Phytophthora nicotianae Can Cause Both Crown Rot and Foliage Blight on Phlox paniculata in South Carolina

2014 ◽  
Vol 15 (4) ◽  
pp. 159-165
Author(s):  
Daniel T. Drechsler ◽  
Steven N. Jeffers ◽  
William C. Bridges
Keyword(s):  
South Carolina ◽  
Aqueous Suspension ◽  
Phytophthora Nicotianae ◽  
Crown Rot ◽  
Experimental Conditions ◽  
Aerial Parts ◽  
Phytophthora Spp ◽  
Potting Medium ◽  
Phlox Paniculata ◽  
Foliage Blight

Phytophthora nicotianae is a common pathogen of many herbaceous perennial plants, and this pathogen has been found causing disease on garden phlox (Phlox paniculata) in wholesale nurseries in South Carolina for a number of years. However, the relationship between P. nicotianae and garden phlox has not been studied or reported previously. Using Koch's postulates and standard inoculation methods for Phytophthora spp., P. nicotianae was found to cause crown rot on P. paniculata when potting medium was infested with colonized vermiculite and to cause foliage blight when aerial parts of the plant were inoculated with an aqueous suspension of zoospores. Foliage blight was more similar to symptoms we observed on garden phlox plants in wholesale nurseries, but crown rot also has been observed previously on plants in these nurseries. The cause of these two diseases was confirmed, but reproduction of Phytophthora foliage blight under experimental conditions was inconsistent. Thus, other factors not yet identified may play a role in the development of Phytophthora foliage blight on garden phlox in nurseries in South Carolina. Accepted for publication 1 September 2014. Published 1 November 2014.

scholarly journals Pumpkin Fruit Rot in North Carolina Caused by Phytophthora nicotianae

Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 923-923
Author(s):  
G. J. Holmes
Keyword(s):  
Fungal Growth ◽  
Average Diameter ◽  
Soft Rot ◽  
Selective Medium ◽  
Phytophthora Nicotianae ◽  
Crown Rot ◽  
Fruit Rot ◽  
Unknown Etiology ◽  
Postharvest Diseases ◽  
Phytophthora Spp

In 1999, during an evaluation of pumpkin (Cucurbita pepo) fruit for susceptibility to naturally occurring postharvest diseases, a soft rot of unknown etiology was noted. No fungal growth or sporulation was seen on the fruit surface and no root or crown rot was observed in the field. When fruit were cross-sectioned, masses of white, floccose mycelium covering large sections of the seed cavity were observed. Rot was observed in 21 fruit (6.4% of the total). The fungus was isolated from symptomatic fruit on a modified P10ARPH agar medium, semi-selective for Phytophthora spp. (2). Isolates from eight fruit formed papillate, ovoid sporangia, abundant chlamydospores, and colonies characteristic of P. nicotianae (1). No oospores were produced. Four sound pumpkin fruit (cv. Early Autumn) were inoculated with four isolates (one isolate per fruit). Each isolate was recovered from a different fruit. Pumpkins were surface sterilized at the point of inoculation by wetting with 70% ethanol. Inoculation was done by removing a small amount of mycelium from pure culture using a sterile, wooden toothpick and inserting it 2 cm deep into opposite sides of the mid section of sound fruit (two inoculations per fruit). Control fruit were punctured with sterile toothpicks (once per fruit). First symptoms appeared 4 days after inoculation at room temperature (22 to 24°C). Symptoms consisted of circular, water-soaked areas originating from the point of inoculation. Average diameter (based on four measurements on two fruit) of the water-soaked lesions were 3 cm at first appearance (i.e., 4 days) and 11 cm 10 days after inoculation. No symptoms developed on controls. When symptomatic fruit were cross-sectioned, masses of white, floccose mycelium were noted. Reisolation of this mycelium onto selective medium yielded P. nicotianae, thus fulfilling Koch's postulates. This is the first report of P. nicotianae causing fruit rot of pumpkins. References: (1) D. C. Erwin and O. K. Ribeiro. 1996. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN. (2) H. D. Shew. Phytopathology 77:1090, 1987.

