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Azalea sawfly Nematus lipovskyi (Hymenoptera: Tenthredinidae), a new invasive species in Europe

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􀀃A new non-native species of sawfly Nematus lipovskyi Smith, 1974, previously known only in the USA, has heavily infested the ornamental azalea plant, Rhododendron molle, in the Czech Republic since at least 2010. The data on this species in the USA is briefly summarized. The larva and hitherto unknown male are newly described and illustrated. The life cycle is described based on field observations and the rearing of larvae collected in Charles University Botanic Garden in Prague. The host plants are listed and include the first record of a European species of azalea (Rhododendron luteum). The current distribution of Nematus lipovskyi in the Czech Republic based on the results of a preliminary monitoring project carried out by Charles University in Prague and the State Phytosanitary Administration is presented. The pathways of its introduction and spread, potential phytosanitary measures and its effect on the environment are briefly discussed.􀀑
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180
INTRODUCTION
The recent increase in the number of non-native species
of insects being introduced into Europe and their spread,
caused by worldwide human travel and trade, has result-
ed in serious problems throughout Europe, including the
Czech Republic. The most well-known examples of in-
vasive species include Cameraria ohridella Deschka &
Dimic, 1986 (Lepidoptera: Gracillariidae) and Harmonia
axyridis (Pallas, 1773) (Coleoptera: Coccinellidae), which
have had a negative effect on horse chestnut trees and the
diversity of local ladybird beetle faunas in the countries in-
vaded, respectively (Percival et al., 2011; Vilcinskas et al.,
5HFHQWO\WKH(DVW$VLDQVDZÀ\Aproceros leucopo-
da (Takeuchi, 1939) was introduced into Europe, which re-
sulted in outbreaks of this species and extensive defoliation
of elms in some parts of South and Central Europe (Blank
et al., 2010; Zandigiacomo et al., 2011; Seljak, 2012). Here
ZH UHSRUW DQRWKHU QRQQDWLYH VSHFLHV RI VDZÀ\ WKDW KDV
DSSHDUHGLQ(XURSHWKH$]DOHDVDZÀ\Nematus lipovskyi
Smith, 1974, which locally has become a pest of the orna-
mental azalea, Rhododendron molle, planted in parks and
gardens in certain locations in the Czech Republic.
Nematus lipovskyi is a member of the subfamily Nemati-
QDH7HQWKUHGLQLGDHDJURXSRIVDZÀLHVZLWKRYHU
species worldwide, of which about 550 occur in Europe
(Taeger et al., 2010; Taeger & Blank, 2011). The mostly
free-feeding larvae are usually monophagous or oligopha-
gous on various trees, herbaceous plants and grasses.
Nematus lipovskyi was described by Smith (1974) from
females reared from swamp azalea (Rhododendron molle).
The type series consists of specimens from the following
US states: Massachusetts, New Jersey, Pennsylvania, Ala-
bama, Maryland, Maine, New Hampshire and Virginia. Ac-
cording to some references (Johnson & Lyon, 1991; Boggs
et al., 2000; Cranshaw, 2004) it is apparent that N. lipov skyi
is widely distributed in the eastern part of the USA, where
it is a familiar pest of ornamental deciduous species of Rho-
dodendron (Azalea), both native (such as R. calendulace-
um and R. viscosum) and introduced (R. molle from China
and Japan). In addition to Nematus lipovskyi, there are two
RWKHUVSHFLHVRIVDZÀ\LQWKH86$DVVRFLDWHGZLWKD]DOHD
plants: Amauronematus azaleae Marlatt, 1896 (Tenthredi-
nidae, Nematinae) and Arge azaleae Smith, 1989. Outside
WKH86$WKHUHLVRQO\DSDVVLQJUHIHUHQFHWRDQXQVSHFL¿HG
UKRGRGHQGURQVDZÀ\ EHORQJLQJ WRWKH IDPLO\ $UJLGDH LQ
Quanzhou City in China (Zheng & Chen, 2011), possibly
Arge similis (Snellen van Vollenhoven, 1860) (D. Smith,
pers. comm.). In the Czech Republic, Nematus lipov skyi
ZDV¿UVWUHFRUGHGLQEDVHGRQODUYDHH[WHQVLYHO\GH-
foliating Rhododendron molle in Charles University Bo-
tanic Garden in Prague. Due to a failure to rear the species,
LWZDVQRWUHOLDEO\LGHQWL¿HGXQWLOZKHQIHPDOHVZHUH
collected directly from rhododendron shrubs. In spite of
the larvae being relatively well-known, they have not pre-
viously been described and the males are unknown. There-
fore, both larvae and males are described here. In addition,
the current status of this species’ occurrence in the Czech
Republic based on the preliminary results of a preliminary
monitoring project carried out by the Charles University
Faculty of Science and the State Phytosanitary Administra-
tion (hereafter abbreviated as SPA) (Kapitola & Pekárko-
vá, 2013), is also presented. Furthermore, an account of the
bionomics of the local population of N. lipovskyi in Charles
8QLYHUVLW\%RWDQLF*DUGHQEDVHGRQ¿HOGREVHUYDWLRQVLV
also presented.
