Common in fields, cultivated and waste areas,and roadsides.
The toxic principle of Tansy mustard is not known. The plant is most often eaten when it is young and succulent, and it is at this stage that it is most toxic. The toxicity of the plant varies from year to year.
The neurological signs seen with tansy mustard poisoning are suggestive of sulfate poisoning.
Annual or biennial weed growing up to 3 feet in height, and branching above. Leaves alternate, hairy, 2 or 3 times pinnately compound, each segment very narrow and linear. The flowers are produced terminally on the branches in slender racemes, each flower being small (1-2mm), yellow to green in color. The seed pods are slender, cylindrical, less than 1 cm. long, ascending, with 2 compartments, each with a row of seeds.
Very similar to flixweed (D. sophia) except that the seed pods are 1-2 cm long.
Difficulty eating because the tongue appears paralysed.
Most animals will recover if removed from the tansy mustard or flixweed. Severely affected animals need symptomatic treatment including water and electrolytes via stomach tube. large doses of thiamin may help resolve the blindness.
Blindness, head-pressing is seen in some animals.
Severe photosensitization occurs in cattle grazing Flixweed and tansy mustard in early Spring.
In cattle with photosensitization, the liver enzymes are elevated indicative of a toxic hepatopathy.
Tansy mustard is common in alfalfa fields, and can therefore comprise a significant portion of the first-cutting alfalfa hay. Flixweed and tansy mustard are not nutritious, and thus devalue alfalfa hay they contaminate.
Tansy mustard is easily controlled with appropriate herbicides.