DISTRIBUTION OF THAUMETOPOEA PROCESSIONEA (L.) IN BULGARIA

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1 Silva Balcanica, 12(1)/2011 DISTRIBUTION OF THAUMETOPOEA PROCESSIONEA (L.) IN BULGARIA Plamen Mirchev, Georgi Georgiev Forest Research Institute Sofia Bulgarian Academy of Sciences Stefan Balov Executive Agency of Forestry- Sofia Maria Kirilova Forest Protection Station Varna Antonina Georgieva Forest Protection Station Sofia Abstract In Bulgarian entomological literature, data on the oak processionary moth appear at the end of the ІХ century. The first registered habitat is Belogradchik. Data on the volume of attacks by oak processionary moth have existed since Out of 18 forestry enterprises, where the oak processionary moth is registered as a pest, 11 are in Eastern Bulgaria. The sizes of the areas attacked delineate three peaks in the dynamics of its numbers for the 58-year period since 1953: first 1960, second 1970 and third In case of high numbers of the pest on large areas, treatments were done by airplanes or helicopters. In Bulgaria out of the biological factors suppressing the numbers of the oak processionary moth, on eggs, caterpillars and pupae have been established 11 parasitoids. Key words: Thaumetopoea processionea, Bulgaria, distribution INTRODUCTION The oak processionary moth, Thaumetopoea processionea (Linnaeus, 1758) (Lepidoptera: Notodontidae) is spread almost throughout Europe (Maksymov, 1978). The species is absent in only some of the northern and southern parts of the continent. It is not found in Scandinavian Peninsula, Baltic republics, eastern part of European Russia, Belarus, European part of Turkey, Malta, the Azores islands, etc. (Fauna europea, 2007). T. processionea is a homophag, feeding on the leaves of the genus Quercus (Dissescu, Ceianu 1968; Maksymov, 1978). Baker et al. (2009) emphasize that the mention in some publications of trees of the genera Betula, Carpinus, Castanea, Corylus and Fagus as feeder plants are not supported by data. 71

2 Mass attacks by this pest have been registered in a number of European countries Austria, Italy, Germany, Poland, France, Romania, Moldova, former Yugoslavia republics (Maksymov, 1978). There are at least two grounds for treating the oak processionary moth as a pest: the economic losses caused, manifested in reduced growth and even drying of part of the oak forests attacked, and second the direct negative impact on the health of people and animals, manifested as allergic reactions, caused by the hairs of the caterpillars (Lamy, 1990). The aim of this paper is to specify the significance of this pest for Bulgaria and, on the base of data from the literature, to determine the species area and the natural factors regulating its number. After the Second World War, the forestry authority started systematic examination of forests for insect pests and diseases. On the base of these archival data, we aim to determine: through quantitative data of the surfaces attacked, the regions of incidence of the species; the dynamics of its population numbers for a 58-year period ( ); and the zones of extreme proliferation in the country, determined by the objective indicator of the control measures taken. The data on the amount and distribution of the species feeder plant oak forests are to define the potential for the spread of the oak processionary moth. The administrative management of forests in Bulgaria is exercised by a Central Authority (Executive Forest Agency) with 15 regional departments Regional Offices in Forests (ROF), each of them composed of State Forestry Enterprises (SFE) or Game Breeding Stations (GBS). The data on the oak processionary moth for the period after 1953 have been collected by administrative units forestry enterprises or game breeding stations. FOOD BASE OF THE OAK PROCESSIONARY MONTH IN BULGARIA Forests in Bulgaria account 34.9 % of its territory. In 1990 they were ha, out of which ha coniferous, and ha deciduous. The surface area of the pure oak forests is ha or 26.9% of the forest stands, and 41.0 % of deciduous plantations of the country (Forestry, 1992). Oaks also participate in mixed plantations with other tree species, and thus their surface area grows to ha (Marinov et al., 1995). Forestry literature in Bulgaria uses a division between oak, and Turkey oak forests. The figures cited above refer to summarized data for those two categories, named generally oak forests. Oak forests are found throughout the country (Table 1), primarily in the lower forest-growth belt at altitude of up to 1000 m (Marinov et al., 1995). Their sparsest participation is in Central North Bulgaria, this is also the region with the lowest forestation, and their highest relative share is in South-Western Bulgaria 15.5 ha per 1 km 2 of surface area. The data show the presence of a food base for the successful development of the oak processionary moth in all parts of Bulgaria. 72

