In the extensive investigation into the extent of the outbreak of the brown rot bacterium Ralstonia solanacearum, the Dutch Food Safety Authority (NVWA) identified contamination at three rose growers. Suspicious samples have been taken from two other plant growers and two rose growers. More companies are included in the investigation. The bacterium is known as a pathogen in potatoes and poses no danger to public health.
The reason for the research is the discovery of brown rot bacterium at two rose growers in the province of South Holland in August 2015. At the rose growers 1 variety of the brown rot bacterium was detected. This is a different variety than the race that is known from potato diseases in the Netherlands (variety 3). Roses were hitherto not known as a host of the brown rot bacterium.
Investigation NVWA
Right now the NVWA is conducting further investigation at three plant breeders and six growers into the extent and source of the contamination. Controllers have taken samples from the plants and the water system of these companies. These samples are examined at the National Reference Laboratory of the NVWA. This investigation may take several weeks before a infection is identified. In the short term the NVWA will also be investigating a few nurseries. Furthermore, the Dutch buyers of the growers will be included in the investigation. This investigation is expected to take a while. At this moment the NVWA is collecting information about deliveries to other countries. When necessary they will be informed.
Measures
Until all the samples are analysed, no propagating material from the relevant plant breeders may be marketed. Affected growers may only bring cut flowers on the market when the NVWA has determined that no symptoms of brown rot can be seen on the plants.
If, according to the laboratory of the NVWA, plants or the water system of a producer or grower is infected with brown rot, they must destroy the infected plants and clean and disinfect all materials and surfaces that may have been in contact with the bacterium. This is done under the supervision of the NVWA.