Controlling Liverwort and Moss Now and in the Future

Abstract

<jats:p>The liverwort, marchantia (<jats:italic>Marchantia polymorpha</jats:italic>), and silver thread moss (<jats:italic>Bryum argenteum</jats:italic>) are two highly invasive and difficult to control pests in containerized ornamentals. Container trials were conducted evaluating marchantia and silve r thread moss control with preemergence and postemergence applications of chlorothalonil, captan, ammonium chlorides, hydrogen dioxide, flumioxazin, oxyfluorfen, pelargonic acid, acetic acid (vinegar), copper sulfate, cinnamaldehyde, prodiamine, and oxadiazon. Flumioxazin, oxyfluorfen, pelargonic acid, acetic acid, and oxadiazon provided acceptable preemergence and/or postemergence marchantia and silver thread moss control; however, no product provided acceptable control of these weeds at all evaluations. Under controlled environmental conditions marchantia and silver thread moss were controlled with flumioxazin, oxyfluorfen, pelargonic acid, acetic acid, and oxadiazon. In addition to providing postemergence control of these weeds, flumioxazin, oxyfluorfen, and oxidiazon also had residual activity when applied to potting media. However, the length and effectiveness of the preemergence control with flumioxazin, oxyfluorfen, and oxadiazon was dependant upon formulation. In a separate study comparing granular and sprayable formulations of flumioxazin, oxyfluorfen, and oxidiazon, results indicated control of established marchantia and silver thread moss was greater with sprayable formulations when compared with granular formulations. Similarly, sprayable formulations of these active ingredients enhanced residual marchantia and silver thread moss control. The granular and sprayable formulations of flumioxazin provided greater preemergence and postemergence control of marchantia and silver thread moss when compared with granular or sprayable formulations of oxyfluorfen and oxadiazon, and of the products evaluated, displayed the greatest level of activity against these weeds.</jats:p>

Impact of Container Nursery Production Practices on Weed Growth and Herbicide Performance

“…As profit margins decline and the input costs continually increase, researchers and nursery growers have looked for ways to decrease production costs. From a weed control perspective, this would include many different preventative and sanitation measures, as well as chemical and nonchemical methods of weed control to improve crop growth, reduce economic burden, and increase product marketability (Case et al, 2005;Fausey, 2003).…”

Pre-emergence Liverwort Control in Nursery Containers

“…Wilson and Hughes (1985) reported that oryzalin applied at 9-week intervals provided 99% liverwort control compared with 76% control with oxadiazon applied at a similar frequency. Fausey (2003) reported that flumioxazin sprayed as a 50% water dispersible granule provided 100% pre-emergence liverwort control 35 d after treatment (DAT) and 74% pre-emergence control 60 DAT. In a separate experiment, the same product provided 98% preemergence control 60 DAT, whereas flumioxazin applied as a 0.17% granular provided 95% pre-emergence control 60 DAT (Fausey, 2003).…”

“…Fausey (2003) reported that flumioxazin sprayed as a 50% water dispersible granule provided 100% pre-emergence liverwort control 35 d after treatment (DAT) and 74% pre-emergence control 60 DAT. In a separate experiment, the same product provided 98% preemergence control 60 DAT, whereas flumioxazin applied as a 0.17% granular provided 95% pre-emergence control 60 DAT (Fausey, 2003). However, none of the aforementioned herbicides are labeled for use in enclosed structures where liverwort pressure is greatest.…”

A Review of Weed Control Practices in Container Nurseries

“…Silver thread mosses (Bryum argenteum) and liverwort (Marchantia spp.) also can be problematic in container production (Mathers, 2003) and have spread throughout the U.S. nursery industry rather quickly (Fausey, 2003). Both pests are highly invasive and diffi cult to control in containerized ornamentals (Fausey, 2003).…”