original scientific paper UD C 595.78(497.4) 
HORSE-CHESTNUT LEAFMINER (CAMERARIA OHRiDELLA DESCHKA ET 
DIMIČ, 1986) IN SLOVENiA (INSECTA, L.EPIDOPTERA, LITHOCOLLETIDAE) 

Katja ZELBNKO 
Department of Biology, University of Maribor, Si-2000 Maribor, Koroška 160 
Dušan DEVETAK 
Department of Biology, University of Maribor, S!-2000 Maribor, KoroSka 160 
Michael STELZL 
Mygienicuro, A-8045 G ras, Andritzer Reichsstrasse 44 
ABSTRACT 
Horse-chestnut !eafminer (Cameraria ohridella) is a serious pest of horse-chestnut, which has in the last decade been introduced from the south of the Balkan Peninsula to Central Europe. Distribution and life history of the moth in Slovenia is presented in the paper. In the period between 1996 and 1998 we studied the life cycle of the pest. Mechanical traps have been used to determine the number of generations. In Slovenia, the occurrence of three gen­erations per year has been confirmed. Some information on density and mortality of the pest has been obtained. 
Key words: Cameraria ohridella, Lepidoptera, Aesculus hippocastanum, life history, Slovenia 
INTRODUCTION 

The Lithocolletid genus Cameraria is distributed in Europe, Middle and Far Easts and America. The only European species, Cameraria ohridella, was for the first time detected in 1984 in Ohrid, Macedonia (Sirnova-Toiic & Filev, 1985). Two years later, the moth was recognized and described as a new species by Deschka & Dimid (1986). A few years later, C. ohridella was detected in Upper Austria (1989); it had been brought there from the south of the Balkans and started to spread very rapidly over Austria and the neighbouring coun­tries. 
C. ohridella, a horse-chestnut leafminer, is a mono­phagous species attacking horse-chestnut (Aesculus hip­pocastanum L.) and is a serious pest in Europe. Adults and pre-imaginal stages have been studied by Deschka & Dimie 0986) and Pschorn-Walcher (1994). 
Damage in horse-chestnut is caused by the larval stages of the moth (Figs. 3, 4, 5). The mines are on the upper surface of the leaves, and each mine usually contains a single larva (Fig. 2). Many mines occur on a single leaf (Figs. 3, 4). The larvae feed on mesophyll between larger veins of the leaf. The larva pupates in a cocoon inside the mine. C. ohridella overwinters as a pupa in dry leaves. 
Adults occur from April to September. Females lay eggs on the upper side of the leaves. The larvae (Figs. 2, 6, 7) hatch in 2-3 weeks, entering the leaf directly from the egg. The first three instars live as sap feeders mining the leaf in a circle (Pschorn-Walcher, 1994). Instars 4 and 5 are the so-called tissue feeders enlarging the mine in asymmetric areas. Instar 6 starts the pupation by de­positing the feces from the digestive system (Pschorn-Walcher, 1994). 
The larvae grow more than three weeks. After that period pupation begins. Pupal stage (Fig. 8) lasts for about two weeks (in summer) or six months (in the overwintering generation), until new adults emerge from the silken cocoon (Deschka & Dimici, 1986; Pschorn-Walcher, 1994). Some authors (Deschka & DimiC 1986; Pschorn-Walcher, 1994) presume that C. ohridella develops three overlapping generations per year. The possibility of four or even more generations has also been mentioned (Maceljski & Bertie, 1995). 
Katja ZELENK O el a I. : HORSE-CHESTNUT LEAFMINER (CAMERARIA OHRIDELLA DESCHK A ET DIMIČ, 1986) IN SLOVENIA ..., 8! -88 
Fig. 1: First occurrence of the pest in the European countries. 
SI. 1: Prvo pojavljanje škodljivca v evropskih državah. 

