Cynipidae Research Articles

Use of biocontrol agents as potential tools in the management of chestnut blight

Castanea sativa is a widespread and important multi-purpose tree in the Mediterranean area. Recently, intensive infestation of gall wasp decreased the production of chestnut, and makes the plants more susceptible to Cryphonectria parasitica, the causal agent of chestnut blight. Generally, biological control of chestnut blight is through natural spread or artificial release of hypovirulent strains of C. parasitica. However, this approach is not always successful. The aim here was to evaluate alternative approaches for control chestnut blight based on application of antagonistic microorganisms. In-vitro antagonistic activities of fungal species Trichoderma and Penicillium were tested after in vitro isolation from chestnut bark. In dual cultures, these antagonistic fungi consistently reduced growth of C. parasitica. Three commercial formulations based on Trichoderma spp., Glomus spp. and Bacillus subtilis were tested at three doses, both in vitro and directly applied to cuttings of chestnut stems as co-inoculations and as separated inoculations with C. parasitica mycelium plugs. With co-inoculation, B. subtilis showed the best performance against chestnut blight, with necrotic areas reduced by >70%. In separated inoculations, B. subtilis reduced the size of cankers on chestnut stems, by 29%–67%, as also for Trichoderma spp., by 36%–65%, and Glomus spp., by 31%–63%. Application of commercial formulations based on antagonistic microorganisms are effective tools in management of chestnut blight.

A Comprehensive Review about Quercus infectoria G. Olivier Gall

Due to an interaction between gall wasp Andricus sternlichti Bellido and Quercus infectoria G.Olivier from Fagaceae, the oak galls with a wide range of industrial and pharmaceutical applications are produced. Quercus infectoria galls have been well-known by both ethnopharmacology and traditional medicine of Iran. The aim of current study was a comprehensive collection of Persian scholars' notions and recent findings about medicinal effects of this gall. Sixteen traditional manuscripts of one millennium were sought by two keywords (“Afs” and “Mazu”. Arabic and Persian names of Quercus gall, respectively), and relevant articles till October 2018 were reviewed. In traditional manuscripts, three main dosage forms from gall including decoction, powder, and poultice were found. They had been prescribed for about of thirty disorders. Except for one clinical trial, other articles described related to animal studies and antimicrobial effect evaluation. Since Quercus infectoria gall as an endemic natural product of Iran is a valuable source for export, ethnic usages and pharmaceutical applications, the outcomes of this study can be beneficial for researchers involved in development of natural medications.

Efficacy of Three Insecticides in the Control Gall Wasp Leptocybe invasa in Eucalyptus urograndis Seedlings

Forestry expertise and plantations managers are struggling to find cheaper and sustainable solutions to contain the losses caused by Leptocybe invasa in the last nine years on the forest stands in Mozambique. Aiming to help find a solution in the control of L. invasa early in the nursery, we conducted an experimental trial at the Niassa Forestry company nursery, located in the Niassa province, northern Mozambique in February 2015. Three insecticides: Acetamiprid, Thiamethoxam, Imidacloprid, with and without adherent and pH regulator were tested. The experiment had seven treatments including the control. The number of seedlings infested by the gall wasp were assessed 15, 30, 45 and 60 days after the seeds were sown in the nursery. Data were analysed in R package. Normality and homogeneity of variances were tested through Shapiro-Wilk and Bartlett's tests respectively. Analysis of Variance (ANOVA) and parametric means test (Tukey-HSD), were used to assess whether there was difference among the treatments. Results showed difference between treatments at 0.01% of significance after 15, 30 and 45 days and at 5% in the 60 days after sowing. With less seedlings infested by the gall wasp, Imidacloprid with and without adherent was almost superior compared to all other pesticides in all assessment. The use of adherent and pH regulators negatively affected the performance of insecticides, except in the Imidacloprid. This study findings should not however, be overall generalized, instead, more research can be conducted to verify the consistency of these results before being widely implemented.

