Detection of two viruses infecting Narcissus by enzyme-linked immunosorbent assay

The enzyme-linked immunosorbent assay (ELISA) proved sufficiently reliable to detect narcissus tip necrosis virus (NTNV) and arabis mosaic virus (AMV) in Narcissus leaf material provided it was of the right age. Similar trends in virus concentration in leaf samples were indicated by ELISA reactions for both viruses, with highest levels at the start of growth, a decrease during flowering, followed by an increase before levels fell as leaves died. Leaf tip samples consistently provided the highest ELISA reactions at all stages and testing was more reliable from outer, older leaves than inner, younger ones. Best samples for ELISA detection of both viruses were from the tips of older leaves early in the growing season.