If one Big Island coffee grower is correct, the solution to the industry’s recent problem with the destructive coffee borer beetle might exist in the coffee plants’ own ecosystem.
The beetle was first detected on Big Island coffee farms this year, particularly in the dry South Kona area. Its spread has proved disastrous in some areas, costing farms as much as 75 percent of their usual yield.
Melanie Bondera of Kanalani Ohana Farm thinks the beetle is likely not new to the island and that the infestation might have been due to severe drought conditions that killed off a fungus — Beauvaria bassiana — that had been keeping the beetle in check for years.
Bondera said she got the idea from another farmer at a meeting last month and conducted a study of infected plants on the organic farm that she operates with her husband.
Examining scores of infested beans, Bondera found evidence of “white crystalline stuff” overflowing from beetle exit holes. When she cut the beans open, she found dead beetles stuck in the exit with the fungus growing out of their bodies.
Bondera, who holds a master’s degree in agriculture, speculates that the beetle has been in Hawaii for years but has been controlled by the presence of the fungus, which lives within the tissue of the coffee plant. She and other farmers think that when the drought hit, the fungus died off, allowing the beetles to do more damage.
