Frequently Asked Questions

Frequently Asked Questions about Biotech Papaya

• What's the story behind biotech papayas?
• How have biotech papayas benefitted growers and consumers?
• How does plant biotechnology work with papayas?
• Is there a more "natural" way to control the virus in papayas without using plant biotechnology?
• Where is papaya grown?
• Who developed this technology and who owns the rights to it?
• How many papaya farmers are in Hawaii and what is the average farm size?
• How about consumers in important export markets such as Japan?

What's the story behind biotech papayas?

Papaya is a succulent fruit grown in tropical and subtropical lands around the world, including Hawaii. It grows in bunches on fast-growing trees. The Papaya Ringspot Virus (PRSV) is the most widespread and destructive virus disease affecting papaya, capable of virtually wiping out the crop in a given area. Hawaii's papaya growers moved from Oahu to the "Big Island" of Hawaii in the 1950's to escape the virus. Unfortunately, the virus showed up there in 1992, and production dropped by more than 40 percent by 1998 with no end in sight. Fortunately, however, a team of scientists from the University of Hawaii, Cornell University, the U.S. Department of Agriculture and the Upjohn Company had been working on a genetically modified variety that was able to resist the ringspot virus. The new variety was approved by regulators, and seeds were made available to growers in May 1998. By 2001, the harvest had rebounded nearly to pre-infection levels. ¹

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How have biotech papayas benefitted growers and consumers?

There's little doubt the ringspot virus would have virtually wiped out the Hawaiian papaya growers had the biotech varieties not become available in the nick of time. As Hawaiian papaya grower Ken Kamiya put it: "For a while, we were able to contain its spread by destroying infected papaya trees. Yet this was a drastic remedy. One year, I had to cut down half my orchard. By the 1990s, however, it was almost pointless for Hawaiian farmers to raise papayas. The risk of crop failure was too high. I stopped growing the fruit and so did most of my neighbors."² The new biotech varieties put Kamiya back in business. Consumers, meanwhile, have benefitted from the continued availablity of succulent, highly nutritious fruit. Most of Hawaii's production is shipped to the U.S. mainland, Canada, or Japan.

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How does plant biotechnology work with papayas?

Researchers inserted a gene that made the plants resistant to the ringspot virus - similar to the way a vaccine makes people immune to disease.³ Researchers identified and cloned the gene that produces the coat protein in the virus, then inserted the gene into the papaya. The gene then makes the plant resistant to the ringspot virus, just as a flu shot makes people resistant to the flu. Research is also underway in other papaya growing regions to use biotechnology to combat papaya diseases.

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Is there a more "natural" way to control the virus in papayas without using plant biotechnology?

Ringspot virus is spread by tiny insects called aphids, so it is very hard to control. Measures can include:

• Quarantine;
• Use of virus-tolerant conventional varieties;
• Use of netting to keep out aphids;
• Heavy pruning of young plants to delay flowering and build plant strength;
• Heavy and frequent use of insecticide;
• Burning all infected plants and nearby ground plants and destroying all papayas within a large surrounding area once the virus appears

Unfortunately, these steps are expensive and difficult to maintain. Virus-tolerant varieties tend to lose their tolerance after a couple of years in the field, for example. Small-scale producers can't afford netting or the labor involved in pruning. Many growers find heavy use of insecticide to be undesirable. Finally, cutting down and burning infected trees is a drastic remedy that can put a farmer out of business.⁴ No wonder papaya growers in Hawaii have enthusiastically embraced genetically improved varieties, which permanently resist the virus and have saved their livelihoods.

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Where is papaya grown?

Papaya is native to southern Mexico and is intolerant of frost, so it is grown in tropical and subtropical regions around the world. The leading producers are India, Brazil, Nigeria, Indonesia and Mexico. The largest exporter to the United States is Mexico. ⁵

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Who developed this technology and who owns the rights to it?

The research culminated more than 20 years of work led by scientists from Cornell and the University of Hawaii, building on research done by private companies. Access to the technology is controlled by the Hawaii Papaya Industry Association and its Papaya Administrative Committee, which produces the seeds and makes them available to growers at cost.⁶

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How many papaya farmers are in Hawaii and what is the average farm size?

As of 2011, the industry in Hawaii consisted of 172 farms with a total of 2,000 acres, including 1,300 acres harvested, so the average farm has only eight acres from which papayas are harvested. ⁷

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What has happened in important export markets such as Japan?

Japan was a major export market for Hawaiian papayas until the genetically engineered varieties came to predominate. Japan allows the import of biotech products only after exhaustive review. Approval was granted beginning in 2012, and Hawaiian growers hope to rebuild their market there. Costco is now selling the genetically modified Hawaiian papayas in its stores in Japan. ⁸

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