3 Name Regions of Bulgaria Table 1 Distribution of oak forests in Bulgaria Including districts with centres Area, km 2 (1) Distribution of oak forests Area, ha (2) % ha/1 km 2 North-Western Vidin, Montana, Vratsa North Central North-Eastern South-West South Central Lovech, Pleven, Gabrovo, Veliko Tarnovo Ruse, Razgrad, Targovishte, Shumen, Silistra, Dobrich, Varna Sofia, Pernik, Kyustendil, Blagoevgrad Plovdiv, Pazardzhik, Smolyan, Haskovo, Kardzhali, Stara Zagora South-East Burgas, Sliven, Yambol Total for Bulgaria According to data: According to data: (Forestry ). INCIDENCE OF THE OAK PROCESSIONARY MOTH IN BULGARIA Information on the species up to 1945 In Bulgarian entomological literature, data on oak processionary moth appear at the end of the IX century. Mitrev (1894), an anonymous article (B.1899) in Oralo newspaper provide data on the morphology and biology, and recommend some measures to restrict the damages caused by the species. The first registered habitat is Belogradchik (Fig. 1), from where the regional inspector of the State Agricultural Experimental Station in Obraztsov Chiflik reports that in May 1908 this species, named in Bulgarian processionary butterfly is quite widespread in the oak forests in the region (Kosaroff, 1909). In the same 1908, an editor s note in Lesovadska Sbirka magazine records that data have been obtained from many forestry regions of attacks by oak processionary moths,... and in such measure at that, that trees in large forest areas are... defoliated (Anonym, 1908). Tchorbadjiev (1915) finds caterpillars of oak processionary moth on Quercus pedunculata in Kara Bair and Ala-tepe, which he cultivated to imago. On 7 August 1911, with a light lamp he catches one female individual in Chengene Skele. The three habitats are in the region of Burgas. Kara Bair is a hill to the west of the present-day town of Bulgarovo. Ala-tepe is a site 16 km south of Burgas, on the land belonging to the village of Rosen, the municipality of Sozopol. Chengene Skele is in the proximity of the village of Marinka, which, since 1995, has had the status of protected area measuring 160 ha. 73

4 M A C E D O N I A E of Greenwich S E R B I A Vidin R O M A N I A D a n u b e R i v e r Belogradchik Godech Sofia Aramliets Samokov Pirdop Plovdiv Shumen Varna Tsonevo Provadia Staro Smiadovo Oriahovo Kotel Sliven Karnobat Burgas Novo Panicharevo T U R K E Y Balchik 50 km Kosti Black Sea G R E E C E Fig. 1. Distribution of T. processionea in Bulgaria Data on new habitats of the species are provided by Buresch (1930), who indicated the oak forests at the mouth of Kamchia River, around St. Konstantin Monastery; at Vurgary (the present-day village of Bulgary) and Vasiliko (the present-day town of Tsarevo) in Strandzha mountain. St. Konstantin Monastery is located 8 km to the north of Varna, in the centre of the present-day resort St. St. Konstantin and Elena. Buresch, Tuleschkow (1930) summarized the known data on the incidence of the species, coming to the conclusion that it is found only in Eastern part of the country, ignoring, for some reason, the publication of Kosaroff (1909). They add a new habitat in the region of Sliven. The report by Bozhkov (1931) of finding the species in the Plovdiv region expands the established area of the oak processionary moth in Bulgaria. For the region of Varna, Buresch, Karnojitski (1942) added a new habitat... in the outskirts of Gyundyuz forest above Ses-Sevmez (Ses-Sevmez is the present-day Asparuhovo residential district of Varna). Data on the species after the Second World War The data in Tables 2, 3 and 4 were obtained from the archives of the Executive Forest Agency and its three divisions Forest Protection Stations in Sofia, Varna, and Plovdiv. As it has been pointed above, data from studies of the forest plantations on the volume of attacks by oak processionary moth have existed since 1953, but no information on the location of such attacks has been found in the archives for the period 74