Eur. J. Entomol. 112 (1): 180–186, 2015
doi: 10.14411/eje.2015.018
ISSN 1210-5759 (print), 1802-8829 (online)
$]DOHDVDZÀ\Nematus lipovskyi+\PHQRSWHUD7HQWKUHGLQLGDH
DQHZLQYDVLYHVSHFLHVLQ(XURSH
JAN MACEK1 and PETR ŠÍPEK2
1௘'HSDUWPHQWRI(QWRPRORJ\1DWLRQDO0XVHXP.XQUDWLFH&=3UDKD&]HFK5HSXEOLFHPDLOmacjan@seznam.cz
2௘'HSDUWPHQWRI=RRORJ\)DFXOW\RI6FLHQFH&KDUOHV8QLYHUVLW\LQ3UDJXH&=3UDKD&]HFK5HSXEOLF
e-mail: sipekpetr80@gmail.com
.H\ZRUGVHymenoptera, Tenthredinidae, Nematus lipovskyi, Czech Republic, Europe, Rhododendron molle, R. luteum, invasive
species, morphology, bionomics, dispersal, pest species, horticulture
$EVWUDFW$QHZQRQQDWLYHVSHFLHVRIVDZÀ\Nematus lipovskyi Smith, 1974, previously known only in the USA, has heavily infested
the ornamental azalea plant, Rhododendron molle, in the Czech Republic since at least 2010. The data on this species in the USA is
EULHÀ\VXPPDUL]HG7KHODUYDDQGKLWKHUWRXQNQRZQPDOH DUHQHZO\GHVFULEHG DQGLOOXVWUDWHG7KH OLIHF\FOHLVGHVFULEHGEDVHGRQ
¿HOGREVHUYDWLRQVDQGWKHUHDULQJRIODUYDHFROOHFWHGLQ&KDUOHV8QLYHUVLW\%RWDQLF*DUGHQLQ3UDJXH7KHKRVWSODQWVDUHOLVWHGDQG
LQFOXGHWKH¿UVWUHFRUGRID(XURSHDQVSHFLHVRID]DOHDRhododendron luteum). The current distribution of Nematus lipovskyi in the
Czech Republic based on the results of a preliminary monitoring project carried out by Charles University in Prague and the State
Phytosanitary Administration is presented. The pathways of its introduction and spread, potential phytosanitary measures and its effect
RQWKHHQYLURQPHQWDUHEULHÀ\GLVFXVVHG
181
VSHFLHVZDVLGHQWL¿HGEDVHGRQ6PLWK¶VRULJLQDOGHVFULS-
tion. Field observations on the occurrence, oviposition behaviour
and level of damage caused by N. lipovskyi in Charles University
Botanic Garden were carried out by P. Šípek, who also took pho-
tographs of living specimens and the damage to the host plants.
