Epidemiology
CTV is a virus that is limited to the phloem tissues of its host. It is transmitted semi-persistently by vectors that penetrate the phloem to extract sap, mostly the aphid species that colonize the crop. The brown citrus aphid is considerably more efficient at transmitting the virus than are other aphids that infest citrus. In Florida, it has been shown to be from six to twenty five times as efficient as Aphis gossypii, the most efficient vector found in the state before the introduction of the brown citrus aphid prior to 1995. This efficiency is enhanced by the narrow host range of the brown citrus aphid and its tendency to produce winged forms in order to colonize new growth. A. gossypii has a much wider host range, including hundreds of plant species in Florida, and the transmission of the virus is blocked when it feeds on a different host.
Read more about this topic: Citrus Tristeza Virus