scholarly journals First Report of a Root Rot Caused by Rosellinia necatrix on Camellia in Spain

Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 813-813
Author(s):  
J. P. Mansilla ◽  
O. Aguín ◽  
M. C. Salinero
Keyword(s):  
Root Rot ◽  
Triticum Aestivum L ◽  
Phytopathogenic Fungi ◽  
Rosellinia Necatrix ◽  
Camellia Japonica ◽  
First Report ◽  
Plant Parts ◽  
General Decline ◽  
Camellia Species ◽  
White Mycelium

Camellias are widely cultivated in gardens and grown in nurseries for plant and flower production in northwestern Spain. Camellia japonica L. is most frequently grown, but many other camellia species and hybrids are also produced. In spring 1998, plants of Camellia sp. from a garden were observed to be affected by a root fungal pathogen, that formed a white mycelium that covered most of the roots, while aboveground plant parts showed a general decline. Infected roots were macerated and discolored. Fragments of the infected roots were surface-sterilized and placed in petri dishes containing potato dextrose agar and incubated at 24°C in the dark. The fungus formed a white mycelium that turned black in 1 week, developing pyriform swellings characteristic of Rosellinia necatrix Prill (1). To confirm pathogenicity, inoculum of the isolate was produced on wheat (Triticum aestivum L.) seeds autoclaved in glass vessels for 30 min at 120°C. Wheat seed cultures were started from disks of R. necatrix mycelium and grown at 24°C in the dark for 30 days. Pathogenicity tests were conducted on 48 2-year-old plants of the hybrid Camellia × williamsii cv. Mary Phoebe Taylor, which had been grown in 1.5-liter pots (one plant per pot) filled with soil in a glasshouse. The R. necatrix isolate was inoculated by adding 30 g of infected wheat seeds to each pot. The inoculum was mixed thoroughly with the substrate before potting. Another set of pots was left uninoculated, and served as a control. All pots were randomly arranged in a growth chamber at 22 to 24°C with a 12-h photoperiod. Seventeen days after inoculation, aerial symptoms of chlorosis and leaf fall were observed, while control plants remained symptomless. Inoculated plants died 3 months after inoculation. R. necatrix was reisolated from roots of all infected plants. To our knowledge, this is the first report of a root rot of camellia caused by R. necatrix, a pathogen causing white root rot mainly in deciduous fruit crops. Reference: (1) S. Freeman and A. Sztejnberg. Pages 71–73 in: Methods for Research on Soilborne Phytopathogenic Fungi. The American Phytopathological Society, St. Paul, MN, 1992.

scholarly journals Taxonomic composition and incidence of phytopathogenic fungi on the roots of soft spring wheat in the Kansk-Krasnoyarsk forest-steppe

2021 ◽  
Vol 2 (44) ◽  
pp. 22-22
Author(s):  
Alexander Saakian ◽  
◽  
Keyword(s):  
Spring Wheat ◽  
Root Rot ◽  
Bipolaris Sorokiniana ◽  
Triticum Aestivum L ◽  
Wheat Root ◽  
Phytopathogenic Fungi ◽  
Taxonomic Composition ◽  
Forest Steppe ◽  
Root Infection ◽  
Fusarium Spp

