Cause Five different viruses have been reported to infect cannas including bean yellow mosaic virus (BYMV), canna yellow mottle virus (CaYMV) , canna yellow streak virus (CaYSV), cucumber mosaic virus (CMV), and tomato aspermy virus (TAV). Cannas from the PNW positive for potyvirus (BYMV and/or CaYSV) and CaYMV have been diagnosed by the OSU Plant Clinic. CaYSV and CaYMV are common worldwide and affect plant health. Although specific vectors have not been determined, most of these are generally aphid-transmitted.
Symptoms CaYMV - Mottling, general yellowing, and veinal chlorosis have been reported. Necrotic leaf stippling has also been observed in the OSU Plant Clinic.
Potyvirus (BYMV and/or CaYSV) - In green-leaf cultivars, potyvirus infection produced mosaic and necrotic symptoms. Cultivars Burning Ember and Wyoming have red/green foliage where the red pigmentation was reduced in infected plants. Other symptoms reported include flecking, mosaic, leaf streaking and necrosis, which in severe cases render plants unsaleable.
Coinfection of canna with both CaYSV and CaYMV had symptoms that progressed from a mild mottling to a mosaic and necrosis along the veins and the leaf lamina.
Virus infection in stripped cultivars results in a messy pattern made of wide, irregular stripes and spots rather than the normal steady pattern of narrow stripes.
Cultural control
- Avoid the propagation and distribution of symptomatic plants.
- Purchase only virus-tested (and found to be free of all known viruses) certified stock.
- Remove and destroy infected plants.
- Use a balanced bedding plant fertilizer, maintain EC from 1.0 to 2.56 and a pH of 6 to 7.5.
References Pappu, H.R., Druffel, K.B., and Eastwell, K.C. 2008. Canna yellow mottle virus in Canna spp. in Washington state. Plant Disease 92:1136.
Rajakaruna, P., Shafiekhani, M., Kim, T., Payton, M., Chauhan, R., and Verchot, J. 2014. Production of discernible disease phenotypes in Canna by five plant viruses belonging to the genera Potyvirus, Cucumovirus and Badnavirus. Plant Pathology 63:821-830.