Common Ragwort (Senecio jacobaea, hereafter referred to as ragwort) contains pyrrolizidine alkaloids which are poisonous to horses, other farm animals such as sheep and cattle and also to wild animals such as hare and deer. It is important for horse owners and horse pasture owners to recognise and control this potentially fatal plant.
Unfortunately, some horse-keepers do not control ragwort growth and spread as they do not expect their horses to eat the plant and probably don't appreciate the reality of the suffering their animals could be caused. It is true that ragwort does have a bitter taste which often deters horses from eating it. However, if grass becomes sparse (e.g. following a period of hot dry weather) horses may resort to eating plants they wouldn't normally eat, including ragwort if it is present. Some horses develop a liking for the bitter taste and may choose to eat it even when there is sufficient palatable grass available to graze on. Uncontrolled ragwort left growing in and around horse pastures exposes horses and ponies to poisoning and possibly death, and the infestation will increase each year as plants set seed. Read on to find out more about the plant and how it can be controlled.
Ragwort is one of the most frequent causes of plant poisoning of livestock in Britain.
Equines and bovines are more susceptible to ragwort poisoning than other livestock.
Young animals are more at risk than mature animals.
Ragwort is also harmful to humans. It can enter the bloodstream through the skin: protective clothing MUST be worn when handling the plant.
The plant favours well-drained soils but will grow in most ground conditions. Activities (e.g. poaching) which lead to a loss of ground cover and soil disturbance encourage ragwort growth.
Ragwort is normally a biennial, present as a rosette close to the ground in spring of its first year then growing upwards and flowering during the summer of its second year. However, cutting or topping ragwort may alter the plant's lifecycle and result in it being present as a perennial.
Overgrazed land provides ideal conditions for ragwort growth and spread. Due to the lack of grass cover, the plants are more likely to be eaten.
Well-managed pasture, with a dense grass sward provides less of an opportunity for undesirable weeds to invade.
Each plant can produce up to 150,000 seeds with a 70% germination rate.
Ragwort seeds can be dormant in the soil for up to 20 years. This explains why the odd plant may appear - despite good pasture management - where weeds are otherwise under control.
Fragments of root left behind in the soil when the plant is removed can regrow.
Ragwort poisoning can occur at any time of year, so remain vigilant year-round.
Ragwort acts as a cumulative poison, eventually destroying the liver. A small intake of ragwort over a long period can be just as damaging as a larger intake on a single occasion.
Little can be done for an animal once the clinical symptoms appear.
The toxins in ragwort are not destroyed by cutting, pulling, digging up, spraying or drying.
Ragwort becomes much more palatable following cutting or treatment. As the plants wilt and dry, the bitter taste is lost. Horses lose the ability to detect it and are therefore likely to eat it readily. Never allow animals access to plants which have been treated or removed from pasture.
Always examine dried forage for poisonous plants: dried grass, hay and haylage may potentially contain ragwort. It is not always easy to recognise fragments of the plant in forage. Samples can be sent away for analysis, but the sample results will not guarantee all bales are free of ragwort. If you are able to buy locally-produced hay or haylage, you may even be able to enquire as to the method of weed control used and visit the site where it has been produced.
Common Ragwort is one of five Injurious Weeds specified in the Weeds Act 1959: Spear thistle (Cirsium vulgare); Creeping or field thistle (Cirsium arvencense); Curled dock (Rumex crispus); Broad leaved dock (Rumex obtusifolius); Common ragwort (Senecio jacobaea). This Act empowers the respective Agricultural Ministers (in Scotland, The Secretary of State) to serve notice requiring an occupier of land on which ragwort is growing to take action to prevent the weed from spreading.
The Act does not make it illegal to have any of the five injurious weeds growing on land. It is concerned with controlling the spread of the weeds to adjacent land.
The adoption of the Ragwort Control Act in November 2003 was an important step forward in the protection of equine welfare. The new Act, which amends the Weeds Act, provides added protection to horses and came into force in February 2004.
The Ragwort Control Act allowed for the production of a Code of Practice (CoP) on how to prevent the spread of Common Ragwort to land used for horses, livestock and feed and forage production. The Code can be obtained free of charge from Defra Library by telephoning 0207 2386575.
In 2005 Defra produced Guidance on the disposal options for common ragwort. This guidance is supplements the advice given in the above Code of practice and should be read in conjunction with the Code. Like the Code, it is available free of charge from Defra publications or by downloading the guidance from the Defra website.
