On 17.06.2016, the research group Extension Gemüsebau of the Swiss Agroscope Institut presented several methods for combatting tiger nut sedge. One of the most effective methods among these is steaming.
Three different steaming methods were successfully tested: hood steaming, sheet steaming and pile steaming via steam conveyor in cooperation with several partners, including MSD GmbH, Durbach.
In the two surface steaming processes (hood and sheet), the tiger nuts are completely killed off to a depth of around 25cm, which translates as an effective rate of around 95% over the entire area. After steaming, the steam-treated surface areas were observed. Growth from deeper lying tiger nuts, which the steam was not able to reach, can subsequently be killed off easily by mechanical or chemical means. In the case of pile steaming, e.g. via steam conveyor, the soil that is contaminated with tiger nuts is lifted completely and treated with steam.
Tiger nut sedge can be killed off completely with a soil temperature of 75°C. It is recommended that heat is maintained for at least 15 minutes in order to achieve a clean result.
More information can be found in the “Mit Dampf erste Befallstellen tilgen” (eradicate first infestations with steam) leaflet on www.agroscope.ch from July 2017.