Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 1
Express – PRA 1) for Aproceros leucopoda
Prepared by: Julius Kühn-Institut, Institute for Plant Health, 14 August, 2013
Dr. Gritta Schrader, Dr. Thomas Schröder; translated by Elke Vogt -Arndt
Initiation : Notification on occurrence in Germany, Bavaria on 2 8 November 2011 and in
Brandenburg on 7 August 2013 according to § 16.2 of Directive 2000/29/EC
Express - PRA Aproceros leucopoda
Phytosanitary Risk for
Germany
high medium low
Phytosanitary Risk for
EU-MS
high medium low
Certainty of Assessment High phytosanitary risk for the g enus Ulmus ; uncertainty
whether the complete g enus Ulmus is endangered. Rapid
natural spread is expected.
Taxonomy 1)
Hymenoptera, Argidae
Common name
Japanische Ulmenblattwespe, Zick -Zack -Ulmenblattwespe, zigzag
elm sawfly
Synonyms --
Biology
Parthenogenetic p ropagation, until now no males were found.
Very fast development (24-29 days from egg to i mago, Fig. 1);
several g eneration s per year (up to 4 in Hungary ). Imagines found
from mid April to the beginning of September in Hungary. Under
laboratory conditions up to 49 eggs per female are laid at leaf
edges (Fig . 2). 6 larval stages until the stage of the eunymph is
developed . Cocoons of the eunymphs, within which the pupation
takes p lace, are spun net -like, loosely, sometimes also sturdier.
Cocoons with sturdy walls were also found in leaf litter and
presumably serve for overwintering (Blank
et al. 2010; including
an identification key).
Is the pest a vector? 3)
No
Is a vector needed? 4)
No
Host plants In the literature U. glabra , U. japonica , U. laevis , U. minor , U.
minor x glabra, U. pumila and U. pumila var. arborea are cited
(Blank et al . 2010, Zandigiacomo et al. 2011, Kraus et al. 2011,
Crop Protection Compendium, 2012). It cannot be excluded that
the complete genus Ulmus is suitable as host plant s.
Symptoms 5)
Typical zigzag design in the leaf blade which reminds of a
meander (Fig. 3), bl urring with further voracity and growth of the
larvae (Fig . 4). Later only the mid leaf rib remains. Complete
defoliation of the infested trees is possible.
Presence of host plants in
Germany 6)
Wide spread (see distribution maps of different Ulmus speci es:
Ulmus minor , Fig. 5, U. glabra , Fig. 6, U. laevis, Fig. 7)
Presence of host plants in the
MS 7)
Wide spread (see f. e. EUFORGEN 2009)
Known infested areas 8) China, Japan, Russia ( Far East), Austria (Vienna, Lower Austria),
Germany (Bavaria), Hungary (Bàcs-Kiskun, Békés, Budapest,
Csongràd, Heves, Nògràd), Italy (Friuli -Venezia -Giulia, Veneto),
Poland (Sandomierz, Warschau), Ro ma nia (Banat ), Moldova ,
Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 2
Express - PRA Aproceros leucopoda
Slovenia, Slovakia , Serbia, Ukraine (Luhans’ka, Kharkiv oblast).
Pathways 9) Most likely : plants for planting, but also infested branches and
shootings. Growing season: larvae, eggs , cocoons . Out side of
growing season: overwintering cocoons in surface-near substrat e
(therefore spread also via soil) . In the literature the spread
alongside traffic lines was described, therefore possibly also
transport over lon g distances as „blind passenger“ is an important
factor.
Natural spread 10) From the end of April to the beginning of September when the
females are mature; deemed to be good flyers .
Expected establi shment and
spread in Germany 11)
Y es , since host plants are present a nd the pest already occurs in
areas with comparable climate. A first infestation outdoors with
propagation of A. leucopoda was already described in Germany
(Kraus et al. 2011).