How ragwort poisons
Toxic pyrrolizidine alkaloids are present in all parts of ragwort. Groundsel also contains the toxins, but in smaller amounts. When ragwort is eaten, the toxins are absorbed from the gastro-intestinal tract and are released in the liver. They cause cell damage and inhibit the organ's normal repair and regeneration processes. The liver is the largest organ in the horse's body and has numerous digestive, metabolic and storage functions. Clinical signs will depend on the severity of the poisoning and can vary due to the many functions of the liver. Symptoms may include: loss of weight and condition; jaundice; photosensitive dermatitis; behavioural abnormalities; a staggering gait; impaired vision; abdominal pain and convulsions. However, because the liver can maintain its functions until two-thirds of the organ has been destroyed, symptoms of poisoning may not be apparent until as much as 75% of the liver has suffered damage. By the time signs of liver failure are evident, it is unlikely that it will be possible to save the animal.
There are no simple tests currently available to specifically detect ragwort poisoning. However, clinicians at Liverpool Veterinary School have developed a blood test to detect early signs of exposure to ragwort. A pilot study showed that the test is effective at recognising changes in certain components of blood cells, which are caused by current or recent access to ragwort toxins. The test is not currently available as more funds are needed to confirm the test's accuracy and reliability.
Good year-round pasture management combined with appropriate stocking rates (based on the particular equines, land characteristics and size), will reduce the likelihood of the ground conditions arising which predispose ragwort problems. Productive grassland has a dense sward which provides little opportunity for ragwort to grow amongst the grass. However, overgrazed pasture - with reduced grass cover and possibly soil damage - encourages seeds previously dormant within the soil to germinate and provides the ideal growing space for ragwort plants to establish. Left uncontrolled, the plants will reseed and increase in number each year. It is also important to manage undergrazed pastures as these too can be subject to weed establishment. Please refer to the Grassland Management Advice Page for more information on how to manage pasture for maximum all-round benefit. Read the Project's bi-monthly Grass Tips pages to keep up to date with timely pasture management practices.
The following techniques can be used alone or in combination to reduce, control or eliminate ragwort:
Prevent infestations by carrying out good pasture management: the benefits of ragwort control methods are short lived unless the pasture is well managed, as re-infestation will inevitably result.
When ragwort is first noticed short-term measures may be necessary immediately to get rid of existing plants, followed by long-term measures and improved management to prevent re-infestation.
Control needs to be ongoing and combined with good pasture management.
Ragwort control must be effective, but efforts should be made to ensure it causes no risk to human health, animal health or the environment. Whatever method of control is used, protective clothing must be worn by any person handling ragwort (i.e. gloves, long trousers, a long sleeved top and a face mask). Skin should be washed after ragwort control has been carried out. There is anecdotal evidence that ragwort can cause liver damage in people if they handle ragwort whilst unprotected.
Is only acceptable in an emergency situation to prevent reseeding. In this situation ragwort may be cut mechanically but in order to prevent seed production and dispersal, plants must be cut before flowering begins.
Be aware that cut plants may re-flower at a later date.
Generally cutting is not a recommended method of control as: it can result in more vigorous re-growth; turns the plant from a biennial into a perennial; only presents a short-term solution and doesn't kill plants.
Never leave cut plants within reach of horses.
2. Pulling / Digging:
Hand pulling and digging are most practical when growth is over a small area or only a few plants are present across a large area. For larger or dense areas of ragwort growth, it is more practical to use a tractor-mounted mechanical puller.
Combined with good pasture management, the pulling/digging up of ragwort can be a successful way to control the plant without having to apply herbicide.
In order to avoid the risk of poisoning, ragwort should be pulled/dug up during the initial stages of growth. Ragwort is most easily removed at this time when the plant is immature (as a seedling or rosette). The task will be easiest when the ground is soft, following rainfall. As the plant matures, the roots become more established making hand-pulling more labour intensive and increasing the likelihood of root fragments being left behind in the soil. Also, as spring progresses into summer, the ground becomes baked hard and the task of pulling plants complete with their roots becomes more difficult.
As ragwort is a biennial, pulling/digging will need to be carried out for at least two years. Pulling will have to continue annually if the pasture has a history of ragwort infestation (and therefore has seeds present in the soil) or is subject to fresh seeds falling onto it.
It is important to remove as much of the root as possible as ragwort can re-generate from root fragments left behind in the soil. Rock salt (available from agricultural merchants) can be poured into holes after digging to kill any remaining roots.
Labour-saving tools are available to ease the effort involved in pulling and digging ragwort by hand. Two examples are the Lazy Dog Tool and Rag Fork.
Never leave pulled plants within reach of horses.
3. Herbicide application:
Seek the advice of a herbicide contractor with a recognised Certificate of Competence.
Always read the product label and follow the manufacturer's guidance and statutory conditions.
The method of application will depend on factors such as the size of the area to be treated, the density of infestation, land gradient and ground surface etc.
If circumstances dictate that a herbicide application is necessary, a selective herbicide should be used to reduce damage to non-target species.
