Because of the limited number of herbicides in spinach, beet, and swiss chard, a screening study was initiated to identify new preemergence herbicides. Field soil at the study was a fine sandy loam. The study was initiated on 8 Apr. 2004 at Bixby, Okla. Each plot had four direct seeded rows of spinach, beet and chard. 22 treatments were replicated four times in a RBD that included a nontreated check. Treatments used 12 preemergence herbicides. Herbicides were applied PRE with a research sprayer at 20 GPA in a 6-ft swath perpendicular to crop rows. The experimental area received 0.5 inch of irrigation after application. Callisto (mesotrione) and V10146 (Valent exp. compound) both resulted in 100% death of beet, chard and spinach seedlings. Herbicides that had injury at or below Dual Magnum included Pyramin (pyrazon), Nortron (ethofumesate), Lorox (linuron), and Bolero (thiobencarb) tank-mixed with Bio-Power. Yields were zero for the nontreated check and several treatments due to weed competition and the lack of crop plants in some plots. Treatments with the highest beet yields included Dual Magnum at 0.5 lbs/acre, Pyramin at 3.6 lbs/acre, and Outlook (dimethenamid-P) at 0.25 lbs/acre (11,822, 8,034, 8,010 lbs/acre respectively). Highest chard yields were from Dual Magnum at 0.5 lbs/acre, Pyramin at 3.6 lbs/acre, Outlook at 0.5 lbs/acre + Bio-Power, and Outlook at 0.5 lbs (12,753, 12,596, 11,495, and 10,563 lbs/acre, respectively). Spinach yields were highest for Dual Magnum at 0.5 lbs/acre, Define (flufenacet) at 0.3 lbs/acre, and Outlook at 0.5 lbs/acre + Bio-Power (4,465, 4,259, and 3,207 lbs/acre, respectively).
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