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NAME OF THE ORGANISM: Cacopsylla (1CCPSG)

GENERAL INFORMATION ON THE PEST

Name as submitted in the project specification (if different):

Pest category:

Insecta

1- Identity of the pest/Level of taxonomic listing:

Is the organism clearly a single taxonomic entity and can it be adequately distinguished from other entities of the same rank?

Yes

Is the pest defined at the species level or lower?:

Can listing of the pest at a taxonomic level higher than species be supported by scientific reasons or can species be identified within the taxonomic rank which are the (main) pests of concern?

No: Fruits (including hops) sector

If necessary, please list the species:

Cacopsylla species feeding on Pyrus in the west Paleartic are C. bidens, C. fera, C. notata, C.permixta, C. pyri, C. pyricola, C. pyrisuga (Burckhardt and Hodkinson, 1986). Economically relevant species in Europe on pear are C. bidens, C. pyri, C. pyricola and C. pyrisuga
There are few data on Cacopsylla species on Cydonia: C. mali (Ellis, 2001-2024) and C. melanoneura (Ossianilsson 1992).
Species with economic relevance in apple are C. melanoneura (Förster, 1948), C. mali (Schmidberger, 1836) and C. picta (Förster 1848). Additionally, 13 other Cacopsylla species have been found on apples (in Italy, Fischnaller et al. 2017). Regarding the reported developmental hosts of these insect species, however, it rather seems that these psyllids are only occasionally present on apple.

Is it justified that the pest is listed at a taxonomic rank below species level?

Not relevant

Conclusion:

Candidate: Fruits (including hops) sector

Justification (if necessary):

Species of Cacopsylla differ substantially from one another in biology. Some species are economically important, others not. Evaluation continues at species level.
In the responses to the questionnaire, AT, DE, ES, FR, NL and SI considered that Cacopsylla was a pest of concern. AT supported listing at genus since species identification was not providing any extra value for control; whereas most of the responding countries (DE, ES, FR and NL) supported listing at species level (host specificity, morphological differentiation is possible). SI supported deregulation in the EU (see pathway). Assessment will continue providing information (when possible) at species level.

2 – Status in the EU:

Is this pest already a quarantine pest for the whole EU?

Presence in the EU:

Yes

List of countries (EPPO Global Database):

Conclusion:

Candidate

Justification (if necessary):

For Pyrus (Ossianilsson, 1992; Burckhard and Hodkinson 1986; Etropolska et al. 2015): Pear sucker species are widespread relevant pests in European pear orchards (Civolani et al. 2023 for review)
- C. bidens: Bulgaria, France, Grece, Italy.
- C. pyri: Austria, Bulgaria, Czech Republic, Denmark, France, Greece, Hungary, Italy, Malta, The Netherlands, Portugal, Slovenia, Slovakia, Spain, Sweden, Switzerland, Turkey.
- C. pyricola: Austria, Belgium, Bulgaria, Czech Republic, Croatia, France, Germany, Great Britain, Greece, Hungary, Italy, Malta, The Netherlands, Poland, Portugal, Romania, Slovenia, Slovakia, Spain, Sweden, Switzerland, Turkey.
- C. pyrisuga: Austria, Bulgaria, Czech Republic, France, Germany, Great Britain, Greece, Slovakia, Switzerland, Italy, Georgia, Denmark, Sweden, Norway

For Cydonia (De Jong et al., 2015, Ellis, 2001-2024, Ossianilsson, 1992): The mentioned Cacopsylla species are widespread in Europe, however data for Cydonia as a (reproductive) host are rare.
- C. mali (Schmidberger, 1836): On Malus, occasionally found on Cydonia and Pyrus. It is reported in Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Italy, Ireland, Netherlands, Poland, Romania, Slovakia, Slovenia, Sweden Austria, Denmark, Italy, Sweden,
- C. melanoneura (Förster 1948): On Rosaceae, occasionally on Cydonia. Austria (Riedle-Bauer, personal observation), Czech Republic, Denmark, Finland, Germany (Jarausch B., personal communication), Italy, Norway, Poland, Slovenia, Sweden, Spain, Türkiye.

