How Is CTV-SP Transmitted?
As with decline isolates, CTV-SP isolates can be
transmitted by budding and grafting. Long distance
movement of CTV-SP to different countries or
different areas within a region is usually via the
movement of the infected budwood or nursery stock.
CTV-SP is also transmitted by several species of
aphids. The brown citrus aphid (Toxoptera citricida)
is considered the most efficient vector, but the melon
aphid (Aphis gossypii) and the spirea aphid (A.
spiraecola) can also transmit the CTV-SP virus. The
patterns of spread vary according to the type of
aphids involved. CTV-SP problem often increases
rapidly after the brown citrus aphid becomes
established in a new area and it seems that CTV-SP
isolates are transmitted more often by brown citrus
aphid as compared to other aphids. CTV can be
transmitted experimentally by stem slash inoculation
of citrus plants, and thus transmission on
contaminated tools in the field is likely.