Applying chemical control to suppress liverwort (Marсhantia polymorpha L.) and other mosses when growing containerized seedlings of pine and spruce

Abstract

The spread of bryophytes (liverworts and green mosses) on the substrate surface in containers and cassettes poses a significant problem when growing containerized coniferous seedlings. It requires a complex control programme to significantly minimize the negative effect which mosses, in particular Marсhantia polymorpha L., pose to the growth of containerized pine and spruce seedlings. In addition to the preventive and agrotechnical measures, this programme should also involve application of the physiologically active substances. North American and European nurseries have faced this problem for a long time, Russian nurseries have started to experience it only in recent years due to increased output of containerized pine and spruce seedlings grown in greenhouses. In this paper, we assessed the effectiveness of some herbicides for moss control and their selectivity to pine and spruce seedlings of different ages. The following chemicals were applied in the tests: Goal 24% EC (a.i. oxyfluorfen), Stomp 33% EC (a.i. pendimethalin), Velpar 90% SP (a.i. hexazinone), Pledge 25% WP (a.i. flumioxazin), Mogeton 25% WP (a.i. quinoclamine), Granstar 75% WDG (a.i. tribenuron-methyl), Anchor-85 75% WDG (a.i. sulfometuron methyl) as well as cinnamon oil and baking soda. The experiments were conducted in greenhouses and outdoor fields. It was found that the pre-emergent (before the pine and spruce shoots appear) application of Mogeton WP and baking soda in the greenhouse resulted in the effective suppression of green mosses for up to 20 weeks after the treatment, without any signs of injury in seedlings. Under the same conditions, Goal EC, Stomp EC, Pledge WP and their mixtures in different combinations, as well as Velpar SP caused significant damage to pine and spruce seedlings. The post-emergent treatment by Velpar SP, Pledge WP, Mogeton WP, Granstar WDG, Anchor-85 WDG, as well as cinnamon oil and baking soda, provided effective and long-term control of liverwort and green mosses in cassettes without damage to the seedlings. Key words: Marchantia polymorpha L., pine, spruce, efficacy, selectivity