Pour la protection des plantes 10- 16120 Report of a Pest Risk Analysis for Bactrocera invadens




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EUROPEAN AND MEDITERRANEAN PLANT PROTECTION ORGANIZATION

ORGANISATION EUROPEENNE ET MEDITERRANEENNE
POUR LA PROTECTION DES PLANTES


10- 16120

Report of a Pest Risk Analysis for Bactrocera invadens
This summary presents the main features of a pest risk analysis which has been conducted on the pest, according to EPPO Decision support scheme for quarantine pests.


Pest:

Bactrocera invadens

PRA area: The PRA area is the EPPO region (see map www.eppo.org).

Assessors:

The Expert Working Group for PRA for Bactrocera invadens. A preliminary draft was prepared by José María Guitián Castrillón, Diana Catalan Ruescas and the EPPO Secretariat. This document was reviewed by an Expert Working Group composed of: Marc De Meyer1, Denis Félicité Zulma2, Catherine Guichard2, Jose Maria Guitián Castrillon3, Alan MacLeod4, Frédéric Plumelle5, Serge Quilici6, Nursen Üstün7, Jean-François Vaysières8 on 2009-12-07/10.
1Royal Museum for Central Africa, Leuvensesteenweg 13, B-3080 Tervuren (BE)

2 Comité de Liaison Europe-Afrique- Caraïbes-Pacifique (COLEACP)

3 Tecnologias y Servicios Agrarios, S. A. - TRAGSATEC, C / Hnos. Garcia Noblejas, 37C. 2a Planta, 280037 Madrid (ES)

4 The Food and Environment Research Agency Sand Hutton, York YO41 1LZ (UK)

5 Plumelle Consulting (FR)

6 UMR "Peuplements Végétaux et Bio-agresseurs en Milieu Tropical", CIRAD Réunion (FR)

7 Plant Protection Research Institute, 35040, Bornova, Izmir (TR)

8 IITA-CIRAD / Biological Control Center for Africa, 08 B.P. 0932 Tri Postal Cotonou, Rép.du Bénin (BJ)



Date:

Expert Working Group 2009-12 Core member consultation 2010-05 Panel on Phytosanitary Measures conference call 2010-05-26







STAGE 1: INITIATION


Reason for doing PRA:


Since 2003, a new fruit fly species, morphologically very similar to B. dorsalis, has been reported spreading rapidly throughout Sub Saharan Africa. This new pest is attacking cultivated and local tropical fruits (e.g. mangoes, guava, papaya, Citrus spp., etc.). It was described in 2005 and called Bactrocera invadens (Drew et al., 2005).

Taxonomic position of pest:

Diptera: Tephritidae







STAGE 2: PEST RISK ASSESSMENT


Probability of introduction

Entry




Geographical distribution:

B. invadens is believed to be native to Asia. Following the discovery of this species in Kenya in 2003, R. A. I. Drew (Brisbane, Australia) examined specimens collected in Sri Lanka in 1993 by K. Tsuruta (Yokohama, Japan) during his survey of the island. He found that B.invadens had previously been overlooked as unusual variants of several other species. This discovery confirms that the native range of B. invadens includes Sri Lanka, where it is not known to have any status as a pest.

The native range is likely to be larger than currently reported, since specimens may be misidentified as other representatives of the complex (de Meyer et al., 2009). It is not clear whether Buthan should be considered as part of the native area (de Meyer et al., 2009).
Asia: Bhutan, India, Sri Lanka.
Note: The species occurs in India, and it has been recorded for the first time in 2005 in Tamil Nadu in mango orchards, and it was particularly dominant in Chennai (Sithanantham et al., 2006).
Africa: Angola, Benin (first found 2004-06), Burkina Faso (2005-05), Burundi (2008-11), Cameroon (2004-08), Central African Republic (2008-08), Chad, Congo (2005-11), Comoros (2005-08), Côte d’Ivoire (2005-05), Democratic Republic of Congo, Equatorial Guinea, Ethiopia (2004-07), Gabon, Gambia (2005-06), Ghana (2004-11), Guinea (2005-05), Guinea-Bissau (2005-07), Kenya (2003-02), Liberia (2005-07), Mali (2005-06), Mauritania (2007-08), Mayotte (France) (2007-03), Mozambique (2007-07), Namibia (2008-10), Niger (2005-08), Nigeria (2003-11), Senegal (2004-06), Sierra Leone (2005-07), Sudan (2004-05), Tanzania (2003-07), Togo (2004-10), Uganda (2004-07), Zambia (2008).

