Effect of pre and post emergence herbicides and mixture of them on control of spring and summer weeds in apple and grape orchards

These experiments were conducted in order to study effect of pre and post emergence herbicides on grass and broad leaf weeds in vine orchards in Qazvin and apple orchards in Tehran in 2008-2009. Experimental design was factorial with two factors and three replications. Factor one was pre emergence herbicides (diuron (WP 80%) 1.6 kg a.i. ha-1, napropamide (SC 45%) 4.1 kg a.i. ha-1, oxyfluorfen (EC 24%) 0.48 kg a.i. ha-1, trifluralin (EC 48%) 1.2 kg a.i. ha-1, and check (no herbicide) and factor two was post emergence herbicides (glayphosate (SL 41%) 2.5 kg a.i. ha-1 8 kg ha-1 ammonium sulfate, glayphosate (SL 41%) 2.5 2.5 kg a.i. ha-1 plus ammonium sulfate 8 kg ha-1, triclopyr (EC 62%) 1.2 kg a.i. ha-1, and triclopyr 1.2.2 kg a.i. ha-1). The results showed that pre emergence herbicides, especially napropamide, oxyfluorfen and trifluralin controlled annual winter weeds. One time use of glayphosate could control annual weeds, but not perennial weeds. One and two times use of triclopyr and two times glyphosate controlled perennial weeds. Use of pre emergence plus post emergence herbicides controlled perennial weeds well. Napropamide and trifluralin plus triclopyr reduced weeds, but diuron plus post emergence herbicides provided best broadleaf weed suppression. As compared to glayphosate, triclopyr controlled weeds with delay.