Bug FAQMarbled Piercer
Cydia splendana · Order: Lepidoptera · Family: Tortricidae
The chestnut tortrix (Cydia splendana) is a small moth with a wingspan of about 12 to 16 mm. It lives in Europe, where the adults fly from May through September and the larvae feed on oak, sweet chestnut and sometimes walnut, developing inside mature chestnut fruits. It is also called the acorn moth, a name that can be confused with the North-American Blastobasis glandulella.
Source: Wikipedia
How to recognize it
Cydia splendana, known as the chestnut tortrix, belongs to the family Tortricidae.
Source: Wikipedia
Size
Its wingspan measures roughly 12 to 16 mm.
Source: Wikipedia
Where it lives
It is found throughout Europe.
Source: Wikipedia
What it eats
The larvae feed on oak, sweet chestnut and possibly walnut species. They develop mainly inside mature chestnut fruits.
Source: Wikipedia
Life cycle
Adults are on the wing from May to September, with exact timing depending on location.
Source: Wikipedia
When you see it
The flight period spans May through September, varying by region.
Source: Wikipedia
Where it comes from
Its native range is Europe.
Source: Wikipedia
Lookalikes
It is also called the acorn moth, a name that can refer to the North-American Blastobasis glandulella, which belongs to a different family.
Source: Wikipedia
Where it is found in the US
Recorded in 1 of 51 states and DC. Most records: New Jersey.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
More photos
Questions people ask
When are adult chestnut tortrix moths active?
Adults fly from May through September, with the exact timing depending on where they are found.
Source: Wikipedia
What do the larvae of Cydia splendana eat?
The larvae feed on oak, sweet chestnut and possibly walnut, and they develop mainly inside mature chestnut fruits.
Source: Wikipedia
What other insect is sometimes called the acorn moth?
In North America, the name acorn moth can also refer to Blastobasis glandulella, which is in the family Blastobasidae.
Source: Wikipedia
Same family (Tortricidae)
Oblique-banded Leafroller MothChoristoneura rosaceanaDamages trees, gardens or crops
Garden TortrixClepsis peritanaDamages trees, gardens or crops
Common MarbleSyricoris lacunanaDamages trees, gardens or crops
Red-banded Leafroller MothArgyrotaenia velutinanaDamages trees, gardens or crops
Light Brown Apple MothEpiphyas postvittanaDamages trees, gardens or crops
Aster and Reddish Eucosma Moths and AlliesEucosma parmatanaSources
- Wikipedia: https://en.wikipedia.org/wiki/Cydia_splendana
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.