Note: Its first place of discovery (i.e. Kenya) should not be assumed to be its point of entry into Africa, as it may have been overlooked in some areas.




Major host plants or habitats:


B. invadens is highly polyphagous, it has more than 40 known cultivated and wild hosts in Benin (Vayssières et al., 2009), and is expected to have as broad a host range as some other members in the B. dorsalis complex. All hosts are recorded from Africa; there are no data available on hosts within the native range of B. invadens in Asia (Mwatawala et al., 2009).

Among major hosts are mango (Mangifera indica) and guava (Psidium guajava) (CABI, 2007), the list of major and minor hosts is presented in Appendix 1.




Which pathway(s) is the pest likely to be introduced on:

The EWG considered that B. invadens was likely to enter the PRA area with the following pathways


  • Fruits of major hosts from countries where the pest occurs;

  • Fruits of minor hosts from countries where the pest occurs;

  • Plants for planting with growing medium attached from countries where the pest occurs;

  • Fruits carried by passengers from countries where the pest occurs;

  • Natural spread.

The information provided for pathways are based on the situation in Africa. Data for the native region is missing.


Fruits from countries where the pest is known to occur

Fruits in trade infested with eggs, larvae and (rarely) pupae represent the most likely pathway, although it is unknown how B. invadens was introduced from Asia to Africa (EPPO, 2005). According to the Europhyt database (EU Member states only), 1291 consignments of fruits and vegetables infested with non-European Tephritidae were intercepted between 1993 and 2009, and 158 consignments infested with Bactrocera spp. were intercepted for the same period and the same commodities. These records may be underestimated, as in Roissy airport (France), the presence of non-European Tephritidae resulted in 273 notifications of non-compliance in 2009 alone. For 175 intercepted consignements, larvae were raised to the adult stage, among which 39 were identified as B. invadens. Additionally, French interceptions of B. invadens between 2007 and 2010 (as of May 2010) are as follows : 19 for 2010 from Cameroon and Togo; 39 in 2009 from Senegal, Mali, Kenya, Burkina-Faso, Côte d'Ivoire, Togo, Cameroon; 18 in 2008 from Cameroon, Côte d'Ivoire, Mali, Burkina-Faso, Senegal); 1 in 2007 from Cameroon (French NPPOs, pers. comm., 2010).

Switzerland has recently intercepted B. invadens on mango consignments from Cameroon (EPPO, 2009). Since 2006 the UK (Fera) have intercepted and detected it ten times; once in 2010 on Psidium guajava from Sri Lanka and nine times on Mango from Senegal (5), Gambia (2), Ghana (1) and Kenya (1).
B. invadens may infest many host plants (more than 40 host species recorded in Appendix 1), and this highly polyphagous species is being found on an increasing number of hosts; the current host list is not considered as definitive. Although more host plants are likely to be reported, they are probably of minor significance in international trade. The EWG considered that a distinction should be made between major hosts and minor hosts as risks of entry were perceived to be different.

The host fruits are divided into 2 categories called major and minor hosts.



Major hosts:

- a regular host that is usually relatively highly infested;

- a major host for which a large proportion of the samples is infested, number of flies emerging is often very high.
The following species are considered as major hosts:

Annona muricata (Sour sop), Carica papaya, Chrysophyllum albidum, Citrus x paradisi (grapefruit), Citrus reticulata, Citrus sinensis, Citrus x tangelo, Diospyros montana, Eriobotrya japonica, Fortunella japonica, Fortunella margarita, Irvingia gabonensis, Mangifera indica, Psidium guava, Psidium littorale, Spondias cytherea, Spondias mombin, Terminalia catappa, Thevetia peruviana, Vitellaria paradoxa.
Minor hosts

- an incidental host, with only one or a few records, usually with low infestation rate;

- a host that is used more regularly, but often with very low infestation rate. This can also be a host for which there are only few positive rearings, but with considerable numbers of flies emerging.
The following species are considered as minor hosts:

