Nontarget-effects

Guides

• Trichosirocalus horridus

  Thistle Crown Weevil, Musk Thistle Crown Weevil

  Trichosirocalus horridus is a Palearctic weevil introduced to North America in 1974 as a biological control agent for exotic thistles in the genera Cirsium and Carduus. Native to Europe, it has established populations across the United States, particularly in Virginia where it spread from 609 km² in 1981 to 4,345 km² by 1985. Adults feed on thistle rosettes while larvae develop internally in stems and crowns, causing significant damage to host plants. The species has shown nontarget impacts, feeding on native Cirsium species in Nebraska and Tennessee at rates comparable to target weeds.

  biological-controlinvasive-species-managementweevilthistlenontarget-effectsclassical-biocontrolCeutorhynchinaeCurculionidaePalearctic-nativeNorth-America-introduced