Since 1989, the species has expanded in the follow­ing European countries (Fig. 1): Austria, Croatia, Czech Republic, Germany, Hungary, Italy, Slovakia and Slo­venia (Puchberger, 1990; Butin & Führer, 1994; Las­tuvka, 1994; Pschorn-Walcher, 1994; Maceljski & Ber­tič, 1995; Liska, 1997; Milevoj & Maček, 1997; Sivicek et al., 1997; Szaboky, 1997). Additional information on distribution and biology of the pest has been published by ßlümel & Hausdorf (1997), Holzschuh (1997), Jure (1997), Kenis (1997), Lethmayer & Grabeneger (1997), Perny (1997), Pschorn-Walcher (1997), Schmidt (1997), Stolz (1997), Tomiczek (1997) & Wieser (1997). 
The first occurrence of C. ohridella in Slovenia was recorded in 1995 (Maceljski & Bertič, 1995; Milevoj & Maček, 1997). In this paper distribution of the species in Slovenia and its life history are presented. 
Fig. 2: The larva of C. ohridella inside its leafmine 
SI. 2: Larva vrste C. ohridella v rovu. 

Figs. 3, 4: Leaf mines on the leaf of horse-chestnut. 
SI. 3, 4: Rovi v listu divjega kostanja. 

Fig. 5: A strongly damaged leaf. 
SI. 5: Močno poškodovan list. 

Fig. 6: Second instar larva. Bar 100 pm. 
SI. 6: Larva druge stopnje. Merilo 100 pm. 

Fig. 7: Fourth instar larva. Bar 100 pm. 
SI. 7: Larva četrte stopnje. Merilo 100 pm. 

Fig. 8: Pupal exuviae. Bar 1 mm. 
SI. 8: Exuviae bub. Merilo 1 mm. 


AN N ALES • Ser. hist, nat. • 9 • 1999 • 1 (15) 
83 


Kaija ZELENK O ef ,7!.: HORSE-CHESTNUT I.EAFMINER (CAMBRARIA OHRIDEUA DESCHK A ET DIMtČ, 1986} IN SLOVENIA 81-83 
Fig. 9: Distribution of C. ohridella in Slovenia. SI. 9: Razširjenost vrste C. ohridella v Sloveniji. 
MATERIAL AND METHODS 
Distribution in Slovenia 
In the period from 1996 to 1998 many horse-chest­nut locations in Slovenia were investigated. The loca­tions are listed with the UTM coordinates. 

Observation of life cycle 
To define the number of generations, we observed development of C. ohridella in leaves inside mechanical traps and in intact leaves. As mechanical traps, 120 x 60 cm large textile bags (Vrteks, Tosama) were used. They were placed on horse-chestnut branches in the area of Magdalenski park in Maribor. Observation of the larvae in intact, leaves was carried out at three different locali­ties in Maribor (Magdalenski park, Tomšičeva ulica and Strossmayerjeva ulica). 
Individuals inside the traps were marked with differ­ent paints (Edigs, Pelikan). We marked the leaf mines caused by the larvae of the first generation with white paint. Thereafter we observed their development inside the mechanical traps as well as in free land. When the larvae of the second generation occurred, we marked their mines with pink paint. Beside six old mechanical traps we mounted four new ones, on four branches closer to the centre of the tree canopy. In first six traps the leaves were damaged to such an extent that the de­velopment of the larvae of the third generation could not be completed. When the larvae of the third generation occurred, we marked their mines with blue paint. The observation has been carried out until the middle of No­vember 1997. 
Density of the larvae was expressed as the number of the larvae per leaf area. Leaves were collected in Mari­bor at the following localities: Popovičeva ulica, Mag-
L 
3. generation OOWJOOl) 0 0 0 0 
2, generation 00000» 0 0 0 0 0 0 0 0 0 0 0 0 
1. generation OOOOODOOOM 
overwintering generation 
' |
' i ' i ' I ' 1 ' 1 ' ! 
April Maj June July August September October November 
Legend; * - adult 
- iarvae 
0 - pupa 

Fig. 10: The life cycle of C. ohridella in Maribor in the year 1997 SI. 10: Razvojni cikel vrste C. ohridella v Mariboru v letu 1997. 
daienski park, Tomšičeva ulica and Strossmayerjeva ulica. We collected 20 leaves at each locality (4 trees; from each 5 leaves). 
RESULTS 