Ophelimus sp., a new invasive gall wasp of Eucalyptus globulus in Europe, escapes the parasitism by Closterocerus chamaeleon due to an asynchronous life cycle

Ophelimus sp. (Hym: Eulophidae) is an Australian gall wasp newly found in Southern Europe forming galls on Eucalyptus globulus. A congeneric gall wasp O. maskelli, also established in the Mediterranean Basin, is currently controlled by the introduced parasitoid Closterocerus chamaeleon. To date, no parasitism was observed on Ophelimus sp. by C. chamaeleon. Here we analyze a possible escape from parasitism through an asynchronous life cycle in this host-parasitoid system. The ability of C. chamaeleon to oviposit and complete development on Ophelimus sp. was determined, both in laboratory and field experiments. Ophelimus sp. showed to be univoltine, with winter larval development and possible summer egg diapause, contrasting with the multivoltine behavior of O. maskelli, which completes 3–4 generations per year. Concomitantly, C. chamaeleon is normally collected in the field from May to October. In laboratory, under low temperatures (15 ± 1 °C), adults of the parasitoid could survive up to four months. Both old (86–89 days) and young (<16 days) parasitoid females showed similar parasitism behavior. Naïve parasitoid females oviposited in both O. maskelli (on E. camaldulensis) and Ophelimus sp. (on E. globulus), with no apparent preference between the two host species. We observed parasitism, when we exposed adults of C. chamaeleon to bagged eucalypt leaves infested with Ophelimus sp. galls, in field conditions. Altogether, our results demonstrate that C. chamaeleon is able to oviposit and complete development in Ophelimus sp. However, in field conditions, the lack of parasitism is possibly due to life cycle asynchrony between the parasitoid and the gall wasp.

BUILDING TWO HOUSES ON A SINGLE HOST PLANT: GALLING INSECT SYNCHRONIZES ITS LIFE CYCLE WITH PLANT PHENOLOGY

Galls are specific interactions between specialist herbivores and their host plants. They are considered neoformed plant organs developed from cellular hypertrophy, tissue hyperplasia and cellular redifferentiation of the host tissues. Among several organisms capable of inducing galls, insects induce them with high morphological complexity. The induction and development of galls depend on the availability of responsive sites in the host plant that react to the chemical and/or mechanical stimuli of galling insects. The synchronization between the timing of availability of these responsive sites and the galling insect life cycle is essential for the establishment of the interaction. Galling insects are subject to several chemical, physiological and phenological changes in their host plant. Thus, changes in the host cycle may alter the insect's life cycle, distribution and abundance. This study focused on the morphological aspects and phenological relationship of the Matayba guianensis Aubl. (Sapindaceae) – Bystracoccus mataybae Hodgson, Isaias & Oliveira (Eriococcidae) system, carried out in a semi-deciduous forest located at the Estacao Ecologica do Panga (EEP), Uberlândia, MG, Brazil. We monitored the host plant phenology monthly from April 2015 to April 2016, and galls were sampled throughout the year to determine the stage of development of the galling insect. During leaf flushing, galling insects were collected every two days. The second-instar nymph induced leaf galls during leaf sprouting (peaks in September and October). The growth, development and maturation of the gall and of the galling insect occur concomitant to leaf maturation (peaks from February to May). Before the first leaves fall (August), the first-instar nymph moves from the senescent leaflet gall to branches and induces a stem gall, where it remains during part of the dry season until the next leaf flush. The synchrony between the life cycle of the galling insect and the host plant phenology maintains the univoltine cycle.

THE PRESENT PEST STATUS OF EUCALYPTUS SAP-SUCKERS AND GALL WASPS IN CAMPANIA (ITALY)

ap-suckers and gall wasps may be a severe phytosanitary problem for several Eucalyptusspecies, particularlyfor the red gum E. camaldulensis, the most widely cultivated Australian native tree species worldwide. This paperreviewed the harmfulness of some of these invasive pests established in Campania, and provides new information abouttheir pest status

Identification of the parasitoid community associated with an outbreaking gall wasp, Zapatella davisae, and their relative abundances in New England and Long Island, New York.

