SUDDEN WILTING OF POINSETTIA (EUPHORBIA PULCHERRIMA) CAUSED BY PYTHIUM APHANIDERMATUM

1978 ◽  
Vol 58 (2) ◽  
pp. 569-570 ◽  
Author(s):  
A. T. BOLTON
Keyword(s):  
Pythium Aphanidermatum ◽  
Euphorbia Pulcherrima ◽  
Complete Necrosis ◽  
Pathogenicity Tests

Poinsettia (Euphorbia pulcherrima Willd.) cuttings imported from California became severely wilted 5–6 wk after planting at Ottawa. Isolations made from these plants yielded cultures of Pythium aphanidermatum (Edson) Fitzp. Pathogenicity tests demonstrated that this fungus caused severe wilting of poinsettia cuttings in 2 days and complete necrosis in 6 days.

scholarly journals First Report of Collar and Stem Rot Caused by Pythium aphanidermatum on Figmarigold (Lampranthus sp.) in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 672-672 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
P. Pensa ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Its Region ◽  
The United States ◽  
Pythium Aphanidermatum ◽  
Peat Moss ◽  
Fluorescent Light ◽  
Rooted Cuttings ◽  
First Report ◽  
Light Yellow ◽  
Pathogenicity Tests

Lampranthus sp. N.B. Brown (figmarigold) of the Aizoaceae family is used as groundcover in gardens. In October of 2008, severe outbreaks of a previously unknown rot were observed in a nursery located in Liguria, near Savona (northern Italy), on 35-day-old rooted cuttings grown in a peat substrate. Approximately 50% of rooted cuttings of red-flowered cultivars were affected. Lesions on collars and young stems were brown, water soaked, and soft. Plants eventually collapsed as roots rotted. Thin, aerial hyphae were visible on the surface of the stems and substrate. Later, a thick, light yellow, mycelial mat surrounded infected plants. Tissue fragments were excised from the margins of the lesions, dipped in a solution containing 1% sodium hypochlorite, and plated on potato dextrose agar and a medium selective for Oomycetes (4). Plates were incubated under constant fluorescent light at 23 ± 1°C for 4 to 5 days. Hyphae of five isolates grown on V8 medium were aseptate and 4.2 to 7.9 (average 6.2) μm wide. Sporangia consisted of complexes of swollen hyphal branches. Oogonia were globose, smooth, and 23.5 to 28.0 (average 25.9) μm in diameter. Antheridia were barrel shaped, intercalary, and diclinous. Oospores were globose and 19.4 to 23.6 (average 21.4) μm in diameter. The internal transcribed spacer (ITS) region of rDNA of a single isolate (DB24112008) was amplified with primers ITS4/ITS6 and sequenced. A BLAST analysis (1) in GenBank of the 1,074-bp segment showed a 100% homology with the sequence of Pythium aphanidermatum (Accession No. EU245039). The nucleotide sequence has been assigned the GenBank Accession No. FJ492745. Pathogenicity tests were performed twice on a red-flower cultivar of a Lampranthus sp. grown in 1-liter pots containing a peat moss substrate infested with wheat and hemp kernels colonized with one isolate of P. aphanidermatum at a rate of 20 g/liter. Ten plants were grown in infested media and 10 plants were grown in noninfested media. Greenhouse temperatures were 18 to 24°C. The first symptoms of stem and root rot developed 15 days later, while control plants remained healthy. P. aphanidermatum was consistently reisolated from the lesions. To our knowledge, this is the first report of P. aphanidermatum on a Lampranthus sp. in Italy. The disease has been reported in Japan (3) in 2008, while in the United States, a Pythium sp. was reported on L. aureus and L. glomeratus (2). Currently, the economic importance of Pythium rot on figmarigold in Italy is still limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. F. Farr et al. Fungi on Plants and Products in the United States. The American Phytopathological Society, St Paul, MN, 1989. (3) H. Kawarazachi et al. J. Gen. Plant Pathol. 74:94, 2008. (4) H. Masago et al. Phytopathology, 67, 425, 1977.

scholarly journals Evaluation of Poinsettia Cultivars for Resistance to Pythium Root Rot Caused by Pythium aphanidermatum

2017 ◽  
Vol 27 (6) ◽  
pp. 805-812 ◽  
Author(s):  
Emma C. Lookabaugh ◽  
Brian Whipker ◽  
Barbara B. Shew
Keyword(s):  
North Carolina ◽  
Host Resistance ◽  
Root Rot ◽  
Partial Resistance ◽  
Integrated Management ◽  
Pythium Aphanidermatum ◽  
Euphorbia Pulcherrima ◽  
Predominant Species ◽  
Pythium Root Rot ◽  
Color Response