Spot-treatment (with a knapsack sprayer) is preferable to blanket spraying as this allows only the ragwort (and not other beneficial species) to be targeted. Blanket treatment (using a tractor-mounted sprayer) will not only kill ragwort but will also kill other species which might be important for biodiversity. Hand held or tractor mounted weed-wipers may be used when ragwort has reached a sufficient height above the surrounding non-target vegetation and allow plants and grass below that height to remain unaffected.
When hand spraying, chemical drift will be reduced if: a guard is fixed to the sprayer; fine spray nozzles are avoided; low drift nozzles are used; spraying is avoided during unsuitable weather conditions (e.g. on very calm warm days or during strong wind).
Most herbicides work best when they are applied to plants during an active growth period. Aim to kill rosettes before they grow into flowering plants.
A second application may be required in the same year
Remember that not only do you have to follow the manufacturer's instructions on the period for which stock must be withdrawn following herbicide application, but that you must wait for plants to die, disintegrate and be cleared.
In the event of land being protected by legislation, the relevant authority should be consulted prior to any chemical applications.
Spot burners may be used to kill ragwort rosettes. However, they carry potential vegetation fire risks and are generally only suitable for use on hard surfaces and paved areas.
Biological control involves using ragwort's natural predators to damage plants and to keep the plant population under control. For example, the cinnabar moth and caterpillar feed on ragwort plants. It is difficult to maintain sufficient predator population levels, so biological control is currently not a suitable method of ragwort control for grazing land or land used for forage production.
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Ragwort remains toxic when dried but becomes increasingly palatable, so horses must never have access to cut, pulled, sprayed or otherwise treated ragwort. Please refer to the Defra Guidance on the disposal options for common ragwort for detailed information. Be aware that flowering plants may go to seed following pulling and that seeds may fall from plants which have been cut, pulled or otherwise treated. Ragwort should therefore only be moved in sealed bags or enclosed containers. There are several possible methods of disposal, and selection is likely to be based upon the amount of ragwort to be disposed of and the facilities available for disposal. Whichever option is used, it should not be carried out near watercourses, ditches or where animals have access.
Fresh ragwort does not burn well due to the moisture content and attempting to burn it will create dark smoke. Ragwort which is due to be burnt should be stored in an undercover pile or in paper bags prior to burning: paper bags allow the plants to wilt and can be burnt. Plastic sacks should not be used during wilting and must not be burnt. If there is any risk that seeds may be dispersed, then the seed heads should be cut off and placed in sealed bags. Safety precautions should be taken to ensure the fire is controlled (e.g. smoke will not blow onto nearby access routes, surrounding vegetation isn't likely to catch fire etc) and does not cause a nuisance to others.
Composting can only be carried out using a fully contained system. This involves ragwort being composted in a container where draining liquid is contained, and where weather can't affect the process. The British Standards PAS 100;2005 specification for composted materials must be met. The specification is available from the WRAP organisation, telephone 0808 1002040.
Rotting down ragwort is likely to be a more practical solution than composting is for horse-keepers. It involves using a standard composting bin with a lid to allow small quantities of ragwort to biodegrade. Adding grass cuttings on top of the fresh ragwort will help the decomposing process and some water may need to be added to keep the material moist. To help ensure ragwort seeds and roots are killed, the plants should be left for 12 months (with no new plant matter added) before the compost bin is emptied.
Other disposal methods include biomass and incineration.
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Who to contact if you are concerned about ragwort spreading onto your pasture
The occupier of land where ragwort is growing is primarily responsible for controlling the plant.
If you are concerned about ragwort spreading from nearby land onto horse grazing, Defra advise that you initially approach the land owner/occupier to request that steps are taken to prevent the weeds from spreading. Please refer to the table below for details of who to contact regarding land by Surrey's roads or railways.
If your approach is unsuccessful in resolving the problem, it should be reported to Defra using the following complaint form on the DEFRA website: Weeds Act 1959 - Complaint Form (WEED2/WEED2A). The form should be submitted to the Reading Office at: Natural England, Injurious Weeds, Customer Services, PO Box 2423, Reading, RG1 6WY. The office can also be contacted by email at: firstname.lastname@example.org or by telephone: 0300 060 1112.
On receiving a completed Complaint Form, Defra will assess the priority of the complaint. High priority is given to complaints where weeds are threatening land used for: grazing or keeping horses; agricultural activities; producing conserved forage and where the complainant has made reasonable efforts to contact the landowner or occupier where the ragwort is growing.
Contact details for reporting ragwort problems by Surrey's roads or railways:
Railway land and embankments
40 Melton Street, London, NW1 2EE
Tel: 08457 114141
Motorways and trunk roads
Highways Agency (Surrey), Areas 3 & 5, Federated House, London Road, Dorking, Surrey, Rh3 1SZ
Tel: 0300 123 5000
All other roads
Surrey County Council
View Surrey County Council's Weed Control webpage to find out how SCC controls road-side weeds. The page also has a link to the Highway Problems and Enquiries Form, which can be used to report problems.