Grubs - When to Treat

Are you wondering the best time to Treat for Grubs: Spring, Summer or Fall?
You're not alone!

Many people are inquiring when they should treat their lawns!.

Here are the facts.

  1. The grubs are hard to kill at any time of the year with the traditional insecticides.
  2. The smaller and younger the grub, the easier it is to control them. Less insecticide is needed.
  3. The grubs do the most damage August through October when they are feeding and growing. Less damage is done at other times of the year. Control may be advised if skunks & raccoons tear up the lawn looking for them. (If anyone can get a crew of skunks or raccoons that are trained to remove grubs, eat them, and then put the sod back, wed be happy to hire them)
  4. Even if we could destroy all the grubs in your lawn now, this will not prevent the next generation of grubs from attacking your lawn the next season. See the life cycle chart. The grubs in your lawn now (generally are European chafer larva) will pupate in May and turn into adults in June. The adults are flying beetles. They go on mating flights, do what adult beetles do, then the females look for lawns on which to lay their eggs. Because they fly, the females from a lawn 3 doors away may still lay eggs on your lawn. There is no sure way to predict which lawns will have eggs laid on them in the summer.

Options & Recommendations

  1. If you treat for grubs in the spring, you must realize that another treatment may be necessary in the fall. It wont be the same grubs. As someone said, Its the kids that are always the problem.
  2. If grubs are found in the fall, we recommend treatment in the fall to minimize damage.
  3. Repair any damage. Overseed the bare or thin spots. April is a good time. May is still okay as long as the seed receives enough moisture. Fall seeding is the best, Spring is second best.
  4. Let nature control the grub population! Nematodes are earth-friendly microscopic worms which eat grubs at the larva stage. We've experienced a good control with this method when instructions are followed after proper application. Spring treatments begin when the ground temperature warms to approximately 50 degrees F.
  5. In July keep an eye out for the mating flights of the European chafers. They look like small June beetles. This indicates when the eggs will be laid and when the munching will begin.
  6. From early to mid August on, keep an eye on the lawn for damage. Again, nematodes can be applied at this time of year as an effective treatment.

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