Journal articles on the topic 'Fungal root pathogens'
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1
Castellanos-Morales, V., R. Cárdenas-Navarro, J. M. García-Garrido, A. Illana, J. A. Ocampo, S. Steinkellner, and H. Vierheilig. " Bioprotection against Gaeumannomyces graminis in barley a comparison between arbuscular mycorrhizal fungi." Plant, Soil and Environment 58, No. 6 (June 18, 2012): 256–61. http://dx.doi.org/10.17221/622/2011-pse.
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Gaeumannomyces graminis var. tritici causes take-all disease, the most important root disease of cereal plants. Cereal plants are able to form a symbiotic association with soil-borne arbuscular mycorrhizal fungi which can provide bioprotection against soil-borne fungal pathogens. However, the bioprotective effect of arbuscular mycorrhizal fungi against soil-borne fungal pathogens might vary. In the present study we tested the systemic bioprotective effect of the arbuscular mycorrhizal fungi Glomus mosseae, Glomus intraradices and Gigaspora rosea against the soil-borne fungal pathogen Gaeumannomyces graminis var. tritici in a barley split-root system. Glomus intraradices, Glomus mosseae and Gigaspora rosea colonized the split-root system of barley plants at different levels; however, all arbuscular mycorrhizal fungi clearly reduced the level of root lesions due to the pathogen Gaeumannomyces graminis. Our data indicate that some arbuscular mycorrhizal fungi need high root colonization rates to protect plants against fungal pathogens, whereas others act already at low root colonization rates.
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Loit, Kaire, Liina Soonvald, Alar Astover, Eve Runno-Paurson, Maarja Öpik, and Leho Tedersoo. "Temporal and Cultivar-Specific Effects on Potato Root and Soil Fungal Diversity." Agronomy 10, no. 10 (October 9, 2020): 1535. http://dx.doi.org/10.3390/agronomy10101535.
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The soil fungal community plays an important role in determining plant growth and health. In this study, we investigated the fungal diversity and community composition in the roots and soil of 21 potato (Solanum tuberosum L.) cultivars using high-throughput sequencing at three different time points across the growing season. In soil and roots, the fungal richness and relative abundance of pathogens and saprotrophs were mainly affected by sampling time. While sampling time affected fungal composition in soil, root fungal communities were also significantly affected by cultivar. The cultivar had the strongest effect on diversity of pathogens and abundance of particular pathogen species. Our results demonstrate changes in soil and root fungal communities of potato over the growing season, as well as highlighting the importance of potato cultivar on root fungal communities and abundance of pathogens.
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Traquair, James A. "Fungal biocontrol of root diseases: endomycorrhizal suppression of cylindrocarpon root rot." Canadian Journal of Botany 73, S1 (December 31, 1995): 89–95. http://dx.doi.org/10.1139/b95-230.
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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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Delavaux, Camille S., Josh L. Schemanski, Geoffrey L. House, Alice G. Tipton, Benjamin Sikes, and James D. Bever. "Root pathogen diversity and composition varies with climate in undisturbed grasslands, but less so in anthropogenically disturbed grasslands." ISME Journal 15, no. 1 (September 21, 2020): 304–17. http://dx.doi.org/10.1038/s41396-020-00783-z.
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AbstractSoil-borne pathogens structure plant communities, shaping their diversity, and through these effects may mediate plant responses to climate change and disturbance. Little is known, however, about the environmental determinants of plant pathogen communities. Therefore, we explored the impact of climate gradients and anthropogenic disturbance on root-associated pathogens in grasslands. We examined the community structure of two pathogenic groups—fungal pathogens and oomycetes—in undisturbed and anthropogenically disturbed grasslands across a natural precipitation and temperature gradient in the Midwestern USA. In undisturbed grasslands, precipitation and temperature gradients were important predictors of pathogen community richness and composition. Oomycete richness increased with precipitation, while fungal pathogen richness depended on an interaction of precipitation and temperature, with precipitation increasing richness most with higher temperatures. Disturbance altered plant pathogen composition and precipitation and temperature had a reduced effect on pathogen richness and composition in disturbed grasslands. Because pathogens can mediate plant community diversity and structure, the sensitivity of pathogens to disturbance and climate suggests that degradation of the pathogen community may mediate loss, or limit restoration of, native plant diversity in disturbed grasslands, and may modify plant community response to climate change.
