Leaf Curl Disease: A Significant Constraint in the Production of Tomato in India

Tomato ( Lycopersicon esculentum Mill. ) is one of the most economically important vegeta- ble crops in the world. Among the major biotic constraints, virus-associated Tomato leaf curl disease (ToLCD) is a major limiting factor affecting its cultivation and yield. Different symptoms associated with disease are reported such as leaf curling, puckering of leaves, vein yellowing, stunting, excessive branching, from pale yellowing to deep yellowing, and small leaves. The genus Begomovirus is a circular single-stranded DNA virus which is exclusively being transmitted by whitefly ( Bemisia tabaci ) in a persistent circulative man- ner. Most of the begomovirus species are monopartite (having DNA-A molecule only), except few species, which are bipartite (having DNA-A and DNA-B as the genomic component). No absolute effective control measures of the disease could be developed so far, except resistance, management of insect vectors, and altering the dates of sowing to avoid peaks of insect vector population. This chapter reports an account of history, symptoms, transmission, genome organization, distribution, and management of Tomato leaf curl disease.