Hadroplontus litura, or the Canada thistle stem weevil, is a biological control agent that attacks Canada thistle by larval feeding within the stem, opening the plant up for secondary damage from other organisms such as opportunistic pathogens. Its deep roots are the real issue. Researchers with Agriculture and Agri-Food Canada (AAFC) at … Biological control insects for Canada thistle are commercially available, but Canada thistle control results have been variable and the insects' impacts on native thistles have not been thoroughly tested. The best approach to Canada thistle control in cropland should include an in-crop herbicide treatment to suppress Canada thistle growth, minimize crop yield losses and prepare the thistle for a fall postharvest treatment. Last updated Nov. 5, 2003. Two years before confederation, legislation required farmers to cut the weed 1. Grazing Canada thistle with goats is a control option because goats tolerate and often prefer spiny, tough fodder that other livestock reject. Hadroplontus litura. The seeds of this broadleaf perennial can go dormant for up to 20 years 2, but only about 10% of Canada thistle is spread through seed 1. Canada thistle can displace endangered or threatened plant species. Common Name: Canada Thistle Scientific Name: Cirsium arvense (L.) Scop. Canada thistle is the only thistle in North Dakota that has become a cropland pest. To control Canada thistle, use Roundup® For Lawns 1 Ready-To-Use to spot treat plants as they appear. Additionally, no transportation, propagation, or sale of these plants is allowed. To prevent future Canada thistle invasions, routinely fertilize your lawn (4 times per year) to keep it so thick and lush that there’s simply no room for weeds. Canada thistle (Cirsium arvense) [exit DNR]. In pastures, Canada thistle is a deterrent to grazing because cattle avoid eating the spiny leaves. Canada thistle shoots are relatively easy to kill with herbicides, it's the extensive root system that makes the weed so difficult to bring under control. Tilling Canada thistle will spread the plants by root pieces, but repeated tilling A problem perennial weed in many cropping systems, Canada thistle, has consistently ranked in the top five weeds in the Canadian Prairies in relative abundance. Conservation Easement Management: The window is short for spot spraying and it can be hampered by the large areas of dead vegetation that blocks ones view of the small plants at their most vulnerable point. Canada thistle is more difficult to control manually because of its creeping root system. Virginia Tech Weed Identification Guide. In fact, Canada thistle is older than Canada itself. To optimize perennial broadleaf weed control, herbicide selection and use must be co-ordinated with crop rotations and cropping practices over the long term. Legal Status: Prohibited - Control Efforts must be made to prevent seed maturation and dispersal of plants into new areas. The greater control of Canada thistle with Tordon in these two studies may be explained by the persistence and mobility of … 2018 Information. Links for more information: Repeated mowings when the plant has tight flower buds can help decrease the number of plants. McClay, A.S. Canada thistle In: Van Driesche, R., et al., 2002, Biological Control of Invasive Plants in the Eastern United States, USDA Forest Service Publication FHTET-2002-04, 413 p [exit DNR]. Herbicide control of Canada thistle is most effective when you apply the herbicide in spring (April, May or June) or fall (September or October). Canada Thistle Control.