Ureche: Invasive in

INVASIVE LEAF MINER INSECTS IN ROMANIA

Camelia Ureche

University of Bacau, Faculty of Sciences, Marasesti Str. 157, Bacau 600115, Romania (e-mail: [email protected])

Abstract

Phyllonorycter robiniella Clemens was reared in leaves of pseudoacacia L. (Fabaceae). This species was found for the first time in Hemeius Park (Bacau district) in 2002. issikii (Kumata) was reared in leaves of Miller (Tiliaceae). This species was found for the first time in Podu Iloaiei (Iasi district) in 2002. These species have been recorded for the first time in the Romanian fauna.

Keywords: leaf miner, invasive species, Phyllonorycter robiniella, robiniella, Phyllonorycter issikii.

1. Introduction

The Romanian fauna of consists of 108 species belonging to 17 genera (Rákosy L. et al. 2003). These numbers include three invasive species: Clemens – which has been recorded in Romania for the first time in 1988, Phyllonorycter platani Stdgr., and Cameraria ohridella Deschka & Dimič which has been recorded in Romania for the first time in 1996 by Sandru. These three species and others are invasive species which have outspread in the European countries in the last 20 years. In most of cases invasive species have a substantial economic or/and ecological impact.

2. Material and method

The biological material consists of the mined leaves which were collected during the vegetation period. The first identification of the leaf mining species was made in the field by the characteristics of the mine. The mined leaves were kept in glass or plastic containers under laboratory conditions in order to obtain leaf miners adults and to know their bionomics. In some cases we tried to establish the attack parameters.

3. Results and discussion

3.1. Phyllonorycter robiniella Clemens and Parectopa robiniella Clemens

Phyllonorycter robiniella is one of the two pests of leaves, which mines on the lower surface, while Parectopa robiniella mines on the upper surface of the leaflets. These two species of leaf mining often cohabitate on the same leaflet. We found Phyllonorycter robiniella for the first time in Hemeius Park (Bacau district, East- Romania) in 2002. Scarcely in 2005 was this species observed by us in the Danube Delta

IUFRO Working Party 7.03.10 Proceedings of the Workshop 2006, Gmunden/ 259 Ureche: Invasive leaf miner insects in Romania

(Sulina, Letea Forest). Our observations were carried out mainly in Hemeius Park (Bacau district). The adult is a tiny . Its forewings are brownish with golden-beige pattern. Wingspan is about 5-6 mm (Fig. 1.a.). The larval development includes 5 instars, the last being white- greenish. The females lay eggs on the lower surface of the leaflets. The mine is initially a short gallery which later becomes a blotch mine. The larva of Parectopa robiniella develops solitary while the larvae of Phyllonorycter robiniella are gregarious.

a b c d

Figure 1. Phyllonorycter robiniella: a – adult; b – the upper surface of the leaflet; c – the lower surface of the leaflet; d – cocoons in mine.

The mature mine can occupy the whole lower surface of the leaflet and often contain more than one larva (Fig. 1.b., 1.c.). The pupation occurs within mine, in an elliptical silky cocoon (Fig. 1.d.). Phyllonorycter robiniella is a monophagous species and develops 2-3 generations per year in Central Europe. The complete development lasts 5-11 weeks, the last generation moths hibernate. Parectopa robiniella develops 2-3 generations per year, depending on the climatic conditions. Th es e two sp ecies cause i m portant damages to Robinia pseudoacacia (Table 1.).

Table 1. The infestation of the locust leaves by Phyllonorycter robiniella and Parectopa robiniella in the sampling sites in 1999-2002

Phyllonorycter Parectopa robiniella robiniella F total No. Sampling sites Data No. of leafletsF No. of leaflets F (%) total mined (%) total mined (%) 1 Cosmesti - GL 18.07.1999 332 58 17.47 2 Hemeius – BC 13.09.2000 709 190 26.79 3 Hemeius – BC 14.09.2001 561 160 28.52 4 Hemeius – BC 28.07.2002 79 27 34,17 5 Obirsia - BC 23.09.2002 137 2 0.73 179 44 24.58 25.41 6 Bacau 17.09.2002 221 20 9.05 7 Traian – BC 16.09.2002 172 23 13.37

This is the reason why scientists ha ve studied their parasitoid complex in many European countries. They found that the two complexes have common species because of the cohabitation of the two leaf miners moths. The parasitoid complex of Phyllonorycter

IUFRO Working Party 7.03.10 Proceedings of the Workshop 2006, Gmunden/Austria 260 Ureche: Invasive leaf miner insects in Romania robiniella in Serb ia for instance i ncludes 23 s pecies, most of them Eu lophidae (Stoia novič & Markovi 2005). In this complex includes 1 9 spec ies, most o f them Eulophidae (Melika et al. 2006). We have identified tw o parasi toid spe cies of Phyllonory cter rob iniell a: Mino tetrastichus frontalis Nees and C loster ocerus formosu s Westw. (Eulophidae), both of them identified also for Parectopa robiniella.

