Eradication of Common Liverwort from a Soilless Growing Medium

Abstract

Common liverwort (Marchantia polymorpha L.) is an increasingly troublesome weed in containerized plant production. Postemergence applications were made to try to eradicate established stands of liverwort. Treatments consisted of sprays of quinoclamine at 1× and 2× rates and oxadiazon at the highest label rate, broadcast applications of sodium carbonate peroxyhydrate at 1x and 3x rates and four granular herbicides (flumioxazin, oxadiazon, oxyfluorfen + pendimethalin, and prodiamine) applied at label rates. The granular herbicides were applied both alone and with the sodium carbonate peroxyhydrate treatments. Herbicides were applied to common liverwort growing on an 80% aged pine bark: 20% Sphagnum peat-based soilless growing medium contained in 10-cm diameter plastic pots located in a double-poly covered greenhouse. At 2 weeks after treatment (WAT), control was best (93% to 100%) for both quinoclamine and the 3× peroxyhydrate treatments, intermediate (68% to 83%) for the 1× peroxyhydrate treatments, and not significant for any of the preemergence herbicides used alone. At 4 WAT, slight regrowth was evident in plots in which the treatments had an initial effect and the 1x peroxyhydrate + flumioxazin was as effective as the 3× peroxyhydrate and the 2× quinoclamine treatments. At 6 WAT, control was excellent in the 3× peroxyhydrate and 1× peroxyhydrate + flumioxazin treatments. Control was less, but still evident, in the quinoclamine and other 1× peroxyhydrate treated plots. While none of the treatments had completely eradicated common liverwort in all replications at 10 WAT, control was still excellent to good in many of the peroxyhydrate + preemergence herbicide-treated plots.