For Malus (De Jong et al. 2015, Ellis, 2001-2024, Ossianilsson, 1992): C. picta, C. melanoneura and C. mali are regularly occuring in wide parts of Europe.
- C. mali (Schmidberger, 1836) on Malus, occasionally found on Cydonia and Pyrus. It is reported in Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Italy, Ireland, Netherlands, Poland, Romania, Slovakia, Slovenia, Sweden Austria, Denmark, Italy, Sweden.
- C. melanoneura (Förster 1948): On Rosaceae, mainly Crataegus but regularly on Malus. It is present in Austria (Riedle-Bauer, personal observation), Czech Republic, Denmark, Finland, Germany (Jarausch B., personal communication), Italy, Norway, Poland, Slovenia, Sweden, Spain, Türkiye.
- C. picta (Förster 1848): On Malus, present in Austria, Belgium, Czech Republic, Finland, France, Germany, Italy, Poland, Slovakia, Slovenia, Sweden, Spain

HOST PLANT N°1: Pyrus (1PYUG) for the Fruits (including hops) sector.

Origin of the listing:

Commission Implementing Directive (EU) 2014/98/EU (previous version)

Plants for planting:

Plants intended for planting

3 - Is the pest already listed in a PM4 standard on the concerned host plant?

Conclusion:

Evaluation continues

4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):

Conclusion:

Not candidate

Justification:

C.pyrisuga has a migratory life cycle. It estivates and overwinters on conifers. In early spring, the overwintered adults migrate to Pyrus on a regional scale. Although it is possible that plants for planting are infested, their role for insect distribution is minor.

All other Cacopsylla species mentioned above are group are multivoltine and overwinter in reproductive diapause as a seasonally distinctive form or morphotype. An important trait of at least some species in this group is dispersal from pear by the winterform generation. This activity has been extensively studied for North American populations of C. pyricola. A varying percentage of the winterform population leaves the pear orchards in autumn and overwinters on non- host shelter plants. This behavior leads to relevant redistribution of individuals between orchards. Warm and dry autumns lead to higher percentages of dispersing individuals (Civolani et al. 2023, for review). An evaluation of gut contents of C. pyricola in autumn by molecular means in USA revealed feeding activity on 18 plant families (Cooper et al. 2019), overwintering on apple was also observed (Horton and Lewis, 2011). The migration behavior of winter-form C. pyri and C. bidens seem to be less pronounced, nevertheless both species have been collected from stone and pome fruit trees in Winter (Civolani et al. 2023, for review).
C. pyricola, now widespread in North America, is native from Europe. It was introduced to USA in the early 1800s with pear seedlings from Europe (Horton, 2008).
The fact that C. pyricola was introduced into USA by pear seedling indicates that infested plants for planting (Horton, 2008) can be relevant for spread of the mentioned species. Given the extended infestations of pear orchards with C. pyri (Civolani, 2012) and C. pyricola (e.g. Trapman & Blommers, 1992, Riedle-Bauer et al. 2022) in many parts of Europe, however, it is not likely that Cacopsylla spp. mainly spread through specific plants for planting.

[Remark: In the responses to the questionnaire, SI commented that Cacopsylla spp. are not mainly transmitted by plants for planting.]
For all these species, the Fruit SEWG considered that plants for planting should not be considered as a significant pathway.

5 - Economic impact:

Are there documented reports of any economic impact on the host?

