Commodity risk assessment of plants of 12 selected Prunus species from Moldova

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High-risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by defoliated 1- or 2-year old bare root plants for planting (grafted or not) of 12 Prunus species (Prunus armeniaca, P. avium, P. canescens, P. cerasifera, P. cerasus, P. davidiana, P. domestica, P. dulcis, P. fontanesiana, P. persica, P. salicina, P. tomentosa) imported from Moldova, taking into account the available scientific information, including the technical information provided by the applicant country. The evaluation identified three EU-quarantine pests, Erwinia amylovora (protected zone quarantine pest), Xiphinema rivesi non-EU populations and Xanthomonas arboricola pv. pruni (protected zone quarantine pest), which were selected for further evaluation, based on defined criteria, including their presence in the applicant country. It should be noted that there is uncertainty regarding whether all relevant pests have been identified due to a limited number of scientific publications and pest surveys in Moldova. For the three selected pests, the risk mitigation measures proposed in the technical dossier from Moldova were evaluated taking into account the possible limiting factors. For these pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on it, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with Erwinia amylovora being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9823 and 10,000 bundles (comprising 10-20 plants per bundle) out of 10,000 bundles would be free from E. amylovora.

Diagnostic Tool for the Identification of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) Using Real-Time PCR

Accurate identification of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), commonly known as the Oriental fruit fly, is a significant challenge due to the morphological convergence and taxonomic uncertainties of species belonging to the same genus. This highly polyphagous species poses a significant threat to fruit crops. With its potential establishment in Europe becoming a growing concern, there is an urgent need for rapid and efficient diagnostic methods. The study presented here introduces a diagnostic protocol based on real-time PCR using a TaqMan probe for the early and reproducible identification of B. dorsalis. Specimens representing the genetic diversity of the Italian population were collected and analyzed. Specific primers and probe were designed based on the conserved regions and an in silico analysis confirmed their specificity. The assay conditions were optimized, and analytical sensitivity, specificity, repeatability, and reproducibility were evaluated. The protocol showed high sensitivity and specificity, accurately detecting low DNA concentrations of B. dorsalis. This standardized method provides a reliable tool for routine diagnostics, enhancing the accuracy and efficiency of identifying the Oriental fruit fly at all stages of its development, thereby facilitating effective pest management measures. The development of this diagnostic protocol is crucial for monitoring and supporting efforts to prevent the passive spread of B. dorsalis in Europe, particularly in light of the recent active infestations detected in Italy.

Commodity risk assessment of Malus domestica plants from Bosnia and Herzegovina

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High-risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by bare root plants of Malus domestica grafted on rootstocks of either Malus domestica or Malus sylvestris imported from Bosnia and Herzegovina (BIH), taking into account the available scientific information, including the technical information provided by Bosnia and Herzegovina. All pests associated with the commodities were evaluated against specific criteria for their relevance for this opinion. One protected zone quarantine pest, Erwinia amylovora, fulfilled all relevant criteria and was selected for further evaluation. For E. amylovora, special requirements are specified in Commission Implementing Regulation (EU) 2019/2072. Based on the information provided in the Dossier, these specific requirements for E. amylovora are not met.

Commodity risk assessment of Malus sylvestris plants from United Kingdom

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by rooted plants and bundles of bare root plants or rooted cell grown young plants of Malus sylvestris imported from the UK, taking into account the available scientific information, including the technical information provided by the UK. All pests associated with the commodities were evaluated against specific criteria for their relevance for this opinion. Two quarantine pests (tobacco ringspot virus and tomato ringspot virus), one protected zone quarantine pest (Erwinia amylovora) and four non-regulated pests (Colletotrichum aenigma, Meloidogyne mali, Eulecanium excrescens and Takahashia japonica) that fulfilled all relevant criteria were selected for further evaluation. For Erwinia amylovora, special requirements are specified in Commission Implementing Regulation (EU) 2019/2072. Based on the information provided in the dossier, these specific requirements for E. amylovora are met. For the remaining six pests, the risk mitigation measures proposed in the technical Dossier from the UK were evaluated, taking into account the possible limiting factors. For these pests, expert judgement is given on the likelihood of pest freedom, taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with scales (Eulecanium excrescens and Takahashia japonica) being the pests most frequently expected on the imported bundles of bare root plants or rooted cell grown young plants. The expert knowledge elicitation indicated with 95% certainty that between 9,976 and 10,000 bundles (one bundle consisting of 5-15 plants for bare root plants or 25-50 plants for cell grown young plants) per 10,000 would be free from the above-mentioned scales.