Gall wasps (Hymenoptera: Cynipidae) are phytophagous insects that often go unnoticed; however, when they are introduced to a new area or released from their natural enemies, they have the capacity to outbreak and cause extensive foliar damage. One such outbreaking pest, Zapatella davisae (Cynipidae: Cynipini), causes significant damage and mortality to black oak, Quercus velutina, in the northeastern United States. In this study, we aimed to identify the parasitoid community associated with Z. davisae, compare differences in percent parasitism of Z. davisae in Cape Cod and Long Island, and determine which parasitoid species contribute most to parasitism in each region. From both locations, we reared parasitoids, identified morphological groups, analyzed percent parasitism rates for each group, and used DNA barcoding to provide species‐level identifications. On Long Island, there was nearly 100% parasitism in 2015 followed by a near total collapse of the population in 2016. In contrast, parasitism rates were lower and remained consistent on Cape Cod between 2015 and 2016, which may explain the greater canopy damage observed in that region. Species of Sycophila were the dominant parasitoids, with one species Sycophila nr. novascotiae representing ~65% of reared parasitoids from Long Island, and two species of Sycophila (S. nr. novascotiae and S. foliatae) with near equal representations on Cape Cod. In order to manage an insect pest, it is important to understand factors that influence its mortality and survival. An understanding of how these infestations progress overtime can help predict the impact that newer infestations in Nantucket, MA, and coastal Rhode Island will have on black oak populations and will aid in the management of this rapidly spreading gall wasp pest.

Seasonal flight activity and genetic relatedness of Torymus species in Italy

Abstract Torymus sinensis Kamijo was released into Europe to control the Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu, proving to be an effective biocontrol agent. In Japan, hybrids between this exotic parasitoid and the native congeneric Torymus beneficus Yasumatsu and Kamijo have been recorded, whereas no case of hybridization with natives has been reported for Europe. The seasonal phenology of the Torymus species was investigated in north‐west Italy and 172 997 chestnut galls (Castanea spp.), 7866 oak galls (Quercus spp.), 29 wild rose galls (Rosa spp.) and 44 bramble galls (Rubus spp.) were collected over a 5‐year period. The seasonal flight activity was recorded for eight native Torymus species [Torymus affinis (Fonscolombe), Torymus auratus (Müller), Torymus bedeguaris (L.), Torymus calcaratus Nees, Torymus cyaneus Walker, Torymus flavipes (Walker), Torymus geranii (Walker) and Torymus notatus (Walker)] and five of them were found to overlap with T. sinensis flight, namely T. affinis, T. auratus, T. flavipes, T. geranii and T. notatus. Among the Torymus native species, T. notatus revealed to be morphologically and phylogenetically closely related to T. sinensis, thus suggesting hybridization potential.

Cynipid gall wasps

Egan et al. introduce the reader to gall wasps, including a description of their life cycle and complex ecological interactions with host plants and natural enemies.

Development of microsatellite markers for an outbreaking species of oak gall wasp,Zapatella davisae(Hymenoptera: Cynipidae), in the northeastern United States

Populations of the recently described black oak gall wasp, Zapatella davisae Buffington (Hymenoptera: Cynipidae), have been identified as the cause of extensive tree damage and mortality to black oaks, Quercus velutina Lamarck (Fagales: Fagaceae), in the northeastern United States. Relatively little is known, however, about the distribution, phylogenetic placement, and lifecycle of this important tree pest. Therefore, we conducted next-generation sequencing using the Ion Torrent™ PGM (ThermoFisher Scientific, Inc.) platform to develop genomic resources for the study of Z. davisae and for other closely related species of oak gall wasps. Individual sequence reads were aligned, assembled into unique contigs, and the contigs were then utilized for the in silico isolation and development of microsatellite markers. In total, we screened 36 candidate microsatellite loci, of which 23 amplified consistently (five polymorphic and 18 monomorphic). We then examined whether the polymorphic loci could be used to infer whether populations of Z. davisae from Cape Cod and Nantucket are sexual or asexual by calculating several metrics of genetic diversity that might indicate the mode of reproduction. These included testing for statistical deviations from Hardy-Weinberg equilibrium (HWE) and for linkage disequilibrium (LD), observations for the presence of the Meselson effect, and by calculating the probability that clonal individuals are more prevalent than would be expected in a randomly mating population. While we found significant deviations from HWE and more clonal individuals than expected, our estimates of the Meselson effect were inconclusive due to limited sampling, and we found no evidence of LD. Therefore, the sexual/asexual status of Z. davisae populations remains uncertain.

