Larinus planus

Larinus planus is a weevil, an insect of the Curculionidae family. It is native to Europe, and is also common in North America. Both the larvae and adults feed on flower buds, mostly of thistles. They are oval shaped, dark brown or black, and about 5-10 millimeters long.
The larvae stage does the most damage to the flower bud. In North America it has been used as a biocontrol agent.
"Larinus planus" has been used in North America to control the creeping thistle, a weed from Europe. It has spread to other plants. In 2000, it was found eating "Cirsium undulatum". This is a thistle native to western Colorado and eastern Utah. Later research found that it had reduced the amount of seeds produced by the native thistle. It has also been found to have a bad effect on "Cirsium pitcheri".
It is normal for introduced species to spread rapidly because they are free of the parasites and predators of their native land.