Rapid Ohia Death Detected for First Time on Oahu

A species of fungi which causes Rapid Ohia Death (ROD) was found on a dead ohia tree in the Koolau Mountains.

The first case of Rapid Ohia Death (ROD) has been found on the island of Oahu yesterday, according to the state Department of Land and Natural Resources. The disease was discovered on a dead ohia tree on private land in the Koolau Mountains above Pearl City. Researchers gathered a sample from the tree and analyzed it at the USDA Agriculture Research Service lab in Hilo. They found the presence of Ceratocystis huliohia, a fungal species with the ability to kill ohia trees.

The good news is that although the fungus is associated with ROD, it is less aggressive than Ceratocystis lukuohia, another fungi strain that has the ability to cause much greater harm to ohia trees through faster infections and spreading. The location of this infected ohia tree is also a small blessing, as it is extremely remote and it is unlikely that the fungi will be able to spread to the island’s greater population of ohia trees, which grow along the Koolau and Waianae mountain ranges. 

Of course, the severity of this issue can not be underplayed, and government organizations are using a combination of helicopters, drones and ground surveyors to determine if, and how much, the disease has spread. ROD has claimed thousands of ohia trees, which are rooted in Hawaiian culture, and has most significantly impacted Hawaii Island, where it has infected over 135,000 acres of ohia forests. 

Residents and visitors can help protect our ohia trees, and reduce the risk of infection, by following these guidelines provided by DLNR.

• Avoid injuring ohia. Open wounds on ohia are an entry point for disease spores. The disease can also spread from tree to tree on machetes or other tools.

• Don’t transport ohia inter-island.

• Don’t move ohia wood or vegetation, especially from areas known to have ROD.

• Clean your hiking boots/gear/tools. Scrub off all dirt and spray boot soles and tools with 70% rubbing alcohol, and wash your clothes in hot water and use a dryer to ensure the disease is not spread on boots and clothing.

• Wash your vehicle if driving near ohia forests. The disease can remain alive and infectious in soil, so wash all dirt off vehicles.

If you find dead or dying ohia trees on Oahu, contact the Oahu Invasive Species Committee at (808) 286-4616 or e-mail oisc@hawaii.edu.