United States Department of Agriculture

Animal and Plant Health Inspection Service

Plant Protection and Quarantine

Risk Management Document

Importation of Unshu Orange Fruit, Citrus reticulata

Blanco var. unshu Swingle, from Korea into the 

Continental United States 

December 28, 2009

Plant Health Programs (PHP)

Regulations Permits and manuals (RPM)

Contact Person: Meredith C. Jones
Risk Management Document: Unshu orange fruit (Citrus reticulata var. unshu) from Republic of Korea

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Introduction

A Pest Risk Assessment (PRA) was developed by United States Department of 

Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS), Plant 

Epidemiology and Risk Analysis laboratory (PERAL) in response to the request from the 

Korean national plant protection organization (NPPO) to allow the importation of Unshu 

orange from Cheju Island of the Republic of Korea into the United States.

The PRA document, “Importation of Unshu Orange Fruit, Citrus reticulata Blanco var. 

unshu Swingle, from Korea into the Continental United States (USDA, 2009a), identified 

two pests, Xanthomonas citri subsp. citri (ex Hasse 1915) Gabriel et al. 1989 (ex Hasse 

1915) Gabriel et al. 1989 and Elsinoë australis Bitanc. & Jenkins 1936, of quarantine 

significance associated with Unshu orange fruit.

Citrus canker (Xanthomonas citri subsp. citri) and sweet orange scab (Elsinoë australis)

were rated as medium Pest Risk Potential in the PRA (USDA, 2009a), and according to 

the APHIS Guidelines for Pathway-Initiated Pest Risk Assessments Version 5.02

(APHIS, 2000), pests receiving a rating within the medium range may require specific 

phytosanitary measures in addition to standard port of entry inspection. 

History

APHIS developed a PRA titled ‘‘An Updated Evaluation of Citrus Fruit (Citrus spp.) as a 

Pathway for the Introduction of Citrus Canker Disease (Xanthomonas citri subsp. citri)’’ 

in March 2009 (USDA, 2009b). This PRA examines the information presented in 

Gottwald et al. (2009) and Shiotani et al. (2009) in the context of an earlier PRA. Based 

on the evidence presented in both the November 2007 PRA (USDA, 2007) and the two 

new publications, the updated PRA concludes that asymptomatic fruit (treated or 

untreated) is not epidemiologically significant as a pathway for introducing citrus canker. 

It further concludes that symptomatic fruit subjected to a packinghouse process that 

includes washing with disinfectants is also not epidemiologically significant as a pathway 

for introducing citrus canker. These conclusions led APHIS to prepare a supplemental 

Risk Management Analysis (RMA), titled ‘‘Movement of Commercially Packed Citrus 

Fruit from Citrus Canker Disease Quarantine Area; Supplemental Risk Management 

Analysis’’ (USDA, 2009c). The supplemental RMA takes into account the conclusions of 

the updated PRA as well as the evidence and discussion presented in the November 2007 

RMA.

In the supplemental RMA, APHIS determined that currently available scientific evidence 

provides additional certainty that commercially packed and disinfected fresh citrus fruit is 

not an epidemiologically significant pathway for the spread of Xanthomonas citri subsp. 

citri. As a result of this research, APHIS amended its domestic citrus canker regulations

on October 22, 2009. Each lot of harvested domestic citrus fruit from canker quarantine 

areas can be shipped to all U.S. States provided it is treated with an approved disinfectant 

and packed in a commercial packinghouse that operates under a compliance agreement. 
Risk Management Document: Unshu orange fruit (Citrus reticulata var. unshu) from Republic of Korea

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Equivalent phytosanitary measures, treatment with an APHIS-approved disinfectant and

packing in a commercial packing house, are therefore necessary for commercial 

consignments of Unshu oranges from Cheju Island of the Republic of Korea.

Recently, the Elsinoë australis pathotype natsudaidai was characterized from Citrus 

natsudaidai Hayata (Hyn et al., 2009); research needs to be performed to confirm 

susceptibility of different species of citrus (Hyn et al., 2009). We consider this pathotype 

a quarantine pest, however, at this time we have no evidence this pathotype attacks 

Unshu oranges (USDA, 2009a).

Risk Management Measures for Xanthomonas citri subsp. citri and Elsinoë australis

Unshu oranges produced in Cheju Island of the Republic of Korea may be imported if all 

of the following conditions are met: 

* Unshu orange fruits may be imported in commercial consignments only.

* Unshu orange fruits must be packed in a commercial packinghouse that is approved by 

and registered with the Korean NPPO. 