The taxonomic composition and incidence of phytopathogenic fungi on the roots of soft spring wheat Triticum aestivum L. of nine varieties of Siberian origin (Altayskaya 70, Altayskaya 75, Krasnoyarskaya 12, Novosibirskaya 15, Novosibirskaya 16, Novosibirskaya 29, Novosibirskaya 31, Novosibirskaya 41 and Svirel) cultivated using wheat and fallow as a predecessor, was studied in the area of Kansk-Krasnoyarsk forest-steppe. Average incidence of fungal root infection was 24%. In plants grown using wheat as a predecessor, the incidence was statistically significantly (p <0.05) higher than in plants grown using fallow as a predecessor (27.3 versus 20.6%). Statistically significant (p <0.05) differences in the prevalence of root infection were revealed between cultivars. The maximal prevalence (33.3 and 32.3%, respectively) on average for the wheat predecessor and fallow was found for the varieties Svirel and Altayskaya 75, the minimal (16.7%) for the varieties Novosibirskaya 16 and Altayskaya 70. The complex of phytopathogenic fungi on the roots is represented by Fusarium spp., Bipolaris sorokiniana and Alternaria spp. (31.4, 44.9 and 23.7% of the pathogenic complex on average for varieties and variants, respectively). The composition of pathogens statistically significantly (p <0.01) depends on the predecessor. In the plants cultivated using wheat as a predecessor, the proportion of Alternaria spp. was higher whereas proportions of Fusarium spp. and Bipolaris sorokiniana were lower. No differences in prevalence and taxonomic composition of root infection between varieties originated from Novosibirsk territory, Krasnoyarsk territory and Altay territory were found. Keywords: SPRING WHEAT, ROOT ROT, KRASNOYARSK TERRITORY, FUSARIUM SPP., BIPOLARIS SOROKINIANA, ALTERNARIA SPP

scholarly journals Take-All Root Rot of St. Augustinegrass: First Report in Mississippi

Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 921-921
Author(s):  
M. Tomaso-Peterson ◽  
L. E. Trevathan ◽  
M. S. Gonzalez
Keyword(s):  
Tall Fescue ◽  
Root Rot ◽  
Potato Dextrose Agar ◽  
Gaeumannomyces Graminis ◽  
Peat Moss ◽  
Infested Soil ◽  
First Report ◽  
Plant Parts ◽  
Home Lawns ◽  
Take All

Take-all root rot has been reported as a destructive disease of St. Augustinegrass home lawns in Florida and Alabama (1). In June 1998 and 1999, St. Augustinegrass home lawns in central Mississippi developed chlorotic, thinning patches ranging from 0.5 to 4.5 m in diameter. By August of each summer, plants within affected patches were necrotic and dead. Roots of affected St. Augustinegrass were necrotic and shorter than those of unaffected plants; nodes on stolons were necrotic, and lesions developed on internodes. Ectotrophic runner hyphae and dark brown, lobed hyphopodia were visible on roots and aboveground plant parts, respectively. Symptomatic tissues collected from St. Augustinegrass home lawns were plated onto potato dextrose agar (PDA); the incitant of take-all root rot, Gaeumannomyces graminis(Sacc.) Arx & Olivier var. graminis, was isolated. Verification of G. graminis var. graminis was based on colony morphology and taxonomic identification consistent with the description by Walker (2). G. graminis var. graminis isolated from symptomatic St. Augustinegrass was grown on sterile tall fescue seed and incorporated into sterile sand/peat moss mix. Asymptomatic St. Augustinegrass sprigs were washed, and roots were removed prior to planting in infested and noninfested soil. Plants were cultured in the greenhouse for 60 days. St. Augustinegrass planted into noninfested soil was asymptomatic while plants collected from G. graminis var. graminis-infested soil were symptomatic for take-all root rot. Crowns and roots of affected plants were necrotic; leaves were chlorotic and necrotic. Both runner hyphae and lobed hyphopodia were visible. G. graminis var. graminis was reisolated from symptomatic tissues and confirmed as the incitant of take-all root rot. This is the first report of take-all root rot of St. Augustinegrass in Mississippi. References: (1) M. Elliott. Plant Dis. 77:206, 1993. (2) J. Walker. Trans. Br. Mycol. Soc. 58:427, 1972.

scholarly journals First Report of White Root Rot Caused by Rosellinia necatrix on Persea americana in South Africa

Plant Disease ◽  
2018 ◽  
Vol 102 (9) ◽  
pp. 1850 ◽  
Author(s):  
N. van den Berg ◽  
J. Hartley ◽  
J. Engelbrecht ◽  
Z. Mufamadi ◽  
Z. van Rooyen ◽  
...  
Keyword(s):  
South Africa ◽  
Root Rot ◽  
Persea Americana ◽  
Rosellinia Necatrix ◽  
White Root Rot ◽  
First Report

scholarly journals First Report of Stem Rot and Wilt of Sunflower Caused by Sclerotinia minor in Spain

