DISTRIBUTION of THAUMETOPOEA PROCESSIONEA (L.) in BULGARIA Plamen Mirchev, Georgi Georgiev Forest Research Institute – Sofia
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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 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 – 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 (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 Vidin, Montana, Vratsa 10 596 75 440 7.2 7.1 Lovech, Pleven, Gabrovo, North Central 15 150 84 698 8.1 5.6 Veliko Tarnovo Ruse, Razgrad, Targovishte, North-Eastern 22 910 175 916 16.9 7.7 Shumen, Silistra, Dobrich, Varna Sofia, Pernik, Kyustendil, South-West 14 646 183 728 17.6 15.5 Blagoevgrad Plovdiv, Pazardzhik, Smolyan, South Central Haskovo, Kardzhali, 27 512 296 941 28.5 10.8 Stara Zagora South-East Burgas, Sliven, Yambol 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 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 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 Balchik S Shumen Varna 43 Godech Provadia Tsonevo 43 Staro Smiadovo Sofia Aramliets Oriahovo Pirdop Kotel Sliven Karnobat 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 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 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