Silva Balcanica, 12(1)/2011

DISTRIBUTION OF THAUMETOPOEA PROCESSIONEA (L.) IN

Plamen Mirchev, Georgi Georgiev Forest Research Institute – 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 . Data on the volume of attacks by oak processionary moth have existed since 1953. 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 – 2000. 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 Mass attacks by this pest have been registered in a number of European countries – , Italy, , Poland, France, , 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 (1953-2010); 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 3 871 447 ha, out of which 1 330 126 ha coniferous, and 2 541 321 ha deciduous. The surface area of the pure oak forests is 1 043 020 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 1 050 850 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 km2 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 Table 1 Distribution of oak forests in Bulgaria

Regions of Bulgaria Area, Distribution of oak forests 2 (1) Area, ha 2 Name Including districts with centres km (2) % ha/1 km North-Western , Montana, 10 596 75 440 7.2 7.1 , , , North Central 15 150 84 698 8.1 5.6 Ruse, , , North-Eastern 22 910 175 916 16.9 7.7 , , , Varna Sofia, , , South-West 14 646 183 728 17.6 15.5 , , , South Central , , 27 512 296 941 28.5 10.8 South-East , , 20 331 226 297 21.7 9.0 Total for Bulgaria 111 145 1 043 020 100.0 9.4 According to data: http://bg.guide-bulgaria.com/bg_Area_Sizes.aspx According to data: (Forestry...1992).

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 of Bulgarovo. Ala-tepe is a site 16 km south of Burgas, on the land belonging to the village of Rosen, the municipality of . 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 E of Greenwich 23 24 25 26 27 28

R O M A N I A

44 Vidin r 44 e

D a n u b e R i v

A

I

B

Belogradchik

R

E

S Shumen Varna 43 Tsonevo 43 Staro Smiadovo Sofia Aramliets Oriahovo Kotel Sliven Burgas

Samokov

A

I

Novo Panicharevo N

Plovdiv

42

O

42 D

Kosti E

Y K E C Black R 50 km

A U T Sea

M G R E E C E

23 24 25 26 27 28

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 ) in 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 . 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 Table 2 Information on regions infested by oak processionary moth in Bulgaria after 1968 Area, Region Year Area, ha Region Year ha ROF Varna 1968 2368.9 SFE Staro Oriahovo 1982 120.0 ROF Varna 1970 6873.1 SFE Staro Oriahovo 1983 98.0 ROF Shumen 1968 1348.0 SFE Staro Oriahovo 1985 230.0 ROF Burgas 1970 2546.0 SFE Staro Oriahovo 1988 110.0 ROF Sofia 1978 225.0 SFE Staro Oriahovo 1990 30.0 SFE Varna 1984 26.5 SFE Kosti 1994 21.7 SFE Varna 1999 1107.5 SFE Tsarevo 2000 360.0 SFE Varna 2010 2316.7 SFE Tsarevo 2007 332.4 GBS Balchik 1981 340.0 SFE Tsarevo 2009 244.6 GBS Balchik 1982 340.0 SFE Tsarevo 2010 60.1 GBS Balchik 1984 9.8 SFE Novo Panicharevo 2004 33.1 GBS Balchik 1985 140.0 SFE Novo Panicharevo 2005 98.7 GBS Balchik 1986 10.0 SFE Novo Panicharevo 2006 115.6 GBS Balchik 1988 22.0 SFE Novo Panicharevo 2007 38.8 GBS Balchik 1990 20.0 SFE Karnobat 2000 334.0 GBS Balchik 1991 30.0 SFE Kotel 2000 39.3 SFE Belogradchik 2003 90.0 SFE Smiadovo 1998 13.0 SFE Belogradchik 2005 290.0 SFE Smiadovo 2000 682.4 SFE Vidin 2001 90.0 SFE Smiadovo 2004 4.0 SFE Sofia 1998 126.1 SFE Smiadovo 2010 53.1 SFE Sofia 2006 6.6 SFE Tsonevo 2000 264.5 SFE Godech 1998 90.1 SFE Tsonevo 2010 81.9 SFE 1979 100.0 SFE Provadia 1998 56.7 SFE Samokov 1980 35.0 SFE Provadia 1999 370.7 SFE Samokov 1982 22.0 SFE Provadia 2000 1429.0 GBS Aramliets 2005 52.0 SFE Provadia 2010 69.3 SFE Pirdop 2005 41.0 SFE Staro Oriahovo 1980 130.0 SFE Pirdop 2006 4.0 SFE Staro Oriahovo 1981 315.0 SFE Pirdop 2010 2.0 from 1953 to 1967. 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, , Novo Panicharevo, , and Tsarevo, GBSs Gramatikovo, and ; ROF Varna – SFEs Varna, , Dobrich, Provadia, Staro Oriahovo, and Tsonevo, GBSs Balchik, and Sherba; ROF Sofia – SFEs , , Godech, , , ,

