Brevipalpus (Tenuipalpidae) and orchid fleck virus (OFV) in South Africa: what do we know?

Abstract

Certain species of Brevipalpus (Trombidiformes: Tenuipalpidae) are able to transmit viruses of the citrus leprosis complex, a serious non-systemic disease of citrus. This disease is endemic to Central and South America, and is characterised by necrotic lesions with chlorotic halos on twigs, leaves and fruit. Citrus leprosis is caused by two types of RNA viruses: cytoplasmic (CL-C) and nuclear (CL-N). In South Africa, CL-N symptoms were detected in 2018 in citrus orchards in the Sundays River Valley (SRV) of the Eastern Cape (Fig 1), and found to be associated with trees testing positive for orchid fleck virus (OFV) (Cook et al. 2019). Mites from this site identified as B. californicus s.l. tested positive for OFV. It is assumed that the entry pathway of OFV virus into South Africa was via the trade of orchid pot plants, and that it was then transmitted to citrus by viruliferous B. californicus. This is the first CL virus-vector association and putative transmission from orchids to citrus identified in South Africa.