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Gao, Ying, Ethan Swiggart, Kaela Wolkiewicz, Prabha Liyanapathiranage, Fulya Baysal-Gurel, Farhat A. Avin, Eleanor F. P. Lopez, Rebecca T. Jordan, Joshua Kellogg, and Eric P. Burkhart. "Goldenseal (Hydrastis canadensis L.) Extracts Inhibit the Growth of Fungal Isolates Associated with American Ginseng (Panax quinquefolius L.)." Molecules 29, no. 3 (January 23, 2024): 556. http://dx.doi.org/10.3390/molecules29030556.
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American ginseng, a highly valuable crop in North America, is susceptible to various diseases caused by fungal pathogens, including Alternaria spp., Fusarium spp., and Pestalotiopsis spp. The development of alternative control strategies that use botanicals to control fungal pathogens in American ginseng is desired as it provides multiple benefits. In this study, we isolated and identified three fungal isolates, Alternaria panax, Fusarium sporotrichioides, and Pestalotiopsis nanjingensis, from diseased American ginseng plants. Ethanolic and aqueous extracts from the roots and leaves of goldenseal were prepared, and the major alkaloid constituents were assessed via liquid chromatography–mass spectrometry (LC–MS). Next, the antifungal effects of goldenseal extracts were tested against these three fungal pathogens. Goldenseal root ethanolic extracts exhibited the most potent inhibition against fungal growth, while goldenseal root aqueous extracts and leaf ethanolic extracts showed only moderate inhibition. At 2% (m/v) concentration, goldenseal root ethanolic extracts showed an inhibition rate of 86.0%, 94.9%, and 39.1% against A. panax, F. sporotrichioides, and P. nanjingensis, respectively. The effect of goldenseal root ethanolic extracts on the mycelial morphology of fungal isolates was studied via scanning electron microscopy (SEM). The mycelia of the pathogens treated with the goldenseal root ethanolic extract displayed considerable morphological alterations. This study suggests that goldenseal extracts have the potential to be used as a botanical fungicide to control plant fungal diseases caused by A. panax, F. sporotrichioides, or P. nanjingensis.
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Wang, Chengxian, Jianfeng Liu, Changmei Wang, Xingling Zhao, Kai Wu, Bin Yang, Fang Yin, and Wudi Zhang. "Biogas slurry application alters soil properties, reshapes the soil microbial community, and alleviates root rot of Panax notoginseng." PeerJ 10 (July 26, 2022): e13770. http://dx.doi.org/10.7717/peerj.13770.
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Background Panax notoginseng is an important herbal medicine in China, where this crop is cultivated by replanting of seedlings. Root rot disease threatens the sustainability of P. notoginseng cultivation. Water flooding (WF) is widely used to control numerous soilborne diseases, and biogas slurry shows positive effects on the soil physiochemical properties and microbial community structure and has the potential to suppress soilborne pathogens. Hence, biogas slurry flooding (BSF) may be an effective approach for alleviating root rot disease of P. notoginseng; however, the underlying mechanism needs to be elucidated. Methods In this study, we conducted a microcosm experiment to determine if BSF can reduce the abundance of pathogens in soil and, alleviate root rot of P. notoginseng. Microcosms, containing soil collected from a patch of P. notoginseng showing symptoms of root rot disease, were subjected to WF or BSF at two concentrations for two durations (15 and 30 days), after which the changes in their physicochemical properties were investigated. Culturable microorganisms and the root rot ratio were also estimated. We next compared changes in the microbial community structure of soils under BSF with changes in WF and untreated soils through high-throughput sequencing of bacterial 16S rRNA (16S) and fungal internal transcribed spacer (ITS) genes amplicon. Results WF treatment did not obviously change the soil microbiota. In contrast, BSF treatment significantly altered the physicochemical properties and reshaped the bacterial and fungal communities, reduced the relative abundance of potential fungal pathogens (Fusarium, Cylindrocarpon, Alternaria, and Phoma), and suppressed culturable fungi and Fusarium. The changes in the microbial community structure corresponded to decreased root rot ratios. The mechanisms of fungal pathogen suppression by BSF involved several factors, including inducing anaerobic/conductive conditions, altering the soil physicochemical properties, enriching the anaerobic and culturable bacteria, and increasing the phylogenetic relatedness of the bacterial community. Conclusions BSF application can reshape the soil microbial community, reduce the abundance of potential pathogens, and alleviate root rot in P. notoginseng. Thus, it is a promising practice for controlling root rot disease in P. notoginseng.
