Pathogenicity of Myrothecium roridum and Rhizoctonia solani in nursery coffee plants

Stem cankers and root rot of coffee plants were detected in the nurseries. Proliferation of adventitious roots at the base of the stems was also observed. Several fungi were isolated from the root and stem lesions and pathogenicity trials were conducted under the humid conditions of the shadehouse. Typical disease symptoms were reproduced by Myrothecium roridum and Rhizoctonia solani in the root and in the stem of the inoculated plants.

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First Report of Colletotrichum truncatum Causing Stem Cankers on Jatropha curcas in Burkina Faso

Plant Disease ◽

10.1094/pdis-02-14-0181-re ◽

2015 ◽

Vol 99 (1) ◽

pp. 14-20 ◽

Cited By ~ 2

Author(s):

C. A. Ellison ◽

A. Sawadogo ◽

S. Braman ◽

S. Nacro

Keyword(s):

Burkina Faso ◽

Jatropha Curcas ◽

Management Practices ◽

Fruit Production ◽

Multiple Infections ◽

Colletotrichum Truncatum ◽

Yield Losses ◽

Disease Symptoms ◽

Stem Lesions ◽

Stem Cankers

A new disease was identified on the biofuel crop Jatropha curcas in 2012 in Burkina Faso that is causing serious yield losses. The disease was found to be widespread in both Sissili and Comoé Provinces. It causes characteristic leaf lesions, fruit necrosis, and cankers on young stems and branches. There was evidence of multiple infections on plants over the growing season, with regrowth evident from below old cankers, but there was little fruit production from infected branches. A detailed monitoring and assessment was undertaken of the disease progress in a severely infected field, over a 7-week period. The disease symptoms progressed from chlorosis through a necrotic phase and, in approximately 83% of replicates, stem cankers developed that resulted in dieback and lodging of branches. Colletotrichum truncatum and a member of the species complex C. gloeosporioides sensu lato were consistently isolated from fresh stem samples showing early symptoms (chlorosis). Koch's postulates were undertaken, to establish the pathogenicity of the two species. No symptoms were observed on plants inoculated with C. gloeosporioides; however, leaf and stem lesions developed after inoculation with C. truncatum, which was reisolated from the diseased tissue, confirming it as the disease-causing agent. Preliminary management practices for the disease are proposed.

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First Report of Crown and Root Rot Caused by Rhizoctonia solani AG-4 on Banana Passionflower (Passiflora mollissima) in Italy

Plant Disease ◽

10.1094/pdis-05-11-0411 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1194-1194 ◽

Cited By ~ 2

Author(s):

G. Polizzi ◽

D. Aiello ◽

V. Guarnaccia ◽

A. Panebianco ◽

P. T. Formica

Keyword(s):

Rhizoctonia Solani ◽

Root Rot ◽

Disease Incidence ◽

Morphological Characteristics ◽

Fluorescent Light ◽

Disease Symptoms ◽

First Report ◽

Pathogenicity Tests ◽

Crown And Root Rot ◽

Safranin O

The genus Passiflora (Passifloraceae family) contains more than 500 species and several hybrids. In Italy, some of these species and hybrids are grown as ornamental evergreen vines or shrubs. During August and September 2010, a crown and root rot was observed in a stock of approximately 6,000 potted 2-year-old plants of Passiflora mollissima (Kunth) Bailey, commonly known as the banana passionflower, in a nursery located in eastern Sicily (southern Italy). Disease incidence was approximately 20%. Disease symptoms consisted of water-soaked lesions at the crown and a root rot. Successively, older crown lesions turned light brown to brown and expanded to girdle the stem. As crown and root rot progressed, basal leaves turned yellow and gradually became necrotic and infected plants wilted and died. A fungus with mycelial and morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from crown lesions and brown decaying roots when plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 μg/ml. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Mycelium was branched at right angles with a septum near the branch with a slight constriction at the branch base. Hyphal cells removed from 10 representative cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400. Anastomosis groups were determined by pairing isolates on 2% water agar in petri plates (4). Pairings were made with tester strains of AG-1, AG-2, AG-3, AG-4, AG-5, AG-6, and AG-11. Anastomosis was observed only with tester isolates of AG-4 (3). Pathogenicity tests were performed on container-grown, healthy, 3-month-old cuttings. Twenty plants of P. mollissima were inoculated near the base of the stem with five 1-cm2 PDA plugs from 5-day-old mycelial plugs obtained from two representative cultures. The same number of plants served as uninoculated controls. Plants were maintained at 25°C and 95% relative humidity with a 12-h fluorescent light/dark regimen. Wilt symptoms due to crown and root rot, identical to ones observed in the nursery, appeared 7 to 8 days after inoculation with either of the two isolates and all plants died within 20 days. No disease was observed on control plants. R. solani AG-4 was reisolated from symptomatic tissues and identified as previously described, confirming its pathogenicity. Damping-off or crown and root rot due to R. solani were previously detected on P. edulis in Brazil, Africa, India, Oceania, and Australia (2). To our knowledge, this is the first report of R. solani causing crown and root rot on P. mollissima. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) J. L. Bezerra and M. L. Oliveira. Fitopathol. Brasil. 9:273, 1984. (3) D. E. Carling. Page 37 in: Grouping in Rhizoctonia solani by Hyphal Anastomosis Reactions. Kluwer Academic Publishers, the Netherlands, 1996. (4) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

