Effect of Nicosulfuron Mixtures and Time of Application on Peanut (Arachis hypogaea) Cultivars

Field experiments were conducted near Marianna, Trenton, and Archer, FL in 1990 and 1991 to investigate the effect of nicosulfuron mixtures and time of application on five peanut cultivars. Nicosulfuron at 54 g ai/ha was applied alone or in mixture with 2,4-DB at 280 g ai/ha 5 weeks after planting (WAP), 9 WAP, or 5 plus 9 WAP. Injury was greater from early and sequential nicosulfuron applications while a single application 9 WAP typically did not cause significant injury or reduce peanut yield. The 5 WAP and 5 plus 9 WAP applications often caused early visible injury and sometimes reduced peanut yield. When peanut yields were compared, ‘Florigiant’ was the most sensitive cultivar while ‘Southern Runner’ and ‘Valencia’ were more tolerant to nicosulfuron. ‘Sunrunner’ and ‘NC-7’ were intermediate in tolerance to nicosulfuron. In several instances, the addition of 2,4-DB to nicosulfuron reduced initial crop injury and ameliorated yield losses resulting from nicosulfuron applied alone.