DIGITALNA ARHIVA ŠUMARSKOG LISTA
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M. Glavendekić: PARASITOIDS AND HYPERPARASITOIDS OF ERANNIS DEFOLIARIACL. ... Šumarski list br. 7–8, CXXXIV (2010), 403-410 dominant at the locality Miroč, eggs of this species were less parasitized (8.11%). Egg parasitism of A. aurantiariawas lower - only 5.4%. Parasitized eggs are brown, so they can be readily differentiated from the eggs parasitized by waspsTrichogramma sp. Thedissection of dead eggs revealed the presence ofT. minutuslarva in them. In the Forest units Zlatica, Boljetinska reka and Mala Moštanica the waspsTrichogramma sp.(Hymenoptera: Trichogrammatidae) were reared from winter moths eggs. Parasitized eggs are distinguished by their almost black colour. In this way, we can assess the parasitism even after the eclosion of parasitic wasps.The winter moth eggs were parasitized between 16.33% at Boljetinska Reka, compartment 44, to 33.95% at Zlatica, compartment 96. It was found out that the majority of eggs died from other causes (e.g. predators).At Zlatica, compartment 59, the total mortality of eggs DISCUSSION Many authors give the data on population dynamic of E. defoliaria (Patočka et al.,1968; Glavendekić, 1988, 1999). During our study, mottled umber moth was recorded in all localities, most often in a lower population density except in East Serbia, where it was dominant compared to the populations of other early-season defoliators. Winter moth population dynamics has been studied in different forest types. Based on our own data and literature, it is evident that frequent outbreaks of 9 winter moth species are of chronic type and characteristic for the following forest types: forest ofTurkey oak and sessile oak (Quercetum petraeae-cerris) on brown and les sive brown soil on serpentinite at the locality Brankovac; forests of sessile oak (Quercetum montanum typicum) on acid brown soil in the locality Porečke šume, compartment 54 f; in the forest of Hungarian oak andTurkey oak with Eastern hornbeam (Quercetum frainetto-cerris carpinetosum orientalis) on dystric and eutric brown soils on Bukovik; in the association Orno-Quercetum pubescentis- virgilianae in Košutnjak and in the artificially established stand of mixed oaks at Mala Moštanica. Plantations of pedunculate oak mixed with hornbeam in forest unitVisoka šuma Lošinci are also under threat of winter moths outbreaks. Winter moths occur regularly, but as a rule there are no outbreaks in the forest of sessile oak, Turkey oak and hornbeam (Carpino-Quercetum petraeae-cerris) onbrown forest soil and lessive brown forest soil. The study of parasitoids and hyperparasitoids ofE. defoliariashows that parasitic wasps fam. Braconidae are not narrowly specific for theE. defoliaria The fauna of parasitic wasps in the fam. Ichneumonidaeisrelatively poor also if compared to the fauna of other European countries, Slovakia and the former was 58.49%. In Zlatica, compartment 96 egg mortality was 44.65%. The level of egg parasitism of winter moths in natural population in the management unit Zlatica, compartment 59 was 33%. Larval eclosion was recorded from 41.51% of eggs, whereas 25.47% eggs died during the embryonic development. In the Forest unit Zlatica, compartment 96, the parasitized eggs were almost 34%.The mortality during the embryonic development was 10.7%According to the report of the Diagnose-forecasting service, a mass occurrence of winter moths was forecast for the spring in 1992 in these compartments, but it failed.The efficiency of egg parasitoids in the management unit Boljetinska Reka, compartment 44, was somewhat lower, there were altogether 16.33% parasitized eggs. Egg mortality during embryonic development was 14.28%. – Rasprava USSR (Herting, 1965, 1976; Čapek, and Čepelak, 1981;Čapek,1985). One of the reasons is that winter moths in the study period were in pre-culmination, culmination or in the first post-culmination years, when parasitoid populations in the fam. Ichneumonidaeare usually low.They dominate in the phase of latency, while in the culmination phase they retreat before Tachinidae. Eulophus larvarum is the most frequent and the most numerous representative of parasitic wasps in the superfamily Chalcidoidaea.In the conditions of winter moth outbreaks, it is a dominant representative of parasitic Hymenoptera.In the host culmination phase, this species also showed a great upswing of abundance. Egg parasitoids Trichogramma sp. and Telenomus minutushave been described.The research was performed in the entire study area, but egg parasitoids were detected only at the locality Mala Moštanica, Zlatica and Miroč. Egg parasitoidT. minutuswas so far recognized only as the parasitoid ofOrthosia miniosa(Lepi doptera, Noctuidae) (Kozlov and Kononova, 1983), and Operophtera spp.(Glavendekić&Gruppe,1992). Tachinidae are the most significant winter moth parasitoids on many localities. The dominance and frequency of B. nigripes, P. nemea are expected and in harmony with the results of the studySisojević and Čepelak,(1998).TachinidsP. magnicornis, andP. fissicorniswere found individually. In the study of population dynamics of early-season defoliators in the Management unit Kožica in the period 1992–1994, a high population density was recorded in 1992, and already in the following year there was a drastic decrease of population density.This was caused, first of all by caterpillar parasitoids, which reduced ca. 67%.The most represented parasitoids wereTachinidae. On that occa |