scholarly journals Response of Cover Crops to Phytopythium vexans, Phytophthora nicotianae, and Rhizoctonia solani, Major Soilborne Pathogens of Woody Ornamentals

Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 742
Author(s):  
Milan Panth ◽  
Anthony Witcher ◽  
Fulya Baysal-Gurel
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Cover Crops ◽  
Production System ◽  
Root Rot ◽  
Phytophthora Nicotianae ◽  
Soilborne Pathogens ◽  
Damping Off ◽  
Root Rot Disease ◽  
Rot Disease

Management of plant diseases is a subject of concern for researchers as well as growers. Different management practices are being developed and used to combat the rising number of plant pathogens, which threaten nursery crop production. Use of cover crops for sustainable management of soilborne diseases is being explored as an alternative strategy to the chemicals. However, the potential threat of these cover crops acting as a secondary host of these devastating soilborne pathogens has not been described. We studied the response of the major cover crops being used by woody ornamental growers in the Southeastern United States to Phytopythium vexans, Phytophthora nicotianae, and Rhizoctonia solani in greenhouse conditions to identify the effective cover crops that can be used in a nursery field production system. Data related to post-emergence damping-off and plant growth parameters (plant height increase and fresh weight) were recorded. Similarly, cover crop roots were assessed for root rot disease severity using a scale of 0–100% roots affected. Among the tested cover crops, the grass cover crops triticale (×Triticosecale Wittm. ex A. Camus.), annual ryegrass (Lolium multiflorum L.), Japanese millet (Echinochloa esculenta (A. Braun) H. Scholz), and the legumes Austrian winter pea (Pisum sativum var. arvense (L.) Poir) and cowpea ‘Iron and Clay’ (Vigna unguiculata (L.) Walp.), showed lower root rot disease severity and post-emergence damping-off in the soil inoculated with P. nicotianae, R. solani, or P. vexans compared to the other crops. Since these cover crops can act as non-host crops and benefit the main crop in one way or another, they can be used in the production system. Further research is recommended to evaluate their performance in a natural field setting.

scholarly journals Bacillus megaterium-Mediated Synthesis of Selenium Nanoparticles and Their Antifungal Activity against Rhizoctonia solani in Faba Bean Plants

2021 ◽  
Vol 7 (3) ◽  
pp. 195
Author(s):  
Amr H. Hashem ◽  
Amer M. Abdelaziz ◽  
Ahmed A. Askar ◽  
Hossam M. Fouda ◽  
Ahmed M. A. Khalil ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Vicia Faba ◽  
Root Rot ◽  
Antifungal Agents ◽  
Damping Off ◽  
Growth Promoters ◽  
Root Rot Disease ◽  
Rot Disease

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.

scholarly journals Role of Bradyrhizobium japonicum and Trichoderma spp. in the control of root rot disease of soybean

2014 ◽  
Vol 30 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Syed Ehteshamul-Haque ◽  
Abdul Ghaffar
Keyword(s):  
Grain Yield ◽  
Rhizoctonia Solani ◽  
Trichoderma Harzianum ◽  
Root Rot ◽  
Bradyrhizobium Japonicum ◽  
Seed Treatment ◽  
Trichoderma Spp ◽  
Root Rot Disease ◽  
Rot Disease

Seed treatment of soybean with <i>Bndyrhizobium japonicum, Trichoderma harzianum, T. viride, T. hamatum, T. koningii</i> and <i>T. pseudokoningii</i> significantly controlled the infection of 30-day-old seedlingsby <i>Maerophomina phaseolina, Rhizoctonia solani</i> and <i>Fusarium</i> spp. In 60-day-old plants <i>Trichoderma</i> spp.. and <i>B. japonicum</i> inhibited the grouth of <i>R. solani</i> and <i>Fusarium</i> spp., whereas the use of <i>B. japonicum</i> (TAL-102) with <i>T. harzianum. T. viride, T. koningii</i> and <i>T. pseudokoningii</i> controlled the infection by <i>M. phaseolina. Greater grain yield was recorded when B. <i>japonium</i> (TAI-102) was used with <i>T. hamatum</i>.

