Pest Risk Analysis for the Importation of Oncidium Orchid 

Plants, Oncidium spp., in Approved Growing Media 

From Taiwan into United States

May 7, 2012

Version 5

Agency contact

Center for Plant Health Science and Technology

Plant Epidemiology and Risk Analysis Laboratory

United States Department of Agriculture 

Animal and Plant Health Inspection Service

Plant Protection and Quarantine

1730 Varsity Drive, Suite 300

Raleigh, NC 27606-5202
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 ii

Executive Summary

In this pathway-initiated commodity pest risk analysis, we examine the risks associated with the 

proposed importation of Oncidium orchid plants(Oncidium spp.), in APHIS-approved growing 

media from Taiwan into the United States. The quarantine pests that are likely to follow the 

pathway are analyzed using the methodology described in our guidelines (PPQ, 2000), in which 

we examine pest biology in the context of the Consequences of Introduction and the Likelihood 

of Introduction, and estimate the baseline Pest Risk Potential. 

We identified fourteen quarantine pests that may follow the pathway on Oncidium spp. plants in 

growing media from Taiwan:

Order Taxonomy Pest Pest Risk Potential

Acari Arachnida-: Tetranychidae Tetranychus kanzawai Kishida High

Insecta Lepidoptera: Arctiidae Amsacta lactinea Cramer High

Lepidoptera: Noctuidae Spodoptera litura (F.) High

Thysanoptera : Thripidae Scirtothrips dorsalis Hood High

Thrips palmi Karny High

Mollusca Stylomatophora: 

Achatinidae

Lissachatina fulica (Bowdich) High

Stylomatophora: 

Agriliomacidae

Deroceras laeve (Müller) High

Stylomatophora: Parmarion martensi Simroth High

Helicarionidae Petalochlamys vesta (Pfeiffer) High

Stylomatophora: Meghimatium bilineatus (Benson) High

Philomycidae Meghimatium pictum Stoliczka High

Stylomatophora: 

Veronicellidae

Laevicaulis alte (Férussac, 1822) High

Bacteria Gammaproteobacteria: 

Enterobacteriaceae

Pectobacterium cypripedii (Hori) 

Brenner et al.

Medium

Fungi Ascomycetes: Pleosporales Bipolaris zizaniae Medium

We rated Bipolaris zizaniae and Pectobacterium cypripedii as Medium risk potential. All the 

others pests were given High pest risk potentials. Specific phytosanitary measures may be 

necessary for Medium risk pests, but are strongly recommended for pests with High risk 

potential (PPQ, 2000). In the pest risk management section of this document, we consider the 

manner in which regulations for the importation of plants in APHIS-approved growing media (7 

CFR § 319.37-8, 2009a) could reduce the pest risks associated with this importation. 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 iii

Table of Contents

Executive Summary...................................................................................................................... ii

1. Introduction............................................................................................................................... 1

2. Risk Assessment ........................................................................................................................ 1

2.1. Initiating Event: Proposed Action........................................................................................ 1

2.2. Assessment of the Weediness Potential of Oncidium spp. Plants....................................... 1

2.3. Current Status and Pest Interceptions.................................................................................. 2

2.4. Pest Categorization .............................................................................................................. 5

2.5. Analysis of Quarantine Pests............................................................................................. 16

2.6. Conclusion ......................................................................................................................... 32

3. Risk Management ................................................................................................................... 33

3.1. Introduction........................................................................................................................ 33

3.2. Systems Approaches.......................................................................................................... 33

3.3. General Program Requirements for Plants in Growing Media.......................................... 34

3.4. Evidence for the Effective Removal of Pests of Concern from the Pathway .................... 35

3.5. Program Safeguards to Ensure Compliance ...................................................................... 36

3.6. Conclusion ......................................................................................................................... 36

4. Authors..................................................................................................................................... 36

5. Literature Cited ...................................................................................................................... 36
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 1

1. Introduction

This pest risk analysis was prepared by the 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 (USDA, APHIS, 

PPQ, CPHST, PERAL) to examine the plant pest risks associated with the importation of 

Oncidium orchid plants in approved growing media from Taiwan into the United States. Taiwan 

is currently approved to export bare root orchid plants and Phalaenopsis in growing media to the 

USA under the 2004 approved work plan. Risk is characterized as high, medium or low, 

following version 5.02 of the PPQ Guidelines (PPQ, 2000) with supporting scientific evidence. 

The International Plant Protection Convention (IPPC) administered by the Food and Agriculture 

Organization (FAO) of the United Nations, provide both guidance for conducting pest risk 

assessments (IPPC, 2007: ISPM #2) and the use of biological and phytosanitary terms (IPPC, 

2007: ISPM #5). The terms and the methods used to initiate, conduct and report this assessment 

are consistent with these international guidelines. This document satisfies the requirements of the 

three stages of the FAO guidelines (Initiation, Risk Assessment, and Risk Management), and is 

consistent with applicable U.S. regulations, e.g. 7 CFR § 319.37-8(g). 

2. Risk Assessment

2.1. Initiating Event: Proposed Action

This commodity-based, pathway-initiated pest risk assessment was prepared in response to a 

request for USDA authorization to allow the importation of live Oncidium orchid plants 

established in APHIS-approved growing media from Taiwan. Bare-root orchid plants, including 

Oncidium spp., are generally enterable with appropriate documentation. Oncidium cut flowers 

are also enterable. Epiphytic plants (including orchid plants) are enterable established on 

approved materials in 7 CFR 319.37-8(d). Phalaenopsis orchids in growing media from Taiwan 

is approved in 7 CFR 319.37-8(e) requiring a phytosanitary certificate, CITES documentation, 

and inspection at a plant inspection station at the US port of entry by USDA, APHIS, PPQ 

inspectors. 

2.2. Assessment of the Weediness Potential of Oncidium spp. Plants

If the species considered for import poses a risk as a weed pest, then a “pest initiated” risk 

assessment is conducted. The results of the screening for weed potential for Oncidium orchid 

(Table 1) did not prompt a pest initiated risk assessment because plants already present in the 

United States are not reported as weeds. 

Table 1. Determining the Weediness Potential of Oncidium spp. Plants.

Commodity: Oncidium Sw. (Orchidaceae). A genus of 320 species of orchids from the 

subfamily Epidendroideae (Baker and Baker, 2006), native to tropical North, Central, and South 

America, and the Caribbean.

Phase 1: Consider whether the genus is new to or not widely prevalent in the United 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 2

States (exclude plants grown under USDA permit in approved containment facilities)

Oncidium is widely cultivated in greenhouses in Florida and other places in the United States.

Phase 2: Answer Yes or No to the following questions:

Is the genus listed in:

NO Geographical Atlas of World Weeds (Holm et al., 1979)

NO World's Worst Weeds (Holm et al., 1977)

NO Report of the Technical Committee to Evaluate Noxious Weeds; Exotic Weeds for 

Federal

Noxious Weed Act (Gunn and Ritchie, 1982) 

NO Economically Important Foreign Weeds (Reed, 1977)

NO Weed Science Society of America list (WSSA, 2007)

NO Do any literature references indicate weed potential, e.g., AGRICOLA, CAB, Biological 

Abstracts, AGRIS; search on "Oncidium” combined with "weed").

Phase 3: Conclusion: Some species of this genus are present in the United States and the 

answer to all of the questions is “No,” therefore, the commodity does not have 

weediness potential.

2.3. Current Status and Pest Interceptions

Taiwan has not previously requested access for Oncidium spp. plants for planting rooted in 

APHIS-approved growing media. Bare-root orchid plants, including Oncidium spp., are 

generally enterable with appropriate documentation. Oncidium cut flowers are also enterable.

Epiphytic plants (including orchid plants) established on coconut fiber, coconut husks, tree fern 

slabs, new clay pots, and new wooden baskets are allowed entry from Taiwan into the United 

States (7 CFR § 319.37-8, 2009b) Phalaenopsis in growing media from Taiwan is approved in 7 

CFR 319.37-8(e) requiring a phytosanitary certificate, CITES documentation, and inspection at a 

plant inspection station at the US port of entry by USDA, APHIS, PPQ inspectors. We report 

pests intercepted between 1985-2009 at U.S. ports-of-entry (Table 2) (PestID, 2010), and discuss 

them later (Section 2.5). Seventy two pests were intercepted on Oncidium orchids during this 

period (Table 2), including seventeen pathogens, twelve insects, six mites, and three mollusks. 

Most interceptions were in permit cargo at California ports. Pests identified only to the family 

level were generally not considered in the pest categorization list. This and other considerations 

are discussed in relation to the pest list (Table 3) below. 

Table 2. Pests intercepted on Oncidium spp. from Taiwan at U.S. ports-of-entry between 1985 

and 2010 (PestID, 2010)

Pest State Interception 

datea

Host 

part

Where 

intercepted

Imported 

as

Material for

Alphitobius diaperinus

(Panzer) (Tenebrionidae) 

CA Sep-06 Permit cargo Plant Propagation

Aphididae CA May-86 Flower Quarters Cut flower Non-entry

Aphididae CA Feb-96 (2) Flower Permit cargo Plant Propagation

Aphididae NY Jan-09 Flower Permit cargo Cut flower Consumption
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 3

Pest State Interception 

datea

Host 

part

Where 

intercepted

Imported 

as

Material for

Aphis gossypii Glover 

(Aphididae) 

CA Apr-99 Baggage Cut flower Consumption

Archipini species of

(Tortricidae)

NY Jan-09 Flower Permit cargo Cut Flower Consumption

Ascochyta sp. 

(Coelomycetes)

CA Nov-07 Permit cargo Plant Consumption

Bradybaena similaris

(Férussac) 

(Bradybaenidae) 

CA Apr-03 Permit cargo Plant Propagation

Bradybaena similaris

(Férussac) 

(Bradybaenidae) 

NY Jun-09 Flower Permit cargo Plant Consumption

Bradybaena sp. 

(Bradybaenidae)

CA Mar-97 Leaf Permit cargo Leaf Propagation

Brevipalpus sp. 

(Tenuipalpidae)

CA Jul-01 Permit cargo Plant Propagation

Cardiocondyla emeryi 

Forel (Formicidae) 

CA Feb-02 Permit cargo Plant Propagation

Coccidae CA Dec-06 Permit cargo Plant Propagation

Coccidae CA Dec-09 Mail Plant Propagation

Colletotrichium crassipes 

(Speg.) Arx 

(Coleomycetes) 

CA Aug-02 Permit cargo Plant Propagation

Colletotrichium crassipes 

(Speg.) Arx 

(Coleomycetes) 

FL Jul-02 Leaf Permit cargo Plant Propagation

Colletotrichium sp.

(Coleomycetes)

CA Sep, Dec-01, 

May-04 

Leaf Permit cargo Plant Propagation

Colletotrichium sp.

(Coleomycetes)

CA Aug-03 Permit cargo Plant Propagation

Deroceras laeve

(Agriolimacidae) 

CA Nov-99 Permit cargo Plant Propagation

Dichromothrips 

phalaenopsidis*Saki

mura (Thripidae)

CA Feb-96 Leaf Permit cargo Plant Propagation

Dydimosphaeria sp. 

(Dydimosphaeriaceae)

CA May-98 Stem Permit cargo Plant Propagation

Frankliniella intonsa

(Tybrom)(Thripidae)

NY May-10 Flower Permit cargo Cut Flower Consumption

Fusicoccum sp.

(Coelomycetes)

CA May-08 Leaf Mail Plant Propagation

Glomerella sp. 

(Glomerellaceae)

CA Aug-94 Permit cargo Plant Propagation

Halothrips chinensis* 

Priesner (Thripidae) 

NY Jan-09 Flower Permit cargo Cut Flower Consumption
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 4

Pest State Interception 

datea

Host 

part

Where 

intercepted

Imported 

as

Material for

Leptosphaeria sp. 

(Leptosphaeriaceae) 

CA Oct-96 Leaf Permit cargo Leaf Propagation

Macrophoma sp. 

(Coelomycetes) 

CA Sep-96 Leaf Permit cargo Plant Propagation

Microsphaeropsis sp. 

(Coelomycetes)

CA Jan-01 Permit cargo Leaf Propagation

Microsphaeropsis sp. 

(Coelomycetes)

CA Sep-02 Stem Permit cargo Plant Propagation

Mycosphaerella sp.

(Mycosphaerellaceae) 

CA Aug, Sep, 

Oct-96 

Leaf Permit cargo Plant Propagation

Mycosphaerella sp.

(Mycosphaerellaceae) 

CA May-05 Permit cargo Plant Propagation

Mycosphaerella sp.

(Mycosphaerellaceae) 

CA Mar-07 Stem Permit cargo Plant Propagation

Myzus persicae

(Aphididae) 

CA Apr-99 Baggage Cut flower Propagation

Neotarsonemoides sp. 