Expected establishment and
spread in the MS 12)
Y es , see abo ve; moderate climate and Mediterranean region
Known damage in infested
areas 13)
Leaf feeding. Massive defoliation of infested trees was already
observed in the beginning of July in Hungary. Defoliation up to 98
%, in single cases 100%, after leaf r egeneration a new complete
defoliation was observed in the same year. Dieback of single
branches . Massive losses of the assimilation activity and
subsequently the production of res erve material. No age
prefer ence. No location preference. Esthetical problem (Blank et al.
2010).
Limitation of the endangered
area in Germany
Throughout Germany (see distribution maps of different Ulmus
species) .
Expected damage in the
endangered area in Germany 14)
Comparable with damage in infested areas. There is a risk that an
infestation with A. leucopoda could have a negative effect on
elms that are not infested by the Dutch Elm Disease (Brasier &
Gibbs, 1973) up to now. Depending on the host preference of A.
Leucopoda fu rther spread could have a considerable impact on
the breeding activities in the genus Ulmus aimed to control the
Dutch Elm Disease.
Expected damage in the
endangered area in MS 15)
Se e Germany. In all MS where Ulmus occurs. (f. e. distribution
Ulmus laevis : EUFORGEN, 2009).
Control feasibility and
measures 16) In Hungary
, insecticides ( deltamethrin e a nd t eflubenzuron ) were
used against larvae. These were effective against the larvae of
the first g eneration. In China pesticides were used which killed
more than 95% from the first and the second larval stage (Blank
et al . 2010). Despite this achievement it must be considered that
the zigzag elm sawfly is already widespread in Europe and that
a dult s are capable to re -colonize a treated area – therefore n o
sufficient result is expected from treatment with insecticides.
Furthermore the realization of use of insecticides in big trees is
difficult and would require the use of aircrafts. At the moment this
does not seem indicated . Insecticides would have to be used in
the frame of exemptions or „danger ahead“. Since no crop
endangering damage was described up to now this measure
seems not suitable.
Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 3
Express - PRA Aproceros leucopoda
Until now no effective parasitoids or other beneficial organisms
are known to be suitable for biological control ( Blank
et al. 2010).
Detection and diagnosis 17)
Body of the w asp app.6 mm, dark brown to black with pale legs.
Larvae (Fig. 8, adult app. 1 cm) green with 3 sternum pairs (with
T -like design ) and brown , striate colouring of the head-capsule .
Identificatio n key acc. to Blank
et al. 2010. Net-like or a lso
sturdier cocoons, eggs on the leaf edge of elms. Charac teristic
feeding design (zig zag design ).
Remarks
A further quick natural spread of the zigzag elm sawfly is
expected, mainly because of the parthenog enetic propagation a nd
the rapid development based on a short pupae rest, a fast and
light woven summer cocoon and the lack of natural enemies.
Spread mainly via transport routes and through river valleys is
expected.
Literature
Blank, S.M., Hara, H., Mikulás, J., Csóka, G., Ciornei, C.,
Constantineanu, R., Constantineau, C., Roller, L., Altenhofer, E.,
Huflejt, T., Vétek, G. 2010:
Aproceros leucopoda (Hymenoptera:
Argidae): An East Asian pest of elms (
Ulmus spp.) invading
Europe. Eur. J. Entomol. 107: 3 57-367.
Brasier, C.M.; Gibbs, J.N. 1973: Origin of the Dutch elm disease
epidemic in Britain. Nature 242: 607- 609.
Crop Protection Compendium, 2012
EPPO 2011:
Aproceros leucopoda : Addition to the Eppo Alert List.
EPPO Reporting Service 2011/198: 8- 9.
EPPO 2012: Aproceros leucopoda (Hymenoptera: Argidae), Alert
List;
http://www.eppo.org/QUARANTINE/Alert_List/insects/aproceros_le
ucopoda.htm
EUFORGEN 2009: Distribution map of European white elm
(Ulmus laevis ),
http://www.euforgen.org/fileadmin/www.euforgen.org/Documents
/Maps/PDF/Ulmus_laevis.pdf
Kraus,M., Liston, A.D., Taeger, A., 2011: Die invasive Zick -Zack -
Ulmenblattwespe Aproceros leucopoda Takeuchi, 19 39)
(Hymenoptera: Argidae) in Deutschland. Deutsche Gesellschaft für
allgemeine und angewandte Entomologie – Nachrichten 25 (3):
117- 119.
