S-77. Current studies on divergence and management of whitefly-transmitted geminiviruses in Indonesia

Whitefly-transmitted geminiviruses (Begomoviruses) have become major constraints to production in crops throughout the world. Begomoviruses cause serious disease problems in vegetable and fiber crops and are considered an important group of pathogens. Beginning in the early 2000’s, numerous epidemics of Begomoviruses occurred in chilli pepper crops throughout Indonesia, especially in Java. These epidemics resulted in complete crop losses in some cases and causing farmers ceased planting the crops. The primary reason for this increase in epidemics was the long and severe dry season that caused establishment of high population of whitefly, Bemisia tabaci, the vector of Begomoviruses. Other major crop plants impacted by Begomoviruses in Indonesia are tomato, tobacco, and cucumber. Biological and molecular characterization reveals that several Begomoviruses are associated with the disease. Based on sequence comparisons and phylogenetic analyses, it is known that Begomoviruses infecting chilli pepper in Indonesia is different from those infecting tomato, whereas tomato infecting geminiviruses was most closely related to ageratum yellow vein virus (AYVV). In addition to high genetic diversity of Begomoviruses in Indonesia, disease control is becoming very difficult due to characteristic of relationship between Begomoviruses and its insect vector. Breeding program for Begomovirus resistance varieties is one of major activities in regard to disease control strategy in Indonesia since commercial cultivars carrying resistance to the diseases have not yet been released. Application of low-to medium-input crop management has been evaluated for adequate control of vector and alternate host.