Distribution in Slovenia 
C. ohridella has been recorded in the following places (Fig. 9): 
Ajdovščina (VL 18) 22.V. 1998, Bakovcl (WM 86) 30.VI.1997, Begunje (Cerknica) (VL 57) 24.V.1997, Bis­trica ob Sotii (WM 50) 3.IX. 1997, Brezovica (Poljanska gora) (WL 59) 3.IX.1997, Brežice (WL 48) 3.IX.1997, Buče (Kozje) (WM 40) 3.IX. 1997, Cajnarje (Velike Bloke) [VL 57) 3.IX. 1998, Celje (WM 22) 24.V.1997, Cerknica (Rakek) (VL 57) 3.IX.1997, Čepinci (WM 99) 30.VI.1997, Črnomelj (WL 14) 3.IX.1997; Dolenja vas (Ribnica) (VL 86) 3.1X.1997, Dolga vas (Kočevje) (VL 95) 

3.!X.1997, DragatuŠ (WL 14) 3.IX.1997, Dvor (Žu­žemberk) (VL 97) 3.IX.1997, Fram (WM 54) 10.VN.1997, Grahovo (Cerknica) (VL 56) 3.IX.1997, Imeno (WM 41) 3.IX.1997, Ivančna Gorica (VL 88) 3.IX.1997, Jugorje (Metlika) (WL 16) 3.IX. 1997, Kobarid (UM 82) 21 .Vili.1997, Kočevska Reka (VL 84) 3.IX.1997, Krmelj (Mokronog) (WL 19) 3.IX. 1997, Krško . (WL 39) 3JX.1997, Kvasica (Črnomelj) (WL 14) 3.IX.1997, Livold (VL 95) 3.IX.1997, Ljubljana (VM 50-VM 60) 24.V.1997, 
20. X.1998, Mačkovci (WM 98 ) 19.VI.1997, Maribor (WM 55) 20.VII.1996, 20.X.1998, Metlika (WL 25) 3.IX.1997, Mirna (WL 08) 3.IX.1997, Mokronog (WL 18) 24.V.1997, Mozirje (VM 93) 7.VIII.1997, Nazarje (VM 93) IX.1997, 7.VIII.1998, Novi Lazi (Kočevska Reka) (VL 84) 3.IX.1997, Novo mesto (WL 17) 24.V.1997, Ortnek (VL 77) 3.9.1997, Podčetrtek (WM 41) 3.IX.1997, 

Katja ZEtENK O el at.: HORSE-CHESTNUT LEAFMINFR (CAMBRARIA OHRIDELLA DESCHK A ET DIMIČ, 1986) tN SLOVENIA ..., 81-88 
Poljčane (WM 43) 20.V.1997, Rakek (VL 47) 3.IX.1997, Ribnica (VL 76) 3.1X.1997, Rimske Toplice (WM 10) 24.V.1997, Rogaška Slatina (WM 52) 20.V.1997, Sežana (VL 16) Vili.1997, Slovenska Bistrica (WM 43) 21.V1I.1996, 20. X. 1999, Sodražica (VL 76) 3.1X.1997, Stari Log (VL 96) 3.IX.1997, Stari trg (WL 03) 3.IX.1997, Strunjan (UL 94) 8.V1.1997, IX.1997, Škofljica (VL 69) 24.V.1997, Štalcerji (VL 94) 3.IX.1997, Tolmin (VM 01) 21 .Vili.1997, Trebnje (WL 08) 3.IX. 1997, Tržišče (WL 19) 3.IX.1997, Turjak (VL 68) 24.V.1997, Velike Lašče (V I 77) 3.IX.1997, Vrhovo (VL 19) 3.IX.1997, Zagradec (Žužemberk) (VL 87) 3.IX.1997, Zamostec (VL 76) 3.IX.1997, Zidani Most (WM 10) 24.V.1997, Žužemberk (VL 97) 3.IX.1997. 

