<i>Phytophthora</i> species in forest streams in Oregon and Alaska

Reeser, Paul; Sutton, Wendy; Hansen, E. M.; Remigi, Philippe; Adams, G.C.

doi:10.3852/10-013

Cited by 114 publications

(126 citation statements)

References 27 publications

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“…Phylogenetic analyses revealed these to be mostly in Clade 6, but some Clade 2 species also were encountered. Phytophthora species in Clade 6 often are abundant in rivers and riparian ecosystems (Reeser et al 2011, Hü berli et al 2013. This is consistent with the view that Clade 6 species are adapted as saprotrophs on fallen leaves and other plant debris in rivers (Brasier et al 2003.…”

Section: Figmentioning

confidence: 99%

“…These species are found in Europe, North America and Australia (Brasier et al 2003, Reeser et al 2011, Stukely 2012. Both appear to be strongly associated with aquatic habitats where they are thought to exist as saprotrophs on plant debris (Brasier et al 2003, Nechwatal andMendgen 2006).…”

Section: Figmentioning

confidence: 99%

“…In a similar study conducted in Oregon and Alaska, 18 Phytophthora spp. were recovered from streams of which P. gonapodyides and P. chlamydospora were the most frequently encountered (Reeser et al 2011). Nine Phytophthora spp.…”

Section: Introductionmentioning

confidence: 99%

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MultiplePhytophthoraspecies associated with a single riparian ecosystem in South Africa

Nagel¹,

Slippers²,

Wingfield

et al. 2015

Mycologia

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The diversity of Phytophthora spp. in rivers and riparian ecosystems has received considerable international attention, although little such research has been conducted in South Africa. This study determined the diversity of Phytophthora spp. within a single river in Gauteng province of South Africa. Samples were collected over 1 y including biweekly river baiting with Rhododendron indicum leaves. Phytophthora isolates were identified with phylogenetic analyses of sequences for the internal transcribed spacer (ITS) region of the ribosomal DNA and the mitochondrial cytochrome oxidase c subunit I (coxI) gene. Eight Phytophthora spp. were identified, including a new taxon, P. taxon Sisulu-river, and two hybrid species from Cooke's ITS clade 6. Of these, species from Clade 6 were the most abundant, including P. chlamydospora and P. lacustris. Species residing in Clade 2 also were encountered, including P. multivora, P. plurivora and P. citrophthora. The detection of eight species in this investigation of Phytophthora diversity in a single riparian river ecosystem in northern South Africa adds to the known diversity of this genus in South Africa and globally.

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Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

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MultiplePhytophthoraspecies associated with a single riparian ecosystem in South Africa

Nagel¹,

Slippers²,

Wingfield

et al. 2015

Mycologia

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“…For such testing to be cost-effective, planning and knowledge about the development of oomycete populations in time is vital. The majority of quantitative studies of oomycete populations in water use either baiting methods [5] or, more recently, quantitative PCR, with only a very few directly plating and quantifying viable colony forming units (CFU) [6][7][8]. Simple methods that can estimate CFU development as a function of environmental variables will enhance testing capabilities.…”

Section: Digital Signaturementioning

confidence: 99%

A simple model describes development of early peaks in oomycete zoospore inoculum detected in southern UK outdoors horticultural reservoirs

Pettitt

Skjøth

2016

Acta Agrobot

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The numbers of water-borne oomycete propagules in outdoor reservoirs used in horticultural nurseries within the UK are investigated in this study. Water samples were recovered from 11 different horticultural nurseries in the southern UK during Jan-May in 2 "cool" years (2010 and 2013; winter temperatures 2.0 and 0.4°C below UK Met Office 30 year winter average, respectively) and 2 "warm" years (2008 and 2012; winter temperatures 1.2 and 0.9°C above UK Met Office 30 year winter average, respectively). Samples were analyzed for total number of oomycete colony forming units (CFU), predominantly members of the families Saprolegniaceae and Pythiaceae, and these were combined to give monthly mean counts. The numbers of CFU were investigated with respect to prevailing climate in the region: mean monthly air temperatures calculated by using daily observations from the nearest climatological station. The investigations show that the number of CFU during spring can be explained by a linear first-order equation and a statistically significant r 2 value of 0.66 with the simple relationship:where a is the rate of inoculum development with temperature T, and b is the baseload population at temperatures below T b . Despite the majority of oomycete CFU detected being non-phytopathogenic members of the Saprolegniaceae, total oomycete CFU counts are still of considerable value as indicators of irrigation water treatment efficacy and cleanliness of storage tanks. The presence/absence of Pythium spp. was also determined for all samples tested, and Pythium CFU were found to be present in the majority, the exceptions all being particularly cold months (January and February 2010, and January 2008). A simple scenario study (+2 deg C) suggests that abundance of water-borne oomycetes during spring could be affected by increased temperatures due to climate change.

