Canada Thistle (Cirsium arvense)

Canada Thistle is a noxious and invasive perennial weed that propagates primarily through an extensive and robust root system. Control of Canada Thistle is a particular challenge in sustainable and organic farming systems where herbicides are restricted or prohibited, but there are cultural and biological practices that, when combined and properly timed, can be effective in controlling Canada Thistle in these scenarios.

The following links should provide a good foundation of knowledge on the species and the management practices that show promise for its control in sustainable and organic farming systems.

Click here to download Canada Thistle Biology: Knowing Your Enemy by Abram Bicksler, John Masiunas and Dan Anderson, University of Illinois. Other resources from Drs. Masiunas and Bicksler include, Canada thistle management with cover crops and mowing 2006 and Canada Thistle Management Strategies for Sustainable and Organic Farming Systems.

Basic Information

Integrated Taxonomic Information Service
Taxonomic, nomenclature and hierarchy facts.

Illinois Natural History Survey
Basic species information with a few suggestions of management.

Missouri Plants
Beautiful close-up photos and short descriptions of Cirsium arvense.

Wisconsin Department of Natural Resources
General description of the plant, its distribution and control.



Control Practices

ATTRA -- Thistle control alternatives
A very good overview of non-chemical control practices.

UC Davis -- Element Stewardship Abstract
Very long (32 pages) and detailed paper prepared by UC Davis for The Nature Conservancy Stewardship staff.

Purdue Department of Botany, Control Practices for Canada Thistle
Brief, isolated descriptions of cultural practices. Includes herbicide recommendations.

Colorado State -- Organic Noxious Weed Management
An organic approach to control of Canada Thistle including a section on "Organic Herbicides." Also includes some comments from farmers on successes and failures.

Missouri Department of Conservation
Vegetative management guidelines for Canada Thistle.



Biological Control

Biological Control Agents for Utah Weeds: Ceutorhynchus litura, a Stem-mining Weevil of Canada Thistle
1993 Fact Sheet published by Utah State University Extension. Describes the effectiveness of Canada Thistle Stem Weevil for Canada Thistle control.

Biocontrols for Canada Thistle
Focuses on Larinus planus and Thinocyllus conicus as a biological control through reduction of seed production.

Biological Control of Weeds, Inc. Product Price List
Integrated Weed Control
Two on-line sources for biological control products.



Fire

USDA Forest Service
Impacts of fire on the ecology of Cirsium arvense.



US Federal Government Resources

USDA National Agriculture Library (NAL), National Invasive Species Information Center
Very little info on thistle itself, but a nice list of links to many, many other Federal, State and university resources.

USDA NAL Agricola References
A list of links to 161 scientific references from a search on "canada thistle" or "Cirsium arvense."

USDA NRCS
Basic ecological information. Includes photos, distribution map and many links.

US National Park Service
Plant Conservation Alliance's report on Canada Thistle.