Anacardium occidentale (Cashew), Annona cherimola, Annona senegalensis, Annona squamosa (sugar apple), Averrhoa carambola (star fruit), Blighia sp., Capsicum annuum (sweet pepper), Capsicum frutescens (chilli pepper), Citrullus lanatus (watermelon), Citrus aurantium, Citrus grandis (pomelo), Citrus limon, Coffea arabica (Arabica coffee) and C. canephora (Robusta coffee), Cordia sp. cf myxa, Cordyla pinnata, Cucumis figarei, Cucumis sp nr metuliferus, Cucumis pepo,Cucumis sativus (cucumber), Cucurbita maxima, Cucurbita spp. (pumpkins), Flacourtia indica, Lycopersicon esculentum (tomato), Malus domestica (apple), Manilkara sapota (bully tree), Momordica cf trifoliata, Musa spp. (banana), Musa x paradisiaca, Persea americana (avocado), Prunus persica (peach), Sarcocephalus latifolius, Sclerocarya birrea, Solanum aethiopicum, Solanum anguivi, Solanum incanum, Solanum nigrum, Solanum sodomeum, Sorindeia madagascariensis, Strychnos mellodora, Sizygium cumini, Sizygium jambos, Sizygium malaccense (Malay apple) and Sizygium samarangense and Ziziphus mauritiana.
- Plants for planting with growing medium attached from countries where the pest is known to occur

The main risk for plants for planting is when fruits are present on the plants. Fruits on host plants could be infested with eggs, larvae and (rarely) pupae of Bactrocera invadens.

The EWG noted that entry of planting material (trees and shrubs) with fruits attached from areas where the pest is currently present is prohibited by some phytosanitary legislation in the EPPO region (e.g. EU legislation), but considered that the situation could change (the pest could spread further or legislations could change).

Although the import of a plant species with fruit attached is restricted, pupae could be present in the growing media attached to the plants. This pathway was mentioned during EPPO ad hoc workshops on Pest Risk Analysis of non-European fruit flies in 1993 and 1994.


- Fruits carried by passengers

White & Elson-Harris (1992) report that many fruit fly outbreaks may be attributable to undetected imports of a few fruits in an airline passenger's baggage. This has also been recognized in later studies (Miller, 1997). Passengers could potentially bring back fruits from countries they visit that may be contaminated with B. invadens.

Passengers in cars, trains, ferries and buses between tropical Africa and the Mediterranean area are also a pathway.

Passengers bringing contaminated plants for planting are considered unlikely and are not considered further.


Other pathways not considered further in the PRA

- Natural spread

It is unlikely that B. invadens could enter the Mediterranean EPPO region by natural means in the near future.



- Fruits of hosts in mail

Fruits of hosts can be sent in mail either by individuals or by private companies. This pathway is not considered further as it is considered unlikely due to the price of sending fruit by mail. Nevertheless, whilst admittedly a minor pathway this does exist as Fera PHSI, UK intercepted 24 illegal imports of fruit in mail from July 2009 – April 2010, mainly Malus spp., Citrus spp. and Mangifera indica (Paul Bartlett, pers comm., 2010).



- Cut branches with fruits used for ornamental purposes

On flower markets, cut branches with fruits such as Coffea arabica and Coffea canephora are a new niche, used for ornamental purposes. This has been observed in Rungis (D. Félicité-Zulma, pers. comm., 2009). This pathway is considered negligable.



- Hitchhiker on commodities

This is a theoretical pathway which has never been recorded. It is very unlikely that flying adults would hide in containers, they would usually rather fly away. This pathway is therefore considered very unlikely.



- Growing media in non host plants for planting

Pupae could be present in the growing media accompanying non host plants for planting which have been grown in the vicinity of contaminated hosts. This pathway is considered to be very unlikely.



- Soil as a commodity

Pupae could be present in soil imported as a commodity. This pathway is usually prohibited.



- Soil attached to machinery

Pupae could be present in the soil attached to machinery. This pathway has never been reported for Tephritidae and is considered very unlikely.




Establishment




Plants or habitats at risk in the PRA area:


B. invadens appears to be highly polyphagous as it counts more than 40 cultivated and wild hosts.

The main major hosts cultivated in the EPPO region are Mangifera indica, Citrus spp., Psidium guajava, and Carica papaya.

The main minor hosts cultivated in the EPPO region include: Citrullus lanatus, Cucumis sativus, Capsicum annuum, Capsicum frutescens, Cucurbita sp., Lycopersicum esculentum, Malus domestica, Musa spp., Persea americana, etc.
The total production area in hectares for fruit and vegetable hosts of Bactrocera invadens in the EPPO region and neighbouring countries for 2008 are shown below:

Country

Producing area in ha in EPPO countries and potential members in 2008

Malus domestica (Apples)

1 699 828

Persea americana (Avocados)

33 208

Musa spp. (Bananas)

88 071

Capsicum spp. (Chillies and peppers, green)

309 170

Citrus spp.

