Submitted to: Weed Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/1/2005
Publication Date: 9/1/2005
Citation: Hutchinson, P.J., Boydston, R.A., Ransom, C.V., Tonks, D.J., Beutler, B.R. 2005. Potato (solanum tuberosum) variety tolerance to flumioxamin and sulfentrazone in the pacific northwest. Weed Technology. 19:683-696. Interpretive Summary: Field studies were conducted in Pacific Northwest potato growing regions of Idaho, Oregon, and Washington to evaluate the tolerance of six major potato varieties that are currently grown to two new preemergence herbicides: flumioxazin and sulfentrazone. Each herbicide was tested at the proposed use rates and 2 to 2.6 X of the proposed use rates on Russet Burbank, Ranger Russet, Russet Norkotah, and Shepody potato varieties in Idaho and Washington and on Russet Burbank in Oregon. Alturas and Bannock Russet potato variety were included in the 2001 and 2002 Idaho trials. In both years and locations, some minor crop injury resulted with injury generally increasing as herbicide rate increased. Minor crop injury did not translate to reduced potato tuber yields. Crop injury from sulfentrazone was evident later in the season in Washington compared to Idaho. No clear consistent trend in relative tolerance among potato varieties to these two herbicides was evident. Major potato varieties grown in the Pacific Northwest appear to have adequate tolerance to these two herbicides when applied preemergence at normal use rates. Sulfentrazone and flumioxazin should provide growers with effective tools for control of nightshade species and other broadleaf weeds with adequate crop safety.
Technical Abstract: Field studies were conducted at Aberdeen, ID, Ontario, OR, and Paterson, WA in 2000, 2001, and 2002 to evaluate potato variety tolerance to two new preemergence herbicides: flumioxazin and sulfentrazone. In 2000, sulfentrazone was applied preemergence to Russet Burbank potato at 105, 140, 210, or 280 g ai/ha (1X, 1.3X, 2X, or 2.6X the proposed use rate) in Idaho, Oregon, and Washington, and flumioxazin was applied in Idaho and Washington at 53, 105, or 140 g ai/ha (0.5X, 1X, or 1.3X). Sulfentrazone was applied in 2000, 2001, and 2002 in Idaho at 1X or 2X, and in 2001 and 2002 at 1X, 2X, or 2.6X in Washington to Russet Burbank, Ranger Russet, Russet Norkotah, and Shepody potato varieties. Flumioxazin was applied at 0.5X, 1X, or 1.3X in Washington, and 1X or 2X in ID in 2001 and 2002 to the same varieties. Untreated controls of each variety were included for comparison. Alturas and Bannock Russet potato variety were included in the 2001 and 2002 Idaho trials. In the 2000 Russet Burbank trials in Idaho, Oregon, and Washington, crop injury caused by sulfentrazone ranged from 10 to 25% at 4 wks after treatment (WAT) and 1 to 5% 12 WAT. Tuber yields were not reduced as a result of any sulfentrazone treatment compared to the untreated controls. Russet Burbank injury at 4 WAT with flumioxazin ranged from 0 to 20% and injury was greatest with flumioxazin at 1X and 1.3X. At 12 WAT, injury from all treatments was 0% in Idaho and ranged from 0 to 11% in Washington. Flumioxazin did not reduce tuber yields compared to the untreated controls. In the Idaho 2000 variety trial, visual injury ranged from 5 to 25%, depending on herbicide treatment. Russet Burbank was more greatly affected than the other varieties and sulfentrazone 1X and 2X caused height reduction of Russet Burbank and Russet Norkotah compared with their respective untreated controls. Initial injury did not translate to significant tuber yield loss. Results from the 2002 Idaho and Washington trials were similar to Idaho 2000 results in that early injury caused by herbicide treatments did not result in tuber yield reductions. In the 2001 Idaho trial, flumioxazin or sulfentrazone 1X or 2X caused significant crop injury compared to the untreated control. Plant height of all six varieties was reduced significantly by both herbicides compared with the untreated controls at either 5 or 9 WAT depending on rate. Russet Burbank and Bannock Russet were most affected by the 2X rates of either herbicide. In Washington in 2001, injury as a result of sulfentrazone 2X or 2.6X was greater in Ranger Russet and Shepody compared with injury from those treatments in the other varieties. Tuber yields of all six varieties were reduced in 2001 by all herbicide treatments compared with the untreated controls in Idaho, and in Washington, Ranger Russet tuber yields were reduced by sulfentrazone 2.6X and flumioxazin 1.3X compared with the untreated control yields.