* Unshu orange fruits must be treated with a disinfectant in accordance with 7 CFR part 

305, and the consignment must have a Phytosanitary Certificate (PC) with an Additional 

Declaration (AD) issued by the Korean NPPO stating that the oranges were treated in 

accordance with 7 CFR part 305, inspected and found free of sweet orange scab.

* The regulated fruit is free of leaves, twigs, and other plant parts, except for stems that 

are less than 1 inch long and attached to the fruit. 

Summary

APHIS believes that the risk management measures discussed in this document will 

provide an appropriate level of phytosanitary protection against the pests of quarantine 

concern associated with Unshu orange fruit from Republic of Korea into the Continental 

United States.

Two pests of quarantine concern, the bacterium Xanthomonas citri subsp. citri and the 

fungus Elsinoë australis could reasonably be expected to follow the pathway on Unshu 

orange fruit. 

APHIS requires fruit moved from an area where citrus canker exists to be treated 

with an approved disinfectant and to be packed in approved commercial

packinghouse. The product may be imported in commercial consignments only 

after treatment with a disinfectant, only if it is free of leaves, twigs, and other 
Risk Management Document: Unshu orange fruit (Citrus reticulata var. unshu) from Republic of Korea

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plant parts, except for stems that are less than 1 inch long and attached to the fruit, 

and it must be inspected and found free of sweet orange scab.

The phytosanitary certificate with the additional declaration will require the Korean 

NPPO to inspect the fruit for symptoms of sweet orange scab. This disease can be 

detected if present, and if the symptoms are not present the fruit are unlikely to be a 

pathway for the disease (USDA, 2009a).

Author

José R. Hernández Ph.D.

References

APHIS, 2000. Guidelines for Pathway-Initiated Pest Risk Assessments. Version 5.02. 

Plant Protection and Quarantine, Riverdale, Maryland.

Gottwald, T., Graham, J., Bock, C., Bonn, G., Civerolo, E., Irey, M., Leite, R., López, M. 

M., McCollum, G., Parker, P., Ramallo, J., Riley, T., Schubert, T., Stein, B., and 

Taylor, E. (2009). The epidemiological significance of post packinghouse survival 

of Xanthomonas citri subsp. citri for dissemination of Asiatic citrus canker via 

infected fruit. Crop Protection 28:508-524.

Hyun, J.W., S.H. Yi, S.J. MacKenzie, L.W. Timmer, K.S. Kim, S.K. Kang, H.M. Kwon, 

and H.C. Lim. 2009. Pathotypes and genetic relationship of worldwide collections 

of Elsinoë spp. causing scab diseases of citrus. Phytopathology 99.:721-728.

Shiotani, H., Uematsu, H., Tsukamoto, T., Shimizu, Y., Ueda, K., Mizuno, A. & Sato, S. 

(2009). Survival and dispersal of Xanthomonas citri pv. citri from infected Satsuma 

mandarin fruit. Crop Protection 28:19-23.

USDA. 2007. Movement of Commercially Packed Citrus Fruit from Citrus Canker 

Disease Quarantine Area. Revised Risk Management Analysis. United States 

Department of Agriculture, Animal and Plant Health Inspection Service, Plant

Protection and Quarantine, Center for Plant Health Science and Technology, Plant 

Epidemiology and Risk Analysis laboratory. 123 pp.

USDA, 2009a. Importation of Unshu Orange Fruit, Citrus reticulata Blanco var. unshu 

Swingle, from Korea into the Continental United States. A Qualitative, PathwayInitiated Risk Analysis. Rev. 003. United States Department of Agriculture, Animal 

and Plant Health Inspection Service, Plant Protection and Quarantine, Center for 

Plant Health Science and Technology, Plant Epidemiology and Risk Analysis 

laboratory. 56 pp.
Risk Management Document: Unshu orange fruit (Citrus reticulata var. unshu) from Republic of Korea

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USDA, 2009b. An Updated Evaluation of Citrus Fruit (Citrus spp.) as a Pathway for the 

Introduction of Citrus Canker Disease (Xanthomonas citri subsp. citri). United 

States Department of Agriculture, Animal and Plant Health Inspection Service, 

Plant Protection and Quarantine, Center for Plant Health Science and Technology, 

Plant Epidemiology and Risk Analysis laboratory. 11 pp.

USDA, 2009c. Movement of Commercially Packed Citrus Fruit from Citrus Canker 

Disease Quarantine Area, Supplemental Risk Management Analyses. United States 

Department of Agriculture, Animal and Plant Health Inspection Service, Plant

Protection and Quarantine, Center for Plant Health Science and Technology, Plant 

Epidemiology and Risk Analysis laboratory. 28 pp.