17 192

Cucumis sativus (Cucumbers & gherkins)

402 616

Mangifera indica, Garcinia mangostana (Mangoes, mangosteens) & Psidium guava (guavas)

135 031

Carica papaya (Papayas)

522

Prunus persica (Peaches & nectarines)

491 923

Cucurbita spp.& Cucumis pepo (Pumpkins, squash & gourds)

233 344

Lycopersicon esculentum (Tomatoes)

1 700 416

Citrullus lanatus (Watermelons)

784 872

Source: FAOSTAT.

Some of these species and many other hosts are used as ornamental plants in the EPPO region and can be planted in public and private gardens: Anacardium occidentale, Eriobotrya japonica, Fortunella margarita, etc. (see Appendix 1).


Moreover, B. invadens is currently enlarging its host range in Africa (see Appendix 1) (Vayssières et al., 2005), and it could also adapt to additional hosts (e.g. stone fruits such as peaches) when arriving in the EPPO region.
In the southern part of the EPPO region (particularly Citrus producing countries), major hosts (Citrus spp., Mangifera indica, etc.) and minor hosts (such as Capsicum spp., Citrullus lanatus, Cucumis spp., Lycopersicum esculentum, Musa spp.) are cultivated outdoors as crops. These species and other hosts might be used as ornamental plants in public and private gardens and along road sides.

Hosts are therefore present in cultivated fields and/or in gardens throughout the year and could allow B. invadens to complete several life cycles all year round.

For example in the Mediterranean area:

- from September till June, Citrus spp. are available,

- from July to November, mangoes are available,

- from May till September, fruits of other hosts are available.




Climatic similarity of present distribution with PRA area (or parts thereof):


Cold temperatures and low relative humidity are considered the most important abiotic parameters that would affect B. invadens establishment. Because the species continues to spread, the limits of its climatic tolerance are not yet precisely known. The hottest and most humid parts of the Mediterranean Basin, more or less corresponding to the citrus growing area, are considered to be the most at risk.
A climatic prediction analysis performed by Hurt & Takeuchi (2006) with NAPPFAST, concludes that entire African continent (including North Africa) has a high potential for the establishment of B. invadens. The model estimated the lowest number of generations per year in southern and northern parts of Africa (having a Mediterranean type climate); however, B. invadens is still predicted to have as many as 6 generations per year in those areas. For continental US, 0 to 5 generations were predicted (Hurt & Takeuchi, 2006).
According to a CLIMEX analysis, the countries of the Mediterranean basin that are considered to be particularly at risk (including non EPPO countries) from the establishement of B. invadens are: Algeria, Egypt, Jordan, Israel, Libya, Morocco, and Tunisia (Fig 1 & 2).

Figure 1: Potential distribution of B. invadens in the Mediterranean Basin (Ecoclimatic index) with CLIMEX



Figure 2: Potential distribution of B. invadens in the Mediterranean Basin with CLIMEX with irrigation scenario (Ecoclimatic index)


CLIMEX data also shows that establishment is not expected to occur in other Mediterranean countries although B. invadens could enter regularly with fruits and this may result in the occurrence of local transient populations. The species could develop up to 5 generations in Albania, France (Corsica), Cyprus, Croatia, Greece (Crete), Italy (Sardinia, Sicily), Lebanon, Portugal, Spain, Syria, Turkey (Fig 3). In comparison to Central Africa, the population build-up of these local transient populations is expected to be low. Spain is particularly at risk as the species could spread naturally if it became established in Morocco.

Figure 3: Number of generations of B. invadens superior to 5 in the Mediterranean Basin, with irrigation scenario


The tolerance of the species to cold temperatures and to dry conditions remain the two major uncertainties. The species could adapt to new conditions in the Mediterranean and have a wider distribution than the one described above.
The EPPO workshop on non-European fruit flies held in 1993 concluded that fruit flies are not considered to present a risk in glasshouse crops in Northern Europe. The EWG was unable to confirm this statement due to uncertainties concerning the range of authorized active ingredients under changing EU regulation or disruption of biological control practices in greenhouses. The risk of a greenhouse getting infested in Northern Europe by B. invadens remains very unlikely and is not considered further in the PRA. In the Southern region, the risk of glasshouses being infested is low, and very uncertain.







Characteristics (other than climatic) of the PRA area that would favour establishment:


Considering that the species spends most of its development phase inside fruits, abiotic factors other than climatic conditions are probably of minor importance for establishment.

There is no information on soil preference for the part of the life cycle of the species that is spent in the soil.




