Stinkweed-Thlaspi arvense L.-Poisonous plant

Stinkweed

Other names:

Field Penny-cress, Bai Jiang Cao.

General poisoning notes:

Stinkweed (Thlapsi arvense) is a naturalized herb found in fields and waste places across Canada. The plant contains sufficient quantities of glucosinolates to be toxic. During dry periods, cattle in western Canada have ingested hay containing high quantities of stinkweed. Poisoning, death and abortion occurred (Smith and Crowe 1987). See Brassica oleracea for additional notes on glucosinolate poisoning.

Description:

Plant height: 10-50 cm tall; Growth habit: erect annual; Stems: simple to freely branched, leafy, hairless; Leaves: mostly alternate, oblanceolate, 2-6 cm long, the lower strongly wavy-margined to almost lobed, with larger end lobe, narrowed to a short stalk. Leaves farther up becoming stalkless, with ear-shaped lobes at base. Basal leaves few, withering by flowering time; Flowers: white, in open clusters on branches, with 4 petals 3-4 mm long and sepals 1.5-2.2 mm long; Flowering time: May-August; Fruits: pods strongly flattened, oval or heart-shaped, shallowly notched, 10-17 mm long, with winged edge all around, the notch 1.5-2.5 mm deep. Stalks slender, spreading to upcurved, 7-15 mm long. Style almost lacking, 0.1-0.2 mm long. Seeds about 2 mm long, not edged, wrinkled lengthwise.

Nomenclature:

Scientific Name: Thlaspi arvense L.

Vernacular name(s): stinkweed

Scientific family name: Cruciferae

Vernacular family name: mustard

Geographic Information

Common weed on disturbed ground in all parts of MT.
Introduced from Europe, now spread across N. America.

Canada: Alberta, British Columbia, Labrador, Manitoba, New Brunswick, Northwest Territories, Nova Scotia, Ontario, Prince Edward Island, Quebec, Saskatchewan, Yukon Territory.

Toxic parts:

Leaves, seeds.

Notes on Toxic plant chemicals:

Tests of stinkweed showed that the allylthiocyanate (a glucosinolate) content is sufficient to cause sickness and death in cattle; fatalities occurred at about 65 mg/kg of body weight. The amount of this chemical varies with the stage of maturity of the plant; the highest amount is in the seeds (Smith and Crowe 1987, Majak et al. 1991).

Toxic plant chemicals:

Glucosinolates.

Chemical diagram(s) are courtesy of Ruth McDiarmid, Biochemistry Technician, Kamloops Range Station, Agriculture and Agri-Food Canada, Kamploops, British Columbia, Canada.

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Cattle

General symptoms of poisoning:

Abortion, colic, death, skin, peeling of.

Notes on poisoning:

Cattle that ingested hay containing between 25-100% stinkweed were colicky and some abortions occurred. Necropsy of cows revealed revealed massive submucosal edema of the wall of forestomachs, particularly in the rumen. Lowering the rumen pH to 5 reportedly stops the allylthiocyanate from forming. However, more recent work found that lower pH did not significantly affect the liberation of allylthiocyanate. Administering large doses of piperazine (110 mg/kg) to rapidly reduce the concentration of toxin has been suggested. Ensiling hay containing stinkweed apparently prevented liberation of allylthiocyanate (Smith and Crowe 1987). Yield of the chemical is a function of the diet, with alfalfa herbage allowing the lowest release quantity (30%) and alfalfa hay the highest yield (72%) (Majak et al. 1991).