By Sarah Sommerfeld, PAg, Regional Forage Specialist
Weed infestations are a cause for increasing concern, and the need for action to contain and control them is real. Because these weeds are often perennial and hard to control, the cost of control can increase exponentially as the infestation increases in size and severity. In forage stands, the loss of forage production from desirable plants results in less feed and forage for livestock use.
Leafy spurge, which is considered a noxious weed underThe Saskatchewan Weed Control Act, is extremely difficult to control and eradicate from a local area. The Saskatchewan Weed Control Act lists weeds as Prohibited, Noxious and Nuisance. Noxious weeds are weeds that are established in Saskatchewan beyond practical eradication, but are still spreading into non-infested areas. Noxious weeds are a threat to both the environment and its ecosystem functions, and to the productivity and profitability of the agriculture industry.
The leafy spurge plant has an aggressive deep, creeping root system that can send its roots eight meters (26 feet) down and can spread up to four and a half meters (15 feet) per year. Leafy spurge also reproduces and spreads by seed production, with each flowering stem producing, on average, up to 140 seeds. The seed capsules can shoot seeds up to five meters (16 feet) from the parent plant and can remain viable in the soil for up to eight years.
The local economic impact of a leafy spurge invasion can be measured through the loss of desirable vegetation, as the plant can invade rangeland and reduce its productivity for both livestock grazing and wildlife. When the leafy spurge plant population density exceeds 80 stems per square meter, rangeland can be qualified as unusable or wasteland. As a leafy spurge infestation grows in size, it can also create a physical barrier that impedes animal movement to new grazing areas.
There are a number of control methods for managing leafy spurge. Often the implementation of multiple control methods is the best defence against the spread of this aggressive plant. Grazing, particularly with sheep or goats, can be an effective control against leafy spurge. Animals can be used in environmentally sensitive areas or rough terrain where other control measures, such as herbicides, cannot be applied. Over time, grazing weakens the plant; this can be used in combination with other control methods, such as herbicides, to increase effectiveness.
Leafy spurge beetles are a biological control option that can be used with relative success. Over time, and with proper beetle management, good results of leafy spurge containment and control can be achieved. It is important to remember that leafy spurge beetles are a long-term control commitment.