PLANT HEALTH AND BIOSECURITY DIRECTORATE  
CANADIAN FOOD INSPECTION AGENCY  
59 Camelot Drive  
Ottawa, Ontario  
K1A OY9  
Tel: 613-225-2342     FAX: 613-773-7261 RMD -14-03 
Date  
August 21, 201 4 
Title:  Risk Management Document  
 Deregulat ion of Yponomeuta malinellus  (apple ermine moth)  
 
 
 
Preface  
 
As described by the International Plant Protection Convention (IPPC), Pest Risk 
Analysis (PRA) includes three stages: initiation, pest risk assessment and pest risk 
management. Initiating the PR A process involves identifying pests and pathways of 
concern and defining the PRA area. Pest risk assessment provides the scientific basis 
for the overall management of risk. Pest risk management is the process of identifying 
and evaluating potential mitig ation measures which may be applied to reduce the 
identified pest risk to acceptable levels and selecting appropriate measures.   
This Risk Management Document (RMD) includes a summary of the findings of a pest 
risk assessment and records the pest risk mana gement process for the identified issue.  
It is consistent with the principles, terminology and guidelines provided in the IPPC 
standards for pest risk analysis which may be found at https://www.ipp c.int/ . 
August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 2 of 10 Table of Content s 
 
EXECUTIVE SUMMARY  ................................ ................................ ..............................  3 
1.0 PURPOSE  ................................ ................................ ................................ ..............  3 
2.0 SCOPE  ................................ ................................ ................................ ...................  3 
3.0 DEFINITIONS  ................................ ................................ ................................ ...... 3 
4.0 BACKGROUND  ................................ ................................ ................................ ... 3 
5.0 PEST RISK ASSESSMEN T SUMMARY  ................................ ..........................  4 
5.1 Pest Biology  ................................ ................................ ................................ ..............  4 
5.1.1 Life History  ................................ ................................ ................................ ........  4 
5.1.2 Host R ange  ................................ ................................ ................................ .........  5 
5.1.3 Distribution  ................................ ................................ ................................ ........  5 
5.2 Pathways  ................................ ................................ ................................ ...................  5 
5.2.1 Entry Potential  ................................ ................................ ................................ ... 5 
5.2.2 Establishment Potential  ................................ ................................ ......................  5 
5.2.3 Spread Potential  ................................ ................................ ................................ . 6 
5.3 Potential Economic and Environmental Consequences  ................................ ............  6 
6.0 RISK MANAGEMENT CONSIDERATIONS  ................................ ..................  6 
6.1 Plant Protection Regulations  and di rective D -96-02 ................................ ................  6 
6.2 Standards of the International Plant Protection Convention (IPPC)  .........................  7 
6.3 Pest Status and Trade in the Unite d States  ................................ ................................  7 
6.4 Trade and Economic Impacts  ................................ ................................ ....................  8 
7.0 RISK MANAGEMENT DECISION  ................................ ................................ ... 8 
7.1 Consultation  ................................ ................................ ................................ ..............  8 
7.2 Decision  ................................ ................................ ................................ ....................  8 
8.0 REFERENCES  ................................ ................................ ................................ ...... 9 
 
 August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 3 of 10 EXECUTIVE SUMMARY  
 
Yponomeuta m alinellus  (apple ermine moth, AEM) ha s been present in British Columbia 
(B.C.) and the United States  Pacific Northwest states  of Oregon and Washington since 
the early 1980’s. Domestic and import requirements have been applied since 1988 to 
limit the spread  of this pest in Canada.  
 
The most recent Canadian Food Inspection Agency ( CFIA ) pest risk assessment (2009 ) 
demonstrated that Y. malinellus  populations throughout temperate regions of the world 
where apple ( Malus  spp.) is grown are low and below economic threshold s. Based on th is 
updated information, Y. malinellus  is no  longer  considered a pest of economic importance 
and therefore no longer meets the International Plant Protection Convention (IPPC) 
definition of a quarantine pest.  
 
After consultation and d ue consideration of stakeholder comment s, the CFIA is 
deregulating Y. malinellus  in Canada and communicating the decision through this Risk 
Management Document.  
 
