02540nas a2200277 4500008004100000022001300041245012500054210006900179300001400248490000700262520170100269653003101970653001002001653001202011653001302023653003002036653001202066653001202078653001202090653001702102653001502119653001902134100001202153700001602165856008102181 2004 eng d a0032086200aPhytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies.0 aPhytophthora root and collar rot of alders in Bavaria distributi a197 - 2080 v533 a

A survey of symptoms of phytophthora root and collar rot of common (Alnus glutinosa) and grey alder (A. incana) in riparian and forest stands in Bavaria was conducted by the Bavarian State Forestry and river authorities. Symptoms were seen in 1041 out of 3247 forest alder stands. The majority of the affected stands (80·9%) were less than 21 years old; 46% of these young stands were growing on nonflooded sites and 92% had been planted. The riparian survey showed that symptoms were widespread along more than 50% of the river systems. Along some rivers the disease incidence exceeded 50%. The ‘alder Phytophthora’ was recovered from 166 of 185 riparian and forest alder stands with symptoms. In 58 of the 60 rivers and streams investigated in detail, the source of inoculum was traced back to infested young alder plantations growing on the river banks or on forest sites that drain into the rivers. Once introduced to a river system, the ‘alder Phytophthora’ infects alders downstream. Baiting tests showed that the ‘alder Phytophthora’ was present in rootstocks of alders from three out of four nurseries which regularly bought in alder plants for re-sale, but not in rootstocks from four nurseries that grew their own alders from seed. In addition, the infected nurseries used water from infested water courses for irrigation. The Bavarian State Ministry for Agriculture and Forestry has developed a code of practice for producing healthy alder plants in forest nurseries. This includes a 3-year fallow period between bare-rooted alder crops because of poor survival of the ‘alder Phytophthora’ in soil.

10aALDER – Diseases & pests10aAlnus10aBavaria10adiseases10afungal diseases of plants10aGERMANY10anursery10apathway10aPhytophthora10aplantation10ariparian areas1 aJung, T1 aBlaschke, M uhttp://onlinelibrary.wiley.com/doi/10.1111/j.0032-0862.2004.00957.x/abstract02554nas a2200193 4500008004100000022001300041245007000054210006700124260001100191300001400202490000800216520198900224100001202213700001702225700001602242700001602258700001502274856007102289 1999 eng d a0953756200aPhytophthora quercina sp. nov., causing root rot of European oaks0 aPhytophthora quercina sp nov causing root rot of European oaks c7/1999 a785 - 7980 v1033 a

In a 3 year study of oak (Quercus robur, Q. petraea, Q. cerris, Q. pubescens and Q. ilex) decline in Central and Southern Europe, a papillate homothallic Phytophthora species was isolated consistently, with other Phytophthora spp., from necrotic fine roots by direct plating on to selective agar medium and from rhizosphere soil samples by baiting with leaves of Quercus robur. The morphology, physiology, RAPD banding patterns and pathogenicity against apple fruits of this Phytophthora sp. are described and compared with those of other papillate Phytophthora species from Waterhouse's Group I, namely P. cactorum, P. clandestina, P. idaei, P. iranica, P. pseudotsugae and P. tentaculata, and papillate Group III P. citricola. The papillate Phytophthora isolates from oak differed from all other Group I species by their uniform, dome-shaped and cottonwool-like colony growth pattern on V8 juice agar and malt extract agar, the frequent occurrence of sympodially branched primary hyphae, a high proportion of elongated, ellipsoid or ovoid oogonia, the absence of amphigynous antheridia and RAPD banding patterns. Additionally, there was no other species in Group I with as much variation in size and shape of the sporangia or large proportion of sporangia with a curved apex, hyphal projections, lateral displacement of the papilla and lateral attachment to the sporangiophore. In pathogenicity tests with infested soil, the isolates proved to be more pathogenic to Q. robur than any other Phytophthora sp. recovered from declining oaks in Central Europe. Based on their unique combination of cultural, sporangial and gametangial morphology, pathogenicity and close association with Quercus but not other trees, the papillate Phytophthora isolates from oak are described as Phytophthora quercina sp. nov.

1 aJung, T1 aCooke, D E L1 aBlaschke, H1 aDuncan, J M1 aOßwald, W uhttp://www.sciencedirect.com/science/article/pii/S0953756208606115