Water quality is known to affect herbicide efficacy. Nursery well water containing naturally high pH and sodium levels was evaluated as spray solution for the postemergence grass herbicides Poast (sethoxydim), Fusilade (fluazifop P) and Acclaim (fenoxapropethyl). Using crabgrass as a test plant, high pH & sodium solution water reduced the effectiveness of all herbicides in one study. Other studies revealed that Poast (sethoxydim) was influenced the most with high pH & sodium water while the activity of Fusilade (fluazifop-P) and Acclaim (fenoxaprop-ethyl) was less affected. The solution water inhibition of Poast (sethoxydim) was overcome when Dash (a proprietary blend of surfactants used as a replacement for oil concentrate) was used as an adjuvant.

crabgrass control, water quality, surfactant
Poast (sethoxydim), [2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-l-one], Fusilade 2000 (fluazifop-P), [(R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid], Acclaim (fenoxapropethyl), [(±)-ethyl 2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy]propanoie acid].
Azalea ‘Christmas Cheer’ (Rhododendron × ‘Christmas Cheer’), Smooth crabgrass [Digitaria ischaemum (Schreb. ex Schweig.) Schreb. ex Muhl.]
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Author notes

Technical contribution 3249 from S.C. Agric. Expt. Station.

2Professor and former graduate students, Department of Horticulture, Clemson University, Clemson, SC.

3Triton Ag-98 (alkylarylpolyoxyethylene glycols), a trademark of Rohm and Haas Company. Philadelphia, PA.

4Agridex, Helena Chemical Company, Memphis, TN.

5Dash, a trademark of BASF Wyandotte Company. Parsippany, NJ.

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1992