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First records of Xylosandrus compactus (Coleoptera: Curculionidae, Scolytinae) in the Iberian Peninsula: An expanding alien species?



Xylosandrus compactus (Eichhoff) (Col.: Curculionidae, Scolytinae) is an ambrosia beetle species native to subtropical Eastern Asia, with great concern due to its high invasive ability. This species has invaded 54 countries worldwide, including 4 European countries (Italy, France, Greece, and Spain); it was detected in Mallorca (Balearic Islands, Spain) in October 2019. In the present work, X. compactus is recorded for the first time in the Iberian Peninsula (Girona province, NE Spain); specimens were collected in Banyoles (August 2020, attacking twigs of Laurus nobilis and Liquidambar styraciflua) and Platja d’Aro (October 2020, attacking twigs of L. nobilis). Up-to-date information is presented about its geographical distribution, host plants, biology, symptoms, associate damages, and the possible origin of this species in Europe.
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Accepted by L. Kirkendall: 14 Apr. 2021; published: 13 May 2021 161
Zootaxa 4970 (1): 161–170
Copyright © 2021 Magnolia Press Article
First records of Xylosandrus compactus (Coleoptera: Curculionidae, Scolytinae)
in the Iberian Peninsula: an expanding alien species?
1Plant Pathologist and Consulting Arborist, Tossa de Mar, Spain;
2Department of Biology (Zoology), University of the Balearic Islands, Spain;
3Department of Ecology, University of Alicante, Spain;
4Sanidad Agrícola Econex S.L., Santomera, Spain
*Corresponding author
Xylosandrus compactus (Eichhoff) (Col.: Curculionidae, Scolytinae) is an ambrosia beetle species native to subtropical
Eastern Asia, with great concern due to its high invasive ability. This species has invaded 54 countries worldwide,
including 4 European countries (Italy, France, Greece, and Spain); it was detected in Mallorca (Balearic Islands, Spain) in
October 2019. In the present work, X. compactus is recorded for the first time in the Iberian Peninsula (Girona province,
NE Spain); specimens were collected in Banyoles (August 2020, attacking twigs of Laurus nobilis and Liquidambar
styraciflua) and Platja d’Aro (October 2020, attacking twigs of L. nobilis). Up-to-date information is presented about its
geographical distribution, host plants, biology, symptoms, associate damages, and the possible origin of this species in
Key words: ambrosia beetles, Xyleborini, invasive species, alien species, Laurus nobilis, Liquidambar styraciflua,
Girona, Iberian Peninsula
Xylosandrus compactus (Eichhoff) (Col.: Curculionidae, Scolytinae) was detected for the first time in Europe in
winter 2010, in Portici and Napoli provinces (Campania, Italy), attacking twigs of Quercus ilex in a garden. In winter
2012, its presence was reported from Lucca province (Toscana), on Laurus nobilis, also in a garden. Just a couple of
years later, the insect was recorded attacking 26 host plant genera (Bosso et al. 2012, Francardi et al. 2012, Garonna
et al. 2012, Pennacchio et al. 2012). In summer 2016, a heavy attack on 13 ha of Mediterranean maquis in Circeo
National Park (Lazio, Italy) aroused considerable concern because the infestation affected characteristic vegetation,
such as Ceratonia siliqua, L. nobilis, Pistacia lentiscus, Q. ilex, Ruscus aculeatus and Viburnum tinus (Vannini et
al. 2017). In August 2016, damages due to attacks of X. compactus in big branches and trunks of C. siliqua were
described as unusual in Sicily (Gugliuzzo et al. 2019a, 2019b, 2020). Currently, this invasive species is present in
the Italian regions of Campania (since 2011), Toscana, Liguria (since 2012), Lazio (since 2013), Lombardia (since
2015), Sicilia (since 2016), and Emilia-Romagna (since 2018) (SAMFIX 2021, EPPO 2020).
In France, X. compactus was detected in summer 2015, in the departments of Alpes-Maritimes and Var, attacking
various ornamental plants, as Arbutus unedo, L. nobilis, Phillyrea sp. and Q. ilex (Chapin et al. 2016, EPPO
2017, Barnouin et al. 2020). Greece reported occurrences of X. compactus in July 2019 in the region of Argolida
(Peloponnese Peninsula), affecting mainly twigs of C. siliqua, but also in twigs of L. nobilis, Olea europaea, Cercis
siliquastrum, and Rhamnus sp. (Spanou et al. 2019). Spain was the last European country to report attacks of this
alien species when it was detected in October 2019 attacking twigs, branches, and trunk of one C. siliqua in a private
garden located in Mallorca (Balearic Islands) (Leza et al. 2020).
162 · Zootaxa 4970 (1) © 2021 Magnolia Press
So far, the affected hosts in Italy and France are included in 54 genera of forest, agricultural and ornamental
plants: Acacia, Acer, Alnus, Arbutus, Azalea, Caesalpina, Camellia, Cassia, Castanea, Casuarina, Celtis, Ceratonia,
Cercis, Cinnamomum, Citrus, Cornus, Corylus, Croton, Diospyros, Eucalyptus, Eugenia, Euonymus, Fagus, Ficus,
Fraxinus, Gardenia, Hibiscus, Hydrangea, Jasminum, Laurus, Liquidambar, Liriodendron, Magnolia, Malus, Melia,
Olea, Ostrya, Phyllyrea, Pistacia, Pittosporum, Platanus, Prunus, Punica, Quercus, Rhamnus, Rhododendron,
Ruscus, Salix, Sambucus, Tilia, Ulmus, Viburnum, Vitex, and Vitis (ANSES 2017, CABI 2020, EPPO 2020, SAMFIX
2021). However, the attacks in Italy, France, and Greece have shown a great preference for twigs of L. nobilis and
C. siliqua (Spanou et al. 2019, Gugliuzzo et al. 2020).
Until 2019, two species belonging to Xylosandrus were found in Spain: X. germanus (Blandford, 1894) and
X. crassiusculus (Motschulsky, 1866). Xylosandrus germanus was collected in Muxica (Bizkaia, Basque Country,
Northern Spain) using traps baited with conifer bark beetles attractants in July 2003 (López et al. 2007). In 2011 and
2012, some specimens of this species were collected in other localities of Eastern Basque Country (Goldarazena et
al. 2014), also captured in baited traps. The host plant of X. germanus remain unknown in Spain, although Pfeffer
(1994) cited attacks on Fagus sylvatica, Picea abies, Pinus densiflora, and P. pentaphylla from Western Europa,
while Schott (1994) reported infestations on Alnus spp., Betula spp., Carpinus betulus, Castanea sativa, Fraxinus
spp., Picea spp., Pinus sylvestris, Populus spp., Pseudotsuga menziesii, Quercus spp., Salix spp., and Ulmus glabra
from Alsace region (France). At present, no new locations for X. germanus have been reported in Spain; so the
actual widespread of this species remains not yet clear. In the future, this situation could be worse if X. germanus,
currently recorded in the Basque Country, attacks vegetation from the Mediterranean maquis; in summer 2018, it
was captured in the Circeo National Park (Lazio, Italy), sharing habitat with X. crassiusculus and X. compactus,
when years ago its attacks were focused in deciduous (Juglans spp., Fagus sylvatica, Castanea sativa, and Quercus
petraea) and conifer forests from Northern regions (Contarini et al. 2020).
On the other hand, the occurrence of X. crassiusculus in Spain is more recent. This invasive species was reported
from Benifaió (Valencia, Eastern Spain) in October 2016, attacking C. siliqua in a residential area (Gallego et al.