Commodity risk assessment of Malus domestica plants from United Kingdom

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by rooted plants in pots, bundles of bare-rooted plants or trees and bundles of budwood and graftwood of Malus domestica imported from the United Kingdom, taking into account the available scientific information, including the technical information provided by the United Kingdom. All pests associated with the commodities were evaluated against specific criteria for their relevance for this opinion. Two quarantine pests (tobacco ringspot virus and tomato ringspot virus), one protected zone quarantine pest (Erwinia amylovora) and four non-regulated pests (Colletotrichum aenigma, Meloidogyne mali, Eulecanium excrescens, Takahashia japonica) that fulfilled all relevant criteria were selected for further evaluation. For E. amylovora, special requirements are specified in Commission Implementing Regulation (EU) 2019/2072. Based on the information provided in the Dossier, the specific requirements for E. amylovora were met. For the remaining six pests, the risk mitigation measures proposed in the technical Dossier from the UK were evaluated considering the possible limiting factors. For the selected pests, expert judgement is given on the likelihood of pest freedom, taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with scales (E. excrescens and T. japonica) being the pests most frequently expected on the imported budwood and graftwood. The Expert Knowledge Elicitation indicated with 95% certainty that between 9,976 and 10,000 bundles (consisting of 50 up to 500 plants each) per 10,000 would be free from the above-mentioned scales.

Commodity risk assessment of Prunus persica and P. dulcis plants from Türkiye

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by plants of Prunus persica and P. dulcis, as budwood/graftwood, rooted or grafted on rootstocks of either P. persica, P. dulcis, P. armeniaca, P. davidiana or their hybrids, imported from Türkiye, taking into account the available scientific information, including the technical information provided by Türkiye. All pests associated with the commodity were evaluated against specific criteria for their relevance for this opinion. Four quarantine pests (peach rosette mosaic virus, tomato ringspot virus, Anoplophora chinensis, Scirtothrips dorsalis) and 14 non-regulated pests (Hoplolaimus galeatus, Lasiodiplodia pseudotheobromae, Neoscytalidium dimidiatum, Neoscytalidium novaehollandiae, Didesmococcus unifasciatus, Euzophera semifuneralis, Lepidosaphes malicola, Lepidosaphes pistaciae, Maconellicoccus hirsutus, Malacosoma parallela, Nipaecoccus viridis, Phenacoccus solenopsis, Pochazia shantungensis, Russellaspis pustulans) that fulfilled all relevant criteria were selected for further evaluation. For these 18 pests, the risk mitigation measures proposed in the technical Dossier from Türkiye were evaluated taking into account the possible limiting factors. For the selected pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with fungi from Botryosphaeriaceae family (L. pseudotheobromae, N. dimidiatum and N. novaehollandiae) being the pests most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated with 95% certainty that between 9,813 and 10,000 bundles (consisting of 10 or 25 plants each) per 10,000 would be free from the above-mentioned fungi in the Botryosphaeriaceae family.

The spread of Carpophilus truncatus is on the razor's edge between an outbreak and a pest invasion

In 2019, in southern Italy (Campania) there was an outbreak of a sap beetle infesting stored walnut fruits. A monitoring activity started to assess the spread and impact of the pest in walnut orchards and in warehouses, and an integrative characterization led to identify the beetle as Carpophilus truncatus. This species has been in Europe for a long time, rare and harmless until recently. We show also that this species is the same recently recorded in other two continents, Latin America and Australia, where it is causing massive damage on walnut and almond fruits. The sharing of a mitochondrial haplotype among populations recorded on three continents suggests that a worldwide invasion might be ongoing. A Geographic Profiling approach has determined that the more virulent population was first introduced in Italy, and the climate conditions of areas where C. truncatus is currently widespread and harmful indicate that the entire walnuts world production is in jeopardy as this species could adapt to any of the main walnut and almond production areas.