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Population dynamics of Myrothecium roridum Tode ex. Fr. and Rhizoctonia solani Kühn in commercial coffee nurseries

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v80i3.4365 ◽

1969 ◽

Vol 80 (3) ◽

pp. 145-156

Author(s):

Fabio Bautista-Pérez ◽

Rocío del P. Rodríguez

Keyword(s):

Population Dynamics ◽

Rhizoctonia Solani ◽

Disease Incidence ◽

Primary Source ◽

Primary Role ◽

Canker Disease ◽

Coffee Pulp ◽

Myrothecium Roridum ◽

Highly Correlated ◽

Stem Cankers

Sources of inoculum and population dynamics of Myrothecium roridum and Rhizoctonia solani, causal organisms of cankers and root rot in nursery coffee plants, were studied. Six commercial nurseries were selected on the basis of presence of disease, and samples were taken every eight weeks. Correlated with disease incidence were variables such as density of propagules for both pathogens ¡n soil of diseased plants, apparently healthy plants, and chlorotic plants; in fumigated and non fumigated soil; in organic matter used for the mixture; and in sand from the seedbed. Density of propagules of M. roridum was estimated on the basis of the colony-forming units (CFU); that of R. solani, on the basis of percentage of colonized sugarbeet seeds. Neither of the pathogens was detected in the coffee pulp. Higher density of propagules was obtained in the soil at 5-cm depth.The highly correlated density of M. roridum with disease incidence per season and nursery indicated its primary role in coffee stem cankers in the nurseries. The presence of M. roridum in the sand of asymptomatic seedlings and the high correlation with its density in soil of plants in the nursery suggests that seedlings are the primary source of inoculum for canker disease of plants in the nursery.

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Management of root rot and stem canker of coffee with fungicides

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v85i3-4.3072 ◽

1969 ◽

Vol 85 (3-4) ◽

pp. 187-195

Author(s):

Wanda Mercado ◽

Rocío del P. Rodríguez

Keyword(s):

Rhizoctonia Solani ◽

Root Rot ◽

Stem Canker ◽

Copper Hydroxide ◽

Gliocladium Virens ◽

Myrothecium Roridum ◽

Seedling Protection ◽

Greenhouse Tests

Greenhouse tests were conducted to evaluate the effect of iprodione (Rovral®), fosetyl-AI (Alliete®), triadimephon (Bayleton 50DF®), SoilGard® (Gliocladium virens), pentachloronitrobenzene (PCNB) (Terraclor®), copper hydroxide (Champion®), benomyl (Benlate 50WP®) and "Garlic Barrier" in the population of Rhizoctonia solani and Myrothecium roridum. The most promising fungicides were evaluated at different dosages (X/2, X and 2X) to determine seedling protection and toxicity. Pentachloronitrobenzene, benomyl and iprodione were the most effective in reducing the population of ft solant in the inoculated soil with 93, 75 and 70% of inhibition, respectively. A phytotoxicity effect was observed in coffee seedlings treated with the double dosage of PCNB. The effect of fungicides was minimal in the reduction of the propagules of M. roridum when compared to the control although benomyl and triadimephon protected the seedlings against this pathogen.

