Further outbreaks of brown rot of potato (Pseudomonas solanacearum) in the EC (BE, NL)
A first outbreak of brown rot of potato caused by Pseudomonas solanacearum (EPPO A2 quarantine pest) in the EC (UK) had been reported in EPPO Reporting Service 93/031 (1993, No. 2). More outbreaks of the bacterial disease within the EC were now reported from Belgium and The Netherlands.
In November and December 1992 P. solanacearum was detected in the community of Mol (BE) and its environments on some tens of ha of potatoes. Several cultivars have been found to be infected. The pathogen, however, was not found in certified seed potatoes. The exact origin of the limited contamination has not yet been discovered. Belgian authorities have placed the areas concerned under official regulation and will try to eradicate the pest.
In The Netherlands, the disease was found in September 1992 during a routine check of stored potatoes (intended for industrial processing) cv. "Russet Burbank" stored in Reusel. The lot was produced on rented land, located in Belgium, by a Dutch farmer. In December 1992, potatoes cv. "Agria" intended for industrial processing, grown at Leveroy near the Belgium border, were found to be infected with P. solanacearum. Official investigations made clear that the infestation resulted from seed potatoes and that uncertified material was used. Further investigations to trace back the infected seed material and to find the source of this infection are under way. To eradicate the pest the Plant Protection Service of The Netherlands has initiated an extensive control and survey programme. The potato crops found infected by P. solanacearum were destroyed by means of processing under the supervision of the plant protection service and the field in Leveroy where the pest was found has been placed under official notice. For the future, all potato crops in the surrounding communes of Leveroy and Reusel will be identified and mapped. Farmers intending to grow potato crops will have to notify the Plant Protection Service of the intended time of harvest and the harvest will only be allowed under official supervision. Inspections on tubers will be carried out in these areas. The total expected area surveyed in this manner will be 2000 ha. In a more extensive region along the Belgian border with an extent of 3500 ha all potato fields will be surveyed directly after harvest by inspecting waste tubers still present on the fields.
In relation to this recent findings of brown rot of potato in Belgium and The Netherlands Dutch authorities have also informed EPPO that an earlier finding of P. solanacearum took place in 1989. Potatoes infected with the disease were found in storage at Reusel and originated from a Dutch farmer producing this crop on rented land in Belgium. The cv. concerned was "Ottena".
Belgium Plant Protection Service, Brussels (1993-03)
Ministry of Agriculture, The Netherlands (1993-03)