Voucher specimens of both larvae and adults are deposited in the
insect collection at the Department of Entomology, National Mu-
seum, Prague; photographs are kept in Charles University Fac-
ulty of Science photograph gallery archive. The distribution map
(Fig. 4) was prepared from a draft map produced by SPA and
vector maps were downloaded from http://www.vecteezy.com/.
For light microscopy of the collected material (Figs 1–2) a series
0$7(5,$/$1'0(7+2'6
Samples of both adults and larvae (approx. 200 adults and 300
larvae) were collected from Charles University Botanic Garden
by one of the authors (PŠ), other samples of larvae were collected
at various locations throughout the Czech Republic by SPA in-
spectors (Kapitola & Pekárková, 2013). All material was submit-
WHGIRULGHQWL¿FDWLRQWRWKH(QWRPRORJLFDO'HSDUWPHQWRIWKH1D-
tional Museum in Prague. Distribution records are supplemented
with the respective faunistic grid number of the grid mapping sys-
tem of Central Europe (Ehrendorfer & Hamann, 1965; Pruner &
Míka, 1996). Taxonomic analysis was carried out using standard
entomological procedures for morphological diagnostics. This
Fig. 1. Nematus lipovskyi Smith, 1974, adult: a – female; b – male; c – ovipositor (lateral view); d – female abdomen (apical part,
dorsal view); e – lancet; f – penis valva. Scales: a, b – 5 mm; c, e, f – 0.3 mm; d – 12 mm.
182
of digital photographs was taken with an OLYMPUS DP camera
attached to an OLYMPUS SZX microscope. Composite images
with an extended depth of focus were created using the software
CombineZP and subsequently processed using other graphic pro-
grammes. The other images were taken with various standard
cameras. Morphological terminology used in the descriptions fol-
lows that of Viitasaari (2002).
5(68/76
Nematus lipovskyi 6PLWK
'HVFULSWLRQ $GXOW. Female (Fig. 1) was described by
Smith (1974) who also provided illustrations of the ovi-
positor sheath and lancet.
Male (Fig. 1): Length: 4.5–5 mm. Yellow-orange with
DQWHQQDHODUJH VSRW RQIURQWDO ¿HOGH[WHQGLQJ DV IDUDV
frontal pit and antennal socket), mesonotum and metano-
tum, dorsal and ventral part of mesopleuron, metapleuron,
proximal half of metacoxa, all terga except narrow stripes
on posterior margins and laterotergites, black.
Head. Alutaceous, with short, dense, pale pubescence;
in dorsal view transverse with temples parallel and round-
ed posteriorly; postocellar area slightly convex, twice as
wide as long, lateral postocellar furrows short, slightly
depressed, parallel; OOL : OOC : POL = 1 : 1 : 0.9; fron-
WDO¿HOGÀDW ZLWK LQGLVWLQFWIURQWDOULGJHIURQWDOSLWGHHS
QDUURZO\WULDQJXODUFO\SHXVÀDWVKLQ\ZLWKGHHSO\HPDU-
ginate anterior margin; malar space as long as diameter of
anterior ocellus; antenna distinctly longer than head and
WKRUD[ FRPELQHG UHODWLYH OHQJWKV RI ÀDJHOORPHUHV ±
about 0.95 : 1 : 1 : 0.75 : 0.70 : 0.63 : 0.63.
Thorax. Median mesoscutal lobe shiny in middle with
shallow scattered punctures, alutaceous anteriorly; median
mesoscutellar groove arc-shaped and narrow; lateral meso-
scutal lobes covered with dense shallow punctures with
alutaceous interspaces; mesoscutellum slightly convex,
VKLQ\ZLWK¿QHVSDUVHSXQFWXUHVPHVRSOHXURQZLWKGHQVH
¿QH SXQFWXUHV PHVRVFXWHOODU DSSHQGDJH ZLWK GLVWLQFW
deep punctures; metascutellum smooth, shiny; legs with
metatarsus a little shorter than metatibia, metabasitarsus as
long as three following tarsomeres combined; inner tibial
spur of metatibia a little shorter than half of metabasitarsus,
claws with small inner tooth.
