United States Department of Agriculture

Animal and Plant Health Inspection Service

Plant Protection and Quarantine

Importation of Oncidium spp. in growing media 

from Taiwan into the United States 

7 CFR 319.37

Risk Management Document

September 28, 2012

Plant Health Programs (PHP)

Regulations, Permits and Manuals (RPM)
1

Introduction

The Code of Federal Regulations (CFR), 7 CFR 319.37, currently allows the importation of 

Oncidium spp. plants from Taiwan into the United States, but their importation in growing media 

is not authorized in 7 CFR 319.37-8 (Plants in Growing Media). All plants in growing media 

imported into the United States must be approved by APHIS and must comply with the 

regulations in 7 CFR 319.37-8 (CFR, 2011). The National Plant Protection Organization (NPPO) 

of Taiwan, the Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ), has 

requested the Animal and Plant Health Inspection Service (APHIS) of the United States 

Department of Agriculture (USDA) to add Oncidium spp. from Taiwan to the approved plants in 

growing media in 7 CFR 319.37-8.

In response to the request by Taiwan, and as required in 7 CFR 319.37-8(g), APHIS conducted a 

pest risk assessment (PRA), entitled “Pest Risk Analysis for the Importation of Oncidium Orchid 

Plants, Oncidium spp., in Approved Growing Media from Taiwan into the United States” 

(USDA, 2012). In the PRA, 14 quarantine pests were identified that may follow the pathway on 

Oncidium plants in growing media from Taiwan (Table 1).

Table 1. Quarantine pests likely to follow the pathway on Oncidium spp. plants in growing 

media from Taiwan

Type Taxonomy Pest

Acari Arachnida: Tetranychidae Tetranychus kanzawai Kishida

Insecta Lepidoptera: Arctiidae Amsacta lactinea Cramer

Lepidoptera: Noctuidae Spodoptera litura (Fabricius)

Thysanoptera: Thripidae Scirtothrips dorsalis Hood

Thrips palmi Karny

Mollusca Stylomatophora: Achatinidae Lissachatina fulica (Bowdich)

Stylomatophora: Agriliomacidae Deroceras laeve (Muller)

Stylomatophora: Helicarionidae Parmarion martensi Simroth

Petalochlamys vesta (Pfeiffer)

Stylomatophora: Philomycidae Meghimatium bilineatus (Benson)

Meghimatium pictum Stoliczka

Stylomatophora: Veronicellidae Laevicaulis alte (Férussac)

Bacteria Gammaproteobacteria: 

Enterobacteriaceae

Pectobacterium cypripedii (Hori) Brenner et 

al.

Fungi Ascomycetes: Pleosporales Bipolaris zizaniae (Y. Nisik.) Shoemaker

Source: USDA (2012).
2

Bipolaris zizaniae and Pectobacterium cypripedii were assigned a Medium pest risk potential 

and the remaining pests were assigned a High pest risk potential. Specific phytosanitary

measures may be necessary for pests with Medium pest risk potentials, and are strongly 

recommended for pests with High pest risk potentials (USDA, 2000).

As described in this Risk Management Document, APHIS evaluated 14 pests and determined 

that the requirements in 7 CFR 319.37-8 will be effective in managing the risk associated with 

these pests. APHIS will subsequently propose to add Oncidium spp. from Taiwan to the 

approved plants in 7 CFR 319.37-8(e). Below please find a discussion of the risk management 

measures for Oncidium orchids in growing media from Taiwan.

Risk management measures

Oncidium orchids as plants in growing media imported into the United States from Taiwan must 

be established in APHIS-approved growing media and comply with the requirements in 7 CFR 

319.37-8, the written agreement between APHIS and BAPHIQ, and all other requirements in 7 

CFR 319.37.

Discussion of risk management measures

The requirements in 7 CFR 319.37-8 comprise a “systems approach” with a combination of 

measures aimed at reducing pest risk. The International Plant Protection Convention (IPPC) 

defines a “systems approach” as “The integration of different risk management measures, at least 

two of which act independently, and which cumulatively achieve the appropriate level of 

protection against regulated pests” (IPPC, 2010). Similarly, the Plant Protection Act of 2000 

(SEC. 401. 7 U.S.C. 7701) defines a “systems approach” as “...a defined set of phytosanitary

procedures, at least two of which have an independent effect in mitigating pest risk associated 

with the movement of commodities.” 