75 , Pirdop, Samokov, and Sofia, GBSs Aramliets, Vitinia and ; and ROF Shumen – SFEs , Novi pazar, , 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 ofthe 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 km2. 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 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 – 2000. 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 (1971-1977) 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 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 1953 500.0 1968 3716.9 1983 98.0 1998 285.9 1954 600.0 1969 No data 1984 36.3 1999 1478.2 1955 550.0 1970 9419.1 1985 370.0 2000 3591.0 1956 580.0 1971 0.0 1986 10.0 2001 3251.4 1957 540.0 1972 0.0 1987 0.0 2002 2027.4 1958 520.0 1973 0.0 1988 132.0 2003 1263.2 1959 975.0 1974 0.0 1989 0.0 2004 37.1 1960 8020.0 1975 0.0 1990 50.0 2005 481.7 1961 2848.0 1976 0.0 1991 30.0 2006 126.2 1962 2000.0 1977 0.0 1992 0.0 2007 370.9 1963 160.0 1978 225.0 1993 0.0 2008 0.0 1964 160.0 1979 100.0 1994 21.7 2009 244.6 1965 1060.0 1980 165.0 1995 0.0 2010 2583.1 1966 1020.0 1981 655.0 1996 0.0 1967 No data 1982 482.0 1997 0.0 ha 10000

5000

0

3 5 7 9 1 3 5 7 9 1 3 5 7 9 1 3 5 7 9 1 3 5 7 9 1 3 5 7 9

5 5 5 5 6 6 6 6 6 7 7 7 7 7 8 8 8 8 8 9 9 9 9 9 0 0 0 0 0 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2

Table 4 Treated areas against T. processionea in Bulgaria

Year Region Area, ha Insecticide 1971 SFE Provadia 1215.0 Fostion, SFEkama nebelmitel 1973 ROF Burgas 200.0 SFEkama tribufon 1975 ROF Varna and Burgas 845.0 Entobacterin 1981 GBS Balchik 300.0 Dipel 1982 GBS Balchik 340.0 Dipel 1999 ROF Varna 370.7 Custom larvo BT 2000 SFE Provadia 1356.5 Dimilin 2000 SFE Smiadovo 682.4 Dimilin

77 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 cytoplasmic- polyhedrosis virus, as well as successful artificial infection of the pest caterpillars by Bacillus thuringiensis Berliner 1911. 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 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 above- mentioned 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

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79 Marinov, M., K. Kostadinov, G. Popov, V. Stiptsov, H. Bozhinov, D. Dinev, D. Denev, S. Horozov. 1995. Oak forest in Bulgaria. – Sofia, Zimizdat, 254. (in Bulgarian,h Russian and English summaries) Mirchev, P., G. Tsankov, Y. Petrov. 2003. Study of some aspects of the bioecology of the oak processionary moth (Thaumetopoea processionea (Linnaeus, 1758) (Lepidoptera: Notodontidae) in North-east Bulgaria. – Silva Balcanica, 3 (1), 5.10. Mitrev, Y. 1894. Forestry. Sofia, 409. (In Bulgarian). Slivov, A. 1990. Butterflies from the superfamilies Bombycoidea, Sphingoidea and Noctuoidea (Insecta, Lepidoptera) from Vitoša. – Fauna of Southwestern Bulgaria, Part 3, 185-207. (In Bulgarian, Russian and English summaries). Tchorbadjiev, P. 1915. Contribution á la fauna des Macrolepidoptera du district de Burgase. –Reports of the Bulgarian Academy of Sciences, V, 1-45. (In Bulgarian). Trenchev, G. 1980. Parasite species of the subfamilie Exoristinae (Diptera, Tachinidae) in Bulgaria. – Plant science, 5, 121-126. (In Bulgarian, Rissian and English summaries). Zaikov, A. 1980. Study on the Genera of the Braconidae family (Hymenoptera) in the Rhodope Mountains. – Entomophags and their application in biological control, Sofia. 35-37. (In Bulgarian, English summary). Weiser, J. 1972. Microbiological methods control pest insects. Kolos, Moscow, 640. (In Russian).

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