scholarly journals Four Phytophthora Species Causing Foot and Root Rot of Apricot in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 844-844 ◽  
Author(s):  
A. Pane ◽  
S. O. Cacciola ◽  
S. Scibetta ◽  
G. Bentivenga ◽  
G. Magnano di San Lio
Keyword(s):  
Root Rot ◽  
Sandy Loam ◽  
Phytophthora Nicotianae ◽  
Crown Rot ◽  
Optimum Growth ◽  
Phytophthora Spp ◽  
Leaf Chlorosis ◽  
Breadth Ratio ◽  
Root And Crown Rot ◽  
Fourth Species

In the summer of 2006, 1-year-old apricot (Prunus armeniaca L.) trees with leaf chlorosis, wilting, and defoliation associated with root and crown rot were observed in a nursery in Sicily (Italy). Of 3,000 plants, ~2% was affected. Four Phytophthora spp. (45, 25, 20, and 10% of the isolations of the first, second, third, and fourth species, respectively) were isolated from decayed roots and trunk bark on BNPRAH (3). Axenic cultures were obtained by single-hypha transfers. Isolates of the first species formed petaloid colonies on potato dextrose agar (PDA) and had an optimum growth temperature of 25°C. On V8 agar (VA), they produced persistent, papillate (often bipapillate), ovoid to limoniform sporangia (length/breadth ratio 1.4:1). They did not produce gametangia when paired with A1 and A2 isolates of Phytophthora nicotianae. The second species formed arachnoid colonies, had an optimum growth of 30°C, and produced uni- and bipapillate, ellipsoid, ovoid or pyriform sporangia (length/breadth ratio 1.3:1). All isolates were A2. The third species formed rosaceous colonies on PDA, had an optimum temperature of 28 to 30°C, and produced papillate (sometime bipapillate), ellipsoid or limoniform (length/breadth ratio 2:1), caducous sporangia with a tapered base and a long pedicel (as much as 150 μm). All isolates were A1 type. The fourth species formed petaloid-like colonies on PDA and had an optimum growth of 26 to 28°C. On VA, it produced papillate (sometimes bipapillate), ovoid (length/breadth ratio 1.3:1), and decidous sporangia with a short pedicel (<4 μm). The isolates were homothallic and produced oogonia (25 to 31 μm in diameter) with paragynous antheridia and aplerotic oospores. On the basis of morphological and cultural characters, the species were identified as P. citrophthora, P. nicotianae, P. tropicalis and P. cactorum. Identification was confirmed by the electrophoretic analysis of total mycelial proteins and four isozymes (acid and alkaline phosphatases, esterase, and malate dehydrogenase) on polyacrylamide gel (1). Analysis of internal transcribed spacer (ITS) regions of rDNA using the ITS 4 and ITS 6 primers for DNA amplification (2) revealed 99 to 100% similarity between apricot isolates of each species and reference isolates from GenBank (Nos. AF266785, AB367355, DQ118649, and AF266772). The ITS sequence of a P. citrophthora isolate from apricot (IMI 396200) was deposited in GenBank (No. FJ943417). In the summer of 2008, pathogenicity of apricot isolates IMI 396200 (P. citrophthora), IMI 396203 (P. nicotianae), IMI 396201 (P. tropicalis), and IMI 396202 (P. cactorum) was tested on 3-month-old apricot seedlings (10 plants for each isolate) that were transplanted into pots filled with soil prepared by mixing steam-sterilized sandy loam soil (4% vol/vol) with inoculum produced on autoclaved kernel seeds. Ten control seedlings were grown in autoclaved soil. Seedlings were maintained in a screenhouse and watered daily to field capacity. Within 40 days of the transplant, all inoculated seedlings showed leaf chlorosis, wilting, and root rot. Control seedlings remained healthy. All four Phytophthora spp. were reisolated solely from inoculated plants. To our knowledge, this is the first report of Phytophthora root and crown rot of apricot in Italy and of P. tropicalis on this host. References: (1) S. O. Cacciola et al. Plant Dis. 90:680, 2006. (2) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (3) H. Masago et al. Phytopathology 67:425, 1977.

