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The
Control of Ragwort
This
plant appears to have alternating seasons of rampant or less
rampant growth, and it is currently spreading in the UK (2004).
Most stockmen understand that ragwort is very bad or fatal
for animals when eaten dried, but do not realise that it is
also poisonous when nibbled as a rosette in pasture. It is
dangerous in both cases, and never good for the animal concerned.
Why ? The toxins in ragwort (Pyrrolozide alkaloids) are cumulative
in all animals (and humans). They gradually destroy the liver,
so that a small dose towards the middle of a life, can turn
out to be be the fatal one. A horse only needs 1kg.of this
plant to kill it, and contrary to commonly quoted opinion,
sheep are also affected by nibbling the rosettes (although
they are mostly slaughtered before it kills them).
Rosettes & mature plants need to be removed from pasture,
after pulling,cutting, foraging, or spraying. Lazy Dog gangs
remove the complete plants from the ground, before tipping
them into trailers, ready for burning, burying, or composting.
All these operations must be done away from watercourses or
animals, and are part of the job.
The application of RIP
1. Using a new shortened version of the Lazy Dog, our gangs
aim to remove the plants as rosettes, during the Autumn &
Spring. Summer clearance work is considered to be a 'follow-up'
to this initial effort, which is carried out when the ground
is moist, the weather cool, and the burden of other jobs,
less pressing.
2. Rosette clearance requires the workforce to make full use
of a L-D tool, by getting out of the habit of bending. A collecting
bag is carried on one shoulder, and the uprooted plants are
either tipped in piles for later collection, or put directly
into a smaller trailer.
3. We mostly use the small fork (N07), because plants stick
to it while we lift them to waist height.The 'sheeps foot
nose'(N01b), can also be useful where occasional rosettes
appears among a majority of docks & thistles (e.g. in
field margins in countryside stewardship). NO1b is also useful
in dry conditions, encountered during the 'follow-up' in Summer.
A specialist zigzag rake (that we make), can be useful for
raking out massed seedling rosettes in winter.
4. After grubbing out a plant, we try to 'heal in' the larger
divots, to shield any lurking seed-bank from light. Trials
in Yorkshire suggest that this is much less of a problem than
is often suggested, especially when stock are removed.
5. We wear gloves at all times, because it's known that the
poisonous alkaloids enter the bloodstream via the skin, especially
in hot weather (see Dr Derek Knottenbelt, Liverpool Veterinary
Research).
Some management suggestions
1. Tightly stocked winter grazing (especially by heavy animals)
is asking for trouble on soils that are known to contain a
ragwort seed-bank. There is no point in expensively clearing
a site, and then allowing heavy or uncontrolled grazing. After
clearing any badly infested site (which has previously been
paddled or overgrazed), management must ensure that the turf
is allowed to thicken up & repair. In an ideal world all
grazing should be replaced by mechanical topping for two growing
seasons.
2. If grazing is continued, it should be kept very light.
Cull sheep could perhaps be used to fulfill this role, and
areas where grazing is habitually concentrated, should be
regularly fenced off, using easily moved electric systems.
If animals have to be overwintered on the site, they must
be confined to a restricted area.
3. The installation of a moveable water systems (to prevent
concentrations of heavy hoof marks in the same area), is also
be advisable.
4. When mowing hay, the view from a tractor is ideal for spotting
flowering plants growing under the grass canopy, especially
when the meadow has been winter grazed. Drivers must be informed
and asked to stop and pull these plants.
Our experience of 'RIP' and using the ' Lazy Dog' on Ragwort
1. One of the advantages of 'RIP' is that managers walk their
fields to remove more common weeds like thistles or docks,
and will often come across isolated and unexpected ragwort
rosettes, while doing this work.
2. Our handwork is skilled, so that the efficiency of operators
increases with practice. Skilled operators should have no
problem undercutting quotations from operators of spot-spray
techniques.
3. In 2001, our gangs were able to work continuously through
a month of 7 hr days. In this time they lifted plants from
two badly infested sites of 50 and 120 acres.
4. The cooler / moister conditions of Autumn / Spring make
rosette removal much easier, and it is possible to remove
a good 90% of the annual crop in this way. It is unusual for
landowners to consider ragwort control at these times of year,
and we consider this to be a mistake. The plant is much more
difficult to remove in its' entirety once the land is sun-baked.
Vigorous sections of the white root mass are often left in
the ground by traditional late season pulling. In moist earth
conditions this is far less likely to be a problem.
Mechanical control
Mowing & raking can be used as an emergency form of control,
so long as the work is timed so that the maturing plant does
not shed seed.
Sometimes the use of a forage harvester is quicker and simpler,
although operators have to be wary of the fumes from the chopped
plants (do this on a draughty day)
Chemicals
When the rosette infestation is up to 250 + plants to 25sq.
metres (say), a front mounted deep-pile weed wiping carpet
or brush soaked in Glysophate (or MCPA & 24D mixed), may
be an advisable way forward. Tests of this method are ongoing,
along with use of the 'eco- chemical' (Barrier H). The latter
may become a help with young rosettes, if it can reliably
kill them in-situ, but (we think) that the amount of chemical
used to completely cover the foliage of plants will. It also
needs spot-application, dry weather, and approval from English
Nature on SSSIs. Given a choice between using chemicals and
hand-labour, some land-managers are now opting for the latter,
because of costs.
When spraying or weed-wiping is being considered, expenses
other than the already considerable chemical costs, must be
budgeted for.
1. The purchase & maintenance costs of knap-sack, boom
sprayer or weedwiper.
2. The costs of time spent mixing and preparing the chemicals
or dealing with health & safety protection.
3. The costs of delays caused by the weather and problems
created by the need for animal exclusion.
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