isobolographic analysis for additive, synergism and antagonism effects in binary mixture of mesosulfuron + iodosulfuron and clodinafop-propargyl

the reduction of herbicide applications is a main research priority in recent years for herbicide reducing the risk of side-effects and costs from herbicides. therefore to predicting additive, synergism or antagonism effects mesosulfuron + iodosulfuron and clodinafop-propargyl two herbicides mixture on wild oat with isobole curvatures, greenhouse experimental in completely randomized design with 36 treatments (in dose-response arrangements) and four replicates for each experiment treatments were conducted at ferdowsi university of mashhad. treatments included mesosulfuron + iodosulfuron alone at doses of 0 , 2.4, 6, 12, 18 and 24 g ai ha-1, clodinafop alone at doses of 0, 6.4, 16, 32, 48 and 64 g ai ha-1 and six mixtures ratio of doses of two herbicides above mentioned as 100:0%,75:25%, 50:50%, 25:75% , 10:90% and 0:100%. the results showed mesosulfuron + iodosulfuron and clodinafop-propargyl at high dose rates showed complete control of wild oat. in addition concentration addition (ca) model describe fitted the data better than hewlett and voelund models. on the other hand, herbicides combination with each other showed additive effects on wild oat control, as by increasing the clodinafop-propargyl ratio in mixtures (90% clodinafop-propargyl + 10% mesosulfuron + iodosulfuron) increased wild oat control compared with other mixing ratios remarkably.