Bug FAQLesser Knapweed Flower Weevil
Larinus minutus · Order: Coleoptera · Family: Curculionidae
Also called: Seedhead Weevil, Weevil
The lesser knapweed flower weevil is a small dark mottled brown beetle with a long snout, measuring about 4 to 5 mm long. It lives on knapweed plants across warm, dry parts of the western United States and feeds on the flower heads, where its larvae eat developing seeds. Adults are active throughout the summer, can live up to 14 weeks, and females lay up to 130 eggs in each flower head.
Source: Wikipedia
How to recognize it
Adults are dark mottled brown with a long snout.
Source: Wikipedia
Size
They are 4 to 5 mm (0.16 to 0.20 in) long.
Source: Wikipedia
What it eats
Adults feed on knapweeds, preferring diffuse knapweed. Larvae emerge and burrow into the flower head, feeding on the developing seeds.
Source: Wikipedia
Life cycle
Adults are active throughout the summer and can live up to 14 weeks. Females can lay up to 130 eggs, depositing them inside knapweed flower heads.
Source: Wikipedia
When you see it
The weevil is active throughout the summer months.
Source: Wikipedia
Lookalikes
In knapweed fields, this weevil also consumes the gall-forming flies Urophora affinis and Urophora quadrifasciata, which are other biological control agents.
Source: Wikipedia
Where it is found in the US
Recorded in 23 of 51 states and DC. Most records: Washington, Colorado, Montana, Oregon, Michigan, Pennsylvania, Idaho, Massachusetts.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What does the lesser knapweed flower weevil look like?
It is a dark mottled brown beetle with a long snout and measures about 4 to 5 mm in length.
Source: Wikipedia
What does the weevil feed on?
Adults feed on knapweed plants, especially diffuse knapweed, and the larvae eat the developing seeds inside the flower heads.
Source: Wikipedia
Same family (Curculionidae)
Green Immigrant Leaf WeevilPolydrusus formosusDamages trees, gardens or crops
Black Vine WeevilOtiorhynchus sulcatusDamages trees, gardens or crops
Nettle weevilPhyllobius pomaceusDamages trees, gardens or crops
Asian Oak WeevilCyrtepistomus castaneusDamages trees, gardens or crops
Strawberry Root WeevilOtiorhynchus ovatusDamages trees, gardens or crops
Common Leaf WeevilPhyllobius pyriDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Larinus_minutus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-27 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-27.