Epidemiology of Tomato Yellow Leaf Curl Virus in the Northern Regions of the West Bank, Palestine

Abstract

A survey was carried out in 2011 to study the epidemiology of tomato yellow leaf curl virus (TYLCV) in tomato growing sites of the Tobas and the Jenin districts. The survey studied the population of the virus-inoculative whiteflies and the possible virus reservoirs throughout the year. The maximum TYLCV-inoculative whitefly population was recorded in Tobas, compared with the Jenin district in the different growing seasons of tomato. In the Tobas district, the inoculative whiteflies started to appear in March and reached the maximum value of 7% in July and August. In the Jenin district, the maximum inoculative whitefly population of 6% was recorded in August. Such whiteflies started to appear in May, which is two months after their appearance in the Tobas district. Furthermore, populations of inoculative whiteflies occurred when farmers started their tomato growing seasons. The appearance of inoculative whiteflies coincided with availability of the virus natural reservoirs which harbor the virus and support the vector during the crop-free period. Infected cheese weed mallows (up to 12%) and tobacco plants (up to 7%) were the virus sources for whiteflies throughout the year in the Tobas and the Jenin districts respectively. Infected volunteer tomatoes (up to 93%) play a secondary role in the virus epidemiology as they disappear during winter (crop-free period) in both districts.