Smartphone App to Diagnose Virus in Papayas on Oahu

University of Hawaii scientists have developed an app for smartphones that allows the public to help them track what they believe is a decline in papaya ringspot virus, possibly resulting from increased plantings of papaya plants genetically engineered to resist the virus.

The app for both IOS and Android users allows researchers with the College of Tropical Agriculture and Human Resources to remotely identify whether backyard papaya plants are infected with the disease and to pinpoint their location.

The program also allows the public to mail in a sample of a papaya leaf to determine whether it’s of the genetically engineered (GE) variety.

However, for the most part, the service is limited to just the Honolulu metropolitan area.

Officials with CTAHR’s Department of Plant and Environmental Protection Sciences say the program currently lacks the resources to cover a greater area.

Richard Manshardt, a horticulturalist with the college’s Tropical Plant and Soil Sciences, told Big Island Now the pilot program is designed to test a theory that wider use of the GE papaya on Oahu has reduced the percentage of non-GE papaya plants there infected with the virus.

The ringspot virus, which was first found on Oahu in the 1940s, devastated that island’s papaya industry in the 1960s, and did the same thing to Big Island papaya harvests in the early 1990s. That led to the development of the Rainbow and SunUp ringspot-resistant papaya varieties, which scientists say now make up more than three-quarters of the papayas grown in Hawaii.

Brian Bush, of the UH Cooperative Extension Service in Hilo, said it’s believed that increased plantings of GE papayas have also reduced the impact of the virus on the Big Island.

The app, available at the Pic-a-Papaya website, guides users in taking photos of the papaya plant which are then sent to the researchers. The smartphone’s GPS capabilities allow them to pinpoint the location of the plant and map the extent of the virus.

While the GE specimens mailed in won’t be mapped, researchers hope the combined information will give them a better idea of how prevalent the virus has become.

Oahu participants who wish to replace either diseased or GE plants will be sent a small sample of either non-genetically engineered papaya seeds with a partial virus tolerance or the Rainbow or SunUp varieties.

Although the program is aimed at Honolulu, the researchers said they would also accept photo submissions from other areas, including the neighbor islands, and do their best to diagnose whether the subject plant contains the virus.

In addition to a wide variety of testing for plant diseases and pests and other analyses, the university’s Agricultural Diagnostic Service Center also provides testing on the Big Island to determine whether a papaya plant is of the GE variety.

The testing for GE papayas costs $3 each, and specimens – either seeds or young leaf material – can be dropped off at extension service offices in Hilo, Kamuela or Kainaliu. Locations and contact information for the offices is available here.