Bracken (Pteridium aquilinum (L.) Kuhn) is often an unwelcome plant that has
spread into many of the upland areas of Wales, including the Senni Valley. It is
an invasive weed with a detrimental effect on ecosystems. It limits animal and
human access, smothers other plants, reduces grazing and may have harmful seeds,
but it also has some benefits in certain locations see Bayer
Crop Science and Soper D. (1996) Bracken: an interdisciplinary issue. Pesticide Outlook 7: 16–20. It is difficult to eradicate and control, but this can be attempted by
cutting or by chemical
treatment. Micron sell a battery-driven hand-held sprayer
with backpack, for treating small areas of bracken with Asulox.
Larger areas can be sprayed from a quad bike. Helicopter
spraying is useful for inaccessible or large areas. Spraying is
usually done in August. There are legal and environmental issues to be
considered before using chemical sprays to destroy bracken, as they are toxic to
other ferns, fish and mosses and their use is regulated. After bracken is
killed, steps have to be taken to prevent recurrence. For this reason, a
detailed and long-term plan for bracken control is necessary.
Asulam [methyl (4-aminophenyl sulfonyl) carbamate] is the systemic herbicide
used most often, in many parts of the world, to kill and control the spread of
bracken . It is applied as the water-soluble sodium salt Asulox. It has been
approved for large-scale aerial use since 1974. The field application rate is
4400 gai (grams active ingredient) ha–1, equivalent to approx. 100 gai l–1 for
aerial spraying. Application with a wetting agent is recommended. These include Actipron.