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Hawaii NCPN

Citrus screenhouse at Hawaii, NCPN


Lab diagnostics

Commercial citrus production in Hawaii started the early 1800’s when island-grown fruits were exported throughout the Pacific Rim. The introduction of several citrus pests and diseases, however, has eliminated exportation due to quarantines and has relegated citrus to its current status as a minor agricultural commodity. Currently, only a few hundred acres are devoted to commercial citrus production, representing approximately 3-5% of the citrus sold in Hawaii. Most of these farms are small, family operations with less than five acres dedicated to citrus.


Dooryard citrus trees, however, are very common in Hawaii and may exceed the number of commercial trees. Hawaii does not have a program to distribute clean propagative materials to growers. Some nurseries import certified budwood from states with programs in place such as California. Due to the high incidence (~75%) of Citrus tristeza virus in Hawaii, other nurseries have identified trees with mild strains of the virus and use budwood from these trees to cross-protect against the more severe strains. The recent discovery of the Asian citrus psyllid (Diaphorina citri) in Hawaii has been cause for concern that Huanglongbing (HLB) is also present.


To date, no samples from Hawaii have tested positive for any of the three Candidatus Liberibacter species known to be responsible for this disease. Attempts are being made to establish an in-state program for the detection of these bacteria. The establishment of such a program may allow detection of other graft-transmissible pathogens of citrus to be added in the future.

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