The Bugs in the Bags: The Risk Associated with the Introduction of Small Quantities of Fruit and Plants by Airline Passengers

Simple Summary

This study was carried out with the aim of emphasizing the importance of checking the plant material that can be imported in the baggage of airline passengers. Travelers are often unaware of the regulations in place and of the risks connected with such importation. The risk of the introduction of harmful organisms correlated with this pathway is yet not well studied and its frequency is underestimated. The results of the research underline the need for continuous checks at entry points and the establishment of a specialized position for inspections.

Abstract

Among European countries, Italy is the most exposed to the risk of biological invasions, principally for its numerous entry points (ports and airports) and for climatic conditions favorable for the acclimatization of several invasive species. Here it was assessed that the greatest threats to our agro-ecosystems come mainly from the passenger baggage in which a variety of fruits and vegetables are carried. From 2016 to 2021, large quantities of plant products were found in the luggage of passengers travelling from outside the EU and seized at the BCPs (border control posts) in the Campania region. Inspections and the following laboratory analyses were conducted on the plant material to assess the presence of exotic pests. Inspections led to several non-native species being recorded, and among the intercepted organisms, some should be considered “alarming”, such as Bactrocera dorsalis, Anastrepha obliqua, and Leucinodes africensis. Despite a well-organized border inspection system, travelers transporting infested material unknowingly contribute to increasing the risk of the introduction of exotic species. Given the current situation, it is necessary to impose stricter controls and greater attention, ensuring compliance with the requirements of the new phytosanitary regulations by the actors involved in the transport of plant material. Finally, it is essential to improve awareness through a phytosanitary campaign on plant health risks, especially for people wishing to transport fruits and vegetables in their luggage.

Commodity risk assessment of Prunus domestica plants from Ukraine

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by plants of Prunus domestica grafted on Prunus cerasifera imported from Ukraine, taking into account the available scientific information, including the technical information provided by Ukraine. All pests associated with the commodity were evaluated against specific criteria for their relevance for this opinion. One quarantine pest (Lopholeucaspis japonica), two protected zone quarantine pests (Erwinia amylovora and Xanthomonas arboricola pv. pruni) and one non-regulated pest (Eotetranychus prunicola) that fulfilled all relevant criteria were selected for further evaluation. For these four pests, the risk mitigation measures proposed in the technical dossier from Ukraine were evaluated taking into account the possible limiting factors. For the selected pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with Xanthomonas arboricola pv. pruni being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated with 95% certainty that between 9,870 and 10,000 bundles (consisting of 10 plants each) per 10,000 would be free from Xanthomonas arboricola pv. pruni.

Commodity risk assessment of Malus domestica plants from Turkey

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by dormant grafted plants, rootstocks, budwood and scions of Malus domestica imported from Turkey, taking into account the available scientific information, including the technical information provided by Turkey. All pests associated with the commodities were evaluated against specific criteria for their relevance for this opinion. Three quarantine pests (Anoplophora chinensis, Lopholeucaspis japonica and tomato ringspot virus), one protected zone quarantine pest (Erwinia amylovora) and eight non-regulated pests (Calepitrimerus baileyi, Cenopalpus irani, Cicadatra persica, Diplodia bulgarica, Hoplolaimus galeatus, Malacosoma parallela, Pratylenchus loosi and Pyrolachnus pyri) that fulfilled all relevant criteria were selected for further evaluation. For E. amylovora, special requirements are specified in Commission Implementing Regulation (EU) 2019/2072. Based on the information provided in the dossier, the specific requirements for E. amylovora were not met. For Anoplophora chinensis, special measures are specified in Commission Implementing Decision (EU) 2012/138. The exporting country does meet the requirement for a certificate regarding plants for planting that originate from Turkish provinces other than Istanbul. For the 10 remaining selected pests, the risk mitigation measures proposed in the technical dossier from Turkey were evaluated taking into account the possible limiting factors. For the selected pests an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with D. bulgarica being the pest most frequently expected on the imported plants. The expert knowledge elicitation indicated with 95% certainty that between 9,863 and 10,000 bundles (consisting of 10 or 25 plants each) per 10,000 would be free from D. bulgarica.

