Glavendekić & Mihajlović: Exposure of noctuid and geometrid development stages in oak forests EXPOSURE OF NOCTUID AND GEOMETRID DEVELOPMENT STAGES IN OAK FORESTS Milka M. Glavendekić, Ljubodrag S. Mihajlović Faculty of Forestry University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia (e-mail: [email protected]) Abstract The research was carried out in the period 1985-2005 in oak forests in Serbia. During the research of winter moths in oak forests of Serbia we recorded 9 outbreaking winter moth species: Colotois pennaria L., Agriopis aurantiaria Hbn., Erannis defoliaria Cl., Alsophila aescularia D.& Sch., A. aceraria D.& Sch., Operophtera brumata L., Apocheima pilosaria D.& Sch., Agriopis leucophaearia D.& Sch., A. marginaria F. The most significant noctuids are Orthosia spp. There are 38 parasitoids of the winter moths recorded and they fall into the families Braconidae, Ichneumonidae, Eulophidae, Torymidae, Trichogrammatidae, Scelionidae and Tachinidae. Egg parasitoids were recorded at 3 localities: Brankovac, Mala Moštanica and wide area of National Park Djerdap. Hyperparasitoids of winter moths in Serbia have also been studied. We recorded altogether 12 species of winter moth hyperparasitoids. The method of exposure was applied in egg and larva stages. While total parasitism in the natural population varies between 12.50-28.57 %, in the exposed conditions there were between 27.31-43.75 % parasitized caterpillars were recorded. The method of host exposure could be suitable for the local increase of abundance of parasitoids of winter moth eggs, larvae and pupae. Keywords: Defoliators, oak, Geometridae, Noctuidae 1. Introduction In Serbia forests cover about 2,313,000 ha, or 26.2 % of the whole territory. They are managed by the State Enterprises for Forest Management, PE “Srbijašume” and PE “Vojvodinašume”. The average standing volume is 101.6 m3/ha. The average annual increment is 2.70 3 /ha and total annual increment 6.18 million m3. Forests are mainly state and socially owned. The state owns 1.38 million ha (56.2 %) of forest area. Under private ownership is 1.17 million ha (43.8 %) of Serbian forests. The average size of private forest holdings is about 0.5 ha (Glavonjic et al., 2005). As for the stand composition, according to the Ministry of Agriculture, Forestry and Water Management, pure deciduous stands are dominant (60%). Mixed deciduous stands occupy 30%, pure coniferous stands 5%, mixed deciduous-coniferous stands 3% and mixed coniferous stands 2%. There are the following forest complexes in Serbia: alluvial hygrophilous forests (0.11%), xerothermophilous Hungarian oak-Turkey oak forests (15.41%), xeromesophilous sessile oak- Turkey oak-hornbeam forests (12.49%), mesophilous beech forests and beech coniferous forests (52.58%) and thermophilous pine forests (12.92%). Beech is the main broadleaf species (47%) followed by oak (25%), poplar (1%), other broadleaves (16%), spruces (5%), pines (2%), fir (3%) and other conifers (1%). Damage in forests can be caused by fire. It varies from year to year. In 1990 almost 60% of damages were caused by fire. In 2000, 300 fires occurred and damaged 4,000 ha of forest. In IUFRO Working Party 7.03.10 Proceedings of the Workshop 2006, Gmunden/Austria 126 Glavendekić & Mihajlović: Exposure of noctuid and geometrid development stages in oak forests 1997 up to 40 % of damage in forests was caused by insects and diseases. The most severe dieback was recorded in oak forests 1983-1994. They were caused due to cumulative defoliations caused by insects and synchronous attack of pathogens and vascular fungi. More than 121 species of insects were identified as trophically related to oak (Quercus petraea (Matt.) Lieblein, Q. cerris L. and Q. frainetto Tenore) forests in the region of NP Đerdap. They belong to the orders Homoptera, Coleoptera, Diptera, Lepidoptera and Hymenoptera. The insects feed on or spend a part of their lives on the foliage, branches, in the stem, buds or proliferations of plant tissues that they cause themselves. The consequences of the damage are mostly insignificant for forest ecosystems and without an economic significance (53.33%). Somewhat more than 1/3 of insects are occasionally harmful (36.67%) and outbreaking, economically significant and dangerous insect pests in oak forests account for 10% of the identified species of phytophagous insects. The most important insect pests in oak stands are defoliators: Lymantria dispar L. (Lepidoptera: Lymantriidae), Tortrix viridana L., Aleimma loeflingiana L. (Lepidoptera: Tortricidae), Orthosia spp. (Lepidoptera: Noctuidae), Colotois pennaria L., Agriopis spp.., Erannis defoliaria Cl. Alsophila spp., Operophtera brumata L. and Apocheima spp. (Lepidoptera: Geometridae) (Glavendekić, 2002). The research on oak defoliators was carried out in the period 1987-2006 in oak forests in Serbia (Mihajlović & Glavendekić, 2006). The task of the research was to investigate qualitative composition of the winter moths: Colotois pennaria, Alsophila aceraria, A. aescularia, Agriopis aurantiaria, A. leucophaearia, A. marginaria, Operophtera brumata, Apocheima pilosaria, Erannis defoliaria (Lepidoptera: Geometridae) and noctuids: Orthosia cruda, O. incerta, O. munda, O. s tabilis, O. miniosa (Lepidoptera, Noctuidae). Their biology, population dynamics and natural enemies - especially parasitoids were studied. 