How to Manage Pests

UC Pest Management Guidelines

Small Grains

Black Grass Bug

Scientific name: Irbisia spp.

(Reviewed 2/07, updated 2/07)

In this Guideline:


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 field 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.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Small Grains
UC ANR Publication 3466

Insects and Mites

L. D. Godfrey, Entomology, UC Davis
V. M. Barlow, UC Cooperative Extension, Riverside County and UC IPM Program

Acknowledgment for contributions to Insects and Mites:
D. Gonzalez, Entomology, UC Riverside
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier

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