Reduced Rates of Dithiopyr Plus Isoxaben for Broadleaf Weed and Crabgrass Control in Bareground and Established Turf.

Field studies conducted in cool- and warm-season turfgrass regions of the United States evaluated the effect of dithiopyr plus reduced rates of isoxaben combinations on broadleaf weed and crabgrass control under bareground and established turf situations.  Applications were made prior to weed germination in both situations with glyphosate being applied to remove existing vegetation in the bareground or dormant grass applications.  A single application of both products was made in the cool-season region while two applications of dithiopyr and isoxaben approximately 8 weeks apart were made in the warm-season region.  Results from the cool-season region bareground trials showed that, for broadleaf weed control, application should contain at least dithiopyr at 200 g ai/ha + isoxaben at 280 g ai/ha and, for crabgrass control, application should contain at least dithiopyr at 200 g ai/ha + isoxaben at 560 g ai/ha.  Results from the cool-season region established turf trials showed that, for broadleaf weed control, application should contain at least dithiopyr at 200 g ai/ha + isoxaben at 560 g ai/ha and, for crabgrass control, application should contain at least dithiopyr at 200 g ai/ha + isoxaben @ 280 g ai/ha.  Results from the warm-season region bareground trials showed that, for broadleaf weed and/or crabgrass control, the first application should contain at least dithiopyr at 200 g ai/ha + isoxaben at 280 g ai/ha and total application of both active ingredients after two applications should cumulatively be at least dithiopyr at 480 g ai/ha and isoxaben at 560 g ai/ha.  Results from the warm-season region established turf trials showed that, for broadleaf weed control, the first application should contain at least dithiopyr at 200 g ai/ha + isoxaben at 280 g ai/ha and total application of both active ingredients after two applications should cumulatively be at least dithiopyr at 480 g ai/ha and isoxaben at 560 g ai/ha.  For crabgrass control in the warm-season region, the first application should contain at least dithiopyr at 200 g ai/ha + isoxaben at 180 g ai/ha and total application of both active ingredients after two applications should cumulatively be at least dithiopyr at 480 g ai/ha and isoxaben at 560 g ai/ha.