Life cycle of C. ohridella in Slovenia 

in Slovenia, C. ohridella develops three overlapping generations. A certain number of the pupae of the sec­ond generation and ail the pupae of the third generation overwinter (Fig. 10). 
Studying the insects inside the traps it was concluded that the larval stage lasts longer in every successive gen­eration. The result was confirmed also in free-land in­vestigation. Duration of the instars of different genera­tions in the mechanical traps and in free-land is shown in Fig. 11. Larval stages were shorter in Tomšičeva ulica and Strossmayerjeva ulica than in Magdalenski park. Each successive larval stage is prolonged. Pupal stage in the second and the third generations lasts longer than in the first one. Duration of all pupae of the first and of some pupae of the second generation lasts approxi­mately 14-16 days (Fig. 11). 
In the year 1997 adults of the overwintering genera­tion occurred from the end of April to the end of May. In the traps adults of the first generation were detected from mid June to the beginning of August, and adults of the second generation from the beginning of August to the end of September (Fig. 10). In free-land, adults were sporadically detected even on 10th October 1997. Im­portant information regarding the number of generations is the period at the end of the season when young larvae still occur. First and second instar larvae were still de­tected at the end of September. 
The larval density of each generation was the highest in the area of Magdalenski park (Fig. 12). At this locality, the densities of the third generation was lower in com­parison to the first and second ones (Fig. 12). At the other three localities, the density increased with the generations number. 
Strong relationship between percentage of the pupae of the second generation that overwinter and the num­ber of the larvae of the same generation in the traps was established (Fig. 14); the correlation was high (r = + 0.94). 
The defoliation of horse-chestnut trees, caused by C. ohridella, was completed in Magdalenski park at the beginning of September, at the other localities with a lower pest density even in mid November. 
• i 
r 
I 
tfi L 
in t-. 
111 
1. generation ! 2. generation I 3. generation 

Legend: IN TRAPS; g - larva 
111!! -P"Pa 
p*] - larva 
- papa 

Fig. 11: Duration of the pre-imaginal stages of different 
generations in traps and in free-land. 
Sf. 11: Trajanje preimaginalnih stadijev različnih gene­racij v pasteh in na prostem. 

Katja ZÉLÉNKO el si/. HORSE-CHESTNUT LEAFMINER (CAMERARIA OHRIOELLA DESCI tKA ET DIMIČ, 198 « IN SLOVENIA .... [11-08 
gsrcoraílon T 
M 	gensr!}*k>n 2 
M
yenetrthfi 3 
r-WI . JEHCL 
Fig. 12; Density of each generation at different lo­catiiities. SI. 12; Gostota generacij na različnih lokalitetah. 


Potential parasites 
Irt the traps three pupae of an unidentified hymenop­teran parasite were found. 

DISCUSSION 
C. ohridella is a serious pest of horse-chestnut in many European countries. 
The occurrence of the insect in Slovenia was re­ported for the first time by Maceljski & Bertič (1995). As Tomiczek (1997) and Sivicek ef a/. (1997) reported, the species expands rapidly. 
To determine the number of generations, the method with mechanical traps has been used in C. ohridella for the first time. Investigations of the development in the traps and in free-land in Maribor confirmed that three overlapping generations occurred in the period from April to November 1997. The life cycle of the moth in Slovenia is comparable with the cycle in Austria (Pschorn-Walcher, 1994). 
At one locality, the density of the third generation was lower in comparison to the first and second ones (Fig. 12). Here, the high density of the second genera­tion influenced high mortality (Fig. 13), resulting in lower density of the third generation. At low density lo­calities the duration of the larval stages is shorter than at high density places. 
The pest overwinters as pupa of the second or third generation. The larval density of the second generation is positively correlated with the percentage of the pupae of the same overwintering generation; the relationship is high (r = + 0.94). 
At three localities in Maribor, the larval densities were different. The highest density in Magdalenski park could be explained as a result of a less intensive re­moving of the leaves during the last autumn, so the higher number of the pupae has survived the winter. 


