02329nas a2200205 4500008004100000022001400041245010500055210006900160260002900229300001400258490000700272520168900279100002001968700001501988700001802003700001702021700001802038700001202056856005502068 2011 eng d a1439-032900aPhytophthora root and collar rot of mature Fraxinus excelsior in forest stands in Poland and Denmark0 aPhytophthora root and collar rot of mature Fraxinus excelsior in bBlackwell Publishing Ltd a510–5190 v413 a

In recent years, Common ash (Fraxinus excelsior) throughout Europe has been severely impacted by a leaf and twig dieback caused by the hyphomycete Chalara fraxinea. The reasons for its current devastating outbreak, however, still remain unclear. Here, we report the presence of four Phytophthora taxa in declining ash stands in Poland and Denmark. Phytophthora cactorum, Phytophthora plurivora, Phytophthora taxon salixsoil and Phytophthora gonapodyides were isolated from rhizosphere soil samples and necrotic bark lesions on stems and roots of mature declining ash trees in four stands. The first three species proved to be aggressive to abscised roots, twigs and leaves of F. excelsior in inoculation experiments. Soil infestation tests also confirmed their pathogenicity towards fine and feeder roots of ash seedlings. Our results provide first evidence for an involvement of Phytophthora species as a contributing factor in current decline phenomena of F. excelsior across Europe. Specifically, they may act as a predisposing factor for trees subsequently infected by C. fraxinea. Phytophthora species from ash stands also proved to be aggressive towards a wide range of tree and shrub species commonly associated with F. excelsior in mixed stands. Although damage varied considerably depending on the Phytophthora species/isolate-host plant combination, these results show that many woody species may be a potential source for survival and inoculum build-up of soilborne Phytophthora spp. in ash stands and forest ecosystems in general.

1 aOrlikowski, L B1 aPtaszek, M1 aRodziewicz, A1 aNechwatal, J1 aThinggaard, K1 aJung, T uhttp://dx.doi.org/10.1111/j.1439-0329.2011.00714.x01183nas a2200205 4500008004100000245011100041210006900152300001000221490000700231520048600238653001000724653002000734653001800754653001300772653000900785100002000794700001400814700001400828856013500842 2006 eng d00aFirst record on Phytophthora spp. associated with the decline of European beech stand in south-west Poland0 aFirst record on Phytophthora spp associated with the decline of  a37-460 v423 a

Phytophthora citricola was detected in Siewierz Forest District in soil samples and diseased bark taken from declined 88-111-year-old European beech trees growing in three compartments of Trzebyczka Forest. Phytophthora cambivora was isolated only from diseased fine roots, bleeding cankers near trunk base and aerial canker spots. Both species colonised leaves and young stem parts as well as five-year-old beech branches. Necrosis spread about 1 mm/24 h.

10aBeech10ableeding canker10apathogenicity10aroot rot10asoil1 aOrlikowski, L B1 aOszako, T1 aSzkuta, G uhttps://forestphytophthoras.org/references/first-record-phytophthora-spp-associated-decline-european-beech-stand-south-west-poland