(Tarsonemidae) 

CA May-07 Leaf Permit cargo Cut flower Propagation

Noctuidae HI Jun-86 Flower Baggage Cut flower Consumption

Noctuidae NY Oct-08 Flower Permit cargo Cut flower Consumption

Noctuidae NY Jul-09 Flower Permit cargo Cut flower Consumption

Noctuidae NY Mar-10 Flower Permit cargo Cut flower Consumption

Ophiodotella sp. 

(Phyllacoraceae)

CA Jan-01 Permit cargo Leaf Propagation

Ophiodotella orchidearum

(Phyllacoraceae)

CA Jul-07 Permit cargo Leaf Propagation

Phaeosphaeria sp. 

(Phaeosphaeriaceae)

CA Jan-01 Permit cargo Plant Propagation

Phoma sp. (Coelomycetes) CA Aug-96, 

Aug-03

Permit cargo Plant Propagation

Phoma sp. (Coelomycetes) CA Apr-97 Stem Permit cargo Plant Propagation

Phoma sp. (Coelomycetes) CA Oct-96 Leaf Permit cargo Plant Propagation

Phomopsis sp.

(Coelomycetes)

CA May-97 Stem Permit cargo Plant Propagation

Phomopsis sp. 

(Coelomycetes)

CA Jul-02, Jul04, Mar-05, 

Oct-07

Leaf Permit cargo Plant Propagation

Phomopsis sp. 

(Coelomycetes)

CA Jun, Aug-02 Permit cargo Plant Propagation

Phomopsis sp.

(Coelomycetes)

CA Jul-09 Stem Mail Plant Propagation

Planococcus minor

(Pseudococcidae)

CA Feb-10 Flower Permit cargo Cut flower Consumption

Pseudococcidae NY Jan-09 Flower Permit cargo Cut flower Propagation
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 5

Pest State Interception 

datea

Host 

part

Where 

intercepted

Imported 

as

Material for

Pseudomonas sp.

(Pseudomanaeae)

FL Aug (2) 07, 

Sep-07, 

May-08

Leaf Permit cargo Plant Propagation

Pseudoribillardia sp. CA Aug-05 Permit cargo Plant Propagation

Psocoptera NY Feb-09 Flower Permit cargo Cut flower Propagation

Saissetia coffeae (Walker) CA Jul-01 Permit cargo Plant Propagation

Saissetia coffeae (Walker) CA Apr-99 Permit cargo Plant Propagation

Sminthuridae CA Apr-03, Jul02, Aug-02Permit cargo Plant Propagation

Spodoptera litura* (F.) 

(Noctuidae)

CA Oct-04 Flower Permit cargo Cut flower Consumption

Spodoptera litura* (F.) 

(Noctuidae)

NY Jul-07, May10Flower Permit cargo Cut flower Consumption

Spodoptera litura *(F.) 

(Noctuidae)

NY Jun, Jul-10 Flower Permit cargo Cut flower Consumption

Spodoptera sp. (Noctuidae) NY Sep-08 (2) Flower Permit cargo Cut flower Consumption

Tarsonemidae CA May-07 Leaf Permit cargo Plant Propagation

Tarsonemus bilobatus

Suski (Tarsonemidae) 

CA Apr-03 Permit cargo Plant Propagation

Thrips palmi*Karny 

(Thripidae)

NY Jan-09 (2) Flower Permit cargo Cut flower Consumption

Tydeus sp. (Tydeidae) CA Apr-03 Permit cargo Plant Propagation

Xenotarsonemus sp. 

(Tarsonemidae)

CA Apr-03 Permit cargo Plant Propagation

Zonitoides arboreus (Say) 

(Gastrodontidae) 

CA May-98, Jul99, Aug-03, 

Jun-05, Apr06

Permit cargo Plant Propagation

Zonitoides arboreus (Say) 

(Gastrodontidae) 

FL Aug-00 (2) Permit cargo Plant Propagation

Zonitoides arboreus (Say) 

(Gastrodontidae) 

FL Mar-02 Bulb Permit cargo Plant Consumption

Zonitoides arboreus (Say) 

(Gastrodontidae) 

FL Apr-02 Leaf Permit cargo Cutting Propagation

Zonitoides arboreus (Say) 

(Gastrodontidae) 

FL Dec-10 Permit cargo Plant Propagation

a Year (x) = Year (number of interceptions) 

*Reportable pest.

2.4. Pest Categorization

Here we determine whether or not pests are quarantine pests. First, we develop a comprehensive 

list of potential quarantine pests known to occur in the country or region from which the 

commodity is to be exported, which are associated with the commodity. To be a quarantine pest 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 6

ISPM #5 (IPPC, 2007), the organism must be “A pest of potential economic importance to the 

area endangered thereby and not yet present there, or present but not widely distributed and 

being officially controlled” . Because all pests on the list are associated with the plant species, 

they are considered to be “of potential economic importance” (IPPC, 2007). The listed pests may

or may not also occur in the United States. 

We list pests associated with Oncidium orchids in Taiwan below (Table 3). We produced the list 

based on information provided by the Bureau of Animal and Plant Health Inspection and 

Quarantine (BAPHIQ) of Taiwan, and our review of the scientific literature. In this list we 

identify (1) the presence or absence of these pests in the United States, (2) the generally affected 

plant part or parts, (3) the quarantine status of the pest with respect to the United States, (4) the 

likelihood of the pest following the pathway on commercially imported Oncidium orchids, and 

(5) pertinent citations for the distribution or the biology of the pest. We shaded rows containing

quarantine pests likely to follow the pathway and selected for further analysis.

Even if non-quarantine pests are able to follow the pathway, phytosanitary measures against 

these pests would not be justified. Therefore, for those pests we do not need information on plant 

part association and whether the pest is likely to follow the pathway. Accordingly, in those cases 

we put N/A (= Not Applicable) in the columns for “Plant Part(s) Association” and “Likely to 

Follow Pathway.” 

Table 3. Pests of Oncidium orchids in Taiwan. For every pest listed, the host was Oncidium sp. unless 

otherwise noted

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

ARTHROPODA

ACARI

Tarsonemidae

Neotarsonemoides sp. TW, US No N/A N/A Lin and Zhang, 1999; 

PestID, 2010; Beer, 1960

Tarsonemus bilobatus

2

(Suski)

TW, US No N/A N/A Gill et al., 2003; Lin and 

Zhang, 1999; PestID, 2010

Tenuipalpidae

Brevipalpus sp. TW, US No N/A N/A Miranda et al., 2007; 

PestID, 2010; Rodrigues et 

al., 2008

 

1 TW= Taiwan, US= United States, CA= California, FL= Florida, GA= Georgia, HI= Hawaii, PR= Puerto Rico, TX= Texas, 

VI= Virgin Islands.

2 The Tarsonemus bilobatus mite feeds on fungus. The mite can then move the fungus around the greenhouse to additional 

plants (Gill et al., 2003). Thus, this pest may be present on the commodity but is not directly associated with it. 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 7

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Tenuipalpus pacificus Baker TW,US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; Denmark, 

2006; Migeon and Dorkeld, 

2006; Wen et al., 2007;

Gleason and Morishita, 

1968; Wolcott, 1948; 

PestID, 2012

Tetranichidae

Tetranychus kanzawai 

Kishida 

TW, US Yes (PR, 

HI)

Leaf, 

Stem

Yes BAPHIQ, 2007; Anderson 

and Dixon, 2008; CABI, 

2011; Migeon and Dorkeld, 

2006; Navajas et al., 2001; 

PestID, 2012

Tydeidae

Tydeus sp. TW, US No N/A N/A PestID, 2010; Kerns, 2003; 

McCoy et al., 1969

INSECTA

Coleoptera: Tenebrionidae

Alphitobius diaperinus

(Panzer) 

TW, US (HI, 

PR)

No N/A N/A CABI, 2011; PestID, 2010; 

Cuckler and Alicata, 1944

Hemiptera: Aphididae

Aphis gossypii (Glover) TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; CABI, 

2011; PestID, 2010

Myzus persicae (Sulzer) TW, US (HI, 

PR)

No N/A N/A CABI, 2011; PestID, 2010

Hemiptera: Coccidae

Coccus hesperidum (L.) TW, US (HI, 

PR)

No N/A N/A CABI, 2011; Maes, 2004

Saissetia coffeae (Walker) 

(Signoret)

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; CABI, 

2011; Garland and Dixon, 

2003; Hollingsworth, 2005; 

PestID, 2010; TARI, 2009; 

Wen et al., 2007

Hemiptera: Diaspididae

Chrysomphalus aonidum 

(Linnaeus) 

TW, US (HI, 

PR)

No N/A N/A Ben-Dov et al., 2001; 

CABI, 2011; Miller and 

Davidson, 2005; TARI, 

2009; Watson, 2009;

PestID, 2012

Chrysomphalus 

dictyospermi (Morgan)

TW, US (HI, 

PR) 

No N/A N/A Ben-Dov et al., 2001; BioNica, 2009; CABI, 2011;

Maes, n.d.; PestID, 2012
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 8

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Diaspis boisduvalii Signoret TW, US (PR, 

HI) 

No N/A N/A Ben-Dov et al., 2001; 

Granara De Willink and E., 

2003; Miller and Davidson, 

2005; TARI, 2009; PestID, 

2012

Diaspis bromeliae (Kerner) TW, US (HI, 

PR 

No N/A N/A Ben-Dov et al., 2001; 

Granara De Willink and E., 

2003; Miller and Davidson, 

2005; Watson, 2009; 

PestID, 2012; Sipes, 2000

Hemiberlesia lataniae

(Signoret) 

TW, US (HI, 

PR)

No N/A N/A Ben-Dov et al., 2001; 

CABI, 2011; Miller and 

Davidson, 2005; PestID, 

2012

Ischnaspis longirostris

(Signoret) 

TW, US (PR, 

HI)

No N/A N/A Ben-Dov et al., 2001; Miller 

and Davidson, 2005; 

PestID, 2012

Lindingaspis rossi (Maskell) TW, US (HI No N/A N/A Ben-Dov et al., 2001; Miller 

and Davidson, 2005; 

Watson, 2009; PestID, 2012

Parlatoria proteus (Curtis) TW,US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; Ben-Dov et 

al., 2001; Miller and 

Davidson, 2005; TARI, 

2009; Watson, 2009;

PestID, 2012

Pinnaspis buxi (Bouché) TW, US (HI, 

PR)

No N/A N/A Ben-Dov et al., 2001; Coile 

and Dixon, 1999; PestID, 

2012

Hemiptera: Pseudococcidae

Ferrisia virgata (Cockerell) TW, US (HI, 

PR)

No N/A N/A Ben-Dov et al., 2001; 

CABI, 2011; Inoue et al., 

2006; PestID, 2012

Planococcus minor

(Maskell)3

TW, US No N/A N/A Ben-Dov et al., 2001; Triology, 2010; PestID, 2012

Pseudococcus longispinus

(Targioni Tozzetti)

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; Ben-Dov et 

al., 2001; CABI, 2011; 

TARI, 2009; PestID, 2012

Hymenoptera: Formicidae

Cardiocondyla emeryi Forel TW, US (HI, 

PR)

No N/A N/A PestID, 2010; AntWeb, 

2009; HEAR, 2006

 

3 We found very little evidence for an association of Planococcus minor with Oncidium: just a single interception on a cut 

flower shipment (PestID, 2010). Typically, a single interception is insufficient evidence for a host association. Due to the 

broad host range of the pest (Ben-Dov et al., 2010), we included it in this list. 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 9

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Lepidoptera: Arctiidae

Amsacta lactinea Cramer TW Yes Yes Leaf, Flower BAPHIQ, 2007; TARI, 

2009

Lepidoptera: Noctuidae

Spodoptera sp. TW, US No N/A N/A PestID, 2010

Spodoptera litura (F.) TW, US (FL4, 

HI)

Yes Yes Leaf, Stem BAPHIQ, 2007; CABI, 

2011; Kumari and Lyla, 

2001; Meagher et al., 2008; 

PestID, 2010; Wen et al., 

2007

Orthoptera: Acrididae

Atractomorpha psittacina de 

Haan

TW Yes No 5 Leaf, Stem, 

Flowers

BAPHIQ, 2007; Wen et al., 

2007 TARI, 2009

Thysanoptera: Thripidae 

Thrips hawaiiensis

(Morgan)

TW, US (HI, 

PR

No N/A N/A BAPHIQ, 2007; PestID, 

2012

Thrips palmi Karny TW, US (FL, 

HI, PR)

Yes Yes6Flowers PestID, 2010; Breithaupt, 

2010

Scirtothrips dorsalis Hood TW, US (FL, 

GA, HI, TX 

PR)

Yes Yes Flowers Diffie et al., 2008; EPPO, 

1997a; APHIS-USDA, 

2006; Kumar et al., 2010

MOLLUSCA

Achatinidae

Lissachatina fulica 

(Bowdich) 

[Syn; Achatina fulica 

Bowdich]

TW, US (FL: 

eradicated;

HI)

Yes Yes Flower, Leaf, 

Stem, Roots

BAPHIQ, 2007; CABI, 

2011; Chao et al., 1994; 

Wen et al., 2007; WhiteMcLean, 2011

Agriolimacidae

Deroceras laeve (Müller) TW, US (HI) Yes (PR) Yes Flower, Leaf, 

Stem, Roots

PestID, 2010; WhiteMcLean, 2011

Bradybaenidae 

Bradybaena similaris 

(Férussac)

TW, US (HI, 

PR)

No N/A N/A PestID, 2010; BAPHIQ, 

2007; Chao et al., 1994; 

GSMFC, 2003; Taketani, 

1936; Wen et al., 2007;

Capinera and White, 2011; 

White-McLean, 2011

 

4 One male Spodoptera litura was trapped in a greenhouse in Florida in 2007. Subsequent intensive surveys with pheromone 

lures have failed to collect this moth again (Meagher et al., 2008).

