Update on the situation of Pseudomonas syringae pv. actinidiae in Switzerland
In Switzerland, Pseudomonas syringae pv. actinidiae (EPPO A2 List) was detected for the first time in June 2011 in the Canton of Geneva in a small kiwifruit commercial orchard shortly after planting (EPPO RS 2011/168). In 2015, the bacterium was found in a commercial orchard in the Canton of Vaud and a nursery in the Canton of Thurgau (EPPO RS 2015/132). Both findings could be traced back to a lot imported from Italy in May 2013 and distributed by the nursery. Although eradication measures were taken at both sites, the bacterium was detected again in June 2016 on asymptomatic plants in the same orchard (in a plot of 0.6 ha neighbouring the one of the initial finding). Eradication measures were taken and included the uprooting and destruction of all kiwifruit plants in the infested plot. In addition, P. syringae pv. actinidiae was detected in May 2016 on kiwifruit plants in 2 private gardens (Canton of Fribourg) and in a garden centre (Canton of Ticino). Infected plants had been delivered by a second nursery in close proximity to the aforementioned nursery in Canton of Thurgau. The two nurseries were exchanging kiwifruit plants. In the same year (2016), plants originating from the second nursery were also found to be infected (following a notification from Germany). Investigations revealed that a mother plant (initially grown in Italy and imported in 2014) in the first nursery was the most likely source of infection. In May 2017, P. syringae pv. actinidiae was found during an official survey in a private garden in the vicinity of the orchard affected by the outbreaks in 2015 and 2016 (Canton of Vaud). On every site, eradication measures were immediately taken according to the Swiss legislation (equivalent to Implementing Decision 2012/756/EU) to eradicate the disease. These measures included the preventive destruction of all kiwifruit plants and disinfection of the nurseries in the Canton of Thurgau in 2016. Surveillance for P. syringae pv. actinidiae is ongoing.
The pest status of Pseudomonas syringae pv. actinidiae in Switzerland is officially declared as: Transient: actionable, under eradication
Sources
NPPO of Switzerland (2017-07).