Suppression of Liverwort Growth in Containers Using Irrigation, Mulches, Fertilizers, and Herbicides

Abstract

Liverwort (Marchantia sp.) is often a serious weed in many nursery and greenhouse operations. Combinations of irrigation frequencies, surface mulches, surface fertilizers and herbicides were applied to the surface of the growing medium in 10-cm square pots planted with Rhododendron or Picea. Liverwort infestations were evaluated as the percentage of media surface covered. Mulches were placed at least 1/2-inch thick on the surface of the growing media. Five blocks of two pots per treatment were used in a completely randomized design. Oyster shell, hazelnut shell, and copper-treated geotextile mulches provided good suppression (less than 10% surface coverage) of liverwort for up to 6 weeks, while rockwool, peatmoss, coarse sand, perlite and pumice mulches required low-frequency irrigation to provide fair suppression (less than 40% surface coverage). Surface applications of oxadiazon (Ronstar), oryzalin (Surflan), iron oxide, copper sulfate, and manganese sulfate provided good suppression of liverwort for up to 4 weeks using low-frequency irrigation, but suppression was nearly eliminated if high-frequency irrigation was applied. Some combination applications of mulches and herbicides or fertilizers provided good suppression for 8 weeks (high-frequency irrigation) or 12 weeks (low-frequency irrigation). Liverwort suppression was fair when untreated geotextile mulches were used, but suppression was good (even under high-frequency irrigation) when copper-treated geotextile mulches were used.

Pre-emergence Liverwort Control in Nursery Containers

“…They (Svenson et al, 1997) described pre-emergence control with oxyfluorfen, oryzalin, isoxaben, and oxadiazon as fair, fair to good, fair to good, and fair to very good respectively. Svenson (1998) later documented slightly better preemergence liverwort control with oxadiazon compared with oryzalin in both low-and high-frequency irrigation settings. 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.…”

“…It is a primitive spore-bearing plant in the class Hepaticae. Liverwort thrives in conditions with high light (O'Hanlon, 1926), low ultraviolet radiation (True et al, 2006), high humidity or soil moisture (Svenson, 1998), and high fertility. These conditions are typical of many propagation and container production environments.…”

Liverwort (Marchantia Polymorpha) Control with Quinoclamine

“…However, these options have met with limited success (File et al 1999;Llewellyn et al 2003;Svenson 1997Svenson , 1998. At this writing, there is no herbicide specifically registered for POST liverwort control.…”

Weed Suppression for Container-grown Willow Oak Using Copper-treated Fabric Disks

“…Top dry weights were greater for trees grown with disks or preemergence herbicide, but root dry weights were not different (Table 2). Irrigation or fertilization rates other than those used in this study might alter these results (Svenson, 1998).…”

“…Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact. (Svenson, 1998). They also suppressed weed growth equal to or better than granular or sprayed preemergence herbicides (products not listed) when used on the substrate surface of containergrown azaleas (Rhododendron sp.)…”