Abdomen. Cylindrical with apex rounded posteriorly,
WHUJD¿QHO\DOXWDFHRXVVWHUQDVKLQ\ZLWKVFDWWHUHGSXQFWD-
tion; genitalia as in Fig. 1.
9DULDELOLW\ 1R VLJQL¿FDQW YDULDWLRQ LQ WKH PDWHULDO
available.
/DVWLQVWDU IHHGLQJ ODUYD (Figs 2, 3c). Body length
9–10 mm. Head greyish-green; entire head covered with
VFDWWHUHG¿QHKRPRJHQHRXVSXEHVFHQFHFO\SHXVZLWKIRXU
setae, labrum with four setae; mandibles with one seta,
stipes without setae, palpifer with three setae; second seg-
ment of maxillary palps with one small seta; prementum
with two very short setae, second segment of labial palp
with one short seta; body in upper part green, in lower part
paler; cuticle smooth and shiny, spiracles narrow; all tho-
racic segments with a pair of large dorsal lobes with long
setae, trochanter shorter than femur, with scattered long
hair-like setae, tibia longer than tarsus with ten hair-like se-
tae; abdominal segments with six annulets, annulets three,
¿YHDQGVL[YHU\QDUURZVWULSOLNHWLJKWO\DVVRFLDWHGZLWK
SUHFHGLQJ DQQXOHW ¿UVW VHFRQG DQG IRXUWK DQQXOL ODUJH
convex dorsally; subspiracular, second postspiracular and
surpedal lobes prominent with ring-like spots surrounding
setal bases; second annulet with six, fourth annulet with
HLJKWORQJKDLUOLNHVHWDH¿UVWSRVWVSLUDFXODUOREHZLWKRQH
second postspiracular lobe with two long cylindrical setae,
ninth abdominal segment with two short conical protuber-
ances, suranal and subanal lobes with long hair-like setae,
basal parts of prolegs with black spots, covered with scat-
tered long hair-like setae.*
%LRQRPLFV This species is univoltine. Adults were
observed from the end of April to the beginning of May
2013, with a peak between 22–24 April. However the
ÀLJKWSHULRGPLJKWEHLQÀXHQFHGE\WHPSHUDWXUHDQGPD\
be prolonged from mid-April to mid-May. The tempera-
WXUHVGXULQJ SHDNÀLJKW GD\V ZHUHDV IROORZVPLQLPXP
temperature 5°C, maximum day temperature 22°C, mean
WHPSHUDWXUH&$QRQ\PRXV7KHPDLQÀLJKW
SHULRGFRLQFLGHGZLWKWKHEXUVWLQJRIWKHÀRUDOEXGVRIWKH
KRVWSODQWV'XULQJ WKH ÀLJKW SHULRGPDVVVZDUPLQJZDV
REVHUYHGZLWKVHYHUDOKXQGUHGVRI IHPDOHVÀ\LQJDURXQG
WKHEXVKHV7KHÀ\LQJLQGLYLGXDOVZHUHQRWDWWUDFWHGWR\HO-
low pitfall traps (on the ground) or yellow sticky plates in
WKHEUDQFKHV6XUSULVLQJO\QRPDOHVZHUHFDXJKWLQÀLJKW
but some 10 male individuals were collected attached to
the sticky covers of R. obtusum buds a few days later. Dur-
LQJWKH ÀLJKW SHULRGIHPDOHV ZHUH REVHUYHGOD\LQJHJJV
in the central vein of young leaves in bursting buds (Fig.
3). Oviposition was preceded by thorough inspection of
the bud. Young larvae hatched within 7–10 days of ovi-
 7KHKDELWXVRIWKHODVWIHHGLQJODUYDOLQVWDUGLIIHUVVLJQL¿FDQWO\
from the preceding instars, which are characterized by the presen-
ce of prominent black setiferous pinnacles on the dorsal parts of
thorax and abdomen.
Fig. 2. Nematus lipovskyi Smith, 1974, last feeding larval in-
star preserved in alcohol (discolored): a – habitus (lateral view);
b – head + thorax (lateral view); c – head + thorax (dorsal view);
d – anal segment with caudal protuberances (dorsal view). Scales:
a – 5 mm; b, c – 4 mm; d – 1 mm.
