In a move to protect the state’s ohia trees, Gov. David Ige has approved a ban on the importation of plants, plant parts and seeds in the myrtle family, including some commonly used in floral arrangements.

The ban, which goes into effect Friday, is aimed at preventing the introduction of new strains of a fungus and other pests and diseases that threaten not only ohia trees but native forests and watersheds, as well as horticultural and agricultural industries.

The primary threat is a fungus, Puccinia (Austropuccinia) psidii, commonly known as ohia rust or guava rust, which infects plants in the Myrtaceae family, including a wide range of plants, such as guava, eucalyptus and ohia, officials said.

The new rule also prohibits the import of Myrtaceae plant parts that are commonly used in the floral, nursery, landscaping and food industries. They include wax flower, myrtle, bottle brush, allspice and clove.

Processed allspice and cloves are not affected by the rule, nor is the status of Myrtaceae plants already in the state.

The new rule bans the introduction of any Myrtaceae plant, plant part, or seed except:

>> Dried, nonliving plant materials;

>> Seeds, with no other plant fragments, that have been surface sterilized using an approved treatment;

>> Tissue-cultured plants grown in sterile media and in an enclosed sterile glass flask or similar container.

>> By approved permit.

If Myrtaceae plants, plant parts or seeds are shipped to Hawaii and do not fall within the four exceptions, the entire shipment may be delayed, quarantined, destroyed or returned at the expense of the owner or importer, officials said.

The full list of plants in the Myrtaceae family are listed at theplantlist.org/1.1/browse/A/Myrtaceae/.

The rule change previously was the subject of statewide public hearings and was approved by the state Board of Agriculture. Officials said notices were sent to shippers and importers in October letting them know of the pending rule change.

“The department realizes that this new rule has a considerable impact on some in the floral industry, and we have tried to give the industry as much lead time as possible to find alternatives to importing these particular plants,” Phyllis Shimabukuro-Geiser, state Board of Agriculture chairwoman, said in a news release. “We hope the industry will see an opportunity to grow and source flowers and foliage from within the state to help decrease the risk of importing other plant pests and pathogens.”