Introduction and Management of Tomato Yellow Leaf Curl Disease

Tomato yellow leaf curl disease (TYLCD) was reported firstly in tomato (Solanum esculentum) fields, association with outbreaks of the whitefly Bemisia tabaci, in the late 1930s in Jordan valley. Since 1960s, TYLCD has become the most destructive disease of tomato throughout the world. Tomato crops are severely affected by TYLCD and 93-100% yield losses have been recorded in some cases. Infected tomato plants have a few, small fruits and in some cases, flower abscission resulted to the loss of fruits. The viral nature of the disease agent and its transmission with whitefly was proved in 1964. The disease viral agent was then identified and named tomato yellow leaf curl virus (TYLCV) and its genome sequence was determined in the late 1980s. TYLCV is a member of the genus Begomovirus in the family Geminiviridae, which includes the viruses transmitted by the whitefly B. tabaci. In Iran TYLCD was first detected in tomato fields from two provinces (Hormozgan and Sistan-Baluchestan) in the south, in 1990. Thereafter, during one decade, the disease was reported from many other provinces such as Kerman, Khuzestan, Bushehr, Markazi, Isfahan, Tehran, Golestan, Mazandaran, Yazd and Khorasan-Razavi. TYLCD has now become a major agent of tomato yield reduction in the Iranian tomato fields.