How to kill grubs in the fall

Updated April 17, 2017

Grubs are larvae that have not yet undergone metamorphosis into beetles. Early fall is when grubs begin showing up in your lawn, so early autumn or late spring are the best times to implement grub control. Grubs damage lawns by feeding on grass roots. When this happens, you will notice patches of brown grass that is easy to remove. Grubs come in many varieties, so identifying what type of grub is infesting your lawn is essential to finding the most effective treatment.

Take a sample of grass from your lawn by cutting ΒΌ of a square foot from the turf. The perfect time to do this is between early August and mid-September because adult beetles lay their eggs in July.

Cut more than one sample to ensure that you treat only the places where grubs are infesting. Grubs are known for infesting patches of grass rather than entire yards.

Collect the grubs from the lawn and place them in a clear glass jar. You will want to refer to different illustrations of grubs to ensure that you identify the correct species.

Use your magnifying glass to identify the species of grubs infesting your lawn. Once you make proper identification of the species, you can then plan your attack against the grubs.

Use Dylox to kill white grubs. Dylox is a substance that quickly gets rid of white grubs. One downside to Dylox is that it loses its potency in hard water or in soils with pH levels of 9 or higher. Therefore, timing is crucial when using this substance with high pH levels and hard water.

Apply the Dylox to patches of grass where grubs are prominent. Work quickly. The active ingredient in Dylox has a tendency to degrade to 50 per cent of its potency within 30 minutes once it makes contact with hard water or high pH soils.

Wait a few days to see how the lawn treatment works. Do not attempt to treat the lawn with lime before or after using grub killer such as Dylox. This is because lime contains high pH levels, which can affect how well the grub killer works at getting rid of grubs.

Use predatory nematodes as an organic treatment for killing white grubs when you don't want to risk harming other wildlife that may feed on them, including earthworms, birds, skunks and raccoons.

Water the lawn using a spray hose or sprinkler system. The lawn should be moist before application. It is also important to do this treatment at night. Predatory nematodes are sensitive to light and will be killed by direct sunlight.

Check the soil temperature using a thermometer. The most effective soil temperature for this particular treatment is between 12.8 and 29.4 degrees Celsius.

Mix the solution of the predatory nematodes and wait an hour before applying it to the lawn. To ensure maximum effectiveness, use the solution within three hours of mixing.

Water the lawn after you apply the predatory nematode solution. You should be able to see how well the solution is working within two days of using it.


Most chemical grub killer treatments must use water to be effective. Read the directions on the grub killer you are using to ensure proper application.

Things You'll Need

  • Lawn shears
  • Gardening gloves
  • Magnifying glass
  • Glass jar
  • Photos of species of grubs
  • Dylox
  • Garden hose
  • Thermometer
  • Predatory nematodes
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About the Author

Victoria Ramirez has been writing professionally since 2009. She has a background in health and human services, and contributes her expertise to several online publications. Ramirez received her Bachelor of Arts in psychology from California State University, Bakersfield, where she graduated with honors in 2004.