Ragwort (Jacobaea vulgaris, formerly Senecio jacobaea) on
Greenham and Crookham Commons

Ragwort grows widely across the commons. Populations naturally tend to be greatest in the open, sparsely vegetated or grassed areas. However, scattered individual plants can in some years be found in almost any part of the site. The population varies greatly from year to year.

Ragwort contains toxins which can have debilitating or fatal consequences, if eaten by horses and other grazing animals. It is less likely to be rejected by livestock if dried, so contamination of forage (hay, haylage and silage) is a particular problem. Humans may be at risk from ragwort poisoning through direct contact (e.g. hand pulling) or the consumption of contaminated food.

Under the Weeds Act 1959 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.

Two risks will be monitored and, if necessary, mitigated:

• The animal welfare risk, of ponies or cattle ingesting ragwort.
• The obligation (under legislation and in the interests of being a good neighbour) to prevent the spread of ragwort to neighbouring land which may be used for grazing or hay production.

The ecological value of ragwort is well recognised. The cinnabar moth (Tyria jacobaeae) occurs on the commons. As a species "of principal importance for the purpose of conserving biodiversity" the Natural Environment and Rural Communities Act 2006 requires public bodies to consider it when performing their functions with a view to conserving biodiversity [1]. One hoverfly and four beetle species with a high dependency on ragwort are recorded in the two 10 km squares which encompass the commons [1, 2]. Two of the beetles are designated nationally scarce or nationally notable.

There is, therefore, no intention to implement a blanket control policy unless there is evidence, or a strong likelihood, of risk translating to actual harm.

There is no historical evidence that livestock on the commons habitually eat ragwort. General opinion is that stock avoid it as long as there is alternative forage. However, a long hot dry summer can result in the grass and other plants shrivelling, leaving ragwort as one of the few plants with any green left in it. This presents a risk that livestock will resort to eating it. Also, in such conditions there may be a microclimate with a little extra dampness right beneath the rosettes of ragwort leaves, supporting a few blades of still-green grass. Cattle may accidentally consume ragwort when trying to get at these [3].

Herbicide control should not be used on ragwort plants which have already developed the central flower spike, because the dead plants lose their unpalatable taste and this would increase the risk of ingestion. Hand-pulling or levering plants out has been tried in the past, but soil conditions on the common (especially in dry conditions described above) make these control methods almost impossible to use effectively. In such conditions the best control is to remove some or all of the livestock.

The overall approach to managing ragwort is therefore:

• Inspect high and medium-risk compartments each spring or early summer when plants are at the rosette stage (i.e. before it is too late for herbicide control).
• In compartments and subcompartments which adjoin neighbouring pasture land, control to prevent seeding across the boundaries. Plants nearest the boundary are highest priority. If practicable, control should extend 50 to 100 m from boundaries [4].
• In other areas, if the spring population suggests a significant likelihood of ingestion by livestock later in the year...
  • Consider extending herbicide control to areas favoured by the livestock
  • Extend monitoring throughout the summer
  • If stock are suspected to be eating ragwort, but (e.g.) TB movement restrictions prevent them being taken off site, consider cut-and-collect mowing to remove flowering spikes.
• Dispose of all arisings of, or which may include, cut ragwort where they are inaccessible to livestock.

References

[1] Ruth Laybourn, Debbie Kessell, Naomi Jones, Simon Conyers, Caroline Hallam, Nigel Boatman, 2013. Review of evidence concerning ragwort impacts, ecology and control options. Food and Environment Research Agency

[2] National Biodiversity Network: NBN Gateway, hectads SU46 &SU56 (accessed 09 Mar 2015):

• Hoverfly, Cheilosia bergenstammi: SU46 & SU56
• Beetle (nationally scarce), Longitarsus dorsalis: SU46
• Beetle (nationally scarce), Longitarsus ganglbaueri: SU46
• Beetle, Longitarsus gracilis: SU46
• Beetle, Longitarsus jacobaeae: SU46
• Moth (BAP priority species), Tyria jacobaeae: SU46 & SU56

[3] C Austin, Greenham & Crookham Commons Commission meeting 17 Feb 2015

[4] DEFRA, 2004. Code of Practice on How to Prevent the Spread of Ragwort

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Ragwort risk assessment by subcompartment

Whether or not each area is grazed, and how close it is to adjoining land which may be used for hay or grazing, varies very little or not at all from year to year. Relative susceptibility to colonisation by ragwort (for example vegetation type, amount of open ground, tree cover) also shows very little change from year to year (but will be reviewed if, for example, large areas of tree or scrub cover are removed). A breakdown by compartment and subcompartment is shown below.

