Although most of the papayas grown in Hawaii have been genetically engineered to resist papaya ringspot virus, non-modified varieties still exist, mostly in home gardens.
A group of University of Hawaii researchers want to monitor the disease and the non-modified plants and have created a smartphone application to do just that.
Available for both iPhone and Android, the Pic-a-Papaya app lets users assess each tree as healthy or diseased, according to a news release. Users also use the phone's global positioning system coordinates to map the location.
Papaya ringspot virus used to be common in the islands, having first been confirmed in the 1940s. By the 1990s, the disease, which is deadly to papayas but harmless to humans, was causing more than 50 percent losses to growers on the Big Island.
Scientists from the University of Hawaii, Cornell University and the U.S. Department of Agriculture developed a genetically modified variety that could resist the virus.
The first variety, Rainbow, underwent rigorous governmental review and was released for commercial production in 1998.
By 2009, more than 75 percent of the papayas grown in Hawaii were Rainbow or the related SunUp, which also is genetically engineered.
Since the advent of the genetically modified varieties, the incidence of the virus has declined.