2017). Currently, and thanks to the tasks developed in the LiFE SAMFIX project, the species was reported from
other four municipalities near the city of Valencia: Alfarp, Monserrat, Picassent, and Náquera, attacking exclusively
C. siliqua. This restriction in host tree diversity in Spain contrasts with the high number of host species reported for
this ambrosia beetle: a total of 124 plant species, distributed in 46 families, whose at least 12 species occur in the
invaded area, highlighting forest genera (Alnus, Populus, Quercus, Salix), crops (Diospyros, Ficus, Malus, Olea,
Prunus) and ornamental genera (Acacia, Hibiscus, Magnolia). In France, attacks of X. crassiusculus have been
reported in C. siliqua, Cercis siliquastrum, Lagerstroemia indica, and Olea europaea, although this insect shows
high preferences for C. siliqua in the Mediterranean region (Barnouin et al. 2020).
X. compactus was reported for the first time in Spain in October 2019, after the detection of one carob tree
showing wilt, foliar necrosis and twig death, and a multitude of small holes with exudates, located in a private garden
of a residential area in Calvià (Mallorca, Balearic Islands) (Leza et al. 2020). In summer 2020, this species was
collected from an attacked C. siliqua in another private garden in Andratx, at 10 km from the first occurrence. Finally,
in summer–fall 2020, this species was recorded in Girona province (NE Spain), with data from several localities
and damages as reported in this work. Also they were reported to the competent authority of the Government, for
notification through the European Union Notification System for Plant Health Interceptions, EUROPHYT.
In July 2020, the gardener of a private property located in Banyoles (Girona, NE Spain; 42°06’ N, 2°45’ E) reported
sudden and generalized damages in a hedge composed by L. nobilis 5–7 m height, planted in 2008. Damages started
with foliar discoloration and twig wilts, evolving to twig dried, died, and broken. A small hole was observed in the
affected twigs, but no insects were found inside the gallery. As a caution measure, all declined twigs were pruned
and burned, and then a foliar spray treatment with deltamethrin was applied.
New affections on twigs were observed some weeks later. Samples of affected laurel twigs were collected in
3 August 2020 (Figure 1A) for visual inspection under stereomicroscope; the remaining twigs were placed inside
a special rearing cage. All collected insects were preserved in ethanol 70% until they were studied. A few days
later, in the same garden, some affected twigs from a Liquidambar styraciflua were also collected and preserved in
XYLOSANDRUS COMPACTUS IN IBERIA Zootaxa 4970 (1) © 2021 Magnolia Press · 163
the same way. One black 7-funnel trap baited with alpha-pinene and ethanol lures (Econex, Spain) was set up in a
corner of the garden, from August 27 to October 19; captures were collected on September 7 and October 19, and
all Scolytinae were preserved in ethanol 70% for identification.
On 1 October 2020, similar symptoms were detected in one specimen of L. nobilis (2 m height) in a forest
property in Platja d’Aro (Girona, Spain; 41°48’ N, 3°03’ E). Samples of affected twigs were collected and insects
found were preserved in ethanol 70%; the remaining affected twigs were pruned and burned. On 15 December. 2020,
some specimens of ornamental L. nobilis (3 m height, in pots) from Vidreres (Girona, Spain; 41°48’ N, 2°46’ E)
showed very similar symptoms and damages. Some affected twigs were collected, but no insects were found inside
the galleries. During November/December 2020, several private and public gardens, with specimens or hedges of L.
nobilis, were visited in Blanes (Girona, Spain; 41º40’ N, 2º48’ E) and Lloret de Mar (Girona, Spain; 41°41N, 2°50’
E). No symptoms of X. compactus attacks were observed in these gardens.
Taxonomic keys from Wood (1982), Dole & Cognato (2010) and Hulcr & Smith (2010) for genera, and from Faccoli
(2008), Nageleisen et al. (2015) and Gallego et al. (2017) for species were used to identify the Scolytinae captures;
comparison with specimens from our personal collections was also used. Number and source of collected specimens
are summarized in Table 1. We confirm that the insects collected in Banyoles, from affected twigs (directly or
by rearing cage emergence) and captured by the baited funnel trap, are X. compactus. A total of 80 adults were
collected from the rearing cage, with 69 females (1.6–1.9 mm) and 11 males (< 1 mm). From the affected twigs of
L. styraciflua, two adult females of X. compactus were collected. From Platja d’Aro, we collected 3 adult females
by direct collection in affected twigs. The laurels from Vidreres showed signs of attack by X. compactus but the
galleries were empty.
TABLE 1. Specimen number of X. compactus collected by locality and source.
Locality Coordinates Host plant Date Source Specimens/
Banyoles 42°06’ N, 2°45’ E Laurus nobilis 2020/Aug/03 Collection from twigs 5 ♀
2020/Oct/01 Rearing cage 69 ♀
11 ♂
Liquidambar styraciflua 2020/Aug/03 Collection from twigs 2 ♀
2020/Sep/17 Baited trap 6 ♀
2020/Oct/19 7 ♀
Platja d’Aro 41°48’ N, 3°03’ E Laurus nobilis 2020/Oct/01 Collection from twigs 3 ♀
Vidreres 41°48’ N, 2°46’ E Laurus nobilis 2020/Dec/15 Collection from twigs No specimens
found in galleries
The mean size of attacked twigs of L. nobilis from Banyoles was 6.4 mm diameter (Figure 1, Table 2), ranging
from 3 mm up to 20 mm. The attacks in L. styraciflua occurred in twigs with a mean diameter of 4.4 mm, ranged
from 3 mm up to 6 mm. In Platja d’Aro and Vidreres, both in L. nobilis, the size was similar, with 4.7 and 4.2 mm
respectively. In the most frequent affected twigs (4 mm diameter, 15–30 cm length) a single attack hole was only
observed, whereas in the biggest affected twigs (15–20 mm diameter, 50–90 cm length) a maximum of 9 holes was
counted, spaced from 3 up to 20 cm between them. The length of galleries ranged from 13 to 30 mm, although not
all attacks were completed; 35% of inspected holes showed no brood chamber or gallery inside. A dark coloration
envelops the internal tissues around the brood gallery (Figure 1 B, C, and E), showing the saprophytic activity of the
ambrosial fungi inoculated by X. compactus.
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TABLE 2. Size of attacked twigs. Std: standard deviation, Ø: diameter.
Locality Number and host plant Twigs Diameter (mean ± std, mm) Max Ø (mm) Min Ø (mm)
Banyoles 15 Laurus nobilis 51 6.39 ± 3.68 20 3
1 Liquidambar styraciflua 5 4.40 ± 1.14 6 3
Platja d’Aro 1 Laurus nobilis 7 4.71 ± 1.38 7 3
Vidreres 2 Laurus nobilis 5 4.20 ± 0.84 5 3
Four species of Scolytinae were collected in the baited trap set up in Banyoles during the sampled period (Table
3). In the first revision (17 September 2020), after 21 days, 6 X. compactus, 15 Xyleborinus saxesenii (Ratzeburg),
and 5 Cryphalini (possibly Hypothenemus eruditus Westwood, pending confirmation) were collected. In the second
revision (19 October 2020), 7 X. compactus, 7 X. saxesenii, 1 Xyleborus monographus (Fabricius), and 2 possible
H. eruditus were collected.
TABLE 3. Scolytinae collected in the baited trap set up in Banyoles (from 27 August 27 to 19 October 2020).