1.0 PURPOSE  
 
The purpose of this document is to inform stakeholders and to record a risk manag ement 
decision regarding  the deregulation of  Yponomeuta malinellus (apple ermine moth , 
AEM ). 
 
2.0 SCOPE  
 
This pest Risk Management Document  pertains to Canada’s regulations and policies 
(plant import and domestic  movement) with respect to Yponomeuta malinellus . 
 
Information pertaining to current import requirements for specific plants or plant 
products may be obtained from the CFIA Automated Import Reference System  
[http://airs -sari.inspection.gc.ca/AIRS/airs -sari.asp ].  
 
3.0 DEFINITIONS  
 
Definitions for terms used in the present document can be found in the Plant Health 
Glossary of Terms  [http://www.inspection.gc.ca/plants/pl ant-
protection/directives/glossary/eng/1304730588212/1304730789969] . 
 
4.0 BACKGROUND  
 
Yponomeuta malinellus  was reported in British Columbia  (B.C.) on Vancouver Island 
(1981) , in the Fraser Valley  (1989),  and in the Okanagan Valley and Similkameen Valley  
(1994) . In the United States ( U.S.), Y. malinellus was found in Washington and Oregon in 
1985. It is currently found at low density  in Washington, Oregon and B.C.  
 August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 4 of 10 At the time that  Y. malinellus was first reported in B .C., it was considered to have the 
potential to be a serious pest of Malus  spp. Since that time, reports from both the coastal 
and interior regions of B.C. indicate that its occurrence and impacts have been minimal. 
In commercial orchards, p est management practices used to control other  apple pests 
have  proven to maintain Y. malinellus  populations below economic ally damaging level s.  
 
Yponomeuta  malinellus  is currently considered to be absent from Eastern Canada. Since 
1988, Y. malinellus  has been considered a quarantine pest in Canada and dome stic and 
import requirement s are applied to limit the spread of this pest. In contrast , the U.S. does 
not regulate  Y. malinellus . It has not established  outside the state s of Washington and 
Oregon since it was detected 29 years ago , despite the lack of dom estic controls to 
prevent the movement of this pest .  
 
In 2001, a consultation conducted by CFIA indicated that  even though deregulation of Y. 
malinellus  was supported by many stakeholders, not all  stakeholders  support ed the 
propos al. In 2009 , the pest ris k assessment  for this insect was revised . New evidence 
indicate d that t he overall risk attributed to  Y. malinellus  could be  reduced from medium 
to low. This suggest ed that this pest should no longer be subject to regulatory 
requirements because  it no longe r satisfies the definition of a quarantine pest under  the 
International Plant Protection Convention  (IPPC) . In July 2012, the CFIA initiated a new 
consultation to seek stakeholder input on a proposal to deregulate Y. malinellus . 
Comments received were cons idered in the decision making process  and are reflected in 
this document . 
 
5.0 PEST RISK ASSESSMENT SUMMARY  
 
A pest risk a ssessment (PRA 98 -48) for Y. malinellus  was completed in 1998 and updated 
in 2009  (Dobesberger and Garland, 2009) . An update was requi red to re -evaluate the risk 
associated with this pest according to new available scientific literature  and current 
observation on the status and impact of this pest in North America . The revised pest risk 
assess ment indicate s that the likelihood and  the co nsequence of introduction into all 
regions of Canada are rated medium and low, respectively, resulting in  an overall risk 
rating of low.  
5.1 Pest Biology  
5.1.1  Life History  
 
