Trichosirocalus horridus is a species of true weevil

Curculionidae

Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...

, native to Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. It is a biological pest control

Biological pest control

Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...

 agent that was introduced into the United States in 1974 to control exotic thistles, especially in the Cirsium

Cirsium

Cirsium is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more accurately known as Plume thistles. These differ from other thistle genera in having feathered hairs to their achenes...

and Carduus

Carduus

Carduus is a genus of about 90 species of thistles in the family Asteraceae, native to Europe, Asia and Africa. Carduus is Latin for a thistle....

genera.

Life history

T. horridus feeds on the rosettes of thistles, with the larvae causing most damage to the plant.

Nontarget impacts

In 2004, T. horridus was observed feeding on the native thistle Cirsium altissimum L. in Nebraska. The weevil was observed on the native thistle at about the same rate as the targeted invasive thistle (Cirsium vulgare

Cirsium vulgare

Cirsium vulgare is a species of the genus Cirsium, native throughout most of Europe , western Asia , and northwestern Africa...

). T. horridus has also been observed feeding on 5 native Cirsium

Cirsium

Cirsium is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more accurately known as Plume thistles. These differ from other thistle genera in having feathered hairs to their achenes...

species in Tennessee.