A new disease caused by the fungus Certocystis fimbriata is infecting and causing mass mortality of Metrosideros polymorpha (commonly called ohi’a), the most abundant native tree in Hawai’i. Additionally, the form and function of the treat make them the most important watershed tree on the island. Healthy trees appear to die within a few days to a few weeks of infection, which is how the disease got its name “Rapid Ohi’a Death” Already, hundreds of thousands of ohi’a have died across thousands of acres of land, including in the South Hilo, Puna, Ka’u, and Kona districts of Hawai’i Island.
C. fymbriata afffects the xylem systems circulating water through the trees. Current research points to wood-boring beetles as the fungus’ vector, allowing it to reach the xylem in the first place. The beetles burrow into trees to live and breed and then carry spores on their exoskeletons when they move to a new host. There is also research looking into wind dispersal of the fungal spores, which could be even more detrimental than the beetles.
It is unknown how C. fymbriata originally got to Hawai’i, although there are currently two separate species that have been isolated and identified. They are being described and renamed, because there are no exact matches anywhere else in the world.
There are several ways that local residents can help prevent the spread of the fungus. Don’t move ohi’a wood or ohi’a parts, because they could potentially be infected. Don’t ever transport ohi’a to another island, and follow the Hawai’i State Department of Agriculture quarantine rule. Clean tools used for cutting ohi’a with 70% rubbing alcohol, which will sterilize the tools and effectively kill off any fungi. Also use 70% rubbing alcohol on any shoes, after brushing off loose soil; and wash clothing with very hot water and soap. For vehicles, one can use a pressure washer and soap, making sure to get all soil off of the tires and undercarriage.
The Hawai’i Tribune-Herald reported recently that “after more than a year of emergency response efforts, collaborators working to stop the spread of rapid ohi’a death are shifting to a long-term research and management strategy”. There is a three-year plan presented that will address several objectives, including community outreach efforts and creating a “sustainable, coordinated, and efficient response” to new outbreaks. Efforts have already reached $2.3 million, with funding coming from federal, state, county, and private sources. The first year of strategic response will total over $3.6 million and the total three-year cost is estimated at $10 million. There are still specific response plans that need to be developed fr seed collection and forest restoration in already-affected areas. However, it remains to be seen if there will be a viable course of action to save ohi’a before rapid death decimates the island’s populations.
Original article at westhawaiitoday.com:
What is rapid ohi’a death?