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Toth, Ronald, Deborah Toth, David Starke, and David R. Smith. "Vesicular–arbuscular mycorrhizal colonization in Zea mays affected by breeding for resistance to fungal pathogens." Canadian Journal of Botany 68, no. 5 (May 1, 1990): 1039–44. http://dx.doi.org/10.1139/b90-131.
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Inbred lines of Zea mays L. (maize) selected for a range of resistances to a variety of fungal pathogens were assayed for percentage colonization by vesicular–arbuscular mycorrhizal fungi. Inbreds that were generally resistant to a number of fungal pathogens had significantly lower levels of vesicular–arbuscular mycorrhizae, matured more slowly, and had larger root systems. Disease-susceptible inbreds had significantly higher levels of mycorrhizal colonization, matured more rapidly, and had smaller root systems. It is uncertain if a general resistance to fungal pathogens or rate of root development, separately or in combination, may have influenced mycorrhizal colonization levels. Irrespective of cause, present breeding programs for disease resistance in maize do influence the plants ability to form mycorrhizae.
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Okubara, Patricia A., Amy B. Peetz, and Richard M. Sharpe. "Cereal Root Interactions with Soilborne Pathogens—From Trait to Gene and Back." Agronomy 9, no. 4 (April 13, 2019): 188. http://dx.doi.org/10.3390/agronomy9040188.
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Realizing the yield potential of crop plants in the presence of shifting pathogen populations, soil quality, rainfall, and other agro-environmental variables remains a challenge for growers and breeders worldwide. In this review, we discuss current approaches for combatting the soilborne phytopathogenic nematodes, Pratylenchus and Heterodera of wheat and barley, and Meloidogyne graminicola Golden and Birchfield, 1965 of rice. The necrotrophic fungal pathogens, Rhizoctonia solani Kühn 1858 AG-8 and Fusarium spp. of wheat and barley, also are discussed. These pathogens constitute major causes of yield loss in small-grain cereals of the Pacific Northwest, USA and throughout the world. Current topics include new sources of genetic resistance, molecular leads from whole genome sequencing and genome-wide patterns of hosts, nematode or fungal gene expression during root-pathogen interactions, host-induced gene silencing, and building a molecular toolbox of genes and regulatory sequences for deployment of resistance genes. In conclusion, improvement of wheat, barley, and rice will require multiple approaches.
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Eyles, A., C. Beadle, K. Barry, A. Francis, M. Glen, and C. Mohammed. "Management of fungal root-rot pathogens in tropicalAcacia mangiumplantations." Forest Pathology 38, no. 5 (October 2008): 332–55. http://dx.doi.org/10.1111/j.1439-0329.2008.00549.x.
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Okubara, Patricia A., and Timothy C. Paulitz. "Root Defense Responses to Fungal Pathogens: A Molecular Perspective." Plant and Soil 274, no. 1-2 (July 2005): 215–26. http://dx.doi.org/10.1007/s11104-004-7328-9.
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Richards, Andrew, Mehrbod Estaki, José Ramón Úrbez-Torres, Pat Bowen, Tom Lowery, and Miranda Hart. "Cover Crop Diversity as a Tool to Mitigate Vine Decline and Reduce Pathogens in Vineyard Soils." Diversity 12, no. 4 (March 30, 2020): 128. http://dx.doi.org/10.3390/d12040128.
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Wine grape production is an important economic asset in many nations; however, a significant proportion of vines succumb to grapevine trunk pathogens, reducing yields and causing economic losses. Cover crops, plants that are grown in addition to main crops in order to maintain and enhance soil composition, may also serve as a line of defense against these fungal pathogens by producing volatile root exudates and/or harboring suppressive microbes. We tested whether cover crop diversity reduced disease symptoms and pathogen abundance. In two greenhouse experiments, we inoculated soil with a 106 conidia suspension of Ilyonectria liriodendri, a pathogenic fungus, then conditioned soil with cover crops for several months to investigate changes in pathogen abundance and fungal communities. After removal of cover crops, Chardonnay cuttings were grown in the same soil to assess disease symptoms. When grown alone, white mustard was the only cover crop associated with reductions in necrotic root damage and abundance of Ilyonectria. The suppressive effects of white mustard largely disappeared when paired with other cover crops. In this study, plant identity was more important than diversity when controlling for fungal pathogens in vineyards. This research aligns with other literature describing the suppressive potential of white mustard in vineyards.
