Hawaii farmers battling a devastating parasite might not get much relief from proposed legislation that would formally declare coffee leaf rust an invasive fungal disease.
State Senate Bill 744 would require the Hawaii Invasive Species Council to declare the fungus that causes coffee leaf rust — Hemileia vastatrix — as an invasive species in order to more easily secure funding for research and mitigation efforts.
Coffee leaf rust was only detected on the Big Island for the first time in 2020, but already poses a major threat to the island’s hundreds of coffee farms, said Mark Petersen, president of the Kona Coffee Farmers Association.
“It has been a very devastating problem for the whole industry,” Petersen said. “All of our farmers are trying to adapt their entire practises just to survive … and it’s not just the Big Island, it’s on every island.”
The disease spreads extremely easily, Petersen said. Spores of the fungus are carried by the wind and rain and attach to the leaves of coffee trees, which develop lesions, become incapable of photosynthesis, and then die. If left unchecked, he said, all the leaves will die, with the tree following soon after.
“Every time it rains, I go out and I see more spores on the leaves, and I have to deal with that,” Petersen said.
Petersen estimated that the Big Island’s coffee production in 2022 decreased by nearly 50% because of the disease.
The bill specifically compares the disease to another invasive fungus — rapid ‘o‘hia death, which the measure states has been “effectively mitigated” thanks to a coordinated effort by the Hawaii Invasive Species Council, the University of Hawaii, and hundreds of volunteers statewide.
However, Franny Brewer, program manager for the Big Island Invasive Species Committee, noted that officially designating any species as invasive might not mean much in Hawaii.
“I know the Hawaii Invasive Species Council was given the authority to classify invasive species in its administrative rules, but I don’t think it ever did that,” Brewer said. “There is no comprehensive list like that.”
The state Department of Land and Natural Resources evidently agrees.
In testimony submitted about the measure in February, DLNR Chair Dawn Chang wrote that while the department recognizes coffee leaf rust as a major agricultural threat, the Hawaii Invasive Species Council does not maintain a list of invasive species.
On the other hand, both Chang and Board of Agriculture Chair Sharon Hurd agreed that further funding is necessary to curb the spread of the disease. Hurd recommended an appropriation of $200,000 to the Department of Agriculture.
In the meantime, Petersen said farmers will need to be constantly diligent to mitigate their coffee losses. He said that the most critical practices to prevent the spread of the disease is to maintain soil health in order to bolster the trees’ immune systems, and to prune trees so they don’t trap wind- or rain-borne spores.
But, Petersen added, farmers might also have to make very hard decisions in the future. Because Hawaii is the last coffee-growing environment on Earth to be exposed to the disease, there already is some research into coffee varieties that are resistant to the fungus.
“But if we do that, then it’s not going to be Kona coffee anymore,” Petersen said.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.