Plant Disease ◽  
2002 ◽  
Vol 86 (6) ◽  
pp. 697-697
Author(s):  
M. L. Molinero-Ruiz ◽  
J. M. Melero-Vara
Keyword(s):  
Helianthus Annuus ◽  
Root Rot ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Potato Dextrose Agar ◽  
Stem Rot ◽  
Sclerotinia Minor ◽  
Stem Base ◽  
First Report ◽  
White Mycelium

In 2001, sunflower (Helianthus annuus L.) plants with symptoms of stem and root rot and wilt were observed in Soria, Spain. Light brown, water-soaked lesions developed on the collar of infected plants and extended along the stem, affecting the pith and causing early and sudden wilt. White mycelium and sclerotia (0.5 to 2 mm long) formed in the pith of stems. The sclerotia were disinfested in NaClO (10% vol/vol) for 1 min, transferred to potato dextrose agar (PDA), and incubated at 20°C. The fungus consistently obtained was identified as Sclerotinia minor Jagger (1). Pathogenicity was confirmed in a greenhouse experiment (15 to 25°C, 13 h light). Seven-week-old plants of six genotypes of sunflower (‘Peredovik’, HA89, HA821, HA61, RHA274, and HA337) were inoculated by placing one PDA disk with active mycelial growth adjacent to each basal stem just below the soil line and covering it with peat/sand/silt (2:2:1, vol/vol). Six plants of each genotype were inoculated without wounding, and another six were inoculated immediately after stem base wounding with a scalpel; six wounded and uninoculated plants were used as controls. First symptoms (wilting) appeared 4 days after inoculation in all genotypes. Two weeks after inoculation, the percentage of dead plants ranged from 33 to 92% (depending on cultivar), white mycelium was observed at the base of affected plants, and sclerotia were present in the pith of diseased plants. There was no effect of plant wounding on disease incidence or severity, and the fungus was reisolated from inoculated plants. To our knowledge, this is the first report of S. minor in Spain. Reference: (1) L. M. Kohn. Mycotaxon IX 2:365, 1979.

scholarly journals First Report of Rosellinia necatrix Causing White Root Rot in Mango Trees in Spain

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2639 ◽  
Author(s):  
I. Arjona-Girona ◽  
C. J. López-Herrera
Keyword(s):  
Root Rot ◽  
Rosellinia Necatrix ◽  
White Root Rot ◽  
First Report

scholarly journals First Report of Rhizoctonia solani Causing a Disease of Sunflower in India

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 488-488 ◽  
Author(s):  
K. Srinivasan ◽  
S. Visalakchi
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Crown Rot ◽  
Pathogenicity Test ◽  
American Phytopathological Society ◽  
First Report ◽  
Leaf Yellowing ◽  
Crown Tissue ◽  
Symptomatic Tissue ◽  
White Mycelium

