scholarly journals Survey in Nurseries and Irrigation Water Reservoirs as Sources of Oomycetes Found in Avocado Orchards in the Canary Islands

Plant Disease ◽  
2019 ◽  
Vol 103 (6) ◽  
pp. 1264-1274
Author(s):  
Cristina Rodríguez-Padrón ◽  
Ana Rodríguez ◽  
Felipe Siverio
Keyword(s):  
Canary Islands ◽  
Irrigation Water ◽  
Potential Role ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Soil Samples ◽  
Pathogenic Species ◽  
Water Reservoirs ◽  
Substrate Preparation ◽  
Phytophthora Spp

Nursery stocks and irrigation water are important sources of Phytophthora spp. In this study, 20 irrigation water reservoirs and 10 avocado nurseries were surveyed in the Canary Islands between 2013 and 2015 to investigate their potential role in disseminating pathogenic species in avocado orchards. Phytophthora multivora was isolated from one of the irrigation reservoirs, whereas, in two surveys conducted in nurseries, Phytophthora cinnamomi, the primary pathogen in avocado, was detected in addition to other Phytophthora species (P. lacustris, P. multivora, P. nicotianae, P. niederhauserii, and P. palmivora) and Phytopythium vexans. The species recovered from nurseries were isolated mostly from propagated plants but also from nursery irrigation water, soil used for substrate preparation, and soil samples collected in orchards that supply seeds for seedling propagation. Species recovered from nurseries correlated with those found in avocado orchards in a previous study, except for P. lacustris, suggesting that nurseries could be involved in their dissemination in avocado orchards. The improved sanitary status of nurseries resulted in reduced incidence in the second survey, indicating the importance of nursery monitoring to reduce infestations.

scholarly journals Illustration of Key Morphological Characteristics of Phytophthora Species Identified in Virginia Nursery Irrigation Water

2006 ◽  
Vol 7 (1) ◽  
pp. 41 ◽  
Author(s):  
Elizabeth A. Bush ◽  
Erik L. Stromberg ◽  
Chuanxue Hong ◽  
Patricia A. Richardson ◽  
Ping Kong
Keyword(s):  
Irrigation Water ◽  
Ornamental Plants ◽  
Morphological Characteristics ◽  
Phytophthora Species ◽  
Molecular Methods ◽  
Morphological Identification ◽  
Taxonomic Identification ◽  
Effluent Water ◽  
Phytophthora Spp ◽  
Diagnostic Characteristics

Phytophthora diseases are commonly diagnosed on ornamental plants, but taxonomic identification to species can be intimidating. This illustrative guide is designed to aid diagnosticians in morphological identification of certain Phytophthora spp. that have been reported in irrigation and effluent water in nurseries. Using both morphological and molecular methods, the authors identify diagnostic characteristics that are consistent and easy to use. Accepted for publication 6 April 2006. Published 21 June 2006.

scholarly journals Effects of Fuel Reduction Treatments on Incidence of Phytophthora Species in Soil of a Southern Appalachian Mountain Forest

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 811-820 ◽  
Author(s):  
I. M. Meadows ◽  
D. C. Zwart ◽  
S. N. Jeffers ◽  
T. A. Waldrop ◽  
W. C. Bridges
Keyword(s):  
Prescribed Burning ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Mountain Forest ◽  
Fuel Reduction ◽  
Appalachian Mountain ◽  
Phytophthora Spp ◽  
Southern Appalachian ◽  
Southern Appalachian Mountain ◽  
Mountain Laurel

The National Fire and Fire Surrogate Study was initiated to study the effects of fuel reduction treatments on forest ecosystems. Four fuel reduction treatments were applied to three sites in a southern Appalachian Mountain forest in western North Carolina: prescribed burning, mechanical fuel reduction, mechanical fuel reduction followed by prescribed burning, and a nontreated control. To determine the effects of fuel reduction treatments on Phytophthora spp. in soil, incidences were assessed once before and twice after fuel reduction treatments were applied. Also, the efficiency of the baiting bioassay used to detect species of Phytophthora was evaluated, and the potential virulence of isolates of Phytophthora spp. collected from forest soils was determined. Phytophthora cinnamomi and P. heveae were the only two species recovered from the study site. Incidences of these species were not significantly affected by fuel reduction treatments, but incidence of P. cinnamomi increased over time. In the baiting bioassay, camellia leaf disks were better than hemlock needles as baits. P. cinnamomi was detected best in fresh soil, whereas P. heveae was detected best when soil was air-dried and remoistened prior to baiting. Isolates of P. heveae were weakly virulent and, therefore, potentially pathogenic—causing lesions only on wounded mountain laurel and rhododendron leaves; however, isolates of P. cinnamomi were virulent and caused root rot and mortality on mountain laurel and white pine plants.

