How to Manage Pests

UC Pest Management Guidelines

Small Grains

Stink Bugs

Scientific name: Euschistus spp.

(Reviewed 2/07, updated 2/07)

In this Guideline:


Stink bugs are medium to large-sized bugs. Those that attack small grains are commonly grey brown to green in color and 0.38 to 0.5 inch long. Their bodies have a characteristic shield shape with a large triangle on the center back. They are most common where cereals are planted adjacent to rangeland near the foothills or desert.


Damage usually occurs when stink bugs feed in the head during milk or soft dough stage.


Observe fields frequently after heading, particularly those adjacent to desert or rangeland. If vegetation in areas surrounding the field is beginning to dry up, make more frequent observations. Using a sweep net, sample the margins, then move toward the center of the field; initially, stink bugs are generally confined to the edges of the field.

Management Decisions
No economic thresholds have been established for stink bug. No chemicals are currently registered for use against stink bug on barley, wheat, oats, or rye.


[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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