Musk Thistle: Natural History and Management

Musk Thistle or Nodding Thistle (Carduus nutans) belongs to the sunflower family (Asteraceae). This species is a biennial generally requiring two years to complete its life cycle. These flowers are native to Europe and Asia, but are now a common agricultural pest throughout the United States and much of southern Canada. Musk Thistle was introduced to North America in 1853. Throughout most of its range C. nutans is considered a noxious weed, but is sometimes cultivated in gardens for its showy flowers.


Musk thistle management consists of mechanical, chemical, and biological control methods. Mowing and hoeing tend to be expensive. Herbicide control has been effective and is probably the most common. Several biological control methods have been successfully implemented using insects including: the Thistle Head Weevil (Rhinocyllus conicus), Musk Thistle Rosette Weevil (Trichosirocalus horridus), Musk Thistle Flower Fly (Cheilosia corydon), and the Musk Thistle Leaf Beetle (Phylliodes chalcomera).


References:

Boldt, P. E., and J. A. Jackman. 1993. Establishment of Rhinocyllus conicus Froelich on Carduus macrocephalus in Texas. Southwestern Entomologist 18(3): 173-181.

Cory, V. L. 1940. Six thistles recently introduced into Texas. Madrono 5: 200-201.

Department of Entomology. 2003. Biological control of weeds in Texas. http://bc4weeds.tamu.edu/weeds/rangeland/muskthistle.html.

Jackman, J. A., P. Boldt, J. W. Stewart and T. W. Fuchs. 1992. Biological Control of Musk Thistle in Texas. L-5067. Biological Pest Control. Texas Agricultural Extension Service. Texas A&M University System, College Station, TX.