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Influence of internal seedborne Fusarium semitectum on cotton seedlings

Fitopatologia Brasileira ◽

10.1590/s0100-41582005000200014 ◽

2005 ◽

Vol 30 (2) ◽

pp. 183-186 ◽

Cited By ~ 6

Author(s):

Maria L. N. Costa ◽

Onkar D. Dhingra ◽

Janaina L. da Silva

Keyword(s):

Rhizoctonia Solani ◽

Seed Coat ◽

Root Rot ◽

Seedling Emergence ◽

Threshold Level ◽

Seedling Mortality ◽

Disease Symptoms ◽

Collar Rot ◽

Fusarium Semitectum ◽

Seedborne Inoculum

Fusarium semitectum was found to be the major seed colonizing fungus in the commercial acid delinted cotton (Gossypium hirsutum) seed lots. There was no correlation, however, between its incidence and seedling emergence and disease symptoms on the emerged seedlings in autoclaved sand. Inoculation technique simulating internally seedborne nature of the fungus showed that the observed non-correlation might be related to the threshold level of seed coat colonization. The internally seedborne inoculum besides reducing seedling emergence, incited an array of symptoms on the emerged seedlings, which ranged from negative geotropism, leaf tearing, collar rot leading to dry root rot and seedling mortality. The dry root rot continued to develop on the plants surviving the seedling phase. The collar rot symptoms can be confused with those caused by Rhizoctonia solani.

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A Comparative Study of Two Components of the Poinsettia Root Rot Complex

Illinois Natural History Survey Bulletin ◽

10.21900/j.inhs.v30.161 ◽

1971 ◽

Vol 30 (1-8) ◽

pp. 419-453

Author(s):

Robert S. Perry

Keyword(s):

Environmental Factors ◽

Comparative Study ◽

Rhizoctonia Solani ◽

Root Rot ◽

Pythium Ultimum ◽

Thielaviopsis Basicola ◽

Disease Symptoms ◽

Factors Affecting

THE MOST IMPORTANT pathological problem encountered by commercial growers of poinsettias ( Euphorbia piilcheirima Willd.) is caused by a complex of fungi composed of Thielaviopsis basicola (Berk. & Br.) Ferr., Rhizoctonia solani Kuhn, and Pythium ultimum Trow. Collectively these three organisms cause a condition referred to as the poinsettia root rot complex. Since more research has been conducted on P. ultimum and R. solani than on T. basicola, the present research was originally designed to investigate some of the environmental factors affecting the growth of Thielaviopsis and the development of the root rot caused by it. However, another fungus, Chalaropsis thielavioides Peyronel, frequently was obtained in isolations from diseased greenhouse poinsettias. Since C. thielavioides had not been reported as being a part of the poinsettia root rot complex, the author decided to investigate its importance as a pathogen on poinsettias. Numerous similarities between C. thielavioides and T. basicola were evident. The object of this work was to compare the two fungi. Prior to undertaking such a study, the pathogenicity of Chalaropsis on poinsettias had to be established. A comparison of Chalaropsis and two isolates of Thielaviopsis was made to determine the effects of environment on the growth of the fungi and the ability of the two fungi to produce disease symptoms on poinsettias.

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Root Crown Response to Fungal Root Rot in Phaseolus vulgaris Middle American × Andean Lines

Plant Disease ◽

10.1094/pdis-05-20-0956-re ◽

2020 ◽

Vol 104 (12) ◽

pp. 3135-3142

Author(s):

Miranda J. Haus ◽

Weijia Wang ◽

Janette L. Jacobs ◽

Hannah Peplinski ◽

Martin I. Chilvers ◽

...