A forest canopy as a living archipelago: Why phylogenetic isolation may increase and age decrease diversity

AbstractAimAn individual tree resembles a living island, a small spatially distinct unit upon which colonizers maintain populations. However, several differences exist compared to oceanic islands: a tree is relatively young, is composed of numerous differently aged branches, may be phylogenetically isolated from neighbours, and some of its colonizers are specific to particular tree lineages. We suggest that these specificities strongly affect both alpha‐ and beta‐diversity within trees, including positive effects of isolation on the diversity of generalists, and strengthening of the effect of isolation with tree age.LocationRennes, Bretagne, Western FranceTaxonLittle‐dispersive, generalist oribatid mites (Acari) and highly dispersive, specialist gall wasps (Hymenoptera: Cynipidae) on oak (Quercus sp.) trees.MethodsWe tested the effects of tree and branch age, tree and branch habitat diversity, and tree phylogenetic isolation on per‐branch and per‐tree alpha‐diversity, and on within‐tree beta‐diversity of both taxonomic groups.ResultsFor gall wasps, no variable explained diversity patterns at any level. In contrast, for oribatid mites, we found that high phylogenetic isolation of trees and high branch age increased alpha‐diversity per tree and per branch (in young trees) as well as turnover among branches. High tree age decreased alpha‐diversity per branch (in phylogenetically isolated trees) and increased turnover among branches. Increasing habitat diversity increased alpha‐diversity per tree, but decreased alpha‐diversity per branch (in young trees).Main conclusionsFor mites, contrary to common expectation, we suggest that: (a) phylogenetically distant neighbours are a source of immigration of distinct species and (b) with the increase of tree age, species‐sorting results in a few species colonizing and dominating their preferred patches. In gall wasps, strict specialization on oaks, and efficient dispersal may render oak age or isolation unimportant. The positive relationship between isolation and within‐tree turnover is a new contribution to biogeography in general.

The oak gall wasps of Israel (Hymenoptera, Cynipidae, Cynipini)-diversity, distribution and life history.

Oak-galling wasps (Hymenoptera: Cynipidae, Cynipini) have been studied in Israel only superficially so far, despite interest in the Israeli fauna given its location at the southern edge of distribution range of the wasps and their oak hosts. We provide the first comprehensive review of the Israeli fauna of oak cynipids based on an extensive survey of the five naturally occurring oak species in Israel. We report 53 cynipid species, 37 of which are reported from Israel for the first time, 10 are currently known only from this country, and 9 are undescribed. With 27 species, Andricus is by far the biggest genus in Israel, followed by Cerroneuroterus, Neuroterus Plagiotrochus, and Pseudoneuroterus with 4 species each. Andricus megalucidus is synonymized under A. cecconii and Cerroneuroterus cerrifloralis is synonymized under C. lanuginosus. The sexual generations of Andricus cecconii, A. coriariformis, A. coriarius, A. miriami, Cerroneuroterus lanuginosus and Pseudoneuroterus macropterus are reported here for the first time. We recorded 65 gall types, with bud galls being the most common and conspicuous, followed by leaf and catkin galls. We provide illustrated keys for all Israeli species based on their galls, as well as information on host associations, life history, phenology and distribution patterns where available. 21 cynipid species are associated with Quercus ithaburensis and 27 species are associated with Q. boissieri, whereas Q. libani, Q. calliprinos and Q. cerris host much fewer species. Most species are currently known from either their sexual or asexual generation while only 24% of them are known from both. Mount Hermon was found to be an important hotspot, hosting about half of the Israeli cynipid fauna, and species richness generally declines from the Golan Heights southwards to the Judean Mountains. Cynipid species that are associated with oaks of sections Cerris and Quercus in Europe are mostly associated with the same sections in Israel.

