Even moderate infestations of black grass bugs may offer significant competition with livestock for rangeland forage. Several species of black grass bugs exist in Colorado, with the most common being Labops hesperius Uhler. Thirty-four species of Labops and Irbisia are known from North America. L. hesperius has buff coloration on the outer margins of the wing covers. I. brachycera is jet black in color, with no markings.
Immature stages are similar in appearance to the adults, but smaller.
Black grass bugs damage plants in the spring by piercing and sucking the contents of cells. Within seconds of the start of feeding, a whitish spot appears at the site from the destruction or removal of chlorophyll. The bugs begin feeding at the leaf tip and proceed downwards, feeding with the head pointing down. Most feeding is done on the upper surface of the leaf. Damaged leaves may appear straw colored, as if they have been damaged by frost.