We have sequenced the complete genome of an isolate of Banana streak virus from banana cv. 'Mysore' and show that it is sufficiently different from a previously characterised isolate from cv. 'Obino l'Ewai' to warrant recognition as a distinct species, for which the name Banana streak Mysore virus (BSMysV) is proposed. The structure of the BSMysV genome was typical of badnaviruses in general, although ORF I had a non-conventional start codon. Evidence that at least part of the BSMysV genome is integrated in the B genome of cultivated Musa is presented and transmissibility by the mealybug Planococcus citri also demonstrated.