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“…Many Phytophthora species other than P. ramorum are relatively abundant in natural streams in healthy forests, even if the species present are poorly characterised, and their ecology is still largely unknown (Reeser et al, 2011). As a by-product, monitoring for the presence of P. ramorum is therefore helping increase our general knowledge of naturally-occurring Phytophthora species (Hansen, 2008).…”

Section: Additional Information Options To Reduce Likelihood Of Intromentioning

confidence: 99%

Scientific Opinion on the Pest Risk Analysis onPhytophthora ramorumprepared by the FP6 project RAPRA

Rossi¹

2011

EFSA Journal

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The Panel on Plant Health was asked to deliver a scientific opinion on the Pest Risk Analysis on Phytophthora ramorum prepared by the FP6 project RAPRA, taking into account comments by Member States and additional information since RAPRA. P. ramorum is the oomycete causing sudden oak death in the USA and leaf and twig blight/dieback on a range of ornamental species in North America and Europe. Currently P. ramorum is not listed as a harmful organism in Council Directive 2000/29/EC, but the Commission adopted in 2002 provisional emergency measures to prevent introduction into and spread within the EU. Recent large-scale outbreaks in Japanese larch (Larix kaempferi) plantations in the UK and Ireland have worsened the potential consequences in the risk assessment area. However, the Panel concludes that the broad narrative in the RAPRA report stands and supports its conclusion that "There is a risk of further entry (of known or new lineages and/or mating types), establishment and […] impact". It is advisable to avoid introductions of different lineages because of inherent phenotypic differences and the potential for sexual recombination. The Panel supports the management options proposed in the RAPRA report and adds further measures for consideration. Uncertainty remains over the extent to which the association between control measures and gradual reduction in the number of cases in nurseries is causal. The emergency measures have not prevented outbreaks occurring in the natural environment. The many other remaining uncertainties (fitness of progeny, hybridisation with other Phytophthora species, host range and epidemiological role of new hosts, early detection of new outbreaks, understanding of long-range dispersal, structure of plant trade networks, origin of the pathogen) call for further research on P. ramorum across Europe. 4 Editorial changes have been made on pages 51 (acronym PRA removed as it was not in line with the Panel's dictionary as discussed in Appendix 2 of the Guidance on a harmonised framework for pest risk assessment and the identification and evaluation of pest risk management options by EFSA) and 89 (statement which referred to the Panel agreeing with the RAPRA conclusion that "P. ramorum fulfils the criteria of a quarantine pest" was removed as requested by the Panel during adoption of the draft opinion). The changes do not affect the overall conclusions of the opinion. To avoid confusion the original version has been removed from the website. The scope of this Scientific Opinion is the evaluation of the RAPRA report, taking into consideration the comments of Member States as well as additional information published after finalisation of the RAPRA report, or not cited in the RAPRA report. A systematic literature search until March 2011 was carried out. It should be noted that the scientific community is concerned by the shift of P. ramorum to new hosts (with a special focus on the Japanese larch) and its further spread, and therefore new results of ongoing research are constantly be...

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Phytophthora species in forest streams in Oregon and Alaska

Cited by 114 publications

References 27 publications

MultiplePhytophthoraspecies associated with a single riparian ecosystem in South Africa

MultiplePhytophthoraspecies associated with a single riparian ecosystem in South Africa

A simple model describes development of early peaks in oomycete zoospore inoculum detected in southern UK outdoors horticultural reservoirs

Scientific Opinion on the Pest Risk Analysis onPhytophthora ramorumprepared by the FP6 project RAPRA

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