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Field experiments were conducted in 1999 and 2000 at the Plant Breeding
Unit (Lucedale fine sandy loam) in Tallassee, Alabama and Tennessee
Valley Substation (Decatur silt loam), Belle Mina, Alabama to evaluate
glufosinate weed control systems and tolerance in Liberty Link cotton.
Glufosinate was applied postemergence over-the-top (POST) at (a) 0.27, A separate cotton tolerance trial was also carried out at both locations. All plots were maintained weed free by applying pendimethalin PRE at 0.75 lb ai/A followed by cultivation and hoeing. POST applications of glufosinate included (a) single applications at 0.36 and 0.72 lb ai/A to 2-, 4-, 8-L and first bloom (FB) cotton, (b) double applications at 0.36 lb ai/A to 2- and 4-L, 4-and 8-L cotton (c) triple applications at 0.24 lb ai/A applied to either 2-, 4-, 8-L or 4-, 8-L, FB cotton. Results varied with location. In Tallassee, single applications of Liberty at In Belle Mina, single applications of Liberty at 0.27 lb ai/A to 2- and 4-L cotton provided weed control greater than 85 % for all species except for prickly sida, with 81% control. Increasing the rate to 0.36 or 0.54 lb ai/A improved prickly sida control to 86 and 89% respectively. Furthermore morningglory control improved from 86% control to 92 and 93% with the higher rates. Increasing the rate only marginally improved control of other species. Single applications of either fluometuron, norflurazon or prowl PRE followed by glufosinate at 0.27 lb ai/A at 4- and 8-L stage provided greater than 93% control of all species. Results from the tolerance study at both locations showed that seed cotton yield was not adversely affected by glufosinate at any application rate or stage of application. Single, double and/or triple applications of glufosinate totaling 0.72 lb ai/A applied at various stages as late as FB did not reduce yield. |
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©National Cotton Council, Memphis TN |
Document last modified XXXXXX, XXX XX 2001
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