Which part of the PRA area is the endangered area:


The endangered area includes the horticultural and fruit-growing areas in Algeria, Egypt, Jordan, Israel, Libya, Morocco, and Tunisia.

In other Mediterranean countries, establishment is not expected to occur although B. invadens could enter regularly with fruits and this may result in the occurrence of local transient populations (see above), this area is consequently considered as part of the endangered area.

It also includes trees planted as amenity trees in private and public areas and home gardens.








POTENTIAL ECONOMIC CONSEQUENCES

How much economic impact does the pest have in its present distribution:


B. invadens is currently considered as one of the major pests in Africa (Mwatawala et al., 2009). In general, B. invadens is displacing indigenous fruit flies in Africa (Ekesi et al., 2006).

Quantitative data on crop losses are only available for mango and citrus species.


Mangoes

CTA (2007) considers that because of attacks by Ceratitis cosyra and Bactrocera invadens, harvest losses on mangoes that are about 10% at the beginning of the growing season can reach 80% by the end of the season. Sampling of infested fruits at regular intervals during the mango season indicates that late cultivars are attacked much more than early ones.



In Western Africa, Vayssières et al. (2008) also found that for the cultivars Amélie (Gouverneur), Eldon, Dabschar, Kent, Smith, Keitt and Brooks together, losses stand at 15% in early April and exceed 69% in mid-June (the end of the mango season). Average losses were measured on 12 orchards in Borgou in Benin in 2005 and 2006 (see table 1).

Cultivars of mango

Losses in % in 2005

Losses in % in 2006

Average losses in % for 2005 and 2006

 

Gouverneur

14.8

15.8

15.3

 

Eldon

44.0

49.4

46.7

 

Amelioree

50.5

47.3

48.9

 

Dabschar

50.7

47.9

49.3

 

Kent

51.6

47.5

49.6

 

Smith

54.5

55.5

55.0

 

Keitt

62.8

60.8

61.8

 

Alphonse

65.0

64.2

64.6

 

Brooks

65.5

73.1

69.3

Table 1: losses on mango production in Benin expressed in percentages for different varieties for the years 2005 and 2006, experiment performed by JF Vayssières.
Losses attributed to Tephritidae had been extrapolated at the hectare scale on the basis of sampled mangoes and losses recorded on this sample. Losses were estimated to vary between 0.34 tonnes/ha, and 6.5 tonnes/ha (from 15% to 69%), depending on the cultivar (Vayssières et al., 2008).

Oviposition in the fruit can also lead to a number of pathogen attacks that can accelerate the damage to the fruit (Vayssières et al., 2008).


Citrus spp.

In Kenya, Rwamushana et al. (2008) reported heavy infestations on Citrus limon, C. reticulata and C. sinensis. It is extrapolated that heavy infestations could have impacts on the crop. The level of infestation depends on Citrus hosts as well as on the agro-ecological zone. In South Benin, from all citrus fruits sampled in 2008-2009, emerged fruit fly species were mostly B. invadens (98.3%) and the resulted damages depended on the locality and the Citrus species. In 2008, the recorded incidence on mandarin (Citrus reticulata Blanco) was 46.7% and 36.7% in orchards in Amoussa (Glo locality) and Monou (Sakété), respectively. On Tangelo (Citrus x tangelo), the incidence was 33.3% in the orchard in Amoussa. On sweet orange (Citrus sinensis) (cv Valencia) the incidence was 30.0%, 20.0%, 20.0% and 17.8% in orchards in Amoussa, Agban (Allada), Houéssou (Allada) and Monou, respectively. In terms of infestation rates (number of pupae per kg of fruit), on mandarin these were 25.6 and 22.4 in orchards in Monou and Amoussa, whereas in Tangelo these were 19.7 in the orchard in Amoussa. On sweet orange, the infestation rates were 8.7, 7.0, 5.3 and 3.0 in orchards in Amoussa, Monou, Agban and Houéssou respectively. This incidence level, due mostly to B. invadens, is an indication that, in South Benin, B. invadens is the most destructive and economically important fruit fly in Citrus resulting in great yield losses (see table 2 for average losses for 2 years). As the crop is an important income provider for the producers and the country, a proper control method elaboration is urgently needed to reduce the yield losses, increase income and alleviate poverty.

In other countries such as Ghana, Guinea, Togo and Senegal the situation is similar to that in Benin and was sometimes even worse. In central Tanzania, C. paradisi seems to be the more heavily infested species.


 

Guinean zone

Sudanian zone

Citrus tangelo (Tangelo)

34%

?

