I have seen lawns that have brown patches on lawns and lawns that are not greening up for over the 34+ years my company, Herbi-Systems, has been in operation. My industry colleagues have witnessed the same baffling occurrence.

Some brown patches on lawns have the appearance of being dead in areas as small as 10×10 feet, as well as in areas as large as an acre. Other brown patches on lawns appear dead on one side of a drive or sidewalk and untouched on the opposite side. In addition, there are lawns that appear dead in the backyard and not the front yard or vise versa, while some have a mottled appearance. There appears to be no discernible pattern of infestation. The possible exception is that dead areas often appear along property/mowing lines.

Problem:

Our management team is unsure as to the entire cause of the problem, but our knowledge and experience lead us to the following opinion (which is subject to change as we receive more information):

All brown patches on lawns show damage from the hunting billbug (Sphenophorus spp). Grass damaged by hunting billbugs will easily pull loose from the ground. This damage is detected by doing the “tug test,” then turning the grass over and looking at the roots. Later in the season, the blades will decompose so the turf can be wiped away, exposing just the soil. Billbug damage is confirmed by noting hollowed stolons, rhizomes, and roots. No other insect hollows these plant parts in turf. With a strong magnifying lens, chewed roots and other plant parts can be confirmed.