Environmental Factors on the Development of Root Rot on Ginseng Caused by Cylindrocarpon destructans

The fungus Cylindrocarpon destructans (Zins) Scholten is the cause of root rot (disappearing root rot) in many ginseng production areas in Canada. A total of 80 isolates of C. destructans were recovered from diseased roots in a survey of ginseng gardens in British Columbia from 2002-2004. Among these isolates, 49% were classified as highly virulent (causing lesions on unwounded mature roots) and 51% were weakly virulent (causing lesions only on previously wounded roots). Pectinase and polyphenoloxidase enzymes were produced in vitro by C. destructans isolates when they were grown on pectin and phenol as a substrate, respectively. However, highly virulent isolates produced significantly (P < 0.001) higher enzyme levels compared with weakly virulent isolates. Histopathological studies of ginseng roots inoculated with a highly virulent isolate revealed direct hyphal penetration through the epidermis, followed by intracellular hyphal growth in the cortex. Subsequent cell disintegration and accumulation of phenolic compounds was observed. Radial growth of highly and weakly virulent isolates on potato dextrose agar was highest at 18 and 21°C, respectively and there was no growth at 35°C. Mycelial mass production was significantly (P ≤ 0.01) lower at pH 7.0 compared with pH 5.0. To study the effects of pH (5.0 and 7.0) and wounding on disease development, ginseng roots were grown hydroponically in Hoagland's solution. Lesions were significantly larger (P < 0.001) at pH 5.0 compared with pH 7.0 and wounding enhanced disease by a highly virulent isolate at both pHs. In artificially infested soil, 2-year-old ginseng roots were most susceptible to Cylindrocarpon root rot among all root ages tested (1 to 4 years) when evaluated using a combined scale of disease incidence and severity. Root rot severity was significantly (P < 0.002) enhanced by increasing the inoculum density from 3.45 × 102 CFU/g of soil to 1.86 × 103 CFU/g of soil. Disease severity was higher at 20°C compared with 15 and 25°C and at -0.02 MPa soil moisture compared with -0.005 and -0.001 MPa. A significant interaction between soil moisture and temperature was observed for root rot severity.

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Effect of Soil Inoculum Density and Temperature on the Incidence of Cucumber Black Root Rot

Plant Disease ◽

10.1094/pdis-12-14-1287-re ◽

2016 ◽

Vol 100 (1) ◽

pp. 125-130 ◽

Cited By ~ 1

Author(s):

Kuniaki Shishido ◽

Hiroyuki Murakami ◽

Daiki Kanda ◽

Shin-ichi Fuji ◽

Takeshi Toda ◽

...

Keyword(s):

Environmental Factors ◽

Soil Temperature ◽

Root Rot ◽

Strongly Correlated ◽

Black Root Rot ◽

Soil P ◽

Control Techniques ◽

Soil Inoculum ◽

Phomopsis Sclerotioides ◽

Soil Disinfection

The effects of the density of Phomopsis sclerotioides in soil and other environmental factors on black root rot of cucumber were investigated. Cucumber plants were grown in soil containing P. sclerotioides at 1, 10, 100, and 1000 CFU/g. Wilt incidence from 3 to 7 weeks after transplanting was strongly correlated with P. sclerotioides density in soil (P < 0.05). Root rot of squash rootstock occurred in soil with very low inoculum densities (0.1 CFU/g), and was strongly related to P. sclerotioides density (Y = −0.3x + 1.2, R2 = 0.743, P < 0.05) at 8 weeks after transplanting. Cucumber plants showed wilt symptoms in soil containing 1 CFU/g. Wilt symptoms in cucumber plants occurred 4 to 7 days earlier in soil at 22°C than in soil at 27 or 17°C. Root rot development could be predicted from the density of P. sclerotioides in soil and soil temperature. However, further studies on the effects of other environmental factors are required to test the linear model in commercial fields. This information is essential for determining the threshold pathogen density at which most control techniques, particularly those other than soil disinfection, will be effective.

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Biocontrol Efficacies of Bacillus Species Against Cylindrocarpon destructans Causing Ginseng Root Rot

The Plant Pathology Journal ◽

10.5423/ppj.2011.27.4.333 ◽

2011 ◽

Vol 27 (4) ◽

pp. 333-341 ◽

Cited By ~ 23

Author(s):

Ye-Lim Jang ◽

Sang-Gyu Kim ◽

Young-Ho Kim

Keyword(s):

Root Rot ◽

Ginseng Root ◽

Bacillus Species ◽

Cylindrocarpon Destructans

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Influence of Temperature on the Pathogenesis and Gene Expression of Rhizoctonia solani Causing Web Blight/Wet Root Rot Disease in Mungbean

Legume Research - An International Journal ◽

10.18805/lr-4342 ◽

2020 ◽

Author(s):

Bishnu Maya Bashyal ◽

Bhupendra Singh Kharayat ◽

Pooja Parmar ◽

Ashish Kumar Gupta ◽

S. C. Dubey ◽

...

