Abstract

Yellow nutsedge (Cyperus esculentus L.) is a major weed problem in many perennial woody crops. Dual 8E⁴ (metolachlor) at 4.5, 6.7, 9.0 and 13.5 kg/ha (4, 6, 8 and 12 lb/A) was evaluated in the field for 4 years to determine phytotoxicity to 11 varieties of azaleas. Also evaluated were Ericaceous species including coast leucothoe, compact Japanese andromeda, and Rhododendron × ‘PJM’. Fall or spring applications of metolachlor at rates up to 13.5 kg/ha (12.0 lb/A) caused no injury to the established azaleas ‘Delaware Valley White’, ‘Hershey Red’ and ‘Hinocrimson’. Some temporary injury occurred to newly planted ‘Hinocrimson’ azaleas treated with metolachlor at 6.7 kg/ha (6.0 lb/A). A July application at this same rate caused some temporary injury to established ‘Delaware Valley White’, ‘Double Pink’, ‘Hershey Red’, ‘Hot Shot’, ‘Karen’, ‘Lady Robin’, ‘Rosebud’ and ‘Tradition’ azaleas and ‘Coast lecothoe’ and ‘PJM’ rhododendron. No reduction in crop quality or size was observed with any species at time of crop harvest.