The European and Mediterranean Plant Protection Organization (EPPO) has issued an alert confirming that the Tunisian authorities have officially declared an area infected with Phyllosticta citricarpa, the fungus that causes black spot. We are talking about 2,000 hectares in the Nabeul Governorate; a citrus growing area in the northeast of the country. This proves that the climatic conditions of the Mediterranean basin are not an impediment to its establishment.
Following the interception by French border authorities of up to seven shipments of citrus from Tunisia with the presence of this fungus, an investigation was launched in March and April by the Tunisian phytosanitary authorities. This confirmed that the infected batches came from the municipalities of Beni Khalled, Bouargoub and Menzel Bouzelfa. The origin of this outbreak is unknown, but it is suspected that infected plant material has been illegally brought to this area (the importation of citrus plants for planting is prohibited in Tunisia), and that the floods recorded in this region in September 2018 facilitated the spread of the fungus.
Emergency measures are being implemented together with the parties involved (producers, technical institutes, researchers, etc.). A chemical control program, which includes the registration of additional fungicides, will be enforced in the area of the outbreak. Furthermore, a monitoring program is being developed, with samples to be collected and analyzed using molecular methods in order to delimit the extent of the disease (to date, 110 analyses have been requested). There will also be awareness-raising activities intended to train professionals and prepare them to recognize the symptoms and to apply control measures.
The Tunisian authorities are developing a three-year strategic plan to keep the P. citricarpa under control. This includes new regulations affecting the movement and certification of citrus plants; greater surveillance in all citrus cultivation areas, mainly in the places where plants are produced for the planting; improvements in the infrastructure of quarantine laboratories; the application of a control program for the disease, with cultural and chemical methods, in an area of 10,000 hectares worth 1.7 million Euro; the launch of awareness campaigns aimed at producers and the general public; and the development of research activities on epidemiology, biology and disease control, with a budget of 30,000 Euro per year.
For the Citrus Management Committee (CGC), an association that represents the main Spanish private exporters, the finding should force the European Commission to adopt immediate measures and enforce stricter regulations on the citrus fruits from the EU's main off-season suppliers: South Africa, Argentina, Brazil and Uruguay.
In addition, it has asked the European Commission to include this fungus in the list of priority quarantine pests, given the severity of its economic, social and environmental impact, since it has been left out of the provisional list, published recently. “The sudden elimination of CBS (Citrus Black Spot) from this list, coinciding with the first suspicions, now confirmed, that the fungus is already present, for the first time, on the other side of the Mediterranean, suggests that the EC might be tempted to try avoiding the co-financing of the necessary eradication measures and the payment of compensations to the growers affected by a possible outbreak of this fungus,” denounced the president of the CGC, Manuel Arrufat.