5 This pest is a large, active, winged insect that may feed on the plants, but is highly unlikely to be associated with it during 

handling and shipping.

6

From approximately 12,200 interceptions of T. palmi from different countries only two of them were from Taiwan on cut 

flowers. The numbers of interceptions on Oncidiums from other countries besides Taiwan (Thailand) are more frequent in 

this commodity, indicating a potential pathway. We will consider this pest for further analysis.
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 10

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Helicarionidae

Parmarion martensi Simroth TW, US (HI) Yes (PR) Yes Flower, Leaf, 

Stem, roots

BAPHIQ, 2007; NAPIS, 

2009; Qvarnstrom et al., 

2007; White-McLean, 2011

Petalochlamys vesta 

(Pfeiffer)

TW Yes Yes Flower, Leaf, 

Stem, roots

BAPHIQ, 2007; Taketani, 

1936

Lymnaeidae

Austropeplea ollula Gould TW, US (HI) No7 N/A N/A BAPHIQ, 2007; Cliver and 

Fayer, n.d.

Lymacidae

Limacus flavus (Linnaeus, 

1758) 

Syn: Limax flavus

Linnaeus

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; GSMFC, 

2003; PestID, 2010; WhiteMcLean, 2011

Philomycidae

Meghimatium bilineatum 

(Benson) 

Syn: Incilaria bilineata

(Benson)

TW, US (HI) Yes, PR Yes Flower, Leaf, 

Stem, roots

BAPHIQ, 2007; Chao et al., 

1994; Cowie, 1997

Meghimatium pictum

Stoliczka,

TW Yes Yes Flower, Leaf, 

Stem, roots

BAPHIQ, 2007

Veronicellidae

Laevicaulis alte (Férussac, )

Syn: Vaginulus alte

Férrussac

TW,US (HI) Yes, PR Yes Flower, Leaf, 

Stem

BAPHIQ, 2007; Chao et al., 

1994; Wen et al., 2007; 

White-McLean, 2011

Zonitidae

Zonitoides arboreus (Say) TW, US (HI, 

PR)

No N/A N/A GBIF., 2010; PestID, 2010; 

RBC, 2010; Karlin, 1956, 

BACTERIA8

Acidovorax avenae subsp. 

cattleyae (Pavarino) 

Willems et al., 1992

comb. no. 

[Betaproteobacteria, 

Comamonadaceae]

TW, US (HI, 

PR)

No N/A N/A Baker and Baker, 2006; 

BAPHIQ, 2007; Bradbury, 

1986; CABI, 2011; Hsieh, 

n.d.; OEPP/EPPO, 2008; 

Saddler, 1994a; Schaad et 

al., 2008; CISFH, 2011; 

CABI, 2011

Burkholderia gladioli pv 

gladioli (Severini 1913) 

Yabuuchi et al. 1993, 

[Betaproteobacteria, 

Burkholderiaceae]

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; Bradbury, 

1986; Saddler, 1994b; 

CABI, 2011; Ura et al., 

2006

 

7

Species within the family are fresh water snails and are not quarantine significant.

8 Taxonomy according to Euzéby, 2007)
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 11

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Pectobacterium 

carotovorum subsp. 

carotovorum (Jones, 

1901) Hauben et al. 1999. 

Syn: Erwinia carotovora

subsp. carotovora (Jones) 

Bergey et al.1923 

[Gammaproteobacteria, 

Enterobacteriaceae]

TW, US (HI, 

PR)

No N/A N/A Anonymous, 2006; 

BAPHIQ, 2007; Baker and 

Baker, 2006; Bradbury, 

1986; CABI, 2011; Su and 

Lue, 1992

Dickeya chrysanthemi

(Burkholder et al. 1953) 

Samson et al. 2005. Syn: 

Erwinia chrysanthemi

Burkholder et al. 

[Gammaproteobacteria, 

Enterobacteriaceae]

TW, US (PR, 

HI) 

No N/A N/A Baker and Baker, 2006; 

EPPO, 1997b; Lee et al., 

2006; CABI, 2011

Dickeya zeae Samson et al. 

2005. Syn: Erwinia 

chrysanthemi pv. zeae

(Sabat) Victoria, 

Arboleda & Munoz 

(Enterobacteriaceae) 

[Gammaproteobacteria, 

Enterobacteriaceae]

TW, US (PR, 

HI)

No N/A N/A Anonymous, 2006; 

BAPHIQ, 2007; Bradbury, 

1986; CABI, 2011

Pectobacterium cypripedii 

(Hori) Brenner et al. 

[Gammaproteobacteria, 

Enterobacteriaceae]

TW, US (HI) Yes (PR) Yes Root, Stem, 

Leaves

Anonymous, 2006; 

Bradbury, 1986; CABI, 

2011; Kado, 2006; Simone 

and Burnett, 1995; CISFH, 

2011

Pseudomonas sp. 

[Gammaproteobacteria: 

Pseudomonales]

TW, US No N/A N/A PestID, 2010

FUNGI9

Ascochyta sp. [Fungi 

Imperfecti: 

Colelomycetes]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Bipolaris maydis (Y. Nisik.) 

Shoemaker [Ascomycete: 

Pleosporales]

TW, US (HI, 

PR)

No N/A N/A CABI, 2011; Hsieh et al., 

2000; Farr and Rossman, 

2011; CISEH, 2011

 

9 Taxonomy according to Farr and Rossman (2011)
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 12

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Bipolaris oryzae (Breda de 

Haan) Shoemaker 10

[Ascomycete: 

Pleosporales]

TW, US (HI, 

PR)

No N/A N/A CABI, 2011; Hsieh et al., 

2000; Farr and Rossman, 

2011; Gonsalves and 

Ferreira, 1994a

Bipolaris zizaniae (Y. 

Nisik.) Shoemaker 

[Ascomycetes: 

Pleosporales]

TW Yes11 Yes Flower BAPHIQ, 2007; Hsieh et 

al., 2000; Hsieh, n.d.; 

Simone and Burnett, 1995

Botrytis cinerea Pers.: Fr. 

[Botryotinia fuckeliana

(de Bary) Whetzel] 

[Ascomycetes: 

Helotiales])

TW, US (HI, 

PR)

No N/A N/A Baker and Baker, 2006; Farr 

and Rossman, 2011; Hsieh, 

n.d.

Colletotrichum crassipes

(Speg.) Arx 

[Ascomycetes: 

Phyllachorales] 

TW US (HI, 

PR)

No N/A N/A Gonsalves and Ferreira, 

1994b; Farr and Rossman, 

2011; PestID, 2010

Colletotrichum 

gloeosporioides (Penz.) 

Penz. & Sacc. In Penz. 

[teleomorph: Glomerella 

cingulata (Stoneman) 

Spauld. & H. Schrenk] 

[Ascomycetes: Incertae 

sedis]

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; CABI, 

2011; Farr and Rossman, 

2011; Rivera-Coto and 

Corrales-Moreira, 2007; 

PestID, 2010; Simone and 

Burnett, 1995

Colletotrichium sp. [Fungi 

Imperfecti, 

Coelomycetes]

TW, US No N/A N/A PestID, 2010

Didymosphaeria sp.

[Ascomycetes: 

Pleosporales]

TW, US No N/A N/A Farr and Rossman, 2011;

PestID, 2010

 

10 This is proposed by Shimizu et al., 1998 as a synonym of Bipolaris leersiae (Atk.) Shoem. and B. zizaniae ( Y. Nisik.) 

Shoemaker (Shimizu et al., 1998), Because this synonymy is not yet officially recognized by the ICBN, we treated them as 

separate species here.

11 Scientific literature indicates that B. zizaniae and B. oryzae should be considered one species. Intercross fertility among H. 

oryzae and H. zizaniae (Chang, 1974) is evidence that these species should be considered as one species. In a similar 

study, Tsuda (1987) showed in mating studies that B. oryzae, B. leersiae, and B. zizaniae were sexually compatible and

concluded that they were all conspecific. In addition, B. oryzae from rice, B. maydis from corn, and Bipolaris sp. from 

bamboo caused similar brown spot symptoms on petals of the inoculated Oncidium in pathogenicity tests (Hsieh et al., 

2000). Based on currently available scientific evidence, we believe B. leersiae, B. oryzae and B. zizaniae are the same 

species. Because this synonymy has not been recognized by the ICBN, we treated them as separate species here. 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 13

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Fusarium oxysporum

Schltdl. ; Fr. 

[Ascomycetes: 

Hypocreales]

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; Baker and 

Baker, 2006; CABI, 2011; 

Simone and Burnett, 1995; 

Farr and Rossman, 2011; 

Rivera-Coto and CorralesMoreira, 2007

Fusicoccum sp. [Fungi 

Imperfecti, 

Coelomycetes]

TW, US No N/A N/A PestID, 2010

Glomerella sp. 

[Ascomycetes: Incertae 

sedis]

TW, US No N/A N/A PestID, 2010

Leptosphaeria sp. 

[Ascomycete: 

Pleosporales]

TW, US No N/A N/A Farr and Rossman, 2011;

PestID, 2010

Macrophoma sp. [Fungi 

Imperfecti, 

Coelomycetes]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Microsphaeropsis sp.

[Ascomycetes: 

Pleosporales]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Mycosphaerella sp.

[Ascomycetes: 

Mycosphaerellales]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Ophiodothella sp. 

[Ascomycetes: 

Phyllachorales]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Phaeosphaeria sp. 

[Ascomycetes: 

Diaporthales]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Phoma sp. [Fungi 

Imperfecti, 

Coelomycetes]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Phomopsis sp. [Fungi 

Imperfecti, 

Coelomycetes]

TW, US No N/A N/A Farr and Rossman, 2011; 

PestID, 2010

Pseudorobillarda sp. 

[Ascomycetes: Incerta 

sedis]

TW, US No N/A N/A PestID, 2010

Phytophthora cactorum

(Lebert & Cohn) J. 

Schröt. [Oomycetes: 

Pythiales]

TW, US (HI, 

PR)

No N/A N/A Baker and Baker, 2006; 

CABI, 2011; Cating et al., 

2009; Farr and Rossman, 

2011
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 14

Pest Distribution1 Quarantine pestFollow 

pathway

Plant part 

affected

References

Phytophthora nicotianae

Breda de Haan var. 

parasitica (Dastur) G. M. 

Waterhouse [Oomycetes: 

Pythiales]

TW, US (HI, 

PR, VI)

No N/A N/A CABI, 2011; Erwin and 

Ribeiro, 1996; Farr and 

Rossman, 2011; Hsieh, 

1984; Hsieh, n.d.

Phytophthora palmivora

(Buttler) Buttler 

[Oomycetes: Pythiales]

TW, US (HI, 

PR; VI)

No N/A N/A BAPHIQ, 2007; CABI, 

2011; Cating et al., 2009; 

Erwin and Ribeiro, 1996; 

Farr and Rossman, 2011; 

Hsieh, n.d.; Tsai et al., 

2006

Pythium ultimum Trow 

[Oomycetes: Pythiales]

TW, US (HI, 

PR, VI)

No N/A N/A Baker and Baker, 2006; Farr 

and Rossman, 2011

Rhizoctonia solani Kühn 

Teleomorph: 

Thanatephorus cucumeris

(Frank) Donk 

[Basidiomycetes, 

Ceratobasidiales]

TW, US (HI, 

PR)

No N/A N/A Baker and Baker, 2006; 

CABI, 2011; Simone and 

Burnett, 1995

Sclerotium rolfsii Sacc. 

Teleomorph: Athelia 

rolfsii (Curzi) Tu & 

Kinbr. [Basidiomycetes: 

Polyporales])

TW, US (HI, 

PR

No N/A N/A BAPHIQ, 2007; Baker and 

Baker, 2006; CABI, 2011; 

Farr and Rossman, 2011 

VIRUSES

Cymbidium Mosaic Virus

(CymMV) 

TW, US (HI, 

PR)

No N/A N/A Baker and Baker, 2006; 

BAPHIQ, 2007; Brunt et al., 

1996; CABI, 2011; Tsai, 

n.d.

