My front yard has large patches of dead grass. Originally I thought it might be a result of grubs, but dug down and didn't see any larvae or grub worms. The condition is worsening and now I've noticed pencil-eraser size holes throughout the dry areas. Do you know what this is and how to prevent or stop it?



I suspect the holes you see in the dry areas may be made by emerging lawn pests, such as billbug, but I'm not sure. The holes may also be from bird beaks as they forage for insects (yay, birds!) Here are some hints on how to scout and diagnose for billbugs and other lawn pests: Dig up a 6 by 6 inch square of your turfgrass, including 2 inches of soil, put it in a bucket and pull it apart, looking for any insects or larvae. Collect any/all you find. Identify the insects by referring to these USU Extension Fact Sheets:
Billbugs, at
White grubs, at
Sod webworm, at
Cranberry girdler, at

There's only one generation of billbug per year, they may be emerging as adults about now. Most of the damage is already done for the year, so if you don't find any pests in the turf sample, wait until next  May to treat for the pests. Once summer cools off (highs in the 80's), you should fertilize the affected areas to promote new growth and vigor, to repair the damage. Also, be sure to check the thickness of the thatch layer in your turf. If it's thicker than one-half inch, plan to have your lawn core aerated in early fall. Aeration helps promote thatch decomposition. Thatch is a protective habitat for the billbug, so it's best to minimize it.

Posted on 1 Aug 2007

Maggie Wolf
Horticulture Agent, Salt Lake County

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