Infestation potential of Dryocosmus kuriphilus Yasumatsu, 1951 (Hymenoptera: Cynipidae) in different natural populations of Castanea sativa Miller: an experimental ex situ test

The Asian chestnut gall wasp was accidentally introduced in Italy in 2002 and spread across Europe in the following years, becoming a serious threat for chestnut cultivations and rural economies of many countries. Exploring the variation in susceptibility of the host genetic resources is crucial to face the spreading of this pest. We used an experimental approach for testing the differential susceptibility within and between populations of European chestnut. For doing this, we compared both the infestation level and the rate of immune individuals in trees from populations of Spain, Italy, and Greece. We found that the level of infestation is not significantly different in the different provenances but that a higher rate of immune trees occur in Greece. Our results suggest that two different contingents of trees compose Greek populations: one major group of trees with the same susceptibility as the other populations and a second minor group of trees resistant to gall wasp infestation. Our data lay the basis for improving the currently adopted measures to mitigate gall wasp impacts.

Structural and Chemical Profiles of Myrcia splendens (Myrtaceae) Leaves Under the Influence of the Galling Nexothrips sp. (Thysanoptera).

Thysanoptera-induced galls commonly culminate in simple folding or rolling leaf gall morphotypes. Most of these galls are induced by members of the suborder Tubulifera, with only a few species of the suborder Terebrantia being reported as gall inducers. The Terebrantia, as most of the gall inducers, manipulates the host plant cellular communication system, and induces anatomical and biochemical changes in its host plant. In an effort to keep its homeostasis, the host plant reacts to the stimuli of the galling insect and triggers chemical signaling processes. In contrast to free-living herbivores, the signaling processes involving galling herbivores and their host plants are practically unknown. Current investigation was performed into two steps: first, we set the structural profile of non-galled and galled leaves, and looked forward to find potential alterations due to gall induction by an undescribed species of Nexothrips (suborder Terebrantia) on Myrcia splendens. Once oil glands had been altered in size and number, the second step was the investigation of the chemical profile of three tissue samples: (1) non-galled leaves of a control individual, (2) non-galled leaves of galled plants, and (3) galls. This third sample was divided into two groups: (3.1) galls from which the inducing thrips were manually removed and (3.2) galls macerated with the inducing thrips inside. The chemical profile was performed by gas chromatography/ mass spectrometric detector after headspace solid-phase extraction. The galling activity of the Nexothrips sp. on M. splendens culminates in mesophyll compactness interspersed to diminutive hypersensitive spots, development of air cavities, and the increase in size and number of the secretory glands. Seventy-two compounds were completely identified in the volatile profile of the three samples, from which, sesquiterpenes and aldehydes, pertaining to the “green leaf volatile” (GLVs) class, are the most abundant. The rare event of gall induction by a Terebrantia revealed discrete alterations toward leaf rolling, and indicated quantitative differences related to the plant bioactivity manipulated by the galling thrips. Also, the content of methyl salicylate has varied and has been considered a potential biomarker of plant resistance stimulated as a long-distance effect on M. splendens individuals.

Progress in chestnut breeding at the Institute of Fruit Tree and Tea Science, NARO, Japan

Organized, government-funded chestnut (Castanea crenata Sieb. et Zucc.) breeding, has been conducted at the Institute of Fruit Tree and Tea Science, NARO, in Japan since 1947. The initial objective was to develop cultivars that ripen in the early or mid-season, that excel in yield, nut size, and nut quality by intra-specific cross of Japanese chestnut or interspecific cross between Japanese and Chinese chestnut. Serious damage from the chestnut gall wasp (Dryocosmus kuriphilus Yasumatsu) (Dk) spread rapidly throughout Japan soon after the beginning of the program, and resistance to Dk was added as a goal of the program in 1952. By the early 1990s, six Japanese chestnut cultivars were released, including the currently leading cultivars, ‘Tanzawa’ (early-ripening), ‘Tsukuba’ (mid-ripening), and ‘Ishizuchi’ (late-ripening), that excel in yield, nut size, nut quality, and are resistant to Dk. With the successful establishment of Torymus sinensis, a parasitoid of Dk introduced from China, in the breeding field at NIFTS by the end of 1980s, the objective since the 1990s has been on improving nut quality by introducing genes from Chinese chestnut. ‘Shuuhou’ and ‘Mikuri’ have been released in this project. Furthermore, a simple method for evaluating the peeling pellicle ability was developed for breeding selection around the year 2000. Using this method, ‘Porotan,’ an easy peeling pellicle (EPP) cultivar of Japanese chestnut, was released in 2006. In addition, ‘Porosuke,’ which has EPP trait similar to ‘Porotan,’ and ripens one week earlier than ‘Porotan,’ was derived from the same cross as for ‘Porotan,’ and released in 2016. The current breeding objectives focus on breeding cultivars with good nut quality with EPP trait that ripen later than ‘Porotan’. To increase breeding efficiency, marker-assisted selection for easy peeling pellicle was performed in the 2010s. Furthermore, the development of DNA markers for other horticultural traits is currently in progress for future breeding.

