RUMINATIONS
By Kate Ayers and
Mike Cowbrough
[
HOW DO I CONTROL
TANSY RAGWORT?
Beware this alkaloid-based toxin, which is poisonous to livestock and can cause liver damage
T
ansy ragwort is a noxious weed
most often found in pastures and
hayfields in eastern, central and
southwestern Ontario. It is a biennial
or short-lived perennial that reproduces
through seeds and roots. Tansy is poisonous to livestock and can cause liver damage. Symptoms that may occur after plant
consumption include weakness, high
temperature, lack of muscle co-ordination
during movement and yellow mucous
membranes. Since there is no known antidote for this alkaloid-based toxin, removal of tansy ragwort in pasture and forage
crops would be the best way to minimize
any risk to livestock poisoning.
In Eastern Canada, there are four herbicides that can be applied to grass pastures
and list tansy ragwort on their labels as being controlled: Banvel II (dicamba), 2,4-D
Amine 600, Milestone (aminopyralid) and
Restore II (aminopyralid/2,4-D). It is unclear, from reading each product’s label,
which herbicide would most effectively
manage tansy ragwort. A trial was conducted
in 2015 at the Arkell Research Station at the
University of Guelph to evaluate the performance of each herbicide and identify effective management options producers could
use to control this weed on their farms.
At the time of application, the majority
of the plants were 15 centimetres tall and
10 to 20 cm in diameter as shown in Figures 1 and 2. The 2015 experiment found
Milestone was the most effective herbicide for controlling tansy ragwort while
the other three labelled herbicides did not
FIGURES 1 and 2. Tansy ragwort
size at time of application (Late
May 2015). The majority of the
plants were 15 centimetres tall and
10 to 20 cm in diameter.
38
APRIL 2016 | MILKPRODUCER
WWW.MILKPRODUCER.CA