Abstract

Four experiments were conducted in Aurora, OR, and Auburn, AL, to evaluate effectiveness of herbicides for postemergence liverwort control. A sprayable herbicide, quinoclamine (Gentry 25-WP), was applied at rates between 1.8 and 7.6 kg ai/ha (1.6 and 6.8 lb ai/A), with or without a surfactant, and in spray volumes of 1019 or 2037 liters/ha (109 or 218 gal/A). Across all experiments, postemergence liverwort control was good (>90%) at the lowest rate when liverwort infestation was light (liverwort covered ≤25% of the substrate surface with no sporocarps). When liverwort infestation was high (liverwort covered ≥60% of the substrate surface with some sporocarps present), or in conditions favorable to liverwort growth, control improved by using higher rates or including a surfactant. At the highest labeled rate (7.6 kg ai/ha (6.8 lb ai/A)), postemergence liverwort control up to 14 days after applications was 96 to 100% across all four experiments. Long-term liverwort control through 42 to 56 days after application varied depending on the location and time year, with control decreasing as environmental conditions allowed for increased liverwort vigor. Sodium carbonate peroxyhydrate (TerraCyte) provided poor to moderate control, and was largely dependent on liverwort vigor. Flumioxazin (BroadStar) provided unacceptable postemergence control across all experiments.