scholarly journals A nondestructive method to assess rot root severity of Lactuca sativa L

2013 ◽  
Vol 66 ◽  
pp. 375-375
Author(s):  
P. Suvarnaphaet ◽  
V. Tanmala ◽  
M. Kanjanamaneesathian
Keyword(s):  
Image Analysis ◽  
Disease Severity ◽  
Digital Image ◽  
Lactuca Sativa ◽  
Root Rot ◽  
Digital Image Analysis ◽  
Disease Assessment ◽  
Root Rot Disease ◽  
Diseased Root ◽  
Rot Disease

Root rot disease caused by aquatic fungi such as Aphanomyces sp and Pythium sp is prevalent in Lactuca sativa grown in a dynamic root floating technique (DRFT) hydroponic system in Phetchaburi College of Agriculture and Technology Thailand Roots of this plant have been severely infected with these fungi and plant growth has been affected resulting in a decline of yield over time Symptoms of root rot are initially characterised by tissue discoloration in some parts of the root followed by a loss of tissue integrity of the whole root In the DRFT system root rot symptoms of L sativa range from severe (complete) root rot to a healthylooking root (no symptoms)This study investigated the potential for using digital images as an objective tool for assessing disease severity with the aim of the tool being applied by assessors with no previous experience in disease assessment Lactuca sativa that had been grown in DRFT for 30 days and had various degrees of root rot symptoms were selected for the study Visual evaluation of the diseased root indicated that there were six levels of disease severity with root colour ranging from white (healthy looking) to completely black (severe root rot)When the diseased root samples were subjected to digital image analysis between the black and white extremes there was one shade of grey and three shades of brown The images of these six levels of severity were analysed using Hunter L a and b values It was found that the six levels of root rot severity could be distinguished based upon the L parameters The value of Lightness (Hunter L) which is transformed from RGB digital image (using a color calculator in http//wwweasyrgbcom) decreased exponentially (from severity level 1 to 6) with a constant value at 048 This indicates that digital image analysis using this simple tool can be utilised to objectively assess root rot disease in L sativa Once this technology is thoroughly studied developed and validated for lettuce growing in the DRFT system there is potential for it to be a useful tool to assist lettuce growers in making a decision to implement control measures

scholarly journals Impact of Cover Crop Usage on Soilborne Diseases in Field Nursery Production

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 753 ◽  
Author(s):  
Sujan Dawadi ◽  
Fulya Baysal-Gurel ◽  
Karla M. Addesso ◽  
Jason B. Oliver ◽  
Terri Simmons
Keyword(s):  
Disease Severity ◽  
Cover Crops ◽  
Cover Crop ◽  
Acer Rubrum ◽  
Soilborne Pathogens ◽  
Red Maple ◽  
Damping Off ◽  
Field Nursery ◽  
Nursery Production ◽  
The Impact

Soilborne pathogens are a significant economic problem for nursery production in the Southeastern United States. The goal of this study was to determine the impact of cover crops on soilborne disease suppressiveness in such systems. Soils from red maple (Acer rubrum L.) plantation fields grown with and without cover crops were sampled, either while the cover crops were growing (pre-disked) or post-season, following cover crop incorporation into the soil (post-disked). Greenhouse bioassays were conducted using red maple seeds on inoculated (with Rhizoctonia solani (J.G. Kühn) or Phytophthora nicotianae (Breda de Haan)) and non-inoculated field soils. The damping-off, root rot disease severity, percent recovery of Rhizoctonia and Phytophthora, and pseudomonad population were examined during the two years of the experiment. Results showed that cover crop incorporation was beneficial for inducing disease supressiveness characteristics of soil. Cover crop incorporation into the soil significantly or numerically reduced disease severity and pathogen recovery in infested soil compared to the bare soil treatment. Cover crop incorporation was found to be partially associated with the reduction of seedling damping-off. The pseudomonad microbial population was greater when cover crop was present, and is thought to be antagonist to soilborne pathogens. Therefore, cover crops can be integrated in field nursery production systems to suppress soilborne pathogens.

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

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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