During the spring of 2009, symptoms including leaf yellowing and wilting, root rot, and death of plants were noted in sunflower (Helianthus annuus L.) crops in Dharmapuri District, Tamilnadu, India. In some fields, approximately 30% of the plants were affected. The disease began when plants were approximately 10 weeks old and occurred on scattered or adjacent plants. The presence of white mycelium was observed on necrotic crowns. Symptomatic tissue was surface disinfested in 70% alcohol for 30 s and 0.5% sodium hypochlorite for 1 min and plated onto potato dextrose agar (PDA) (1). One isolate (coded SV001) had near right-angle branching with basal constriction and adjacent septa and sclerotia typical of Rhizoctonia spp. (2). Cream-colored colonies produced irregular, light brown sclerotia that were 3.0 to 7.3 mm (average 3.8 mm) in diameter. Hyphae were 6.8 to 7.0 μm (average 6.9 μm) wide and multinucleate (8 to 15 nuclei per cell). On the basis of hyphal anastomosis with several known AG testers, the fungus was characterized as Rhizoctonia solani Kühn AG-IV (3). One culture was deposited at the Madras University Botany Laboratory, Center for Advanced Studies in Botany, University of Madras, Chennai, India. In a pathogenicity test, R. solani SV001 was grown on PDA for 5 days at 24°C in the dark. Five-millimeter-diameter disks were placed at the base of sunflower plants (cv. Mordan). Four sunflower plants in each of three pots were inoculated; noninoculated plants served as controls. Plants were placed in a glasshouse maintained at 25 to 27°C. Inoculated plants developed yellow foliage and crown rot and root rot symptoms after 7 to 12 days and died in 17 to 20 days. No symptoms were observed on noninoculated plants. The pathogen was reisolated from fragments of necrotic crown tissue of inoculated plants. To our knowledge, this is the first report of R. solani AG-IV causing a disease of sunflower plants in India. References: (1). R. C. Fenille et al. Plant Pathol. 54:325, 2005. (2). J. R. Parmeter et al. Phytopathology 59:1270, 1969. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St Paul, MN, 1991.

scholarly journals First Report of Rosellinia necatrix Causing White Root Rot on Avocado in Italy

Plant Disease ◽  
2021 ◽  
Author(s):  
A. Fiorenza ◽  
D. Aiello ◽  
G. R. Leonardi ◽  
A. Continella ◽  
G. Polizzi
Keyword(s):  
Root Rot ◽  
Rosellinia Necatrix ◽  
White Root Rot ◽  
First Report

scholarly journals First Report of White Root Rot Caused by Rosellinia necatrix on Aronia melanocarpa in Korea

Plant Disease ◽  
2017 ◽  
Vol 101 (1) ◽  
pp. 253-253 ◽  
Author(s):  
I. Y. Choi ◽  
H. T. Oh ◽  
W. H. Lee ◽  
S. E. Cho ◽  
H. D. Shin
Keyword(s):  
Root Rot ◽  
Rosellinia Necatrix ◽  
White Root Rot ◽  
First Report ◽  
Aronia Melanocarpa

Rosellinia necatrix. [Descriptions of Fungi and Bacteria].

1972 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Geographical Distribution ◽  
Root Rot ◽  
Central Africa ◽  
Citrus Reticulata ◽  
Malus Pumila ◽  
Rosellinia Necatrix ◽  
Fruit Crops ◽  
White Root Rot ◽  
Cynara Scolymus ◽  
White Mycelium

Abstract A description is provided for Rosellinia necatrix. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Acacia, almond, Annona, apple, apricot, artichoke, avocado, barley, bean, beet, Begonia, blackberry, Boemeria nivea, cherry, chestnut, Citrus, coffee, Cotoneaster, currants, Cyclamen neapolitanum, Cynara scolymus, elm, fig, Genista monosperma, jasmine, lucerne, maize, mulberry, Narcissus, oak, olive, peach, pear, peony, pepper (black), pistachio, Pittosporum crassifolium, plum, poplar, potato, quince, rose, Salix, sorghum, strawberry, tea, tulip, Vaucheria, vine, violet, walnut, wheat, Zantedeschia. DISEASE: White root rot of temperate fruit crops particularly grapevine (Vitis viniferd). apple (Malus pumila) and mulberry (Morus spp.). Probably a plurivorous pathogen: it has also been reported causing disease in artichoke (Cynara scolymus; 7: 218), coffee (Coffea spp. ; 36: 318), lucerne (Medicago sativa; 21: 23), mandarin (Citrus reticulata: 45, 3299), ramie (Boehmeria nivea) and tea (Camellia sinensis; 35: 330). The roots (young ones of tea being attacked first) are invested with a white mycelium which on older roots turns to brown and almost black; superficial black sclerotia may occur and the hyphae are swollen near the septa. Wilt and death of the tree may be slow or fairly rapid and infection is generally confined to the roots. GEOGRAPHICAL DISTRIBUTION: Widespread in Europe, W. Asia, central Africa and also occurs in Argentina, Brazil, Mexico, Philippines, Uruguay and USA (CMI Map 306, ed. 2, 1965). Additional records not yet mapped are: Colombia, Dominican Republic, India (Himachal Pradesh), New Zealand, UK (Scilly Is.). TRANSMISSION: Plant roots and debris in soil. There appears to be no evidence for spread by spores.