Yes

Justification:

Cacopsylla pyri, C. pyricola and C. bidens are notorious pests of commercial pears. High-density populations of these insects can cause several types of damage: fruit russet, psylla shock and pear decline (for some psyllids). The nymphs secrete copious quantities of honeydew. If this honeydew is in contact with fruit for a significant period of time it causes dark blotches or streaks on the surface of the fruit (russetting), which in turn results in downgrading of the fruit at harvest (Burts, 1970 in Nin et al., 2012). Fruit russet is of most concern to growers, and control programs are generally directed at preventing this injury, since it can be caused by relatively low population densities (Burts, 1988; Nin et al., 2012). Psylla shock is caused by feeding nymphs in high density and can lead to premature leaf and fruit drop, diminish plant growth, and reduce fruit size. Flowers attacked by first generation nymphs turn brown and die. Feeding later in the season may affect the harvest of the next year by weakening or killing fruit buds (Pfeiffer & Burts, 1983; Shaltiel-Harpaz et al., 2018). Cacopsylla pyri, C. pyricola and C. pyrisuga are vectors of ‘Candidatus Phytoplasma pyri’ that causes pear decline disease (Weintraub & Beanland, 2006; Riedle-Bauer et al., 2022).
Pear psylla were shown to rapidly acquire inherited resistance to pesticides, limiting the choice of efficacious chemicals for its control, and causing a constant increase in applied concentrations. This comes into conflict with consumer demand for lower pesticide application in the orchards and forms an obstacle to efficient integrated pest management in pear orchards (Shaltiel-Harpaz et al., 2018)
Pear psyllid is estimated to cost the UK pear industry £5 million per annum and has a significant economic impact on pear production globally (Reeves et al., 2024).
[Remark: In the responses to the questionnaire, AT questioned whether direct damage was acceptable. DE expressed reservations to list them as vectors of RNQPs.]

What is the likely economic impact of the pest irrespective of its infestation source in the absence of phytosanitary measures? (= official measures)

Major

Is the economic impact due to the presence of the pest on the named host plant for planting, acceptable to the propagation and end user sectors concerned?

Is there unacceptable economic impact caused to other hosts (or the same host with a different intended use) produced at the same place of production due to the transfer of the pest from the named host plant for planting?

Conclusion:

Justification:

Pear psylla were shown to rapidly acquire inherited resistance to pesticides, limiting the choice of efficacious chemicals for its control, and causing a constant increase in applied concentrations. This comes into conflict with consumer demand for lower pesticide application in the orchards and forms an obstacle to efficient integrated pest management in pear orchards (Shaltiel-Harpaz et al., 2018)

6 - Are there feasible and effective measures available to prevent the presence of the pest on the plants for planting at an incidence above a certain threshold (including zero) to avoid an unacceptable economic impact as regards the relevant host plants?

Conclusion:

Justification:

C. pyrisuga constantly remigrates to pear orchards over several weeks in spring (e.g. illustrated in Riedle-Bauer et al. 2022). Studies on the closely related plum sucker C. pruni (Paleskic et al. 2017) indicate that insecticide application over six to eight weeks at early developmental stages of the trees i) imply several treatments with knock down insecticides (environmental effects?)and ii)will rather not fully prevent the presence and feeding of remigrating Cacopsylla individuals on pear plants.

As stated above, all above mentioned Cacopsylla species except C. pyrisuga colonize the pear trees during a vast part of the year, and leave and move back to pear from autumn to early spring. Any attempt to prevent insect presence on mother plants or nursery plants would require numerous treatments all year round. Treatment success is severely endangered by the risk of resistance development against active ingredients. From autumn to spring, the time most relevant for phytoplasma transmission (Riedle-Bauer et al. 2022), insecticide effects are in addition hampered by cool temperatures, and plant dormancy or very early stages of plant development (as reported for C. pruni by Paleskic et al. 2017). Overall high numbers of pesticide applications would i) encounter undesired side effects without ii) fully reaching the goal to ensure freedom pf pears from Cacopsylla spp..

7- Is the quality of the data sufficient to recommend the pest to be listed as a RNQP?

Conclusion:

Justification:

CONCLUSION ON THE STATUS:

Disqualified: plants for planting are not considered to be a significant pathway and feasible and effective measures available to prevent the presence of the pest on the plants for planting are lacking.

8 - Tolerance level:

Is there a need to change the Tolerance level:

No (listed in a previous version of Commission Implementing Directive (EU) 2014/98/EU)

Proposed Tolerance levels:

9 - Risk management measures:

Is there a need to change the Risk management measure:

Proposed Risk management measure:

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