Sod Webworm, or AKA Fall Webworm has been rampant in Kingwood TX killing entire lawns in 10 days or so. The stores can hardly keep the insecticide in stock. The clue is seeing small moths flying around in your lawn and beds. They lay eggs, then the moths eat the roots of your lawn. You can treat it with things like BugBGone, etc spray, but if you have a large infestation, you may have to resort to Cyonara spray. And then respray every week to 10 days as the cycle of hatching continues. Sad to say, if this is the case, your lawn will have to be replaced. Also if your neighbors aren't treating their lawn, you will have to retreat as I do every 2 weeks or 10 days.
