To assess the phenotypes of R. solanacearum, isolates collected from field, biovars and races of the isolate were determined. The biovar of all seven groups of R. solanacearum isolates obtained from both eggplant and tomato were identified by utilization of disaccharides and of hexose alcohols. The result ofthe biovar test showed that all seven groups of R. solanacearum isolates oxidized disaccharides (sucrose, lactose, maltose) and sugar alcohols (manitol, sorbitol and dulcitol) within 3–5 days (Table 3).The oxidation reaction was indicated by a change in colour.The results revealed a change from a blue to a yellow colour, indicating the oxidization of sugars by bacterial isolates.Therefore, all groups of R. solanacearum isolates belong to biovar III, as shown in Table 3. On the other hand, all the control plates of different sugars and sugar alcohols remain unchanged.