A red flag was waved this month concerning St. John’s Wort and fears that it could become a menace in Manitoba.
The Manitoba Weed Supervisors Association worries about the impact the nutraceutical crop could have on agricultural land. The association wants precautions to manage escapes of St. John’s Wort from cultivated plots in the province.
“If we start to get escapes and have difficulty controlling them, who’s going to bear the cost of that control?” asked Kent Shewfelt, a spokesperson for the association.
Shewfelt noted that St. John’s Wort is named on the current schedule of the Manitoba Noxious Weeds Act. There are already some isolated pockets of infestation in southeastern Manitoba, he said.
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St. John’s Wort was first detected on a farm in that region. It’s believed that a load of hay, imported from British Columbia, carried the seeds.
By the time the farmer realized he had a problem, 10 acres were infested, Shewfelt said.
Any uncontrolled spread of the plant could cost farmers productive grazing land. In forage crops, the presence of St. John’s Wort could hamper shipments of hay to other provinces and into the United States, said Shewfelt. Although seldom lethal, St. John’s Wort can prove toxic when eaten by livestock, he added.
Chemical and biological controls have limited success in controlling the plant. The most effective herbicide control has been high rates of Tordon 22K in patch treatments. However, those areas have shown regrowth of the plant within three years of treatment.
Shewfelt said the association’s greatest concern now is the potential for people to transplant St. John’s Wort throughout the pro-vince. Birds can also spread it after foraging on its seeds.
While there can be profit in growing the crop for the nutraceutical industry, Shewfelt wonders what will happen if prices for St. John’s Wort collapse. “Will those patches be controlled?”
The Manitoba Weed Supervisors Association wants economic and environmental impact studies done at the expense of those wanting to see St. John’s Wort cultivated in Manitoba.
The association also wants a stewardship agreement established that would provide money for control of the plant should future infestations occur. That money, according to the association, should also come from those expecting to reap a profit from St. John’s Wort.
As well, Manitoba weed supervisors want clarification from the province concerning their mandate and how that relates to St. John’s Wort.
Because the plant is listed as a noxious weed, supervisors appear to have a mandate to control any actively growing plants on property within their jurisdictions.
