Dose responses of some grass weeds to 2,4-D + MCPA and Clodinafop-propargyl tank mixture in wheat fields

In order to study the possibility of tank mixing of 2،4-D plus MCPA and clodinafop propargyl in wheat fields in Iran، some experiments were conducted in 2003 and 2004. Field experiments were conducted in 2003 as a randomized complete block design with a factorial arrangement of treatments and four replications in Meybod and Oromieh. One of the experimental factors was 2،4-D plus MCPA at 0، 975، and 1300 g a. i. /ha، and the other one was clodinafop propargyl at 0، 64، 80، 96، and 112 g a. i. /ha. In greenhouse experiment، the same treatments were conducted in Iranian Plant Protection Research Institute Greenhouses. Weed floras included winter wild oat (Avena ludoviciana Dur.)، mouse barly (Hordeum murinum L.) and canary grass (Phalaris minor Retz.) in Meybod، cereal rye (Secale cereale L.)، winter wild oat and downy brome (Bromus tectorum) in Oromieh and winter wild oat، canary grass and ryegrass (Lolium perenne L.) in greenhouse. Results indicated that clodinafop propargyl could control winter wild oat and canary grass at the recommended dose (64 g a. i. /ha). Tank mixing of 975 g a. i. /ha 2،4-D plus MCPA with clodinafop propargyl reduced efficacy of clodinafop propargyl at the recommended dose (64 g a. i. /ha). But increasing the dosages of clodinafop propargyl to 112 g a. i. /ha could omit the antagonistic effects of 2،4-D plus MCPA. Tank mixing of 1300 g a. i. /ha 2،4-D plus MCPA and clodinafop propargyl was not satisfactory indicating that this dose of 2،4-D plus MCPA should not be applied with Clodinafop-propargil.