Systems approaches are employed by an importing country to achieve an appropriate level of 

phytosanitary protection as an alternative to the use of single measures when a single measure 

does not exist, or is not feasible or desirable. The combinations of measures comprising systems 

approaches provide overlapping or sequential safeguards rather than depending on single risk 

management methods, such as fumigation or inspection alone (FAO, 2002; Podleckis, 2007).

Entry of Phalaenopsis orchids as plants in growing media from Taiwan is authorized in 7 CFR 

319.37-8 and a written agreement between APHIS and BAPHIQ has been in place since 2004 
3

(USDA, 2004). If approved in 7 CFR 319.37-8, a similar written agreement will be required for 

the importation of Oncidium orchids as plants in growing media from Taiwan.

The systems approach described in 7 CFR 319.37-8 and the existing agreement for Phalaenopsis 

plants in growing media from Taiwan contains several overlapping measures to manage a wide 

range of pest risks including:

 Plants are grown in compliance with a written agreement between the grower and the 

plant protection service of Taiwan;

 Inspection of mother stock;

 Plants are established in an approved greenhouse;

 Greenhouses are constructed to prevent the entry of pests and pathogens; 

 Sanitary procedures adequate to exclude plant pests and diseases, including cleaning and 

disinfection of floors, benches and tools, and the application of control measures to 

protect against any injurious plant diseases, injurious insect pests, and other plant pests 

are employed;

 All vents are covered with screening with openings no larger than 0.6 mm;

 Entryways are equipped with automatic closing doors (double or airlock doors are 

recommended);

 The greenhouse is free of sand, soil, weeds, plant pests and debris;

 All plants are grown on raised benches (at least 46 cm above the floor) supported 

by legs;

 The growing media is unused and approved in accordance with existing APHIS 

policy on approved growing media (7 CFR 319.37-8 (e) (1));

 Plants are watered only with rainwater that has been boiled or pasteurized, with 

clean well water, or with potable water;

 Plants are stored and packaged only in areas free of sand, soil, earth, weeds and 

plant pests; and

 Plants are rooted and grown in an active state of foliar growth for at least four 

consecutive months immediately prior to export in a greenhouse unit used solely for U.S. 

export plants.

Please see 7 CFR 319.37-8 for details. Table 2 summarizes the relation of these risk 

management measures to the 14 quarantine pests in Table 1.

Conclusion

APHIS has evaluated the 14 quarantine pests that may follow the pathway on Oncidium in 

growing media from Taiwan and has determined that the requirements in 7 CFR 319.37-8 will be 

effective in managing the risk associated with these pests.
4

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Table 2. Discussion of pest risk management measures for quarantine pests that may follow the pathway on Oncidium plants in growing 

media from Taiwan

Pests Measures Reason References

All * All mother stock must 

be inspected and found 

free from evidence of 

pests and diseases by an 

APHIS inspector or 

foreign NPPO inspector 

no more than 60 days 

prior to the time the 

article is established in 

the greenhouse

The use of clean mother stock is an essential component of 

ornamental plant production. This requirement may 

eliminate or reduce the initial introduction of pests and 

diseases into the plant production environment in the 

greenhouse.

Jarvis, 1992; Metcalf 

and Metcalf, 1993; 

Agrios, 1997; Kahn and 

Mathur, 1999; Mizell 

and Short, 1999; Jones 

and Benson, 2001; 

BAPHIQ, 2002; USDA, 

2012

All * Phytosanitary 

inspections, oversight, 

written agreements1and 

administrative measures

Improper production and handling practices are often the 

primary means by which pests are introduced and spread in 

the place of production. The phytosanitary inspections, 

oversight, written agreements and administrative measures 

included in 7 CFR 319.37-8 provide additional 

phytosanitary quality control and rigor over other measures, 

and reduce the possibilities of improper practices being 

employed. Phytosanitary inspections are widely recognized 

as an important part of a pest management program.

Kahn and Mathur, 

1999; Jones and 

Benson, 2001; USDA, 

2012

Arthropods:

Amsacta lactinea

* Growing in screened, 

enclosed greenhouses2

* Sanitation

* Pest management plan, 

including monitoring and 

control

* Use of clean growing 

media that have not been 

previously used and is 

safeguarded to prevent 

infestation1

* Inspection

Growing in screened, enclosed greenhouses, sanitation and 

the use of clean, approved growing media that have not been 

used previously reduce the likelihood of introducing the pest 

into the greenhouse. A pest management plan must be 

implemented and should include monitoring, inspections for 

signs of infestation, and pest control as appropriate.

