Submitted to: Weed Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/18/2003
Publication Date: 8/1/2004
Citation: Price, A.J., Wilcut, J.W., Cranmer, J.R. 2004. Flumioxazin Preplant Or Postemergence-Directed Application Timing Followed By Irrigation At Emergence Or After Pds Treatment Does Not Influence Cotton Yield. Weed Technology. 18:310-314. Interpretive Summary: Cotton growers in reduced tillage systems typically include preplant burndown herbicides to kill winter cover crops and emerged weeds as well as postemergence-directed herbicides that are applied later in growing season to control weeds until cotton harvest. Flumioxazin, (trade name Valor¿), is a herbicide registered for burndown application and is being evaluated for use as a postemergence-directed application. However, research has shown that flumioxazin applied as a preplant burndown or as a postemergence-directed spray can injure cotton if rain splashes soil particles that are coated with flumioxazin onto cotton foliage. Due to injury concerns, research was conducted to investigate potential causes of observed injury. Results showed that flumioxazin applied up to 7 days before cotton planting and irrigated at emergence injured cotton less than 7% two weeks after emergence. Results also showed that flumioxazin applied postemergence-directed followed by irrigation did not injure cotton. In all experiments, cotton lint yields were not affected by observed injury.
Technical Abstract: Three experiments were conducted in Lewiston, North Carolina in 1999 through 2002 to evaluate the influence of various application timings of flumioxazin preplant (PP) and postemergence-directed (PDS) on cotton. In experiment one, flumioxazin was evaluated in a reduced-tillage system at 71, 105, or 140 g ai/ha in mixture with glyphosate, applied at 28, 14, or 7 d before planting (DBP), followed by irrigation at cotton emergence. Cotton treated PP with flumioxazin at any rate and irrigated at emergence injured cotton < 7% at 2 wks after emergence (WAE) and < 6% 5 WAE. In experiment two, flumioxazin was evaluated in a conventional-tillage system at 71 or 105 g/ha as a PDS treatment applied to dry soil, wet soil, and dry soil irrigated immediately after application when cotton was 20 to 30 cm height. Cotton treated with flumioxazin PDS at either rate applied to dry soil, wet soil, or dry soil followed immediately by irrigation was not injured. In the third experiment, flumioxazin at 71 g/ha alone or in mixture with glyphosate at 1.12 g/ha was applied at 30, 21, 14, and 0 DBP in a conventional-tillage system. Cotton treated with flumioxazin alone or in mixture with glyphosate applied at any time did not injure cotton. In all experiments, cotton lint yields were not influenced by herbicide treatment.