Minimum doses of metribuzin that provide satisfactory control (>90%) of redroot pigweed (Amaranthus retroflexus L.) and wild mustard (Sinapis arvensis L.), 2 troublesome weeds of potato crops planted in spring and autumn, respectively, were assessed. | Research Article Turk J Agric For 34 (2010) 467-474 © TÜBİTAK doi: The effects of reduced doses and application timing of metribuzin on redroot pigweed (Amaranthus retroflexus L.) and wild mustard (Sinapis arvensis L.) İbrahim KAHRAMANOĞLU*, F. Nezihi UYGUR Department of Plant Protection, Çukurova University, 01330 Adana – TURKEY Received: Abstract: Minimum doses of metribuzin that provide satisfactory control (>90%) of redroot pigweed (Amaranthus retroflexus L.) and wild mustard (Sinapis arvensis L.), 2 troublesome weeds of potato crops planted in spring and autumn, respectively, were assessed. Greenhouse experiments were conducted using 100%, 80%, 60%, 40%, 20%, and 0% of the -1 registered dose (525 g . ha ) of metribuzin applied to the weeds grown in plastic pots. Dry weight data from the experiments were subjected to nonlinear regression analysis and the effective doses of metribuzin that caused a 90% -1 reduction in dry weight (ED90) were estimated. Metribuzin at doses of and g . ha resulted in a 90% reduction in the dry weight of A. retroflexus when applied at the BBCH 12-15 and BBCH 16-19 growth stages, respectively. -1 Metribuzin at doses of and g . ha provided 90% control of S. arvensis at the BBCH 12-15 and BBCH 1619 growth stages. Key words: Dose-response curve, metribuzin, minimum dose, satisfactory control efficiency, weed development stage Metribuzinin azaltılmış doz ve uygulama zamanlarının, kırmızı köklü horozibiği (Amaranthus retroflexus L.) ve yabani hardal (Sinapis arvensis L.)’a etkisi Özet: Bu çalışma ile, ilkbahar ve sonbahar patates dikim alanlarında sorun olan kırmızı köklü horozibiği (Amaranthus retroflexus L.) ve yabani hardal (Sinapis arvensis L.)’ın mücadelesinde tatmin edici kontrol (% > 90) sağlayan, minimum metribuzin dozları belirlenmiştir. Denemeler kontrollü sera koşullarında, plastik saksılar içerisinde yetiştirilen yabancı -1 otlara metribuzinin önerilen dozunun