Damage caused by early instars can be detected as 

chlorophyll-free, whitish leaves, with the network of veins 

intact. Heavy foliar damage indicates the presence of lateinstar larvae, which are reddish brown with tufts of long 

hair, and which can be readily detected against the green 

background of the plants. Minute pellets of larval excreta 

Santacroce, 1991; 

Metcalf and Metcalf, 

1993;CABI, 2012; 

USDA, 2012
10

Pests Measures Reason References

and/or early instars feeding in large numbers on the 

undersurface of leaves are also visible. The eggs are laid in 

grouped rows of 6-22 eggs, which render their detection 

easier. Adults of Amsacta spp. are poor fliers.

Scirtothrips dorsalis

Thrips palmi

* Sanitation

* Pest management plan, 

including monitoring and 

control

* Use of clean growing 

media that have not been 

previously used and is 

safegurded to prevent 

infestation1

* Inspection

Thrips are small, can hide in pseudobulb scales and leaf 

sheaths of Oncidium plants, and may therefore not be easily 

detected by visual inspection alone. However, plant material 

can be carefully examined for signs of thrips, such as scars 

and deformities.

Thrips can pupate in leaf litter and soil. Therefore, general 

sanitation must be maintained and only APHIS-approved 

growing media must be used, which must be clean and not 

previously used. 

A pest management plan must be implemented, and should 

include monitoring, inspections for signs of infestation, and 

pest control as appropriate. Chemical control has been used 

against thrips, although repeated applications of insecticides 

may be required to achieve acceptable levels of control.

Sakimura et al., 1986; 

Santacroce, 1991; 

Reddy et al., 2005; Seal 

et al., 2006; EPPO, 

1989, 2011; CABI, 

2012; USDA, 2012; 

Spodoptera litura * Growing in screened, 

enclosed greenhouses2

* Sanitation

* Pest management plan, 

including monitoring and 

control

* Use of clean growing 

media that have not been 

previously used and is 

safeguarded to prevent 

infestation1

* Inspection

The moths are 15-20 mm long, with a wingspan of 30-38 

mm. They have a flight range of 1.5 km during a period of 4 

hours overnight, facilitating dispersion and oviposition on 

different hosts. Therefore, screened, enclosed greenhouses 

can prevent the moths from entering the production site and 

from ovipositioning on the plants and growing media.

The pests pupate in soil close to the plant. Therefore, general 

sanitation must be maintained and only APHIS-approved 

growing media must be used, which must be clean and not 

previously used.

The pest or signs of the pest can be detected through 

inspection. Newly hatched larvae can be detected by the 

“scratch” marks left on the leaf surface. Larvae feed 

Salama and Shoukry, 

1972; Santacroce, 1991; 

Matsuura and Naito, 

1992; Metcalf and 

Metcalf, 1993; EPPO, 

1997; Pogue, 2002; 

CABI, 2012; USDA, 

2012
11

Pests Measures Reason References

extensively on plants and can be up to 45 mm in length. 

Older larvae are night feeders and can be found in the soil 

around the base of the plants during the day. Eggs laid in 

clusters on the upper parts of the leaves can also be detected 

by inspection. However, eggs hidden between leaves, in 

media, or within flowers are more difficult to detect.

A pest management plan must be implemented, and should 

include monitoring, inspections for signs of infestation, and 

pest control as appropriate.

Tetranychus kanazawa * Plants may only enter 

the greenhouse as 

plantlets in tissue culture 

flasks or barerooted 

plants that have been 

thoroughly inspected and 

found free of plant pests 

and diseases1

* Sanitation

* Pest management plan, 

including monitoring and 

control

* Use of clean growing 

media that have not been 

previously used and is 

safeguarded to prevent 

infestation1

* Inspection

Spider mites may be spread be spread by the movement of 

infested plants or contaminated tools or clothing. Only 

plants that have been thoroughly inspected and found free of 

plant pests and diseases may enter the greenhouse. While the 

mites are smaller than the required mesh opening of 

exclusionary screens, the combination of the solid walls of 

the greenhouse and screens provide at least a partial barrier.

Spider mites often feed on the underside of the leaf. The 

upper surface of the leaf develops characteristic whitish or 

yellowish stippling. As mites move around, they spin 

webbing on leaves and stems. Heavy damage may cause leaf

drop, and the plant may be covered with webbing and die 

prematurely. Plants can be carefully examined for signs of 

mites.

