Chemical Weed Control in Garlic (Allium sativum L.) in Dongola Locality, Northern State, Sudan

Abstract

A herbicides experiment was conducted during two consecutive winter seasons (2011/2012 and 2012/2013) at the demonstration farm of the Faculty of Agricultural Sciences- El Selaim-Dongola University, to determine the magnitude of yield losses due to weed competition and to evaluate the activity and selectivity of the pre-emergence herbicides oxyfluorfen as two formulations (Pilargola 20% EC and Hadaf 24% EC) each at 0.24, 0.30 and 0.36 kg. a.i/ha; and pendimethalin (Stomp 500 EC) at 1.2, 1.5 and 1.8 kg.a.i/ha, in controlling weeds in garlic. Weeded and un-weeded checks were included for comparison. The weed flora in the experimental site consisted of grassy and broad-leaved weeds. The two formulations of oxyflurofen and pendimethalin at their all rates gave consistent and excellent control of graminae weeds throughout the growing season. The two formulations of oxyflurofen gave satisfactory control of broad-leaved weeds, while pendimethalin displayed poor to moderate activity. The best grassy and broad-leaved weeds control was achieved by the herbicide oxyflurofen as Hadaf. A significant weed controlwasachievedin terms of total weed biomass reduction with all herbicides treatments. The better total weed biomass reduction was achieved by the highest rate of pendimethalin (1.8 kg a.i./ha). In general, the herbicides had an excellent and lasting effect on the control of weeds, but the performance of these herbicides was greatly affected by the presence of the resistant weeds including Cynodon dactylon (L.) Pers., Cyperus rotundus L., Convolvulus arvensis L. and Rhynchosia memnonia (Del.) DC. Combined analysis of both winter seasons data indicated that unrestricted weed growth significantly reduced garlic yield by 36.08%, while herbicides treatment significantly increased garlic bulb yield, and the best garlic bulb yield was achieved by the highest rate of pendimethalin at 1.8 kg. a.i/ha, and gave bulb yield comparable to weed free full season treatment. Based on these results, it can be concluded that, the effectiveness of the herbicide pendimethalin at 1.8 kg. a.i/ha, against weeds and its high selectivity in garlic, make this herbicide possible candidate for the control of weeds in garlic in the Northern State, Sudan.