Yponomeuta malinellus  is known to have one generation per year . Moths are present from 
June/July to September (Cossentine and Kuhlmann , 2000, 2001).  Females feed on nectar 
for about a week as they become sexually mature, mate in the tree crown, and lay eggs in 
masses on young branches in the crown of the host trees  (Carter , 1984).  An av erage of 60 
eggs/mass (14 to 81 eggs/mass) is laid on the bark of young shoots (Carter , 1984; 
Kuhlmann et al. , 1998).  Larvae hatch in early autumn after about 2 weeks, and these 
larvae overwinter under the protective covering of the egg mass ( hibernacula ; Humble 
and Humphre ys, 1989; Kuhlmann et al. , 1998).  In the spring, larvae emerge and begin to August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 5 of 10 mine newly developing leaves in the vicinity.  As larvae grow and develop, they feed on 
leaves within a communal silken tent on shoots (Carter , 1984; Kuhlmann et a l., 1998).  
Mature larvae spin white cocoons that are suspended by silk in rows or clusters along 
tented shoots.  Pupa l develop ment  lasts from 10 to 14 days after which new adults 
emerge.  
5.1.2 Host R ange  
 
The major host of  Y. malinellus  are species of apple  (Malus  spp.). It also has been 
occasionally reported on Pyrus  spp. 
5.1.3 Distribution  
 
Yponomeuta malinellus  is widely distributed throughout temperate areas of the world 
(Carter , 1984).  This includes Europe to the Mediterranean region, North Africa, Asia , and 
the Pacific Northwest of North America (Zhang 1994).  In North America, Y. malinellus  is 
found at low population levels in Oregon, Washington and B.C. (Cossentine and 
Kuhlmann , 2000, 2001).  A single detection on an apple tree in Ontario in 1957 was 
confirmed eradicated (Parker and Schmidt, 1985) . 
5.2 Pathways  
 
The only viable human -assisted pathway is the movement of dormant Malus  spp. nursery 
stock.  Young  larvae overwinter under the protective covering of the egg mass laid on 
young shoots of host tree s, mainly Malus spp. (Unruh et al. , 1993).  Egg masses are 
difficult to detect.  It has long been known that they may be transported in this manner 
from one country to another on dormant nursery stock (Hewitt , 1917).  
5.2.1 Entry Potential  
 
The population le vel of Y. malinellus  throughout temperate regions of the world where 
apple ( Malus  spp.) is grown is generally low and be low economic thresholds.  The risk of 
entry via imported dormant nursery stock is reduced because of low pest population 
levels at source . Yponomeuta malinellus  detection requires detailed visual inspection as 
egg masses are difficult to detect. The potential  of entry of Y. malinellus  on Malus  spp. 
nursery stock is rated as medium . 
5.2.2 Establishment Potential  
 
Apple is cultivated across s outhern Canada as an ornamental and commercially for its 
fruit in British Columbia, Ontario, Quebec, Nova Scotia, New Brunswick and Prince 
Edward Island. Climate modelling indicates that Y. malinellus  could establish in southern 
Ontario and Nova Scotia and  is less likely to establish in Quebec.  The potential  of 
establishment is rated  high.  August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 6 of 10 5.2.3 Spread Potential  
 
Natural spread of Y. malinellus  is slow because adults are weak fliers, and flight is local 
only.  The potential  of natural spread is rated low.  
5.3 Potential Economic and Environmental Consequences  
 
Yponomeuta malinellus  is not considered to be a significant pest of apples  in North 
America and Eurasia (Kuhlmann  et al. , 1998) . In B.C., industry specialists describe Y. 
malinellus  as a pest of very low  or no concern in both nursery and orchards settings in the 
B.C. interior and lower mainland.  The experience with this pest in B.C. and the U.S. has 
also shown that it is infrequent in the landscape.  
 
In agricultural environment s, Y. malinellus  population s levels are maintained below 
economic thresholds through the use of  numerous biological control agents , through the 
use of the biopesticide Bacillus thuringiensis  serovar kurstaki (B.t.k.)  and indirectly, 
through various chemical pesticides  applied to cont rol other pest of Malus  spp. maintain  
(Cossentine and Kuhlmann , 2000, 2001 ; Unruh et al., 2003 ).  
 
It is known that there are natural biocontrols of Y. malinellus  throughout Canada. For 
example, Nemorilla floralis is a tachinid fly that it known to attack the larva  and pupa . 
The ichneumonid , Itoplectis maculator , is also known to attack the larval stage . Some 
species of Balaustium  (predatory mites)  are known to  attack  and kill up to 35% of th e 
eggs of Y. malinellus  (Cossentine and Kuhlmann, 2007) . Natural p redation of Y. 
malinellus  larvae may also occur by insects such as the European earwig, ant s, 
coccinellids and syrphids  (Erven, 1979) . In the Pacific Northwest , the parasitoid  
biocontrol agent Ageniaspis fuscicollis  Dalman  is known to attack  eggs and young  larvae 
and can cause greater than 40% mortality.  
 
