title: Can land managers control Japanese knotweed? Lessons from control tests in Belgium.
abstract: Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for land managers facing the invasion of this rhizomatous plant. We tested different chemical herbicides with two application methods (spraying and stem injection), as well as mechanical treatments, on knotweed clones throughout southern Belgium. The tested control methods were selected to be potentially usable by managers, e.g., using legally accepted rates for herbicides. Stem volume, height and density reduction were assessed after one or two years, depending on the control method. Labor estimations were made for each control method. No tested control method completely eradicated the clones. Stem injection with glyphosate-based herbicide (3.6 kg ha(-1) of acid equivalent glyphosate) caused the most damage, i.e., no sprouting shoots were observed the year following the injection. The following year, though, stunted shoots appeared. Among the mechanical control methods, repeated cuts combined with native tree transplanting most appreciably reduced knotweed development. The most efficient methods we tested could curb knotweed invasion, but are not likely to be effective in eradicating the species. As such, they should be included in a more integrated restoration strategy, together with prevention and public awareness campaigns.
authors.affiliation: Biodiversity and Landscape Unit, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Delbart
authors.forename: Grégory
authors.initials: G
authors.lastname: Mahy
authors.forename: Bernard
authors.initials: B
authors.lastname: Weickmans
authors.forename: François
authors.initials: F
authors.lastname: Henriet
authors.forename: Sébastien
authors.initials: S
authors.lastname: Crémer
authors.forename: Nora
authors.initials: N
authors.lastname: Pieret
authors.forename: Sonia
authors.initials: S
authors.lastname: Vanderhoeven
authors.forename: Arnaud
authors.initials: A
authors.lastname: Monty
mesh_terms: D001530:Belgium; D045468:Fallopia japonica / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D006540:Herbicides / Q000494:pharmacology; D027343:Rhizome / Q000187:drug effects / Q000254:growth & development / Q000502:physiology
chemical_list: D006540:Herbicides