The Predictive Research of Lymantria Monacha Species within Natura 2000 Cusma Site

Abstract

SYMMARY Lymantria monacha is one of the most dangerous butterfly species, af fecting softwood in general ( spruce, pine, fir, larch, duglas ), but also hardwood in particular. The l arvaes attack in the beginning the young buds just after their fr uit outlets, ending the attack by eating, total or partial, the needles. The species has a large pr opagation, often leeding to the drying of trees, causing up to 60% defoliation (Oltean et. al l, 2003). For the quantitative evaluation of Lymantria monacha population within Natura 2000 Cusma site, sex attractant pheromone races have been placed during 2008, within the terr itory of Tihu ţa-Colibiţa, Josenii Bârg aului and Bistri ţa Bârg aului Forest Districts (Proorocu et. all, 2007, 2009). Within Tihu ţa-Colibiţa Forest District territory, 27 pheromone races hav e been installed, distributed both in the young and in the mature bru shes. The medium number of individuals/race was 30 and the maximum number of individuals (101) has been collected by race number 4, race that has been places within a 7 5 years old forest, formed by a mix of spruce, fir and beech, with a spruce predomination. The recorded annual dynamic is characteristic for the species that develop only on e generation per year, with a numerical maximum in the beginning of August. Within Josenii Bârg aului Forest District territory, 58 pheromone races have been installed in an over 60 years old mature brush, a m edium number of 18 individuals/race and a maximum number of 43 individuals/race being recorded. Within Bistri ţa Bârg aului Forest District territory, 94 pheromone races have been in stalled in an over 60 years old mature brush, the medium number of Lymantria monacha individuals/race being 47, and the maximum one, 99. The achieved data allows us to conclude the fact that, within Natura 2000 Cusma Site, the attack of Lymantria monacha species is a moderate one, no other detection methods beeing necesary.