Cucumber Mosaic Virus

(CMV)

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2002; Brunt et 

al., 1996; CABI, 2011; 

Chang et al., 2003

Odontoglossum Ringspot 

Virus (ORSV) tobacco 

mosaic virus - orchid 

strain (= Odontoglossum 

ringspot tobamovirus)

TW, US (HI, 

PR)

No N/A N/A BAPHIQ, 2007; Baker and 

Baker, 2006; Brunt et al., 

1996; CABI, 2011; Pearson 

et al., 2006

Tomato Spotted Wilt Virus

(TSWV

TW, US (HI, 

PR)

No N/A N/A Brunt et al., 1996; CABI, 

2011; Chang et al., 2003; 

Hu et al., 1993; Simone 

and Burnett, 1995
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 15

2.4.1. Pests not considered for further mitigation

Other listed plant pests may be potentially detrimental to the agricultural systems of the United 

States; however, they were not subjected to further analysis for a variety of reasons. First, the 

pest’s primary association may be with plant parts other than the commodity. Secondly, the pests 

may not be associated with the commodity during transport or processing because of their 

inherent mobility and/or instinct to avoid light or human activity. Thirdly, sterile insect stages 

can be transported in a shipment but are unable to establish viable populations upon entry. 

Lastly, packing procedures and production systems at the country of origin may cause 

contamination by organisms not normally associated with Oncidium orchids. Should any of these 

biological contaminants be intercepted during inspection by PPQ Officers, quarantine action will 

be required (PestID, 2010). 

Pests not identified to species. The biological hazard of organisms identified only to the genus 

level is not directly assessed in this document. This applies to the genera Bradybaena 

(Mollusca), Brevipalpus, Neotarsonemoides, Xenotarsonemus, and Tydeus (Arthropoda), 

Spodoptera (Insecta), Ascochyta, Colletotrichum, Didymosphaeria, Fusicoccum, Glomerella, 

Leptosphaeria, Macrophoma, Microsphaeropsis, Mycopsphaerella, Ophiodotella, 

Phaeosphaeria, Phoma, Phomopsis, Pseudorobillarda (Fungi), and Pseudomonas (Bacteria), 

because of the uncertainty about the lack of species identifications. The IPPC No. 11 indicate 

that “The identity of the pest should be clearly defined to ensure that the assessment is being 

performed on a distinct organism, and that biological and other information used in the 

assessment is relevant to the organism in question” (IPPC, 2007: ISPM #2). The taxonomic level 

for organisms considered in risk assessments is usually the species. The use of a higher or lower 

taxonomic level should be supported by a scientifically sound rationale. In cases where levels 

below the species level are being analyzed, the rationale for this distinction should include 

evidence of reported significant variation in factors such as virulence, pesticide resistance, 

environmental adaptability, host range or its role as a vector (IPPC, 2007: ISPM #2). 

Pests not reliably associated with host or in country. Single or a few interceptions of known 

species of, Dichromothrips phalaenopsidis, Haplothrips chinensis, and Ophiodothella 

orchiodearum are not sufficient evidence of an association with Oncidium, or for their presence 

in Taiwan. Therefore we did not include them in the pest list above. If more interceptions occur 

later, we may re-evaluate their risk.

The genus Xenotarsonemus (Acari) also had insufficient evidence for its association with 

Oncidium or presence in Taiwan, so we did not include it on the list.

Some of the listed pests identified only to genus were associated with Oncidium only by

interceptions in cargo, passenger baggage, or mail at ports-of-entry. Some of the pests 

intercepted are biological contaminants that are not expected to be present in every shipment. For 

example, the reported hosts for Psocoptera species do not include Oncidium: these insects 

usually feed on fungal hyphae and spores, lichens, algae, bark, and plant debris, moreover, most 

psocids are woodland insects with little economic importance (Meyer, 2005; Kalinovic et al., 

2006). 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 16

2.4.2. Pests considered for further mitigation

Several arthropod pests were identified as quarantine pests likely to be imported with 

unmitigated shipments of Oncidium spp. orchids, possibly requiring phytosanitary measures to 

mitigate risk. We further analyzed fourteen quarantine pests, five arthropods, six mollusks, one 

bacterium, and one fungi (Table 4).

Table 4. Quarantine pests likely to follow the pathway on Oncidium plants in growing media 

from Taiwan.

Type Pest

Arthropods Amsacta lactinea

Scirtothrips dorsalis

Spodoptera litura

Tetranychus kanzawai

Thrips palmi

Mollusks Deroceras laeve

Lissachatina fulica

Laevicaulis alte

Meghimatium bilineata 

Meghimatium pictum

Parmarion martensi

Petalochlamys vesta

Bacteria Pectobacterium cypripedii

Fungi Bipolaris zizaniae

2.5. Analysis of Quarantine Pests

In this risk assessment we identify and characterize the main sources of uncertainty. These 

include the use of a developing or evolving process (PPQ, 2000; Orr et al., 1993), the approach 

used to combine risk elements (Bier, 1999; Morgan and Henrion, 1990), and the evaluation of 

risk by comparisons to lists of factors within the guidelines (Kaplan, 1992; Orr et al., 1993). To 

address this last source of uncertainty, the lists of factors were interpreted as illustrative and not 

exhaustive, implying that additional biological information, even if not explicitly part of the 

criteria, can be used when relevant to a rating. Other sources of uncertainty include the quality of 

the biological information and the amount of information available on the regional flora and 

fauna (Gallegos and Bonano, 1993) and the inherent biological variation within a population of 

organisms introduces uncertainty as well (Morgan and Henrion, 1990).

2.5.1. Consequences of Introduction

In this part of the analysis we consider the negative outcomes that may occur when the identified 

quarantine pests are associated with Oncidium orchids from Taiwan and are introduced into the 

United States. We rated the consequences of introduction for each pest according to the 

following five risk elements (PPQ, 2000): Climate–Host Interaction, Host Range, Dispersal 

Potential, Economic Impact, and Environmental Impact. These risk elements reflect the biology
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 17

of the pest and its hosts. For each risk element, we assigned pests a rating of Low (1), Medium 

(2), or High (3). We then calculate a cumulative risk value as the sum of the ratings for each pest. 

These ratings are helpful in interpreting detailed results; however, the ratings are considered 

supplemental information within the context of the overall risk analysis document. We 

summarized these ratings below for the analyzed pests.

Amsacta lactinea 

Climate/Host Interaction. This species is distributed over several subtropical and tropical 

countries including China, India, Korea, Laos, Malaysia, Myanmar, Taiwan, Thailand, Vietnam 

(CABI, 2011). These places correspond to Plant Hardiness Zones 9–11 of the continental United 

States (Fig. 1). (Magarey et al., 2008). The risk rating is Medium.

Host Range. The host range of A. lactinea is very wide. It feeds on virtually all cultivated and 

wild vegetation. Some affected host are Oncidium sp. (Orchidaceae) (BAPHIQ, 2007; TARI, 

2009), Arachis sp. (Peanut Crop Germplasm Committee, 2003), Leucaena leucocephala (Wu et 

al., 2007), Phaseolus sp., (Sharma and Ramamurthy, n.d.), Glycine sp. (Jayappa et al., n.d.), 

Camelia sinensis (Banerjee, 1987), Gossypium sp. (Gentry, 1965), Ligustrum sinennsis (Zhang et 

al., 2008), Oriza sp. (Maxwell-Lefroy, 1907; Gentry, 1965), Phragmites australis (Wen et al., 

2007; Maxwell-Lefroy, 1907; Gentry, 1965),_Helianthus annuus (IKISAN, 2009), Ocimun 

basilicum (Wen et al., 2007), and Sapium sebiferum (TARI, 2009). The numbers of plants 

attacked belong to the families Asteraceae, Euphorbiaceae, Fabaceae, Lamiaceae, Malvaceae, 

Oleaceae, Orchidaceae, Poaceae, Rosaceae, and Theaceae. The risk rating for the host range for 

this pest is High. 

Dispersal Potential. We found little information about dispersal potential for this species. 

Females of a similar species, A. moorei, may lay 500-1900 eggs during their life spans (CABI, 

2011). After eclosion, early instar larvae feed gregariously. Later instars spread throughout the 

field (CABI, 2011). Adults of A. moorei are poor fliers, but they are strongly attracted to 

artificial light–especially males (CABI, 2011). For A. lactinea raised in the laboratory on maize, 

the incubation period ranged from 3 to 4 days, the total larval period from 24.8±1.3 to 31±1 

days, and the total life cycle ranged from 35.8±2.3 days in the 1st generation (beginning of July

to end of August) to 252±4 days in the 3rd generation (mid-October to end of June) (Yazdani et 

al., n.d.). Hence, A. lactinea may have several generations per year. This pest has a high 

reproductive potential, but its dispersal could be considered low. For these reasons, we rated this 

risk element Medium.

Economic Impact. Amsacta lactinea may not be of significant impact on the ornamental 

production under greenhouse conditions, but if introduced on field crops it could cause damage 

and economic losses, e.g., the Peanut Crop Germplasm Committee (2003) rated the economic 

impact for this pest in peanuts growing areas as medium. Damage caused by a larva from a 

similar Amsacta sp. differs from crop to crop. Seedlings of certain crops (e.g., clusterbean, 

Cyamopsis tetragonolobus) are completely killed because the larvae feed on the soft stem rather 

than on leaves (CABI, 2011). Other crops, such as pearl millet (Pennisetum glaucum), mostly

survive damage.

If introduced, this pest could lower the yield of several crops of economic importance and may

cause plant mortality, but damages depend upon the type of crop and the growth stage affected. 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 18

Controlling this pest will increase production costs. The risk rating for the Economic Impact of 

this pest is High.

Figure 1. Plant Hardiness Zones potentially suitable for establishment by Amsacta lactinea, 

Laevicaulis alte, Meghimatium bilineatum, M. pictum, Parmarion martensi, Petalochlamys 

vesta, and Thrips palmi.

Environmental Impact. Hosts include species of Helianthus (IKISAN, 2009). This genus 

includes one endangered species, H. schweinitzii, and one threatened species, H. paradoxus, in 

the continental United States (50 CFR§17.12, 2005). Outbreaks would likely trigger increased 

chemical control programs. The risk rating for the Environmental Impact of this pest is High.

Bipolaris zizaniae

Climate-Host Interaction. Bipolaris zizaniae infects Zizania latifolia (Hsieh et al., 2000), so we 

would expect it to survive where Z. latifolia grows naturally and the environmental condition are 

suitable for its development. Zizania latifolia is present in: Asia in China, India, Japan, Korea, 

Taiwan, Myanmar, Russian Federation, Vietnam, and Australasia in New Zealand (GRIN, 2011), 

but B. zizaniae has only been reported from Taiwan (BCRC, 2004) and Japan (NBRC, 2004; 

NIAS Genebank, 2011), in areas corresponding to U.S. Plant Hardiness Zones 9-11 (PERAL, 

2008). The potential hosts for B. zizaniae occur in these zones (NRCS, 2011). This warrants a 

Medium risk rating for Climate-Host Interaction.

Host Range. Bipolaris zizaniae infects water bamboo (Zizania latifolia (Family: Poaceae)), and 

petals of Oncidium orchid (Oncidium sp. (Family: Orchidaceae)) (Hsieh et al., 2000). The fact 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 19

that Oncidium petals are only infected when Z. latifolia plants infected with B. zizaniae are 

nearby orchid nurseries (Hsieh et al., 2000) indicates that Oncidium is not a primary host for this 

fungus. Based on the above information the risk rating for Host Range is Medium.

Dispersal Potential. There is very little specific information on the biology of B. zizaniae. In 

general, Bipolaris species produce spores on infected tissue which are readily dispersed by rain 

splashing and wind (Waggoner, 1973). Spore production on helminthosprium infected leaves 

vary with host and environmental condition. Grainger (1954) studied the number of spores 

trapped at different highs from oats infected fields. The number of spores trapped during that test 

varied from 96 to 399 spores /100sq cu feet of air collected. Indicating that this H. avenae is very

prolific and easily dispersed by wind. On the other hand , this group of pathogens can survive for 

long time in debris and in the soil. For example, Cochliobolus miyabeanus (whose anamorph B. 

oryzae is closely related (or even synonymous) to B. zizaniae) can survive in infected plant 

residues for long time periods, but the source of most primary infection is infected seed (CABI, 

2011). Another species, Bipolaris sorokiniana can survive on wheat residues and in the soil for 

up to one year (Malaker et al., 2007). The duration of survival of B. zizaniae on Oncidium petals 

or debris is unknown. Based on the above information the risk rating for dispersal potential is 

High.

Economic Impact. It is difficult to determine the economic impact that Bipolaris zizaniae may

have on the U.S. agricultural industry. The host range of B. zizaniae is restricted to only two 

plant species, water bamboo (Z. latifolia), and petals of Oncidium orchids (Oncidium sp.) (Hsieh 

et al., 2000). There are no records of B. zizaniae infecting other Zizania species. Zizania. latifolia 

is not known to grow in the continental United States. Therefore, we assigned this species a Low 

risk rating for Economic Impact.