183
position. The feeding tracks on the leaves have a charac-
teristic appearance. Larvae of the last feeding instar were
recorded from mid-May to the end of May. Larvae start
feeding on the leaf margin and subsequently completely
consume the whole leaf except for the thick central vein.
7KH¿UVWYLVLEOHGDPDJHRFFXUVDSSUR[LPDWHO\WZRZHHNV
after oviposition and if there is a severe infestation the host
plants are completely defoliated within two to three weeks
RIODUYDOHPHUJHQFH)LJ7KH¿QDOQRQIHHGLQJODUYDO
instar (eonymph) descends and burrows into the soil where
LWKLEHUQDWHVDVDSUHSXSD LQVLGH D ¿UP FRFRRQ 3XSDWLRQ
occurs after hibernation and depending on the temperature
adults emerge between mid-April and mid-May.
In the USA, Smith (1974) listed Rhododendron viscosum
and R. molle as food plants; Johnson & Lyon (1991) added
R. calendulaceum. In the Czech Republic, in addition to R.
molle two other species of Rhododendron were recorded as
host plants for N. lipovskyi, the European R. luteum Sweet
and the R. obtusum hybrid “Ledikanense” from Japan.
Host plants, their origin and the parts consumed are listed
in Table 1. Larvae fed on both the leaves and blossoms of
R. molle and R. luteum. 2QO\WKH ÀRZHUV RIR. obtusum
were consumed, suggesting that R. obtusum may only be
an accidental host plant.
'LVWULEXWLRQ7KLVVSHFLHVZDV¿UVWFROOHFWHGLQLQ
Massachusetts, USA, but it was not until 1974 that it was
formally described by Smith (1974). The USA is so far the
only country in which N. lipovskyi naturally occurs and is
distributed there in the eastern states from Maine in the
QRUWKWR$ODEDPDLQWKHVRXWKXQYHUL¿HGUHFRUGVH[LVWIRU
Wisconsin (Fig. 4) (D. Smith, pers. comm.). In Europe, it
ZDV¿UVWUHFRUGHGLQLQWKH&KDUOHV8QLYHUVLW\%RWDQ-
ic Garden, Prague (Czech Republic) based on larvae feed-
ing on Rhododendron molle and R. luteum. Flying adults
were not recorded there until 2013. Additional data were
obtained either by inspectors of the SPA and other pub-
lic services during 2013 (Kapitola & Pekárková, 2013) or
came from various gardening enthusiasts (Fig. 4). Reports
from private gardening enthusiasts were only taken into
DFFRXQWLIWKH\ZHUHVXI¿FLHQWO\UHOLDEOHHJZLWKDSKR-
Fig. 3. Nematus lipovskyi Smith, 1974: a – ovipositing female; b – damage to R. luteum; c – alive larvae feeding on R. luteum (lateral
view).

tograph), but did provide feedback on how long the spe-
cies had been causing visible damage in a particular local-
LW\$OOUHFRUGVZHUHFRQ¿QHGWR%RKHPLDPRVWZHUHIRU
Central Bohemia (34) and Prague (18), but the species was
DOVRUHFRUGHGLQWKHUHJLRQVRI+UDGHF.UiORYp3O]HĖ
(2), Pardubice (1), Liberec (1), Ústí (1) and South Bohemia
(2). Except for the above mentioned records of adults in
the Botanic Garden, all records are based exclusively on
¿QGLQJODUYDHDQGIHHGLQJWUDFNVRQIRRGSODQWV7KLVVSH-
cies appears to disperse relatively slowly; with only two
records of N. lipovskyi in 2010, an additional two in 2011
and nine new localities in 2012. Currently the species is
recorded in at least 60 localities.
'LVWULEXWLRQUHFRUGV
5HFRUGVVLQFH Bohemia centr., Praha, Botanic Garden
of the Faculty of Science, Charles University in Prague, Prague.
