| Abstract/Contents: | "Experiments were performed to evaluate carfentrazone for weed control and turfgrass tolerance. Carfentrazone, a contact herbicide that disrupts cell membranes, was applied alone (Quicksilver), tank-mixed with translocated herbicides, or applied in a pre-packaged formulation of carfentrazone + 2,4-D, MCPP, and dicamba (Speed Zone). In the first experiment, Quicksilver 2 EW was applied at 2.33, 4.66, or 9.32 fl oz/A to common bermudagrass, 'Tifway' bermudagrass, common centipedegrass, and 'Raleigh' St. Augustinegrass. All rates were higher than the maximum labeled rate of 2.1 fl oz/A. No unacceptable injury was observed on any of the warm-season turfgrasses evaluated. Quicksilver injured common bermudagrass 8-15% at 7 days after treatment (DAT) while injury of 8-15% was only observed at 3 DAT on 'Tifway' bermudagrass. Injury to centipedgrass was only observed with the highest rate of Quicksilver. Three to 5% injury was observed at 3, 7, and 30 DAT. Injury to St. Augustinegrass from 4.66 fl oz/A was only observed at 3 DAT. Injury to St. Augustinegrass from 9.32 fl oz/A was 8, 5, 5, 5, 10, and 15% at 3, 7, 14, 30, and 45 DAT, respectively. All treatments were applied on September 30, 2002 and evaluations were discontinued on November 14, 2002 due to frost. Quicksilver was also evaluated for Virginia buttonweed control. The objective of this experiment was to evaluate the effects of Quicksilver for Virginia buttonweed control and turf injury on ALS-inhibiting herbicides and Trimec Classic, all of which are mobile herbicides. Quicksilver alone did provide some burndown of Virginia buttonweed. The highest control (65%) from 1.3 fl oz/A Quicksilver was at 16 DAT; control decreased at the later rating dates. The data from the first two evaluations at 7 DAT indicate that Quicksilver did provide a faster burndown of Virginia buttonweed when added to several treatments compared to those treatments applied alone. Control with 1.3 fl oz/A Quicksilver + 2.0 pt/A Trimec Classic was 58% at 7 DAT compared to 23% with Trimec Classic alone. With 1.3 fl oz/A Quicksilver + 0.5 lb ai/A Image at 7 DAT, control was 43% compared to 23% with Image alone at the same rating date. At the later rating dates Quicksilver generally did not have an effect on control with the other herbicides except with Image and Monument. Virginia buttonweed control with Quicksilver + Image or Quicksilver + 0.56 oz/A Monument was 68 to 85% at 57 and 92 DAT compared to 40 to 63% with Image or Monument alone, respectively. The only injury to bermudagrass from any treatment was at 7 DAT and was no more than 10%. In a third experiment, Speed Zone 2.2 L which contains 0.05, 1.53, 0.48, and 0.14 lb ae/gal carfentrazone, 2,4-D, MCPP, and dicamba, respectively, was compared to Trimec Classic 2.72 L which contains 1.98, 0.53, and 0.21 lb ae/gal 2,4-D, MCPP, and dicamba, respectively. Comparing these two products at 3 pt/A, Speed Zone controlled white clover better than Trimec Classic at 7, 15, and 21 DAT. Control with Speed Zone was 35, 80, and 88%, respectively at these dates compared to 13, 60, and 65%, respectively, with Trimec Classic. Buckhorn plantain control was also better with Speed Zone at the same dates compared to Trimec Classic. Control of buckhorn plantain was 40, 80, and 85%, respectively, with Speed Zone at those dates compared to 20, 60, and 65%, respectively with Trimec Classic at the same dates. Control of dandelion by the two products did not differ. Control evaluated from 29 through 85 DAT was the same for all three weeds evaluated." |
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