01104naa a2200121 a 450000100080000000500110000800800410001910000150006024500890007526000090016452007310017377300780090416483751999-11-08       1991    bl ---       0--  u    #d1 aYEH, S. D.  aControl of Papaya ringspot virus by cross protectionbconventional versus innovative  c1991  aPapaya ringspot virus (PRV) is a major limiting factor for papaya production throughout tropics and subtropics. The unavailability of PRV-resistant papaya varieties, the difficulty of eradication, and the restricted host range of PRV make cross protection an attractive method of controlling this virus. Two mild virus mutants. PRV HA 5-1 and 6-1, that produce no conspicuous symptoms on papaya were obtained from nitrous acid induction. The mutants provide a high degree of cross protection under greenhouse conditions. Results of small-plot and large-scale field tests indicate that these are hihgly valuable strains. The application of cross protection for control of PRV has become a routine practice in Taiwan since 1984.  tProceedings of the international workshop tari, taichung, p.125-134, 1991