Recent helicopter surveys led foresters with the Department of Land and Natural Resources (DLNR) to take samples from ten dead ‘ōhi‘a in two locations within the Līhu‘e-Kōloa Forest Reserve. Six trees tested positive for Ceratocystis lukuohia, an aggressive fungal pathogen causing Rapid ‘Ōhi‘a Death (ROD) across the state.
A total of 22 trees in three separate locations across Kaua‘i have now tested positive for the fungus.
“It is very important to do all we can not to accidentally spread the pathogen around on our vehicles, boots, and clothes,” said Sheri S. Mann, Kauai Branch Manager for the Division of Forestry and Wildlife (DOFAW).
Since the disease was identified on Hawai‘i Island in 2014, more than a million trees have died — with more than 90 percent of those testing positive for C. lukuohia. On Kaua‘i, the number of trees that have tested positive for C. lukuohia is much lower than on Hawai‘i Island.
The dead ‘ōhi‘a in upper Wailua is fairly accessible, so experts are asking for people’s help in containing the disease.
“These deadly microscopic fungal pathogens can be moved around the island in mud,” said Tiffani Keanini, project manager of the Kaua‘i Invasive Species Committee (KISC). “Theoretically, all it takes is one spore to infect an ‘ōhi‘a tree. So, we’re stressing bio-sanitation practices. Basically, leave mud where you found it. That may be easier said than done, but every little bit helps.”
Boot brushes have been installed at numerous trailheads around the island. While supplies last, KISC is also giving away bio-sanitation kits. Anyone interested in getting one should email email@example.com or call 808-821-1490. Each kit contains a boot brush, bottle of isopropyl rubbing alcohol, and educational literature.
Experts encourage these simple decontamination practices:
1) Avoid injuring ʻōhiʻa. Wounds serve as entry points for the fungus and increase the odds that the tree will become infected and die. Avoid pruning and contact with heavy equipment wherever possible. Avoid cutting new trails in ‘ōhi‘a forests and stepping on their roots.
2) Clean gear and tools, including shoes and clothes, before and after entering the forest and areas where ʻōhiʻa may be present. Brush all soil off tools and gear, then spray with 70% rubbing alcohol. Wash clothes with hot water and soap and, if possible, dry on the high heat setting in the dryer.
3) Wash your vehicle with a high-pressure hose or washer if you’ve been off-roading or have picked up mud from driving. Clean all soil off tires–including mountain bikes and motorcycles–and vehicle undercarriage, preferably with soap and water.
4) Don’t move ʻōhiʻa wood or ʻōhiʻa parts, including adjacent soil. The disease can be spread to new areas by moving plants, plant parts, and wood from infected areas to non-infected areas.
5) Keep your eyes open. If you see ʻōhiʻa with a limb or crown turning brown, take a picture and send it to KISC via email (firstname.lastname@example.org) or phone (808-821-1490) and describe exactly where you saw the tree. Samples of the wood must be taken by trained technicians and tested in a laboratory to confirm the presence of the ROD fungi.
‘Ōhi‘a is the most common tree in our native forest, and it’s absolutely vital to our forest ecosystem and watershed. To learn more about ROD, visit rapidohiadeath.org.