the effect of low herbicide dose of clodinafop-propargyl on percentage of wild oat (avena ludoviciana) control, yield and economic return of wheat (triticum aestivum)

abstract a field experiment was conducted at plant pest and disease research institute in karaj,iran in 2005-2006 to determine the effect of low herbicide dose of clodinafop-propargyl on percentage of wild oat control, yield and economic return of wheat. the experiment included 2 wheat varieties (rooshan and niknejad (less and more competitiveness cultivar, respectively, 4 wild oat densities (0, 25, 50 and 75 plant m-2) and 4 herbicide doses (0, 25, 50 and 75(recommended rate) lit ha-1 (100%, 66%, 33% and 0% reduce herbicide dose respectively)) in factorial trial based on randomized block design with 4 replications. the highest wild oat control was obtain in recommended rate and reduce dose to 33 and 66% decreased wild oat control to 0.8 and 38.39% ,respectively. yields generally increased as rates increased recommended dose. there is no different between 33% reduce on the recommended dose and recommended dose, but 66% reduce on recommended dose couldn’t produce pleasure yield. in two cultivars economic returns increased exponentially as rates increased recommended dose, the maximum economic return was observed at the recommended herbicide dose but hadn’t different with 33% decrease in dose of herbicide. results of this study indicate reduction to 33% from the full recommended dosage is possible when wheat was grown in optimal density in weedy condition.