Commodity risk assessment of grafted plants of Malus domestica from Moldova

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers plant health risks posed by defoliated and in dormant phase, grafted bare rooted plants for planting of Malus domestica imported from Moldova, taking into account the available scientific information, including the technical information provided by the applicant country. A list of 1,118 pests potentially associated with the commodity species was compiled. The relevance of these pests was assessed following defined criteria and based on evidence. The EU‐quarantine pest Xiphinema rivesi non‐EU populations fulfilled these criteria and was selected for further evaluation. For this pest, the risk mitigation measures proposed in the technical dossier from Moldova were evaluated taking into account the possible limiting factors. For this pest, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on it, including uncertainties associated with the assessment. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,991 and 10,000 plants per 10,000 would be free of X. rivesi.

Commodity risk assessment of Malus domestica plants from Ukraine

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'). This Scientific Opinion covers plant health risks posed by 1- to 3-year-old dormant grafted plants and rootstocks of Malus domestica imported from Ukraine, taking into account the available scientific information, including the technical information provided by Ukraine. All pests associated with the commodity were evaluated against specific criteria for their relevance for this opinion. Two quarantine pests (Lopholeucaspis japonica and Tobacco ringspot virus), one protected zone quarantine pest (Erwinia amylovora) and one non-regulated pest (Eotetranychus prunicola) that fulfilled all relevant criteria were selected for further evaluation. For Erwinia amylovora, for which special requirements are specified in Commission Implementing Regulation (EU) 2019/2072, Annex X, item 9, the fulfilment of these requirements was evaluated. Based on the information provided in the dossier, the specific requirements for Erwinia amylovora were not met. For the three remaining selected pests, the risk mitigation measures proposed in the technical dossier from Ukraine were evaluated taking into account the possible limiting factors. For the selected pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with Eotetranychus prunicola being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated with 95% certainty that between 9,912 and 10,000 bundles (consisting of 50 plants each) per 10,000 would be free from Eotetranychus prunicola.

Rapid Detection of Pityophthorus juglandis (Blackman) (Coleoptera, Curculionidae) with the Loop-Mediated Isothermal Amplification (LAMP) Method

The walnut twig beetle Pityophthorus juglandis is a phloem-boring bark beetle responsible, in association with the ascomycete Geosmithia morbida, for the Thousand Cankers Disease (TCD) of walnut trees. The recent finding of TCD in Europe prompted the development of effective diagnostic protocols for the early detection of members of this insect/fungus complex. Here we report the development of a highly efficient, low-cost, and rapid method for detecting the beetle, or even just its biological traces, from environmental samples: the loop-mediated isothermal amplification (LAMP) assay. The method, designed on the 28S ribosomal RNA gene, showed high specificity and sensitivity, with no cross reactivity to other bark beetles and wood-boring insects. The test was successful even with very small amounts of the target insect’s nucleic acid, with limit values of 0.64 pg/µL and 3.2 pg/µL for WTB adults and frass, respectively. A comparison of the method (both in real time and visual) with conventional PCR did not display significant differences in terms of LoD. This LAMP protocol will enable quick, low-cost, and early detection of P. juglandis in areas with new infestations and for phytosanitary inspections at vulnerable sites (e.g., seaports, airports, loading stations, storage facilities, and wood processing companies).

