Pre-emergence chemical weed control in ‘Egusi’ melon ( Citrullus lanatus Thunb. Mansf) in the southern Guinea savanna of Nigeria

Abstract

Field experiments were conducted at the Institute for Agricultural Research Station, Mokwa to evaluate pre-emergence herbicides and their mixtures for weed control in ‘Egusi’ melon ( Citrullus lanatus Thunb. Mansf) during 1979–1981. Chloroxuron and prometryne at 3·0 and 2·0 kg a.i./ha, respectively combined good weed control with high melon yields in the 3 years of the investigation. A mixture of prometryne and alachlor at 1·0 + 1·0 kg a.i./ha which was used during the last 2 years of the investigation also gave effective weed control and high melon yields which were comparable to hoe-weeded checks. Norflurazon at 0·5 kg a.i./ha gave selective weed control only in 1979 at a site that was infested mainly with grass weeds. Other herbicide treatments that showed promise in 1981 included mixtures of either prometryne, chloroxuron or alachlor with chloramben at 1·0 + 1·0, 1·5 + 1·5 or 1·5 + 1·5 kg a.i./ha, respectively. Alachlor and metolachlor at 2·0 kg a.i./ha also resulted in high yields of melons. With ridge planting, one hoe-weeding 3 weeks after sowing resulted in a better melon-seed yield than the other treatments. Yield reductions on untreated plots ranged between 27% and 70% of the potential yield of the crop.