02303nas a2200181 4500008004100000022001400041245010400055210006900159260002900228300001400257490000700271520172200278100001702000700001202017700002202029700001502051856005502066 2011 eng d a1439-032900aA twig blight of understorey European beech (Fagus sylvatica) caused by soilborne Phytophthora spp.0 atwig blight of understorey European beech Fagus sylvatica caused bBlackwell Publishing Ltd a493–5000 v413 a

During and after prolonged periods of rainfall in late spring, blighted young twigs of European beech (Fagus sylvatica) were frequently observed in several beech stands in south-western and southern Germany. Long and short shoots of young understorey trees or lower branches up to 1.5 m above the soil level were affected. Symptoms also occurred regularly on twigs in heights up to 2 m and more above the ground. Necroses usually expanded within the current year’s tissue and often also reached into the previous year’s wood. Ponding rain water in the stands or along forest roads or open soil seemed to promote the disease. Of a total of 54 symptomatic twigs collected in four stands, 37 revealed Phytophthora isolates, of which 33 were P. plurivora and four were P. cambivora. Both species caused extensive lesions on beech twigs in laboratory pathogenicity tests. Patterns of the disease indicated that these pathogens, generally considered soilborne species, in most cases are transmitted from the soil to above-ground parts of the trees via rain splash. In larger heights, however, other vectors such as snails might be responsible for transmission. Although Phytophthora spp. are well known as causal agents of seedling blight as well as root and cambium rot and aerial bleeding cankers of mature beech, to our knowledge this is the first report of a twig blight in beech associated with soilborne Phytophthora spp. In particular in periods of high precipitation, this disease might pose an additional threat to Central European beech forests, especially endangering the success of artificial and natural regeneration of beech in affected stands.

1 aNechwatal, J1 aHahn, J1 aSchönborn, A1 aSchmitz, G uhttp://dx.doi.org/10.1111/j.1439-0329.2011.00711.x