Species 17 Sep. 19 Oct. Total
Xylosandrus compactus 6 7 13
Xyleborinus saxesenii 15 7 23
Xyleborus monographus 0 1 1
Cryphalini (possibly Hypothenemus eruditus)5 2 7
Review of Biology and Ecology
X. compactus is a typical ambrosia beetle, whose larvae eat the symbiotic ambrosia fungi that grow covering the
gallery walls. These fungi spores have been transported into the thoracic micangium, located between pronote
and mesonote, by the founder females. This species breeds by haplodiploidy, with arrhenotokous parthenogenesis:
males are born from unfertilized (haploid) eggs and females from fertilized (diploid) eggs. The sex ratio is not
balanced, with 1 male per 9–10 females approximately (Hara & Beardsley 1979, Greco & Wright 2015). Males
have non-functional wings and usually live their whole life inside the gallery where born. Females are inseminated
by a brother male inside their brood gallery. Only the adult females are able to leave the natal host plant and find
new hosts, and emergence usual occurs in the afternoon hours (Hara & Beardsley 1979). Frequently, they attack
twigs and small branches (up to 20 mm diameter), but attacks on bigger branches or main trunks of C. siliqua have
been reported by Gugliuzzo et al. (2019a) from Sicily (Italy) and Leza et al. (2020) from Mallorca (Spain). Founder
females bore for oviposition until reaching the twig medulla, where they construct a brood gallery, shaped linearly,
more or less sinuous and centered in the twig, usually 10–30 mm length (up to 57 mm) and 0.5–6.5 mm width,
and forked from the entrance tunnel. But galleries have a different morphology when females bore in big branches
and trunks; in these situations, the galleries are bored in the xylem (Gugliuzzo et al. 2019b). Oviposition occurs
4–7 days after the female bores into a twig; eggs hatch 3–5 days after being laid (Greco & Wright 2015). Total egg
production per female ranges from 2 to 16 eggs (Hara & Beardsley 1979) and each gallery could produce between
10 and 40–60 new adults (Dixon et al. 2003, Gugliuzzo et al. 2019b). Larvae do not bore galleries, but live in the
brood gallery, eating the coating of ambrosia fungi.
Adult females overwinter inside the brood galleries and the new attacks start in spring. From Italy and Southern
France, X. compactus could be bivoltine or trivoltine, from April–May to the end of November (Pennacchio et al.
2012, Roques et al. 2019). The life cycle is developed in 28–31 days at laboratory conditions (Ngoan et al. 1976,
Hara & Beardsley 1979), but it could need up to 40 days depending on the physical and chemical conditions of the
host tree and the climatic conditions (Brader 1964). Adult females live between 39 and 58 days, whereas males have
a life span of 4–6 days (Hara & Beardsley 1979). The maximum flight and attacks would be in summer, from June
to early September (Ngoan et al. 1976), and Gugliuzzo et al. (2019a) referred the, possibly exceptional, ability to
migrate more than 8 km from an infested area to a healthy area within one year.
Meteorology determines the phenology of X. compactus. The flight after overwintering comes when daily
maximum temperatures remain stable for several days above 20ºC (Gugliuzzo et al. 2019a); similar behavior has
XYLOSANDRUS COMPACTUS IN IBERIA Zootaxa 4970 (1) © 2021 Magnolia Press · 165
been reported, using baited traps, for X. germanus (Reding et al. 2013). In Sicily, X. compactus could not stablish
permanent populations above 400 m altitude, where minimum winter temperatures are usually negative (Gugliuzzo
et al. 2019a). In Banyoles, during the 2016–2019 period (Table 4), the average temperature for the coldest months
(January and February) ranged between 1.2 to 1.3 ºC, with minimum values of -3.9 ºC in February 2018 and -5 ºC
in January 2017 (SMC 2020).
TABLE 4. Meteorological data from the station located in Banyoles (42º6’N, 2º47’ E, during the period
2016–2019; it shows (in ºC) annual mean temperature (AMeTem), minimum mean temperature (MMinT), and minimum
temperature (MinT) for January and February
Year AMeTem MMinT (Jan) MinT (Jan) MMinT (Feb) MinT (Feb)
2019 15,8 1,3 -3,5 3,9 -0,8
2018 15,6 4,5 -0,6 1,2 -3,9
2017 15,6 1,7 -5,0 5,8 -0,4
2016 15,4 4,9 -2,6 4,1 -1,2
X. compactus produces two kinds of damage on the host plant: mechanical by boring (Figure 1 D and E) and fungal
by the inoculation of the saprophytic fungi into the xylem (Figure 1 B, C, and E). Mechanical injuries are related
to the boring of the entrance hole (0.7–0.9 mm diameter; Figure 1 D) and the excavation of the brood gallery (up
to 30–57 mm long; Figure 1 E) along the twig medulla injure the vascular tissue, and the structural resistance is
also reduced. On the other hand, the ambrosia fungi cultivated inside the gallery act as pathogens to the host plant,
degrading the induced plant defenses and blocking the sap fluxes; moreover, the fungi can produce antagonistic
substances to avoid the development of other microorganisms inside the galleries (Greco & Wright 2015). Gugliuzzo
et al. (2020) reported in Italy 8 species of symbiotic fungi associated with X. compactus or its brood galleries,
usually Ambrosiella xylebori, A. macrospora, and Fusarium solani. Moreover, Bateman et al. (2016) and Vannini
et al. (2017) reported other fungi, as Acremonium, Clonostachys, Cytospora, Penicillium, and Xenoacremonium.
Furthermore, the fungal diseases associated with some Scolytinae and Platypodinae species are some of the most
important problems that have arisen in woody plants in recent decades (Ploetz et al. 2013).
We observed attacks of X. compactus in apparently healthy host plants, behavior also seen in other invasive
Xyleborini on non-native plant species (Atkinson et al., 1988; Henin & Verstein, 2004). Their attacks are more
frequent in the annual twigs (3–7 mm diameter), eliciting their death or breaking, though Gugliuzzo et al. (2019b)
found attacks in trunks and branches with maximum values of 85 cm and 36 cm, respectively. The first attack
evidence is white frass surrounding the entrance hole, followed by a turgor loss, wilt, and twig collapse, with a
progressive discoloration that ends in dryness and death of the twig from the entrance hole to the apex. This wilting
is already visible a few days after the attack, accordingly with Greco & Wright (2015) on Coffea. Other evidence
of the attack and associated damage is the cortical canker (Figure 1D) that has formed around the entrance hole
and along the brood gallery, between 1 and 21 cm length. The affected bark shows brown-purplish colorations, that
stand out from the typical brown drying (above the attacked area in the twig) and from the normal photosynthetic
green (below the attacked area). Debarking or cutting the twig on the affected area show xylem fibers with dark
colorations, due to the ambrosia fungi activity (Figure 1B, 1C and 1E). These fungi do not cause degradation of
the woody structure, but they are responsible for vascular collapse by plugging. This typology of symptoms and
damages observed are in agreement with those reported by Hara & Beardsley (1979), Chong et al. (2009), Greco &
Wright (2015), ANSES (2017), Gugliuzzo et al. (2019a, 2019b, 2020), Roques et al. (2019), Barnouin et al. (2020),
and CABI (2020).
166 · Zootaxa 4970 (1) © 2021 Magnolia Press
FIGURE 1. (A) Affected laurel (Laurus nobilis) twig in Banyoles (Girona); (B) cross section of an affected laurel twig;
(C) Females of X. compactus were found inside the brood gallery of a small laurel twig; (D) Detail of the cortical canker on
an affected laurel twig, near the entrance hole to the brood gallery; (E) brood gallery (3 cm long) established along the twig
Geographical distribution and possible origin of the invasion
These records about the presence for X. compactus during summer/fall 2020 in Banyoles, Platja d’Aro, and quite
possibly also in Vidreres, all of them in Girona province (NE Spain), are the first records for this species in Catalonia
(NE Spain) and also in the Iberian Peninsula; it must be remembered that the first record in Spain was reported
by Leza et al. (2020) from Mallorca (Balearic Islands) in October 2019. According to information received by the
gardener from Banyoles, the presence of a few affected twigs in the laurel hedge was already observed during summer
2019, but it did not generate too much concern. However, in summer 2020, the damages were more conspicuous and
generated alarm. This would indicate that X. compactus was present in this garden since spring 2019, at least.
