Abstract

Bacterial blight is a serious disease affecting green beans (Phaseolus vulgaris L.), impacting all growth and yield parameters and potentially causing a yield loss of about 40%. Inadequate information exists on the evaluation of nitrogen fertilizer potential on bacterial blight diseases in green bean cultivars. The aim of this study was to assess the potential of nitrogen fertilizer in managing bacterial blight disease in green bean varieties to improve growth and yield. Three bean varieties (Cora, Dolly, and Local Black Green Beans) were planted in the field using a completely randomized block design with twelve treatments and three replicates. Fields were treated with nitrogen fertilizer at different concentrations of 30 and 60 g, and subsequently treated with rhizobium inoculants, except in the control field where no treatment was applied. Data for disease incidence, disease severity and yield parameters were collected. Pathogenicity assessment was conducted in the greenhouse by inoculating healthy plants with a bacterial isolate (2 × 10⁴ spores/ml) and measuring the lesion diameter. A significant difference (p ≤ 0.05) was observed in disease incidence, severity, and yield parameters across the different treatments. The highest average number pods per plant of 21 and lowest mean disease severity of 32.6% was recorded in local black green bean variety treated with rhizobium (bacteria) inoculant. This indicates that the application of rhizobium inoculant can be the best management option for controlling bacterial blight disease in all three bean varieties studied.

Key words: Bacteria blight disease, nitrogen fertilizer, green beans varieties.