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Lawn infestation #866824

Asked May 02, 2024, 6:43 PM EDT

Hi! I read one of the extension articles, “White grub control in lawns”, from Aug 19,2020. I live in St Louis Park and have this problem. Crows are digging and eating the big white grubs. I also saw the grubs when I raked the front yard this spring. There are multiple bare spots. I have a couple questions: Can you suggest a more natural solution, as I do not use pesticides? Will the grubs (or beetles) harm the young trees that I am soon going to plant? I’m planting apple trees, birch trees, juneberry shrubs, a redbud tree, and lilacs. I’d appreciate any advice you have for me.

Hennepin County Minnesota

Expert Response

For non-pesticide control, the U of Wisconsin suggests

Non-Chemical Control: Water and fertilize turfgrass areas optimally to help them tolerate white grub feeding. In addition, be sure to mow at the correct height and at the correct frequency to encourage deep root growth. Finally, be sure to properly reseed damaged areas as needed. 

Cornell says: 

Above all else, the best defense against grubs is to mow high, between 3.5 and 4 inches, no shorter, and to leave the clippings on the lawn. This makes the grass strong enough to withstand some grub feeding without dying off in the spring. After the second year, higher mowing usually results is a big drop in weed pressure, as well as a drastically reduced need for nitrogen fertilizer. 

The grubs sometimes feed on young and newly-planted trees as the roots are small and attractive to the insects.  You may want to wait until you get the grub problem under control before planting new trees.
Diane M Replied May 04, 2024, 8:41 AM EDT

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