Keyword(s):

Phaseolus Vulgaris ◽

Root Rot ◽

Root Architecture ◽

Adventitious Roots ◽

Root Traits ◽

Root Systems ◽

Early Growth ◽

Growth Stages ◽

Root Number ◽

Disease Symptoms

Fusarium root rot (FRR) is a global limiter of dry bean (Phaseolus vulgaris L.) production. In common bean and other legumes, resistance to FRR is related to both root development and root architecture, providing a breeding strategy for FRR resistance. Here, we describe the relationships between root traits and FRR disease symptoms. Using “shovelomics” techniques, a subset of recombinant inbred lines was phenotyped for root architecture traits and disease symptoms across three Michigan fields, including one field with artificially increased Fusarium brasiliense disease pressure. At the early growth stages, stem diameter, basal root number, and distribution of hypocotyl-borne adventitious roots were all significantly related to FRR disease scores. These results demonstrate that root architecture is a component of resistance to FRR in the field at early growth stages (first expanded trifoliate) complementing previous studies that evaluated root traits at later developmental stages (flowering, pod fill, etc.). Correlation matrices of root traits indicate that resistant and susceptible lines have statistically different root systems and show that basal root number is a key feature in resistant root systems while adventitious root distribution is an important feature in susceptible root systems. Based on the results of this study, selection for increased basal root number, increased adventitious root number, and even distribution of adventitious roots in early growth stages (first expanded trifoliate) would positively impact resistance to FRR.

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Episodic Abiotic Stress as a Potential Contributing Factor to Onset and Severity of Disease Caused by Phytophthora ramorum in Rhododendron and Viburnum

Plant Disease ◽

10.1094/pdis-93-9-0912 ◽

2009 ◽

Vol 93 (9) ◽

pp. 912-918 ◽

Cited By ~ 10

Author(s):

Tatiana V. Roubtsova ◽

Richard M. Bostock

Keyword(s):

Abiotic Stress ◽

Phytophthora Ramorum ◽

Symptom Development ◽

Root Infection ◽

Disease Symptoms ◽

Foliar Blight ◽

Disease Predisposition ◽

Stem Lesions ◽

Faster Development ◽

Stem Cankers

Phytophthora ramorum attacks many forest and nursery species, primarily causing trunk or stem cankers, foliar blight, and dieback, and in some species root infection has been demonstrated. However, the abiotic and edaphic factors that influence infection and disease development are unresolved. Root infection by P. ramorum and the potential for mild abiotic stress in disease predisposition was examined with Rhododendron hybrid Cunningham's White and Viburnum tinus cv. Spring Bouquet. To impose water stress in a uniform and synchronous manner, osmotic stress induced with 0.2 M NaCl was selected. Roots were exposed to NaCl for 16 to 24 h in modified hydroponic culture or standard potting soil, removed from the NaCl, and then inoculated with zoospores. In the hydroponic regime, disease symptoms developed in Rhododendron and V. tinus plants within 1 week after inoculation of salt-stressed roots, whereas symptom development was delayed in nonstressed, inoculated plants. Microscopic examination of roots from both species revealed that their apices were covered with sporangia of P. ramorum. On potted Rhododendron plants inoculated by applying zoospores directly to the soil, stem lesions developed rapidly in salt-stressed plants, with death of the plant occurring within 4 weeks after inoculation. Nonstressed plants survived for 6 to 8 weeks before succumbing to disease, and symptom development in these plants was delayed by 1 to 2 weeks relative to the inoculated, salt-stressed plants. A postinfection episode of salt stress to inoculated roots in the hydroponic regime resulted in significantly faster development of stem lesions in Rhododendron relative to nonstressed, inoculated plants.

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Myrothecium roridum. [Descriptions of Fungi and Bacteria].

IMI Descriptions of Fungi and Bacteria ◽

10.1079/dfb/20056400253 ◽

1970 ◽

Author(s):

M. Fitton

Keyword(s):

