Ralstonia (Pseudomonas) solanacearum race 3, biovar 2, detected in surface (irrigation) water in Egypt.
The causal agent of potato brown rot, Ralstoniasolanacearum was demonstrated for the first time to be present in surface (irrigation) water in Egypt. The bacterium was identified in both irrigation and drainage canals near to infected fields within 3 potato-growing areas in the delta that were already known to be infected. The bacterium was found in populations of up to 106 colony forming units per litre. No weed hosts such as Solanum dulcamara were found along the canals. The bacterium was not detected anywhere in the desert area. It is concluded that these findings show that irrigation water can play a role in the epidemiology of brown rot disease in Egypt and further studies are necessary to determine its exact role. The use of artesian water in the desert area and avoidance of re-use of irrigation water could be important factors in the avoidance of brown rot problems.