Situation of Ralstonia solanacearum in the Netherlands - harvest 1996
A preliminary report of the situation of Ralstonia (Pseudomonas) solanacearum (EPPO A2 quarantine pest) concerning the 1996 potato harvest in the Netherlands appeared in the EPPO RS 96/182. An update of the situation has recently been sent to the EPPO Secretariat. In the Netherlands, during the 1996 season, all seed potato lots from one place of production have been tested for the bacterium before a plant passport or a phytosanitary certificate was issued and marketing allowed. Sampling and testing was carried out from mid-August to the end of November. Approximately 58,000 samples were tested from 3,100 seed potato growing farms. Infections with R. solanacearum were found on nine farms. On each farm, only one potato cultivar was infected. Seven of these farms were growing seed potatoes. Measures have been taken to prevent spread of the bacterium from all infected farms. Concerning the farms found infected during the 1995 season, which were allowed to grow ware potatoes, all potato lots of the 1996 season were tested and no infection was detected.
To determine the extent of contaminated surface water and infected Solanum dulcamara plants, studies were started all over the Netherlands with emphasis on potato-growing regions in spring 1996. In several of the potato-growing regions, contaminations of surface water and/or S. dulcamara were detected. Areas with contaminated surface water have been demarcated. For potato lots from these demarcated areas posing a risk (use of surface water), only a controlled distribution as ware potatoes was allowed.
In addition, an infection of R. solanacearum was found in one tomato glasshouse. The infection was due to the contamination of the surface water used for irrigation. However, irrigation of tomato crops with surface water is not a common practice in the Netherlands. This single glasshouse infestation has been eradicated by destroying all plant material and rockwool, and disinfecting the irrigation system, tools and premises.
Sources
Plant Protection Service of the Netherlands, 1997-01.