More than 10 years after it was identified as a major weed pest in Manitoba, leafy spurge is now a much worse problem than ever.
A new survey says leafy spurge infests over three times as many acres and produces twice as much financial damage as it did in 1999, when the last survey was taken.
Officials warn the rapid spread of this noxious weed is cause for alarm.
“I would suggest to landowners, producers and people who are trying to make a living off the land, as well as people who are trying to protect what little original landscape we have left, it’s quite alarming,” said Cheryl Heming, an Invasive Species Council of Manitoba co-ordinator.
The sur vey by Brandon University’s Rural Development Institute found 1.2 million acres of leafy spurge in Manitoba. RDI estimates the total economic impact of leafy spurge in Manitoba at $40.2 million.
The last time RDI surveyed leafy spurge densities in 1999, it reported 340,000 infested acres and a $20-million impact.
The most affected places are natural areas, pastures and forage land, roadsides, rail lines and utility corridors. Nearly 40 per cent of such locations in Manitoba have at least some leafy spurge infestation. Twenty-two municipalities, many in western Manitoba, have either high or extremely high levels.
Control programs by municipalities and research projects by private organizations appear to have done little to stem the proliferation of leafy spurge throughout the province.
It’s not clear why the weed has spread so much in such a short time, despite efforts to halt it, said Wayne Digby, chair of the Leafy Spurge Stakeholders Group which commissioned the survey.
But he described leafy spurge as “a very interesting plant” which spreads easily, is very aggressive and extremely hard to kill.
Efforts to control it are often localized, unco-ordinated and underfunded, Digby said.
“I don’t think we’ve done a very good job of managing the weed and controlling it,” he said.
“Bottom line is, more resources are needed and a bet ter and more planned approach.”
The 37-page report released last month is based on data collected in 2009.
REDUCED LIVESTOCK PRODUCTION
The report derives the direct economic losses from leafy spurge by estimating the reduced carrying capacity of pastures and the costs incurred to control the weed. It also
factors in the indirect costs of reduced livestock production.
There are other costs from leafy spurge that haven’t even been explored, the report says. Those include the loss of wildlife habitat, impacts on soil and water conservation and the private costs of controlling leafy spurge on residential yards, gardens and golf courses.
Looked at from any angle, leafy spurge is a huge problem which needs more public attention, said Digby.
“We need some kind of recognition that this is a real issue that is costing us dollars,” he said. “It’s a critical situation that needs to be addressed.”
In a way, though, leafy spurge is a hidden problem because it generally is not a pest on cultivated land. The weed is more commonly found on grazing and marginal land, so it is not a major factor in lowering crop yields.
Heming, a trained biologist, said Manitoba needs a formal response plan for managing leafy spurge instead of leaving it to municipalities and weed districts. Many local jurisdictions lack the necessary resources to fully attack leafy spurge, so control efforts tend to be spotty, she said.
Since leafy spurge is so endemic, there’s little point in an all-out campaign to eliminate it. What’s needed are co-ordinated landscape management plans to contain the spread in infected areas and to clean out newly infested ones, Heming said.
“Some land is so infected, if there’s only limited resources, it’s better to put them in the areas where you can actually stop the spread.” [email protected]