Pythium aphanidermatum is the predominant species causing pythium root rot of commercially grown poinsettia (Euphorbia pulcherrima) in North Carolina. Pythium root rot is primarily managed with strict sanitation practices and preventative fungicide applications. To determine if host resistance could play a role in the integrated management of pythium root rot, information on the susceptibility of commercial poinsettia cultivars is needed. Commercially available poinsettia cultivars were inoculated with P. aphanidermatum 3 weeks after transplant and evaluated for resistance to pythium root rot 2 months later. Thirty-four cultivars were evaluated for resistance in 2014 and 58 cultivars were evaluated in 2015, for a total of 62 cultivars evaluated. Twenty-nine cultivars were evaluated in both years. Most cultivars were susceptible to pythium root rot and none were completely resistant. However, several cultivars demonstrated partial resistance to pythium root rot. Interspecific hybrid cultivars, including Luv U Pink, had a higher level of partial resistance when compared with conventional cultivars. Partial resistance varied across bract color, response time, and plant vigor groupings. Overall, 6 of 13 partially resistant cultivars identified in 2015 had red bracts. These results indicate that growers should be able to choose among several red bract cultivars that have higher-level partial resistance to pythium root rot than others.

scholarly journals First Report of Damping-off Caused by Pythium aphanidermatum on Leaf Beet (Beta vulgaris subsp. vulgaris) in Italy

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 292-292 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
G. Ortu ◽  
M. L. Gullino
Keyword(s):  
Beta Vulgaris ◽  
Its Region ◽  
Soft Rot ◽  
Pythium Aphanidermatum ◽  
Morphological Characters ◽  
Fluorescent Light ◽  
Damping Off ◽  
First Report ◽  
Pathogenicity Tests ◽  
Crown And Root Rot

During July 2010, symptoms of crown and root rot were observed on leaf beet (Beta vulgaris L. subsp. vulgaris) grown in a commercial field near Torino (northern Italy). The first symptoms developed 25 days after sowing with temperatures ranging from 25 to 30°C, and 20% of plants were affected. Affected plants were stunted and leaves showed chlorosis and suddenly wilted. The collar and young stems were affected first and appeared brown, water-soaked, and were characterized by a soft rot. Eventually, all affected plants collapsed. Thin aerial mycelia were visible on the surface of the infected plants if maintained at a high relative humidity. Tissue fragments of 1 mm2 were excised from the margins of the lesions, dipped in a solution containing 1% sodium hypochlorite, and plated on potato dextrose agar (PDA) and on a medium selective for oomycetes (2). Plates were incubated under constant fluorescent light at 22 ± 1°C for 5 days. Five isolates, grown on V8 medium (vegetable mix 300 g; agar 15 g; CaCO3 1.5 g; distilled water 1 liter) and observed under light microscope showed the morphological characters of Pythium aphanidermatum (3). This result was confirmed by PCR and sequence analysis. The internal transcribed spacer (ITS) region of rDNA of a single isolate (Py 7/10) was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 815 bp segment showed a 99% homology with the sequence of P. aphanidermatum (GenBank Accession JN695786). The nucleotide sequence has been assigned to the GenBank Accession JX462954. Pathogenicity tests were performed twice on B. vulgaris subsp. vulgaris grown in 2-liter pots, containing a steam disinfested organic peat substrate (70% black peat, 30% white peat, pH 5.5 to 6, N 110 to 190 mg L–1, P2O5 140 to 230 mg L–1, K2O 170 to 280 mg L–1), infested with wheat and hemp kernels colonized with a strain of P. aphanidermatum at a rate of 1 g L–1. Ten seeds per pot were sown in four pots filled with the infested medium, while the same number of seeds were sown in non-infested substrate. Plants were kept in two growth chambers, at 20 and 27°C. The first symptoms developed 7 days after the artificial inoculation. After 20 days, 70% of plants were infected at 27°C, while 10% were affected at 20°C. Control plants remained healthy at both temperatures. P. aphanidermatum was consistently reisolated from the lesions. To our knowledge, this is the first report of damping off of B. vulgaris subsp. vulgaris caused by P. aphanidermatum in Italy. The importance of the disease, at present limited, could increase in areas where leaf beet is intensively grown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) H. Masago et al. Phytopathology 67:425, 1977. (3) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, Florida, 2002.

