![Canada Thistle](https://images1.farms.com/farms-production-images/Portals/0/Images/Tractor/894.jpg)
This weed, also known as Creeping Thistle, is very competitive and can cause extensive yield losses in barley, canola, wheat and other crops.
A density of 20 weed shoots per 10 square feet (one square metre) can reduce canola yields by 24 percent. Similar densities in wheat can reduce crop yields by up to 38 percent.