care tool.