Uszkodzenia liści wierzby powodowane przez chrząszcze – obserwacje terenowe

Abstract

There is a big number of beetle species feeding on willow leaves. The aim of the study was to describe the damage to leaf blade caused by imagines of: Crepidodera aurata, Chrysomela populi, Chrysomela vigintipunctata, Lochmaea capreae, Pachybrachis sp. (Chrysomelidae); Phyllopertha horticola i Anomala dubia (Scarabaeidae), Lepyrus palustris, Polydrusus spp. and Phyllobius spp. (Curculionidae). Data were collected at three plantations (Salix viminalis and its hybrids) and in one natural site (different species of narrow-leaved willows), in the years 2011–2018. For each insect taxon: date of feeding, age class of suffered leaves, shape and depth of the damage, and its placement on the leaf blade were determined. All the studied beetles were feeding on young leaves in different stages of development. Sometimes they used leaves folded by Earias clorana larvae. Damage occurred during whole growing period of the willow. The most common kind of injuries were irregular holes, varying in size, sharp and location. C. aurata also bit out minute “windows” (surface feeding) in the leaf blades. Holes made by Pachybrachis spp. always occur-red in a line, between main vein and leaf edge. Damage of willow caused by Polydrusus and Phyllobius are described in literature as small semicircular notches on leaf edges (margin feeding), but in the case of gradation in Sa-dłowice in 2014, the apical parts of the young leaves were completely eaten. The observation showed, that on production willow plantations, injuries un-described so far in guidebooks for farmers, could occur.