Short-Term Cold Stress Affects Parasitism on the Asian Chestnut Gall Wasp Dryocosmus kuriphilus

Simple Summary

The Asian cynipid gall wasp (ACGW) “Dryocosmus kuriphilus” has become widespread in Europe. In all invaded areas, it is parasitized by native parasitoids associated with oak galls, for which the ACGW represents a non-saturated adaptation space. Considering the increase in the frequency of extreme climatic events over the last twenty years (e.g., low temperatures during the vegetative period of the chestnut tree), this study aimed to elucidate the effects of cold stress on both ACGW biology and parasitism by native and introduced parasitoids. The ACGW–parasitoid system represents an ideal subject in which to evaluate the effect of sudden cold stress events due to the wasps’ biological characteristics, which include the ability to complete development even in galls detached from plants. We show that parasitism on and the mortality of ACGWs in three chestnut fields were affected by a cold treatment. Our results reveal species-specific differences in the abundance and performance of parasitoids associated with the ACGW in response to cold stress. For example, the frequency of Eupelmus spp. and Mesopolobus tibialis doubled as a result of the cold treatment in all three chestnut fields in both study years. Therefore, the plasticity in response to short-term temperature variation is associated with individual fitness in some parasitoid species.

Abstract

Temperature variation affects interactions involving plants, herbivores, and parasitoids, causing a mismatch between their phenological cycles. In the context of climate change, climatic factors can undergo profound and sudden changes, such as sudden hot or cold snaps. Herein, we show that the number of episodes of short but sustained low temperatures has increased, mainly during May, over the last two decades. We subjected galls induced by the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus to cold stress to assess whether and, if so, how it affected the pest and its parasitoids. Over the course of two years, we measured seasonal parasitism, parasitism rates, the relative abundance of each parasitoid species, and ACGW mortality. We found that the cold treatment affected both the pest and the parasitoids, resulting in a reduction in the emergence of ACGWs and differing ratios of species within the parasitoid community. The most striking example was the change in the relative frequency of three species of Eupelmus spp. and Mesopolobus tibialis, which doubled in cold-stressed galls in all chestnut fields. The effects of temperature on the development of the host and the direct effects of cold temperatures on the surface of galls (in terms of the humidity or hardness of the galls) warrant further research in this direction.

Biological and molecular characterization of Aromia bungii (Faldermann, 1835) (Coleoptera: Cerambycidae), an emerging pest of stone fruits in Europe

The red-necked longhorn beetle (RLB) Aromia bungii (Fald.) is an emerging pest of stone fruit trees, native to East Asia, accidentally introduced in Europe (Germany and Italy) and Japan. Threatening seriously the stone fruit crops in Europe, RLB was added to both the EPPO A1 and priority pest lists of quarantine species. Molecular analyses highlighted that all specimens recovered in southern Italy share the same haplotype, different from the German one, supporting that the invasive process in Europe started from at least two independent introductions. To fill the existing gap of biological knowledge about A. bungii, several laboratory tests were carried out on specimens collected in the outbreak area of Naples (Italy). Results suggest a high biotic potential of the RLB Italian population. Females showed a short pre-oviposition period while the period of oviposition lasted about three weeks, with a rate of 24.2 eggs/day. Each female laid an average of 587.5 eggs and spawned the largest amount of eggs during the first week after emergence. Fed males live up to 62 days at 20 °C while fed females about 63 days at 25 °C. These results are crucial to draw up a multi-facet IPM approach against A. bungii in the outbreak areas.

Aleurocanthus spiniferus (Hemiptera: Aleyrodidae) in Some European Countries: Diffusion, Hosts, Molecular Characterization, and Natural Enemies

After the first record in 2008 in Southeast Italy, the alien invasive and quarantine pest Aleurocanthus spiniferus (orange spiny whitefly-OSW) has gradually spread throughout Europe, infesting several new host plants in addition to the known hosts. Molecular characterization of some Italian populations and a newly found Albanian population highlighted two different haplotypes invading Europe, belonging to one of the haplogroups previously recorded in China. A predator was recorded for the first time in several fields in Italy in association with OSW and other whitefly species. It was successively identified through a morpho-molecular characterization as a Nearctic member of the tribe Serangiini, the ladybird beetle, Delphastus catalinae. This predator represents a promising biocontrol agent to manage A. spiniferus outbreaks in Italy and other invaded countries.

