The efficacy of quizalofop-P-ethyl herbicide to control of grass-weeds in groundnut fields

Slow growth of groundnut (Arachis hypogaea L.) makes it a poor competitor against weeds. The presence of weeds in fields leads to waste of water and nutrients and provides a habitat for growth of pathogens and insect pests, which adversely affects plant productivity. Herbicide application for keeping the fields free of weeds during the critical period of weed control helps minimize the costs of weeding. This experiment was carried out to determine the appropriate dose of quizalofop-P-ethyl for effective control of grass weeds in groundnut fields.

Field experiments were conducted in a randomized complete block design with nine treatments and four replications in Guilan, Ardabil and Golestan provinces. Quizalofop-P-ethyl 8.8%EC at four doses included 500, 550, 600 and 650 ml ha-1 (Kimia Sabz Moghan Company) was investigated for grass weed control and compared with haloxyfop R methyl ester 10.8%EC (0.75 L ha-1), clethodim 12%EC (1 L ha-1), sethoxydim 12.5%EC (3 L ha-1), fluazifop-P-butyl 15%EC (3 L ha-1).

Application of quizalofop-P-ethyl 8.8% EC at 500, 550, 600 and 650 ml ha-1 in Guilan province, led to 72, 79, 90, 85% number reduction and 70, 87, 96, 92% dry weight reduction of grass weeds (E.crus-galli and S.glauca) compared to weedy check, respectively. In Ardabil province, the control efficacy of quizalofop-P-ethyl at these doses for the number reduction of E. crus-galli was 57, 74, 90, 92%, respectively and for dry weight reduction was 60, 71, 90, 92%, respectively and for S.glauca, the number reduction was 46, 60, 71, 69%, respectively of and the dry weight reduction was 57, 84, 93, 92%, respectively. In Golestan province, application of quizalofop-P-ethyl at these doses led to 19, 24, 57, 58% number reduction, respectively and 23, 53, 78, 78% dry weight reduction of E. colonum, respectively and 33, 35, 39, 53% number reduction, respectively and 51, 59, 90, 92% dry weight reduction of S. glauca, respectively and 53, 61, 66, 58% number reduction, respectively and 87, 90, 92, 87% dry weight reduction of S. vercillata, respectively. In comparison between all treatments, the highest weed control efficiency of E. crus-galli with ≥ 90% was occurred in application of fluazifop-P-butyl and quizalofop-P-ethyl 600 and 650 ml ha-1 and then in quizalofop-P-ethyl 550 ml ha-1 with 71-79% density and dry matter reduction. The highest weed control efficiency of E. colonum was achieved in fluazifop-P-butyl, quizalofop-P-ethyl 600 and 650 ml ha-1, sethoxydim and clethodim which were ≥70% dry matter reduction of weed. In control of S. glauca, except of quizalofop-P-ethyl 500 ml ha-1, other treatments had effective weed control efficiency (≥ 80%). Dry weight reduction of S. verticillata, was achieved ≥85% compared to control with treatments. The highest yield increase in comparison to control in Guilan was achieved with the application of quizalofop-P-ethyl 600 ml ha-1, clethodim, quizalofop-P-ethyl 550 ml ha-1 and sethoxydim (74, 73, 70.5 and 61% respectively); in Ardabil, with application of quizalofop-P-ethyl 600 ml ha-1, sethoxydim, quizalofop-P-ethyl 650 and 550 ml ha-1 and fluazifop-P-butyl (162, 160, 156, 149 and 148%) and in Golestan with application of clethodim, quizalofop-P-ethyl 550 and 600 ml ha-1 and sethoxydim (297, 297, 261 and 243% respectively).

Due to the effective efficiency on quizalofop-P-ethyl 8.8% EC herbicide in control of grass weeds and producing a high groundnut yield compared to weedy control, it can be stated that this herbicide at a dosage of 600 ml ha-1in the form of a foliar spray in the stage of two- to four-leaf of narrow-leaf weeds is recommendable as an efficient herbicide to control of narrow-leaf (grass) weeds.