Garnsey, S.M. - Horticultural Research Laboratory, Federal Research, Science and Education Administration, U.S. Department of Agriculture, Orlando, FL 32803 USA

Gonsalves, D. - Department of Plant Pathology, Cornell University, Geneva, NY 14456, USA (work done while at Univ. of Florida, Agricultural Research and Education Center, Lake Alfred, FL 33850)

Purcifull, D.E. - Plant Virus Laboratory, University of Florida, Gainesville, FL 32611, USA 

Clark, M.F. - East Malling Research Station, Maidstone, Kent, England

An enzyme-linked immunosorbent assay (ELISA) test was used to identify citrus tristeza virus (CTV) in extracts from citrus tissues. Alkaline phosphatase conjugates were prepared with partially purified γ-globulin from antiserum to purified CTV. Citrus tristeza virus was detected quickly in extracts of experimentally inoculated plants kept in various indoor facilities, and in extracts of infected samples collected from the field. The ELISA procedure was equally effective for detection of most common and seedling yellows isolates of CTV from Israel and from Florida. Isolates that produced only mild symptoms on lime (Citrus aurantifolia) ‘Mexican’ indicator seedlings could be detected by ELISA. The virus was detected in various phloem-containing tissues during warm and cold seasons, but was most readily detected from fruit pedicel bark. A test procedure that incorporated composite sampling and mechanical homogenization was developed to index large numbers of field trees.