Ximena, variedad de nochebuena (Euphorbia pulcherrima Willd. ex Klotzsch) para decorar espacios de interior

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Jaime Canul Ku ◽  
Faustino García-Pérez ◽  
Edwin J. Barrios-Gómez ◽  
Sandra E. Rangel-Estrada
Keyword(s):  
Euphorbia Pulcherrima

Objetivo: Describir la variedad de nochebuena Ximena en base a directrices de la UPOV y evaluar su comportamiento con un productor cooperante en el estado de Morelos.Diseño/metodología/aproximación: La variedad se generó mediante los métodos genotécnicos de hibridación, selección recurrente y uso de la técnica de injerto. La descripción varietal se realizó en base al documento de la Unión para la Protección de las Obtenciones Vegetales (UPOV). El diseño experimental utilizado fue un completamente al azar con 10 repeticiones. Se registraron caracteres vegetativos y de bráctea de la planta. La información se estudió mediante análisis de varianza y prueba de comparación de medias Tukey (P? 0.05).Resultados: Ximena presenta porte alto, de amplitud grande con ramificación intermedia. La hoja de forma oval, larga y ancha con peciolo de longitud media. Brácteas de forma elíptica, color rojo, sin torsión y rugosidad entre los nervios. La anchura de la cima es media, glándulas del ciatio de color amarillo de tamaño medio sin alguna deformación. La respuesta de Ximena fue estadísticamente similar a los dos testigos en diámetro del tallo, número de entrenudos, ancho de hoja, longitud de peciolo de hoja y bráctea. En cambio, fue superior estadísticamente en longitud de bráctea, amplitud de dosel de bráctea y diámetro de ciatio.Limitaciones del estudio/implicaciones: La variedad se mantiene como planta madre, a partir de la cual se van a establecer cultivos comerciales. Por lo que, requiere adecuada nutrición y condiciones que no permitan su diferenciación floral.Hallazgos/conclusiones: El comportamiento y arquetipo de Ximena fue comparable a la de variedades comerciales, posee características estéticas que demanda el mercado, puede ser competitiva y se considera candidata para diversificar la oferta de plantas de nochebuena en la temporada de navidad.

Photoperiod and Temperature Influence on Flower Initiation and Development for Euphorbia pulcherrima Grown Under Florida Conditions

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 509a-509
Author(s):  
C.E. Wieland ◽  
J.E. Barrett ◽  
D.G. Clark ◽  
G. J. Wilfret
Keyword(s):  
Subsequent Development ◽  
Flower Initiation ◽  
Euphorbia Pulcherrima ◽  
Floral Initiation ◽  
Temperature Influence ◽  
Average Temperature ◽  
Long Day ◽  
Time To Initiation ◽  
Growth Room ◽  
Maximum Temperatures

Four poinsettia cultivars were grown in glass greenhouses in Gainesville, Fla., in the Fall 1997 to evaluate differences in floral initiation and subsequent development. Three means of regulating photoperiod were 1) natural days 2) long-day lighting to 6 Oct. and then natural days (lights out) 3) long-day lighting to 6 Oct., and then short-day conditions by black cloth for 15 h (black cloth). At 2-day intervals, sample meristems were collected and examined for initiation of reproductive development. Average minimum and maximum temperatures during the first two weeks of October were 22 and 29 °C, respectively, with an average temperature of 25.3 °C. The overall average temperature was 23.2 °C from planting to anthesis. Differences in anthesis dates among cultivars were primarily due to time to initiation vs. rate of development. Under natural days, `Lilo' initiated first on 8 Oct. and `Freedom', `Peterstar', and `Success', followed by 6, 8, and 18 days, respectively. Lights out resulted in `Lilo' initiating 17 Oct., followed by `Freedom', `Peterstar', and `Success' initiating 7, 12, and 15 days later, respectively. Differences between cultivars in time of initiation was reduced under black cloth, where `Lilo' initiated 14 Oct., followed by `Freedom' 2 days later, and `Peterstar' and `Success' 7 days afterward. Initiation was positively correlated to visible bud and anthesis. First color was positively correlated to initiation and visible bud, with the exception of `Lilo'. Growth room studies conducted using various high temperatures and photoperiods indicated similar trends.

scholarly journals Incidence and Etiology of Postharvest Fungal Diseases Associated with Bulb Rot in Garlic (Alllium sativum) in Spain

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1063
Author(s):  
Laura Gálvez ◽  
Daniel Palmero
Keyword(s):  
Negative Impact ◽  
Fusarium Species ◽  
Fungal Species ◽  
Postharvest Disease ◽  
Dry Rot ◽  
Fusarium Dry Rot ◽  
Causative Agents ◽  
Postharvest Handling ◽  
Pathogenicity Tests ◽  
Bulb Rot

