Technical
Horsetail
An attractive nuisance! H
A nuisance on golf courses and difficult to get rid of in landscaping, horsetail can be a frustrating, if not
unattractive, weed. But a combination of cultural control and judicious use of glyphosate can offer a solution, says Monsanto’s Manda Sansom
orsetail is a family of weeds not to be confused with Mare’s tail, (Hippurus vulgaris), which is an aquatic plant of an entirely different species. The Horsetail family consists of a single genus of a lower order of plants. Common Horsetail or Field Horsetail (Equisetum. Equisetum Arvense) is the most widely seen but Marsh Horsetail (Equisetum palustre) and Wood Horsetail (Equisetum sylvaticum) are also common. It is part of the division Pteridophyta which has survived since the Carboniferous age when the coal measures were laid down and can be seen fossilised in ancient rocks.
Identifying the enemy
Horsetail is a perennial with creeping, rhizomatous stems, which can penetrate two metres into the soil.
Much of the spread of the plant is vegetative via these rhizomes, but a sexual fruiting stem carrying a sporulating fruiting body emerges in the early spring to about 25cm in height. The stem is brownish white and hollow, terminating in a cone-like structure bearing sporangia on their scales.
128 PC DECEMBER/JANUARY 2014
The spores are ripe in April when the sporangia burst, liberating their spores before dying down. Spores are only able to germinate for just over two weeks and are not thought to be the main form of dispersal, though they can give rise to hybrids between the different Equisetum species.
Barren pale green, jointed vegetative stems emerge from April onwards, extending to 30-60cm in height and bearing slender, simple branches in place of leaves in whorls of up to twelve. It is these stems which are increasingly seen as a problem in waste ground, non-cropped areas and gardens.
Most species of Equisetum are poisonous to livestock by virtue of alkaloids and the enzyme Thiaminase, which destroys Vitamin B1 and causes animals to suffer from Vitamin B1 deficiency. Horsetails are usually avoided by grazing livestock, but should never be fed to livestock in hay or silage.
Going into battle
Drainage in wet areas, liming where necessary and repeated cutting of the vegetative shoots can all contribute to
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