Yellow-starthistle
Guides
Chaetorellia
Chaetorellia is a genus of tephritid fruit flies (family Tephritidae) containing approximately 11 described species. Species in this genus are specialists on Asteraceae flower heads, with larvae developing within capitula and feeding on developing florets and seeds. Several species have been investigated or deployed as biological control agents against invasive thistles and knapweeds, particularly yellow starthistle (Centaurea solstitialis). The genus is characterized by distinctive morphological features and host-specificity patterns that have been taxonomically revised.
Chaetorellia succinea
False Peacock Fly
Chaetorellia succinea is a tephritid fruit fly native to the Mediterranean region that was accidentally introduced to the western United States in 1991. It has become established as a biological control agent of yellow starthistle (Centaurea solstitialis), a noxious invasive weed. The fly was not intentionally released due to concerns about potential attack on safflower (Carthamus tinctorius). It has been observed to feed on multiple Centaurea species and may competitively displace the related biocontrol fly Chaetorellia australis where both occur.
Eustenopus villosus
yellow starthistle hairy weevil
Eustenopus villosus is a small weevil in the family Curculionidae, widely known as the yellow starthistle hairy weevil. It is native to southern Europe and the Mediterranean region and has been introduced to the western United States as a biological control agent against the invasive weed yellow starthistle (Centaurea solstitialis). Both adults and larvae feed on the plant's reproductive structures, with larvae capable of destroying nearly all developing seeds within a single flower head. The species is considered one of the more effective biocontrol agents for this noxious weed.
Larinus curtus
Yellow Starthistle Flower Weevil
Larinus curtus is a small weevil native to southern Europe and the Mediterranean region, introduced to the United States in 1992 as a biological control agent for the invasive weed yellow starthistle (Centaurea solstitialis). Adults are dark brown to black with light-colored mottled hairs and measure approximately 6 mm in length. The species is univoltine, with larvae developing inside flower heads where they feed on developing seeds, achieving average seed reduction rates of 96% per infested head. While adults feed on flowers and pollen, the larval stage provides the primary biocontrol impact.