Bug FAQGrass bug
Stenodema laevigata · Order: Hemiptera · Family: Miridae
Source: Wikipedia
Adult grass bugs are 7 to 10 mm long and are usually light-green, though they may appear yellow or brown. They live across the United Kingdom, Europe, and east through the Palearctic to northern China, where they feed on unripe grains and can harm crops.
Source: Wikipedia
How to recognize it
They are light-green, yellow or brown and lack femoral spurs, with a densely pitted prothorax.
Source: Wikipedia
Size
Adults measure 7 to 10 mm (0.28 to 0.39 in) in length.
Source: Wikipedia
Where it lives
They are common throughout the United Kingdom and the rest of Europe.
Source: Wikipedia
What it eats
Both adults and larvae feed on unripe grains such as Alopecurus, Dactylis, Festuca and wheat. Larvae may also suck juices from leaves and stems.
Source: Wikipedia
Life cycle
Larvae are light-yellowish, appear in summer and are active from May to July; new adults emerge by August and persist until the next spring.
Source: Wikipedia
When you see it
Larvae are active May to July, after which a new generation appears and lasts until the following spring. By autumn the bugs turn brown and begin overwintering.
Source: Wikipedia
Where it comes from
Their range extends from the UK and Europe east across the Palearctic through Asia Minor, the Caucasus, to northern China.
Source: Wikipedia
Where it is found in the US
Recorded in 1 of 51 states and DC. Most records: Virginia.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
More photos
Questions people ask
What crops can grass bugs damage?
They feed on unripe grains such as wheat, Alopecurus, Dactylis and Festuca, which can harm those crops.
Source: Wikipedia
When are grass bug larvae active?
Larvae are active from May through July before the new adult generation appears.
Source: Wikipedia
What colour are adult grass bugs?
Adults are usually light-green but may also be yellow or brown.
Source: Wikipedia
Where are grass bugs found?
They are common in the United Kingdom, throughout Europe, and extend east across the Palearctic to northern China.
Source: Wikipedia
Same family (Miridae)
North American Tarnished Plant BugLygus lineolarisDamages trees, gardens or crops
Red-spotted Plant BugDeraeocoris ruber
Alfalfa Plant BugAdelphocoris lineolatusDamages trees, gardens or crops
Meadow Plant BugLeptopterna dolabrataDamages trees, gardens or crops
Four-lined Plant BugPoecilocapsus lineatusDamages trees, gardens or crops
Lygus pratensisLygus pratensisDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Stenodema_laevigatum
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.