Devil’s trumpet makes headlines on Prairie farms

While swathing last summer, canola growers from Barrhead, Leduc and Westlock Counties in north-central Alberta started to notice a strange weed standing high above their crops like trees.

One producer’s wife, unfamiliar with the alien plant, pulled just one out from the edge of their field and immediately began to have an allergic reaction, which quickly turned into anaphylactic shock that had her rushed to hospital. Subsequent testing of the plants revealed that devil’s trumpet had arrived in Western Canada.

“We first heard about devil’s trumpet from the producer whose wife became very ill,” says Robyn Gerrard, business agronomist at Parkland Fertilizers. “It turns out that devil’s trumpet has been turning up more and more often and local officials were trying to contain and isolate the problem.”

Devil’s trumpet (Datura stramonium) – also known as jimson weed, devil’s snare, or thornapple – is a plant of the nightshade family and is well known for its high toxicity. All parts of the devil’s trumpet plant are poisonous and even small amounts of this noxious weed can be dangerous and possibly fatal to ingest, inhale or even handle.

Just how these toxic plants arrived into Alberta is still unknown, and under investigation by the Canadian Food Inspection Agency and Alberta Agriculture and Forestry. A contaminated seed lot is thought to be a likely suspect.

“The speculation is that this weed came in from seed grown in a different country,” says Gerrard. “But we’ve also been told that devil’s trumpet might have been lying dormant in the soil for years, like many other weed seeds are capable of doing. What we do know for certain is that we need to be getting a weed this harmful out of the field before it spreads and becomes a serious problem for producers.”

“At the time we reported the devil’s trumpet to the Alberta weed inspector, we were told that they were already aware of a few cases around the Edmonton area,” says Gerrard. “They wanted us to turn all the weeds over to them so that they could be documented and tracked in the case of a larger outbreak.”

The appearance of the weed could possibly be attributed to warmer-than-usual temperatures. “The increasing shift to row-crops in our warmest growing regions may allow this weed to become more of a consistent issue,” says Jeanette Gaultier, Ph.D., weed specialist at Manitoba Agriculture, Food and Rural Development (MAFRD). “Devil’s trumpet needs very particular environmental and agronomic conditions to become established,” she says. “For the most part, it does not compete well with our cool season crops.”

MAFRD received reports of devil’s trumpet from a small number of producers and agronomists, many of whom had already identified the weed but sought confirmation and further advice on how to contain the problem.

Handle with Care

Prevention is the best medicine when it comes to protecting an operation from devil’s trumpet. There are a few herbicides used in the U.S. that have proven successful in controlling devil’s trumpet in corn and soybean crops, but whether or not these herbicides are effective when used alongside canola, wheat or barley is as yet untested.

It is assumed, however, that a few common herbicides including glyphosate, glufosinate and various group 2s, 4s, 6s, 14s and 27s should provide some control of this weed where it is found. If it survives the herbicide stage, early detection and removal of devil’s trumpet is key to stopping the spread of the weed.

Agronomists and agri-retailers working with producers can help to identify the problem when and if it appears. It is a tall plant when mature, standing around five feet high with large, lobed leaves alternating up its thick stem. The large white, purple or pink flowers are, not surprisingly, trumpet-shaped. Devil’s trumpet will also be identified by its prickly seed pods – similar to bur cucumber but spinier – which contain hundreds of dark, canola-sized seeds per pod. When the plant matures, the pods crack open and eject scores of seeds, resulting in more problems in future seasons. It is vital that devil’s trumpet with developed seed pods be hand-pulled from fields before the swathing season begins.

Removal of devil’s trumpet from fields also demands extra precaution, because of the plant’s toxicity. Long-sleeved shirts and gloves are always recommended when handling devil’s trumpet. Once pulled, the entire weed needs to be carefully placed into a plastic garbage bag while double-checking to confirm that all parts of the plant have been collected, particularly any seed pods which may have fallen off as it was pulled.

Provincial weed specialists have asked anyone who thinks they have found devil’s trumpet to report the incident. The provincial specialist can aid in identifying the plant and discuss further containment and eradication strategies. Experts strongly recommend that the weed be buried at a landfill once bagged. Burning devil’s trumpet is not suggested because of the potential of toxic fumes being released into the air, resulting in secondary poisoning.

Producers can also be proactive in controlling this weed through the use of a robust crop rotation that includes competitive crops, such as cereals and canola – plants that may simply out-compete devil’s trumpet in the field.

Although provincial specialists say that outbreaks are as yet an uncommon occurrence, Canadian farmers, agronomists and agri-retailers should remain vigilant in looking out for the weed. Left unchecked, devil’s trumpet could become a serious problem.

Share your Solution

Have you solved a challenge for one of your customers? Email This email address is being protected from spambots. You need JavaScript enabled to view it. to share your story with other agri-retailers.