Biological characterization of Citrus tristeza virus strains in lemon in Tucumán, Argentina

tucumán province is the largest lemon producer in the world, with a production of 1.3 million tons. unfotunality, tristeza disease has been present in argentina since 1930 and is endemic. citrus tristeza virus isolates from the main lemon varieties in tucumán province were biologically characterized on the basis of vein clearing, vein corking, leaf cupping, stunting, stem pitting and other symptoms using standard indicator plants. the lemon varieties were: frost eureka, frost lisbon, limoneira 8a and genoa eeat. the indicator plants used were mexican lime, eureka lemon, duncan grapefruit, pineapple sweet orange and sour orange seedlings, plus ruby blood sweet orange budded on sour orange rootstock. symptoms on each of the indicator plants were rated from 0 (no reaction) to 5 (most severe). a total rating for each isolate was obtained by summing the ratings on each indicator plant. differences among lemon isolates were observed. genoa isolate induced least growth while limoneira isolate induced the most severe stem pitting. little difference was observed between eureka and lisbon isolate.