3.2. Phyllonorycter issikii Kumata

Phyll onorycter issikii is a leaf miner of different species of Tilia and it was introduced in Eastern Europe from eastern Asia probably during the seventies (the 20th century) (Šefrová 2002). It was found in (2000), Estonia, (2002), Hungary (2002), Lithuania, Russia, and . In Romania we found this species for the first time on the 21st of August 2002 in Podu Iloaiei (Iasi district), mining on Tilia cordata and then on 12th of October and 17th of October 2002, on 30th of August 2003 in Darmanesti (Bacau district), and on 2nd of October 2003 in Hemeius Park (Bacau district). The adult is a brownish moth with a wingspan of 6.5-7.5 mm and with two seasonal forms. Ground color of forewing is brownish, mixed with numerous blackish scales. The apex of the wings is edged by dark scales (Fig. 2.a.) (Noreika 1998). It develops two generations per year. The larvae makes large, elliptical blotch mines on the lower surface of the leaf (Fig. 2.b., 2.c.). The frass is within the mine, concentrated near its margin. Pupation occurs within mine, in a cocoon.

a b c

Figure 2. Phyllonorycter issikii: a – adult; b – the upper surface of the leaf; c – the lower surface of the leaf.

So far, Phyllonorycter issikii is not considered a pest in Romania, even if we found this species also on other forest species (unpublished data). It is possible that its density is controlled by the native polyphagous parasitoids as well as other natural factors. Being a recent invasive species its parasitoids complex was not yet studied.

4. Conclusions

Phyllonorycter robiniella is an important pest of Robinia pseudoacacia together with Parectopa robiniella. These two species develops 2-3 generations per year and the damage is how much more so the two leaf miner moths cohabitate on the same leaflet. The infestation

IUFRO Working Party 7.03.10 Proceedings of the Workshop 2006, Gmunden/Austria 261 Ureche: Invasive leaf miner insects in Romania rate of Phyllonorycter robiniella was 34.17% in 2002 in Hemeius Park, Bacau district (when it was observed for the first time). Phyllonorycter issikii is not yet considered a pest in Romania. Even this species is a leaf miner of different species of Tilia, we have found it also on other forest species (unpublished data).

5. References

MELIKA G., PÉNZES Z., MIKÓ I., CSÓKA G., HIRKA A., BECHTOLD M. 2006: Two invading black locust leaf miners, Parectopa robiniella and Phyllonorycter robiniella and their native parasitoid assemblages in Hungary. In CSÓKA G., HIRKA A., KOLTAY A. (eds.) 2006: Biotic damage in forests. Proceedings of the IUFRO (WP 7.03.10) Syposium held in Mátrafüred, Hungary, September 12-16, 2004, 144-156.

NOREIKA R.1998: Phyllonorycter issikii (Kumata) (, Gracillariidae) in Lithuania, Acta Zoologica Lituanica, Entomologia, 8 (3): 34-37.

RÁKOSY L., GOIA M., KOVÁCS Z. 2003: Catalogul lepidopterelor Romaniei [Verzeichnis der Schmetterlinge Rumäniens], Soc. Lepid. Rom. Cluj-Napoca, 446 pp (in Romanian, German).

ŠEFROVÁ H. 2002: Phyllonorycter issikii (Kumata, 1963) – bionomics, ecological impact and spread in Europe (Lepidoptera, Gracillariidae), Acta univ. agric. et silvic. Mendel. Brun., 2002, L, No. 3, pp. 99-104, Abstract.

STOIANOVIČ A., MARKOVI Č. 2005: Parasitoid complex of Phyllonorycter robiniella (Clemens, 1859) (Lepidoptera, Gracillariidae) in Serbia, Journal of Pest Science, 78 (2): 109- 114, Abstract.

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