July 20, 2023 5 min read

Often homeowners face various lawn problems like a change of shade in their turf grass, brown or yellow patches, increased pest species, etc. Lawn grubs are one of the reasons behind this. If you want to save your lawn or vegetation, you must learn how to eliminate them.  

What are lawn grubs?

Grubs are white, small, worm-like larvae of beetle species, particularly Japanese beetlesEuropean chafer beetles, and June beetles. Identifying the individual beetle species by their grubs is very difficult as they look almost identical.

 

 

They became dormant during the winter but when the weather starts to warm up they come alive. During the spring and early summer, grubs eat grass and other vegetation roots, causing wide-range plant damage. This kills your grass until it turns into unpleasant brown patches.

When grubs turn into adult beetles, they leave the soil to mate and lay eggs. Adult beetles lay their eggs near their feeding sites, creating new grubs and that’s how the whole life cycle works for grubs to spread the infestation.

What are the signs you have grubs in your lawn?

To make sure you have a grub problem these are the signs you need to watch out for,

 

  • Brown patches
  • Yellowing grass
  • Grass with no roots
  • Unforeseen amount of holes in your lawn caused by animals (birds, raccoons, skunks, etc.) digging in the grass to get to the grubs
  • Increasing numbers of moths or beetles flying around at grass level

 

How to eliminate them naturally?

Rather than use harmful chemicals you can treat your lawn in natural ways.

1. Soil-testing— First, dig up a section of grass from the damaged area about 1 square foot large and 3 inches deep. If you have grubs, you’ll see them.

 

  • Fewer grubs—no need to worry about that and no treatment necessary.
  • More than 10 grubs-- You will know you have a serious infestation if you see more than 10 grubs in exposed soil.

 

2. Uses of Nematodes— Nematodes are microscopic, parasitic worms that feed on grubs. It is a long-term solution because they reproduce on their own and continue feeding on grubs (and other pests) for years.

 

  • Choose beneficial nematodes that work against grub worms.
  • Blend it with water and apply it with a garden sprayer on the lawn.
  • Spray the nematodes on a grub-infested lawn late afternoon or in the evening.
  • After applying, water your lawn adequately to keep it moist.

 

You can buy them through gardening stores, nurseries, and online.

Important tip- Apply nematodes only in the evening or late afternoon because they get killed by light and heat. Also, make sure the soil temperature is above 60°F before applying it.

3. Milky spore— A milky spore is an excellent way to control white grub populations because it is an eco-friendly, non-toxic option. It is a bacterial disease that targets the larval stage of Japanese beetles. This bacterium won’t harm your other plants but is deadly only to Japanese beetle grubs.

 

  • Add milky spore to the lawn when the soil is between 60 and 70 degrees Fahrenheit. 
  • Simply sprinkle the dry powder directly onto your lawn 
  • After that, water the lawn for 10 minutes.
  • For best results, you’ll need to apply milky spore a few times a year for about 2-3 years. It isn’t a quick fix, you need to be patient for that.

 

It’s widely available at garden centers, home improvement stores, or even online retailers. 

Important tip- Milky spore doesn’t work on all grubs, only on Japanese beetles. Before applying you need to be certain that you have Japanese beetles on your lawn.

4. Attract predators— Encourage natural predators of grubs, such as birds, skunks, and other animals that feed on them, to visit your lawn. Add bird feeders, birdbaths, and birdhouses around your yard. This will attract beneficial bird species and help keep your yard’s grub populations in check.

5. Apply neem oil— Neem oil is another pest control option. It has insecticidal properties and is effective in repelling grub worms in lawns and gardens. This natural pesticide deters grubs from feeding, laying eggs, and growing into adults, thus breaking their cycle and helping in their control and stopping lawn damage.

 

  • Mix the neem oil with water
  • Spray it on a grub-infested lawn using a hose. 
  • Apply over the areas with dead patches of grass to make sure you target the larvae.

 

How to prevent grubs in your lawn?

1. Dethatch and aeration—Thatch, the layer of grass clippings and other debris that builds up in your lawn over time, is a hotspot for pests, including grubs. Removing the thatch, not only eliminates grubs but also helps make it easier for milky spores, nematodes, and other natural grub-killing methods to be more effective. Aerating the lawn creates a less welcoming environment for the pests.

2. Fertilize and reseed— If your lawn has suffered significant damage due to grub feeding, reseed the affected areas once you have addressed the grub problem. Beetles don’t tend to lay eggs in grass that’s long and thick. By seeding and fertilizing your lawn, you can repair any damage.

 

Grub infested area to reseed

 

 

  • In spring and fall, dethatch dead grass from any brown patches. 
  • Water your lawn, then sprinkle new grass seed over any thin or dead areas.
  • After reseeding, fertilize the lawn to help the dead patches restore and the new seeds to prosper.

 

3. Don’t overwater— Don’t overwater your lawn because too much water attracts pests, and lawn diseases, which are more vulnerable to grub damage. Also, many grubs lay eggs in July, so it’s especially important to keep your lawn dry in July and August. The eggs need moisture to survive and hatch later on, and they will die without it.

Important tip— if your lawn is positioned in shady areas (like backyards) where sunlight doesn’t reach that much, you need to be careful how to water your lawn. If your soil is already moist then don’t overwater it otherwise it will welcome various lawn diseases and pest problems.

4. Mow at the right height— Keep your grass about two inches long. Raise the blades on your lawnmower to increase the length that it will cut the grass. Because beetles don’t like long grass for egg-laying, so let your grass grow a little longer than normal.

---- Remember, using chemical insecticides should be the last resort if the infestation is severe and should be done following the manufacturer's guidelines to minimize environmental impact and ensure your safety. If you are unsure how to proceed, consider seeking help from a professional lawn care service.