Bahiagrass grown for foundation seed had become infested primarily with knotroot foxtail, and secondarily with yellow foxtail. Seed from both foxtail species are mechanically inseparable to certified seed standards from bahiagrass seed. Studies were conducted to determine if pendimethalin applied PRE, in combination with multiple POST applications of diclofop would sufficiently control and/or suppress foxtail seed head production so as to prevent contamination of the harvested bahiagrass seed. Neither pendimethalin nor multiple applications of diclofop were detrimental to bahiagrass seed head production. Although pendimethalin had no effect of knotroot foxtail seed head production, diclofop was effective. Depending on the year, between one and three POST applications of diclofop at 1.12 kg/ha each were effective in reducing, but not completely eliminating, knotroot foxtail seed head production in bahiagrass.

Nomenclature: diclofop, pendimethalin, knotroot foxtail, Setaria parviflora (Poir.) Kerguelen SETGE, yellow foxtail, Setaria glauca (L.) Beauv. SETLU, bahiagrass, Paspalum notatum Flugge PASNO