Table 1: Risk factors likely to remain constant for each subcompartment

Grazing stock: cattle/ponies/pigs = 2, sheep/goats = 1, no grazing = 0
Proximity to adjoining grazing land: <50 m = 2, 50 to 100 m = 1, >100 m = 0
Ragwort susceptibilty (soil conditions, vegetation, tree cover): high = 2, medium = 1, low = 0

Inspection frequency (derived from total risk score):
0 = Never, only if passing through or if highlighted by a third party, 1-3 = Biennially, 4-6 = Annually

Comp.	Subcomp.	ha	Locale	Grazing stock	Proximity to grazing land	Ragwort susceptibility	Total	Inspection frequency
01	01A	4.1	Near Pyle Hill gate	2	2	1	5	A
	01B	10.7	End of runway	2	2	2	6	A
	01C	9.6	Sandleford Heath	2	1	2	5	A
	01D	9.8	Sandleford Woods	2	2		4	A
02	02A	11.1	Brackenhurst Heath	2		1	3	B
	02B	6.8	Peckmoor Copse	2			2	B
03	03A	7.6	Aldernbridge Gully	2			2	B
	03B	11.9	Aldernbridge/Ballshill Heath	2		1	3	B
	03C	7.3	Ballshill Gully, Handpost Gully & Peaked Hill	2			2	B
	03D	3.8	Adjacent to east side of GAMA site	2			2	B
	03E	10.2	NW of fire plane area	2		2	4	A
04	04A	4.6	Clarke's Gully		2		2	B
	04B	9.2	Bishops Green Heath		2		2	B
	04C	7.2	East of Bishops Green Road					N
05	05A	8.4	Martindale		2		2	B
	05B	1.4	South of Thornford Road near A339 junction		2		2	B
	05C	9.6	Heads Hill & Goldfinch Bottom	2			2	B
	05D	8.7	Brushwood Gully	2	2		4	A
	05E	0.4	South of Thornford Road		2		2	B
06	06A	18.6	Crookham Common east of Old Thornford Road			1	1	B
	06B	3.9	Thornford Gully					N
07	07A	2.4	North of Crookham Road (w)		2		2	B
	07B	7.4	North of Crookham Road (e of 7A)		2		2	B
	07C	1.3	North of Crookham Road (e of 7B)					N
	07D	12.6	South of Crookham Road		2		2	B
08	08A	12.0		2		2	4	A
	08B	4.9		2		2	4	A
	08C	8.5		2		2	4	A
09	09	19.4	Northeast "lozenge" of former runway/taxiway area	2		2	4	A
10	10	19.4	Southeast "lozenge" of former runway/taxiway area	2		2	4	A
11	11	20.6	Northwest "lozenge" of former runway/taxiway area	2		2	4	A
12	12	19.6	Southwest "lozenge" of former runway/taxiway area	2		2	4	A
13	13	7.0	Area to the south of the estern cattle grid on BBR	2		2	4	A
14	14	19.5	Main car park, control tower and adjacent area	2		2	4	A
15	15	7.6	Northwestern areas of Greenham Common	2		2	4	A
16	16	77.5	Former runways and subsidiary areas	2		2	4	A
17	17A	1.0	Pigeons Farm Road					N
	17B	9.7	Approach to Bowdown Woods	2		1	3	B
	17C	1.7		2		1	3	B
	17D	5.1		2		1	3	B
	17E	0.7						N
	17F	0.3	Entrance to Pigeons Farm track					N
	17G	1.1	East of Crookham Golf Club					N
	17H	0.1			2	1	3	B
18	18	31.0	Crookham Pools or relandscaped area	2	2	2	6	A

The relatively unchanging risks in each subcompartment have been used to determine the inspection frquencies in the rightmost column of table 1 above. Inspections, at the frequencies shown, will be carried out to quantify risks which tend to vary from year to year with the naturally volatile ragwort population and (for instance) the availability of other forage due to weather conditions and grazing numbers. Subcompartments will be scored using table 2, below. If the score is 5 or above then ragwort management will take place in that subcompartment using the methods outlined. This policy will be adhered to wherever possible and practical. If, however, there are overriding reasons to increase or decrease ragwort management then these will be taken into consideration.

Table 2: Risk factors to be assessed periodically for each subcompartment

Factor	High = 2	Medium = 1	Low = 0	Score
Density of plants	> 10 plants per m2	2 - 10 plants per m2	< 2 plants per m2
How much alternative forage is available?	Not much, the site is heavily grazed	Enough at present, but heavy grazing might reduce availability	Plenty of forage available
Will a hay cut be taken?	Yes, a hay cut will be done where the ragwort is	No, but it might be cut the following year	No, this area will never be cut for hay
Is the extent of ragwort changing?	Extent is increasing	Extent is naturally constant	Extent is naturally decreasing
Are the livestock exposed to ragwort for an extended period?	Yes, they will be exposed to ragwort over a number of years	Livestock may be exposed to ragwort repeatedly during their life	Livestock are unlikely to be exposed to ragwort again

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