Description of Intra-Annual Changes in Cambial Activity and Differentiation of Secondary Conductive Tissues of Aesculus hippocastanum Trees Affected by the Leaf Miner Cameraria ohridella

Abstract

Aesculus hippocastanum trees are commonly infested by the leaf miner Cameraria ohridella, whose larval activity causes the destruction of the leaf parenchyma and induces defoliation. Pest attacks result in, e.g., production of smaller fruits and tree re-flowering in autumn. Concerning pest influence on stem structure only scarce information of narrower annual growth rings of wood has been published. Therefore, we determined the effect of the presence of the leaf miner infestation on intra-annual cambial activity and on differentiation of conductive tissues. These data were compared with phenological phases and pest activity. Pest feeding resulted in changes in onset, cessation and duration of cambial divisions, and differentiation of secondary xylem. The duration of cambial activity was about a month shorter in heavily infested trees and was connected with premature tree defoliation. Affected trees were characterised by a reduction in cambial divisions and earlier cessation of wood differentiation resulting in narrower wood rings. Furthermore, the infested trees exhibited altered wood structure, with more vessels of smaller diameters, however these changes did not affect its theoretical hydraulic conductivity. Interestingly, pest attack did not influence secondary phloem differentiation. The probable influence of long-term infestation on tree growth and condition was discussed.

The Secondary Metabolites Profile in Horse Chestnut Leaves Infested with Horse-Chestnut Leaf Miner

“…Extensive brown-yellow spots on leaves as well as rapid wilting and premature fall of leaves before the end of the growing season are the external symptoms of C. ohridella (horse-chestnut leaf miner) foraging [ 7 , 8 , 9 ]. As a result of infestation by many (5–7) generations of larvae of the pest, the tree is severely weakened, the photosynthetic efficiency declines, the intensity of flowering and the weight and size of fruit and seeds are reduced, and the size and vitality of developing seedlings decrease [ 10 , 11 , 12 ].…”

Seasonal dynamics of cell-to-cell transport in angiosperm wood

“…Transverse and longitudinal sections (8 µm thick) were prepared using a rotary microtome (Leica RM 2135, Germany) and stained with Alcian Blue-Safranin O solution, mounted in Euparal, and observed under a bright-field microscope with a polarization adapter. The cambial activity and processes of wood formation in ash and maple were analysed according to Myśkow et al . (2021) .…”

Tree diversity and density affect damage caused by the invasive pest Cameraria ohridella in urban areas

“…The larvae mine the leaves, creating brown lesions that can eventually cover the entire leaf area and cause early defoliation. Although mature trees are rarely endangered by such defoliations, they can result in serious loss in radial growth and aesthetic values (Jagiełło et al, 2019;Myśkow et al, 2021), while mortality may occur in highly infested young trees (Salleo et al, 2003). Past studies in urban areas have shown that C. ohridella can be parasitized by insects (Girardoz, Quicke, et al, 2007a;Grabenweger et al, 2010;Volter & Kenis, 2013) and preyed by birds (Grabenweger, Kehrli, et al, 2005b).…”