Yponomeuta malinellus  is unlikely to reach economic damage thresholds in managed 
environments  including organic fruit produc tion. This pest has not generated  additional 
costs for managed or cultivated envi ronments because  existing practices to produce apple 
have controlled the pest . The potential economic impact is rated low.   
 
Yponomeuta malinellus  is unlikely to degrade the environment, to alter the composition 
of natural ecosystems, or to cause human or animal health problems. The potential 
environmental impact is rated nil.  
 
6.0 RISK MANAGEMENT CONSIDERATIONS  
6.1 Plant Protection Regulation s and directive D -96-02 
 
Yponomeuta malinellus  is included on Canada’s list of regulated pest  and in Schedule II 
(Restricted Movement within Canada) of the Plant Protection Regulations .  
Specific domestic and import requirements for area s infested with  Y. malinellus  are 
outlined in directive  D-96-02, Plant Protection Requirements to Prevent the Introduction August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 7 of 10 and Spread  of Apple Ermine Moth on Malus Specie s. Domestic movement of Malus  
plants from B .C. to the rest of Canada require a com bination of inspection, survey , 
chemical control , and a Movement Certificate . Similarly, t he importation of Malus  plants 
from infested co untries has been required to meet one of the following three 
phytosanitary certification option s: originate from a pest free area ; be produced under a 
chemical control program ; or be subject to post -harvest horticultural oil/water solution or 
fumigation tr eatment.  
6.2 Standards of the International Plant Protection Convention (IPPC)  
 
The Commission on Phytosanitary Measures (CPM) of the IPPC has been designated as a 
standard -setting  phytosanitary  authority of the World Trade Organization.  According to 
the IPPC, contracting parties shall not require phytosanitary measures for non -regulated 
pests . The International Standard for Phytosanitary Measures (ISPM) No. 19, Guidelines 
on Lists of Regulated Pests (IPPC, 2003), requires that pests regulated by National P lant 
Protection Organizations meet the criteria for quarantine or regulated non -quarantine 
pests.   
 
To be considered a quarantine pest , according to the IPPC’s definition, an 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”.   
 
For a plant pest to be deemed to have potential economic importance, t he following 
criteria should be met: 
- a potential for introduction in the PR A area;  
- the potential to spread after establishment; and  
- a potential harmful impact on plants, for example:  
• crops (for example loss of yield or quality)  
• the environment, for example damage to ecosystems, habitats, or species  
• some other specified value, for example recreation, tourism, aesthetics  
(IPPC, 2012 ). 
 
While the pest risk assessment  identifies a potential for introduction and spread within 
Canada, it does not provide any instances where Y. malinellus  is considered to have 
economic importan ce with respect to crops or the environment . 
6.3 Pest Status and T rade in the United States  
 
The U.S. does not regulate Y. malinellus  and the detection of this pest on imported 
shipment s entering the U.S. would not be subjected to regulatory action. Also,  there is no 
regulation of interstate movement of host plants from the Pacific Northwest states where 
it is established.  This observation is noteworthy as apple nursery stock and fruit 
production throughout the U.S. are reliant on nursery stock originating from Washington 
and Oregon where Y. malinellus  is present . Based on official surveys conducted under the 
supervision of the United States Department of Agriculture (USDA), to date Y. malinellus  
has not spread and established outside of Washington or Oregon .  August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 8 of 10 6.4 Trade and Economic Impacts  
 
The pe st risk assess ment indicates that Y. malinellus  is not a pest of significant economic 
importance  in Canada . Deregulation of Y. malinellus  is not expected to affect the volume 
of host plants mov ing in trade. Presently there are very few host species  being exported to 
countries other than the U.S., and New Zealand is Canada’s only current foreign  nursery 
stock  trading partner  that regulate s Y. malinellus . In addition, there are no requirements 
for Y. malinellus  certification for exports to the U .S.  
 
