Banana bunchy top virus
The Banana bunchy top virus (BBTV) is a circular single-stranded DNA virus (18-20 nm in diameter) that causes Bunchy top in bananas. Although the disease was first reported in the late 1880s1 , the virus itself, which was originally classified as a Luteovirus, was isolated in the late 1980s and reassigned to the Nanoviridae family in the genus Babuvirus2 .
BBTV is not mechanically transmissible, but it can be transmitted locally by the banana aphid Pentalonia nigronervosa or over long distances by infected planting material1 . Transmission by the aphid is in a persistent, non-propagative manner.
Alternative hosts for BBTV have been investigated since the aphid vector colonises numerous plant families including Araceae, Commelinaceae, Musaceae and Zingiberaceae. Australian scientists investigated a range of plant species that are either cultivated, naturalised or indigenous to sub-tropical eastern Australia and are able to sustain feeding by the banana aphid3 . They found that after aphidinoculated with BBTV Alocasia brisbanensis, Alpinia arundelliana, Alpinia caerulea, Alpinia zerumbet, Canna indica, Colocasia esculenta, Hedychium coronarium and Heliconia psittacorum cv. Red Parakeet, none of them became systemically infected. Furthermore, no BBTV was detected in surveys of field plants of Alocasia brisbanensis, Alpinia caerulea, Cannaindica, Canna × generalis, Canna × orchiodes, Colocasia esculenta and Strelitzia reginae found growing in or near banana plantations affected by BBTV. They concluded that non-Musa hosts probably do not play a role as reservoirs of BBTV in Australia.