Dose response of some wheat field grass weeds under field and greenhouse conditions to three formulations of

Abstract

In order to investigate the dose response of some grass weeds of wheat fields to different Fenoxaprop-p ethyl formulations, field experiments were conducted in Khouzestan, Golestan and greenhouse experiments were conducted in Tehran, during 2003-2004. Experimental factors were three formulations of Fenoxaprop-p ethyl (Golsam, Giya and Bieser feld), each applied at four doses (0.4, 0.8, 1.2 and 1.8 L/ha). Dose response curves of the percent of reduction in number of weeds and their dry weight compared to the untreated control were fitted. Weed floras included winter wild oat (Avena ludoviciana Dur.), canary grass (Phalaris minor Retz.) and ryegrass (Lolium perenne L.) in Khouzestan, and the same weed flora but less canary grass in Golestan and winter wild oat in the greenhouse study. Results indicated that there was no significant difference between Giya and Bieser feld formulations. The efficacy of these formulations was better than Golsam. Also, the reduction in dry weight of narrow leaf weeds was similar in field studies but not in greenhouse study. Dose response of narrow leaf weeds to all Fenoxaprop-p ethyl formulations was not satisfactory at the recommended dose (1 L/ha) indicating that this herbicide should be applied at higher doses or be replaced with another narrow leaf herbicide like Clodinafop-propargil.