Primesource Quinclorac 1.5L Select (Drive XLR8) Liquid Crabgrass Killer Quinclorac 18.92% Residential and Non-Residential Turfgrass, Golf Course, Sod Farms Tank mix partner or sequential application required. Make 2 sequential applications of 1.0 fl. oz. (0.51 lb. AI/A) of Quinclorac 1.5L Select per 1,000 sq. ft. and an additional sequential application up to 0.90 fl. oz. (0.46 lb. AI/A) of Quinclorac 1.5L Select per 1,000 sq. ft. at 14- to 21-day intervals. Biotypes of large and smooth crabgrass in California have shown varied response to Quinclorac 1.5L Select. If control failure occurs following a full or split application, DO