Mites can drop from infested plants ad crawl on soil below. 

Heavily infested leaves may drop prematurely. Therefore, 

general sanitation must be maintained and only APHISapproved growing media must be used, which must be clean 

and not previously used. 

A pest management plan must be implemented, and should 

include monitoring, inspections for signs of infestation, and 

pest control as appropriate. Chemical control has been used 

CABI, 2012; Jones, 

2001; Masatoshi, 2002; 

Zhang, 2003
12

Pests Measures Reason References

against mites; although repeated applications of insecticides 

may result in resistance biological controls with pesticide 

resistant predators has been successfully used in Japan and 

Taiwan.

Mollusks:

Deroceras leave

Lissachatina fulica 

Laevicaulis alte 

Meghimatium bilineatum

Meghimatium pictum

Parmarion martensi 

Petalochlamys vesta

* Growing in screened, 

enclosed greenhouses2

* Sanitation

* Pest management plan, 

including monitoring and 

control

* Use of clean growing 

media that have not been 

previously used and is 

safeguarded to prevent 

infestation1

* Raised benches with 

copper plates wrapped 

around legs or equivalent

mollusk prevention 

measures1

* Inspection

* Packing materials and 

shipping containers are 

safeguarded from pest 

infestations1

Growing the plants in screened, enclosed greenhouses; 

sanitation and the use of clean, approved growing media 

reduce the likelihood of introducing the pest into the 

greenhouse. Growing plants in screened, enclosed 

greenhouses ensure absence of irrigation ditches or other 

openings through which the mollusks could gain access to 

the greenhouse. Sanitation measures such as freedom from 

soil and sand and using APHIS-approved growing media 

that have not been used previously reduce potential 

pathways for the entry of mollusks. APHIS-approved 

growing media are not good pathways for the movement of 

mollusks.

7 CFR 319.37-8 and the current Workplan for Phalaenopsis

in growing media from Taiwan require all plants to be 

grown on raised benches, which are at least 46 cm above the 

floor. The Workplan requires benches to be supported by 

legs that have copper plates wrapped around each leg, or an 

equivalent means of preventing mollusk infestations.

The pests have inefficient means of movement, move slowly 

from one site to another, and are generalist feeders spending 

little time searching for specific foods. Although many 

mollusks are herbivorous and considered agricultural pests, 

the majority of terrestrial gastropods feed on 

microorganisms associated with decaying vegetation. 

Sanitation measures such as removing plant debris and 

decaying vegetation, remove a source of feeding, especially 

for small juvenile and older mature mollusks; and assists in 

the reduction of pest populations.

Santacroce, 1991; 

Metcalf and Metcalf, 

1993; Bessin et al., 

1997; Speiser, 2001; 

Hollingsworth and 

Sewake, 2002; 

Robinson, 2002; CABI, 

2012; USDA, 2004, 

2011
13

Pests Measures Reason References

Larger mature and juvenile forms of these mollusks on 

plants can be detected by inspection. Mollusks can also be 

detected by slime trails, excrement, chewed leaves and 

lesions on plants. This would allow mollusks to be detected 

either before they enter the greenhouse or during required 

inspections. Small eggs in soil are difficult to detect, but this 

possibility is reduced by using clean, approved growing 

media that have not been previously used.

A pest management plan must be implemented, and should 

include monitoring, inspections for signs of infestation, and 

pest control as appropriate.

Bacteria:

Pectobacterium cypripedii

(Hori) Brenner et al.

* Sanitation

* Use of clean growing 

media that have not been 

previously used and is 

safeguarded to prevent 

infestation1

* Inspection

* The greenhouse is free 

of sand, soil, weeds, plant 

pests and debris;

* All plants are grown on 

raised benches

* Plants are watered only 

with rainwater that has 

been boiled or 

pasteurized, with clean 

well water, or with 

potable water

* Pest management plan, 

including monitoring and 

control

P. cypripedii may spread through compost or soil 

contaminated with infected plant debris. Soft rot bacteria 

like P. cypripedii spread through soil water and may be 

disseminated by water splash on to the leaves during 

watering or rainfall. Freedom from soil and raised benches 

reduce the possibility of water splash dissemination from 

contaminated soil or plant debris. The use of clean water 

sources may help prevent contamination.

