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The Honolulu Advertiser

Posted on: Friday, August 27, 2004

Breakthrough reached in fight against fruit fly

By Beverly Creamer
Advertiser Education Writer

Researchers working among Hawai'i's small farmers have achieved dramatic success against a pest that has wreaked havoc here for more than three decades and cost the state's agriculture industry billions of dollars.

Agriculture experts call it a breakthrough in the fight against the fruit fly, which every year destroys as much as 50 percent of crop yield statewide in an industry that sees $536 million in wholesale sales alone and an additional $1.4 billion in secondary products such as juices, purees and canned fruits.

The implications are far-reaching. In Hawai'i alone, this new success raises hope that fruit and vegetable production can expand by as much as $45 million annually in the next few years, creating more agricultural self-sufficiency locally, better fruits and vegetables for consumers, and potentially new export crops to help the state economy.

Hawai'i has been at the center of research in the fight against the fruit fly, and successes in the Hawai'i Fruit Fly Area-Wide Pest Management suppression program are the result of several years of work on several fronts.

The team of federal, state and University of Hawai'i scientists that developed the plan has earned the U.S. Department of Agriculture's most prestigious honor, the 2004 Secretary's Honor Award for contributions to agriculture. UH entomologist Ronald Mau, who heads the UH team members, was singled out for particular mention.

The program has taken cutting-edge science developed at UH and applied it to about 200 small farms statewide, bringing tremendous reductions in losses to fruit and vegetable crops.

The fruit fly is a prodigious pest that reproduces in five days and lives in more than 400 different host plants.

At the 3,000-acre Aloun Farm in 'Ewa alone, crop losses from melon fly infestation dropped from 22 percent to 1 percent last year.

"Farmers have had reduced infestation, increased yield — they've had reduced pesticide use and an increased knowledge of fruit fly control," said project coordinator Roger Vargas, supervisory research entomologist with USDA's Agriculture Research Service.

"Farmers have a can-do attitude now. Previously they said 'I'm not going to plant pumpkin,' for instance. Now they're saying 'I think we can grow anything.' "

The $12 million project is a combined effort of USDA, the state Department of Agriculture and the UH College of Tropical Agriculture and Human Resources using the latest science and techniques to reduce infestation by four types of fruit flies that predominate in the Islands.

It has meant implementing new types of field sanitation, including immediate plowing under decaying fruit to destroy breeding areas, using improved lures and bait, and releasing sterile flies to mate with wild flies.

While the state considered trying to eradicate the flies in the late 1980s and early 1990s, that idea was eventually abandoned as too expensive. Farmers turned primarily to pesticides to control the bugs or gave up growing vulnerable crops.

The weapons

The multipronged suppression efforts used by the Hawai'i Fruit Fly Area-Wide Pest Management core team include:

• Monitoring what species are prevalent in an area to better target them by type.

• Good field sanitation, including immediate plowing under of rotting fruit, especially after harvest, to prevent fly breeding. Fruit fly reproduction cycles allow them to double in number within five days.

• Use of lures to target male flies and remove them.

• Use of poison bait immediately after flies emerge from the pupa stage. The poison is not applied to fruit, but on crops that grow tall. The flies naturally hover near taller crops and thereby ingest the poison.

• Use of sterile flies to mate with wild flies and reduce their numbers.

All of these techniques must be used continuously to keep suppression down, said UH researcher Raju Pandey. Any easing will allow the flies to proliferate again.

But during the past few years, with UH scientists working on everything from sterile fruit flies to better bait lures, Hawai'i has exported its technology around the world. Sterile flies produced in Hawai'i are used in California fields to kill occasional outbreaks; areas such as Guam and Taiwan are suppressing fruit flies using techniques created at UH.

Joe Liu, pesticide manager at Aloun Farms, has high praise for the work done here. He said the farm's pesticide use has dropped 60 percent since Aloun began working with the Hawai'i Fruit-Fly Area-Wide Pest Management core team. And there are no longer complaints from stores about quality.

"The program has been working very good," Liu said. "Before, we used to have complaints if they see a worm in our melon. The worst is when they send it back to you or won't take it. Now we don't have that complaint anymore and the quality is better."

The good thing about this is they supply the same amount of fruit to the market, but instead of planting 15 acres, maybe they need to plant only 12 acres, said UH researcher Raju Pandey.

"They can make the same amount of money for less work," Pandey said. "They save in water, fertilizer, labor, and get the same amount of fruit. And they don't have to use those nasty chemicals."

With this new success, the idea of complete eradication is being tentatively raised again.

USDA and UH "researchers are feeling more and more optimistic that this is something they may pull off," said Lyle Wong, administrator of the Plant Industry Division of the state Department of Agriculture.

That would require a major commitment of resources.

But there's new hope, and an eradication attempt will soon be tested on 800 acres in Puna on the Big Island, said Pandey.

Stuart Nakamoto, an economist with the UH College of Tropical Agriculture and Human Resources, said the strength of this suppression program could well open the door to Hawai'i farmers' growing everything from peaches and nectarines to apples, and other types of exotic melons — crops that could build the state's self-sufficiency and bring in another $45 million annually for its farmers.

"We can grow these now — but whatever comes out, the fruit flies just wipe out," Nakamoto said. "But with suppression, we might become commercial again, and then you can replace the imports. And then, what about exporting? That's a whole new ballgame."

Reach Beverly Creamer at bcreamer@honoluluadvertiser.com or 525-8013.