HILO — In just over a year’s time, the varroa mite, a parasite that kills honeybees, has spread from the Hilo Bay area north to Onomea and south to Pahala, researchers say.
And it is not a matter of if, but when, the mites will spread to West Hawaii, said Ethel Villalobos, an entomologist at the University of Hawaii’s College of Tropical Agriculture and Human Resources.
Although it isn’t known how quickly it will happen, Villalobos said it will because bees are naturally on the move seeking sources of pollen, and farmers and beekeepers often move hives, and can unknowingly move a colony infested with parasite.
"The bottom line is: Varroa mites have been all over the world and the mainland for the last 20 years, and it’s substantially changed the way agriculture is done on the mainland. It will substantially change the way we do agriculture here," said Richard Johnson, owner of Onomea Orchards and president of the Hawaii Tropical Fruit Growers.
"It’s not the end of agriculture," he said. "It wasn’t on the mainland. We’re going to have to learn to live with it, we’re not going to eliminate the varroa mite. … It’s going to become an art of living with varroa."
More than 100 people attended the varroa mite panel discussion, part of the 19th annual Hawaii International Tropical Fruit Conference held Saturday at the Hilton Waikoloa Village. The panel featured researchers from UH’s College of Tropical Agriculture and Human Resources varroa mite project.
Established on Oahu and discovered near Hilo just over a year ago, the mite attaches to the European honeybee, burrows beneath its skin and feeds on the bee. Eventually, the mites spread in the bees’ hives, living off their blood. Mites reproduce within single cells of bees and larvae.
The mites weaken the bees, allowing other viruses and diseases, such as deformed wing virus, to kill the bees off. Once a colony dies, bees from healthy colonies often take over the diseased hive, thus spreading the mites.
In Hilo, the prognosis appears to be grim for the 130 feral hives that have been documented, said Scott Nikaido, who provides research support for the project. Within a year, 90 percent of those feral hives could be gone, reducing the bees that pollinate local farmers’ crops, he said.
Should the mite spread islandwide, researchers say that between 75 percent and 90 percent of feral hives will be lost. For managed hives, researchers expect that 50 percent of those will succumb to the varroa mite.
"They may make a comeback, but the hive will never be the same again," Nikaido said, offering up an example — a Waianae winter melon farmer who saw a 50 percent decrease in the crop in 2008 because of a lack of bees in the area.
"There’s nowhere near enough bees for the whole Waianae area," Nikaido said. "Farmers are going to have to rely on bringing in bees just to get adequate pollination."
When it comes to combating the parasite, Villalobos said that chemicals are not as effective as finding an organic way to get rid of the mites because they seem to become resistant to chemicals — much the same way that viruses can become resistant to antibiotics.
Research is currently aimed at attempting to use a "drone comb removal trap" that sacrifices male bees, which allows the mites to infest the males, which are subsequently removed from the hive.
Also, researchers are testing whether thymic acid, which is naturally found in hives, and formic acid, which is naturally produced in plants, can kill the mites. Researchers are also testing bees with good hygienic behavior, which naturally "throw out" infected bees from the colony, as well as finding locally produced queens, Villalobos said.
In an attempt to slow the spread, researchers are offering educational workshops as well as passing out brochures, said Villalobos, noting that the project is currently tailoring its materials to the Big Island.