Studies on release methods of Torymus sinensis (Hymenoptera: Torymidae), parasitoid of Dryocosmus kuriphilus Yasumatsu), into Turkey from Italy

The Asian Chestnut Gall Wasp (ACGW), Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), is a major pest of Castanea spp. in Asia, the USA and Europe. Based on successful biological control of the ACGW in Japan using Torymus sinensis Kamijo, work on the process of introduction of the parasite was performed as a sustainable approach for controlling the pest in the USA and in Italy. In Turkey the ACGW was found in Yalova, Gemlik, Bursa in 2014, and in 2017 ACGW extended from Yalova and Gemlik to new areas in the Marmara region including Orhangazi, Yildirim, Iznik, Mudanya, Inegol, Center of Bursa; Tepekoy, Kartepe, Kocaeli (Izmit); Samanli Mountains, Pamukova, Sakarya; Sile, Istanbul and Odemis, Izmir. Introduction programs of T. sinensis from Podova University, Italy to Turkey was started in May, 2014, and (a) a laboratory was built in Gacik, Yalova, (b) some parts of a chestnut tree were screened by fine cloth, (c) about 250 saplings were placed under chestnut trees for oviposition by ACGW in Summer, 2014. At the end of March, 2015, adults of T. sinensis and about 2000 galls of ACGW were brought to Yalova from Italy. The adults were fed on honey-drops and released to sites having newly developed buds with galls of ACGW. Due to cold weather in April 2015, good release sites could not be found. In October 2015 300 galls were collected and dissected for checking the success of the release. However, no larvae of T. sinensis were found. At the end of April 2016, some galls of ACGW were brought to Yalova again, and the hatching parasitoid adults were released on trees having newly developed buds. In September 2016 about 500 galls were collected from the release sites and dissected but only one larva was found. In August 2017, 130 galls of ACGW from the release sites were collected and dissected. T. sinensis larvae were obtained from 16% of the galls around Gacik village, Yalova.

Insect galls on Myrtaceae: richness and distribution in brazilian restingas

Abstract: Inventories in Brazilian restingas have been indicating that Myrtaceae are the plant family with the greatest richness of insect galls. A compilation of published data plus new records was elaborated with the aim of stablishing the number of gall morphotypes on this family in this physiognomy of the Atlantic Forest, producing a list of galled species, pointing out the predominant gall features, evaluating the taxonomical knowledge of the gallers, listing the associated fauna, and based on host plant endemisms and monophagy proposing the endemism of some galling species. Myrtaceae harbor 111 morphotypes of insect gall (about 75% induced by Cecidomyiidae, Diptera) on 25 host plant species, 15 endemic. Eugenia L. highlights as the plant genus with the highest number of galled species and gall richness. Leaves are the most galled organ. There is a predominance of globoid and fusiform shapes, green color, glabrous surface and a single internal chamber. The taxonomical data on gallers is deficient as many records have been presented at supraspecific levels. The associated fauna is rich and includes parasitoids, inquilines and predators. Twelve species of Cecidomyiidae, a single species of Curculionidae (Coleoptera) and one species of Eriococcidae (Hemiptera) have been associated exclusively with endemic hosts and then are proposed in the present study as endemic too. The geographical distribution of many galls and respective gallers are restricted to the State of Rio de Janeiro, where most inventories have been carried out. For the first time, Eugeniamyia dispar, previously known from a rural area of Rio Grande do Sul and restinga areas of São Paulo, is recorded in the State of Rio de Janeiro.

