Erosion and disease take toll on tough coconut trees
I was wondering about the dying or dead coconut palm trees along the Windward coast. There are a whole bunch in the Hauula Beach Park area. Is there some disease or is it the weather?
Answer: A fungus known as coconut heart rot may be responsible for many dead or dying trees in Windward Oahu, but the ones at Hauula Beach Park are dead because they weren't getting enough water.
About six dead palms at the park will be removed within the next couple of months, said Dana Takahara-Dias, deputy director of the city Department of Parks and Recreation.
The problem was "an inadequate irrigation system," damaged by coastal beach erosion, she said.
The trees could have been watered manually, but with a roving maintenance crew also responsible for other parks, it just wasn't getting done enough, she acknowledged.
Replanting is not expected until the erosion's impact on the irrigation system is corrected, especially because it would cost about $2,500 for each new tree, Takahara-Dias said.
Meanwhile, two older coconut trees, "at the end of their useful life and just a hazard now," also will be removed from the park, she said. Hauula Beach Park is used as a campground, so safety is a concern.
Takahara-Dias said this is an isolated case and coconut trees at other city parks are not dying.
Meanwhile, there are all kinds of reasons why a tree may die, but coconut heart rot periodically ravages Hawaii's coconut palms, primarily in windward areas.
The disease is "episodic, it comes and it goes," said Jeri Ooka, a University of Hawaii associate plant pathologist based at the Kauai Agricultural Research Center. It thrives in wet conditions and usually appears after big storms.
On Kauai, there was a big kill-off of coconut trees after Hurricanes Iwa and Iniki, in 1982 and 1992, respectively, and after Hurricane Dot in 1959.
The bad news is that you probably won't see as many coconut trees in the windward areas as in the past. The good news is that coconut trees "are resilient plants and you can get a fruit-bearing tree in five years," Ooka said. Even a diseased tree can live for up to 15 years, he said.
How can you tell if a tree has the disease?
Initially, the fruit will show symptoms and start rotting. When the center leaf turns brown, that's a grim sign.
A coconut tree has only one growing point, in the middle of the tree, "so when that dies, the tree is effectively dead," Ooka said. A fringe of fronds will hang on for a while, but ultimately will drop off.
Ooka said there is no cure once a tree gets the rot, but there is a way -- injecting the diseased trees with potassium phosphite -- that will hold off the disease for a while.
However, Ooka said potassium phosphite hasn't been officially approved for use as an injectable spray, so he can't recommend it. It's approved for use as a fertilizer, but not as a pesticide, he said.
Hawaii Coconut Protectors on Maui offers an injectable product that is said to be effective in protecting a tree from the fungus. Information can be found at coconutprotectors.com or by calling (800) 417-7435.
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