How to Manage Pests
UC Pest Management Guidelines
Black Grass Bug
Scientific name: Irbisia spp.
In this Guideline:
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 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.
No economic thresholds have been established. No pesticides are registered for treatment of
black grass bug on small grains.
UC IPM Pest Management Guidelines: Small Grains
UC ANR Publication 3466
Insects and Mites
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
L. D. Godfrey, Entomology, UC Davis
Acknowledgment for contributions to Insects and Mites:
D. Gonzalez, Entomology, UC Riverside
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