Agriculture: Small Grains Pest Management Guidelines

Black Grass Bug

  • Irbisia spp.
  • Description of the Pest

    Black grass bugs are small (0.2 to 0.33 inch long), shiny or grayish black bugs with black or red legs and prominent eyes.


    Feeding damage appears as whitish or yellowish patches on the leaves. The association of the insect with these damage symptoms confirms black grass bug damage.



    Check fields regularly throughout spring. If black grass bug is found, check the extent of the infestation by taking sweep net samples beginning at the field margin and progressing to the center of the field. Infestations are usually heaviest or entirely confined to the edge of the field.

    Management Decisions

    No economic thresholds have been established. No pesticides are registered for treatment of black grass bug on small grains.

    Text Updated: 02/07