Introduction
 The musk thistle and plumeless thistle were introduced to the US from Europe and Asia.  Musk thistle and plumeless thistle are very difficult to tell apart.  They were first discovered in Tennessee in the 1940’s and have spread to many states since then.  These two thistles are biennials that form a rosette in the first year and in the second year they send up a reproductive stalk from the rosette.  This stalk bears the flowers which can produce up to 120,000 wind dispersed seeds per plant.  In warmer climates the thistle can have an annual life cycle, in other words, it will send up a stalk the same year it produces the rosette.

Environmental Impacts
 The musk and plumeless thistles are completely unpalatable to grazing livestock.  In overgrazed rangeland, they can completely take over the forage that animals need.  They spread very rapidly because of the high amount of seeds produced per plant and because the seeds are dispersed by the wind.  Both weeds are noxious in Nebraska.

Remedial Action
 There are many ways to control these thistles.  They can be controlled by mechanical, chemical, and biological means.  Mechanically controlling the musk and plumeless thistle is very labor intensive and is probably only effective on small areas.  Chemical control is the most widely used control method for these thistles.  Any chemical that will control broadleaf weeds such as 2,4-D, and Tordon will control musk and plumeless thistle and leave the native grasses unharmed.  There are some biological controls that work on the thistles.  Two weevils have been released that feed on these thistles but research has indicated that they also feed on native thistle species.