scholarly journals First Report of Phytophthora nicotianae Causing Dianthus chinensis root rot and foliage blight in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Jieying Xu ◽  
Xiao Yang ◽  
Cuiping Wu ◽  
Ziwei Zhou ◽  
Zhenpeng Chen ◽  
...  
Keyword(s):  
Root Rot ◽  
Large Subunit ◽  
Severe Infection ◽  
Average Diameter ◽  
Phytophthora Nicotianae ◽  
Crown Rot ◽  
Molecular Evidence ◽  
First Report ◽  
Whole Plant ◽  
Foliage Blight

Dianthus chinensis is a popular ornamental plant that is widely cultivated in China. From May 2020 to 2021, root rot and foliage blight were observed on approximately 50% groundcover plants at several landscape sites of Xuanwuhu Park and Nanjing Railway Station, China. Symptoms of wilting and chlorosis appeared in the initial stage, and severe infection caused the whole plant to die . To recover the causal pathogen, infected root and leaf samples were cut into 5×5 mm2 squares, surface-disinfected in 70% ethanol for 30 sec, placed onto 10% clarified V8 PARP agar at 25°C . After three days, Phytophthora-like hyphae were visibly emerged from both root and leaf tissues and growing into cV8A. Individual hyphal tips were transferred to new cV8A plates to obtain a total of 10 pure isolates. Colony morphology of all isolates on cV8A had slightly radiate to stellate patterns with cottony aerial mycelia. After four or five days all isolates had identical morphological traits including papillate and noncaducous sporangia on cV8, hyphal swellings, and intercalary and terminal chlamydospores. A representative isolate Pni-dc7 was examined for morphological measurements. Sporangia were mostly ovoid and sometimes obpyriform, averaging 28.9±5.6 µm in length and 24.9±5.8 µm in width (n=30). Chlamydospores were abundant and spherical with an average diameter at 29.2 ± 0.3 µm (n=30). Oogonia were not observed. For sequence analysis, the internal transcribed spacer (ITS) regions and large subunit (LSU) of the nuclear ribosomal RNA gene complex were amplified using the primer pairs ITS1/ITS4 and NL1/NL4 , respectively, while the mitochondrial cytochrome c oxidase subunit II (coxII) gene was amplified using FM58/FM66 (Martin et al. 2003). The ITS sequence of isolate Pni-dc7 (GenBank Acc. No. MZ519893) had a 100% identity to those of P. nicotianae (MH219914, KU172524, MT065839). The LSU sequence (MZ573547) had a 100% identity to those of P. nicotianae (KX250514, MZ348950, HQ665198).The cox2 sequence (MZ519893) had a 100% identity to those of P. nicotianae (MH221078, KJ506439, JF707072). Based on morphological and molecular evidence, Pni-dc7 was identified as P. nicotianae. Pathogenicity tests  were conducted using both detached leaves and whole plants. Asymptomatic leaves were collected from healthy plants.A 5×5 mm2 Pni-dc7-colonized cV8A plug was placed on each wound of five leaves. Sterile agar plugs were used for a non-inoculated control leaf. All six leaves were placed on a wet filter paper in a closed container at 25°C. All inoculated leaves had necrotic tissues around the wounds, the symptoms progressed from spots to the entire leaves after two days . The control leaves remained asymptomatic. In the whole-plant assay, a D. chinensis  plant (approx. 0.3 m in height) was inoculated with 5 mL of zoospore suspension that was mixed into the potting soil(500g). Three plants were inoculated and control plants were treated with sterile distilled water. After two weeks all three inoculated plants in three repeats of the assay had root and crown rot and foliage blight, whereas all control plants remained asymptomatic. P. nicotianae was reisolated from all inoculated plants. This is the first report of P. nicotianae causing root rot and foliage blight on D. chinensis in China. Considering the importance of D. chinensis to both ornamental nursery and landscaping industries in China, diseased plants at the landscape sites were removed to prevent the spread of P. nicotianae to production sites and other landscape locations.

