Symptoms
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Cankers on stems of maples: initially an insignificant bark necrosis (flattened, slightly dark, sunken area with an elevated border, bark underneath dead). Winthin a couple of years this develops into a big, in the centre cracking, characteristically unilateral canker, which can cause a slight stem deformation. Fruiting bodies (perithecia) appear only after 5-8 years as blackish, brittle and flat „coverage“ at the border of the necroses in dead tissue. There are several other cankers on maple, for a serious diagnosis identification by a special lab is essential.
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Impact
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The Eutypella canker disease origins from North America, occurring there on various maple species. It has been found in Europe recently (Slovenia 2005). Eutypella parasitica is an ascomycete, which spreads by spores developing in high numbers in the perithecia. The fungus enters the tree by its spores via small wounds on the stem and on branches. The diseased trees commonly survive many years, but they become susceptible to breakage or to secondary invaders (rot).
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Control
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As with all quarantine-organisms all has to be done to keep the disease from further spreading in Europe. The primary and main challenge is to report stem cankers of maple (all maple species!) as soon as possible to local authorities (disctrict), the plant protection service or the BFW. After identification by specialists the diseased trees have to be felled and the stems have to be removed from the stand (see also leaflet).
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Hosts |
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Maple;
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Affected plant parts
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Stem;
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