Cucumber Mosaic Virus Associated with Leaf Malformation and Stunting in Adiantum pedatum

Adiantum pedatum (maidenhair fern) is a fern commonly used in landscapes and interiorscapes for its attractive foliage. A. pedatum is quite hardy and under conditions of good soil fertility it can become highly intrusive if left unchecked. Maidenhair fern showing symptoms associated with possible virus infection were collected from the Chadwick Arboretum on the campus of The Ohio State University, Columbus. The leaves of the affected plants were slightly malformed such that the pinnules were arranged irregularly at the pinna. The sequence of the pinnae on the rachis and the general appearance of the rachis were distorted. Overall, the symptoms observed were not as severe as those described by Nienhaus et al. on other species of ferns (1). Viral-associated double-stranded RNA (dsRNA) analysis was used to analyze tissue from symptomatic and asymptomatic plants for evidence of virus infection. Results of dsRNA analysis gave evidence of a possible cucumovirus. There was no evidence of dsRNA in the asymptomatic tissue. Symptomatic tissue was subsequently tested for cucumber mosaic virus (CMV) with a direct antibody sandwich, enzyme-linked immunosorbent assay (ELISA). ELISA results were positive for CMV in symptomatic tissue and negative for CMV in asymptomatic tissue. This is the first report of a virus associated with a disease in A. pedatum. Reference: (1) F. Nienhaus et al. Z. Pflanzenkrankh. Pflanzenschutz 9:533, 1974.