190 m a.s.l. Pavlata J., Macek P. & Šípek lgt. (5952); Bohemia
FHQWU.RĜHQLFH QHDU .ROtQ  PDVO+REORYiSHUVFRPP
(6059); 5HFRUGV VLQFH  Bohemia centr., Vrané nad Vlta-
vou, 196 m a.s.l., Tejnická, pers. com. (6052); Bohemia centr.,
Senohraby, 363 m a.s.l., Tóbiková, pers. com. (6164). 5HFRUGV
VLQFH %RKHPLDFHQWU3UDKDĆiEOLFHPDVO0DOi
pers. com. (5852); Bohemia centr., Újezd nad Lesy, 255 m a.s.l.,
&DUYDQRYi SHUV FRP  %RKHPLD FHQWU3UĤKRQLFH 
m a.s.l., Gabrielová, pers. com. (5953, 6053); Bohemia centr.,
%ĜH]tPDVO2SSORYiSHUVFRP%RKHPLDFHQWU
'REĜLFKRYLFHPDVO5XQGRYi SHUV FRP  %RKH-
PLDFHQWU2NURXKOR=DKRĜDQ\YLOODJHPDVO/LãNDSHUV
FRP%RKHPLD FHQWU0XNDĜRYPDVO+UDGHFNi
SHUV FRP  %RKHPLD FHQWU 0QtãHN SRG %UG\  P
DVO+DQþLORYiSHUVFRP%RKHPLDFHQWUâWČFKRYLFH
PDVO-HĜiENRYiSHUVFRP 5HFRUGVVLQFH
%RKHPLDERU'ČþtQPDVO.DSLWROD3HNiUNRYi
 %RKHPLD ERUýHVNi /tSD  PDVO.DSLWR-
OD 3HNiUNRYi  %RKHPLD RU -LþtQ  PDVO
.DSLWROD 3HNiUNRYi %RKHPLDFHQWU0ČOQtN
215 m a.s.l. (Kapitola & Pekárková, 2013) (5652, 5653); Bohe-
mia or., Kopidlno, 219 m a.s.l. (Kapitola & Pekárková, 2013)
(5657); Bohemia centr., Dolany u Prahy, 192 m a.s.l. (Kapitola
& Pekárková, 2013) (5752); Bohemia centr., Statenice, 258
m a.s.l. (Kapitola & Pekárková, 2013) (5851); Bohemia centr.,
6YUN\QČPDVO.DSLWROD3HNiUNRYi%R-
KHPLDFHQWU3UDKDPDVO-XUiãNRYiSHUVFRP
%RKHPLD FHQWU 5R]WRN\ X 3UDK\  P DVO 9OþNRYi SHUV
com. (5852); Bohemia centr., Zdiby u Prahy, 295 m a.s.l., Seidl,
SHUVFRP%RKHPLDFHQWU+XVLQHFXěHåHPDVO
(Kapitola & Pekárková, 2013) (5852); Bohemia centr., Praha 7
±6WURPRYND  P DVO 9RGYiĜNDSHUV FRP
%RKHPLDFHQWU3UDKD±9LQRĜPDVOěHKiNRYiSHUVFRP
 %RKHPLD FHQWU3UDKD  9\VRþDQ\  P DVO .UiO
pers. com. (5853, 5952, 5953); Bohemia centr., Káraný, 173 m
a.s.l., Lohrová, pers. com. (5854); Bohemia centr., Velký Osek
Fig. 4. Distribution of N. lipovskyi in the United States and the Czech Republic. Asterisk – records since 2010; full circles – records
since 2011; open circles – records since 2012; grey circles – records since 2013; grey triangles – records since 2013 (SPA data).
TABLE 1. Host plants of N. lipovskyi.
Host plant species Country of origin of host plant /
observation of infestation Consumed parts Source
Rhododendron molle (Blume) G. Don
and hybrids China, Japan / USA, Czech Rep. /HDYHVÀRZHUV Smith, 1974; pers. observ.