scholarly journals Protection of Citrus Rootstocks Against Phytophthora spp. with a Hypovirulent Isolate of Phytophthora nicotianae

2007 ◽  
Vol 97 (8) ◽  
pp. 958-963 ◽  
Author(s):  
G. C. Colburn ◽  
J. H. Graham
Keyword(s):  
Poncirus Trifoliata ◽  
Phytophthora Nicotianae ◽  
Root Weight ◽  
Post Inoculation ◽  
Phytophthora Root Rot ◽  
Phytophthora Spp ◽  
Naturally Occurring ◽  
Fibrous Roots ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo

Phytophthora root rot of citrus in Florida is caused by Phytophthora nicotianae and P. palmivora. A naturally occurring isolate of P. nicotianae (Pn117) was characterized as hypovirulent on citrus roots. Pn117 infected and colonized fibrous roots, but caused significantly less disease than the virulent isolates P. nicotianae Pn198 and P. palmivora Pp99. Coincident inoculation of rootstock seedlings of Cleopatra mandarin (Citrus reticulata) or Swingle citrumelo (C. paradisi × Poncirus trifoliata) with the hypovirulent Pn117 and the virulent isolates Pn198 and Pp99 did not reduce the severity of disease caused by the virulent Phytophthora spp. When either rootstock was inoculated with the hypovirulent Pn117 for 3 days prior to inoculation with virulent isolates, preinoculated seedlings had significantly less disease and greater root weight compared with seedlings inoculated with the virulent isolates alone. Recovery of the different colony types of Phytophthora spp. from roots of sweet orange (C. sinensis) or Swingle citrumelo was evaluated on semiselective medium after sequential inoculations with the hypovirulent Pn117 and virulent Pp99. Pn117 was isolated from roots at the same level as the Pp99 at 3 days post inoculation. Preinoculation of Pn117 for 3 days followed by inoculation with Pp99 resulted in greater recovery of the hypovirulent isolate and lower recovery of the virulent compared with coincident inoculation.

Preparation of cationic waste paper and its application in poisonous dye removal

2013 ◽  
Vol 67 (11) ◽  
pp. 2560-2567 ◽  
Author(s):  
Fan Yang ◽  
Xiaojie Song ◽  
Lifeng Yan
Keyword(s):  
Low Cost ◽  
Aqueous Suspension ◽  
Order Kinetic ◽  
Acid Orange 7 ◽  
Anionic Dyes ◽  
Experimental Conditions ◽  
Adsorption Models ◽  
Acid Orange ◽  
Initial Ph ◽  
Pseudo Second Order

Cationic paper was prepared by reaction of paper with 2,3-epoxypropyltrimethylammonium chloride in aqueous suspension, and tested as low-cost adsorbent for wastewater treatment. The experimental results revealed that anionic dyes (Acid Orange 7, Acid Red 18, and Acid Blue 92) were adsorbed on the cationic paper nicely. The maximum amount of dye Acid Orange 7 adsorbed on cationic paper was 337.2 mg/g in experimental conditions. The effects of initial dye concentration, temperature, and initial pH of dye solution on adsorption capacity of cationic paper were studied. The pseudo-first-order and pseudo-second-order kinetic models were applied to describe the kinetic data. The Freundlich and Langmuir adsorption models were used to describe adsorption equilibrium. The thermodynamic data indicated that the adsorption process of dye on cationic paper occurred spontaneously.

Phytophthora nicotianae var. parasitica. [Descriptions of Fungi and Bacteria].

