Vector competency of Bevipalpus californicus and Brevipalpus lewisi for citrus leprosis virus-cytoplasmic (CiLV-C) in citrus

Citrus leprosis disease (CL) is economically damaging to citrus production in many regions, causing fruit discoloration, twig dieback, and defoliation, but has not been found in California. CL is caused by several viruses including citrus leprosis virus-cytoplasmic (CiLV-C), and all are vectored by Brevipalpus mites (Trombidiformes: Tenuipalpidae). The viruses are circulative and propagative in the mite, but only infect cells adjacent to feeding sites in the plant. To assess the risk to the California citrus industry, we tested the ability of two native mites, B. californicus (Banks) and B. lewisi (McGregor), to acquire and transmit CiLV-C. We compared their ability to vector this virus with a known CiLV-C vector, B. yothersi (Baker), using the plant Citrus sinensis (L.) Osbeck (MV). Each mite species fed on CL fruit lesions or clean orange fruit (controls) for 24 or 48 hours, then were transferred to healthy orange fruit or MV plants. Mites and plants were tested for CiLV-C by RT-PCR. All three mite species were CiLV-C positive after feeding on lesions, but only B. yothersi continued to be CiLV-C positive after feeding on clean fruit. As expected, B. yothersi and leaf lesions on MV were CiLV-C positive at all time points. B. californicus and B. lewisi were CiLV-C negative at the end of the experiments, no leaf lesions were observed on MV plants, and no plants tested positive for CiLV-C. Together, this indicates that B. californicus and B. lewisi pick up CiLV-C during feeding but do not retain or transmit it.