@article {1294133220040401, title = {Phytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies.}, journal = {Plant Pathology}, volume = {53}, number = {2}, year = {2004}, pages = {197 - 208}, abstract = {

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{\textperiodcentered}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 {\textquoteleft}alder Phytophthora{\textquoteright} 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 {\textquoteleft}alder Phytophthora{\textquoteright} infects alders downstream. Baiting tests showed that the {\textquoteleft}alder Phytophthora{\textquoteright} 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 {\textquoteleft}alder Phytophthora{\textquoteright} in soil.

}, keywords = {ALDER {\textendash} Diseases \& pests, Alnus, Bavaria, diseases, fungal diseases of plants, GERMANY, nursery, pathway, Phytophthora, plantation, riparian areas}, issn = {00320862}, doi = {10.1111/j.0032-0862.2004.00957.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.0032-0862.2004.00957.x/abstract}, author = {T. Jung and Blaschke, M.} } @article {3976, title = {Phytophthora quercina sp. nov., causing root rot of European oaks}, journal = {Mycological Research}, volume = {103}, year = {1999}, month = {7/1999}, pages = {785 - 798}, abstract = {

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{\textquoteright}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.

}, issn = {09537562}, doi = {10.1017/S0953756298007734}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208606115}, author = {T. Jung and Cooke, D. E. L. and Blaschke, H. and Duncan, J. M. and W. O{\ss}wald} }