Technical
“
Ragwort at the rosette stage, the ideal time for control with herbicides
when controlling Ragwort by whatever method. Ragwort is most commonly found on
neglected or overgrazed pasture, particularly on light land, but it is increasingly found invading all types of pasture. The primary source of contamination is seed spread on the wind from uncontrolled plants on neighbouring land. Once established, the ragwort is naturally a biennial plant forming a rosette of leaves close to the ground in its first year, running to seed the following June-October and then dying. However, cutting or incomplete pulling can cause the perennation of the plant such that it branches and becomes enlarged and emerges for many years. Seed production is prolific and plants cut
in flower will still produce viable seed. Going into battle
A dense grass sward can prevent a serious invasion by suppressing the seedlings.
On pasture land, mixed grazing regimes,
especially with horses being selective grazers, are often recommended. Sheep will eat young shoots in the spring and can tolerate a certain amount of the alkaloid. This can help to control the weed, but great care is needed as even sheep have been killed by it. Cutting or hand-pulling after rain at the
flower bud stage is an alternative method. Foliage must be removed or burnt before stock return to the field. Whilst this prevents seed return, it often
has no other benefits, as a fragment of root left in the ground will regenerate into a new plant. Always wear gloves when handling plants,
even when they are dead as the poison may enter the bloodstream through skin.
Choose your weapons
Herbicides: Herbicide-treated plants become more palatable as they die back and, as
ragwort is poisonous, dying plants must be removed from the field or stock excluded until the plants have completely degenerated, (at least four weeks). Selective herbicides like MCPA or 2,4 D
can be used to control Ragwort before the flower bud is formed. Grass is unaffected, but stock must be excluded at a crucial time of year for grazing and, if the plants are still at the rosette stage, it is not practical to remove them to allow stock to return to the field sooner than four weeks. Use of these hormone-type weedkillers is often not advised in environmentally sensitive areas or near watercourses.
Control with Roundup Pro Bio and Roundup Pro Biactive 450: Roundup Pro Bio and Roundup Pro Biactive 450 will kill ragwort, but also kill grass. Both products may be used to effectively control and eradicate Ragwort in three ways:
1) As a spot treatment with a carefully
Dying plants must be removed from the field or stock excluded until the plants have completely degenerated
”
Ragwort five days after spraying, with plants just showing some yellowing in the centre. Interestingly, this picture shows two perennating plants with big roots and multiple rosettes - the result of pulling over several years.
PC JUNE/JULY 2014 I 135
Ragwort is poisonous to cattle and horses as a growing plant when conserved in hay or silage, or when dying after cutting or spraying
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