In recent years, different postharvest alterations have been detected in garlic. In many cases, the symptoms are not well defined, or the etiology is unknown, which further complicates the selection of bulbs during postharvest handling. To characterize the different symptoms of bulb rot caused by fungi, garlic bulb samples were collected from six Spanish provinces in two consecutive years. Eight different fungal species were identified. The most prevalent postharvest disease was Fusarium dry rot (56.1%), which was associated with six Fusarium species. Fusarium proliferatum was detected in more than 85% of symptomatic cloves, followed by F. oxysporum and F. solani. Pathogenicity tests did not show a significant correlation between virulence and mycotoxin production (fumonisins, beauvericin, and moniliformin) or the mycelial growth rate. Penicillium allii was detected in 12.2% of the samples; it was greatly influenced by the harvest season and garlic cultivar, and three different morphotypes were identified. Stemphylium vesicarium and Embellisia allii were pathogenic to wounded cloves. Some of the isolated fungal species produce highly toxic mycotoxins, which may have a negative impact on human health. This work is the first to determine the quantitative importance, pathogenicity, and virulence of the causative agents of postharvest garlic rot in Spain.

scholarly journals Morphology Characterization, Molecular Phylogeny, and Pathogenicity of Diaporthe passifloricola on Citrus reticulata cv. Nanfengmiju in Jiangxi Province, China

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 218
Author(s):  
Chingchai Chaisiri ◽  
Xiang-Yu Liu ◽  
Wei-Xiao Yin ◽  
Chao-Xi Luo ◽  
Yang Lin
Keyword(s):  
Phylogenetic Analyses ◽  
Citrus Fruit ◽  
Epidemiological Studies ◽  
Morphological Characterization ◽  
Jiangxi Province ◽  
Citrus Reticulata ◽  
Fruit Storage ◽  
Pathogenicity Tests ◽  
Rot Disease ◽  
Morphology Characterization

The Nanfengmiju (Citrus reticulata cv. Nanfengmiju), a high-quality local variety of mandarin, is one of the major fruit crops in Jiangxi Province, China. Citrus melanose and stem-end rot, two common fungal diseases of Nanfengmiju, are both caused by Diaporthe spp. (syn. Phomopsis spp.). Identification of the Diaporthe species is essential for epidemiological studies, quarantine measures, and management of diseases caused by these fungi. Melanose disease was observed on Nanfengmiju fruit in Jiangxi Province of China in 2016. Based on morphological characterization and multi-locus phylogenetic analyses, three out of 39 isolates from diseased samples were identified as D. passifloricola. Since these three isolates did not cause melanose on citrus fruit in the pathogenicity tests, they were presumed to be endophytic fungi present in the diseased tissues. However, our results indicate that D. passifloricola may persist as a symptom-less endophyte in the peel of citrus fruit, yet it may cause stem-end if it invades the stem end during fruit storage. To the best of our knowledge, this is the first report of D. passifloricola as the causal agent of the stem-end rot disease in Citrusreticulata cv. Nanfengmiju.

scholarly journals In-depth evaluation of root infection systems using the vascular fungus Verticillium longisporum as soil-borne model pathogen

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Christian Fröschel
Keyword(s):  
Marker Genes ◽  
Root Infection ◽  
Root Pathogen ◽  
Verticillium Longisporum ◽  
Indole Glucosinolates ◽  
Advantages And Disadvantages ◽  
Root Pathogens ◽  
Pathogenicity Tests ◽  
Microbe Interactions ◽  
Defence Strategies

Abstract Background While leaves are far more accessible for analysing plant defences, roots are hidden in the soil, leading to difficulties in studying soil-borne interactions. Inoculation strategies for infecting model plants with model root pathogens are described in the literature, but it remains demanding to obtain a methodological overview. To address this challenge, this study uses the model root pathogen Verticillium longisporum on Arabidopsis thaliana host plants and provides recommendations for selecting appropriate infection systems to investigate how plants cope with root pathogens. Results A novel root infection system is introduced, while two existing ones are precisely described and optimized. Step-by-step protocols are presented and accompanied by pathogenicity tests, transcriptional analyses of indole-glucosinolate marker genes and independent confirmations using reporter constructs. Advantages and disadvantages of each infection system are assessed. Overall, the results validate the importance of indole-glucosinolates as secondary metabolites that limit the Verticillium propagation in its host plant. Conclusion Detailed assistances on studying host defence strategies and responses against V. longisporum is provided. Furthermore, other soil-borne microorganisms (e.g., V. dahliae) or model plants, such as economically important oilseed rape and tomato, can be introduced in the infection systems described. Hence, these proven manuals can support finding a root infection system for your specific research questions to further decipher root-microbe interactions.

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