University of Hawaii faculty have identified a new coffee pest. UH officials on Thursday said the disease symptoms have not been reported anywhere else in the world. The symptoms are circular yellow or yellow-green lesions, or spots, about one-quarter of an inch in diameter on the leaves and petioles. Anecdotal evidence suggests that it renders the coffee cherries unusable, though it is not yet known what the lesions look like on the cherries.
Pictures of affected leaves are available at sites.google.com/a/hawaii.edu/emaravirus-infects-coffee-in-Hawaii/.
In January, a farmer contacted Scot Nelson, via his plant diagnosis application, The Plant Doctor, to ask about the spots on his coffee leaves. Nelson had never seen the disease before, officials said. Another professor and an extension agent found several symptomatic plants in two locations at the farm, and they could also see some symptomatic plants across a fence at a neighboring coffee farm.
The second professor, Michael Melzer, analyzed the leaves and found a new species of virus similar to emaraviruses in the symptomatic coffee. There is no specific evidence that the virus causes this disease, though efforts are underway to investigate. To date, no emaraviruses have ever been reported to infect coffee. Emaraviruses are transmitted by eriophyid mites, which can be spread on wind currents as well as by the movement of infected plant material.
They are asking coffee farmers and community members to provide more information that might help identify the pest by checking coffee for symptoms and contacting Nelson at email@example.com or via his Plant Doctor app, which can be downloaded and used for free by iPhone and Android users, or Andrea Kawabata at firstname.lastname@example.org. The HDOA has expressed interest in conducting a survey of farms in the area to determine the spread of the disease, but this will take time, so individuals are encouraged to report on their own crops as soon as possible.