In the summer of 2010, watermelon plants (Citrullus lanatus Thunb.) from eight fields surveyed in two districts (Jenin and Qalqilia) in the West Bank of the Palestinian Authority (PA) exhibited typical Watermelon chlorotic stunt virus (WmCSV) symptoms including yellow veining, chlorotic mottling, stunting of young leaves, and reduction of yield. Disease incidence ranged from 8 to 98% and was associated with whitefly (Bemisia tabaci) infestation. In symptomatic leaves of 79 of 215 watermelon plants examined, geminiviral DNA was detected by PCR (3) and rolling circle amplification (RCA) (2). Geminivirus DNA-A and DNA-B component fragments were amplified by PCR using degenerated and specific primers (3). The full-length DNA-A of WmCSV-[PAL] was amplified from field-collected watermelon plants using WAI-XbaI-(v)/WAI-XbaI-(c) primer pair, and the generated PCR product was sequenced (3). A DNA-A fragment (2,017 bp) (GenBank Accession No JN673223) comprising a conserved region of the coat protein (AV1), AC5, AC3...