Herbicide Tolerance of Selected Ericaceous Species
This study was conducted to determine the tolerance of seven Ericaceous species to 15 herbicide treatments. Treatment response was species dependent. Pre-M (pendimenthalin) at the 2.2 kg/ha (2 lb ai/A) rate reduced top fresh weight of mountain laurel (Kalmia latifolia), flame azalea (Rhododendron calendulaceum) and Carolina rhododendron (Rhododendron carolinianum) while the 4.5 kg/ha (41b ai/A) rate affected these 3 species plus drooping leucothoe (Leucothoe fontanesiana), sourwood (Oxydendrum arboreum), Catawba rhododendron (Rhododendron catawbiense) and azalea ‘Hinocrimson’ (Rhododendron ‘Hinocrimson’). SWGC (pendimethalin) at 3.4 kg/ha (3 lb ai/A) reduced top fresh weight of sourwood, flame azalea and Carolina rhododendron. Goal (oxyfluorfen) + AG98 reduced fresh weight of every species except Carolina rhododendron. Snapshot DF (isoxaben + oryzalin) at 3.4 kg/ha (3 lb ai/A) reduced top fresh weight of mountain laurel and flame azalea. Mountain laurel showed a reduction in fresh weight for Pennant GR (metolachlor) at the 4.5 kg/ha (4 lb ai/A) rate. At the 2.2 kg/ha (2 lb ai/A) rate of Ronstar WP (oxadiazon), reduced Catawba rhododendron top fresh weight, however, Catawba rhododendron was not affected by the 4.5 kg/ha (4 lb ai/A) rate. The Poast (sethoxydim) treatment at 0.6 kg/ha (0.5 lb ai/A) + crop oil concentrate reduced fresh weight of flame azalea. SWGC at 3.4 kg/ha (3 lb ai/A), OH2 (oxyfluorfen + pendimethalin) at 3.4 kg/ha (3.0 lb ai/A), Gallery (isoxaben) at 1.1 kg/ha (1.0 lb ail A), Snapshot GR (isoxaben + trifluralin) at 4.0 kg/ha (3.75 lb ai/A), Derby (metolachlor + simazine) at 5.7 kg/ha (5.0 lb ai/A), and the ready-to-use formulation of sethoxydim did not reduce top fresh weight of any of the seven species tested.Abstract
Contributor Notes
The research reported in this publication was funded by the North Carolina Agricultural Research Service, Raleigh, NC 27695-7643. Technical assistance of Robbie Wooten, Everett Whitman, Shari Eakes, William Reece, and the staff of the Mountain Horticultural Crops Research Station is gratefully acknowledged.
2Professor, Associate Professor and Graduate Research Assistant, resp.