The linear distance between Banyoles and Platja d’Aro is 42 km, while Platja d’Aro and Vidreres are separated
by 24 linear km. On the other hand, according to Barnouin et al. (2020), the French records closest to Girona are
located at Saint Tropez (captured in 2015 and 2017), at Bormes Les Mimosas (from 2018 and 2019), and at Saint
Raphaël (from 2019), all of them in Var Department (Figure 2); the distance between these French locations and
Banyoles is about 550 km. Probably, the introduction of X. compactus in the Iberian Peninsula is related to the
commerce of live ornamental plants. The chronology of European records for this species starts at Campania (Italy)
XYLOSANDRUS COMPACTUS IN IBERIA Zootaxa 4970 (1) © 2021 Magnolia Press · 167
in winter 2010 (Garona et al. 2012), followed by Alpes-Maritimes and Var (France) in summer 2015 (Chapin et al.
2016), Argolida (Greece) in July 2019 (Spanou et al. 2019), Mallorca (Spain) in October 2019 (Leza et al. 2020) and
we report Girona (NE Spain) in August 2020, although it is possible that the species was present in the area as early
as 2019. The first detection of X. compactus in France happened at Alpes-Maritimes Department, near the Italian
border of Piemonte and Liguria regions. Similarly, the congeneric X. crassiusculus, was first detected for Europe
in the Italian region of Toscana (Pennachio et al. 2003) and the first record from France was in Alpes-Maritimes,
near the Italian border (Roques et al. 2019). Possibly, both species arrived in France from Italy by ornamental plant
commerce, facilitated by the garden industry from Southern France (ANSES 2017, Gallego et al. 2017, Roques
et al. 2019). A very similar situation happened in Slovenia when X. crassiusculus was recorded in August 2017
at Podsabotin and Pračina, very close to the Italian border of the region of Friuli-Venecia Julia (Kavčič 2018).
Accordingly, we suspect that live ornamental plant commerce for public and private gardens of residential areas are
also related with the presence of X. compactus in Mallorca and Girona.
FIGURE 2. Reports of X. compactus in Spain and nearest locations in France: G1: Banyoles, G2: Platja d’Aro, G3: Vidreres
(Girona) and M1: Mallorca (Leza et al. 2020) from Spain; F1: Saint Tropez, F2: Bormes Les Mimosas, and F3: Saint Raphaël
(Var Department)
Simultaneous occurrence of several populations of Xylosandrus species in different European localities, after
the first detection in Italia in 2010, could be evidence of independent introduction events, either by infested host
plants directly from native Asian areas or by internal EU plant commerce from Italian plant producers. The European
Life SAMFIX project has, between their tasks, put in light the origin of these populations by molecular techniques,
currently in progress. New samples of insects from Girona will be taken in spring 2021 and will be sent to the
SAMFIX team for analysis. The risk of invasion for these species to new areas is very high because a simple adult
female could establish a permanent colony by inbreeding, and generate up to three annual generations that could
widespread quickly and silently across extended territories.
Potential distribution models of X. compactus proposed by Urvois et al. (2021) describe as suitable territories
the Mediterranean coasts and islands, except for Tunisia, Libya, Egypt, and Southeastern Iberian Peninsula. Authors
168 · Zootaxa 4970 (1) © 2021 Magnolia Press
also indicate that the Atlantic coast of the Iberian Peninsula, France, up to the UK are suitable areas, although
suitability decreases northwards and generally with distance from the coast. Accordingly, it is very likely that in
the next few years X. compactus will colonize new areas, expanding its distribution across suitable habitats in the
Iberian Peninsula. Kirkendall & Faccoli (2010) reported 19 alien Scolytinae species were apparently established in
Europe, 14 as potentially expanding (as X. crassiusculus), and 5 as probably currently spreading (as X. germanus).
Some years later, Rassati et al. (2016) reported 18 species in the Mediterranean Basin. Recently, Barnouin et al
(2020) listed 21 invasive species to France since XIX century, but more than half, 11 species, have been recently
introduced. Exotic and invasive Scolytinae pose a major threat to the forest, agricultural, and ornamental plant
resources around the world, and they can have serious economic and ecological consequences. A globalized trade,
aided by climate change, makes the transport of plant material colonized by these insects worldwide recognized as a
very important means of current biological invasions. So, implement new management and policy measures on live
plant commerce and early alert systems in the potential areas are indispensable to avoid future invasions.
We thank the people who, through citizen science, allowed the detection of the presence of X. compactus in some
locations from Girona, as well as for the help received and facilities they have provided us to work in their facilities:
Quim Llovera (Banyoles; Center de Jardineria 9 Jardí) and Toni Planas (Platja d’Aro; Parc d’Aventures Costa
Brava). Voucher specimens were deposited in authors’ private collections.
ANSES [Agence Nationale de Sécurité Sanitaire]. (2017) Évaluation du risque simplifiée sur Xylosandrus compactus (Eichhoff)
identifié en France métropolitaine. 68 pp. (accessed
11 January 2021)
Atkinson, T., Foltzm, J., Wilkinson, R. & Mizell, R. (1988) Gfranulate ambrosia beetle, Xylosandrus crassiusculus (Motschulsky)
(Insecta: Coleoptera: Curculionidae: Scolytinae). EDIS 2011. (accessed
11 January 2021)
Barnouin, T., Soldati, F., Roques, A., Faccoli, M., Kirkendall, L.R., Mouttet, R., Daubree, J.B. & Noblecourt, T. (2020) Bark
beetles and pinhole borers recently or newly introduced to France (Coleoptera: Curculionidae, Scolytinae and Platypodinae).
Zootaxa, 4877 (1), 51–74.
Bateman, C., Sigut, M., Skelton, J., Smith, K.E. & Hulcr, J. (2016) Fungal associates of the Xylosandrus compactus (Coleoptera:
Curculionidae, Scolytinae) are spatially segregated on the insect body. Environmental Entomology, 45, 883–890.
Bosso, L., Senatore, M., Varlese, R., Ruocco, M., Garonna, A.P., Bonanomi, G., Mazzoleni, S. & Cristinzio, G. (2012) Severe
outbreak of Fusarium solani on Quercus ilex vectored by Xylosandrus compactus. Journal of Plant Pathology, 94
(Supplement 4), S4.85–S4.105.
Brader, L. (1964) Etude de la relation entre le scolyte des rameaux du caféier, Xylosandrus compactus Eichh. (X. morstatti Hag.)
et sa plante-hôte. Mededlingen Landdbouwhogeschool, Wageningen, 64 (7), 1–109.
CABS [Center for Agriculture and Bioscience International]. (2020) Xylosandrus compactus (shot-hole borer). Available from: (accessed 11 January 2021)
Chapin, E., Mouttet R. & Chauvel, G. (2016) Xylosandrus compactus trouvé en France métropolitaine. Phytoma, 697, 10–12.
Chong, J.H., Reid, L. & Williamson, M. (2009) Distribution, host plants, and damage of the black twig borer, Xylosandrus
compactus (Eichhoff), in South Carolina. Journal of Agricultural and Urban Entomology, 26 (4), 199–208.
Contarini, M., Vannini, A., Giarruzzo, F., Faccoli, M., Morales-Rodriguez, C., Rossini, L. & Speranza, S. (2020). First record
of Xylosandrus germanus (Blandford) (Coleoptera: Curculionidae, Scolytinae) in the Mediterranean scrubland in Southern
Italy, and its co-presence with the co-generic species X. compactus (Eichhoff) and X. crassiusculus (Motschulsky). EPPO
Bulletin, 50, 311– 315.
Dixon, W.N., Woodruff, R.E. & Foltz, J.L. (2003) The black twig borer, Xylosandrus compactus (Eichhoff) (Coleoptera:
Curculionidae: Scolytinae). DPI Entomology Circular, 250, EENY-311.
XYLOSANDRUS COMPACTUS IN IBERIA Zootaxa 4970 (1) © 2021 Magnolia Press · 169
twig_borer.htm (accessed 11 January 2021)
Dole, S.A. & Cognato, A.I. (2010) Phylogenetic revision of Xylosandrus Reitter (Coleoptera: Curculionidae: Scolytinae:
Xyleborina). Proceeding of the California Academy of Sciences, 61 (10), 451–545.
