Current status of the distribution of European mistletoe (Viscum album L.) in Zhytomyr Polissia

Abstract

Background. European mistletoe (Viscum album L.) is a hemiparasitic, autotrophic plant, which is an integral part of natural and urbanized ecosystems of Ukraine, in particular Zhytomyr Polissia. V. album is considered to be an aboriginal species which is largely responsible for the deterioration of the sanitary condition of woody plants. In particular, it causes their premature drying, a sharp decrease in the intensity of growth and yield of fruit. This study pursues the following goals: 1) to identify the species of trees affected by V. album and which ones it prefers in the conditions of Zhytomyr Polissia; 2) to study the biology of the development of V. album in the conditions of the region; 3) analysis of the degree of damage to trees by V. album using the coefficient of complex assessment. Materials and Methods. The reconnaissance method was used to determine the distribution of V. album, the type of damage and the intensity of damage to tree plantations and the degree of tree damage by mistletoe was determined using the coefficient of comprehensive damage assessment (Ccda). Results and Discussion. It was found that out of the total number of affected trees, B. pendula (27.13 %), R. pseudoacacia (17.04 %) and P. tremula (11.13 %) were the most commonly infested by V. album in the region. At the same time, 46 % of the trees are slightly damaged, 31 % are moderately damaged and 23 % are insignificantly dama­ged. It was found that without human intervention, the number of populations and the number of V. album tend to increase. Conclusions. On the territory of Zhytomyr Polissia, V. album has entered the cate­gory of invasive plants. V. album was detected on 20 tree species, of which the number of trees affected by V. album reached 41.54 % of the total number of the examined trees. The vast majority of V. album populations (61 %) are growing. The largest numbers of V. album shrubs were recorded on trees aged 60–80 and 80–100 years, accounting for 23 % and 25.13 % of the total number of trees infested by V. album, respectively.