To meet regulatory requirements for Y. malinellus , CFIA resources have been  used to  
deliver the Apple Ermine Moth Program and to survey for the pest outside  of the B.C. 
regulated area.  Nurseries shipping Malus  spp. trees from B.C. to other areas of Canada 
have been required to  implement the Apple Ermine Moth Program and pay associated 
fees.  
 
7.0 RISK MANAGEMENT DECISION  
7.1 Consultation  
 
A Risk Management Proposal (RMP) document p roposing the deregulat ion of  AEM was 
distributed  to horticulture stakeholders for consultation from July 27th to September 27th, 
2012. In the RMP, the CFIA recommended  the deregulation of Y. malinellus  based on the 
following rationale:  
• Yponomeuta malinellu s has been present in North America for c lose to 30 years and is 
considered an inconsequential pest for both conventional and organic apple producers.  
• Yponomeuta malinellus  is present in the U.S. and there are no regulatory measures in 
place to prevent fur ther spread.  Despite this, spread  leading to establishment  has not 
occurred in the U .S. 
• The pest risk assessment concludes that Y. malinellus  poses a low overall pest  risk to 
all regions of Canada . 
• Continued use of public and private resources to mitigate the risk of pest movement 
may no  longer be justified . 
 
Although many stakeholders expressed support for the deregulation of Y. malinellus , 
some stakeholders in Ontario and Quebec expressed concerns regarding the CFIA’s 
proposal.  In spring 2014, further com munication with concerned stakeholders was 
undertak en to respond  to their comments and concerns and provide additional 
information supporting deregulation of Y. malinellus . 
7.2 Decision  
 
After thorough consideration of the scientific information, internati onal obligations, and 
stakeholder comments, the CFIA is announcing, by way of this Risk Management 
Document, the deregulation of Y. malinellus . Yponomeuta malinellus  no longer satisfies 
the definition of a quarantine pest. Current risk analysis demonstrate s that it is not a pest 
of economic importance and its deregulation is necessary to align with the IPPC August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 9 of 10 standards. Yponomeuta malinellus  deregulation aligns with the U.S. approach and will 
facilitate trade.  
  
The CFIA will work towards the removal of Y. ma linellus  from the Schedule II of the 
Plant Protection Regulations in the next regulatory review process.  
  
Until this regulatory change is made and comes into force, the CFIA will revoke policy 
directive D -96-02: Plant Protection Requirements to Prevent th e Introduction and Spread 
of Apple Ermine Moth on Malus Species . The revocation of Directive D -96-02 will take 
effect on August 21, 2014. Moreover, the CFIA will not be taking regulatory action to 
enforce item 4 (35) of  Schedule II of the Plant Protection  Regulations pertaining to the 
domestic movement restriction on apple ( Malus  spp.) plants from any area infested with 
Y. malinellus  (apple ermine moth) to all other areas of Canada.  
  
As part of the implementation of the deregulation, Y. malinellus  will b e removed from 
Canada’s list of regulated pests and the Automated Import Reference Systems (AIRS) 
will be updated to reflect that the importation of apple ( Malus spp.) plants are no longer 
subject to Y. malinellus  requirements. A notification will be circu lated to our trading 
partners through the World Trade Organisation to inform them that Y. malinellus  is 
deregulated in Canada.  
 
8.0 REFERENCES  
 
Carter, D.J. 1984. Pest Lepidoptera of Europe With Special Reference to the British Isles. 
W. Junk, Publ. Series  Entomoligica Vol. 31. 431 pp.  
 
Cossentine, J.E. and Kuhlmann, U. 2000. Status of Ageniaspis fuscicollis (Hymenoptera:  
Encrytidae), an introduced parasitoid of the apple ermine moth 
(Lepidoptera:Yponomeutidae). Canadian -Entomologist 132(5):685 -689. 
 