Environmental Impact. Bipolaris zizaniae may have direct or indirect impacts on plants listed 

as threatened or endangered in the United States. The only plant species that could be directly 

impacted by the introduction of B. zizaniae (if proven to be a host) is Zizania texana (NRCS, 

2011). Zizania texana only grows in the San Marcos River in Hays County, central Texas; 

Edwards Plateau region. Currently, only one population is known (Texas Parks and Wildlife 

Department, 2009). The likelihood of B. zizaniae in getting in contact with Z. texana (if proven 

been a host) is very low. Therefore, we assigned a Low risk rating for Environmental Impact.

Lissachatina fulica

Climate/Host Interaction. Most members of Achatinidae are tropical and subtropical, but some 

species, most notably A. fulica, can inhabit ranges far outside tropical areas. Lissachatina fulica

remains active at a temperature range of 9–29o C, and can survive temperatures as low as 2o C, 

and as high as 30o C (Raut and Barke, 2002). Large adults can aestivate for 10 months, while 

hatchling snails are restricted to about two months due to desiccation (PERAL, 2005).

Lissachatina fulica can survive cold conditions, even snow, by aestivating, though it is unable to 

establish itself in temperate regions (CABI, 2011). However, Raut and Barke (2002), based on 

the worldwide distribution of L. fulica, suggested that this snail is most closely associated with 

tropical and subtropical broadleaf forests. Because that kind of forest does not occur in the 

United States, much less than 1 percent of the area within the continental United States is 

suitable for its establishment.
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Ver. 5 May 7, 2012 20

Additionally, L. fulica is normally nocturnal and crepuscular in its habits, though it becomes 

active in the daytime during rainy or overcast periods. Thus, light, temperature, moisture, and 

food are all vital factors in snail activity (CABI, 2011). Conditions essential to the permanent 

survival of L. fulica do not seem to occur anywhere in the continental United States, no part of 

which is completely free at all times of winter frosts. In addition, most of the warmer areas are 

deficient in rainfall or lack protection against the sun (Raut and Barke, 2002). 

Overall, then, this snail is only likely to survive in Plant Hardiness Zones 10-11 (Fig. 1) (Raut 

and Barke, 2002; Magarey et al., 2008). Accordingly, we rated this risk element Low.

Host Range. Lissachatina fulica has a broad range of host plants: more than 200 plant species in 

about 40 families (Raut and Barke, 2002). Major hosts include Amaranthus sp.,(Amaranthaceae);

Alocasia sp., Colocasia sculenta, Xanthosoma brasiliensis (Araceae); Brassica oleracea

(Brassicaceae); Citrillus lanatus, Cucumis melo, C. sativus, Cucurbita maxima, C. pepo, Luffa 

sp.,(Cucurbitaceae); Arachis hypogea, Glycine max, Pisum sativum (Fabaceae); Allium cepa 

(Liliaceae); Gossypium sp (Malvaceae); Musa paradisiaca (Musaseae); Coffea arabica, C. 

canephora, (Rubiaceae); Citrus sinensis, C. reticulata (Rutaceae); Solanum melongena, 

Lycopersicum sculentum, Capsicum annun (Solanaceae); Theobroma cacao (Sterculiaceae); and 

Camellia sinensis (Theaceae), among others (Raut and Barke, 2002).

Young snails are most predacious on living vegetation, while very small and older individuals 

prefer detritus and decaying vegetation (The Global Invasive Species Database, 2006). We rated 

this element High.

_

Figure 2. Hardiness Zones potentially suitable for establishment by Lissachatina fulica 
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Ver. 5 May 7, 2012 21

Dispersal Potential. The distance travelled by L. fulica in one active night varies with the season 

and the age of the mollusk. The average distance travelled varied from 0.9 in October to 1.5 m. 

in June (India); and from 1.0 m in immature stages to 1.6 m in adult stages (Raut and Barke, 

2002).The most active individuals tracked in a study moved 500 meters in six months 

(Tomiyama and Nakane, 1993), and natural spread is estimated to be a few hundred meters per 

year (Lambert and Tillier, 1993).

Human assisted movement is the best way for long distance dispersal of quarantine pest. 

Lissachatina fulica could be introduced on: bulbs, tubers, corms, rhizomes, leaves, roots, stems 

(above ground), shoots, trunks, branches. All of them could carry eggs, and juveniles that could 

be visible to the naked eye (CABI, 2011). Other pathways for long distance movement include: 

conveyances (transport vehicles); all vehicles: land, sea, air. This pest has a high reproductive 

potential and the potential for natural spread appears to be limited, but deliberate movement by 

man has spread giant African snails to many areas of the world; thus, we rated the dispersal 

potential as High.

Economic Impact. Lissachatina fulica is a major agricultural pest, feeding on a variety of crops 

and causing significant economic losses. It is difficult to quantify the damage wrought by A. 

fulica to gardens and crops, but it is the most damaging land snail in the world (CABI, 2011). In 

Florida, L. fulica would have caused an estimated annual loss of $11 million in 1969 (or almost 

$54 million in 2002 dollars) if not controlled (PERAL, 2003). In India, L. fulica, caused severe 

damage to vegetable crops and rice paddies during 1946-47 when it appeared in epidemic 

proportions (Pallewatta et al., 2002), in The Global Invasive Species Database, 2006). 

Lissachatina fulica may also increase the spread of certain plant diseases via its feces, such as 

black pod disease caused by Phytophthora palmivora (Mead, 1961; Muniappan et al., 1986, in 

CABI, 2011). Many reports of widespread damage by L. fulica have been anecdotal. More 

recently, Civeyrel (1996) suggest that the lasting impact of L. fulica on agriculture may not be 

severe, and the human health risk is probably minor. The establishment of L. fulica in the United 

States could result in costs incurred not only for actual monetary damage to crops but also for 

control measures and surveys, and the potential loss of foreign markets for various agricultural 

commodities. The risk rating Host Range is High.

Environmental Impact. Introduction of an exotic can lead to loss of native populations and 

other impacts on communities; but measuring the economic value of a population of a rare 

species that is not used by humans is difficult (Civeyrel and Simberloff, 1996). Lissachatina

fulica consumes large volumes of native plants, modifies habitats and out-competes native snails 

(Moore, 2005, in The Global Invasive Species Database, 2006). Lissachatina fulica may also 

affect native ecosystems by altering the food chain, by providing an alternative food source for 

predators (Mead, 1961). This can have unfortunate consequences if the predator species is also 

invasive (CABI, 2011). Outbreaks in U.S. crops would likely trigger increased chemical control 

programs. Hence, we rated environmental impact for this pest to be High.

Mollusks: Deroceras laeve, Laevicaulis alte, Meghimatium bilineatum, M. pictum, Parmarion 

martensi, and Petalochlamys vesta

With the exception of Lissachatina fulica, we analyzed these mollusks species as a group 

because the lack of available scientific information to determine the risk element for each 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 22

individual species, the biology of the pest (they share similar characteristics such as having an 

inefficient means of locomotion), and been generalist feeders spending little time searching for 

specific foods (Speiser, 2001). Many mollusks are herbivorous and considered agricultural pests, 

but the majority of terrestrial gastropods feed on microorganisms associated with decaying 

vegetation (Speiser, 2001).

Climate/Host Interaction. Most of these mollusks have been reported from countries in East 

Asia: Cambodia, Vietnam, Malay Peninsula, Sumatra, Java, Borneo, Japan, Taiwan, Singapore, 

Samoa, and American Samoa (Hollingsworth et al., 2007; Noseworthy and Choi, 2007; Wu and 

Tsai, 2003). These correspond to Plant Hardiness Zones 9-11 (Fig. 1). The risk rating for the 

Climate-Host Interaction for these pests is Medium.

Host Range. Terrestrial snails are herbivorous. They feed on plant material (leaves, stems, soft 

bark, and fruits) and algae. The host range of these species covers several families, including 

Amryllidaceae, Araceae, Asteraceae, Euphorbiaceae, Fabaceae, Lauraceae, Malvaceae, 

Oleaceae, Orchidaceae, Passifloraceae, and Zingiberaceae (Hollingsworth et al., 2007). The risk 

rating for the Host Range for these pests is High.

Dispersal Potential. Some plant parts or material are not known to carry these pests in 

trade/transport, as follows: growing medium accompanying plants, flowers, inflorescences, 

cones, calyx, seedlings, micropropagated plants, true seeds, and wood (CABI, 2011). These pests 

can be transported for long distances, though, on conveyances (transport vehicles) and non-host 

plant material (e.g., , soil, gravel, and baggage) (CABI, 2011). Adults and juveniles move slowly

from one site to another, and the reproductive cycle is long and few eggs are produced (Lai, 

1984). Laevicaulis reproduce by parthenogenesis or out-crossing, although in some cases selfing 

only in isolation (Cowie et al., 2009). Primarily because of the likelihood of human-mediated 

transport, we rated the dispersal potential as Medium.

Economic Impact. Mollusk feeding reduces plant quality and productive leaf area, and some 

mollusks clip off succulent plant parts (Godan, 1983; Flinth, 1999). The introduction of the 

mollusk Bradybeana similaris into Louisiana and other states necessitated control treatments for 

this pest (Aguirre and Poss, 2000). Parmarion cf. martensi could become an important vector of 

Angiosiorus cantonensis in Hawaii (Hollingsworth et al., 2007). We found no reports about 

agricultural losses caused by Petalochlamys vesta, but this species could be as destructive as 

Pomacea canaliculata because of polyphagia and the huge population sizes ( Lee and Wu, 

2006). We rated this element High.

Environmental Impact. Nonindigenous species (NIS) had major impacts including degradation 

of wildlife habitat, decreased biological diversity, altered natural ecosystems, and negative 

effects on fishing and water sports (OTA, 1993). There is concern that because Taiwan is 

climactically similar to Florida, as well as California, in the continental United States and trust 

that nonindigenous species imported with orchids from Taiwan are more likely to become 

established in these areas. Biologists and ecologists caution that many poorly studied NIS have 

the potential of becoming agricultural pests, transmitting diseases, or displacing indigenous 

species (Ota, 1993).
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 23

The impact could be similar to that caused by L. fulica which could consume large volumes of 

native plants, modifies habitats and out-competes native snails (Moore, 2005, in The Global 

Invasive Species Database, 2006), affecting the native ecosystems by altering the food chain, by

providing an alternative food source for predators (Mead, 1961). Outbreaks in U.S. crops would 

likely trigger increased chemical control programs. The risk rating for the environmental impact 

of this pest is High.

Pectobacterium cypripedii

Climate/Host Interaction. Pectobacterium cypripedii was reported in the U. S. in the States of 

California, Florida, Idaho, California, New Mexico, and New York. These States represent at 

least 5 plant hardiness zones. Based on this distribution is estimated that P. cypripedii could 

establish in Puerto Rico and Hawaii. The risk rating for the Climate-Host Interaction for these 

pests for Hi and PR is High.

Host Range. Pectobacterium cypripedii has been reported affecting Cypipedium sp, and 

Phalaenopsis amabilis. This pest affects plants species within the Orchidaceae family and an 

occasionally infection on Carica papaya (Caricaceae) was reported by Leu (1980). We rated the 

Host Range for these pests as Medium.

Dispersal Potential. Movement in trade is likely to be by the transport of infected plants and/or 

compost (CABI, 2012). As many bacteria spread P. cypripedi can also be rain splashed. We rated 

High for the dispersal potential.

Economic Impact. There is no evidence that this pest has caused significant economic losses in the 

area where it has been established in the United States; therefore, the risk rating for the Economic 

Impact of this pest is Low.

Environmental Impact. This pest has the potential to affect orchidaceae plants listed as 

Endangered or Threatened in the Puerto Rico and Hawaii (Cranichis ricartii, Lepanthes 

eltoroensis, and Platanthera holochila) (50 CFR§17.12, 2005), but we found no evidence of 

significant impacts in areas in the continental United States where this pest is already 

established. The risk rating for the Environmental Impact of this pest is Medium

Scirtothrips dorsalis

Climate/Host Interaction. This species is distributed over several countries:, Bangladesh, 

Barbados Brunei, China, , Indonesia, India, Israel, Jamaica, Ivory Coast, Japan, Kenya, Korea 

Republic, Venezuela, Vietnam , Papua New Guinea, Solomon Island, South Africa in the US 

(HI, FL, TX, GA) (CABI, 2011, EPPO, 1997a). This species is widely distributed over several 

subtropical and tropical countries (EPPO, 1997a) corresponding to Plant Hardiness Zones 7 - 11 

(USDA-APHIS-PPQ-CPHST, 2005). The risk rating for the Climate-Host Interaction for these 

pests is High.

