Published online by Cambridge University Press: 12 June 2017
Quinclorac is a systemic herbicide registered to control annual grass and broadleaf weeds in rice. Field research was conducted to determine the most effective quinclorac treatment for leafy spurge control. Leafy spurge control 12 mo after treatment (MAT) averaged 38 and 77% when quinclorac was applied at 0.56 and 1.7 kg ae/ha, respectively. Quinclorac applied with the crop-oil-based adjuvant Scoil provided similar leafy spurge control compared to quinclorac applied alone. Quinclorac plus Scoil applied with picloram provided better leafy spurge control than quinclorac plus Scoil alone. The optimum date for fall treatment with quinclorac is broad. Quinclorac at 1.1 kg/ha plus Scoil at 2.3 L/ha applied on September 1, September 15, October 1, and October 15 provided similar leafy spurge control and averaged 56% 12 MAT.