scholarly journals First Report of White Root Rot of Japanese Serissa Caused by Rosellinia necatrix in Taiwan

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1512-1512
Author(s):  
W. W. Hsiao ◽  
C. H. Fu ◽  
C. Y. Chen ◽  
E. J. Sun
Keyword(s):  
Root Rot ◽  
Plant Diseases ◽  
Rosellinia Necatrix ◽  
White Root Rot ◽  
First Report ◽  
Root Rots ◽  
Old Japanese ◽  
Pure Cultures ◽  
The Republic ◽  
Central Taiwan

Japanese serissa (Serissa japonica (Thunb.) Thunb.) is a very popular ornamental in Taiwan. During the summer of 2005, serissa plants in a central Taiwan nursery had decaying roots, leaf yellowing, and were wilting. Wilted plants had white fan-like mycelium under the bark. The disease caused 70% loss of seedlings at the nursery. Associated synnemata were rigid, erect, dark, setaceous, 0.8 to 2.1 mm long, 90 to 200 μm wide, and tapering to enlarged whitish gray heads composed of geniculate conidiophores and conidia. Conidia were 3.1 to 5.8 × 2.6 to 3.4 μm, unicellular, hyaline, and subglobal with a truncated base. Root rots were washed, disinfested for 1 min in 0.5% NaOCl, cut into 3 mm3 pieces, plated on Merck (Darmstadt, Germany) potato dextrose agar (PDA) amended with 100 ppm of ampicillin (Sigma, St. Louis, MO), and incubated at 24°C in the dark until hyphae emerged. Single hyphal tips were transferred to PDA, and two isolates were established as pure cultures. Mycelia were cut, stained with 1% cotton blue in lactophenol, and pear-shaped hyphal swellings adjacent to the septa were observed. According to these hyphal, synnematal, and conidial characteristics, the fungus was identified as Dematophora necatrix Hartig, the anamorph of Rosellinia necatrix Prill. Inoculum for pathogenicity tests were produced on oat-wheat medium composed of 20 ml of oat grain and 20 ml of wheat grain, mixed, and soaked in water for 3 h. The grains were placed in 200-ml flasks, autoclaved at 121°C for 30 min, inoculated with two isolates of D. necatrix separately, and grown for 14 days. Six 3-month-old Japanese serissa seedlings were grown in pots. The grain inoculum was added to unsterilized field soil and the plants were transplanted into this mix. Control plants were transplanted into a similar mix without the inoculum. Two replicates were used for a total of 24 inoculated plants and 24 control plants. All plants were kept in a growth chamber at 25 to 35°C with 20 min of irrigation per day, 12 h of irradiation, and relative humidity at more than 95%. Inoculated plants developed root rots after 1 month, and after 4 months, all plants were dead, while control plants remained healthy. D. necatrix was reisolated, hyphal characteristics confirmed, and synnemata were observed on collars of dead plants. The teleomorph was not formed by our cultures, and the identification of Rosellinia necatrix was confirmed by molecular studies. The nuclear ribosomal internal transcribed spacer (ITS) amplified with two primers, ITS1 and ITS4, from our representative isolate demonstrated 99.63, 99.81, and 99.27% similarity to two R. necatrix isolates from Japan and one R. necatrix isolate from Italy, respectively. This disease has been reported on many species of plants (1), but to our knowledge, this is the first report of white root rot of Japanese serissa seedlings caused by R. necatrix in Taiwan. Reference: (1) S. T. Su et al. List of Plant Diseases in Taiwan. The Phytopathological Society of the Republic of China, 2002.

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