Larval feeding of Cydalima perspectalis on box trees with a focus on the spatial and temporal distribution

Abstract

The box tree moth Cydalima perspectalis is an invasive pest on box trees originating from Eastern Asia which spread throughout Europe. We assessed the efficacy of photo-eclectors (emergence boxes) for the detection of its larvae. We also investigated their spatial distribution on the hosts and the spatial and temporal distribution of the leaf damage caused by this pest in Slovakia. Our results showed non-uniform vertical distribution of the overwintering larvae and leaf damage on the trees. The larval abundance in the spring was significantly affected by the height of the branches above the ground. During spring, the larvae occurred most abundantly in the upper parts of the trees. The leaf damage was greatest in the lower parts throughout the growing season. During the progress of the infestation, the development of the damage in the lower and middle parts was similar. In the upper part, the initial increase in the damage was slow, but accelerated four months before the complete defoliation. The field estimation of the proportion of damaged leaves and the accurate assessment based on counting the damaged leaves suggest a consis­tency between these estimates. Hence, a quick field estimation of the leaf damage may be utilised by horticultural practices.