Host Range. This thrips is mainly a foliage feeder; it does not feed on flower pollen (Edwards, 

2010). The host range of S. dorsalis includes over 40 plant families. Plant species attacked by S. 

dorsalis include Odontonema strictum (Acanthaceae); Actinidia deliciosa (Actinidiaceae); Ilex 

crenata , I. integra (Aquifoliaceae); Alternanthera sessilis, Amaranthus spp., A. blitum,

(Amaranthaceae); Anacardium occidentale, Mangifera indica (Anacardiaceae); Calotropis 
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Ver. 5 May 7, 2012 24

gigantea (Apocinaceae); Schefflera arboricola (Araliaceae); Chrysanthemum x morifolium, 

Dahlia pinnata, Imorphotheca aurantiaca, Helianthus annuus, Sonchus asper (Asteraceae); 

Viburnum awabuki, V. suspensum (Caprifoliaceae); Euonymus japonicus (Celastraceae); Beta 

vulgaris (Chenopodiaceae); Conocarpus erectus, Laguncularia racemosa (Combretaceae); 

Ipomoea batatas (Convolvulaceae); Citrullus lanatus, Cucumis melo, C. sativus, Cucurbita pepo

(Cucurbitaceae); Diospyros kaki (Ebenaceae); Pieris japonica, Rhododendron sp. (Ericaceae); 

Hevea brasiliensis, Hevea sp., Ricinus communis (Euphorbiaceae); Acacia arabica, A. brownie, 

Acacia spp. A. auriculiformis,Arachis hypogaea, Brownea spp., Dolichos lablab, Glycine max, 

Melanoxylum sp., Melilotus indica, Mimosa pudica, Phaseolus vulgaris, Saraca minor, Saraca 

spp., Tamarindus indica, Vigna radiata (Fabaceae); Castanea crenata, Quercus glauca, Q. 

virginiana, Saraca indica (Fagaceae); Ginkgo biloba (Ginkgoaceae); Distylium racemosum

(Hamamelidaceae); Hydrangea spp. (Hydrangeaceae); Laurus nobilis (Lauracea), Lamium 

barbatum (Lamiaceae); Allium cepa, A. sativum, Asparagus officinalis (Liliaceae); Cuphea 

hyssopifolia (Lythraceae); Gossypium herbaceu, G.hirsutum (Malvaceae); Ficus carica, F. 

elastic, Morus sp. (Moraceae); Musa sp. (Musaceae); Syzygium malaccense, S. samarangense

(Myrtaceae); Nelumbo lutea, N. nucifera (Nelumbonaceae); Jasminum multiflorum, Ligustrum 

japonicum, Osmanthus heterophyllus (Oleaceae); Passiflora edulis (Passifloraceae); Eurya 

japonica (Pentaphylacaceae); Sauropus androgynus (Phyllanthaceae); Pittosporum tobira

(Pittosporaceae); Plumbago auriculata (Plumbaginaceae); Zea mays (Poaceae); Coccoloba 

uvifera (Polygonaceae); Podocarpus macrophyllus (Podocarpaceae); Fagopyrum esculentum

(Polygonaceae); Portulaca oleracea (Portulacaceae); Punica granatum (Punicaceae); Zizyphus

mauritiana (Rhamnaceae); Fragaria x ananassa, F. chiloensis, Photinia glabra, Prunus sp., P. 

mume, P. persica, P. salicina, Pyracantha angustifolia, Pyrus spp., Rhaphiolepis indica, R. 

umbellata Rosa spp., Rubus spp. (Rosaceae); Gardenia jasminoides (Rubiaceae) Citrus 

aurantiifolia, C. maxima, C. sinensis, C. unshiu, Murraya paniculata, Zanthoxylum piperitum

(Rutaceae); Populus deltoids (Salicaceae); Acer sp., Dimocarpus longan, Litchi chinensis, 

Nephelium lappaceum (Sapindaceae); Capsicum annuum, C. frutescens, Lycopersicon 

esculentum, Nicotiana tabacum, Solanum melongena, . (Solanaceae), Theobroma cacao

(Sterculiaceae); and Camellia japonica, C. sasanqua, C. sinensis Theaceae Ampelopsis 

brevipedunculata, Cayratia japonica, Vitis pteroclada V. vinifera (Vitaceae) (CABI, 2011; 

EPPO, 1997a; Edwards et al., 2010). The risk rating for the Host Range for these pests is High.

Dispersal Potential. Reproduction potential: Fecundity depends on host plant quality. Duration 

of each life stage (Amin and Palmer 1985): eggs 6-8 days, larval stages 6-7 days, pupal stages 2-

3 days, adults up to 22 days with an average of 11 days. Reproduction is both sexually and 

parthenogenically (Edwards et al., 2010). In castor, the total number of eggs laid by a female 

ranges from 40-66; in chilies, a female lays 2-4 eggs per day for about 32 days (CABI, 2011), 

The thrips female oviposit 60 to 200 eggs in her lifetime (Ludwing et al., 2007). The life-cycle is 

completed in 13-20 days, depending on host plant and season. Dispersal: Records from USDA 

PestID database indicate 90 interceptions of S. dorsalis, including some on fresh fruit (13), 

flowers (33), foliage (16) and undetermined (24) (PestID, 2010). Because this pest has a high 

reproductive potential and is able to fly for long distance the risk rating for the dispersal potential 

is High.

Economic Impact. Scirtothrips dorsalis is polyphagous with a very large host range, 

Scirtothrips dorsalis has the potential to cause significant economic damage if it were to 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 25

establish in the U.S.( Seal et al., 2010) Scirtothrips dorsalis has been reported as a serious pest of 

a diverse variety of commodities in several countries. Scirtothrips dorsalis has been reported as a 

serious pest on cotton in Ivory Coast, India, and Pakistan, citrus in Japan (Masui, 2008; Longo, 

1986 ) and Taiwan, peanuts in India, peppers and chilies in India, mangos in Taiwan, litchis in 

China, roses in India and Taiwan, Hevea brasiliensis in Malaysia, lotus in Taiwan, (USDAAPHIS-PPQ-CPHST, 2005), strawberries in Queensland and Australia, tea in Taiwan, soybeans 

in Indonesia, (Edwards et al., 2010), capsicum and groundnuts in India, grapevine (although 

Scirtothrips dorsalis may not breed on grapevines) and tea in Japan, (GPDD 2006), and chili 

peppers in Sri Lanka (Schall 1995). Scirtothrips dorsalis has also been reported to cause damage 

in onions, tomatoes, tamarind, cashews, and castor beans (Edwards et al., 2010). The majority of 

the above listed commodities occur in the U.S. and in fact 34 major commodity hosts exist in 

areas climatically suitable for establishment (USDA-APHIS-PPQ-CPHST, 2005). Therefore, the 

risk rating for the Economic Impact of this pest is High.

Environmental Impact. The following Endangered or Threatened species could be attacked: 

Allium munzii (CA), Amaranthus pumilus (DE, MA, MD, NC, NJ, NY, RI, SC, VA), Cucurbita 

okeechobeensis ssp. okeechobeensis (FL) (50 CFR§17.12, 2005). Additional chemical control 

would likely be implemented since it is often used against this pest (CABI, 2011; Seal et al., 

2006; Reddy et al., 2005). The risk rating for the Environmental Impact of this pest is High.

Spodoptera litura

Climate/Host Interaction. This species is distributed over several countries: Afghanistan, 

Bangladesh, Brunei, Cambodia, China, Christmas Island, Hong Kong, Indonesia, India, Iran, 

Japan, Korea Democratic People's Republic, Korea Republic, Lao, Maldives, Malaysia, 

Myanmar, Nepal, Oman, Pakistan, Philippines, Singapore, Sri Lanka, Taiwan, Thailand, Viet 

Nam, American Samoa, Australia (Northern Territory, New South Wales, Queensland, Western 

Australia), Cocos Islands, Cook Islands, Fiji, French Polynesia, Guam, Kiribati, Marshall 

Islands, New Caledonia, Niue, Norfolk Island, Northern Mariana Islands, Micronesia, Palau, 

Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu, Vanuatu, Wallis and Futuna 

Islands; Russia, and in the US (Hawaii) (CABI, 2011). This species is widely distributed over 

several subtropical and tropical countries (EPPO, 1997c) corresponding to Plant Hardiness Zones 

7 - 11 (Fig. 3). (Magarey et al., 2008). The risk rating for the Climate-Host Interaction for these 

pests is High.

Host Range. The host range of S. litura includes over 40 plant families. Plant species attacked 

by S. litura in the tropics are Oncidium sp. (TARI, 2009), Dendrobium sp. (Orchidaceae) 

(Kumari and Lyla, 2001; Weaver, 2003), Colocasia esculenta (Araceae), Brassica sp. 

(Brassicaceae), Ipomea batatas (Convolvulaceae), Cucumis sp. (Cucurbitaceae), Ricinus sp. 

(Euphobiaceae), Arachis sp., Glycine sp., Leucaena leucocephala, Medicago sativa, Phaseolus

sp., Vigna sp (Fabaceae), Linum sp (Linaceae), Corchorus sp., Gossypium sp. (Malvaceae), Zea 

mays, Oryza sp. (Poaceae), Capsicum sp., Nicotiana tabaccum, Solanum melongena, S. 

tuberosum (Solanaceae), and Camelia sp. (Theaceae) (CABI, 2011; EPPO, 1997c). The risk 

rating for the Host Range for these pests is High.

Dispersal Potential. The moths can fly about 2 km in 4 hours overnight, facilitating dispersion 

and oviposition on different hosts (CABI, 2011; EPPO, 1997c). In international trade, eggs or 
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Ver. 5 May 7, 2012 26

larvae may be present on planting material, cut flowers, or vegetables. Fecundity may be as high 

as 5,900 eggs per female (Chu and Ou-Yang, 1991) with up to 12 generations annually (CABI, 

2011; EPPO, 1997c). Because this pest has a high reproductive potential and is able to fly for 

long distance the risk rating for the dispersal potential is High.

Economic Impact. S. litura is an extremely serious pest, for example, in India, soybean yield 

loss was estimated at over 40 percent due to this pest and up to 50 percent on tobacco. In 

Japanese greenhouses, a 10 percent yield loss in peppers was found (EPPO, 1997c). Similar 

losses may be expected on crops in the PRA area ( EPPO, 1997c). In addition, its establishment 

in the United States may lead to the loss of export markets. Therefore, the risk rating for the 

Economic Impact of this pest is High.

Figure 3. Plant Hardiness Zones potentially suitable for establishment by Spodoptera litura and 

Scirtothrips dorsalis

Environmental Impact. Hosts include endangered species in the genera Trifolium (T. amoenum, 

T. stoloniferum, T. trichocalyx) and Phaseolus (P. supinus) (50 CFR§17.12, 2005). Outbreaks in 

crops in the PRA area would likely trigger increased chemical control programs similar to those 

now in effect for other caterpillars. The risk rating for the Environmental Impact of this pest is 

High.
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Tetranychus kanzawai 

Climate/Host Interaction. Tetranychus kanzawai was reported in the US in the States of 

California, and New York (Migeon and Dorkeld, 2006). These states represent at least 5U.S. 

plant hardiness zones. Based on this distribution, it is estimated that T. kanzawai could establish 

permanent in Puerto Rico and Hawaii. One or more of its potential hosts occur in these zones 

(Magarey et al., 2008). The risk rating for the Climate-Host Interaction for these pests is High 

Host Range. Tetranychus kanzawai is a polyphagous pest that affects more than 160 plant species 

in at least 60 families (Migeon and Dorkeld, 2006); therefore the risk rating for this pests is High.

Dispersal Potential. The biology of T. kanzawai species was recently studied in detail by Kim 

(1993) in Korea. Under constant temperatures of 15, 20, 25 and 30°C, the egg periods averaged 

15.1, 8.9, 4.4 and 2.3 days, respectively, the larval periods 6.4, 3.5, 1.9 and 1.2 days, 

protonymphal periods 5.6, 2.8, 1.7 and 1.0 days, and deutonymphal periods 7.5, 4.0, 2.1 and 1.3 

days. The corresponding adult female lifespans were 33.3, 16.8, 15.5 and 13.4 days, and average 

numbers of eggs laid per female 37.5, 59.4, 100.6 and 103.3. Similar biological studies have 

been reported by Tsai (1989) in Taiwan and in China Cao et al., 1998. Female of T. kanzawai 

can mature and deposit up to 3,000 eggs during their life; generation times range from 13-33 

days, depending on the temperature and host plant (Kim et al., 1993)so several generations per 

year are possible. Because this pest has a high reproductive potential and is able to disperse long 

distances in contaminated plant material the risk rating for the dispersal potential is High

Economic Impact. T. kanzawai is a major pest of tea, egg plants, and other crops in Japan and 

southern China. Wang (1981) reported that it caused serious damage to cherries in China. This 

species is an important pest of egg plants in Taiwan (Ho and Chen, 1992 ). It was recently 

recorded on cassava in Congo (Gutierrez and Bonato, 1994) and in the Philippines (Villacarlos 

and Vasquez, 1988). The cost of chemical control of T. kanzawai on strawberries in Taiwan 

exceeds US$233/ha (Chang and Huang, 1995). Its establishment in the Puerto Rico and Hawaii 

could result in the loss of foreign markets for various agricultural commodities, but there is no 

evidence of significant impact in areas present in the continental U. S., therefore, we rated Medium

for the Economic Impact. 

