Risk assessment and reduction options for Ceratocystis platani in the EU

Abstract

Following a request from the European Commission, the EFSA Plant Health (PLH) Panel performed a risk assessment for Ceratocystis platani in the EU with the aim to assess the effectiveness of risk reduction options (RROs) on the basis of the mechanisms of spread identified in the pest categorisation (natural and human-assisted means, including waterways, root anastomosis, contaminated pruning tools, machinery, insects, contaminated insect frass and sawdust). C. platani is a destructive pathogen of Platanus trees, which is currently present in the EU (in France, Greece and Italy). Three scenarios were considered: the current situation (A 0 scenario); the situation without RROs (A 1 ); and the application of additional RROs (A 2 ). The risk of new introductions into the EU of C. platani by means of the main pathways of entry (i.e. plants for planting, wood and machinery, e.g. construction machinery and pruning/cutting tools) is relatively limited, but about 250 times higher for the A 1 scenario compared to the A 2 scenario (median numbers of established populations). The risk of spread from already affected EU regions is higher, but varies depending on the scenario. Machinery is the most important mechanism of long-distance spread. Focusing the additional RROs in A 2 scenario on this mechanism of spreadwhich is not currently regulated -would be an effective way to reduce the likelihood of further spread and thus impacts of C. platani to not yet affected EU regions. The emergency measures applied by the C. platani-affected EU Member States (France, Greece and Italy) could be harmonised and improved. An enhanced programme could be developed which includes surveillance, early detection of the disease foci, effective eradication measures and planting resistant Platanus clones in new plantations in affected areas. Surveillance could also be intensified in the EU MSs not yet known to be affected by the disease.

Ceratocystis platani is killing plane trees in Istanbul (Turkey)

“…It is likely that CSD arrived in Istanbul through spread from another European country and not due to an independent new introduction from North America. Although this view needs to be confirmed with population genetic analyses, the risk for new introductions of C. platani into the EU by the main pathways for entry (plants for planting, wood, construction/terracing/logging machinery and pruning/cutting tools) is regarded as limited (Jeger et al., ), and therefore an independent introduction would have been unusual.…”

“…platani population is clonal (Ocasio‐Morales, Tsopelas, & Harrington, ; Santini & Capretti, ). Although the disease initially spread slowly in Italy, it has now been confirmed throughout the Italian peninsula, in France, Switzerland, Greece and recently in Albania (Jeger et al., ; Tsopelas & Angelopoulos, ; Tsopelas et al., ). Spain is believed to be free of the disease after eradication of infected trees in the country (Jeger et al., ).…”

“…Although the disease symptoms are similar to those of a vascular wilt, the common name of “canker stain” refers to the cankers resulting from infection. The main pathway of spread of C. platani is by human activities, in both urban and rural areas: movement of infected host plants, use of contaminated tools and terracing machinery (Jeger et al., ). In large natural stands where this anthropogenic effect is weaker, the disease is less common.…”

“…Currently, there is no effective chemical or biological control method for CSD (Jeger et al., ). Therefore, control of the pathogen is based on cultural practices and sanitary methods; transmission of the disease can be reduced by the use of healthy plant propagation material, along with immediate removal and destruction of symptomatic plane trees and their neighbours (Panconesi, ), as further spread of the pathogen to nearby trees is known to occur via root anastomosis (Mutto Accordi, ).…”

Emerging forest disease in Europe and North America

“…C. platani is a highly infective pathogen with the potential to cause great impact, but which currently has limited distribution in the three EU Member States, that is, Italy, France and Greece. Following the pest categorisation carried out by EFSA PLH Panel in 2014(EFSA 2014, in which it was proposed to list the pathogen as a Union Quarantine pest, the EC asked for a full pest risk assessment with the aim to develop RROs on the basis of the mechanisms of spread (Jeger et al 2016). Hosts, particularly the most susceptible ones, are widely grown in most of the MSs and the eco-climatic conditions are suitable for the establishment of pathogen in non-infested areas.…”