5 Table 2 Information on regions infested by oak processionary moth in Bulgaria after 1968 Region Year Area, ha Region Year Area, ha ROF Varna SFE Staro Oriahovo ROF Varna SFE Staro Oriahovo ROF Shumen SFE Staro Oriahovo ROF Burgas SFE Staro Oriahovo ROF Sofia SFE Staro Oriahovo SFE Varna SFE Kosti SFE Varna SFE Tsarevo SFE Varna SFE Tsarevo GBS Balchik SFE Tsarevo GBS Balchik SFE Tsarevo GBS Balchik SFE Novo Panicharevo GBS Balchik SFE Novo Panicharevo GBS Balchik SFE Novo Panicharevo GBS Balchik SFE Novo Panicharevo GBS Balchik SFE Karnobat GBS Balchik SFE Kotel SFE Belogradchik SFE Smiadovo SFE Belogradchik SFE Smiadovo SFE Vidin SFE Smiadovo SFE Sofia SFE Smiadovo SFE Sofia SFE Tsonevo SFE Godech SFE Tsonevo SFE Samokov SFE Provadia SFE Samokov SFE Provadia SFE Samokov SFE Provadia GBS Aramliets SFE Provadia SFE Pirdop SFE Staro Oriahovo SFE Pirdop SFE Staro Oriahovo SFE Pirdop from 1953 to Also, data for 3 years (1968, 1970 and 1978) are generalized for the Regional Offices in Forests (Table 2). ROF Burgas including SFEs Aitos, Burgas, Zvezdets, Karnobat, Kosti, Malko Tarnovo, Novo Panicharevo, Sadovo, Sredets and Tsarevo, GBSs Gramatikovo, Nesebar and Ropotamo; ROF Varna SFEs Varna, General Toshevo, Dobrich, Provadia, Staro Oriahovo, Suvorovo and Tsonevo, GBSs Balchik, Tervel and Sherba; ROF Sofia SFEs Borovets, Botevgrad, Godech, Elin Pelin, Etropole, Ihtiman, 75

6 Koprivshtitsa, Pirdop, Samokov, Svoge and Sofia, GBSs Aramliets, Vitinia and Iskar; and ROF Shumen SFEs Varbitsa, Novi pazar, Omurtag, Smiadovo, Targovishte and Shumen, GBSs Palamara, Preslav and Cherni Lom. Out of 18 forestry enterprises, where the oak processionary moth was registered as a pest, 11 were in Eastern Bulgaria. Its presence there could be defined as stable, i.e. relatively high population number for e prolonged period, such as for instance is retained in the region of Balchik for an entire decade. The oak processionary moth has not been found in the southern parts of the country, with the exception of the coastal areas, which is a certain ground to surmise that probably in those regions the restricting factor is the higher temperatures and, respectively, the lower air humidity. The species was also absent in Central northern Bulgaria a region characterized by a more pronounced continental climate, i.e. with high summer and low winter temperatures and, on the other hand, with the lowest forestation; the oak forests are 5.6 ha/1 km 2. The presence of the species in the Sofia region has been confirmed by the report by Slivov (1990) of finding it at the foot of Vitosha mountain (Boyana residential district). Data on areas in Bulgaria attacked by oak processionary moth after 1953 No data for 1967 and 1969 have been found in the archival records referring to the period after (Table 3). The size of the areas attacked visualized in the chart below the Table delineate three peaks in the dynamics of its number for the 58-year period since 1953: first 1960, second 1970, and third The first two maximums, in 1960 and 1970, are close in their value of around 9 thousand ha, and differ substantially for the entire period under consideration. During the 1950s and 1960s, the chemical method of treating of forest ecosystems was used in Bulgaria on a mass scale, by applying low-selection pesticides. In these regions, the gypsy moth was periodically controlled. The total extermination of parasitic and predatory insects could be a rational hypothesis of such proliferation of the oak processionary moth. At the same time, out of 56 years for which reports have been found, no attack by this pest has been recorded for 15 (26.8%). Bearing in mind that the investigations have been carried out by an identical method, the subjective factor as to errors in records should be ruled out. The longest lull of 7 years ( ) in the numbers of the species could be explained by the control in 1970 (Table 4). Although the first treatments were by chemical substances, afterwards bacterial or hormonal substances were introduced, which have relative selectivity towards the useful entomofauna. Measures to regulate the numbers of the oak processionary moth in Bulgaria The reports of the forest protection services to the forest authority indicated the measures taken to restrict the number of the oak processionary moth. In attacks 76