Zandigiacomo, P., Cargnus, E., Villana, A., 2011: First record of
the invasive sawfly Aproceros leucopoda infesting e lms in Italy.
Bulletin of Insectology 64 (1): 145- 149.
Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 4
Fig . 1:
Aproceros leucopoda , adult wasp (Ph oto: Csoka, Forestry Images)
Fig . 2:
Aproceros leucopoda , egg (Ph oto: Csoka, Forestry Images)
Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 5
Fig . 3:
Aproceros leucopoda , damage pattern of t he young larvae (Ph oto: Csoka, Forestry Images)
Fig . 4:
Aproceros leucopoda : damage pattern of older larval stage (Ph oto: Csoka, Forestry Images)
Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 6
Fig . 5: Distribution of
Ulmus minor in Germany (source: floraweb.de)
Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 7
Fig . 6: Distribution of
Ulmus glabra in Germany (source: floraweb.de)
Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Express-PRA for Aproceros leucopoda 14 August, 2013 page 8
Fig . 7: Distribution of
Ulmus laevis in Germany (source : floraweb.de)
Fig . 8:
Aproceros leucopoda , larva (Photo: Csoka, Forestry Images)
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Express-PRA for Aproceros leucopoda 14 August, 2013 page 9
Explanations
1) Compilation of the most important directly available informatio n allowing a first preliminary
estim ation of the phytosanitary risk. This short assessment is necessary for the decision on a
notification to EU and EPPO as well as the preparation of a complete risk analysis, for the
information of the countries and as a basis for the possible initiation of eradication measures.
Regarding the phytosanitary risk especially the possibility of the introduction into and spread in
Germany and the Member States as well as possible damage are taken into account.
2 ) Taxonomic cla ssification – also subspecies; in case that the taxonomical classification is uncertain the
JKI -scie ntist in itiates the taxonomic classification, as far as possible.
3) If so, which organism (which organisms) is (are) transmitted and does it (do they) occ ur in Germany
/ the MS?
4) If so, which organism serves as a vector and does it occur in Germany / the MS?
5) Description of the pattern of damage and the severity of the symptoms/damage on the different host
plants
6) Presence of the host plants in pro tected cultivation, open field, amenity plantings, forest.
Where, in which regions are the host plants present and to which extent?
How important are the host plants (economical, ecological,..)? Possible origin
7) Presence of the host plants in protecte d cultivation, open field, amenity plantings, forest, ....;
Where, in which regions are the host plants present and to which extent?
How important are the host plants (economical, ecological,..)? Possible origin
8) f. e. acc. to CABI, EPPO, PQR, EPPO Datasheets
9) Which pathways are known for the pest and how important are they for the possibility of
introduction? Primarily the transport of the pest over long distances is meant, normally with infested
traded plants, plant products or other contaminated a rticles. This does not comprise the natural
spread resulting from introduction.
10) Which pathways are known for the pest and of which relevance are they in respect of the possibility
of spread? In this case the natural spread resulting from introduction is meant.
11) under the given prevalent environmental conditions
12) under the given prevalent environmental conditions (native areas and areas of introduction)
13) Description of the economic, ecological/environmental relevant and social damage in the area of
origin resp. areas of occurrence up to now
14) Description of the economic, ecological/environmental relevant and social damage to be expected in
Germany, as far as possible and required, differentiated between regions
15) Description of the economic, ecological/environmental relevant and social damage to be expected in
the EU/other Member States, as far as possible and required, differentiated between regions
16) Can the pest be controlled? Which possibilities of control are given? Are plant h ealth measures
conducted in respect to this pest (in the areas of current distribution resp. by third countries)?
17) Description of possibilities and methods for detection. Detection by visual inspections? Latency?
Uneven distribution in the plant (sampl ing)?
