Creeping bugleweed (Ajuga reptans L.) is a perennial ornamental commonly grown as a ground cover in temperate climates. Commercial samples of the A. reptans cultivars Royalty, var. Atropurpurea Bronze, Bronze Beauty, and Burgundy Glow showing mosaic and ringspot symptoms were tested for the presence of virus infection by direct antibody sandwich enzyme-linked immunosorbent assay (ELISA) and viral-associated double-stranded (ds) RNA analysis. Cucumber mosaic cucumovirus (CMV) was detected by ELISA and dsRNA analysis in symptomatic samples of all cultivars tested. ELISA values were considered positive if the absorbance values were twice the negative control. Negative control values were established with asymptomatic tissue of the cv. Bronze Beauty. Tobacco streak ilarvirus (TSV) was detected only by ELISA in symptomatic samples of all cultivars except Royalty. No dsRNA suggestive of TSV was detected. Alfalfa mosaic virus (AMV) was detected by ELISA and dsRNA analysis in symptomatic samples of all cultivars tested except Royalty and var. Atropurpurea Bronze. dsRNA analysis also indicated the presence of a low molecular weight, possible satellite (sat) RNA associated with all symptomatic and asymptomatic Royalty and var. Atropurpurea Bronze plants tested. Northern (RNA) blot analysis with a digoxigenin-labeled full-length clone of the (S) CARNA-5 (-) CMV satRNA (ATCC no. 45124) confirmed that the low molecular weight RNA associated with the Royalty and var. Atropurpurea Bronze cultivars was indeed CMV satRNA. Only AMV has been previously reported in A. reptans in the United States (1). This is the first report of CMV and its satRNA, as well as TSV, in A. reptans in the United States.
Reference: (1) W. T. Schroeder and R. Provvidenti. Plant Dis. Rep. 56:285, 1972.
