First report of citrus leprosis in South Africa
In South Africa, symptoms resembling those of citrus leprosis disease (EPPO A1 List) were observed in May 2018 in the Eastern Cape province. Citrus leprosis N dichorhavirus (CiLV-N) was detected on 2 sweet orange (Citrus sinensis, Valencia and Navel type) trees in the Addo area (municipality of Sundays River Valley, Sarah Baartman District). The virus was then also detected on another farm in the Gamtoos River Valley. For the moment, the pest status has not been determined by the NPPO of South Africa.
The situation of citrus leprosis disease in South Africa can be described as follows: Present, only in some areas (first found in 2018 in the Eastern Cape province).
EPPO note: Citrus leprosis disease can cause severe defoliation, girdled limbs, premature fruit drop, twig dieback, reduction in both fruit quality and yield, as well as tree death. It is a complex disease, transmitted by mites belonging to the genus Brevipalpus. Disease symptoms are associated with two taxonomically distinct classes of viruses, and at least 5 different viruses:
- positive-sense RNA and cytoplasmic viruses: Citrus leprosis virus C (Cilevirus, CiLV-C), Citrus leprosis virus C2 (Cilevirus, CiLV-C2) and Hibiscus green spot virus 2 (Higrevirus, HGSV-2);
- negative-sense RNA and nuclear viruses: Citrus leprosis virus N (Dichoravirus, CiLV-N), Citrus necrotic spot virus (Dichoravirus, CiNSV).
Sources
IPPC website. Official Pest Reports – South Africa (ZAF-51/2 of 2019-12-17) First detection of Citrus leprosis-N in South Africa. https://www.ippc.int/en/countries/south-africa/pestreports/2019/12/first-detection-of-citrus-leprosis-n-in-south-africa/