ACKNOWLEDGEMENTS 
We thank Mr. F. Kuhar (Fiorina - parki, Maribor) for his permission to carry out investigations in Magdalenski park, Dr. I. Hrasovec (Zagreb) and S. Gomboc (Ljub­ljana) for providing some teíevant references, and Dr. T. Novak (Maribor) for his critical reading of the manu­script. 
10 0 
90 80 
7 0 
60 
e 
50 
o 
L 
40 30 
20 
10 
0 generation 
•	 2. generation generation 

IS 30 45 60 75 90 105 120 
Number of the larvae in the trap 
Fig. 13: Relationship between mortality and density of the larvae within the same generation. SI. 13: Povezava med mortaliteto in gostoto larv iste generacije. 
ANNALES • Ser. hist. nat. - 9 • 1999 • 1 {15) 
Katja z a EN K O ef a/.: HORSE-CHESTNUT IEAFMINER (CAMERARIA OliRIOEUA DESCHKA ET DIMiC, 1986) IN SlOVENtA ..-, 81-88 

34  
32 ­ 
30 ­ 
28  
26  
24  
22 20  • trap 1  
18  • trap 2  
16 14 12  A t rap 3 Xtrap 4  
10  
8  
6  -j  
4  X  
2  
0  
10  15  20  
Number of the larvae/loaf  

Fig. 14: Relationship between the percentage of the pupae of the second generation which overwinter and the 
number of the larvae of the same generation in the trap. 
Si. 14: Povezava med odstotkom prezimujočih bub druge generacije in številom larv iste generacije v pasteh. 

LISTNI ZAVRTA Č DiVJEGA KOSTANJ A { CAMERARI A OHR1DELLA DESCHK A ET DIMIČ, 1986) V SLOVENij i (iNSECTA, LEPIDOPTERA, LITHOCOLLETiDAE ) 
Katja ZELENKO 
Oddelek za biologijo, Univerza v Mariboru, SI-2000 Maribor, KoroSka 160 
Dušan DEVETAK 
Oddelek za biologijo, Univerza v Mariboru, SI-2000 Maribor, Koroška 160 
Michael STELZL 
Mygienicum, A-8045 Graz, Andritzer Reichsstrasse 44 
POVZETEK 
Cameraria ohridella Descbka et Dimič je nevaren škodljivec divjega kostanja. Škodljivca so odkrili v Makedoniji teta 1984. Od leta 1989 se je vrsta razširila po deželah srednje in vzhodne Evrope (zanesena v Avstrijo se je nato razširila na Češko in Hrvaško, v Italijo, na Madžarsko, v Nemčijo, Slovaško in Slovenijo). 
Zavrtača divjega kostanja so v Sloveniji prvič ugotovili leta 1995. V pričujočem prispevku navajamo podatke o razširjenosti škodljivca v Sloveniji. Z mehanskimi pastmi vrečaste oblike smo onemogočili migracije osebkov. Ugo­tovili smo, da se pri nas razvijejo tri generacije Škodljivca in da prezimujejo bube tretje in nekaj bub druge gene­racije. 
Ključne besede: Cameraria ohridella, Lepidoptera, Aesculus hippocastanum, življenjski ciklus, Slovenija 
Katja ZELEN K Ö et ah BOKSE-CHESTNUTIEAFMINE K (CAMERARIA OHKIOBLIA DESCHK A ET DIMIČ, 1986) i N SLOVEN1A ..., 8 t-S B 
REFERENCES 

