Passionfruit (Passiflora edulis and P. edulis f. flavicarpa) is a popular fruit crop grown in Taiwan as well as other tropical and subtropical countries. In 1983, a severe virus epidemic outbreak occurred on passionfruit in Taiwan and quickly destroyed our passionfruit juice industry within a year. Cucumber mosaic virus, Passionfruit woodiness virus and two other potyviruses were later detected to be the cause of the severe damage. Specific antisera against each passionfruit viruses were prepared and successfully applied in the routine indexing program for the production of virusfree planting materials. Using the serological techniques, the ecology of virus transmission in the fields was also revealed. Based on the virus transmission ecology information, a control strategy was thus developed in 1988 and tested in Pu-Li area in a consecutive two-year field experiments. It was found that by the use of virusfree planting materials, virus disease epidemic could be significantly suppressed and both the fruit yield and quality of passionfruit could be increased. Since 1989, eradication of all passionfruit trees in December and replanting with virus-free plantlets in the following January has become a routine control program in all plantation areas in Taiwan. By an estimate, virus disease incidence has been suppressed to a level lower than 20% each year after this control strategy being officially implemented since 1990. This paper describes the scientific efforts devoted to the studies on passionfruit virus diseases and their control in Taiwan. Also, we have listed the reported viruses that have affected various Passiflora species including passionfruit plants in Taiwan and other parts of the world. Passionfruit (Passiflora edulis and P. edulis f. flavicarpa) is a popular fruit crop grown in Taiwan as well as other tropical and subtropical countries. In 1983, a severe virus epidemic outbreak occurred on passionfruit in Taiwan and quickly destroyed our passionfruit juice industry within a year. Cucumber mosaic virus, Passionfruit woodiness virus and two other potyviruses were later detected to be the cause of the severe damage. Specific antisera against each passionfruit viruses were prepared and successfully applied in the routine indexing program for the production of virusfree planting materials. Using the serological techniques, the ecology of virus transmission in the fields was also revealed. Based on the virus transmission ecology information, a control strategy was thus developed in 1988 and tested in Pu-Li area in a consecutive two-year field experiments. It was found that by the use of virusfree planting materials, virus disease epidemic could be significantly suppressed and both the fruit yield and quality of passionfruit could be increased. Since 1989, eradication of all passionfruit trees in December and replanting with virus-free plantlets in the following January has become a routine control program in all plantation areas in Taiwan. By an estimate, virus disease incidence has been suppressed to a level lower than 20% each year after this control strategy being officially implemented since 1990. This paper describes the scientific efforts devoted to the studies on passionfruit virus diseases and their control in Taiwan. Also, we have listed the reported viruses that have affected various Passiflora species including passionfruit plants in Taiwan and other parts of the world.