Bangasternus orientalis

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Common Name: yellow starthistle bud weevil (1-3)
Order/Family: Coleoptera/Curculionidae (1-2)
Insect; beetle; weevil (1-3)
Genus species: Bangasternus orientalis
Origin: From Northern Greece.  They are native in Southern Eurasia, Mediterranean basin. (1-2)

Photo by N. Poritz, with permission.

Life Cycle:
Generation: There is one generation per year. (1-2)
Over wintering Stage: Adult, outside the host plant.  (1-2)
Egg Stage: A female may produce up to 470 eggs. (1-3) They are laid in late spring to early summer.  The single eggs are covered with a dark mucilage which is laid on or near scale leaves beneath the immature head buds at the tips of flowering shoots. (1-2)
Larval Stage: The hatched larvae tunnel through the scale leaf, the flowering stalk or peduncle, and into the flower head where they feed on receptacle tissue and developing seeds. (1-3)
Pupal Stage: Pupation occurs within the seed heads in chambers formed from damaged and undamaged seeds. (1-2)
Adult Stage: The adults are brown with yellow to whitish hairs that give a somewhat mottled appearance.  They are 4 to 6 mm (0.16 to 0.2 in) long, not including the snout.  Adults exit from the pupal chambers in the heads in late summer to over winter outside the host plant. (1-2)

Type of Damage to Host: The larval is the destructive stage. They tunnel through the scale leaf, the flowering stalk or peduncle, and into the flower head where they feed on receptacle tissue and developing seeds. (1-3)

Plant: Yellow starthistle (Centaurea solstitialis); Purple starthistle (Centaurea calcitrapa); (1-3) the purple starthistle record may be of a different host race/biotype of the weevil. (1-2)

Location of Attack: The seed head interior. (1-3)

Impact: The larval feeding reduces seed production.  Preliminary data indicate that a single larva destroys 50 to 60% of the seeds in a head.  (1-3)

Releases: The weevil was first introduced into the United States in 1985 in California, Idaho, Oregon, and Washington. (1-2)  Now Established in: California, Idaho, Oregon, and Washington. (1-2)

Habitat: Cool Climates (coastal, higher elevations and latitudes) are unfavorable.  The weevil is very available.  It is transferred when it is an adult.  For redistribution the adults can be swept or hand-picked from the host plant. (1-2)

Where and How to Purchase: Contact the Biological Control of Weeds, Inc. for purchasing the insect.  Contact them at .  You can also contact the government agencies that deal with weeds.  You can find contacts within the Montana Weed Fighters! links.

1.  Reese, Norman, et. al., Ed., Biological Control of Weeds in the West, Western Society of Weed Science, in cooperation with USDA ARS, MT Dept. of Ag, and MT State Univ. Color World        Printers, Bozeman, MT, Feb, 1996.

2.  Reese, Norman, et., al., Ed., Biological Control of Rangeland Weeds in the Northwest United States, Manuscript/Rough Draft. 1996.

3.  "Biological Control of Weeds, Inc." [online] Available:

4.  "Yellow Starthistle Bud Weevil."  Biological Control of Weeds, Inc., [online image] Available:, by N. Poritz, 1998.

by: Erin Olind      3/10/00

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