Infections by one or more of Canna yellow mottle virus (CaYMV), Bean yellow mosaic virus (BYMV) and Canna yellow streak virus (CaYSV) cause a range of symptoms in cannas including stunting, distortion and streaking in the leaves and colour ‘breaks’ in the flowers.
CaYMV infects only cannas, but BYMV infects a wide range of plants, including beans, peas, freesias and gladioli. CaYSV is a new virus, found for the first time in the UK in 2007. Newly infected leaves can be expected whenever the plants are growing from mid spring until late autumn.
For more on how these viruses are transmitted, see the Biology section below.