Rhododendron calendulaceum (Michx.) Torr. USA / USA /HDYHVÀRZHUV" Johnson & Lyon (1991)
Rhododendron viscosum (L.) Torr. USA / USA /HDYHVÀRZHUV" Smith, 1974
Rhododendron luteum Sweet East and Central Europe,
West Asia / Czech Rep. /HDYHVÀRZHUV Pers. observ.
Rhododendron × obtusum “Ledikanense” Japan / Czech Rep. Flowers Pers. observ.
185
± 2VHþHN  P DVO .RXERYi SHUV FRP  %RKHPLD
centr., Praha 4, Bráník, 199 m a.s.l., Votýpka, pers. com. (5952);
%RKHPLDFHQWU3UDKD  %ĜHYQRYPDVO 6YRERGD SHUV
FRP%RKHPLDFHQWU3UDKD  6WĜHãRYLFH  P DVO
%XULiQHNSHUVFRP%RKHPLDFHQWU3UDKD 5X]\QČ
274 m a.s.l., Vinkler, pers. com. (5952); Bohemia centr., Praha 5,
Smíchov, 196 m a.s.l., Havová, pers. com. (5952); Bohemia cen-
WU3UDKD.UþPDVO1ČPFRYiSHUVFRP%RKH-
PLDFHQWU3UDKDâWČUERKRO\PDVO)ROWêQSHUVFRP
%RKHPLDFHQWU3UDKD3RþHUQLFH PDVO9HEHU
SHUVFRP%RKHPLDFHQWU3UDKD8KĜtQČYHVPDVO
$QGHUORYiSHUVFRP %RKHPLD FHQWU3UDKD.ĜHVOLFH
282 m a.s.l., Fiala, pers. com. (5953); Bohemia centr., Pacov u
ětþDQPDVO9RMiþNRYiSHUVFRP%RKHPLDRU
&KRFHĖP DVO 3DYFR SHUV FRP GRXEWIXO
UHFRUG%RKHPLDFHQWU7ĜHERWRYPDVO%DãWDSHUVFRP
%RKHPLDFHQWU3UDKD5DGRWtQPDVOýHUQêSHUV
FRP%RKHPLDFHQWUětþDQ\PDVO0DFKiþNRYi
pers. com. (6053, 6054); Bohemia centr., Kamenice, 368 m a.s.l.,
Šefrna. pers. com. (6053, 6153); Bohemia centr., Jevany, 380
m a.s.l., (Kapitola & Pekárková, 2013) (6054); Bohemia centr.,
ýDNRYLFHPDVO.DSLWROD3HNiUNRYi%R-
hemia centr., Samechov, 383 m a.s.l., Vávrová, pers. com. (6155);
%RKHPLDRFF3O]HĖPDVO.DSLWROD3HNiUNRYi
  %RKHPLD FHQWU /KRWND X 'REĜtãH  P DVO
.DSLWROD3HNiUNRYi%RKHPLDFHQWU%HQHãRY
u Prahy, 360 m a.s.l., (Kapitola & Pekárková, 2013) (6254); Bo-
KHPLDRFFâĢiKODY\PDVO.DSLWROD3HNiUNRYi
  %RKHPLD FHQWU 5RåPLWiO SRG 7ĜHPãtQHP 
m a.s.l., (Kapitola & Pekárková, 2013) (6349); Bohemia centr.,
.DPêNQDG 9OWDYRXPDVO 9HþHĜRYiSHUVFRP
Bohemia mer., Blatná, 440 m a.s.l., Šípek lgt. (6549); Bohemia
PHU2OHãQiPDVODQRQ\PRXVSHUVFRPXQYHUL-
¿HGUHFRUG
',6&866,21
Based on the known distribution of N. lipovskyi it would
be easy to assume that the species was introduced into the
Czech Republic from the USA with ornamental azalea
plants used in horticulture. However this assumption may
QRW EH MXVWL¿HG DV WKH IDFW WKDW N. lipovskyi was origi-
nally detected in the USA may not mean that the species
originated from there. In fact, there are several species of
VDZÀ\GHVFULEHGIURPWKHLUVHFRQGDU\SRSXODWLRQVRXWVLGH
their native ranges. For example, Nematus tibialis New-
man, 1837 feeding on false acacia (Robinia pseudoacacia
Linnaeus, 1753), which is native to North America, was
described from Europe (Smith, 1979); another example
is Pristiphora angulata Lindqvist, 1974 described from
Scandinavia. The larvae of this species are known to de-
velop on a non-native Spiraea species, indicating that the
species must have originated elsewhere (Lindqvist, 1974).
