02292nas a2200157 4500008004100000245012400041210006900165300001200234490000700246520174600253100001601999700001902015700001602034700001902050856006502069 2009 eng d00aIdentification and frequency of Phytophthora species associated with foliar diseases in California ornamental nurseries0 aIdentification and frequency of Phytophthora species associated  a883-8900 v933 a

Numerous ornamental nurseries in 32 California counties were surveyed for leaf spots as part of the California Department of Food and Agriculture mandated surveys targeting Phytophthora ramorum. Tissue collected during the 2005 and 2006 surveys was initially screened by a Phytophthora-specific enzyme-linked immunosorbent assay. All positives samples were further tested using polymerase chain reaction to determine if P. ramorum was present. P. ramorum was detected in 1% of the total number of samples taken during the surveys. A total of 377 isolates were identified as species of Phytophthora other than P. ramorum, and their identity was determined by internal transcriber spacer (ITS) sequences. Subsets of the putative ITS-species were further verified using accepted morphological characters. Thirteen species of Phytophthora were found: P. cactorum, P. cambivora, P. citricola, P. citrophthora, P. cryptogea, P. foliorum, P. gonapodyides, P. hibernalis, P. nemorosa, P. ‘Pgchlamydo’, P. pseudosyringae, P. syringae, and P. tropicalis. P. syringae and P. citricola made up 55% of the total number of isolates. Species thought to be strictly forest pathogens, P. nemorosa and P. pseudosyringae, each made up less than 4% of the isolates. To test pathogenicity of acquired isolates, subsets of different species of Phytophthora were inoculated onto leaves of selected host plant genera. Of the 66 pathogen–host genera combinations tested, 44 resulted in lesion formation. Disease symptoms appeared as dark, water-soaked lesions with irregular margins and were similar among Phytophthora species.

1 aYakabe, L E1 aBlomquist, C L1 aThomas, S L1 aMacDonald, J D uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-9-088302361nas a2200181 4500008004100000022001400041245012400055210006900179260001600248300001400264490000700278520175500285100001602040700002202056700001602078700001902094856006602113 2009 eng d a0191-291700aIdentification and Frequency of Phytophthora Species Associated with Foliar Diseases in California Ornamental Nurseries0 aIdentification and Frequency of Phytophthora Species Associated  cJan-09-2009 a883 - 8900 v933 a

Numerous ornamental nurseries in 32 California counties were surveyed for leaf spots as part of the California Department of Food and Agriculture mandated surveys targeting Phytophthora ramorum. Tissue collected during the 2005 and 2006 surveys was initially screened by a Phytophthora-specific enzyme-linked immunosorbent assay. All positives samples were further tested using polymerase chain reaction to determine if P. ramorum was present. P. ramorum was detected in 1% of the total number of samples taken during the surveys. A total of 377 isolates were identified as species of Phytophthora other than P. ramorum, and their identity was determined by internal transcriber spacer (ITS) sequences. Subsets of the putative ITS-species were further verified using accepted morphological characters. Thirteen species of Phytophthora were found: P. cactorum, P. cambivora, P. citricola, P. citrophthora, P. cryptogea, P. foliorum, P. gonapodyides, P. hibernalis, P. nemorosa, P. ‘Pgchlamydo’, P. pseudosyringae, P. syringae, and P. tropicalis. P. syringae and P. citricola made up 55% of the total number of isolates. Species thought to be strictly forest pathogens, P. nemorosa and P. pseudosyringae, each made up less than 4% of the isolates. To test pathogenicity of acquired isolates, subsets of different species of Phytophthora were inoculated onto leaves of selected host plant genera. Of the 66 pathogen–host genera combinations tested, 44 resulted in lesion formation. Disease symptoms appeared as dark, water-soaked lesions with irregular margins and were similar among Phytophthora species.

1 aYakabe, L E1 aBlomquist, C., L.1 aThomas, S L1 aMacDonald, J D uhttps://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-9-088302403nas a2200193 4500008004100000245016200041210006900203260001700272300001600289490000700305520175200312100001202064700001702076700001302093700001402106700001502120700001502135856005902150 2009 eng d00aDifferential behaviour in pathogenicity and enzymatic activities of Phytophthora katsurae strains from coconut trees in Côte d’Ivoire. [Article in French]0 aDifferential behaviour in pathogenicity and enzymatic activities bFACT Limited a1246–12570 v213 a

An experiment was conducted to study epidemiological variation of Phytophthora katsurae on coconut trees from four farming areas. Isolates of the pathogenic agent were first characterized based on morphology of sporocysts, oospore, chlamydospore and mycelium, and this enabled detection of differences between the aggressiveness of strains. Differences were also detected when measuring the mycelium growth of each strain in vitro on different culture media (V8, Malt and Carotte). A second study was conducted to confirm the observed differences based on inoculation (gentle or rough) of coconut plants cv. Equatoriale Guinea Green Dwarf (NVE), which is susceptible to P. katsurae, with each of four strains. Last, the enzymatic dosages of pectate lyase and laccase in pathogen were analysed. These enzymes degrade the pectin and lignin of the plant cell walls. Gentle inoculation enabled assessment of the level of aggressiveness of each strain. The activity of pectate lyase and laccase varied between the strains and the synthesis of these enzymes was correlated to pathogen aggressiveness on the plant. The results showed that the strains of Marc Delorme and Assinie are less aggressive than the strain of Fresco, which is less aggressive than the strain of Robert Michaux. The zoospores and the mycelia are considered as the primary inoculum of the four strains. The β-sitosterol added to V8 medium had no influence on the mycelium growth of the four strains. However, its use as ingredient added to the media favoured an increased production of sporocysts. The discovery of this intra specific variability should be of considerable help in elaborating control methods against P. katsurae of coconut trees.

1 aYao, NR1 aN’Goran, B1 aAllou, K1 aDogbo, DO1 aKonan, KJL1 aKouassi, P uhttp://www.m.elewa.org/JABS/2009/21/Abstract4-Yao.html