1964 ◽  
Author(s):  
G. M. Waterhouse
Keyword(s):  
Geographical Distribution ◽  
Citrus Fruit ◽  
Heavy Rain ◽  
Drainage Water ◽  
Phytophthora Nicotianae ◽  
Crown Rot ◽  
Fruit Rot ◽  
Piper Betle ◽  
Wide Range ◽  
Southern Rhodesia

Abstract A description is provided for Phytophthora nicotianae var. parasitica. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a very wide range of host plants comprising 58 families including: avocado, castor, Cinchona spp., citrus, cotton, eggplant, guava, lucerne, papaw, parsley, pineapple, Piper betle, rhubarb, sesame, strawberry, tomato. DISEASES: Damping-off of seedlings (tomato, castor, citrus, cotton); root rot (citrus, avocado, strawberry, lucerne); crown rot (parsley, rhubarb, strawberry, lucerne); brown stem rot of tobacco; stem canker and tip blight of Cinchona spp. ; leaf blight (castor, sesame, pineapple, Piper betle) and fruit rot (citrus, tomato, guava, papaw, eggplant). GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Mali, Madagascar, Mauritius, Morocco, Nigeria, Sierra Leone, Southern Rhodesia, Tanganyika); Asia (Burma, Ceylon, China, Formosa, India, Israel, Japan, Java, Malaya, Philippines); Australia & Oceania (Australia, Hawaii, Tasmania); Europe (Cyprus, France, Germany, Great Britain, Holland, Ireland, Italy, Poland, Portugal, U.S.S.R.); North America (Bermuda, Canada, Mexico, U.S.A.); Central America & West Indies (Costa Rica, Cuba, El Salvador, Guatemala, Jamaica, Montserrat, Puerto Rico, Trinidad);. South America (Argentina, Brazil, British Guiana, Colombia, Paraguay, Peru, Venezuela). TRANSMISSION: Soil-borne, spreading rapidly after heavy rain or where soil remains moist or water-logged (40: 470). Also recorded in drainage water in India and in reservoirs and canals supplying citrus groves in U.S.A. (23: 45; 39: 24). A method for determining a disease potential index in soil using lemon fruit has been described (38: 4). Also present in testas of seeds from diseased citrus fruit which may infect nursery seedbeds (37: 165).

scholarly journals Efeito do lodo de esgoto na indução de supressividade in vitro a Phytophthora nicotianae

2003 ◽  
Vol 28 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Carolina Leoni ◽  
Raquel Ghini
Keyword(s):  
Triticum Aestivum ◽  
Medicago Sativa ◽  
Phytophthora Nicotianae ◽  
Phytophthora Spp ◽  
Trichoderma Sp ◽  
Aspergillus Sp

Uma alternativa de manejo das doenças causadas por Phytophthora spp. é o uso de matéria orgânica. No presente trabalho foi avaliada a potencialidade do lodo de esgoto na indução de supressividade in vitro a P. nicotianae. O efeito do lodo de esgoto incorporado ao solo na sobrevivência de P. nicotianae foi avaliado mediante um experimento fatorial com dois fatores: doses de lodo de esgoto (0, 10, 20 e 40% p/p) e concentrações de inóculo [0, 10 ou 20 g de grãos de trigo (Triticum aestivum) colonizados kg-1]. Aos 21 dias, quando aumentaram as doses de lodo de esgoto, a sobrevivência de P. nicotianae e os pHs das misturas diminuíram, e as condutividades elétricas (CE) aumentaram. As correlações entre a CE e a sobrevivência do patógeno foram negativas e significativas (P>0,05). Para estudar o efeito dos compostos químicos envolvidos na supressividade, foram obtidos extratos em água, H2SO4 2N e KOH 0,4N de misturas de areia – lodo de esgoto (20% p/p), e foram acrescentados ao meio de cultura e seu efeito avaliado no crescimento das colônias de P. nicotianae. O extrato ácido (H2SO4 2N) do tratamento com 20% de lodo de esgoto inibiu significativamente (P>0,05) o crescimento da colônia do patógeno. O efeito biológico foi estudado mediante isolamento de microrganismos em meio de cultura e seleção por antagonismo. No bioensaio com plântulas de alfafa (Medicago sativa) destacaram-se os isolados F9.1 (Aspergillus sp.) e A12.1 (actinomiceto, não identificado); e no teste de culturas pareadas destacou-se um Trichoderma sp. e dois actinomicetos por antibiose, e um Trichoderma sp. e três Aspergillus sp. por hiperparasitismo.