PHYTOPHTHORA SPP. IN SOILS OF THE OKANAGAN AND SIMILKAMEEN VALLEYS OF BRITISH COLUMBIA

1964 ◽  
Vol 42 (10) ◽  
pp. 1411-1415 ◽  
Author(s):  
D. L. McIntosh
Keyword(s):  
British Columbia ◽  
Irrigation Water ◽  
Soil Samples ◽  
Phytophthora Cactorum ◽  
Phytophthora Spp ◽  
Orchard Soils ◽  
Chemotactic Effect ◽  
Irrigated Soils ◽  
Cultivated Soils

Phytophthora cactorum is widely distributed in irrigated soils in the Okanagan and Similkameen valleys of British Columbia. Other species isolated, when over 1800 soil samples were assayed for the presence of Phytophthora fungi, were P. cryptogea twice, P. cambivora once, P. megasperma var. sojae once, and P. drechsleri twice. Phytophthora spp. were not recovered from virgin soils nor from non-irrigated cultivated soils, nor from orchard soils receiving irrigation water that is chlorinated. P. cactorum, P. cryptogea, and P. cambivora are pathogenic to rootlets of pear, cherry, apricot, and peach seedlings. P. megasperma var. sojae and P. drechsleri were weakly to non-pathogenic to these hosts. Pear and apple rootlets exerted a chemotactic effect on zoospores of P. cambivora and P. cactorum.

scholarly journals First Report of Phytophthora cinnamomi on Quercus laurifolia

Plant Disease ◽  
2002 ◽  
Vol 86 (4) ◽  
pp. 441-441 ◽  
Author(s):  
A. K. Wood ◽  
F. H. Tainter
Keyword(s):  
Phytophthora Cinnamomi ◽  
Soil Extract ◽  
Selective Medium ◽  
Phytophthora Species ◽  
Soil Samples ◽  
Tissue Samples ◽  
First Report ◽  
Central Florida ◽  
Oak Trees ◽  
Length Width

In May 2001, bleeding cankers were observed on several laurel oak (Quercus laurifolia) trees in central Florida. Affected trees had chlorotic leaves, sparse canopies, and little new growth. Multiple cankers were present on the trunk and extended from the soil line up to approximately 5 m. Each canker had a reddish to dark brown or black exudate. From two of the infected trees, tissue samples were taken from beneath the bark around the edge of an actively growing lesion and transferred directly to Phytophthora-selective medium (1), and three soil cores (2 cm in diameter, 20 cm deep) were collected from the base of each tree. A baiting bioassay (with camellia leaf disks and shore juniper and eastern hemlock needles as baits) was used to assay fresh composite soil samples for Phytophthora species (1). P. cinnamomi was recovered from both tissue and soil samples (2). Mycelia were coralloid with abundant hyphal swellings. Sporangia were produced in 1.5% nonsterilized soil extract solution. Sporangia were ovoid to ellipsoid in shape and nonpapillate. Average sporangium size was 72 × 45 μm (length × width). To our knowledge, this is the first report of P. cinnamomi on laurel oak trees. References: (1) A. J. Ferguson and S. N. Jeffers. Plant Dis. 83:1129, 1999. (2) G. M. Waterhouse. Key to the species of Phytophthora de Bary. Mycol. Pap. 92. CMI. Kew, UK, 1963.

scholarly journals The Use of qPCR Reveals a High Frequency of Phytophthora quercina in Two Spanish Holm Oak Areas

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 697 ◽  
Author(s):  
Beatriz Mora-Sala ◽  
Mónica Berbegal ◽  
Paloma Abad-Campos
Keyword(s):  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Holm Oak ◽  
Oak Decline ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Molecular Approaches ◽  
Isolation Techniques ◽  
Phytophthora Spp ◽  
Long Time

