Long-term chemical control of Reynoutria species in the Czech Republic
A study on the management of Reynoutria species in the Czech Republic highlights the need for a long-term management strategy for effective control. The study evaluates 17 years (2007 – 2023) of long-term chemical control with glyphosate-based herbicide in the Morávka river floodplain. The first record of Reynoutria species in this area is from the 1940s and currently three species (R. x bohemica, R. japonica and R. sachalinensis) are present. Before the start of the study in 2007, Reynoutria stands covered 29% of the study area (96.9 ha). Throughout the study, Reynoutria was controlled with glyphosate applied with a backpack sprayer, predominantly in August and September each year. The population was cut mechanically before herbicide application. Near the Morávka reservoir, foliar spraying was replaced by stem injection to reduce environmental risk. As a result of whole area chemical management, the area of Reynoutria decreased to 19.6% (65.3 ha) in 2009, and to 14.5% (48.2 ha) in 2013. The infested area was maintained at a similar size in the proceeding years with a minimum area of 41.8 ha recorded in 2018. Based on the results of the study, the following procedure for effective chemical management is recommended (1) in large infested sites, the first aim is to reduce the distribution of Reynoutria stands to isolated stands, (2) then, herbicide application only in periods of 3-5 years depending on the local context and the rate of regrowth, and (3) at infested sites exposed to soil disturbances herbicides should be applied immediately to target newly resprouting individuals.
Sources
Švec P, Perglová I, Fröhlich V, Laštovička J, Seidl J, Růžičková K, Horáková I, Lukavský J, Ferko M, Štych P, Pergl J (2024) Perseverance of management is needed – Efficient long-term strategy of Reynoutria management. NeoBiota 94, 261–288. https://doi.org/10.3897/neobiota.94.122337