Disease-Resistant Papaya Saves Hawaiian Papaya Industry

St. Paul, Minn. (August 20, 2004)—A new papaya, genetically resistant to papaya ringspot virus (PRSV), has rescued the Hawaiian papaya industry and may have the potential to do the same in other papaya-growing regions of the world, say plant pathologists with The American Phytopathological Society (APS).

“In 1992, Hawaii’s papaya industry faced economic disaster when PRSV was discovered in the Puna District of the Hawaii Island where 95 percent of the state’s papaya was grown,” said Dennis Gonsalves, plant pathologist with the USDA's Agricultural Research Service at the U.S. Pacific Basin Agricultural Research Center, Hilo, HI. By 1995, PRSV was widespread in Puna and the industry was in a crisis situation. PRSV rapidly spreads when aphids (small insects) pick up the virus on their mouths while feeding on infected plants and continue to feed on healthy plants.

In the late 1980s, plant pathologists began to develop transgenic papayas resistant to PRSV and the disease-resistant papaya was commercially released in May 1998.

“Today, we are proud to say that the transgenic papaya has fulfilled the hope of the Hawaiian papaya industry to control PRSV and to restore the supply of papaya to nearly the level existing before PRSV entered Puna in 1992,” said Gonsalves. The resistance of the transgenic papaya allowed farmers to directly reclaim their farms without first clearing their land of all infected papaya trees. The percentage of Hawaii’s fresh papaya production produced in Puna has risen from a low of 65 percent in 1999 to 84 percent in 2002.

Since PRSV is a worldwide problem on papaya, other countries have showed interest in developing the technology for their use. “Due to its success, the transgenic papaya has often been referred to as the model for the use of biotechnology to help agriculture,” said Gonsalves.

More on this subject can be found in this month’s APS feature article at www.apsnet.org/publications/apsnetfeatures/Pages/PapayaHawaiianRainbow.aspx. The American Phytopathological Society (APS) is a nonprofit, professional scientific organization dedicated to the study and management of plant disease with 5,000 members worldwide.