Common Ragwort

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Control of Common Ragwort (Senecio jacobaea) with Roundup Pro Biactive

Background

Common Ragwort, (Senecio Jacobaea), has a 1 metre stem carrying multiple yellow, daisy-like flowers and leaves of a pinnate, ragged appearance. It is poisonous to cattle and horses as a growing plant, when conserved in hay or silage or when dying after cutting or spraying. The poison is an alkaloid, which accumulates in the liver and though only small amounts may be consumed at a time, the effects may ultimately be serious, even fatal. Dead or dying plants become palatable to stock, whereas live Ragwort is not eaten, so stock exclusion is particularly important 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.

 

There is a further species known as Oxford Ragwort, (Senecio squalidus), which is thought to have escaped from the Oxford Botanic gardens in the 18th Century and is shorter than the common ragwort at only a third of a metre in height. This species tends to colonise waste ground and railway embankments.

 

Once established Common 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, persisting for many years.

Seed production is prolific and plants cut in flower will still produce viable seed.

Legal Status

Common Ragwort is scheduled as an 'injurious weed' under the 1959 Weeds Act. Under this act;

The Secretary of State for the Environment, Food and Rural Affairs can, if satisfied that injurious weeds are growing upon any land, serve a notice requiring the occupier to take action to prevent the spread of those weeds. An unreasonable failure to comply with a notice is an offence.

The Ragwort Control Act 2003 gives 'The Code of Practice on how to prevent the spread of Ragwort' evidential status in any proceedings taken under the Weeds Act 1959.  Defra can take enforcement action where Ragwort poses a high risk to horses, the production of forage or agricultural activities.

The Code of Practice places the onus of responsibility for landowners and managers including Local Authorities, railways, Highways Agency etc to have Ragwort Control Policies in place. They should assess the risk on land they own and implement control policies on any land identified as being Medium risk and take immediate action on land identified as being High risk. Failure to follow the code may be used in evidence in prosecution under the Weeds Act.

Copies of the Code of Practice can be downloaded from the DEFRA website.

NB:The Ragwort Code of Practice does not apply to any of the other species of Ragwort.

Control Methods

  • A dense sward can prevent a serious invasion by suppressing the seedlings.
  • 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.

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 4 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 Biactive

 

Roundup Pro Biactive will kill Ragwort but it also kills grass. It may be used to effectively control and eradicate Ragwort in three ways:

  1. As a spot treatment with a carefully directed knapsack sprayer fitted with a sprayer hood or guard.  There must be enough actively growing leaf above ground to absorb sufficient product to kill the underground roots. Avoid spraying whilst the stem is extending rapidly as the sap flow is against the direction of movement down to the roots and poor control may occur.  Apply from when they have produced a flowering stem but before seeds are set.  Plants in the first year rosette stage may also be spot treated but they may be hard to spot amongst taller grasses.
  2. Using a hand-held or tractor/quad bike-trailed weed wiper will allow selective control of taller plants in grass or turf.  The new generation of trailed rotary and tractor mounted weed wipers, such as the Logic Contact 2000,  C-Dax Eliminator or the Carier Rollmaster, make efficient selective application of Roundup Pro Biactive, possible over large areas.
  3. As part of a reseeding operation to establish a new grass sward. 

Rates, Timings and Water Volumes

MethodDose Rate of Roundup Pro BiactiveDose Rate of Roundup ProBiactive450Application Advice
Overall or Spot Spray 5l/ha in 80-250l water 4l/ha in 80-250l water

Spray at flowering but before seed set.  Ragwort plants can be cut or pulled 5 days after spraying, allowing grazing to recommence. Any remaining roots will die off.

Weed Wiper 1 part Roundup Pro Biactive in 2 parts water 1 part Roundup ProBiactive450 in 3 parts water Useful method when working in inaccessible areas

Spot Treatment in Knapsack Sprayer Most knapsack sprayers are supplied with a set of 4 deflector nozzles giving different swath widths but all delivering 200l/ha of water at 1 bar pressure and a walking speed of 1 metre per second.

Area SprayedRate of Roundup Pro BiactiveRate of Roundup ProBiactive450Volume of Water
50 Square Metres 25ml 20ml 1 litre
500 Square Metres 250ml 200ml 10 litres
1,000 Square Metres 500ml 400ml 20 litres