Abstract

Field trials were conducted in 2006 and 2007 cropping seasons at the University of Maiduguri Teaching and Research Farm located in Maiduguri (11°50’N; 13°10’E), Nigeria, to evaluate the effect of different pre-emergence herbicides on weed infestation and productivity of sesame (Sesamum indicum L.) The experiment consisted of 22 treatments, which included 4 different pre-emergence herbicides applied at 5 rates each namely butachlor, metolachlor, diuron and pendimethalin at 0.5, 1.0, 1.5, 2.0 and 2.5 kg a.i./ha, weeding at 3 and 6 weeks after sowing (WAS) and a weedy check. The treatments were laid out in randomized complete block design (RCBD) replicated 3 times. Results showed that diuron at 1.5 to 2.5 kg a.i./ha produced significantly (P<0.05) the least weed cover and dry matter at 3 and 6 WAS, which was comparable with two-hoe-weedings at harvest. Both butachlor at 2.0 kg a.i./ha and metolachlor at 1.5 kg a.i./ha produced significantly (P<0.05) low weed cover score and weed dry matter, which were comparable with the least weed cover score in both trials and their combined means at harvest. Among the herbicides tested, butachlor at 2.0 kg a.i./ha and diuron at 1.0 kg a.i./ha produced significantly (P<0.05) the highest grain yield in 2006, while metolachlor at 1.5 kg a.i./ha produced significantly (P<0.05) the highest grain yield in 2007 and the combined means. For effective weed control and higher yield, metolachlor at 1.5 kg a.i./ha and butachlor at 2.0 kg a.i./ha are recommended as an alternative to two hoe-weedings at 3 and 6 WAS for the production of sesame in the Sudan Savanna zone of Nigeria.

Key words: Pre-emergence herbicides, weed infestation, productivity, sesame, savanna, Nigeria.