''Trichosirocalus horridus'' is a species of true weevil, native to

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. It is a

biological pest control Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or ot ...

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

Cirsium ''Cirsium'' is a genus of Perennial plant, perennial and Biennial plant, biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more precisely known as plume thistles. These differ from other thist ...

'' and ''

Carduus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' genera.

Life history

''Trichosirocalus 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'', commonly known as spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus ''Cirsium'', native throughout most of Europe (north to 66°N, locally 68°N), Western Asia (east to the Yenisei Valley ...

''). ''T. horridus'' has also been observed feeding on 5 native ''

'' species in Tennessee.

Life history

Nontarget impacts

References

Further reading