EPPO [European and Mediterranean Plant Protection Organization] (2017) First report of Xylosandrus compactus in France. (accessed 11 January 2021)
EPPO [European and Mediterranean Plant Protection Organization] (2020) Xylosandrus compactus (XYLSCO). Available
from: (accessed on 11 January 2021)
Faccoli, M. (2008) First record of Xyleborus atratus Eichhoff from Europe, with an illustrated key to the European Xyleborini
(Col.: Curculionidae, Scolytinae). Zootaxa, 1772 (1), 55–62.
Francardi, V., Pennacchio, F., Santini, L., Rumine, P., Paoli, A., Navarra, A. & Musetti, N. (2012) prima segnalazione di
Xylosandrus compactus su Laurus nobilis in Toscana. Giornate Fitopatologiche, 13, 443–446.
Gallego, D., Lencina, J.L., Mas, H., Cever, J. & Faccoli, M. (2017) First record of the Granulate Ambrosia Beetle, Xylosandrus
crassiusculus (Coleoptera: Curculionidae, Scolytinae), in the Iberian Peninsula. Zootaxa, 4273 (3), 431–434.
Garonna, A.P., Dole, S.A., Saracino, A., Mazzoleni, S. & Cristinzio, G. (2012) First record of the black twig borer Xylosandrus
compactus (Eichhoff) (Coleoptera: Curculionidae, Scolytinae) from Europe. Zootaxa, 3251 (1), 64–68.
Goldarazena, A., Bright, D.E., Hishinuma, S.M., López, S. & Seybold, S.J. (2014) First record of Pityophthorus solus (Blackman,
1928) in Europe. EPPO Bulletin, 44, 65–69.
Greco, E.B. & Wright, M.G. (2015) Ecology, biology, and management of Xylosandrus compactus (Coleoptera: Curculionidae:
Scolytinae) with emphasis on coffee in Hawaii. Journal of Integrated Pest Management, 6 (1), 1–8.
Gugliuzzo, A., Criscione, G., Biondi, A., Aiello, D., Vitale, A. & Polizzi, G. (2020) Seasonal changes in population structure of
the ambrosia beetle Xylosandrus compactus and its associated fungi in a southern Mediterranean environment. PLoS ONE,
15 (9), e0239011, 1–13.
Gugliuzzo, A., Criscione, G., Siscaro, G., Russo, A. & Tropea Garzia, G. (2019a) First data on the flight activity and distribution
of the ambrosia beetle Xylosandrus compactus (Eichhoff) on carob trees in Sicily. EPPO Bulletin, 49 (2), 340–351.
Gugliuzzo, A., Criscione, G. & Tropea Garzia, G. (2019b) Unusual behavior of Xylosandrus compactus (Coleoptera: Scolytinae)
on Carob Trees in a Mediterranean Environment. Insects, 10, 82.
Hara, A.H. & Beardsley, J.W. (1979) The biology of the black twig borer, Xylosandrus compactus, in Hawaii. Proceedings,
Hawaiian Entomological Society, 13 (1), 55–70.
Henin, J. & Versteirt, V. (2004) Abundance and distribution of Xylosandrus germanus (Blandford, 1894) (Coleoptera: Scolytidae)
in Belgium: new observations and an attempt to outline its range. Journal of Pest Science, 77, 57–63.
Hulcr, J. & Smith, S.M. (2010) Xyleborini ambrosia beetles. An identification tool to the World Genera. Available from: http:// (accessed on 11 January 2021)
Kavčič, A. (2018) First record of the Asian ambrosia beetle, Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae,
Scolytinae), in Slovenia. Zootaxa, 4483 (1), 191–193.
Kirkendall, L.R. & Faccoli, M. (2010) Bark beetles and pinhole borers (Curculionidae, Scolytinae, Platypodinae) alien to
Europe. ZooKeys, 56, 227–251.
Leza, M., Núñez, L., Riba-Flinch, J.M., Comparini, C., Roca, A. & Gallego, D. (2020) First record of the black twig borer,
Xylosandrus compactus (Coleoptera, Curculionidae, Scolytinae), in Spain. Zootaxa, 4767 (2), 345–350.
López, S., Iturrondobeitia, J.C. & Goldarazena, A. (2007) Primera cita de la Península Ibérica de Gnathotrichus materiarius
(Fitch, 1858) y Xylosandrus germanus (Blandford, 1894) (Coleoptera: Scolytinae). Boletín de la Sociedad Entomológica
Aragonesa, 40, 527–532.
Nageleisen, L., Bouget, C. & Noblecourt, T. (2015) Les scolytes du genre Xylosandrus en France (Coleoptera Curculionidae
Scolytinae). L’Entomologiste, 71 (4), 267–271.
Ngoan, N.D., Wilkinson, R.C., Short, D.E., Moses, C.S. & Mangold, J.R. (1976) Biology of an introduced ambrosia beetle,
Xylosandrus compactus, in Florida. Annals of the Entomological Society of America, 69 (5), 872–876.
Pennachio, F., Roversi, P., Francardi, V. & Gatti, E. (2003) Xylosandrus crassiusculus (Motschulsky), a bark beetle knew to
Europe. Redia, 86, 77–80.
Pennacchio, F., Santini, L. & Francardi, V. (2012) Bioecological notes on Xylosandrus compactus (Eichhoff) (Coleoptera
170 · Zootaxa 4970 (1) © 2021 Magnolia Press
Curculionidae Scolytinae), a species recently recorded into Italy. Redia, 95, 67–77.
Pfeffer, A. (1994) Zentral- und Westpaläarktische Borken- und Kernkäfer (Coleoptera: Scolytidae Platypodidae). Entomologica
Basiliensia, 17, 5–310.
Ploetz, R.C., Hulcr, J., Wingfield, M.J. & Wilhelm de Beer, Z. (2013) Destructive Tree Diseases Associated with Ambrosia and
Bark Beetles, Black Swan Events in Tree Pathology? Plant Disease, 95 (7), 856–872.
Rassati, D., Lieutier, F. & Faccoli, M. (2016) Alien wood-boring beetles in Mediterranean regions. In: Paine, T.D. & Lieutier, F.
(Eds.), Insects and diseases of Mediterranean forest systems. Springer International Publishing, Cham, pp. 293–327.
Reding, M.E., Ranger, C.M., Oliver, J.B. & Schultz, P.B. (2013) Monitoring attack and flight activity of Xylosandrus spp.
(Coleoptera: Curculionidae: Scolytinae): the influence of temperature on activity. Journal of Economic Entomology, 106,
Roques, A., Bellanger, R., Daubrée, J.B., Ducatillion, C., Urvois, T. & Auger-Rozenberg, M.A. (2019) Les scolytes exotiques:
une menace pour le maquis; l’expansion rapide de Xylosandrus crassiusculus et X. compactus associée à leur polyphagia
nécessitent de mieux connaître ces ravageurs de ligneux. Phytoma, 727, 16–20.
SAMFIX (2021) SAving Mediterranean Forests from Invasions of Xylosandrus beetles and associated pathogenic fungi (Life17
NAT/IT/000609, Started 2018–Jul). Available from: (accessed 11 January 2021)
Schott, C. (1994) Catalogue et Atlas des Coléoptères d’Alsace. Tome 6 Scolytidae. Societe Alsacienne d’Entomologie, Musée
Zoologique de l’Université et de la Ville de Strasbourg, Strasbourg, 85 pp.
