EFSA evaluates citrus black spot

The European Food Safety Authority’s Plant Health (PLH) Panel has published a scientific opinion on Guignardia citricarpa Kiely, a fungus that causes citrus black spot (CBS) disease. The Panel concluded that climatic conditions would not be a barrier to G. citricarpa establishing itself in European citrus growing areas. The European Commission asked EFSA for scientific advice on CBS following a request by South Africa to review current EU phytosanitary regulations relating to the export of citrus fruit from South Africa to the European Union.

The opinion was based on the evidence provided by South African authorities and additional data collected. G. citricarpa, is currently not present in Europe and a series of phytosanitary measures are in place to help protect Europe’s citrus crops from CBS.The Panel also looked at the likelihood of an introduction of CBS to Europe through infected fruit, and the appropriateness of the current control measures.

South African authorities are of the opinion that the citrus-growing areas of Europe do not have a climate suitable for the CBS disease to take hold, and therefore the current EU phytosanitary measures regarding the import of fresh citrus fruit from South Africa should be revised. G. citricarpa, attacks a wide variety of citrus species causing black spots and blemishes making them unsuitable for sale.

The PLH Panel pointed out that the assessment of climatic suitability provided by South Africa was based on the use of specialised software which has many limitations for the evaluation of organisms such as G. citricarpa. For example the software used does not capture climatic factors of short duration, such as leaf wetness that play an important role in the lifecycle of this fungus.

The Panel disagreed with the view of South African authorities that it is unlikely that the import of fruit could lead to CBS establishing itself in Europe. The Panel concluded that the harmful organism could enter citrus-producing areas in Europe and this would be more likely especially if the symptoms of the disease could not be easily seen on the fruit, making it difficult to intercept them at EU borders. Once introduced, G. citricarpa can easily establish itself in Europe as there are many susceptible citrus host plants.

The Panel also examined the existing control measures and concluded that generally they are not fully effective in eliminating the likelihood of the introduction of the disease from South Africa. The risk of CBS could however, be reduced by combining pre-harvest and post-harvest treatments of citrus fruit at the country of origin. An alternative option suggested by the Panel would be to adopt different measures for controlling end use and the distribution of the fruit in the citrus-producing and the non citrus-producing areas in Europe.