Canna (Canna indica) is an important nursery/landscape plant in Washington State with several nurseries producing canna plants for wholesale and retail businesses. Canna plants showing symptoms such as mottling, general yellowing, and veinal chlorosis were found to be widespread (40% symptomatic plants in a nursery of more than 2,000 plants) in Grant County, WA in September 2007. Symptomatic leaves from five plants of each of the following cultivars were tested: Richard Wallace, Crimson Beauty, Wyoming, Petoria, Pink Beauty, Robert Kemp, and Black Knight. Electron microscopic examination of leaf-dip preparations from symptomatic leaves showed badnavirus-like particles of approximately 120 × 30 nm. A badnavirus, Canna yellow mottle virus (CaYMV) (family Caulimoviridae, genus Badnavirus) from canna was first reported from Japan (4) and later in the United States (1,3). Most recently, CaYMV was reported from Italy and the Netherlands (2). Samples were tested for CaYMV by PCR using CaYMV-specific primers, CaYMV-3 (5′- GAC TTC CTG GGT GCA ACA AT -3′) and CaYMV-4 (5′- TCT GTG CAA TCT TGG CGT AG -3′) (2), which produced a 565-bp amplicon. All samples tested gave the amplicon of expected size. The amplicon from one leaf sample from each of the cultivars was cloned and sequenced. Sequence comparisons with those available in the GenBank confirmed that the sequence obtained was that of CaYMV (95% sequence identity). Increased awareness of the prevalence of CaYMV in nurseries and avoiding the propagation and distribution of infected plants are necessary to minimize the further spread of this virus in canna.
References: (1) B. E. L. Lockhart. Acta Hortic. 234:69, 1988. (2) M. T. Marino et al. Online publication. New Disease Reports. http://www.bspp.org.uk/NDR/july2007/2007-08.asp, 2007. (3) M. T. Momol et al. Online publication. doi:10.1094/PHP-2004-0809-01-HN. Plant Health Progress, 2004. (4) S. Yamashita et al. Ann. Phytopathol. Soc. Jpn. 51:642, 1985.