Citrus reticulata (Mandarin)

22%

6%

Citrus sinensis (Sweet orange)

25%

12%

Citrus x paradisii (Grapefruit)

?

10%


Table 2: performed losses assessments on Citrus species in Benin between November 2007 and November 2009 in the Guinean and the Sudanian zones. Bactrocera invadens causes about 90% of the damage observed. Results are expressed in percentages of losses of production, studies implemented by JF Vayssières et al. (unpublished data).


Describe damage to potential hosts in PRA area:


As is the case for other fruit flies, attacked fruit will usually show signs of oviposition punctures. Fruit with a high sugar content will exude a sugary liquid, which usually solidifies adjacent to the oviposition site.

Damage on Mangoes (CIRAD, 2008)





How much economic impact would the pest have in the PRA area:

In this section, no distinction is made between potential impacts for the areas where the species could establish, and where the species could be transient. After incidental introduction, transient populations could develop up to 5 generations per year. Impacts in areas where populations are only transient are expected to be lower as the populations would build up slowly, and damage would only be localized.
The countries in the endangered area produce 100% of bananas, mangoes, papayas, citrus and avocados that are produced in the EPPO region; almost 95% of peaches and nectarines; and nearly 80% of peppers and 75% of tomatoes.

According to EFSA (2007), the cooler conditions in the endangered area and the fact that there is better integrated pest management (IPM) practice and crop hygiene in orchards reduces the impacts compared with those recorded in the current range of the pest.

These figures do not include home-garden production, which could be substantial, but for which no information is available.
Major hosts

Mangifera indica

According to FAOSTAT, 37 852 tonnes of mango are cultivated in the EPPO region, mainly in Israel (37 827 tonnes) and Morocco (25 tonnes). This crop is not as important in the EPPO region as it is in most of Africa. The EWG noted that FAOSTAT does not report mango production in Spain, while such production occurs, particularly in the Canary Islands (JM Guitián Castrillón, pers. comm., 2009).

Distribution of Mangifera indica in the world, from CABI, 2007

Legend: red dots indicate that the species is widespread


Citrus spp.

Citrus spp. is a major crop in the EPPO region and is produced all around the Mediterranean area (Morocco, Spain, Italy, Greece, Turkey, etc.). See table 1.
Distribution of Citrus spp. in the world, from CABI, 2007

Legend: red dots indicate that the species is widespread


Carica papaya

In the EPPO region papayas are only produced in Israel, Morocco and Tunisia according to FAOSTAT. See table 1.



Commodity

TOTAL produced in tonnes in 2007 in the EPPO region

Citrus spp.

16 215 868

Carica papaya

425

Table 1: Production in tonnes of Citrus species and papayas in the EPPO region for 2007

Source: FAOSTAT. Details by country are available in Appendix 2.


Distribution of Carica papaya in the world, from CABI, 2007

Legend: red dots indicate that the species is widespread

The EWG considered that in the absence of control measures, the impact on major hosts (mango, citrus species and papayas) in the endangered area would be high.
Minor hosts

Impacts on minor hosts such as apples, watermelons, peaches and peppers are low in the current range of the species. The production in tonnes for 2007 in the EPPO region of crops at risk are provided in table 2.




Commodity

Production in the EPPO region in tonnes in 2007

Lycopersicon esculentum (Tomatoes)

36 593 790

Malus domestica (Apples)

18 888 307

Citrullus lanatus (Watermelon)

11 301 569

Cucumis sativus (Cucumbers & gherkins)

7 943 042

Capsicum spp. (Chillies and peppers, green)

5 626 987

Prunus persica (Peaches & nectarines)

5 307 329

Cucurbita spp.& Cucumis pepo (Pumpkins, squash & gourds)

3 839 177

Musa spp. (Bananas)

567 062

Persea americana (Avocados)

243 851

Table 2: Total tonnes of produced fruits and vegetables hosts of Bactrocera invadens in the EPPO region for 2007.

Source: FAOSTAT.


In addition to losses in crop yield, impact on exports are also expected.







CONCLUSIONS OF PEST RISK ASSESSMENT


Summarize the major factors that influence the acceptability of the risk from this pest:

  • many cultivated hosts are available in the Southern part of the EPPO region;

  • a succession of fruits from suitable hosts are available all year round;

  • climatic conditions seem suitable in at least some parts of EPPO countries.

  • there are few active ingredients available to control tephritids, and the current management methods would not prevent the establishment of B. invadens;

  • eradication of the pest (outdoors) is very difficult without early detection and rapid emergency response;

  • B. invadens, as is the case for most tephritids, is characterized by a high fecundity and a short life cycle.






