This Is AuburnElectronic Theses and Dissertations

Liverwort Control in Container-grown Nursery Crops

Date

2006-08-15

Author

Newby, Adam

Type of Degree

Thesis

Department

Horticulture

Abstract

The objective of this study was to evaluate preemergence and postemergence liverwort control in container-grown nursery crops. In Chapter II, experiments were to evaluate effectiveness of selected chemicals for postemergence liverwort control and crop safety in container nursery crops. In Experiment 1, Gentry provided 98% to 100% postemergence control on juvenile liverwort and 84% to 99% postemergence control on mature liverwort 14 DAT. TerraCyte provided moderate postemergence control on juvenile (79%) and mature (56%) liverwort 14 DAT. BroadStar provided 39% and 5% postemergence control on juvenile and mature liverwort, respectively. In Experiment 2, a Gentry concentration of 3.8 g ai/L (0.5 oz/gal) applied at 2036 L/ha (218 gal/A) provided 77% postemergence control 14 DAT, while the low Gentry rate provided 53% postemergence control. Ronstar G provided 6% postemergence control, while BroadStar provided 13% control 14 DAT. TerraCyte provided 82% postemergence control 14 DAT. In Experiment 3, Gentry and Ronstar G caused no injury to Achillea millefolium L. ‘Colorado’, Coreopsis grandiflora Hogg ex Sweet ‘Early Sunrise’, and Dianthus gratianopolitanus L.‘Spotti’. In Experiment 4, Gentry applied at concentrations of 1.9, 3.8, and 7.5 g ai/L applied at 2036 L/ha (218 gal/A) resulted in no significant plant injury or differences in plant indices to Buddleia davidii Franch, Cotoneaster salicifolius Franch, Hosta ‘Francee’, Ilex x meserveae S.Y. Hu, Magnolia grandiflora L., or Rhododendron x ‘Midnight Flare.’ Experiments in Chapter III evaluated the effects of differing concentrations and spray volumes of Gentry with and without surfactant as well as the effects of TerraCyte and BroadStar on postemergence liverwort control in propagation. In Experiment 1, Gentry applied at a concentration of 3.8 g ai/L provided excellent control regardless of spray volume or surfactant. TerraCyte provided poor postemergence control throughout the experiment (<30%). In Experiment 2, Gentry provided excellent postemergence liverwort control (93%-100%) 3 and 14 DAT regardless of concentration, spray volume, or surfactant. TerraCyte provided good postemergence liverwort control (74%-88%) 3 and 14 DAT. BroadStar provided only 21% postemergence liverwort control 14 DAT. In Experiment 3, Gentry provided 100% postemergence liverwort control 3 and 14 DAT regardless of concentration, spray volume, or surfactant. TerraCyte and experimental TerraCyte treatments provided 90% to 97% postemergence control 3 and 14 DAT. BroadStar provided only 58% postemergence liverwort control 14 DAT. The objective of studies in Chapter IV was to evaluate the of residual granular herbicides, Gentry, and diuron on preemergence liverwort control. In Experiment 1, BroadStar and Ronstar G provided the most effective preemergence liverwort control 17 WAT. In Experiment 2, by 18 WAT, liverwort coverage in containers treated with Gentry was similar to non-treated controls, while BroadStar, Ronstar G, and Rout 3G provided significant preemergence liverwort control. In Experiment 3, liverwort coverage in containers treated with Gentry was similar to non-treated controls 9 WAT. There was no liverwort present in containers treated with diuron applied at 0.56 and 1.12 kg ai/ha (0.5 and 1.0 lb ai/A). At 12 and 17 WAT, percent liverwort coverage in containers treated with Gentry was similar to non-treated controls, while no liverwort was present in containers treated with diuron. Experiments in Chapter V evaluated the use of lower Gentry concentrations and spray volumes than currently recommended and evaluated diuron for postemergence liverwort control in containers. In Experiment 1, Gentry concentrations of 1.87 and 3.75 g ai/L applied at 509 and 1018 L/ha provided excellent postemergence liverwort control 7 and 14 DAT (81%-99%). Diuron applied at 1.12 kg ai/ha provided 86% postemergence liverwort control. Linuron provided no postemer