SMC-Servei Meteorològic de Catalunya (2020) Anuari de dades meteorològiques per les estacions XEMA i XOM; Banyoles
(Girona). (accessed 11 January 2021)
Spanou, K., Marathianou, M., Gouma, M., Dimou, D., Nikoletos, L., Milonas, P.G. & Papachristos, D.P. (2019) First record of
black twig borer Xylosandrus compactus (Coleoptera: Curculionidae) in Greece. 18th Panhellenic Entomological Congress,
KOMOTINI 15‐17/X/2019, Abstract, pp. 77.
Urvois, T., Auger-Rozenberg, M.A, Roques, A., Rossi, J.P. & Kerdelhue, C. (2021) Climate change impact on the potential
geographical distribution of two invading Xylosandrus ambrosia beetles. Scientific Reports, 11 (1339). [published online]
Vannini, A., Contarini, M., Faccoli, M., Della Valle, M., Rodriguez, C.M., Mazzetto, T., Guarneri, D., Vettraino, A.M. &
Speranza, S. (2017) First report of the ambrosia beetle Xylosandrus compactus and associated fungi in the Mediterranean
maquis in Italy, and new host–pest associations. EPPO Bulletin, 47, 1–4.
Wood, S.L. (1982) The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic
monograph. Great Basin Naturalist Memoirs, 6, 1–1359.
... This species was previously detected in other European countries: Italy, France, Monaco and Greece (CABI, 2021a;EPPO, 2021b). In August 2020, X. compactus was recorded for the first time on the Iberian Peninsula (Banyoles, Girona province, North-East Spain), attacking twigs of Laurus nobilis (Riba-Flinch et al., 2021). Moreover, attacks of X. compactus were also reported on carob trees and hazelnuts (Corylus avellana) in Salou (Tarragona), 180 km south of Banyoles (EPPO, 2021a). ...
... The introduction of this species in North America and Europe is most likely associated with trading and the movement of infested timber, wood products or untreated solid wood packaging (Bruge, 1995;Inward, 2018), as well as with the movement and commerce of infested live ornamental/ agricultural plants (Björklund & Boberg, 2017). These were also the most likely pathways for the introduction of X. crassiusculus into the EU (EFSA et al., 2020) and X. compactus into Spain (Riba-Flinch et al., 2021). ...
... Several publications have shown evidence of the spread of X. germanus, X. crassiusculus and X. compactus in recent years in Europe, especially in France and Italy (Barnouin et al., 2020;CABI, 2021a;Contarini et al., 2020;DACC, 2021;Dzurenko et al., 2021;EPPO, 2021b;Faccoli, 2021;Gallego et al., 2020;Gugliuzzo et al., 2021;Riba-Flinch et al., 2021;Roques et al., 2019). The European Life SAMFIX project (www.lifes ...
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The black stem borer Xylosandrus germanus (Blandford, 1894) (Coleoptera: Curculionidae: Scolytinae) is a species native to Eastern Asia that has invaded 24 countries worldwide, including 21 European countries, the USA, Canada and New Zealand. On the Iberian Peninsula it was recorded for the first time in traps placed in the Basque Country (Northern Spain) in 2003, but its host plants were unknown. In the present work, three populations of X. germanus are recorded in the east of Spain in Girona, Tarragona and Valencia provinces (Automomous Community of Catalonia, and Valencia, respectively). Specimens were collected in traps and on host plants, showing a wider distribution range now including the east and northeast of the Iberian Peninsula. Infested carob trees (Ceratonia siliqua) were found in agricultural and urban green areas in Tarragona. Ceratonia siliqua is therefore reported here as a new host of X. germanus.
... Durante el verano de 2020 se localizó otro ejemplar de algarrobo atacado en otro jardín privado en Andratx, también en Mallorca. La primera cita para la península ibérica se registró en un jardín de Banyoles, Platja d'Aro y Vidreres (Girona), en verano de 2020, tanto atacando planta hospedadora como en trampas cebadas con alfa-pineno y etanol (Riba et al., 2021). También fue encontrado en otoño de 2020 atacando C. siliqua y Corylus avellana en plantación, en Vila-seca (Tarragona) Al igual que las otras dos especies, X. compactus también es muy polífaga. ...
... Este tipo de ataque fue reportado por primera vez por Gugliuzzo et al., (2019) en Sicilia en 2019, y fue considerado como un comportamiento inusual. En Girona y Tarragona, en cambio, los ataques se registran sobre ramillos y ramas de hasta 70 mm de diámetro (Riba et al., 2021). crassiusculus. ...
... Las invasiones de las tres especies del género Xylosandrus en España se ajustan muy bien a este patrón de invasión silenciosa, ya que han escapado a los sistemas de vigilancia y ha sido la casualidad y la ciencia ciudadana lo que ha permitido la detección de estas especies (Tabla 1). X. germanus fue detectado mediante trampas no selectivas o cuya diana era otra especie (López et al., 2007;Goldarazena et al., 2014); profesionales de la jardinería fueron quienes alertaron de la presencia de daños inusuales en jardines privados, que resultaron en la localización de X. compactus de las dos ubicaciones mallorquinas y la ubicación de Girona (Leza et al., 2020, Riba et al., 2021. En cambio, la localización de X. compactus en Vila-seca fue consecuencia del aviso por parte de cultivadores de algarrobo al servicio de Sanidad Vegetal de la Gerenalitat de Catalunya. ...
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Ciertos grupos biológicos están predispuestos para invadir nuevos territorios, facilitado por las actividades humanas. Los Xyleborini (Coleoptera, Curculionidae, Scolytinae) reúnen características que les dotan de capacidad invasiva: i) haplodiploidía, una única hembra puede generar poblaciones viables; ii) polifagia, no se alimentan del hospedador vegetal, sino de hongos que trasportan en micangios y que cultivan en las galerías que perforan (xilomicetofagia), y iii) perforan xilema vivo, siendo muy difíciles de detectar al no causar un decaimiento tan rápido como los floemofagos. Entre estos Xyleborini se encuentra el género Xylosandrus, con unas 54 especies. Tres de estas, Xylosandrus germanus, X. crassiusculus y X. compactus, han invadido numerosos países, incluido España. Se presentan datos actualizados sobre la distribución conocida de estas tres especies en España. X. germanus fue citado por primera vez en 2003 y se distribuye por el País Vasco, y posiblemente territorios colindantes. En 2021 esta especie ha sido encontrada atacando algarrobo en Vila-seca, (Tarragona) y capturado en trampas en Gandía, (Valencia) y Platja d’Aro, (Girona) X. crassiusculus fue detectado en 2016 y en la actualidad se encuentra restringido a dos focos próximos a la ciudad de Valencia, atacando casi exclusivamente algarrobo. X. compactus ha sido detectado recientemente, en 2019 y 2020 en el oeste de Mallorca, sobre algarrobo de jardinería, y en 2020 en Banyoles (Girona) atacando a laurel y Liquidambar de jardinería, en Vila-seca (Tarragona) atacando algarrobo y avellano, en Platja d’Aro y Vidreres (Girona) sobre laurel.
... C. limon (L.), Cornus sanguinea Thunb., Coryllus avellana, Eucalyptus spp., Evonymus spp., Fagus spp., Ficus spp., Fraxinus ornus L., Hibiscus spp., Gardenia spp., L. nobilis, Liquidambar styraciflua L., Liriodendron tulipifera L., Magnolia spp., Morus alba L., Olea europea L., Phillyrea spp., Pistacia lentiscus L. Pittosporum spp., Platanus spp., Prunus laurocerasus L., Punica granatum L., Q. ilex, Q. robur Asso, Rhamnus sp., Ostrya spp., Rhododendron spp., Ruscus aculeatus L., Tilia spp., Ulmus spp., Viburnum tinus L., and Vitis spp. (FITOLAB 2011;Pennacchio et al. 2012;Vannini et al. 2017;Spanou et al. 2019;Leza et al. 2020;Faccoli 2021;Riba-Flinch et al. 2021). In addition, Riba-Flinch et al. (2021) reported that the affected hosts in Italy and France are included in 54 genera of forest, agricultural, and ornamental plants. ...
