Evaluating the efficiency of Metribuzin and Oxadiargyl mixture for pigweed control in potato (Solanum tuberosum L.) fields at different growth stages

In order to study the efficacy of herbicides mixtures of metribuzin and Oxadiargyl on the red root pigweed, a factorial field experiment was performed in the base of Complete Randomized Block Design with three replications in the research farm wich was located in Faculty of Agriculture and natural resources of University of Mohaghegh Ardabili in 2016. The First factor was above mentioned herbicides at doses of 0% metribuzin+ 100 % Oxadiargyl, 25% metribuzin + 75% Oxadiargyl, 50% metribuzin+ 50 % Oxadiargyl, 75% metribuzin+ 25 % Oxadiargyl, and 100% metribuzin+ 0% Oxadiargyl (estimation of percentage by use of normal dose of herbicides in different products); and second factor was application time of herbicides at post- or pre- emergence stages. The results show that the least density and dry weight of Pigweed was obtained at dose of 50% metribuzin+ 50% Oxadiargyl. Which was not showed statistically significant difference with doses of 25% metribuzin+ 75% Oxadiargyl and 0% metribuzin+ 100% Oxadiargyl. Accordingly, application of 50% metribuzin+ 50% Oxadiargyl reduced density and dry weight of red root pigweed by 82/23% and 92/96% respectively. Among herbicides application times, the highest percentage of reduction in weed dry weight of red root pigweed was at post-emergence stage. Key word: Dos- response, Oxadiargyl, Metribuzin, pigweed, weed biomass