First Record of an Invasive Fruit Fly Belonging to Bactrocera dorsalis Complex (Diptera: Tephritidae) in Europe

Emerging pests are increasingly threatening fruit orchard health across the Mediterranean area. Tephritidae, representing serious threats for Europe, are numerous, and the fruit flies Bactrocera zonata and those belonging to Bactrocera dorsalis complex are among the most alarming species. These species are highly polyphagous and B. zonata has already spread to some Mediterranean countries. Due to these ongoing threats, in the Campania Region (southern Italy), a survey with traps and infested fruits analysis was performed with the aim of detecting the presence of species of Bactrocera dorsalis complex. In two mixed fruit-trees fields, some adults belonging to a species of Bactrocera were captured in traps baited with the highly attractive male lure (methyl eugenol). They were distinguished from similar-looking Bactrocera spp. by morphological and molecular comparative analyses. Considering the existing morphological keys, specimens were tentatively identified as B. dorsalis but molecular characterization with COI split them into two clades. Some specimens were grouped with B. dorsalis similar to B. kandiensis and B. kandiensis and others in a clade including B. dorsalis and B. invadens (syn. B. dorsalis). ITS1 sequences instead confirmed morphological identification. The integrative approach allowed identifying all the specimens collected as belonging to the B. dorsalis complex. This finding represents the first field interception in Europe of a member of one of the most dangerous groups of fruit flies.

Effects of environmental parameters on the chestnut gall wasp and its complex of indigenous parasitoids

The chestnut gall wasp (CGW), Dryocosmus kuriphilus, an invasive pest native to China, has caused severe yield and economic losses to chestnut production in Europe since its arrival in 2002. In Southern Italy, the complex of indigenous parasitoids colonizing CGW was monitored between 2013 and 2015, with the aim of estimating the composition of the indigenous parasitoid complex, its ability to control CGW populations, and the interactions of both factors with several measured environmental parameters. We compared results among three differently managed field types. Results showed an increase in the rate of parasitism both when the host population density was lower and in unmanaged chestnut stands with more natural conditions. The percentage of parasitism in galls was related to morphological traits of the galls and to higher seasonal temperatures, which reduced the parasitism intensity because CGW develops earlier under such conditions. The host-parasitoid mortality inside galls varied among sites and was associated mostly with rot fungi during wet spring and summer months. Parasitoid species richness was similar among the study sites, but the proportion of parasitoid species differed between orchards and unmanaged coppice stands. The timing of attack by parasitoids followed a species-specific successional sequence throughout the larva-to-adult life cycle of the CGW. These interactions should be considered in future research on trophic relationships and when modeling invasive scenarios for new pest species.

Life inside a gall: closeness does not favour horizontal transmission of Rickettsia between a gall wasp and its parasitoid

The incidence of horizontal transmission as a route for spreading symbiont infections is still being debated, but a common view is that horizontal transfers require intimate between-species relationships. Here we study a system that meets ideal requirements for horizontal transmission: the gall wasp Leptocybe invasa and its parasitoid Quadrastichus mendeli (Hymenoptera: Eulophidae). These wasps belong to the same subfamily, spend most of their lives inside the same minute gall and are both infected by Rickettsia, a maternally inherited endosymbiotic bacteria that infects several arthropods, sometimes manipulating their reproduction, like inducing thelytokous parthenogenesis in L. invasa. Despite intimate contact, close phylogenetic relationship and the parasitoid's host specificity, we show that host and parasitoid do not share the same Rickettsia. We provide indirect evidence that Rickettsia infecting Q. mendeli may be inducing thelytokous parthenogenesis, as the symbiont is densely present in the reproductive apparatus and is vertically transmitted. Phylogenetic analyses based on 16S and gltA placed this symbiont in the leech group. The confirmed and presumed parthenogenesis-inducing Rickettsia discovered so far only infect eulophid wasps, and belong to three different groups, suggesting multiple independent evolution of the parthenogenesis inducing phenotype. We also show some degree of cospeciation between Rickettsia and their eulophid hosts.

