Ash Dieback in Forests and Rural Areas—History and Predictions

Abstract

Ash trees are an important component of both forests and the countryside. Emerging new diseases like ash dieback poses new challenges to Fraxinus spp., which not only have to adapt to global warming but also defend themselves against new threats from pathogenic fungi and insect pests. A new species of fungus, Hymenoscyphus fraxineus, has arrived in Europe from Asia and has severely damaged shoots which alters the structure of ash tree crowns. While some older trees have survived, younger trees are dying en masse, so the only hope is that the surviving trees will produce a younger generation that may be more resistant to the new diseases. The fine roots of ash trees are also attacked by pathogenic oomycetes, and others by Armillaria spp. The current stressed condition of ash trees in Europe is exacerbated by a new threat from insects. Agrillus planipennis, emerald ash borer, migrating from the east (from near Moscow airport) towards the borders of the European Union, killing thousands of ash trees on its way. This raises the question of future prospects for ash cultivation in Europe. This article takes a closer look at the information described in the literature.

Use of Phosphite Preparations to Protect Ash Seedlings Fraxinus excelsior L. against Phytophthora spp. and Hymenoscyphus fraxineus Pathogens

“…This article deals with a current problem in Europe, namely, the phenomenon of ash dieback [1,2], the first symptoms of which were observed in 1992 in northeast Poland [3,4]; this concerned the death of seedlings in tree nurseries, young trees in forest plantations, and old trees in tree stands. The leaves were infected by the ascospores of the fungus, and, as a result, the entire shoots withered (Figure 1).…”