Estimate the probability of entry:

Fruits of major and minor hosts

Major hosts such as Mangifera indica (mango), Psidium guajava (guava), Carica papaya (papaya) and Citrus spp. (citrus) represent a likely pathway for the entry of B. invadens. The concentration of the pest on these fruits is considered to be high. Uncertainty is low.


Minor hosts such as Capsicum annuum, Capsicum frutescens, Citrullus lanatus, Cucumis melo, Cucumis sativus, Cucurbita sp., Lycopersicum esculentum, Malus domestica, Musa sp., Persea americana and Prunus persica (peach) represent a moderately likely pathway. The concentration of the pest on these fruits is considered to be lower than on major hosts.

Uncertainty is low.


Plants for planting with growing media

The uncertainty on this pathway is high.

It is moderately likely that plants for planting with fruits could provide a pathway for the entry of B. invadens, but it is currently a closed pathway for many EPPO countries.

It is unlikely that plants for planting with growing media of hosts provide a pathway for the entry of B. invadens, entering as pupae in the growing media.

Prohibition for plants of Solanaceae, Citrus spp. and Fortunella spp. when they are implemented by EPPO countries, prevent the entry of B. invadens.
Fruits carried by passengers

It is moderately likely that infested fruits carried by passengers provide a pathway of entry for B. invadens.


- Natural spread

It is unlikely that B. invadens could enter the Mediterranean EPPO region by natural means in the near future.


It is to be noted that the establishment in any Mediterranean third country, or the Canary Islands would increase the risk of entry from all pathways, especially Citrus and tomato fruit imports and plants for planting (some current restrictions would no longer apply, e.g. no prohibition for Solanaceae).






Estimate the probability of establishment:


The countries of the Mediterranean basin that are considered to be particularly at risk (including non EPPO countries) because B. invadens could establish there are: Algeria, Egypt, Jordan, Israel, Libya, Morocco, and Tunisia.
In other Mediterranean countries, establishment is not expected but B. invadens could enter regularly with fruits and this may result in the occurrence of local transient populations.
The uncertainty on the establishment of B. invadens in the southern EPPO region remains medium and is mainly associated with the suitability of climatic conditions.





Estimate the potential economic impact:


Both direct and indirect impact are expected to occur if the pest becomes established or to a lesser extent if transient population occur.

Crops particularly at risk are Mangifera indica, Citrus spp. and Carica papaya, and there is an uncertainty on the potential impacts on other crops which are currently minor hosts in its current range: Musa spp., Citrullus lanatus, Cucumis sativus, Capsicum spp., Cucurbita spp., Persea americana, Malus domestica, Lycopersicum esculentum, etc.

It is suspected that in the endangered area, peaches or other stone fruits could become major hosts.

The overall uncertainty on the economic impact is considered medium to high.







Degree of uncertainty

The overall level of uncertainty is considered as medium to high.
Host species

B. invadens seems to have an increasing host range in Africa, and it is unknown whether it would adapt to alternative hosts (eg. stone fruits) present in the endangered area.

There is no indication of the species' host range in its native range.


Climatic requirements

There is a lack of data on the limiting factors of the species (e.g. cold and drought resistance) and its ability to establish in temperate areas.


Spread capacity

There is no precise data available on the flight ability of B. invadens, and there is also an uncertainty on the succession of available hosts at different seasons in all parts of the endangered area.


Impact on crops

There is a major uncertainty on the potential impacts on the following crops in the endangered area: Musa spp., Citrullus lanatus, Cucumis sativus, Capsicum spp., Cucurbita spp., Persea americana, Malus domestica, Lycopersicum esculentum, stone fruits, etc.


Interceptions

No information is available for non EU EPPO countries, except for Switzerland


Adaptability

The potential adaptability of the pest is unknown. This includes the possibility of adaptation to protected cultivation, as several of the hosts are commonly grown in glasshouses in the EPPO region, whereas this is rarely the case in those areas where the pest is known to be present at this time.







OVERALL CONCLUSIONS


The pest is an appropriate candidate for the management stage.




Stage 3: PEST RISK MANAGEMENT
IDENTIFICATION OF THE PATHWAYS

Pathways studied in the pest risk management

  • Fruits of major and minor hosts from countries where the pest occurs

  • Plants for planting with growing medium attached

  • Fruits carried by passengers




Other pathways identified but not studied


(see entry part)


  • Pathway 1: Fruits of major and minor hosts from countries where the pest is known to occur

Measures related to consignments:

For fruits originating from areas of low pest prevalence: post-harvest treatment


Measures related to the crop or to places of production:

  1. Fruits should originate in a pest free area for fruit flies ISPM 26 establishment of pest-free areas for fruit flies (Tephritidae) should be followed.