7 Table 3 Information on areas infested by oak processionary moth in Bulgaria after 1953 Year Area, ha Year Area, ha Year Area, ha Year Area, ha No data No data ha Table 4 Treated areas against T. processionea in Bulgaria Year Region Area, ha Insecticide 1971 SFE Provadia Fostion, SFEkama nebelmitel 1973 ROF Burgas SFEkama tribufon 1975 ROF Varna and Burgas Entobacterin 1981 GBS Balchik Dipel 1982 GBS Balchik Dipel 1999 ROF Varna Custom larvo BT 2000 SFE Provadia Dimilin 2000 SFE Smiadovo Dimilin 77

8 of relatively small areas, mechanical control was frequently applied. Its essence is to exterminate the caterpillars when they were on the tree trunks by spraying them with naphtha, etc., or even burning them with a gasoline lamp. In case of high number of the pest on large areas, treatments were done by airplanes or helicopters. The data in Table 4 show that there are such cases only in the eastern part of the country. In 1984 there was also such control in the region of Vidin. According to data from the Forest Protection Bulletin of the Ministry of Forests and Forest Industry, however, the attack was mixed, the main insect pest being the gypsy moth (Lymantria dispar L.). Natural factors suppressing the number of oak processionary moth in Bulgaria Out of the biological factors suppressing the number of oak processionary moth, Weiser (1966) specifies diseases caused by nuclear-polyhedrosis virus and cytoplasmicpolyhedrosis virus, as well as successful artificial infection of the pest caterpillars by Bacillus thuringiensis Berliner We have not found, in the literature available to us, any reports of a disease on this insect pest in Bulgaria. From the parasitoids on the eggs of the oak processionary moth in Provadia Forest Enterprise, the land belonging to the village of Kiten, there have been isolated Anastatus bifasciatus (Geoffroy, 1785) (Hymenoptera: Eupelmidae) and Ooencyrtus sp. (Hymenoptera: Encyrtidae), the parasition by the first parasitoid being below 1%, and by the second only 1 individual has been found (Mirchev et al., 2003). The following parasitoids on caterpillars and pupae have been established in Bulgaria: - Meteorus versicolor (Wesmael, 1835) (Hymenoptera: Braconidae) (Atia, 1978; Zaikov, 1980) - Rogas (Aleiodes) rossicus Kokujev, 1898 (R. testaceus Spinola, 1808 auct.) (Hymenoptera: Braconidae) (Germanov, 1969, 1980) - From the pupae of oak processionary moth collected in the area of the village of Bozhuritsa, region of Vidin, Trenchev (1980) has isolated tachinae (Diptera: Tachinidae) Carcelia (Carcelia) laxifrons Villeneuve 1912; Platymyia nemestrina Meigen (1824) (Platymya fimbriata (Meigen, 1824) auct.); Platymyia westermani Zetterstedt, 1844 (Eumea linearicornis (Zetterstedt, 1844) auct.) and from the land belonging to the village of Voinitsa, the same region, Compsilura concinnata (Meigen 1824). Atia (1978) adds to this list three more tachinae, without specifying the habitats: Pales pavida (Meigen 1824); Zenillia libatrix (Panzer 1798) and Blondelia nigripes (Fallén 1810). Unfortunately, at these stages of the ontogenetic development of the species caterpillar and pupa no studies have been found providing data on the regulating effect of the parasitoids. 78