scholarly journals First Report of Stem and Foliage Blight of Chrysanthemum Caused by Phytophthora drechsleri in the United States

Plant Disease ◽  
2021 ◽  
Author(s):  
Charles Krasnow ◽  
Nancy Rechcigl ◽  
Jennifer Olson ◽  
Linus Schmitz ◽  
Steven N. Jeffers
Keyword(s):  
United States ◽  
South Carolina ◽  
Sequence Similarity ◽  
Morphological Characteristics ◽  
The United States ◽  
Universal Primers ◽  
Broad Host Range ◽  
Pathogenicity Test ◽  
First Report ◽  
Foliage Blight

Chrysanthemum (Chrysanthemum × morifolium) plants exhibiting stem and foliage blight were observed in a commercial nursery in eastern Oklahoma in June 2019. Disease symptoms were observed on ~10% of plants during a period of frequent rain and high temperatures (26-36°C). Dark brown lesions girdled the stems of symptomatic plants and leaves were wilted and necrotic. The crown and roots were asymptomatic and not discolored. A species of Phytophthora was consistently isolated from the stems of diseased plants on selective V8 agar (Lamour and Hausbeck 2000). The Phytophthora sp. produced ellipsoid to obpyriform sporangia that were non-papillate and persistent on V8 agar plugs submerged in distilled water for 8 h. Sporangia formed on long sporangiophores and measured 50.5 (45-60) × 29.8 (25-35) µm. Oospores and chlamydospores were not formed by individual isolates. Mycelium growth was present at 35°C. Isolates were tentatively identified as P. drechsleri using morphological characteristics and growth at 35°C (Erwin and Ribeiro 1996). DNA was extracted from mycelium of four isolates, and the internal transcribed spacer (ITS) region was amplified using universal primers ITS 4 and ITS 6. The PCR product was sequenced and a BLASTn search showed 100% sequence similarity to P. drechsleri (GenBank Accession Nos. KJ755118 and GU111625), a common species of Phytophthora that has been observed on ornamental and vegetable crops in the U.S. (Erwin and Ribeiro 1996). The gene sequences for each isolate were deposited in GenBank (accession Nos. MW315961, MW315962, MW315963, and MW315964). These four isolates were paired with known A1 and A2 isolates on super clarified V8 agar (Jeffers 2015), and all four were mating type A1. They also were sensitive to the fungicide mefenoxam at 100 ppm (Olson et al. 2013). To confirm pathogenicity, 4-week-old ‘Brandi Burgundy’ chrysanthemum plants were grown in 10-cm pots containing a peat potting medium. Plants (n = 7) were atomized with 1 ml of zoospore suspension containing 5 × 103 zoospores of each isolate. Control plants received sterile water. Plants were maintained at 100% RH for 24 h and then placed in a protected shade-structure where temperatures ranged from 19-32°C. All plants displayed symptoms of stem and foliage blight in 2-3 days. Symptoms that developed on infected plants were similar to those observed in the nursery. Several inoculated plants died, but stem blight, dieback, and foliar wilt were primarily observed. Disease severity averaged 50-60% on inoculated plants 15 days after inoculation. Control plants did not develop symptoms. The pathogen was consistently isolated from stems of symptomatic plants and verified as P. drechsleri based on morphology. The pathogenicity test was repeated with similar results. P. drechsleri has a broad host range (Erwin and Ribeiro 1996; Farr et al. 2021), including green beans (Phaseolus vulgaris), which are susceptible to seedling blight and pod rot in eastern Oklahoma. Previously, P. drechsleri has been reported on chrysanthemums in Argentina (Frezzi 1950), Pennsylvania (Molnar et al. 2020), and South Carolina (Camacho 2009). Chrysanthemums are widely grown in nurseries in the Midwest and other regions of the USA for local and national markets. This is the first report of P. drechsleri causing stem and foliage blight on chrysanthemum species in the United States. Identifying sources of primary inoculum may be necessary to limit economic loss from P. drechsleri.

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