Cause of shoot dieback of blueberries in Northern Germany: Pathogenic fungi or winter frost damage? | Cause of shoot dieback of blueberries in Northern Germany: Pathogenic fungi or winter frost damage?
2013
Weber, Roland W.S. | Entrop, Alfred-Peter
In the summer of 2010 and during the following two seasons, a twig dieback of blueberries (Vaccinium corymbosum) was observed in southern Lower Saxony especially in younger plantations of the variety ‘Duke’. The sudden onset of a chlorosis and necrosis of individual twigs was associated with a destruction of the vascular cambium and with longitudinal streaks of brown discolourations in the xylem tissue deposited during the previous year. New shoots were often formed from the intact roots and from regions of older twigs located immediately above the soil surface. Potentially pathogenic fungi, including Godronia cassandrae, Phomopsis spp., Diplodia seriata, Pestalotiopsis sp., Paraconiothyrium sporulosum, Colletotrichum acutatum, Fusarium avenaceum and F. lateritium, were found sporadically on dead twigs, each fungus being present in 6 or fewer of the 12 plantations surveyed. Winter frost damage of xylem tissues was determined to be the main cause of the disease, facilitated by a delayed termination of vegetative growth which led to a lack of winter hardiness at the time-point of the first serious frost events.
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