Imagine Kaua’i and the rest of the state stripped bare of lush, palm-frond coconut trees – the most recognizable symbol of the Hawaiian Islands, of tropical beauty and aloha. It could happen if steps are not taken to halt the
Imagine Kaua’i and the rest of the state stripped bare of lush, palm-frond coconut trees – the most recognizable symbol of the Hawaiian Islands, of tropical beauty and aloha.
It could happen if steps are not taken to halt the spread of the coconut heart rot, a fungus that has killed trees at an alarming rate, particularly in areas with high rainfall, state agricultural officials say.
The blight has decimated up to 25 percent of the palm trees on Maui. Statewide, the fungus has hit between 10 and 15 percent of the trees.
At stake is the future of a tree synonymous with Hawai’i and has helped attract millions of visitors to its shores over the years.
There is no cure for the blight, but the University of Hawai’i Agricultural Experimental Station in Wailua has begun research to find ways to either control or stamp out the disease.
Hawai’i Coconut Protectors, a private company on Maui, has taken the lead in trying to contain the disease while the experiments go on. For a fee, the company injects a nutrient into a tree to shore up its immune system, acting like a shield that protects the tree from the fungus, according to owner Philippe Visintainer.
The process only works on healthy trees. Once a tree contracts the disease, death is a certainty.
The fungus, Phytophthora katsurae, apparently made its home in Hawai’i more than 30 years ago, when it was identified by University of Hawai’i officials on Kaua’i. The fungus later entrenched itself on Maui, O’ahu and Big Island.
The disease has reached epidemic proportions in the wetter parts of each island, and has now spread from the windward to leeward sides of the islands, Visintainer said.
How the fungus got to Hawai’i is unknown, but scientists believe it might have been spread by heavy windblown rain, birds and rodents.
The fungus is carried to a healthy palm tree and works it way down into the heart of the palm, producing a rot that gradually destroys a growing shoot and eventually kills the plant.
The work of the fungus is marked by the death of a young, center leaf that turns brown and falls over.
As the fungus moves over the tree, the other remaining fronds drop. In a few months, all the fronds eventually fall off, leaving a bare trunk.
“If you see the palm tree dying from the inside out, then most likely it is the disease,” Visintainer said. “If you see it from the outside in, it could be anything. It could be the water, lack of nutrients, damage to the roots.” The fungus almost has a will to live. If the infected tree is not removed, the disease finds another host tree and kills it.
Unchecked, it can wipe out a grove of palms that have taken a lifetime to grow. Palm trees have a life span of between 70 to 100 years.
The fungus will remain active until infected trees and nuts are either incinerated or are deeply buried. Oospores also are able to survive in the soil without the host plant.
Oospores also could latch onto tools, gloves and equipment that were used to dispose of infected plants. If the tools aren’t cleaned, the fungus could spread to healthy plants.
Why be concerned with the fungus? Because it could cost as much as $5,000 to plant a single 50-foot tree, a high expense for any property owner and even more expensive for a hotel developer that wants many trees planted, Visintainer said.
The Kaua’i Farm Bureau has been alerted to the spreading disease, and fliers also have been circulated to educate the public, he said.
But more palm trees will die on Kaua’i because there is no attempt yet to pull in the reins on the disease, Visintainer said.
The two largest remaining coconut groves remaining on Kaua’i could be threatened, according to Kaua’i Farm Bureau. One is located at the old Coco Palms Hotel, the island’s flagship hotel of the 1950s. The grove trees are old, and to replace those when they die, younger ones were planted along side the older ones.
The other grove is located on a parcel on the mountainside of Kuhio Highway in Waipouli.
More than 100 years go, the grove produced copra (coconut meat) for export.
The industry fade because it became cheaper to grow coconut elsewhere in the world.
Visintainer said he is working with Kaua’i Nursery & Landscaping, the largest landscaping company on the island, the Kaua’i Farm Bureau and the UH Agricultural Experimental Station to begin to look at ways to check the spread of the fungus.
Visintainer said his company has treated trees on Maui for the past year and has had an 80 percent success rate.
Trees at 10 hotels, including the Ritz Carlton, Maui Prince and the Embassy Vacation Resorts, condominiums, golf courses and private homes have been treated with positive results, he said.
“Maui is really doing well,” he said, adding his company hopes to start similar treatment programs on other islands.
In a test on Maui that involved 70 trees, 20 of the trees were injected with the nutrient, resulting in one casualty because the tree had already been infected, Visintainer said.
The other 50 trees were not treated, and 14 have died so far, Visintainer said.
The application of the nutrients will augment any methods that are found that will either check or kill the fungus, Visintainer said.
Research at the UH facility in Wailua in the early 1980s showed that protection from the fungus could be achieved by injecting a fungicide or fertilizer into the tree trunk.
But final results couldn’t be obtained because Hurricane Iniki in 1992 destroyed the experiment.
At this time, injecting any fungicide into a coconut tree as part of a treatment program is prohibited by the U.S. Environmental Protection Agency.
Staff writer Lester Chang can be reached at 245-3681 (ext.
225) and lchang@pulitzer.net