Environmental Impact. This pest has the potential to attack plants listed as endangered or 

threatened in the United States. Species that could potentially be affected in the PRA area (HI) are 

Canavalia spp.(2 species), Euphorbia sp, Gardenia spp (2 species), Hibiscus spp. (4 species) 

Solanum spp. (1 species), Vicia spp., Vigna spp., Viola spp.., Zanthophyllum spp.(50 CFR§17.12, 

2005). Its introduction could initiate control programs in areas of the United States to which it 

was newly introduced because it is a major pest of numerous economic crops, but there is no 

evidence of significant impacts in areas in the continental United States where this pest is already 

established. The risk rating for the Environmental Impact of this pest is Medium.

Thrips palmi 

Climate/Host Interaction. Thrips palmi is subtropical to tropical in distribution; populations in 

temperate climates are able to overwinter in greenhouses or other artificial situations since it cannot 

survive subzero temperatures for more than a few days (Lewis, 1997; Capinera, 2010). This thrips 

occurs in Asia, (Bangladesh, Brunei, China, India, Indonesia, Japan, Korea DPR, Korea republic, 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 28

Malaysia, Pakistan, Philippines, Singapore, Sri Lanka, Taiwan, Thailand, Turkey; Africa (Ivory

coast, Mauritius, Nigeria, Reunion, and Sudan), north America (Bermuda, Mexico, US –FL and 

HI), Central America (Antigua, Bahamas, Barbados, Cuba, Dominica, Dominican Republic, Haiti, 

Jamaica, Martinique, Puerto Rico and Trinidad and Tobago) South America (Brazil, Colombia, 

Guyana., Suriname, Venezuela); parts of the tropical Pacific (American Samoa, Australia, French 

Polynesia, Samoa, and Africa, and, recently, in the Caribbean and northern South America. United 

States populations are restricted to American Samoa, southern Florida, Guam, Hawaii and Puerto 

Rico (CABI, 2011, Capinera, 2010). Based on this distribution, it is estimated that T. palmi could 

establish permanent outside populations in the United States in U.S. Plant Hardiness Zones 9-11 

(Figure 1). One or more of its potential hosts occur in these zones (Magarey et al., 2008). The risk 

rating for the Climate-Host Interaction for these pests is Medium

Host Range. Thrips palmi is a polyphagous pest that attacks plants in several families. Among 

primary hosts are species of Actinidia chinensis, A. deliciosa (Acitnidiaceae); Amaranthus 

spinosus, A. tricolor, A. viridis (Amaranthaceae); Mangifera indica (Anacardiaceae); Ageratum 

spp., A. conyzoides, Chrysanthemun sp., Helianthus annuus, Lactuca sativa (Asteraceae), Cucumis 

melo, C. sativus, Cucurbita moschata, C. pepo (Cucurbitaceae); Allium cepa (Liliaceae), Arachis 

hypogaea, Glycine max, Phaseolus vulgaris, Vigna ungiculat (Fabaceae), Persea americana

(Lauraceae); Gossypium sp., Abelmoschus esculentus (Malvaceae); Oryza sativa (Poaceae), 

Sesamum indicum (Pedaliaceae); Citrus spp., C. medica, C. sinensis (Rutaceae), Capsicum spp., C.

annuum, Nicotiana tabacum, Solanum lycopersicum, S. melongena, and S. tuberosum (Solanaceae) 

(CABI, 2011). The risk ratings for these pests is High.

Dispersal Potential. Female T. palmi can mature and deposit up to 204 eggs during their life; 

generation times range from 11.5-20 days, depending on the temperature and host plant (CABI, 

2011; Capinera, 2001) . Several generations per year are possible. Originally restricted to south 

and Southeast Asia, over the past 25 years, T. palmi has rapidly spread to Australia, Africa, and the 

Western Hemisphere (CABI, 2011). Bournier, (1986) suggested that rapid, long-distance dispersal 

is facilitated by wind and aircraft transport of infested plant materials. Adults are capable of flight, 

and their small size and fringed wings allow long distance dispersal via wind Lewis, 1997. The 

species has been intercepted over 8100 times at U.S. ports during the last 25 years (PestID, 2010); 

thus, this pest could be easily moved on plant material. . Because this pest has a high reproductive 

potential and is able to fly for long distance the risk rating for the dispersal potential is High.

Economic Impact. Thrips palmi is a serious pest of cucurbits and eggplant. Losses of 50-90% in 

these crops have been reported (CABI, 2007). On cucumber, feeding stunts plants, causing 

premature bud and fruit drop, and deforming fruits that survive; infestations can be as low as one 

thrips per leaf, which results in fewer tendrils and leaves, and dead plants (Lewis, 1997). The 

species is a vector of tomato spotted wilt tospovirus (CABI, 2011). It is difficult to control 

chemically, requiring repeated applications of insecticides to achieve acceptable levels of control 

(Sakimura et al., 1986). Its establishment in the United States could result in the loss of foreign 

markets for various agricultural commodities.. Therefore, the risk rating for the Economic Impact 

of this pest is High.

Environmental Impact. This pest has the potential to attack plants listed as Endangered or 

Threatened in the United States (e.g., Allium munzii (CA), Cucurbita okeechobeensis ssp. 

okeechobeensis (FL), Helianthus spp. three species in AL, KY, NC, NM, SC, TN, TX.) (50 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 29

CFR§17.12, 2005). Its introduction would undoubtedly initiate control programs in areas of the 

United States to which it was newly introduced because it is a major pest of numerous economic 

crops (e.g., beans, peppers and tomatoes). Similar programs have been considered in other 

countries (e.g., Japan) (Hirose et al., 1993).) Outbreaks in crops in the PRA area would likely 

trigger increased chemical control programs similar to those now in effect for other caterpillars. 

The risk rating for the Environmental Impact of this pest is High

Table 5. Summary of the risk ratings for the Consequences of Introduction 

Pest Climate/Host 

interaction

Host 

range

Dispersal 

potential

Economic 

impact

Environmental 

impact

Cumulative 

risk ratinga

Amsacta lactinea Med (2) High (3) Med (2) High(3) High (3) High (13)

Bipolaris zizaniae Med (2) Med (2) High (1) Low (1) Low (1) Med (9)

Lissachatina fulica Low (1) High (3) High (3) High (3) High (3) High (13)

Mollusks: Deroceras laeve, 

Laevicaulis alte, Meghimatium 

bilineata, M. pictum, Parmarion 

martensi, Petalochlamys vesta

Med (2) High (3) Med (2) High (3) High (3) High (13)

Pectobacterium cypripedii High (3) Med (2) High (3) Low (1) Med (2) Med (11)

Scirtothrips dorsalis High (3) High (3) High (3) High (3) High (3) High (15)

Spodoptera litura High (3) High (3) High (3) High (3) High (3) High (15)

Tetranychus kanzawai High (3) High (3) High (3) Med (2) Med (2) High (13)

Thrips palmi High (2) High (3) High (3) High (3) High (3) High (14)

a Low = 5-8 points, Medium = 9-12, and High = 13-15.

2.5.2. Likelihood of Introduction

We assess the Likelihood of Introduction for a pest based on six factors (PPQ, 2000). One is the 

amount of commodity likely to be imported. The other five are based on the biology of the pest 

in interaction with the commodity, as follows: the effectiveness of post-harvest treatments, pest 

survival during shipping, pest detection at ports-of-entry, the pest being moved to a suitable 

environment, and the pest coming into contact with suitable hosts. These represent a series of 

independent events that must all take place before a pest outbreak occurs. The value for the 

Likelihood of Introduction is the sum of these six ratings, which we summarized below (Table 

6). 

Quantity of commodity imported annually. This rating is based on the amount reported by the 

country of proposed export converted into standard units of 40-foot long shipping containers. 

Permission to import into the United States is likely to be linked with an increase in production 

in the future and subsequent increases in the volumes of imports. 

Cut flowers of Oncidium spp. is the major product for export but live plants and seedlings are 

also exported. The United States is the leading market for live Oncidium sp. plants, at about 

24,000 kg (BAPHIQ, 2007). No more than ten containers per year have ever been exported or 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 30

are expected to be exported from Taiwan into the United States. Given that, we rated this subelement Low for all pests. 

Availability of post-harvest treatments. For this sub-element, post-harvest treatment refers to 

any manipulation, handling, or specific phytosanitary treatment to which the commodity is 

subjected. Examples of post-harvest treatment include culling, washing, chemical treatment, cold 

storage, etc. No specific postharvest treatments have been proposed for this commodity, so we 

rated this sub-element High. 

Survive shipment. To obtain optimum success in propagation and cultivation, live plant material 

should be transported as rapidly as possible, which usually means to be shipped via airfreight, 

which makes its transport period short in duration (CITES., 2010). The conditions are likely to 

be moderate temperatures and humidity, which is unlikely to adversely affect any of the 

quarantine pest populations. For example, larval stages of Spodoptera sp. are often intercepted, 

indicating they routinely survive shipment (PestID, 2010). Finally, the conditions required for 

plant survival during shipment are very unlikely to inhibit the growth of any pest that is likely to 

follow the pathway. For these reasons, we rated this sub-element High for all the pests. 

Not detected at the port-of-entry. 

Amsacta lactinea. Damage caused by early instars of Amsacta lactinea is easily detected as 

chlorophyll-free, whitish leaves, with the network of veins intact. Heavy foliar damage indicates 

the presence of late-instar larvae which, being reddish brown and possessing tufts of long hair, 

are easily spotted against the green background of the crop (CABI, 2011). Minute pellets of 

larval excreta 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 makes their detection easier 

(CABI, 2011). Thus, we rated this sub-element Low for this pest.

Bipolaris zizaniae. Standard visual inspection techniques are likely to detect spots on petals of 

Oncidium orchids caused by B. zizaniae. Infection studies of rice cultivars with various isolates of 

Helminthosporium oryzae (a closely related species to B. zizaniae) indicated that this pathogen 

does not have any type of dormancy, and that inoculated plants readily express symptoms 

(Vidhyasekaran, 1991). We rated this element Low for B. zizaniae.

Pectobacterium cypripedii. This pathogen causes brown rot on orchids with fleshy leaves. Initial 

symptoms are small, water-soaked lesions which enlarge to become brown, greasy-looking, 

slightly sunken areas (CABI, 2012). These lesions are easy to detected during inspection, 

therefore we rated this sub-element Low for this pathogen

Spodoptera litura. The larvae of S. litura can be up to 45 mm in length and are typically found 

on plant surfaces (CABI, 2011; Matsuura and Naito, 1992; EPPO, 1997c; Pogue, 2002). Eggs 

hidden between leaves, in media, or within flowers are more difficult to detect (Pogue, 2002). 

We rated this sub-element Medium for S. litura.

Scirtothrips dorsalis, Tetranychus kanzawai, and Thrips palmi. Thrips are not easily detectable 

because of their small size, so quarantine procedures are difficult to manage. In addition the plant 

characteristic allow for the presence of places where these pests could hide (pseudobulb scales 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 31

and leaf sheath). Thrips leave numerous scars and deformities. We rated this sub-element High

for these pests.

Deroceras laeve, L. fulica, L. alte, M. bilineatum, M. pictum, P. martensi, and P. vesta. These 

mollusks cause lesions on plants that may be detected by visual inspection. Standard inspection 

techniques are highly likely to detect larger mature and juvenile forms of mollusks on plants 

(e.g., Acusta tourranensis; Robinson, 2002). Small eggs in soil are highly likely to escape 

detection. We rated this sub-element High for these pests.

Moved to a suitable habitat. Amsacta lactinea, Pectobacterium cypripedii, Spodoptera litura , 

Scirtothrips dorsalis, Tetranychus kanzawai , and Thrips palmi have tropical and subtropical 

distributions, and those areas are limited in the continental United States to the South and the 

West Coast. These comprise 10-12 percent of the total land area of the continental United States. 

Imported plants could also be placed in warm, indoor sites (such as greenhouses or shops) where 

the pests may proliferate. For these reasons, we rated this sub-element High for these pests.

Bipolaris zizaniae is similar to the above pests in distribution, but has a much more limited host 

range. For that reason, we rated it Medium.

Mollusks. Lissachatina fulica and the other mollusks species shipped to temperate United States 

ports in winter, spring, or fall are not likely to find suitable outdoor habitats, but if moved into 

warm, indoor sites (such as greenhouses or shops) the pests may proliferate (CABI, 2011; 

Godan, 1983; Lai, 1984; Flinth, 1999 ). Pests on plants shipped to subtropical ports are more 

likely to find a suitable habitat. For these reasons, we rated this sub-element High for these pests.

Contact with host material. All of the pests are highly likely to contact host material because 

the infested orchids are likely to be grown near other orchids indoors or in greenhouses. 