9 Conclusions The review of the data for an almost 100-year period convincingly confirms the thesis that, for the conditions of Bulgaria, ecological factors maintain, on the whole, the numbers of the oak processionary moth at a low level. Bearing in mind the abovementioned economic importance of this pest, it is necessary to study, in a more thorough and purposeful manner, the manifestation of these factors, which lead to the massive proliferation of the species in specific areas, or in specific years. REFERENCES Anonym Gnethocampa processionea. Forestry collection, (IX), IX, 1908, 157. (In Bulgarian). Atia, A. A Kinds and role of some parasitics insects of the Braconidae (Hymenoptera) and Tachinidae (Diptera) families on the lolyvorous forest insect. PhD Thesis, Abstract, Higher Forestry Institute, Sofia (in Bulgarian, English summary). B Caterpillars Forestry and fruit trees. Orallo, 11, (In Bulgarian). Baker, R. D. Caffier, J.W. Choiseul, P. De Clercq, E. Dormannsné-Simon, B. Gerowitt, O. E. Karadjova, G. Lövei, A.O. Lansink, D. Makowski, C. Manceau, L. Manici, D. Perdikis, A. P. Puglia, J. Schans, G. Schrader, R. Steffek, A. Strömberg, K. Tiilikkala, J.C. van Lenteren, I. Vloutoglou Scientific Opinion of the Panel on Plant Heath on a pest risk analysis on Thaumetopoea processionea L., the oak processionary moth, prepared by the UK and extension of its scope to the EU territory. The EFSA Journal, 491, Bozhkov, S Release occurred Cnethocampa processionea in Plovdiv. Mitteilungen der Bulgarischen Entomologischen Gesellschaft in Sofia, Band VI, p.12. Buresch, I Zweiter Beitrag zur Schmetterlingsfauna von Schlosspark Euxinograd, bei der Stadt Varna am Schwarzen Meer. Mitteilungen der Bulgarischen Entomologischen Gesellschaft in Sofia, Band VI, 12. Buresch, I., N. Karnojitski Biologishe Beobachtungen über Schmeterlinge in der Region von Varna. Mitteilungen der Bulgarischen Entomologischen Gesellschaft in Sofia, Band XII, Buresch, I., K. Tuleschkow Die horizontale Verbreitung der Schmetterlinge (Lepidoptera) in Bulgarien. II. Mitteilungen aus den Königlichen naturwissenschaftlichen Instituten in Sofia Bulgarien, vol. III, Forestry. National Statistical Institute. Sofia, (In Bulgarian). Dissescu, G., I. Ceianu Cercetari asupra bioecologiei omizii procesionare a stejarului (Thaumetopoea processionea) Bucuresti (in Romanian, Russian summary). Germanov, A Species composition, distribution and ecological notes on species of families Ichneumonide and Braconidae (Hymenoptera) in west part of Thracian lowland and some neighbour regions. PhD Thesis, University of Plovdiv, (In Bulgarian). Germanov, A A contribution to study of family Braconidae (Parasitica, Hymenoptera) in Bulgaria. Acta Zoologica Bulgarica, 14, (In Bulgarian, Russian and English summaries). Fauna Europaea Web Service Fauna Europaea version 1,3. Available online at www. Faunaeur. Org. Kosaroff, P Bericht über Krankheiten und Beschädigungen der Kulturpflanzen in Nord-Bulgarien während des Jahres Travaux de la Station agronomique de l Etat près de Roustchouk (Bulgarie), Imprimerie Zora Varna, II Bd, 1 Th., Lamy, M Contact dermatitis (erucism) producted by processionary caterpillars (Genus Thaumetopoea) J. of Applied Entomology, 110, Maksymov, J. K Thaumetopoea, Prozessionsspinner. In: Schwenke, W. Die Forsischädlinge Europas, Bd. 3. Parey-Verlag,

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