Weed Management in Fresh Market Spinach (Spinacia oleracea) with S-Metolachlor

• Published in: Weed technology 2001-07, Vol.15 (3), p.511-516
• Main Authors: Fennimore, Steven A., Smith, Richard F., Milton E. Mc Giffen, Jr
• Format: Article
• Language: English
• Subjects: Agricultural soils; Biological and medical sciences; Chemical control; Crop science; Crops; Fundamental and applied biological sciences. Psychology; Herbicides; Hospital beds; Parasitic plants. Weeds; Phytopathology. Animal pests. Plant and forest protection; Planting; Soil organic matter; Spinach; Sustainable agriculture; Weed control; Weeds
• ISSN: 0890-037X; 1550-2740
• DOI: 10.1614/0890-037X(2001)015[0511:WMIFMS]2.0.CO;2

Field studies were conducted with fresh market spinach to examine crop tolerance and weed control with S-metolachlor. S-metolachlor was applied preemergence (PRE) at rates of 0.56, 0.72, 1.06, and 1.41 kg/ha and compared with the commercial standard cycloate at 3.4 and 4.5 kg/ha. Spinach was generally tolerant of S-metolachlor at rates up to 1.06 kg/ha on all soil types. S-Metolachlor at 0.56 to 0.72 kg/ha and cycloate at 3.4 kg/ha provided > 88% control of common purslane, nettleleaf goosefoot, and shepherd's purse. Control of common chickweed with S-metolachlor at ≥0.56 kg/ha was > 80%, whereas cycloate at 3.4 to 4.5 kg/ha was ineffective. Hand-weeding times in plots treated with S-metolachlor at 0.56 and 0.72 kg/ha were similar or lower than hand-weeding times in plots treated with cycloate at 3.4 kg/ha. Greenhouse studies were conducted to compare the relative tolerance of fresh market spinach to S-metolachlor and metolachlor. The${\rm GR}_{10}$values for S-metolachlor and metolachlor were 1.57 and 2.03 kg/ha, respectively. At rates above 2.2 kg/ha S-metolachlor is less selective in spinach than metolachlor. S-metolachlor is safe for PRE use in fresh market spinach at rates up to 1.06 kg/ha.