Keyword(s):

Environmental Factors ◽

Rhizoctonia Solani ◽

Root Rot ◽

Time Interval ◽

Post Inoculation ◽

Root Rot Disease ◽

Different Temperatures ◽

Rot Disease ◽

Blight Disease ◽

Web Blight

Background: Mungbean (Vigna radiata L. Wilzeck) is one of the most important pulse crops and grown in almost all parts of the India. Web blight/wet root rot disease of mungbean is caused by Rhizoctonia solani Kühn. Crop environmental factors plays a vital role in the development of web blight disease caused by R. solani. An understanding of the role of environmental factors on the infection and survival of the pathogen is necessary to develop disease management practices. Methods: The effect of different temperatures (4oC, 20oC, 25oC, 30oC and 35oC) on mycelial growth of seven different R. solani isolates belonging to different anastomosis group were evaluated under in vitro conditions. Effect of different temperatures on the development of root rot/web blight disease of mungbean was also evaluated under phytotron conditions at various temperatures with constant relative humidity (85%) and illumination (alternate dark and light period of 12 h). Effect of temperatures on the expression of selected pathogenicity related genes was evaluated through real time PCR. Result: Maximum radial growth in R. solani isolates was observed at 25 and 30oC after 48 hrs of incubation. Maximum disease incidence was observed with R. solani isolate RUPU-18 (73.11%) followed by R-17 (68.75%), RDLM-1 (63.45%) at 25oC on mungbean genotype Pusa Vishal. Expression of genes like ABC transporter was observed only at 35oC, while other genes like 1, 3 glucan hydrolase expressed maximum at 25oC after 24, 48 and 72 hrs post inoculation. Present study suggested that the expression of pathogenicity related genes in mungbean-R. solani system is dependent on the temperature and time interval post pathogen inoculation.

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Antagonistic Evaluation of Chromobacterium sp. JH7 for Biological Control of Ginseng Root Rot Caused by Cylindrocarpon destructans

Mycobiology ◽

10.5941/myco.2017.45.4.370 ◽

2017 ◽

Vol 45 (4) ◽

pp. 370-378 ◽

Cited By ~ 6

Author(s):

Joon-Hee Han ◽

Gi-Chang Park ◽

Kyoung Su Kim

Keyword(s):

Biological Control ◽

Root Rot ◽

Ginseng Root ◽

Cylindrocarpon Destructans

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Fungal biocontrol of root diseases: endomycorrhizal suppression of cylindrocarpon root rot

Canadian Journal of Botany ◽

10.1139/b95-230 ◽

1995 ◽

Vol 73 (S1) ◽

pp. 89-95 ◽

Cited By ~ 13

Author(s):

James A. Traquair

Keyword(s):

Root Rot ◽

Mycorrhizal Fungi ◽

Fungal Pathogens ◽

Cylindrocarpon Destructans ◽

Root Diseases ◽

Complex Interactions ◽

New Concepts ◽

Technical Innovations ◽

Inoculum Preparation ◽

Peach Rootstocks

Many reviews in the past decade outline the need to understand the complex interactions between fungal pathogens of roots, mycorrhizal fungi, mycorrhizosphere associates, and various climatic and edaphic factors to develop stable mycorrhizal biocontrol strategies. Cylindrocarpon root rot caused by Cylindrocarpon destructans is a good example of a replant disorder that is amenable to this type of control in nurseries and new or renovated orchard sites. Cylindrocarpon root rot was reduced by endomycorrhizal colonization of potted peach rootstocks with Glomus aggregatum under controlled environment conditions using Turface or natural, untreated orchard soils. Several mechanisms of suppression are discussed including tolerance to the pathogen through increased host vigor and reduced exudation, competition for space and nutrients, and induced host resistance. Technical innovations and new concepts of fungal community ecology are improving the odds of developing effective biocontrols with mycorrhizae. Exploitation of natural and integrated disease management using multiple mechanisms of pathogen inhibition may offset the difficulties in inoculum preparation. Key words: Cylindrocarpon destructans, antagonism, competition, rhizosphere, mycorrhizosphere.

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