2. Material and methods Investigations were done at the following sample plots at the localities: Brankovac (National Park Fruška Gora), Košutnjak, Mala Moštanica (Forest Estate Belgrade) and National Park Djerdap from 1985-2005. In addition to permanent sample plots, the study region was extended to several localities with different oak stands and ecological conditions, in order to obtain the most complete data on the winter moth population dynamics and on the complex of their parasitoids in Serbia. The method of exposure in nature was applied to eggs and larvae either by exposing the masses of eggs reared in the laboratory or by using sticky bands at the time of female activity. Females laid egg masses in bark crevices below sticky bands. The parts of the bark with eggs were cut and the samples were taken to the laboratory for rearing and processing. Sticky bands were also used for larval exposure in April and May. Sticky bands were placed at breast height, width 80-100 mm. During their return to the crown, the larvae aggregated on the stem and thus the exposure effect was achieved. The caterpillars at different stages were collected, packed in plastic bags or boxes with ventilation net and brought to the laboratory for individual rearing. IUFRO Working Party 7.03.10 Proceedings of the Workshop 2006, Gmunden/Austria 127 Glavendekić & Mihajlović: Exposure of noctuid and geometrid development stages in oak forests 3. Results 3.1 Parasitoids of the winter moths and noctuids There are 42 parasitoids recorded (Braconidae, Ichneumonidae, Eulophidae, Torymidae, Trichogrammatidae, Scelionidae and Tachinidae). The following egg, larval and pupal parasitoids were recorded in Serbia: Aleiodes gastritor (Thunb. 1822), Acampsis alternipes Brulle, 1846, Apanteles enephes Nixon, 1965, Protapanteles immunis Hal.,1834, Protapanteles sp., Cotesia hyphantriae Riley, 1886, Cotesia limbata Marshall, 1885, Cotesia jucunda Marshall, 1885, Cotesia spuria Wesmael, 1837, Cotesia congestus (Nees, 1834), Apanteles sp. (sensu lato) (Hymenoptera: Braconidae). Itoplectis alternans Grav., 1829, Netelia (B.) latungula Thom.1888, Aptesis jejunator Grav., 1807, Casinaria ischnogaster Thom. 1887, Casinaria moesta Grav., 1829, Phobocampe crassiuscula Grav.,1829, Phobocampe pulchella Thom., 1887, Phobocampe sp. 1, Phobocampe sp.2, Phobocampe sp.3, Ophion minutus Kriechb., 1879, Ophion ventricosus Grav., 1829, Agrypon flaveolatum Grav., 1807 (Hymenoptera, Ichneumonidae); Torymus sp., (Hymenoptera: Torymidae), Euplectrus bicolor (Swe., 1795), Eulophus larvarum (L., 1758) (Hymenoptera: Eulophidae), Trichogramma sp. (Hymenoptera: Trichogrammatidae), Telenomus minutus Ratz., Telenomus ? dalmanni Ratz., 1844 (Hymenoptera: Scelionidae), Phorocera obscura Fallén, 1810, Blondelia nigripes Fall., 1810, Compsilura conncinnata Meig., 1824, Phryxe magnicornis Zett., 1838, Phryxe nemea Meig., 1824, Phryxe vulgaris Fall., 1810, Peribaea apicalis R. – D., 1863, Peribaea fissicornis Str. 1909 (Diptera: Trichogrammatidae). Parasitoids of Noctuidae in Serbia are: Macrocentrus abdominalis F., Cotesia spuria Wesmael, Meteorus versicolor, M. scutellator Nees (Hymneoptera, Ichneumonidae), Phobocampe pulchella Thoms. (Hymenoptera, Ichneumonidae), Perilampus ruficornis (Hymenoptera, Perilampidae); Compsilura concinnata Mg., Blondelia nigripes Fall. (Diptera: Tachinidae). 3.2 Hyperparasitoids of the winter moths and noctuids The following hyperparasitoids of the winter moths are recorded in Serbia: Acrolyta rufocincta Gravenhorst, 1829, Gelis areator Panzer, 1804, Gelis sp, Bathythrix lamina Thomson, 1884, Astiphromma sp., Mesochorus sp., Brachymeria secundaria Ruschka,1922, Perilampus ruficornis (Fabricius, 1793), Habrocytus chrysos Walker, 1836, Tetrastichus sp., Pediobius foliorum Geoffroy in Fourcroy, 1785 and Pediobius sp. Fore some hyperparasitoids, winter moths have not been previously recorded as hosts: Acrolyta rufocincta Grav., Brachymeria secundaria Ruschka, Habrocytus chrysos Walk., Tetrastichus sp. Populations of parasitoids and hyperparasitoids were monitored in the culmination and in the post culmination phases in managed forests. The larva of hyperparasitoid hatches