The possibility that the pathogen may survive in growing 

media or plant debris is limited by the use of clean, 

approved growing media that have not been used previously, 

and sanitation measures such as disinfection and removal of 

plant debris.

P. cypripedii causes brown rot on orchids. Symptoms 

progress from small, water-soaked lesions into large brown, 

greasy-looking, slightly sunken areas. These lesions can 

become visible from both sides of the leaf. . Plants can be 

carefully examined for signs of brown rot disease.

Sanitation is very important to minimize the spread P. 

cypripedii to healthy plants. Control can also be achieved 

Anonymous, 2007; 

Bradbury, 1977; CABI, 

2012; Pérombelon and 

Kelman.1980
14

Pests Measures Reason References

with the use of bactericidal sprays applied as soon as 

symptoms are visible.

Fungi:

Bipolaris zizaniae

* Growing in screened, 

enclosed greenhouses2

* Pest management plan, 

including monitoring and 

control

* Use of clean growing 

media that have not been 

previously used and is 

safeguarded to prevent 

infestation1

* Inspection

Bipolaris zizaniae infects Zizania latifolia (Family: 

Poaceae) (water bamboo) and flower petals of Oncidium

spp. (Family: Orchidaceae). However, Oncidium is not a 

primary host for this fungus and a series of events has to 

occur for the pest to come in contact with suitable host 

material and establish a colony. Oncidium flower petals 

have only been found infected when Z. latifolia plants 

infected with B. zizaniae were naturally growing nearby 

orchid nurseries, and where environmental conditions were 

suitable for the survival of the fungus. 

Growing the Oncidium plants in a screened, enclosed 

greenhouse where sanitation and pest management measures 

are employed, reduces the likelihood of Oncidium flower 

petals coming into contact with infected Z. latifolia plants 

under conditions that favor the survival of the fungus.

A pest management plan must be implemented, and should 

include monitoring, inspections for signs of infection, and 

pest control as appropriate. The pest management plan 

should include measures to remove or control Z. latifolia

plants around greenhouses where Oncidium plants are 

grown. General sanitation measures must be maintained.

The possibility that the pathogen may survive in growing 

media or plant debris is limited by the use of clean, 

approved growing media that have not been used previously, 

and sanitation measures such as disinfection and removal of 

plant debris.

Spots on petals of Oncidium orchids can be detected by 

visual inspection. Infection studies of rice cultivars with 

various isolates of Helminthosporium oryzae (a closely 

Waggoner, 1973; 

Pirone, 1978; 

Santacroce, 1991; 

Vidhyasekaran, 1986, 

1991; Palm, 1994; 

Agrios, 1997; Hsieh et 

al., 2000; CABI, 2012; 

BAPHIQ, 2011; USDA, 

2012
15

Pests Measures Reason References

related species to B. zizaniae) indicated that the pathogen 

does not display dormancy and that inoculated plants readily 

express symptoms.

1 Entry of Phalaenopsis orchids as plants in growing media from Taiwan is authorized in 7 CFR 319.37-8 and a written agreement between APHIS 

and BAPHIQ has been in place since 2004 (USDA, 2004). In addition to the measures described in 7 CFR 319.37-8, the written agreement for 

Phalaenopsis orchis includes several other measures such as: plants may only enter the greenhouse as plantlets in tissue culture flasks or 

barerooted plants that have been thoroughly inspected and found free of plant pests and diseases; benches must have copper bands wrapped around 

each leg (or an equivalent means of preventing mollusk infestation); the growing media is stored and safeguarded in a manner that prevents any 

possible incursion by plant pests; and packing materials and shipping containers are safeguarded from pest infestations. If approved in 7 CFR 

319.37-8, a similar written agreement will be required for the importation of Oncidium orchids as plants in growing media from Taiwan.

2

7 CFR 319.37-8(e)(2)(ii) requires screening with openings of not more than 0.6 mm on all vents and openings except entryways. All entryways 

must be equipped with automatic closing doors. Screens and doors exclude the entry of flying or crawling pests that cannot fit through screens 

(Metcalf and Metcalf, 1993), and the greenhouse enclosure provides a physical barrier that reduces the exposure of the plants to rain and

windborne pests (Pirone, 1978; Agrios, 1997). The application of insect exclusion screens has proven to be a very effective measure to prevent 

primary pest infestation of protected environments (Weintraub and Berlinger, 2004).