Revealing the origin of N. lipovskyi would involve inten-
VLYH¿HOG UHVHDUFKLQ DOO DUHDVZKHUH VRIWOHDYHGD]DOHDV
occur, as well as revising all the known species of Nematus
to eliminate possible synonymies.
The newly established population of N. lipovskyi in the
Botanical Garden in Prague consumed not only R. molle,
but also caused considerable damage to R. luteum and in-
ÀRUHVFHQFHVRIR. obtusum. Rhododendron luteum, there-
fore, is a new food plant for Nematus lipovskyi. R. luteum
is native to southeast Europe and southwest Asia. In Eu-
rope it occurs in neighbouring countries such as Poland
and Austria south through the Balkans and east to southern
Russia (Anisko & Czekalski, 1993; Resner, 2005; Ren-
cová, 2013). In Britain, as an invasive plant species, it has
colonised many wet peatlands and bogs (Pilkington, 2011),
whereas the Austrian and Polish populations are protected
(Rencová, 2013). Whether N. lipovskyi presents a poten-
tial risk to the native population of soft-leaved deciduous
rhododendrons, or whether it can be used to control this
species is unknown and needs to be tested. However, our
observations suggest that a mass occurrence of azalea saw-
ÀLHVFDQ OHDGWRFRPSOHWHGHIROLDWLRQZKLFKSUHYHQWVWKH
plant from reproducing. Moreover, after 3 successive years
of defoliation plants are visibly weaker and partial dieback
occurrs. In the USA, no large outbreaks followed by con-
tinuous defoliation of azalea plants are reported (D. Smith,
unpubl. data; Johnson & Lyon, 1991).
The present results based mostly on feeding tracks and
larval samples suggest Prague and its eastern outskirts to be
the very epicentre of this invasive species as the majority
of samples are recorded from this region. The most remote
UHFRUGVDUHIURP'ČþtQ1RUWK%RKHPLDDQG3O]HĖ:HVW
Bohemia). N. lipovskyiLVXQLYROWLQH ZLWK D OLPLWHGÀLJKW
period, therefore we consider the dispersal potential of
adults to be rather low or local. It is presumed that the pri-
mary agents of spread of this species might be young plants
carrying eggs and soil containing cocoons. On the other
hand a congeneric willow-feeding species N. oligospilus
(Förster, 1854) dispersed remarkably quickly when intro-
duced into the southern hemisphere (Urban & Eardley,
1995; Koch & Smith, 2000; Caron et al., 2013), therefore
the dispersal and distribution of this species across Europe
should be monitored.
ACKNOWLEDGEMENTS. We are grateful to D. Smith (USA)
for providing general information on the distribution and biology
RIWKHD]DOHDVDZÀ\ LQ WKH 86$DQGIRUYDOXDEOH FRPPHQWV RQ
the manuscript. C. Carrington (Prague, Czech Republic) kindly
proofread the English. We would also like to thank L. Pavlata
(Charles University Botanic Garden in Prague) for his help with
WKLVLQYHVWLJDWLRQ 75ĤåLþNDDQG3.DSLWRODERWK PHPEHUV RI
the State Phytosanitary Administration (which is currently a sec-
tion of the Central Institute for Supervision and Testing in Agri-
culture), kindly provided the data on the distribution of N. lipo-
vskyiFROOHFWHGE\WKH63$7KLVZRUNZDV¿QDQFLDOO\VXSSRUWHG
by Ministry of Culture of the Czech Republic (DKRVO 2014/12,
National Museum, 00023272).
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Received August 15, 2014; revised and accepted October 1, 2014
Prepublished online November 11, 2014
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