Efficacy of Sequential Applications of Pendimethalin 500 EC (Pendimight®) and Oxyfluofen 240 EC (Harris®) for Weed Control in Direct Seeded Onion (Allium cepa L.) in Sudan

Abstract

A field study was carried out to evaluate the efficacy of pendimethalin 500 EC (trade name: Pendimight®) and oxyfluorfen 240 EC (trade name: Harris®) to control weeds in direct-seeded onion (Allium cepa L.). Pendimethalin and oxyfluorfen were applied solely at reduced rates (1.35 and 0.17 kg a.i. ha-1), and at the recommended rates (1.8 and 0.25 kg a.i. ha-1) as pre-and post-emergence herbicides, respectively. Both herbicides were also applied sequentially at the same doses. Ten weeks after sowing (WAS), the application of pendimethalin alone provided better weed control (62% - 65%) than oxyfluorfen alone (33% - 43%) when they were applied at the lower and recommended rates, respectively. Sequential applications of the two herbicides as pre-and post-emergence herbicides, outperformed applications of the two herbicides alone, and resulted in the best weed control (79% to 85%), lowest weed dry weight (18.35 to 35.60 g.m-2), significantly increased plant height and the number of leaves per plant, and resulted in a ten-fold higher onion yield (24.64 to 26.37 t. ha-1) compared with the Un-weeded control (2.27 t. ha-1). There were no significant differences observed between the treatments on the emergence (%) of onion seeds and the survival of onion seedlings. Sequential applications of pendimethalin and oxyfluorfen is a promising techniques for weed control in direct-seeded onions in Sudan.