Estudi de la capacitat de rebrotada del boix (Buxus sempervirens) afectat per la papallona del boix (Cydalima perspectalis) a la comarca de la Garrotxa

Abstract

The box tree moth, Cydalima perspectalis, is an invasive alien species of the Crambidae family. Since it was accidentally introduced in Catalonia it has rapidly spread causing significant damage to the box tree (Buxus sempervirens) with severe and consecutive defoliations that have left the box tree population of natural forests and urban areas in a critical situation. The first data of the arrival of C. perspectalis in Catalonia was in 2014, specifically in la Garrotxa although it wasn’t until 2017 that the great impact of this species on natural habitats was noticed. In order to contribute to improve the ecological knowledge of the box tree moth, the condition of the box trees was studied to determine the affectation degree and estimate the capacity of survival that they present. From the cartography of the habitats of Catalonia, a map has been drawn up where the Garrotxa habitats have been selected with more box tree presence. In these habitats 10 plots have been chosen and in each of them 15 box trees have been marked. The samplings were performed in 2019, one in summer, between July and September, when caterpillars are more active and butterflies show their highest flight peak, and another in winter, in December, when larvae are in a state of hibernation and box trees don not suffer defoliation. Comparing the two samples, results show that on the one hand, most of the plots studied are in a deterioration in the state of the box trees, both in the number of sprouts and the distribution they present in the plant, causing its concentration at the base of the box tree. On the other hand, it has been observed that there are plots showing an improvement in the sprouting, which can be caused by a delayed affectation. In short, plot averages show significant differences between them, possibly due to variation in sampling dates