Biological agent type
Yellow starthistle flower weevil.
Plant species attacked
yellow starthistle (Centaurea solstitialis)
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Image by Eric Coombs, Oregon Department of Agriculture.
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If images are downloaded and used from the ODA web site please be sure to credit the photographer.
Site of attack
Seed heads.
Mode of attack
Adults feed on the florets and the larvae in the seed head, reducing seed production.
Destructive stage
Larval-internal.
Collection and release information
This bio agent is wide spread and adults can be collected by sweep net June-July. Consult with ODA for availability for your area.
History in Oregon
The seed head weevil Larinus curtus was released in Douglas and Baker Counties in 1992 and found established at both sites in 1993. An additional release was made in Wasco County in 1993, which was recovered in 1994. Collection for redistribution from the Baker and Wasco Based upon difficulty with establishment, this weevil does not appear to do well in Southwest Oregon.
Release status in Oregon
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