Distribution and dispersal of the invasive Asian chestnut gall wasp, Dryocosmus kuriphilus (Hymenoptera: Cynipidae), across the heterogeneous landscape of the Iberian Peninsula

Dryocosmus kuriphilus (Hymenoptera: Cynipidae), also known as the Asian chestnut gall wasp, is a non-native invasive species that has recently appeared in many regions of Europe, including the Iberian Peninsula. This species is an important pest of chestnut trees in several regions and is of concern for foresters in these areas. The results of this research revealed 14 different hotspots of infestation of D. kuriphilus and resulted in the development of models that predict the distribution of D. kuriphilus in Spain over the next 37 years (2019-2055). These results indicate a rapid spread in all Spanish chestnut forests and identify areas that are theoretically highly suitable and susceptible to colonization by this cynipid based on predictions of three different niche models. Although D. kuriphilus is able to induce galls on all chestnut trees, the models indicate that there are differences in the suitability of the different regions for this species. This differential suitability results in some areas having better environmental conditions than others for D. kuriphilus, which is a factor that should be taken into account in its management and biological control. This study of the current distribution, patterns of dispersal using GIS and potentially suitable areas for D. kuriphilus, using niche models will assist in the management and control of this pest in Spain.

Tracking the origin and dispersal of the Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera, Cynipidae) in Europe with molecular markers.

The Asian chestnut gall wasp, Dryocosmus kuriphilus, is an invasive pest causing significant damage to chestnut trees (Castanea spp., Fagaceae). Originating from China, it has recently invaded a wide range of regions in Europe and North America. Understanding the population genetic structure of important invasive pests is very useful for improving the knowledge concerning routes of expansion and colonizing capacity. Despite its economic importance, limited attention has been given to D. kuriphilus origin and spread, or to its genetic structure. In this study, D. kuriphilus populations sampled in eight European countries were screened using both mitochondrial (cytochrome c oxidase subunit 1; COI) and nuclear (internal transcribed spacer 2; ITS2) sequences, and Amplified Fragment Length Polymorphism (AFLP) markers. The molecular markers COI and ITS2 highlighted the presence of a single haplotype in all the studied populations. The recorded mitochondrial haplotype was identical to one of the most widespread haplotypes occurring in the native area (China). AFLP results indicated that D. kuriphilus individuals belong to two genetically distinct clusters without any further geographic clustering. These results suggest that D. kuriphilus populations in Europe could be the result of a single introduction of a Chinese founder population characterized by two genetically distinct lineages that subsequently spread rapidly across Europe. However, the possibility that populations originated from multiple introductions of the same Chinese mitochondrial haplotype cannot be excluded. The reported results provide useful information concerning this invasive species, potentially facilitating integrated pest management.

Short communication: Farmers’ opinions on chestnut (Castanea sativa Mill.) supply chain development strategies: A case study in Central Italy

Aim of the study: To identify the priority strategy for the strengthening of the chestnut supply chain through a participatory approach.Area of study: Mugello-Val di Sieve inTuscany region (Italy).Material and methods: The data were collected by administering a questionnaire to a sample of 126 chestnut growers (83 chestnut growers enrolled and 43 not enrolled in the Consortium of “Marronedel Mugello Protected Geographical Indication”) to identify the priority objectives and activities to develop the chestnut supply chain.Main results: It is necessary to develop a diversified strategy to stimulate the chestnut production and simultaneously enhance the marketing of the product in order to revive the chestnut cultivation inTuscany region. The main activities to be pursued are the implementation of silvicultural treatments of chestnut orchards and the integrated fight against chestnut gall wasp to increase the productivity and strengthen the “Marronedel Mugello Protected Geographical Indication” brand.Research highlights: Participatory approach is a fundamental instrument to define a common strategy to strengthen chestnut supply chain at local level.