Tomato yellow leaf curl virus (leaf curl).

Abstract The wide global distribution of tomato crops and the dramatic outbreaks of the populations of the TYLCV vector, the whitefly Bemisia tabaci, led to a pandemic of this devastating disease. The virus probably arose in the Middle East between the 1930s and 1950s. Its global invasion began in the 1980s after the emergence of two strains: TYLCV-IL and TYLCV-Mld. The long-distance transportation of viruliferous whiteflies contaminating commercial shipments of tomato seedlings and ornamentals is probably the major reason for the virus pandemic (Caciagli, 2007). Sequence analyses allowed Lefeuvre et al. (2010) to trace the history of TYLCV spread. For instance, TYLCV-IL has invaded the Americas at least twice, once from the Mediterranean basin in 1992-1994 and once from Asia (a descendant of imported Middle Eastern TYLCV) in 1999-2003. As a result the estimated losses caused by TYLCV reached about 20% of tomato production in the USA, and 30-100% in the Caribbean Islands, Mexico, Central America and Venezuela. Therefore several countries (Australia, EU) have established severe quarantine measures to control the whitefly vector.