The struggling Spanish holm oak woodland situation associated with Phytophthora root rot has been studied for a long time. Phytophthora cinnamomi is considered the main, but not the only species responsible for the decline scenario. This study verifies the presence and/or detection of Phytophthora species in two holm oak areas of Spain (southwestern “dehesas” and northeastern woodland) using different isolation and detection approaches. Direct isolation and baiting methods in declining and non-declining holm oak trees revealed Phytophthora cambivora, Phytophthora cinnamomi, Phytophthora gonapodyides, Phytophthora megasperma, and Phytophthora pseudocryptogea in the dehesas, while in the northeastern woodland, no Phytophthora spp. were recovered. Statistical analyses indicated that there was not a significant relationship between the Phytophthora spp. isolation frequency and the disease expression of the holm oak stands in the dehesas. Phytophthora quercina and P. cinnamomi TaqMan real-time PCR probes showed that both P. cinnamomi and P. quercina are involved in the holm oak decline in Spain, but P. quercina was detected in a higher frequency than P. cinnamomi in both studied areas. Thus, this study demonstrates that molecular approaches complement direct isolation techniques in natural and seminatural ecosystem surveys to determine the presence and distribution of Phytophthora spp. This is the first report of P. pseudocryptogea in Europe and its role in the holm oak decline should be further studied.

scholarly journals Phytophthora spp. Associated with Forest Soils in Eastern and North-Central U.S. Oak Ecosystems

Plant Disease ◽  
2007 ◽  
Vol 91 (6) ◽  
pp. 705-710 ◽  
Author(s):  
Y. Balci ◽  
S. Balci ◽  
J. Eggers ◽  
W. L. MacDonald ◽  
J. Juzwik ◽  
...  
Keyword(s):  
Phytophthora Cinnamomi ◽  
Soil Samples ◽  
Crown Condition ◽  
North Central ◽  
Latitude Range ◽  
Isolation Frequency ◽  
Phytophthora Spp ◽  
Oak Trees ◽  
Site Characteristics ◽  
Isolated Species

A survey of soils associated with oak species was conducted in 2003 and 2004 in Indiana, Illinois, Maryland, Michigan, Minnesota, Pennsylvania, Ohio, West Virginia, and Wisconsin to investigate the occurrence of Phytophthora spp. Soils taken from around the base of healthy and declining oak trees were flooded with H2O and Quercus robur leaflets were used as bait for Phytophthora spp. From 829 soil samples collected near trees, 21% were positive for Phytophthora spp., with 55% of the 125 sites surveyed yielding a Phytophthora sp. Phytophthora cinnamomi was the most frequently isolated species, representing 69.4% of the Phytophthora-infested sites surveyed. Other species, in decreasing order of isolation frequency were Phytophthora sp. 2, P. citricola, P. europaea, P. cambivora, P. quercina-like isolates, and Phytophthora sp. 1. No significant association was found between the presence of Phytophthora organisms and site characteristics such as latitude, elevation, soil pH, or the crown condition of the trees. However, in P. cinnamomi-infested sites, a significant association was found with the deteriorating crown status of Q. alba and the presence of P. cinnamomi. The absence of P. cinnamomi above the 40°N latitude range also was noteworthy.

Residues and Persistence of Glyphosate in Irrigation Water

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 47-50 ◽  
Author(s):  
R. D. Comes ◽  
V. F. Bruns ◽  
A. D. Kelley
Keyword(s):  
Irrigation Water ◽  
Soil Samples ◽  
Single Site ◽  
Application Site ◽  
Canal Water ◽  
Aminomethylphosphonic Acid ◽  
Dry Soil

Neither glyphosate [N-(phosphonomethyl)glycine] nor the soil metabolite aminomethylphosphonic acid were detected in the first flow of water through two canals following application of glyphosate at 5.6 kg/ha to ditchbanks when the canals were dry. Soil samples collected the day before canals were filled (about 23 weeks after treatment) contained about 0.35 ppm glyphosate and 0.78 ppm aminomethylphosphonic acid in the 0 to 10-cm layer. When glyphosate was metered into the water at a rate calculated to provide 150 ppb in the canal water at a single site on two flowing canals, about 70% of the glyphosate was accounted for 1.6 km downstream from the application site. Thereafter, the rate of disappearance diminished, and about 58% of the applied glyphosate was present at the end of the canals 8 or 14.4 km downstream from the introduction sites.

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 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.

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