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Look out for the Devil’s trumpet

Jimsonweed, also known as Devil’s trumpet is a highly toxic weed

According to provincial weed specialists in Alberta, jimsonweed, a highly toxic and problematic weed species, was found in three Alberta canola fields (Barrhead, Leduc and Westlock) last month. Growers are currently working with their provincial departments and the CFIA on an eradication strategy, although they are not considering it a major problem at this moment.

Jimsonweed, also known as Devil’s trumpet, is hard to miss. It grows to two metres high, towering over crops like canola. It has a reddish-purple stem, trumpet-shaped flowers, egg-shaped spiked pods and a repulsive sour odour. The leaves have irregular toothed margins that are 10 to 20 cm long. The trumpet-shaped flowers are white to purplish and have five points. The seedpod is two to five cm wide, has spines and contains 600 to 700 seeds per capsule. Once the seeds are mature, the seed capsule explodes, expelling the seeds.

Jimsonweed is more commonly found in canola crops in the United States and Eastern Canada, although it has recently been found in western Canadian fields.

“Jimsonweed became evident late in the fall when it began to tower over the crop and drew attention from farmers while swathing,” says Mike Long, communications director, Agriculture and Forestry, Alberta. “While most cases were found in canola, it also showed up in some other crops.”

Once the jimsonweed seed is mature, the seed capsule explodes, expelling 600 to 700 seeds per capsule.

Once the jimsonweed seed is mature, the seed capsule explodes, expelling 600 to 700 seeds per capsule.
photo: Nicole Kimmel, Alberta Agriculture and Forestry

Controlling jimsonweed

Since jimsonweed is a prolific seed producer, if not addressed, it could quickly spread. Early detection and eradication is needed to curb any further escalation of the problem, says Long. A routine application of broadleaf herbicide will control the plant.

Jimsonweed plants can and should be removed by hand, but take great care when doing so. Gloves and long sleeves should be worn to protect themselves from exposure to toxins. The weed should be double bagged for landfill disposal. Long notes that jimsonweed should not be composted or burned, as exposure to toxins is still highly possible. Since all parts of the plant are poisonous to humans and livestock, canola stubble shouldn’t be baled for feed where plants have been found. These practices will increase risk for poisoning in livestock feed, says Alberta Agriculture and Forestry.

Finally, Long recommends following good crop rotation practices, rotating from canola to grains and vice versa, as it will help minimize impact.

Alberta Forestry will continue to monitor occurrences in the coming spring. At that time, jimsonweed will be hard to spot, since it doesn’t mature until later in the season. But, says Long, a routine application of a broadleaf herbicide will kill the plant.

A routine application of broadleaf herbicide will control the plant.

A routine application of broadleaf herbicide will control the plant.
photo: Nicole Kimmel, Alberta Agriculture and Forestry

Health concerns unfounded

In a recent release, the Canola Council of Canada (CCC) said that while growers should continue to keep an eye out for jimsonweed, health concerns around potential toxicity in canola oil are unfounded.

“While jimsonweed itself can be poisonous, the heating process in canola oil and meal processing denatures toxic alkaloids, so there isn’t a health concern in processed canola products,” says Curtis Rempel, vice president of crop production and innovation at CCC. “It’s also important to remember that it’s the dose that makes the poison, and the high LD50 of scopolamine, the major toxic alkaloid in jimsonweed, even further supports the fact that this weed isn’t a concern in canola oil or meal.”

Alberta Agriculture and Forestry is working closely with Health Canada to gather further information. “The occurrence of the weed in our fields is minute,” he says. Generally, he continues, only one to three plants have been found in each field and the number of fields is less than a fraction of one per cent of all canola fields in the province.

“Our eradication measures look to halt any further spread of the plant,” he concludes.

Should you find jimsonweed in Alberta fields this fall, please contact Nicole Kimmel, weed specialist, Agriculture and Forestry at (780) 422-0885 or by email at [email protected].

About the author


Melanie Epp is a freelance farm writer based in Guelph, Ont.


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  • Cobra

    Just to update your information we also found devil trumpet in our field of canola in the county of Camrose…how old is your information…for a new article not very up to date Dec 29/15