Thursday | December 14, 2017
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New coffee pest may be slow-spreading

The good news for Hawaii coffee farmers, if there is any to be found in the recent revelation that a new virus has been found in a Kona coffee farm, is that the virus may be slow-spreading.

That’s according to Scot Nelson, whose smartphone application, Plant Doctor, was used to help identify the pest, a previously unseen strain of emaravirus. The genus emaravirus is also a relatively recent discovery, Nelson said Friday.

“The positive thing is, the farmer indicated they had seen symptoms about six years,” Nelson said, referring to the Captain Cook farmer who sent him the first pictures of affected leaves.

The symptoms were limited to just a few trees and hadn’t spread in six years, Nelson said. That’s good news, because it means the disease doesn’t spread easily.

Nelson and other scientists found a type of mites on the leaves that are known to be carriers of other types of emaraviruses. Those mites don’t fly and only spread by wind, he added.

The bad news is, unlike fungal infestations, which can be treated, trees infected by viruses may have to be destroyed to kill the virus, Nelson said.

He’s hoping more farmers who have found the light spots on coffee tree leaves, as well as coffee cherry shriveled up like raisins, contact him or the Department of Agriculture, so officials can better study the virus.

Only when he and the department have collected more information and samples, and possibly only if they can introduce the virus to a healthy tree and see the same symptoms present themselves will he be able to definitively say the virus is causing the leaf spots and cherry damage.

The farmer didn’t even wonder about a possible pest on his tree until this year, when the trees weren’t harvested. He took a closer look and saw the shriveled coffee cherries, which appeared to render the coffee beans unusable, Nelson said.

Nelson and Agriculture Department officials will be in Kona next week to visit the farm where Nelson collected his first samples earlier this year. He said he’s hoping to be able to visit some additional farms, including one neighboring the first farm where similarly spotted leaves were seen but not yet reported.

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