Geographical Distribution ◽

Trifolium Pratense ◽

Tomato Fruit ◽

Solanum Melongena ◽

Damping Off ◽

Hibiscus Esculentus ◽

Myrothecium Roridum ◽

Stem Lesions ◽

Stem Cankers ◽

Soil Level

Abstract A description is provided for Myrothecium roridum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Plurivorous. On Antirrhinum, Coffea, Cucurbitaceae, Cyamopsis psoraloides, Gardenia, Gloxinia, Gossypium, Hibiscus esculentus, Hypocyrta, Lycopersicon esculentum, Molucella, Sesamum indicum, Solanum melongena, Trifolium pratense, Vigna unguiculata, Vinca, Viola. DISEASE: Commonly causing necrotic lesions or shot holes on leaves but can also occur on petioles, stems and fruit. Small, sometimes water-soaked, lesions increase to about 2.5 cm diam. ; they may be zonate and coalesce, defoliating the plant. On many hosts infection is most serious under nursery or glasshouse contitions. Infection leads to stem lesions, dieback of the crown and decay at soil level; this may resemble typical damping-off symptoms. Stem cankers have been reported on cotton and sunken lesions on the fruit of cantaloupe. On tomato fruit a firm, black rot develops, with a sharply delimited border between healthy and diseased tissue; the rotted part can be removed readily in one piece (25: 345; 35: 19; 36: 528; 41: 199; 44: 1586, 3367; 49: 503). GEOGRAPHICAL DISTRIBUTION: Widespread (CMI Map 458, ed. 1, 1969); possibly more serious in warmer regions. TRANSMISSION: Probably a common soil saprophyte, with the capacity to become actively parasitic under conditions not yet clearly definable. Infection of cotton bolls and carpel walls is reported (43, 3382b). Seed of C. psoraloides when inoculated gave only 16% germination compared with 93% for the uninoculated seed.

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First Report of Crown and Root Rot Caused by Rhizoctonia solani AG-4 on Coprosma repens and C. lucida in Italy

Plant Disease ◽

10.1094/pdis-93-9-0972b ◽

2009 ◽

Vol 93 (9) ◽

pp. 972-972 ◽

Cited By ~ 2

Author(s):

G. Polizzi ◽

D. Aiello ◽

I. Castello ◽

A. Vitale

Keyword(s):

Rhizoctonia Solani ◽

Root Rot ◽

Disease Incidence ◽

Morphological Characteristics ◽

Fluorescent Light ◽

Centraalbureau Voor ◽

First Report ◽

Crown And Root Rot ◽

Stem Lesions ◽

Safranin O

Coprosma (J.R. Forster & G. Forster), a genus containing approximately 90 species, occurs principally in New Zealand, Hawaii, Australia, New Guinea, and islands of the Pacific. In Italy, some of these species, including many variegated varieties and hybrids, are grown as ornamental evergreen shrubs or small trees. In June 2008, a crown and root rot was observed in a stock of approximately 12,000 potted 3-year-old plants of Coprosma repens cv. Yvonne and C. lucida in a nursery in eastern Sicily. Disease incidence was approximately 30%. Disease symptoms consisted of water-soaked lesions at the crown of the trunk and a root rot. Successively, older stem lesions turned orange to brown. As a consequence, leaves initially became chlorotic, gradually became necrotic, and death of the plant followed. A fungus with mycelial and morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from crown and root lesions when plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 μg/ml. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Mycelium was branched at right angles with a septum near the branch and a slight constriction at the branch base. Hyphal cells removed from cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400. Anastomosis groups were determined by pairing isolates on 2% water agar in petri plates (3). Pairings were made with tester strains of AG-1 IA, AG-2-2-1, AG-2-2IIIB, AG-2-2IV, AG-3, AG-4, AG-5, AG-6, and AG-11. Anastomosis was observed only with tester isolates of AG-4, giving C2 and C3 reactions (2). Two representative isolates obtained from symptomatic tissues of C. lucida and C. repens cv. Yvonne were deposited at the Fungal Biodiversity Centre, Centraalbureau voor Schimmelcultures (DISTEF CL1 = CBS-124593 and DISTEF CR1 = CBS-124594, respectively). Pathogenicity tests were performed on container-grown, healthy, 3-month-old cuttings. Ten plants of C. lucida and ten plants of C. repens cv. Yvonne were inoculated near the base of the stem with five 1-cm2 PDA plugs from 5-day-old mycelial cultures. The same number of plants served as uninoculated controls. Plants were maintained at 25°C and 95% relative humidity on a 12-h fluorescent light/dark regimen. Symptoms identical to ones observed in the nursery appeared 5 days after inoculation and all plants died within 15 days. No disease was observed on control plants. A fungus identical in culture morphology to R. solani AG-4 was consistently reisolated from symptomatic tissues, confirming its pathogenicity. To our knowledge, this is the first report of R. solani causing crown and root rot on the genus Coprosma. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. Carling. Page 37 in: Grouping in Rhizoctonia solani by Hyphal Anastomosis Reactions. Kluwer Academic Publishers, the Netherlands, 1996. (3) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

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