... (FITOLAB 2011;Pennacchio et al. 2012;Vannini et al. 2017;Spanou et al. 2019;Leza et al. 2020;Faccoli 2021;Riba-Flinch et al. 2021). In addition, Riba-Flinch et al. (2021) reported that the affected hosts in Italy and France are included in 54 genera of forest, agricultural, and ornamental plants. ...
... The MaxEnt algorithm can be used to model the spread of invasive species around the world. For the invasive ambrosia beetle Xylosandrus compactus Eichhoff, 1876, which occurs in southern Europe (Pennacchio et al., 2012;Barnouin et al., 2020;Leza et al., 2020;Riba-Flinch et al., 2021), with the continuation of average climatic values from 1970 to 2000, X. compactus is predicted to find suitable ecological conditions for development in southern Moravia (which is the warmest region of the Czech Republic) by 2050 (Urvois et al., 2021). ...
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Invasive bark beetles pose a threat to native biodiversity and to functional ecosystems and the economic productivity of forests, parks, and orchards. In the Czech Republic, there are six species of invasive ambrosia and bark beetles with a stable natural population, and it can be assumed that other invasive species that will be found. In the Czech Republic, there are no guidelines or methods for the early detection of invasive ambrosia and bark beetles. We propose monitoring at a total of 24 locations considering the following: (i) monitoring approaches used in other countries; (ii) identified entrance gates of invasive ambrosia and bark beetles found in the Czech Republic; (iii) presumed invasive species that occur in surrounding countries and are expanding their range; (iv) substances attractive to all the above mentioned species; (v) commonly available traps; and (vi) minimization of operating costs. Most of the chosen locations are located on the state borders and in river valleys, which are probably the entrance gates to the Czech Republic for invasive ambrosia and bark beetles. In addition, two large timber warehouses where international trade takes place, all international airports and three botanical gardens with tropical greenhouses were selected. Three Theysohn or Ecotrap impact traps should be installed every year at all locations. Traps should be baited with ethanol and exposed from mid-April to the end of July and should be checked every 2 weeks.
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Resumen: Después de la primera cita de Xylosandrus compactus (Eichhoff, 1876) (Coleoptera: Curculionidae: Scolytinae) para la península ibérica en Banyoles (Girona) en 2020 y sobre Laurus nobilis ornamentales, a finales del 2022 se reportan ataques en 25 municipios de 6 comarcas de las provincias de Girona y Barcelona. La lista de plantas afectadas en Cataluña asciende ya a un total de 38 especies de 30 géneros, con una gran preferencia para Laurus nobilis y Ceratonia siliqua, seguido de Cercis siliquastrum, Magnolia grandiflora y Arbutus unedo. Aunque la mayoría de estos ataques han sido sobre brotes anuales, también se han observado daños sobre ramaje de calibre diverso y tronco. Cabe destacar la presencia de ataques de X. compactus sobre especies forestales y sobre vegetación de ribera y de barrancos, y que podrían comportar daños significativos y consecuencias ecológicas sobre el laurel, el cual también está sufriendo ataques de tigre (Stephanitis lauri Rietchel, 2014 [Hemiptera: Tingidae]), cochinilla (Protopulvinaria pyriformis [Cockerell, 1894] [Hemiptera: Coccidae]) y psila (Trioza alacris Flor, 1861 [Hemiptera: Triozidae]). Abstract: After the first record of Xylosandrus compactus (Eichhoff, 1876) (Coleoptera: Curculionidae: Scolytinae) for the Iberian Peninsula in Banyoles (Girona province) in 2020 with attacks on ornamental Laurus nobilis, at the end of 2022 attacks in 25 municipalities in 6 regions of the provinces of Girona and Barcelona are reported. The list of affected host plants in Catalonia amounts to a total of 38 species from 30 genera, with a high preference for Laurus nobilis and Ceratonia siliqua, followed by Cercis siliquastrum, Magnolia grandiflora and Arbutus unedo. Although most of these attacks have been on annual shoots, damages on branches of various diameters and trunks have also been observed. It is worth noting the presence of attacks by X. compactus on forest species and vegetation from riparian and ravines habitats; it could cause significant damage and ecological consequences for the bay laurel, which is also suffering attacks and damages from lace bug (Stephanitis lauri Rietchel, 2014 [Hemiptera: Tingidae]), soft scale (Protopulvinaria pyriformis [Cockerell, 1894] [Hemiptera: Coccidae]) and psyllid (Trioza alacris Flor, 1861 [Hemiptera: Triozidae]).
Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae, Scolytinae) is a worldwide invasive species that causes huge economic loss and environmental damage in many countries. Traditional morphological characteristics make it hard to identify scolytines due to their tiny size. Besides, the intercepted insect samples are incomplete, and the limitation of insect (larvae and pupae) morphology makes morphological identification more difficult. The majority of the damage is caused by adults and fungi that serve as nutrition for their larvae. They destroy plant trunks, branches, and twigs, affecting plant transport tissues in both weak and healthy plants. An accurate, efficient, and economical molecular identification technique for X. compactus not restricted by professional taxonomic knowledge is necessary. In the present study, a molecular identification tool based on the mitochondrial DNA gene, cytochrome C oxidase subunit I (COI) was developed. A species-specific COI (SS-COI) PCR assay was designed to identify X. compactus regardless of the developmental stage. Twelve scolytines commonly found in eastern China, namely Xylosandrus compactus, X. crassiusculus, X. discolor, X. germanus, X. borealis, X. amputates, X. eupatorii, X. mancus, Xyleborinus saxesenii, Euwallacea interjectus, E. fornicatus, and Acanthotomicus suncei, were included in the study. Additionally, specimens of X. compactus from 17 different areas in China, as well as a specimen collected from the United Stated, were also analyzed. Results demonstrated the accuracy and high efficiency of the assay, regardless of the developmental stage or the type of specimen. These features provide a good application prospect for fundamental departments and can be used to prevent the harmful consequences of the spread of X. compactus.
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Xylosandrus compactus, a xylomycetophagous bark beetle species, is predominantly polyphagous and primarily phytophagous. Xylosandrus compactus is the second Xylosandrus species reported in Turkey, and it is known for its severe damage to economically valuable plants in its spreading areas worldwide. The present research, in which we also detected different hosts after the first record in Turkey, was carried out between July (2022) and February (2023). During the field studies, wilted and dried twigs with insect entrance holes were cut and brought to the laboratory for examination. As a result of our research, a total of 25 new species (Acer negundo, A. pseudoplatanus, Aesculus x carnea, A. hippocastanum, Buxus sempervirens, Carpinus betulus, Castanea sativa, Cornus sanguinea, Corylus avellana, Elaeagnus angustifolia, Juglans regia, Laburnum anagyroidis, Liriodendron tulipifera, Malus domestica, M. floribunda, Mespilus germanica, Prunus laurocerasus, Punica granatum, Quercus castaneifolia, Q. robur, Q. rubra, Tilia tomentosa, Smilax excelsa, Ulmus minor, Viburnum opulus) have been added to the host list of Xylosandrus compactus and the number of host plants raised to 32.
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The invasive ambrosia beetle Xylosandrus germanus (Curculionidae: Scolytinae: Xyleborini) is recorded for the first time infesting wine grapes in Italy. The type of the attack is illustrated and the possible causes of the onset of the infestation are discussed. Furthermore, given the continuously increasing number of alien wood-borer beetles introduced worldwide, we provide and discuss the updated world checklist of Scolytinae attacking Vitaceae, and Vitis sp. in particular.
