Evaluation of Chloridazon and Desmedipham Mixture with and without Surfactant for Weed Control in Sugar Beet

This experiment was conducted in 2002 and 2003 to evaluate the effects of chloridazon and desmedipham mixture plus a nonionic surfactant on weeds of sugar beet at Safi Abad agricultural research center of Dezful, Iran. The experimental design was a randomized complete block with 12 treatments and three replications. Treatments included postemergence application of the mixture of chloridazon + desmedipham at 3.2 + 0.78, 3.2 + 0.63, 2.4 + 0.63, 4 + 0.47 and 3.2 + 0.47 kg ai ha–1 and aforementioned herbicide treatments each plus a nonionic surfactant (Citowett) at 0.35% (v/v) at the 4- leaf stage of sugar beet, weed free and weedy check. In both years, application of the mixture of the chloridazon + desmedipham treatments each plus surfactant compared to the application of the same treatments without surfactant had 61 and 38% higher efficacy in reducing the total number of broadleaf weeds, respectively. Application of mixture of the chloridazon + desmedipham treatments at the abovementioned rates with and without surfactant provided 91 and 83% of sugar beet root yield, respectively. Weedy check plots had only 50% of sugar beet root yield. Application of the mixture of the chloridazon + desmedipham treatments at the abovementioned rates with and without surfactant provided 93 and 83% of pure sugar yield, respectively, Correspondence to: D. Ghanbari-Birgani, d.ghanbari@safiabad.ir D.Ghanbari-Birgani 46 while weedy check plots had only 52% of pure sugar yield.