Additionally, all of the pests were rated High for host range, above, so they are more likely to 

find acceptable host material. For these reasons, we rated this sub-element High for all pests, but 

B. zizaniae.

A series of events have to occur for the pest to contact suitable host material and establish a 

colony. First, infected plant material must produce inoculum that will be disseminated to other 

susceptible plants (there are no records that infected Oncidium petals produce significant 

amounts of inoculum to initiate infection of petals on other Oncidium orchids in blooming stage, 

instead, the source of inoculum for the disease was considered to come from Bipolaris-infected 

water bamboo (Zizania latifolia) nearby. Second, the natural host of this pathogen is not present 

in the US; therefore lacking appropriate conditions for establishment, we rated it as Low risk for 

this sub-element
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Table 6. Summary of the risk ratings for the Likelihood of Introduction. The ratings for all pests 

for ‘Quantity imported annually’ were Low.a

Pest Survive postharvest 

treatment

Survive 

shipment

Not detected 

at port-ofentry

Moved to 

a suitable 

habitat

Find 

suitable 

hosts

Cumulative 

risk ratingb

Amsacta lactinea High (3) High (3) Low (1) High (3) High (3) Med (14)

Bipolaris zizaniae High (3) High (3) Low (2) Med(1) Low (1) Med(11)

Lissachatina fulica High (3) High (3) High (3) High (3) High (3) High(16)

Mollusks: Deroceras 

laeve, Laevicaulis alte,

Meghimatium bilineata, 

M. pictum, Parmarion 

martensi, Petalochlamys 

vesta

High (3) High (3) High (3) High (3) High (3) High(16)

Pectobacterium 

cypripedii

High (3) High (3) Low (1) High (3) High (3) Med (14)

Scirtothrips dorsalis High (3) High (3) High (3) High (3) High (3) High (16)

Spodoptera litura High (3) High (3) Med (2) High (3) High (3) High (15)

Tetranychus kanzawai High (3) High (3) Med (2) High (3) High (3) High (15)

Thrips palmi High (3) High (3) High (3) High (3) High (3) High (16)

a This rating adds 1 point to the sum of each row for all pests.

b Low = 6-9 points, Medium = 10-14 points, and High = 15-18 points.

2.6. Conclusion

Summing the values for Consequences of Introduction and Likelihood of Introduction gives an 

estimate of the Pest Risk Potential (Table 7). For pests with a High Pest Risk Potential, specific 

phytosanitary measures (in addition to port of entry inspection) are recommended to ensure 

phytosanitary security.

Table 7. Pest Risk Potentials for quarantine pests of Oncidium spp. from Taiwan.

Pest Consequences 

of Introduction

Likelihood of 

Introduction

Pest risk 

potentiala

Amsacta lactinea High (13) High (16) High (29)

Bipolaris zizaniae Med (9) Med (11) Medium (20)

Lissachatina fulica High (13) High (16) High (29)

Mollusks: Deroceras laeve, Laevicaulis alte,

Meghimatium bilineata, M. pictum, Parmarion 

martensi, Petalochlamys vesta

High (13) High (16) High (29)

Pectobacterium cypripedii Med (11) Med (14) Medium (25)

Scirtothrips dorsalis High (15) High (16) High (31)

Spodoptera litura High (15) High (15) High (30)

Tetranychus kanzawai High (13) High (15) High (28)

Thrips palmi High (14) (High 16) High (30)

a Low (11-18 points), Medium (19-26 points), and High (27-33 points)
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Ver. 5 May 7, 2012 33

3. Risk Management

3.1. Introduction

This section describes the phytosanitary measures required if Oncidium spp. plants in approved 

growing media are imported into the United States from Taiwan. The pest risks identified above 

are the baseline risk associated with the unmitigated importation of Oncidium spp. orchids from 

Taiwan in APHIS-approved growing media. The proposed importation, if approved, would be 

regulated by the existing regulations for plants in growing media (7 CFR § 319.37-8, 2009a). 

The mitigations described therein comprise a systems approach designed to establish and 

maintain a pest-free production environment and ensure the use of pest-free parent plants. These 

mitigations, when applied to this importation, effectively reduce the risk of these pests following 

the pathway on Oncidium in growing media from Taiwan.

3.2. Systems Approaches

The Plant Protection Act of 2000 (7 U.S.C. § 7701-7786, 2000) defines 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.” This is similar to the 

international standards definition, “The integration of different pest risk management measures, 

at least two of which act independently, and which cumulatively achieve the desired level of 

phytosanitary protection” (IPPC, 2007: ISPM #5). Systems approaches are employed as an 

alternative to the use of single measures that achieve an appropriate level of phytosanitary

protection when a single phytosanitary measure is nonexistent, infeasible, or undesirable. The 

combinations of specific mitigation measures that provide overlapping or sequential safeguards 

are distinctly different from single mitigation methodologies such as fumigation or inspection. 

Systems approaches vary in complexity but they all require the integrating multiple measures 

with a cumulative effect and are often tailored to specific commodity-pest-origin combinations. 

Options for specific measures may be selected from a range of pre-harvest and post-harvest 

measures, e.g., surveys, inspections, sanitation, chemical treatment. Options may include 

mitigation measures to compensate for uncertainty. PPQ uses systems approaches for the 

importation of many commodities including Unshu oranges from Japan (7 CFR § 319. 28, 2008), 

tomatoes from Spain, France, Morocco, and Western Sahara), and peppers from Israel (7 CFR § 

319.56, 2009). These programs have performed successfully for many years.

The three main categories of mitigation measures that would be specifically required by 7 CFR § 

319.37-8(e) for Oncidium plants in growing media from Taiwan are as follows:

 pest-free propagative material

 pest-exclusionary greenhouses

 inspection

Ensuring pest-free propagative material requires monitoring and testing of mother stock and 

descendant plants (Agrios, 1997; BAPHIQ, 2002; Jarvis, 1992). Pest-exclusionary greenhouses 

employ treatments, good sanitation (e.g., surface disinfestation of tools and plant 

materials).(Agrios, 1997; Jarvis, 1992; Baker and Baker, 2006; Kahn and Mathur, 1999), clean 

water sources (Jarvis, 1992; Kahn and Mathur, 1999; Van der Plank, 1963), and use of approved 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 34

growing media. Pathogens are typically not present in APHIS-approved growing media (Palm, 

1994; Santacroce, 1991). 

While not specifically required under 7 CFR§319.37-8(e), standard industry practices help to 

further ensure that the pests of concern do not follow the pathway. These include in vitro or 

aseptic vegetative propagation (Hsieh, n.d.; Pearson et al., 1991) to ensure pest free seedlings; 

and chemical treatments designed to reduce or eliminate mealybugs (Cory and Highland, 1959), 

viruses (Gara et al., 1997; Inouye and Gara, 1996; Wey et al., 2001) and fungi (Baker and Baker, 

2006; McCain et al., 1973). Other cultural practices enhance plant vigor so that pests are less 

likely to infest plants (Smith and Neal, 1998, proper lighting (Konow and Wang, 20001), 

temperature (Baker and Baker, 2006; Wey, 2002), aeration and watering (Frank, 1998; Miller, 

1990), and nutrition (Wang, 1998; Wang and Gregg, 1994). 

3.3. General Program Requirements for Plants in Growing Media

Approved growing media include baked expanded clay pellets, coal cinder, coir, cork, glass 

wool, organic and inorganic fibers, peat, perlite, phenol formaldehyde, plastic particles, 

polyethylene, polymer stabilized starch , polystyrene, polyurethane, rock wool, sphagnum moss, 

ureaformaldehyde, stockosorb superabsorbent polymer, vermiculite, volcanic rock, or zeolite, or 

any combination of these media (7 CFR § 319.37-8, 2009b). Growing media must not have been 

previously used.

Risk mitigation measures for Oncidium plants from Taiwan are drawn from the general risk 

mitigation program requirements for certain plants in growing media (7 CFR§ 319.37-8(e), 

2010). That regulation states:

(1) Plants must be established in approved unused growing media.

(2) Articles must be grown in compliance with a written agreement for enforcement of this 

section signed by the plant protection service of the country of the country of origin and Plant 

protection and quarantine APHIS. The plants must be developed from mother stock which has 

been inspected no more than sixty days before establishment of the plants. The inspection will be 

performed by an APHIS inspector or an inspector of the plant protection service of the country of 

origin.

(3) The plants must be grown in compliance with a written agreement between the grower 

and the plant protection service of the country of origin. The grower must allow access to his 

facility to make sure he is complying with the regulations.

(4) “Grown solely in a greenhouse in which sanitary procedures are adequate to exclude 

plant pests and diseases are always employed, including cleaning and disinfection of floors, 

benches, and tools, and the application of measures to protect against any injurious plant 

diseases, and injurious insect pests, and other plant pests” (7 CFR § 319.37–8(e)(2)(ii)). All 

entryways must be equipped with automatic closing doors.

(5) Rooted and grown in an active foliar state for at least four consecutive months before 

export. 

(6) Grown from seeds germinated in the greenhouse or descended from a mother plant that 

was grown for at least nine months in the exporting country. If the mother plant was imported 

into the exporting country then it must be grown for at least twelve months prior to establishment 
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 35

of the descendent plants or treated at the time of importation into the exporting country with a 

treatment for pests of the plant prescribed by the plant protection service of the exporting country

and then grown for nine months prior to establishment of descendent plants.

(7) Watered only with rainwater that has been boiled or pasteurized, with clean well water 

or with potable water.

(8) Rooted and grown in approved growing media on benches supported by legs and raised 

at least 46cm off the floor.

(9) Stored and packed only in areas free of soil earth and plant pest.

(10) Inspected in the greenhouse and found free of evidence of plant pests and diseases by an 

APHIS inspector or an inspector of the plant protection service of the country of origin.

3.4. Evidence for the Effective Removal of Pests of Concern from the Pathway 

Measure Evidence Pest Reference 

1 Approved growing media is not a good 

pathway for snail movement. 

Mollusks

(Laevicaulis alte, 

Lissahatina fulica , 

Meghimatium 

bilineata, M. pictum, 

Parmarion martensi, 

Petalochlamys vesta)

Hollingsworth 

and Sewake, 

2002

2, 5, 10 All mother stock must be examined no 

more than sixty days before establishment 

and plants must be actively growing stage 

for four months. In addition, the orchids 

must be inspected in the greenhouse and 

found free of evidence of quarantine pest 

by an APHIS inspector or an inspector of 

the plant protection service of the country

of origin. Snails are detectable by slime 

trails, chewed leaves and excrement. Since 

standard inspection techniques are highly 

likely to detect larger mature and juvenile 

forms of mollusks, this would allow snails 

to be found either before they move into 

the greenhouse or during required 

inspections. 

Amsacta lactinea, 

Mollusks, 

Scirtothrips dorsalis, 

Spodoptera litura, 

Thrips palmi.

Robinson, 

2002; 

Santacroce, 

1991; CABI, 

2011

4, 7, 8, 9 Plants will be grown solely in greenhouses 

with sanitary procedures adequate to 

exclude mollusks and other plant pests, 

e.g., there are no irrigation ditches or other 

openings in which the snails could gain 

access. The greenhouse must be free of 

soil and sand to prevent another potential 

pathway for entry of snails. In addition 

orchids must be stored and packaged in 

Amsacta lactinea, 

Mollusks, 

Scirtothrips dorsalis,

Spodoptera litura, 

Thrips palmi

Bessin et al., 

1997; Hamon, 

1995; 

Hollingsworth 

and Sewake, 

2002
Pest Risk Assessment for Oncidium plants from Taiwan in Growing Media

Ver. 5 May 7, 2012 36

areas free of soil, sand, earth and plant 

pests, which would further aid in 

eliminating snails from the pathway The 

3.5. Program Safeguards to Ensure Compliance

As outlined above the plants in growing media regulation 7 CFR§319.37-8(e) mandates certain 

procedures by APHIS and the plant protection service of the country of origin to ensure 

compliance with the regulation. A written agreement between the plant protection service of the 

country of origin and APHIS outlines the respective responsibilities and obligations for the 

enforcement of the various requirements of 7 CFR§319.37-8(e). This agreement is called the 

“Operational Work Plan”. A current operational work plan for Phalaenopsis plants in growing 

media from Taiwan is in place (APHIS-PPQ, 2004). Before Oncidium plants in growing media 

can be imported from Taiwan, a similar work plan will be developed and signed. 

3.6. Conclusion

The mitigations described in 7 CFR § 319.37-8 (e) are designed to establish and maintain a pestfree production environment and ensure the use of pest-free parent plants. These mitigations, 

when applied to the importation of Oncidium plants in growing media from Taiwan, are highly 

likely to remove the pests of concern identified in the risk assessment from the pathway, thus 

precluding their introduction into the United States. 

4. Authors

Walter A. Gutiérrez, Ph.D.a

Gary L. Cave, Ph.D.a

aUSDA-APHIS-PPQ-CPHST Plant Epidemiology and Risk Analysis Laboratory

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