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The Honolulu Advertiser
Posted on: Tuesday, March 16, 2004

Taro production hits record low

 •  Chart: Hawai'i taro production, 1946-2003

By Vicki Viotti
Advertiser Staff Writer

The production of taro is at an all-time low, and the state is struggling to combat threats to the industry from two pests: the apple snail and the disease known as taro pocket rot.

The apple snail, Pomacea canaliculata, arrived in Hawai'i in 1989 to be sold as escargot.

Advertiser library photo • August 1993

The low taro supply — which also resulted from storms and flooding in the past year — has not yet affected the stock of poi on supermarket shelves. That could change with the approach of summer, when graduation parties and other events drive up demand.

"Part of the problem was weather related," said Eric Enomoto, treasurer for poi processor HPC Foods Ltd. "We did have some cold, rainy weather conditions and flooding that did have an additional effect on the crop yield."

But among the persistent problems, experts rank the apple snail — Pomacea canaliculata — as a major culprit in the current crop decline. In the past few years it has become a problem in previously uninfested Hanalei, the heart of taro cultivation in Hawai'i. The island of Kaua'i produces more than half of the state's taro crop.

Farmer Ernest Haraguchi, whose Hanalei farm is the state's largest, was not surprised to hear about a state report that crop yields for 2003 had dropped 18 percent from the previous year.

"I predicted that it was at least 20 percent, so that sounds right," Haraguchi said.

The report, issued by the Hawai'i Agricultural Statistics Service, put last year's taro production at 5 million pounds; the previous low, reached in 1997, was 5.5 million pounds. Urbanization has driven down harvests from a high of 14.1 million pounds in 1948; more recently the decline has resulted from pests and diseases, according to the report. Median production in the past decade has been about 6.1 million pounds.

Levi Maon, a buyer for the Daiei store chain, said availability has kept up with the poi demand, although the supply of other related items — laulau and taro leaves, for example — is not abundant. And Charin Tomomitsu, HPC sales and marketing director, said that so far the taro used in production has been of acceptable size, not the stunted, storm-damaged produce of a year ago.

"With the weather we've been having, it's hard to say whether later growth will be affected," she said.

The infestation of apple snails dates back almost 10 years and various tactics have been used to keep the pest in check — everything from releasing ducks into the fields to dine on the snails to powdering the crop with copper sulfate, a pesticide, for brief periods.

Both methods have had some success, said University of Hawai'i snail expert Robert Cowie, but it's limited: Prolonged use of chemical pesticides is barred in wetland areas such as taro fields because they can leach back into the environment, and the duck brigades can do some damage to the crop themselves.

Most recently, Haraguchi had been working with Harry Ako, a UH molecular bioscience researcher, on a pilot project to harvest the snails for sale as escargot in restaurants. The idea is more to avert taro crop losses than to make a profit from the snails themselves, Ako added.

But a year ago, the renewal of the project's federal grant was declined and Haraguchi has been in a holding pattern to keep the snails under control. The only way to do that is to devote half the time of one laborer to doing nothing but picking the snails, Ako said, who added that the infestations around the island have been curbed before but always recur.

"It looks like we shouldn't celebrate and get happy when we control it, that these are a constant problem and need constant pressure to keep them in check," he said.

Moreover, Cowie said snail harvesting to control the pests runs the risk of tempting non-farmers to start propagating snails, which can reproduce at an astronomical rate: Two snails can result in a population of millions after a year.

"My stand is, I think it's incorrect to promote a pest," he said. "Someone who doesn't have snails in their area will think they can grow them, saying, 'They're never going to escape from our facility,' but they will."

Baby snails are a millimeter in diameter and can travel easily, Cowie said — on birds, through wind, and hidden in the taro leaf sheaths that are then replanted in new fields.

Researchers are also weighing ways of controlling the plant rot that plagues crops throughout the state. UH plant pathologist Janice Uchida said the disease has been traced to a newly identified species from the genus Phytophthora, which can be controlled through pesticides.

But again the problem is that continual pesticide use is barred in fields where runoff into streams and the ocean is such a risk. So organic approaches — such as drying out the taro field and tilling in a cover crop that can compost and kill some of the microscopic pest — are being researched, she said.

Some progress is essential, said Haraguchi, if the taro farmer is to stay in business.

"If we don't keep this in check," he said, "I don't see how we can survive."

Reach Vicki Viotti at vviotti@honoluluadvertiser.com or 525-8053.

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Correction: The island of Kaua'i produces more than half of the state's taro crop, including the yield of Ernest Haraguchi's Hanalei farm, which is the largest in the state. A previous version of this story included incorrect information.