    • Areas of low pest prevalence

  1. pest free places of production

The measures required to determine a free place of production are:

- absence of any detection in Methyl Eugenol traps in places of production and the vicinity during a period to be determined:

(OPTION a) since the beginning of the last complete cycle of vegetation/

(OPTION b) Methyl Eugenol traps could be restricted to the seasons when susceptible hosts are present in the place of production and its vicinity.

- A buffer zone adapted to the flying ability of the pest, the potential existence of natural barriers, and the presence of hosts should preferably be established. Such situations could occur in the sub Saharan area and in Mali. It should be noted that establishing a buffer zone is difficult due to the flying ability of the pest over long distances, and its polyphagy.

- monitoring of traps should be done on a weekly basis under the authority of the NPPO.

- sanitation with the removal of fallen fruits should be mandatory.

- in addition, examination for absence of signs of the pest on the fruits before harvest at the place of production should take place under the authority of the NPPO.


    • Areas other than areas of low pest prevalence

  1. Systems Approach (ISPM no. 14) Measures can be applied pre and post-harvest wherever the NPPO can oversee and ensure compliance1. Suggested measures against the fruit flies of concern are:


Pre-harvest:

Integrated Pest Management Measures (based on fruit fly monitoring around the production site, sanitation, male annihilation techniques, biocontrol, ploughing, agronomic practices, cultural practices, removal of reservoir hosts, bait station)

Bagging of fruits when feasible
Harvest:

Harvest at earliest possible maturity level


Post-harvest:

Inspection of fruits before packing and sorting out injured fruits and proper disposal of waste

Cold treatment for Citrus spp. and pome fruits (Malus sp., Pyrus sp.), or adequate treatment for other commodity.



  1. Measures recommended for the establishment of Pest free place of production in an area of low pest prevalence and adequate post-harvest treatment in areas other than of low prevalence


Possible impact on trade of these measures

Similar requirements are implemented in EPPO countries for exports to certain countries because of Ceratitis capitata.



Pest free areas

This option would affect imports of fruits from areas where the pest occurs, particularly Africa. Major exporters for the major hosts are mainly situated in Latin America, and importers in the EPPO region could find alternative sources there to substitute African origins.



Pest free place of production

This measure is difficult to implement. The management and maintenance of a buffer zone might increase the price of the fruits. There are few expected social or environmental consequences in EPPO countries, but it depends on the number of places of production that can be effectively implemented. A small number of possible places of production would have similar consequences as a pest free area.



Systems approach

The management at the place of production and post-harvest quarantine treatment might increase the price of the fruits. Fumigation with methyl bromide has a negative impact on the environment.




  • Pathway 2: Plants for planting with growing media

Measures related to consignments:

  • Import of young plants (plants too young to fruit) or

  • Import in a dormant stage or

  • Removal of fruits 1 month prior to export


Measures related to the crop or to places of production:

The plants should be grown

- Under protected conditions or

- Pest free place of production or

- Pest free area
Possible impact on trade of these measures

These measures are common measures for plants for planting.



  • Pathway 3: fruits carried by passengers

  • the requirement of a phytosanitary certificate for passengers traveling with fruits

  • publicity to enhance public awareness on pest risks.

  • fines and incentives

Possible impact on trade of these measures

These measures have no impact on trade but could have an impact for the NPPOs of the countries concerned.


Other possible measures

Trapping is a particularly important method for the early detection of outbreaks and should be used as a component of the early warning systems within the PRA area. Methyl Eugenol traps could be used for monitoring the presence of this invasive pest. Many countries that are free of Bactrocera spp., e.g. certain States of the USA and New Zealand, maintain a grid of ME traps, at least in ports and airports (CABI, 2007).

In case of any detection, a contingency plan aiming at eradication should be immediately implemented.

However, these measure would not guaranty the prevention of establishment of the pest.


EVALUATION OF THE MEASURES IDENTIFIED IN RELATION TO THE RISKS PRESENTED BY THE PATHWAYS



Degree of uncertainty

Uncertainties in the management part are:

Efficacy of the treatments for B. invadens

Efficacy of the option pest free place of production or of a systems approach as described, these are recommended on the basis of current practices.

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