A combined indexing and budwood propagation method for citrus

Several budwood-transmitted citrus diseases, including citrus tristeza virus, citrus psorosis, citrus impietratura and a range of citrus viroids, were tested both visually and biochemically on a combined indicator (CInd) plant consisting of an Alemow (Citrus macrophylla) rootstock grafted with Etrog citron (C.medica) and Sour orange (C.aurantium) or Sweet orange (C.sinensis) buds. Indexing on CInd plants is economical for limited testing space; an additional advantage is that, by collecting budwood directly from the CInd plants, the risk of diagnostic failure due to uneven pathogen distribution in the budwood source tree is considerably reduced.