Symptoms
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Necrosis of the rims of leaves, drying out (rolling) of leaves, premature leaf shedding, beginning on the tips of the shoots and extending towards the stem; dieback of the crown, often visible only in the year following the drought; drop of shoots: Populus, Quercus; also shed of parts of the bark (Platanus.
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Impact
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The following tree genera are most susceptible: Betula, Acer pseudoplatanus, Carpinus betulus, Alnus, Picea and Larix. Drought effects vary depending on the time drought occurs: drought in spring causes symptoms often in the same year, damage of drought periods in summer usually become visible in the following year(s). Drought causes a general physiological weakening of the tree and a reduction in the assimilating tissues; intense stress – esp. with young trees, may cause death of the tree; increased risk of secondary invaders.
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Control
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solitary trees: watering, careful pruning
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Hosts |
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Maple;
Apple;
Birch;
Pear;
Beech;
Boxelder;
Douglas fir;
European mountain ash;
Edible chestnut;
English ivy;
Yew;
Oak;
Wild service tree;
Alder;
Ash;
Ex-Robinia;
Serviceberry;
Spruce;
Lilac;
Forsythia ;
Framire;
Ginkgo;
Tree-of-heaven;
European Hornbeam;
Dogwood;
Hazel;
Hemlock;
Elder;
Hophornbeam;
Pine;
Cherry;
Buckthorn;
Larch;
Thuja;
Privet;
Linden, Lime;
Magnolia;
Redwood;
Giant sequoia;
Mulberry;
Common whitebeam;
Common medlar;
Olive tree;
Poplar;
Bladdernut;
Plane;
Rhododendron;
Leyland cypress;
Rose;
Horse chestnut;
False Cypress;
Japanese Pagoda tree;
Spindle;
Holly;
Fir;
Southern Catalpa;
Elm;
Juniper;
Walnut;
Willow;
Common grape wine;
Hawthorne;
Cedar;
Hackberry;
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Affected plant parts
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Leaf;
Needle;
Root;
Shoot/Twig/Branch;
Stem;
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