A new species of <i>Soikiella</i> Nowicki (Hymenoptera: Trichogrammatidae) from Italy

A new species of Soikiella Nowicki (Hymenoptera: Trichogrammatidae) that emerged mostly from galls induced by Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) on chestnut is described from Italy. The characterization of the new taxon, Soikiella italica Viggiani sp. n., was performed through a morpho-molecular approach. A key to the species of Soikiella is given. Emerging from the same samples were a few females of an unidentified species of Trichogramma Westwood that likely emerged from eggs of Lepidoptera associated with the galls. The true host of S. italica is also indicated to be the eggs of some insect other than D. kuriphilus that uses their galls as oviposition sites.

Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae) and of its Rickettsia Endosymbiont, and Associated Sex-Ratio Differences

The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae) is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed.

Characterization, distribution, biology and impact on Italian walnut orchards of the invasive North-American leafminer Coptodisca lucifluella (Lepidoptera: Heliozelidae)

The leafminer Coptodisca sp. (Lepidoptera: Heliozelidae), recently recorded for the first time in Europe on Italian black and common walnut trees, is shown to be the North-American Coptodisca lucifluella (Clemens) based on morphological (forewing pattern) and molecular (cytochrome oxidase c subunit I sequence) evidence. The phylogenetic relatedness of three species feeding on Juglandaceae suggests that C. lucifluella has likely shifted, within the same host plant family, from its original North-American hosts Carya spp. to Juglans spp. Over the few years since its detection, it has established in many regions in Italy and has become a widespread and dominant invasive species. The leafminer completes three to four generations per year, with the first adults emerging in April-May and mature larvae of the last generation starting hibernation in September-October. Although a high larval mortality was recorded in field observations (up to 74%), the impact of the pest was substantial with all leaves infested at the end of the last generation in all 3 years tested. The distribution of the leafminer in the canopy was homogeneous. The species is redescribed and illustrated, a lectotype is designated and a new synonymy is established.

An integrative study of Necremnus Thomson (Hymenoptera: Eulophidae) associated with invasive pests in Europe and North America: taxonomic and ecological implications

The species of Necremnus attacking two invasive pests of tomato and canola in Europe and North America, respectively, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), have been revised using an integrative taxonomy approach. Molecular data from the mitochondrial cytochrome oxidase c subunit I and the nuclear D2 expansion region of the 28S ribosomal subunit and internal transcribed spacer 2, the discovery of new morphological features, and study of type material resulted in the delineation of three species groups, the Necremnus artynes, Necremnus cosconius, and Necremnus tidius groups, the discovery of four new species, and the resurrection of three taxa from synonymy. Lectotypes have been designated for 13 species originally described in Eulophus by Walker. Although Necremnus has not been revised, an illustrated key is given to differentiate 23 recognized European species. The key, type images, and treatments of the three species groups will enable more accurate identification of the valid species of Necremnus in the future. They will also benefit biological control practitioners of pest species. The ecological consequences of the new taxonomic concepts are discussed.

Molecular phylogenetic analyses and morphological variation point to taxonomic problems among four genera of parasitoid doryctine wasps (Hymenoptera : Braconidae)

Doryctinae (Hymenoptera : Braconidae) is a large and diverse subfamily of parasitic wasps that has received much attention recently, with new species and genera described and phylogenies based on morphological and/or molecular data that have improved higher-level classification and species delimitation. However, the status of several genera is still unresolved, if not controversial. Here we focus on two related groups of such genera, Dendrosoter Wesmael–Caenopachys Foerster and Ecphylus Foerster–Sycosoter Picard & Lichtenstein. We integrated morphological and molecular (COI and 28S–D2 genes) evidence to highlight, by phylogenetic analyses (maximum likelihood and Bayesian) and a posteriori morphological examination, previously overlooked variation, which is here illustrated and discussed. Monophyly of Dendrosoter and Caenopachys and the presence of synapomorphic morphological characters support synonymy of Caenopachys under Dendrosoter. Low genetic differentiation and high variability for putatively diagnostic morphological characters found in both C. hartigii (Ratzeburg) and C. caenopachoides (Ruschka) supports synonymy of D. caenopachoides under D. hartigii, syn. nov. Morphological and molecular evidence together also indicate independent generic status for Sycosoter, stat. rev., which is here resurrected. This work represents a further advancement in the framework of the ongoing effort to improve systematics and classification of the subfamily Doryctinae.

