Antimicrobials in Phytophthora isolation media and the growth of Phytophthora species

2020 ◽  
Vol 69 (8) ◽  
pp. 1426-1436 ◽  
Author(s):  
Suchana R. Sarker ◽  
Jen McComb ◽  
Treena I. Burgess ◽  
Giles E. St. J. Hardy
Keyword(s):  
Phytophthora Species ◽  
Isolation Media

scholarly journals Phytophthora mediterranea sp. nov., a New Species Closely Related to Phytophthora cinnamomi from Nursery Plants of Myrtus communis in Italy

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 682
Author(s):  
Carlo Bregant ◽  
Antonio A. Mulas ◽  
Giovanni Rossetto ◽  
Antonio Deidda ◽  
Lucia Maddau ◽  
...  
Keyword(s):  
New Species ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Colony Growth ◽  
Phytophthora Species ◽  
Maximum Temperature ◽  
Pathogenicity Test ◽  
Forest Nurseries ◽  
Collar And Root Rot ◽  
A New Species

Monitoring surveys of Phytophthora related diseases in four forest nurseries in Italy revealed the occurrence of fourteen Phytophthora species to be associated with collar and root rot on fourteen plants typical of Mediterranean and alpine regions. In addition, a multilocus phylogeny analysis based on nuclear ITS and ß-tubulin and mitochondrial cox1 sequences, as well as micromorphological features, supported the description of a new species belonging to the phylogenetic clade 7c, Phytophthora mediterranea sp. nov. Phytophthora mediterranea was shown to be associated with collar and root rot symptoms on myrtle seedlings. Phylogenetically, P. mediterranea is closely related to P. cinnamomi but the two species differ in 87 nucleotides in the three studied DNA regions. Morphologically P. mediterranea can be easily distinguished from P. cinnamomi on the basis of its smaller sporangia, colony growth pattern and higher optimum and maximum temperature values. Data from the pathogenicity test showed that P. mediterranea has the potential to threaten the native Mediterranean maquis vegetation. Finally, the discovery of P. cinnamomi in alpine nurseries, confirms the progressive expansion of this species towards cold environments, probably driven by climate change.

scholarly journals Phytophthora Diversity in Pennsylvania Nurseries and Greenhouses Inferred from Clinical Samples Collected over Four Decades

2020 ◽  
Vol 8 (7) ◽  
pp. 1056
Author(s):  
Cody Molnar ◽  
Ekaterina Nikolaeva ◽  
Seonghwan Kim ◽  
Tracey Olson ◽  
Devin Bily ◽  
...  
Keyword(s):  
Plant Species ◽  
Morphological Characteristics ◽  
Phytophthora Species ◽  
Clinical Samples ◽  
Department Of Agriculture ◽  
Distinct Subgroup ◽  
Exotic Pathogens ◽  
Diverse Plant Species ◽  
Insight Into ◽  
Diverse Plant

The increasing movement of exotic pathogens calls for systematic surveillance so that newly introduced pathogens can be recognized and dealt with early. A resource crucial for recognizing such pathogens is knowledge about the spatial and temporal diversity of endemic pathogens. Here, we report an effort to build this resource for Pennsylvania (PA) by characterizing the identity and distribution of Phytophthora species isolated from diverse plant species in PA nurseries and greenhouses. We identified 1137 Phytophthora isolates cultured from clinical samples of >150 plant species submitted to the PA Department of Agriculture for diagnosis from 1975 to 2019 using sequences of one or more loci and morphological characteristics. The three most commonly received plants were Abies, Rhododendron, and Pseudotsuga. Thirty-six Phytophthora species identified represent all clades, except 3 and 10, and included a distinct subgroup of a known species and a prospective new species. Prominent pathogenic species such as P. cactorum, P. cinnamomi, P. nicotianae, P. drechsleri, P. pini, P. plurivora, and P. sp. kelmania have been found consistently since 1975. One isolate cultured from Juniperus horizontalis roots did not correspond to any known species, and several other isolates also show considerable genetic variation from any authentic species or isolate. Some species were isolated from never-before-documented plants, suggesting that their host range is larger than previously thought. This survey only provides a coarse picture of historical patterns of Phytophthora encounters in PA nurseries and greenhouses because the isolation of Phytophthora was not designed for a systematic survey. However, its extensive temporal and plant coverage offers a unique insight into the association of Phytophthora with diverse plants in nurseries and greenhouses.

