Control strategy against Cyperus esculentus in Switzerland
Cyperus esculentus (Cyperaceae, EPPO List of Invasive Alien Plants) originates from subtropical regions and is widespread in Europe. The plant reproduces through small tubercules in the ground which can survive very low temperatures. The species can grow in a wide range of environments.
In Switzerland, C. esculentus has recently spread due to different factors. First, the plant is usually identified too late as in its juvenile stage it is often confused with other species. Second, as tubercules occur in the 20 cm of upper soil layer and can remain viable for 5 years, they adhere to vegetable roots, and are therefore very easily spread via harvested vegetables, machinery and shoes. Finally, the position of the leaves does not allow a good adherence of herbicides, although the control with such products may in some cases prove successful.
As there is no efficient long term control method, the following measures are recommended:
- New outbreaks should be identified and reported as early as possible and managed.
- Farmers and any staff involved in field activities should be informed about the threat of the species and be able to recognize it.
- Spread of the species from one field to another should be prevented. Vehicles should not be moved from infested fields to non-infested ones. Shoes should be cleaned. Infested fields should be mapped, and these maps should be made available. Wastes and residues from root vegetables grown in infested plots should not be moved to uninfested plots.
- Ploughing should be undertaken before C. esculentus grows to reduce tubercule formation.
- Heavily infested plots should be removed from crop rotations and treated.
It is recommended that C. esculentus be regulated and that reporting new findings and management become mandatory.
Sources
Bohren C (2014) Searching for a control strategy against yellow nutsedge (Cyperus esculentus L.). Abstract of the 4th International Symposium on Environmental Weeds and Invasive Plants, Montpellier (FR), 2014-06-19/23.
Bohren C (2013) Souchet comestible (Cyperus esculentus l.): situation actuelle en Suisse. Agroscope. Confédération Suisse. http://www.agroscope.admin.ch/publikationen/einzelpublikation/index.html?lang=fr;aid=33027;pid=33001