Background information and definitions
Due to the sensitive ecosystems where skunk cabbage Lysichiton americanus occurs, mechanical removal can be a useful method by which to control the population, particularly in the early years of infestation since only older plants of three years or older are capable of producing seeds (EPPO 2009). It is likely that the whole plant needs to be removed in order to be effective, as partial removal reportedly leads to vegetative reproduction and a high level of regeneration (Fuchs et al. 2003).
European and Mediterranean Plant Protection Organization (2009) Report of a Pest Risk Analysis for Lysichiton americanus. European and Mediterranean Plant Protection Organization Report Number 09-15078 rev, 61 pp.
Fuchs R., Kutzelnigg H., Feige B. & Keil P. (2003) Verwilderte Vorkommen von Lysichiton americanus Hultén & St. John (Araceae) in Duisburg und Mülheim an der Ruhr [Savaged occurrence of Lysichiton americanus Hultén & St. John (Araceae) in Duisburg and Muelheim an der Ruhr]. Tuexenia, 23, 373-379.
Supporting evidence from individual studies
A study in 2003-2008 in Switzerland (Buholzer pers. comm. (2009) In European and Mediterranean Plant Protection Organization 2009) found that annual physical removal of recently established skunk cabbage Lysichiton americanus plants over five years removed the entire stock. One hundred plants were removed in 2003, compared with 20 plants in 2004, and only a few individual plants in each of 2007 and 2008. In 2007 and 2008, no more plants had germinated. From 2003 to 2006, two people removed the plants by hand on an annual basis following which a monitoring programme was put in place to check for regrowth every second year. Total costs to 2009 were reportedly around €1000, declining from €500 in 2003, to just monitoring costs from 2008 onwards.Study and other actions tested
A study in 2005-2008 in the Netherlands (Rotteveel 2007) found that manual removal of mature skunk cabbage Lysichiton americanus was effective for a small outbreak of a small-growing plant. In 2008, two plants of over one year old, and dozens of new seedlings were found and subsequently removed by volunteers. This followed an annual inspection and removal programme which started in December 2005. Following removal, skunk cabbage plants were dug up, and then buried deep in the ground. No further information was available.Study and other actions tested
A study in 2004-2008 in the Taunus region in Germany (Fuchs et al. 2003) reports that manually removing mature skunk cabbage Lysichiton americanus was not effective as plants build up a seed bank which lasts for at least eight years. After the first four years of a twice yearly total removal programme, plants with leaf length in excess of 80cm were no longer found. However, a large number of plants still needed to be removed each year. In 2008, at least 3,773 skunk cabbage plants were removed in the Taunus region. The programme involved removal of all skunk cabbage stands twice each year. No further information was available.Study and other actions tested