Papaya strains of papaya ringspot virus (PRSV-P) causes a major disease problem on papaya cultivation in tropics and subtropics. PRSV-P is a member of potyviruses. The positive sense PRSV RNA is 10326 nucleotides in length and is translated into a polyprotein of 3344 amino acids. The cant protein regions of five sequenced PRSV strains shows mom than 89.6% nucleotide identities. The thermal inactivation point of PRSV-P is 50-60℃ within to minutes. Its dilution end point in at 10^(-3)-10^(-5) and with longevity of 8 to 72 hours. It shows leaf deformation and mottles on papaya, water soaked steaks on leaf petioles and stem, and water soaked ringspot on fruit. Strains of PBSV-P from Taiwan include SMN, SM, M, SMD and DF. PRSV-P can be transmitted mechanically and through aphids in a non-persistent manner. Papaya seeds do nut bear virus. Systemic hosts include Carica papaya L, and members of Cucurbitaceae. It causes local lesions on members of Chenopodiaceae.