|Koger Iii, Clifford|
Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2004
Publication Date: 1/26/2004
Citation: Burke, I.C., Clewis, S.B., Koger III, C.H., Miller, D., Porterfield, D., Price, A.J., Wilcut, J.W. 2004. Evaluation of trifloxysulfuron, pyrithiobac, and fluometuron weed management systems in cotton. In: Proceedings of Southern Weed Science Society. p. 260. Interpretive Summary:
Technical Abstract: Field experiments conducted in 2002 and 2003 at Goldsboro, NC, and in 2003 at Rocky Mount, Lewiston-Woodville, and Kinston, NC; Stoneville, MS; Auburn, AL; and St. Joseph, LA; evaluated the use of pyrithiobac with trifloxysulfuron in conventional cotton. Treatments were a factorial arrangement of preemergence (PRE) by postemergence (POST) by late post-directed herbicide options (LAYBY). PRE herbicide options included pendimethalin (840 g ai/ha), pendimethalin plus pyrithiobac (36 g ai/ha), or pendimethalin plus fluometuron (1,120 g ai/ha). Postemergence treatment options included no herbicide, trifloxysulfuron (5 g ai/ha) EPOST to 5 lf cotton, trifloxysulfuron plus pyrithiobac (36 g/ha) EPOST, or trifloxysulfuron (5 g/ha) EPOST to 5 lf cotton plus trifloxysulfuron (5 g/ha) POST to 7 lf cotton. LAYBY herbicide options included no herbicide or prometryn (1,120 g ai/ha) plus MSMA (2,240 g ai/ha). All EPOST, POST, and LAYBY treatments were applied with a NIS at 0.25% (v/v). Cotton injury in the form of discoloration was observed 2 wk after EPOST applications that included trifloxysulfuron or trifloxysulfuron plus pyrithiobac to 5 lf cotton at Kinston, NC, Lewiston, NC, and Auburn, AL. Injury was less than 10% in all treatments for which it was observed, transient in nature, and did not affect yields. Large crabgrass (Digitaria sanguinalis) control was greater with pendimethalin plus fluometuron PRE than pendimethalin plus pyrithiobac PRE or pendimethalin alone. Clethodim POST at 240g ai/ha plus 1% COC was required for adequate large crabgrass control. Pendimethalin plus fluometuron PRE and pendimethalin plus pyrithiobac PRE controlled redroot pigweed (Amaranthus retroflexus) greater than 72%, while pendimethalin PRE controlled this species 28%. Pendimethalin plus fluometuron PRE controlled common ragweed (Ambrosia artemisiifolia) and common lambsquarters (Chenopodium album) greater than 80%, while pendimethalin PRE and pendimethalin plus pyrithiobac PRE controlled these species 38% or less. Trifloxysulfuron controlled common lambsquarters, common ragweed, Palmer amaranth (Amaranthus palmerii), and redroot pigweed ' 80%, regardless of PRE treatment but controlled prickly sida (Sida spinosa) and jimsonweed (Datura stramonium) ' 28%. Pyrithiobac plus trifloxysulfuron EPOST controlled jimsonweed and prickly sida > 72%. Sequential trifloxysulfuron applications controlled ivyleaf morningglory (Ipomoea lacunosa), pitted morningglory (Ipomoea hederacea), sicklepod (Senna obtusifolia), and yellow nutsedge (Cyperus esculentus) greater than 82%. There was a main treatment LAYBY effect and the inclusion of a LAYBY treatment increased control of all weeds listed above 9-35 percentage points. The highest cotton yields required fluometuron PRE or pyrithiobac PRE or EPOST, trifloxysulfuron EPOST, and a LAYBY treatment of prometryn plus MSMA. There was a main treatment effect for LAYBY herbicide treatments with a yield increase of 3-50% for LAYBY containing herbicide systems. Pyrithiobac PRE or applied in mixture with trifloxysulfuron EPOST provided broad spectrum broadleaf weed control for cotton when used in conjunction with soil applied and LAYBY herbicides. The inclusion of multiple herbicide sites-of-action are important for management of herbicide resistance.