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Xylosandrus compactus and X. crassiusculus are two polyphagous ambrosia beetles originating from Asia and invasive in circumtropical regions worldwide. Both species were recently reported in Italy and further invaded several other European countries in the following years. We used the MaxEnt algorithm to estimate the suitable areas worldwide for both species under the current climate. We also made future projections for years 2050 and 2070 using 11 different General Circulation Models, for 4 Representative Concentration Pathways (2.6, 4.5, 6.0 and 8.5). Our analyses showed that X. compactus has not been reported in all potentially suitable areas yet. Its current distribution in Europe is localised, whereas our results predicted that most of the periphery of the Mediterranean Sea and most of the Atlantic coast of France could be suitable. Outside Europe, our results also predicted Central America, all islands in Southeast Asia and some Oceanian coasts as suitable. Even though our results when modelling its potential distribution under future climates were more variable, the models predicted an increase in suitability poleward and more uncertainty in the circumtropical regions. For X. crassiusculus, the same method only yielded poor results, and the models thus could not be used for predictions. We discuss here these results and propose advice about risk prevention and invasion management of both species.
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We present an annotated list of 11 Scolytinae and Platypodinae species newly or recently introduced to France. Four species are recorded for the first time as interceptions: Euplatypus hintzi (Schaufuss), Euplatypus parallelus (Fabricius), Xyleborus affinis Eichhoff and Xyleborus ferrugineus (Fabricius). Two are possibly naturalised: Xyleborus bispinatus Eichhoff and Cryphalus dilutus Eichhoff, while Cyclorhipidion distinguendum (Eggers) and Xyloterinus politus (Say) are confirmed as species newly established in Europe. Moreover, an unidentified species of Amasa Lea, collected previously in Spain, is recorded for the first time in France: Amasa sp. near truncata (Erichson). We point out that literature references to Amasa truncata as an invasive species in New Zealand and South America are incorrect, as the photographs of these non-native populations do not match the holotype of A. truncata. For each species we have updated its global distribution, detailed all French records, and summarized biology, ecology, host trees and potential risks as pests.
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Exotic ambrosia beetles are increasing in Europe due to global trade and global warming. Among these xylomycetophagous insects, Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae) is a serious threat for several Mediterranean host plants. Carob trees growing in Sicily (Italy) have been extensively attacked by beetles leading to rapid tree decline. Although X. compactus has been found in Europe for several years, most aspects of its ecology are still unknown. We thus studied the population structure and dynamics of X. compac-tus, together with its twig size preference during a sampling of infested carob trees in south east Sicily. In addition, fungi associated with insects or galleries were isolated and characterized. The results showed that, in this newly-colonized environment and host plant, adult X. compactus overwinters inside twigs and starts to fly and reproduce in mid spring, completing five generations before overwintering in late fall. The mean diameter of carob twigs infested by the beetle varied significantly over the seasons, with the insect tending to infest larger twigs as season progresses. The mean number of adults/gallery was 19.21, ranging from 6 to 28. The minimum temperature significantly affected the overwintering adult mortality. Ambrosiella xylebori and Fusarium solani were the main symbionts associated with the pest in this study. Acremonium sp. was instead recorded for the first time in Europe inside X. compactus galleries. Several other fungi species were also found for the first time in association with X. compactus. Our findings provide useful insights into the sustainable management of this noxious pest.
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In the Circeo National Park (Italy), a survey assessed the occurrence of the ambrosia beetle Xylosandrus germanus in addition to the conspecifics X. compactus and X. crassiusculus . This is the first report in Europe of the co‐presence of three Xylosandrus species, in an evergreen Mediterranean maquis dominated by holm oaks ( Quercus ilex L.). Although no damage caused by X. germanus has been observed, the richness of plant species in the Circeo National Park may allow the establishment of this highly polyphagous ambrosia beetle, possibly endangering this native ecosystem. The dominance in the associated fungal community of Ambrosiella grosmanniae and Fusarium spp. reflects a stable symbiotic relationship of these taxa with X. germanus .
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We present the first record for Spain of the black twig borer, Xylosandrus compactus, an ambrosia beetle of Asian origin, collected from an infested carob tree located in Calvià (Majorca, Balearic Islands, Spain). X. compactus is included in the EPPO Alert List, and it has been recently reported causing damages in a Mediterranean maquis ecosystem in Italy and Southern France. Here, we discuss about the first steps of management of this Invasive Alien species (IAS), the eradication plan and the hypothesis of the path of introduction in this Western Mediterranean island.
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Xyleborus atratus Eichhoff, an ambrosia beetle of Asian origin, is reported for the first time from Europe, based on a series of females collected in northern Italy in April 2007 and 2008 in funnel traps baited with ethanol. A diagnosis of the species and a revised key to the genera and species of Xyleborini occurring in Europe is presented. An explanation is suggested for the large number of recent introductions of exotic ambrosia beetles into Europe.
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Xylosandrus compactus (Eichhoff), commonly known as the black twig borer, was reported in Sicily (Italy) at the end of 2016, infesting Carob tree (Ceratonia siliqua L.) twigs, large branches, and trunks. Previous research indicated that X. compactus attacks only small twigs and branches, not large branches and tree trunks. This unusual behavior was monitored through the two following years in five sites in Ragusa province (Sicily, Italy). For each of the monitored sites, the diameter of the infested trunks and branches was recorded. Samples of branches and trunks presenting galleries were removed from the trees and analyzed in the laboratory. Xylosandrus compactus occurred on branches of all monitored trees, while the percentage of infested trunks of carob trees ranged from 60% to 80%. Inside the infested galleries, all biological stages of X. compactus were found. Infestations were also recorded on trunks and branches with diameters greater than 80 cm and 30 cm, respectively. The mean number of X. compactus specimens inside the galleries was recorded and gallery shape was described. Unordinary behaviors, like the one described here for the first time, can affect the current efficiency of management recommendations.
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The Granulate Ambrosia Beetle Xylosandrus crassiusculus, an alien species of Asian origin, was recorded for first time in the Iberian Peninsula. Many specimens were collected in October 2016 in the Valencia region (Spain) from infested carob trees. The species is included in the EPPO Alert List as causing serious damage in many Mediterranean regions. A key for the morphological identification of the Xylosandrus species occurring in Europe is also reported.
The factors influencing the entry and the spread of the black twig borer, Xylosandrus compactus (Eichhoff), in the Mediterranean environment have not yet been characterized. Following its first report in Sicily (southern Italy) in 2016, and due to the high level of damage it causes on one of its host plants ( Ceratonia siliqua L.), the flight activity of the pest was studied there. Monitoring was performed from spring 2017 to summer 2018 by exposing red cross‐shaped sticky traps combined with ethanol‐baited bottle traps. The three monitored sites were selected at different altitudes, representing the southern Mediterranean environment where the carob tree is widely present. The results showed that the pest populations are influenced by climatic factors. In particular, the first adults were caught when the maximum daily temperatures were stably higher than 20°C over several continuous days. Xylosandrus compactus occurred widely in the monitored territory and was continuously caught from spring to autumn. Furthermore, the traps used proved to be effective for intercepting the spring flight of the overwintering females. Moreover, the ability of the beetle to spread from a new infested area was also studied. It seems that the pest can spread more than 8 km from the last infested site of the previous flying season. It was not present above altitudes of 400 m in the conditions of the present study. This study represents the first step to better understand the behaviour of X. compactus in a newly colonized environment.
Xylosandrus crassiusculus (Coleoptera: Curculionidae, Scolytinae), with the common name the Asian ambrosia beetle or the granulate ambrosia beetle, originates in tropical and subtropical regions of eastern Asia. It is one of the most widespread wood-boring beetles and among these one of the most successful invaders (IPPC 2017). Outside its native habitat, the species is present in Africa (Wood & Bright 1992, Atkinson et al. 2000), in Australia (IPPC 2017), on the Pacific Islands (Beaver 1976), in the Americas (Atkinson 1988, Rabaglia et al. 2006, Flechtmann & Atkinson 2016, Landi et al. 2017) and in Europe (Pennacchio et al. 2003, Nageleisen et al. 2015, Gallego et al. 2016, Francardi et al. 2017).