The production of sesame (Sesamume indicum L.) is affected by inappropriate agronomic practices, weather uncertainties and diseases outbreaks. Bacterial blight (Xanthomonas campestris pv. sesami) disease is a major constraint across the sesame growing areas of Western Tigray. A field experiment was conducted on farmer’s field at Dansha (Kebabo) to determine the effect of four planting densities on bacterial blight disease development, seed yield, and yield components of sesame during 2018 cropping season. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. The highest (70.58%) and least (55.43%) disease severity were recorded from plot planted with 666,666 and 80,000 plants/ha respectively. Maximum seed yield (428.3 kg/ha) was obtained from 250,000 plants/ha due to efficient utilization of nutrients as well as higher plant population, and it shows that seed yield per unit area depends not only on the severity of disease, efficient utilization of nutrients; but also on the number of plants per unit area. Thus, it could be concluded that maximum yield with minimum level of disease severity could be obtained with planting density ranging from 124,444 to 250,000 plants/ha and farmers should avoid high plant populations in areas with bacterial blight disease problems.
Keywords: Bacterial blight, disease development, grain yield, planting densities, Percentage severity index