The Phytophthora species assemblage and diversity in riparian alder ecosystems of western Oregon, USA

Mycologia ◽  
2015 ◽  
Vol 107 (5) ◽  
pp. 889-902 ◽  
Author(s):  
Laura Lee Sims ◽  
Wendy Sutton ◽  
Paul Reeser ◽  
Everett M Hansen
Keyword(s):  
Phytophthora Species ◽  
Species Assemblage

scholarly journals Sudden Phytophthora Dieback of Wild Cherry Trees in Northwest Hungary

2016 ◽  
Vol 12 (2) ◽  
pp. 117-124
Author(s):  
Judit Sárándi-Kovács ◽  
László Nagy ◽  
Ferenc Lakatos ◽  
György Sipos
Keyword(s):  
Prunus Avium ◽  
Deciduous Forest ◽  
Flood Plain ◽  
Phytophthora Species ◽  
Soil Conditions ◽  
Wild Cherry ◽  
Plain Area ◽  
Phytophthora Spp ◽  
Mixed Deciduous Forest ◽  
Cherry Trees

Abstract During a regular survey of declining forests in 2011, sudden dieback symptoms were observed on scattered wild cherry trees (Prunus avium) in a mixed deciduous forest stand, located in the flood plain area of the Rába River, in northwest Hungary. In this study, we correlated both soil conditions and presence of Phytophthora spp. to dieback of cherry trees. Two Phytophthora species, P. polonica and P. plurivora, were isolated from the rhizosphere soil of the dying trees. By contrast, only P. polonica was recovered from the necrotic tissues of symptomatic roots. Stem and root inoculation tests on cherry seedlings showed pathogenicity of both species, although P. polonica proved to be more virulent. This is the first report of natural infections of P. polonica.

scholarly journals Interaction between Hymenoscyphus fraxineus and Phytophthora species on young Fraxinus excelsior seedlings

2018 ◽  
Vol 94 (02) ◽  
pp. 135-139 ◽  
Author(s):  
Ivan Milenkovi´c ◽  
Nenad Keča ◽  
Dragan Karadži´c ◽  
Justyna A. Nowakowska ◽  
Tomasz Oszako ◽  
...  
Keyword(s):  
Phytophthora Species ◽  
Fraxinus Excelsior ◽  
Hymenoscyphus Fraxineus

New Phytophthora species in clade 2a from the Asia-Pacific region including a re-examination of P. colocasiae and P. meadii

2021 ◽  
Vol 20 (2) ◽  
pp. 111-129
Author(s):  
Quynh N. Dang ◽  
Thu Q. Pham ◽  
Frans Arentz ◽  
Giles E. StJ. Hardy ◽  
Treena I Burgess
Keyword(s):  
Phytophthora Species ◽  
Asia Pacific ◽  
Pacific Region ◽  
Asia Pacific Region

Detection of oomycide-insensitive Phytophthora isolates in Maryland ornamental nurseries and Mid-Atlantic landscapes provide data for reconsidering management strategies

2021 ◽  
Author(s):  
Justine Beaulieu ◽  
Johanna Del Castillo Munera ◽  
Yilmaz Balci
Keyword(s):  
Growth Rate ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Resistance Management ◽  
Phytophthora Species ◽  
Oak Forests ◽  
Relative Growth ◽  
Off Label ◽  
Potting Media ◽  
Almost All

Five Phytophthora species comprising a total of 243 isolates (77 P. cinnamomi, 23 P. citrophthora, 18 P. multivora, 18 P. pini, and 107 P. plurivora) were screened for sensitivity to mefenoxam, fosetyl-Al, dimethomorph, dimethomorph + ametoctradin and fluoxastrobin using amended agar assays. Mefenoxam-insensitive isolates were detected within P. cinnamomi (4%), P. multivora (11%), and P. plurivora (12%) even at approximately 2.5x the recommended label rate. These isolates were also insensitive to higher (off-label) concentrations of fluoxastrobin. Concentrations of dimethomorph (400 g/mL) and dimethomorph + ametoctradin (100 g/mL) were mostly effective in mycelial growth inhibition, but two P. plurivora isolates were insensitive, suggesting that resistance management is required. All mefenoxam-insensitive isolates were sensitive to fosetyl-Al at the label rate. Surprisingly, the populations of P. cinnamomi from mid-Atlantic oak forests included insensitive isolates. With almost all species, isolates recovered from asymptomatic hosts (e.g., soil/potting media collected of randomly selected asymptomatic hosts) had a significantly greater relative growth rate when compared to isolates recovered from symptomatic hosts (e.g., isolates recovered from lesions or wilted plants). These findings suggest that mefenoxam should no longer be used to manage oomycetes in Maryland ornamental nurseries and that the use of fluoxastrobin should be limited.

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