Are there Brevipalpus mites (Acari, Tenuipalpidae) transmitting Citrus Leprosis Virus on Western Mediterranean and Macaronesian citrus crops?

Abstract: Flat mites (Acari: Tenuipalpidae) are exclusively phytophagous and include several pest species of economic importance, all of them belonging to the genus Brevipalpus. In the Americas some Brevipalpus species are vectors of plant viruses on tropical fruit crops and ornamental plants, being responsible for the transmission of Citrus Leprosis Virus (CiLV). For a long time, it was thought that B. phoenicis (Geijskes) was the vector of CiLV; however, a recent taxonomic revision using new taxonomic characters has split this species into seven different taxa and the transmission of CiLV is now attributed to B. yothersi Baker and B. californicus sensu lato. Although Brevipalpus species are present on trees in the Mediterranean, CiLV has never been reported from this region. The objective of the present work was to revise all the Brevipalpus mites collected on citrus in Spain and Middle Atlantic Islands from 1982 to 2017 which are deposited in the Acari Collection of the Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, in order to identify this biological material and to look for the species responsible of virus transmission. Seven species were identified, with B. californicus sensu stricto, B. azores Beard & Ochoa and B. californicus species B being the most abundant species. Brevipalpus californicus sensu stricto and B. californicus species B were predominant in the peninsular citrus orchards, while B. azores was the main species on Canary Islands and Azores Islands. Brevipalpus yothersi, the main vector of CiLV, was not found in the material examined, which could explain the absence of the disease in the Western Mediterranean countries.