Quarantine restrictions on Oahu-grown coffee have been expanded islandwide, limiting transport and shipping in an effort to prevent the spread of a coffee berry borer infestation.

The Hawaii Board of Agriculture expanded restrictions that had previously included only coffee grown at Dole Foods’ Waia­lua Estate Coffee Farms and roasted at the Old Waia­lua Sugar Mill. The expanded quarantine took effect Wednesday as a result of infestations at two more sites: a private Wahiawa residence in December, and the nearby University of Hawaii Poa­moho Research Station earlier this year.

Under the quarantine, a permit is required to transport unroasted beans, coffee plants and plant parts, used coffee bags and harvesting equipment from infested islands to uninfested islands. It also requires treatments and state inspections prior to shipping.

The same restrictions have been in place since 2010 on Hawaii island, where the coffee beetle borer made its first appearance in the state.

The Department of Agriculture says the pest is difficult to eradicate from Oahu and Hawaii island because the beetle, known to devastate crops in Central and South America, bores into and lays eggs inside of the coffee bean. The larvae feed on the bean, reducing the yield and quality, agriculture officials said.

The best defense is chemical treatments and cultural control methods to reduce the beetle’s population, the department said. Big Island coffee growers manage the pest by using an organic pesticide and field sanitation practices.