Within a comprehensive study for the assessment of the sanitary status of the Lebanese citrus industry, surveys were conducted in the main citrus-growing areas of the country. Commercial groves and nurseries were surveyed for symptoms of citrus virus and virus-like diseases and budwood and leaf samples were collected for indexing. Tests were carried out by ELISA for citrus tristeza virus (CTV), citrus psorosis virus (CPsV) and Spiroplasma citri , the stubborn disease organism. Molecular

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... ation was used to index for the citrus exocortis viroid (CEVd) and the citrus cachexia viroid (CCaVd) and biological indexing was used to detect psorosis, oak-leaf patterns and infectious variegation. Concavities and bark scaling were widely observed in the trunks of Washington navel, Shamouti and Valencia oranges. Leaf symptoms of oak-leaf patterns, mottling, ringspot and curling were also seen on field trees, sometimes associated with bark disorders. Symptoms of cachexia were observed in mandarins and stubborn symptoms were evident on sweet orange. No decline or clear-cut tristeza symptoms were observed in the field. ELISA indexing showed 66 out of 4,497 trees to be CTV-infected; 50 out of 557 trees were positive for S. citri and 48 out of 186 trees infected by CPsV. Of 186 trees indexed by graft-transmission, approximately 24% produced psorosis-like symptoms, 10% produced oak-leaf patterns and 7% showed infectious variegation symptoms. All the CTV isolates induced strong vein clearing and cupping in Mexican lime leaves and mild stem pitting in the wood. CCaVd was detected in 62 out of 186 samples tested (33%), and CEVd in 61 samples (32.8%).