Blümel, S., & Hausdorf, H. 1997. Versuche zur Kon­trolle von Cameraria ohridella Deschka & Dimic mit Insektiziden Wachstumsregulatoren. - Forstschutz Aktu­ell, 21, 16-18. Bulin, H. & Führer, L, 1994. Die Kastanien-Miniermotte (Cameraria ohridella Deschka & Dimic) einere neuer Schäding an Aesculus hippocastanum. - Nachrichtenbl. Dtsch. Pflanzenschutzd., 46 (5), 89-91. Deschka, G. & Dimič, N. 1986. Cameraria ohridella sp. 
n. (Lep., Lithocolletidae) aus Mazedonien, jug. - Acta entomoi. jug., 22, 11-23. Hoizschuh, C. 1997. Woher kommt die Rosskastanien­miniermotte wirklich? - Forstschutz Aktuell, 21, 11 -12. Jure, M. 1997. Listna suSica (Guignardia aesculi /Peck./ Stev.) in listni zavrtač divjega kostanja (Cameraria ohri­della Deschka et Dimič) ogrožata navadni divji kostanj v Sloveniji. - Gozdar, vestn., 55, 428-434. Kenis, M. 1997. Möglichkeiten einer biologischen Kon­trolle von Cameraria ohridella mit eingeführten natür­lichen Feinden. - Forstschutz Aktuell, 21, 27-29. Lastuvka, Z. 1994. Faunistic records from the Czech Re­public. 18. - Klapaiekiana, 30, 197-206. Lethmayer, C. & Grabenweger, G. 1997. Natürliche Parasitoide der Kastanienminiermotte (Cameraria ohri­della). - Forstschutz Aktuell, 21, 30. Liska, }. 1997. Verbreitung der Rosskastanienminier­motte in der Tschechischen Republik. - Forstschutz Aktuell, 21, 5. 
MaceJjski, M. & Bertič, D. 1995. Kestenov moijac miner - C. ohridella Deschka & Dimič (Lep.: Lithocolletidae) ­novi opasni štetnik u Hrvatskoj. - Fragm. phytomed. herbolog., 2, 9-18. 
Milevoj, L. & Macek, j. 1997. Rosskastanien-Mini­ermotte (Cameraria ohridella) in Slowenien. - Nachrbl. Dtsch. Pflanzenschutzd., 49, 14-15. 
Perny, B. 1997. Erste Ergebnisse populationsgenetischer Untersuchungen von Cameraria ohridella. - Forstschutz Aktuell, 21, 13-15. Pschorn-Walcher, H. 1994. Freiland-Biologie der ein­geschleppten Rosskastanien-Miniermotte Cameraria ohridella Deschka et Dimic (Lep., Gracillariidae) im Wienerwaid. - Linzer biol. Beitr., 26 (2), 633-642. Pschorn-Walcher, H. 1997. Zur Biologie und Popu­lationsentwicklung der eingeschleppten Rosskastanien-Miniermotte, Cameraria ohridella. - Forstschutz Aktuell, 21, 7-10. Puch berger, K. 1990. Cameraria ohridella Deschka & Dimic: (Lep. - Lithocolletidae) in Oberösterreich. - Steyer Entomologenrunde 24, 79-81. Schmidt, H. 1997. Verbreitug der Rosskastanienmini­ermotte in Deutschland. - Forstschutz Aktuell, 21,3. Simova-ToSic, D. & filev, S. 1985. Prilog poznavanju minera divljeg kestena. - Zastita bilja, 36 (3), 235-239. Sivicek, P., Hrubik, P. & juhasova, 8.1997. Verbreitung der Rosskastanienminiermotte in der Slowakei. - Forst­schutz Aktuell. 21,6. Stolz, M. 1997. Untersuchungen über Larval- und Puppenparasitoiden von C. ohridella in Hinblick auf ihre Eignung zur Laborzucht, - Forstschutz Aktuell, 21, 
31. 
Szabóky, C. 1997. Verbreitung der Rosskastanienminier­motte in Ungarn. - Forstschutz Aktuell, 21, 4. 
Tomiczek, C. 1997, Verbreitung der Rosskastanien­miniermotte in Österreich. - Forstschutz Aktuell, 21, 2. 
Wieser, C. 1997. Die Rosskastanienminiermotte (Came­raria ohridella Deschka & Dimic, 1986), auch in Kärn­ten in rasanter Ausbreitung begriffen (Lepidoptera, 
Gracillariidae). - Carinthia N, 187/107, 133-138.