Cosse ntine, J.E. and Kuhlmann, U. 2001. Yponomeuta malinellus Zeller, Apple Ermine 
Moth (Lepidoptera: Yponomeutidae), pp. 90 -94. In: P.G. Mason and J.T. Huber (eds.),  
Biological Control Programmes against Insects a nd Mites, Weeds and Pathogens in 
Canada 1981 -2000. CABI Publishing, New York, USA.  
 
Cossentine, J. E. and Kuhlmann, U. 2007. Introductions of parasitoids to control the 
apple ermine moth in British Columbia. Pages 13 -19 in C. Vincent, M. S. Goettel, G. 
Lazarovits, eds. Biological Control: A Global Pers pective : Case Studies from Around the 
World. CABI, Wallingford.  
 
Dobesberger, E. and Garland, J.A. 2009 . Plant Health Risk Assessement Yponomeuta 
malinellus  (Apple ermine moth). Canadian Food Inspection Agency. PHD request No. 
98-48 (Update No. 2)  
 August 21, 2014  Risk Management Document – Yponomeuta malinellus  
Page 10 of 10 Erven,  H. 1979. The mixed forest, a model for the management of fruit and vegetables. 
(Does the lesser wood -ant play a role even in biological fruit culture?). Waldhygiene. 
13:1-2. (In German) CAB Abstract.  
 
Hewitt, C.G. 1917. The discovery of the European ermin e moth ( Yponomeuta ) on nursery 
stock imported into Canada. Agric ulture  Gazette of Canada,  Department of Agric ulture ., 
Ottawa , Ontario,  pages 552 -554. 
 
Humble, L.M. and Humphreys, N. 1989. Apple ermine moth in southwestern British 
Columbia. Pest report, Pac ific and Yukon Region, Pacific Forestry Centre, Canadian 
Forestry Service, Natural Resources Canada, 2 pp.  
 
IPPC.  2003 . International Standard for Phytosanitary Measures, ISPM No. 19, Guidelines 
on Lists of Regulated Pests, Secretariat of the International  Plant Protection Convention, 
Food and Agriculture Organization of the United Nation, Rome, Italy.  
 
IPPC. 2012. International Standard for Phytosanitary Measures, ISPM No.5, Glossary of 
phytosanitary terms,  Supplement No. 2., Guidelines on the understandin g of potential 
economic importance and related terms including reference to environmental 
considerations, Secretariat of the International Plant Protection Convention, Food and 
Agriculture Organization of the United Nation, Rome, Italy.  
 
Kuhlmann, U., Carl , K.P. and Mills , N.J.  1998. Quantifying the impact of insect 
predators and parasitoids on populations of the apple ermine moth, Yponomeuta 
malinellus  (Lepidoptera: Yponomeutidae), in Europe. Bulletin of Entomol ogical  
Research  88:165 -175. 
 
LaGasa, E., Unru h, T.R. and Haskett , M. 1993. Apple ermine moth – Orchard Pest 
Management Online, Washington State University.  
[http://jenny.tfrec.wsu.edu/opm/displaySpecies.php?pn=620 ] 
 
Parker, D.J.  and Schmidt, A.C. 1985. Apple ermine moth, Yponomeuta malinellus . 
Report for Agriculture Agri -Food Canada, Plant Health Division.  
 
Unruh, T.R., Congdon , B.D. and LaGasa , E. 1993. Yponomeuta malinellus Zeller 
(Lepidoptera: Yponomeutidae), a new immigrant p est of apples in the northwest:  
phenology and distribution expansion, with notes on efficacy of natural enemies. Pan -
Pacific Entomol ogist  69:57 -70. 
 
Unruh, T., Short, R., Herard, F., Chen, K., Hopper, K., Pemberton, R., Lee, J. H., Ertle, 
L., Swan, K., Fue ster, R. and others. 2003. Introduction and establishment of parasitoids 
for the biological control of the apple ermine moth, Yponomeuta malinellus  (Lepidoptera: 
Yponomeutidae), in the Pacific Northwest. Biological Control 28:332 -345. 
 
Zhang, B.C. 1994. In dex of Economically Important Lepidoptera. CAB Int ernationa l, 
Wallingford, U.K. 599 pp.