Update on the situation of Phyllosticta citricarpa in Tunisia
Phyllosticta citricarpa (citrus black spot - EPPO A1 List) was first confirmed in Tunisia in 2019 in the Governorate of Nabeul. Official measures have been applied (EPPO RS 2019/141). A survey was conducted from January to July 2021 to assess the presence of P. citricarpa in 11 citrus production regions in the north-eastern part of Tunisia. The survey was conducted in 50 citrus orchards (12 orange (Citrus x aurantium var. sinensis) orchards and 38 lemon (C. x limon) orchards) located in the area of Nabeul, and in the area of Sousse (Bouficha, Sidi Bou Ali and Chott Mariem). The surveyed orchards were not selected randomly by the extension officers but based on the likelihood of disease presence. Symptoms of citrus black spot were observed in 29 orchards in the area of Nabeul in all regions visited (3 in Menzel Bouzalfa, 4 in Benikhaled, 1 in Soliman, 14 in Bouargoub, 2 in Grombalia, 2 in Nabeul, and 1 in Dar Chaben El Fehri), and 2 in the area of Sousse (only in Chott Mariem). Symptoms were observed on fruits, twigs, and leaves in the most affected region, Bouargoub, while only fruit and leaf symptoms were observed elsewhere. Affected fruits showed symptoms resembling hard spot and false melanose lesions. Symptoms mainly affected mature fruits but were also observed on immature fruits.
The results of the survey showed a high disease incidence in the region of Bouargoub, the main lemon production area in Tunisia. Moderate disease incidence was observed in the neighbouring regions, whereas low disease incidence was detected in the region of Soliman.
The situation of Phyllosticta citricarpa in Tunisia can be described as follows: Present, not widely distributed.
Sources
Benfradj N, Mannai S, Jeandel C, Boughalleb‐M'Hamdi N (2024) Geographic distribution, prevalence, and incidence of citrus black spot caused by Phyllosticta citricarpa in Tunisia. Journal of Phytopathology 172(2), e13292.