First records of the genera Histeromerus Wesmael (Hymenoptera, Braconidae, Histeromerinae) and Ecclitura Kokujev (Hymenoptera, Braconidae, Euphorinae) in Italy

Braconid genera Histeromerus Wesmael, 1838 from subfamily Histeromerinae and Ecclitura Kokujev, 1902 from subfamily Euphorinae are recorded in the fauna of Italy for the first time. The discussions about taxonomic position, morphological characters and composition of these genera as well as the redescriptions of the genus and species of Ecclitura primoris Kokujev are given.

A karyological study of the genus Pnigalio Schrank (Hymenoptera: Eulophidae): assessing the taxonomic utility of chromosomes at the species level

We provide a karyological study of 12 species of the genus Pnigalio in an attempt to evaluate the taxonomic utility of karyotypes at the species level. For all species of Pnigalio examined the number of chromosome was 2n=12. Karyotype formulae presented mainly metacentric and submetacentric chromosomes, although a pair of acrocentrics or subtelocentrics, shorter than biarmed chromosomes, was present in some species. The analysis of karyotypes of Pnigalio showed frequent but not general interspecific variability of the chromosome traits. Although most of the studied species revealed concordance between morphological and karyological characters (centromeric index and relative length), two other categories have been identified: morphologically distinct species without reciprocal differences in karyotype structure, and morphologically similar species that strongly differ in chromosomal characters.

Integration of molecular, ecological, morphological and endosymbiont data for species delimitation within the Pnigalio soemius complex (Hymenoptera: Eulophidae)

Integrative taxonomy is a recently developed approach that uses multiple lines of evidence such as molecular, morphological, ecological and geographical data to test species limits, and it stands as one of the most promising approaches to species delimitation in taxonomically difficult groups. The Pnigalio soemius complex (Hymenoptera: Eulophidae) represents an interesting taxonomical and ecological study case, as it is characterized by a lack of informative morphological characters, deep mitochondrial divergence, and is susceptible to infection by parthenogenesis-inducing Rickettsia. We tested the effectiveness of an integrative taxonomy approach in delimiting species within the P. soemius complex. We analysed two molecular markers (COI and ITS2) using different methods, performed multivariate analysis on morphometric data and exploited ecological data such as host-plant system associations, geographical separation, and the prevalence, type and effects of endosymbiont infection. The challenge of resolving different levels of resolution in the data was met by setting up a formal procedure of data integration within and between conflicting independent lines of evidence. An iterative corroboration process of multiple sources of data eventually indicated the existence of several cryptic species that can be treated as stable taxonomic hypotheses. Furthermore, the integrative approach confirmed a trend towards host specificity within the presumed polyphagous P. soemius and suggested that Rickettsia could have played a major role in the reproductive isolation and genetic diversification of at least two species.

Phenotypic plasticity of pigmentation and morphometric traits in Pnigalio soemius (Hymenoptera: Eulophidae)

Species of the genus Pnigalio Schrank are ectoparasitoids on several pest insects. Most species are polyphagous parasitoids of lepidopteran and dipteran leafminers. Despite their potential economic importance, information on intraspecific phenotypic variability is insufficient. Pnigalio soemius (Walker) was reared at five different temperatures (10, 15, 20, 25, 30 degrees C) on mature larvae of one of its natural hosts, Cosmopterix pulchrimella Chambers (Lepidoptera: Cosmopterigidae), to investigate the influence of temperature on size, colour and other morphological traits, and to measure the range of variation of several characters. Thermal developmental reaction norms, which represent the effect of temperature during growth and development on the value of some adult traits, were produced. The results confirmed the influence of temperature on numerous characters and that these characters had a larger range of variation than realized previously in the construction of taxonomic keys to species. In particular, the number and position of the costulae on the propodeum and colour of the gaster were affected by rearing temperature.