Integrated Management of Striga hermonthica on Sorghum

The phytoparasite, Striga hermonthica (Del.) Benth., is a major biotic constraint to cereals production in sub-Saharan Africa. An experiment was conducted to investigate the effects of nitrogen and the herbicides triclopyr, chlorsulfuron and their combination on Striga incidence and sorghum (cv. Wad-Ahmed) growth and yield. The present research was undertaken at the College of Agricultural Studies, Sudan University of Science and Technology. Treatments were arranged in Complete Randomized Block Design (CRBD). All treatments at 45 days after sowing (DAS), reduced Striga emergence albeit not significantly as compared to the control. At 60 DAS, untreated control (3 plants/ m2) sustained the highest Striga emergence significantly as compared to other treatments. Sorghum height, irrespective of the observation date did not show significant differences between treatments. At 60 DAS, triclopyr at 0.49 and 0.73 kg a.e ha-1 supplemented with nitrogen at 43.8 kg ha-1, increased sorghum height by 11.9 and 9.4%, respectively, as compared to untreated control. Chlorsulfuron at 2.38 g a.i ha-1 when supplemented with nitrogen, irrespective of rate, caused considerable decrease in peduncle length by 48.7-51.3%, respectively when compared to the control. However, triclopyr at 0.73 kg a.e. ha-1 alone or in combination with nitrogen at 87.6 kg ha-1 had no effects on peduncle length when compared to the untreated control. All treatments significantly increased head length over the untreated control. Chlorsulfuron at the highest dose when combined with nitrogen at the highest rate resulted in the highest increase in head length 27.6%. All treatments increased head circumference over the untreated control albeit not significant. Triclopyr at 0.49 and 0.73 kg a.e. ha-1, in supplementation with nitrogen at 87.6 kg ha-1 displayed the highest increase in straw weight 30.2-39.6%, respectively. Triclopyr at 0.49 kg a.e. ha-1, tank mixed with chlorsulfuron at 1.19 g a.i ha-1 and supplemented with nitrogen at 87.6 kg ha-1 caused an increase in straw weight by 5.7-9.4% over the untreated control.

Conclusion: Herbicides examined when applied subsequent to nitrogen provide efficient packages for Striga management than when applied alone or tank mixed with each other.