Parasitoids and Predators of Ips typographus (L.) in Unmanaged and Managed Spruce Forests in Natural Park Apuseni, Romania

Abstract The last time span, of protected areas of forest ecosystems established raise of a variety of problems regarding frequency and intensity of the attack carried out by the rich pest complex affecting the trees' state of health. The current legislation forbids the application of pests control measures which can affect the biodiversity of these ecosystems. Species belonging to the useful entomofauna may interfere in the decrease of pest populations in these areas. The study of the parasitoid and predator complex has thus become a very topical research field, and these type of studies were carried out in Natural Park Apuseni, Romania. With the aim to identify present parasitoids and predators, 24 spruce logs provided from physiological weakened trees of 20-25 cm diameter and 1 m length were placed in 6 locations, in order to be populated by the spruce bark beetle Ips typographus (Linnaeus) as a trophic base of useful insect species. After its infestation the wood material was put in eclectors and analyzed weekly for the spruce bark beetle Ips typographus, its parasitoids and predators. After examining collected biological material, 6 parasitoid species were identified which determined a 4.8% parasitization in unmanaged and 2.3% parasitization in managed forests. The best represented Hymenopteran parasitoids were Roptrocerus xylophagorum (Ratzeburg) and Rhopalicus tutela (Walker). The found Coleopteran predators were from 12 species, which belong to 4 families. The most captures were of the species Nemosoma elongatum (Linnaeus), representing 50.3% of the total captured predators and Rhizophagus cribratus (Gyllenhaal), representing 9.5% of the captures