VIRAL DISEASES CAUSING THE GREATEST ECONOMIC-LOSSES TO THE TOMATO CROP .2. THE TOMATO YELLOW LEAF CURL VIRUS - A REVIEW

Tomato yellow leaf curl geminivirus (TYLCV), transmitted by the whitef ly Bemisia tabaci (Gennadius) is one of the most devastating diseases of cultivated tomato (Lycopersicon esculentum Mill.). TYLCV causes eco nomic losses up to 100% in tomato crop in many tropical and subtropica l regions, and is spreading towards new areas. The increasing economic importance of TYLCV has resulted in the need for accurate detection a nd identification procedures, stimulating intensive research efforts f ocused on virus biology, diversity, and epidemiology to develop succes sful control strategies. Breeding for resistance appears to be the bes t approach to control this disease, but to date only partially resista nt hybrids are commercially available. Search for new sources of disea se resistance needs to be intensified. The purpose of this paper is to collect and summarize all these efforts, offering an updated review o f these new approaches on virus transmission, molecular biology, varia bility, diagnostic methods, and potential ways to control. This will l ead to a better understanding of the virus-vector-host relationships, key factors in the adoption of disease control measures.