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Lotter, D. W., J. Granett, and A. D. Omer. "178 Differences in Grape Phylloxera-related Grapevine Root Damage in Organically and Conventionally Managed Vineyards in California." HortScience 34, no. 3 (June 1999): 472F—473. http://dx.doi.org/10.21273/hortsci.34.3.472f.
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Secondary infection of roots by fungal pathogens is a primary cause of vine damage in phylloxera-infested grapevines. In summer and fall surveys in 1997 and 1998, grapevine root samples were taken from organically managed vineyards (OMVs) and from conventionally managed vineyards (CMVs), all of which were phylloxera-infested. In both years, root samples from OMVs showed significantly less fungal pathogen-caused root necrosis than samples from CMVs, averaging 9% in OMVs and 31% in CMVs. There was no significant difference in phylloxera populations per 100 g of root between OMVs and CMVs, although there was a trend toward higher populations in CMVs. Soil characteristics, percent organic matter, total nitrogen, nitrate, and percent sand/silt/clay were not significantly different between the two regimes. Cultures of necrotic root tissue showed significantly higher levels of the benefical fungus Trichoderma in OMVs in 1997 but not in 1998, and there were significantly higher levels of the pathogens Fusarium oxysporum and Cylindrocarpon spp. in CMVs in 1998 but not in 1997. Implications for further research and viticulture are discussed.
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El-Kazzaz, M. K., M. M. Badr, H. M. El-Zahaby, and M. I. Gouda. "Biological control of seedling damping-off and root rot of sugar beet plants." Plant Protection Science 38, SI 2 - 6th Conf EFPP 2002 (December 31, 2017): 645–47. http://dx.doi.org/10.17221/10580-pps.
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Some fungal and bacterial bioagents as well as an Actinomycete isolate were screened for their antagonistic effects against S. rolfsii, R. solani, M. phaseolina, F. oxysporum and F. solani in vitro. Trichoderma hamatum, T. harzianum, T. pseudokningii, certain isolates of Bacillus subtilis and one isolate of Pseudomonas fluorescens were the most effective bioagents in suppressing the radial growth of the four pathogens, in general. Yet, they were less effective in retarding growth of Fusarium spp. as compared with the other pathogens under study. Studying biological control showed the possibility of controlling sugar beet damping-off and root rot by certain bioagents as T. hamatum, T. hazianum, Pseudomonas fluorescens and B. subtilis under greenhouse (S. rolfsii-infested soil) and field (natural infection) conditions. These treatments also caused and increase root yield per plot.
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Gould, J., and D. H. Northcote. "Cell-cell recognition of host surfaces by pathogens. The adsorption of maize (Zea mays) root mucilage by surfaces of pathogenic fungi." Biochemical Journal 233, no. 2 (January 15, 1986): 395–405. http://dx.doi.org/10.1042/bj2330395.
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The adsorption of radioactive mucilage by pathogenic fungi was shown to be dependent upon time, the composition of mucilage, the type of fungal surface (conidia, hyphae, hyphal apices), fungal species, pH and bivalent cations. All fungal adhesins were inactivated by either proteinase or polysaccharase treatments. Adsorption was not inhibited by the numberous mono-, di- and oligo-saccharides that were tested individually, but it was inhibited absolutely by several polysaccharides. This suggested that adsorption of mucilage by pathogens involved conformational and ionic interactions between plant and fungal polymers but not fungal lectins bound to sugar residues of mucilage. Several fractionation schemes showed that pathogens bound only the most acidic of the variety of polymers that comprise mucilage. There was not any absolute distinction between ability to bind radioactive mucilage and type of pathogen or non-pathogen. However, there were notable differences in characteristics of adsorption between two types of pathogen. Differences were revealed by comparison of the adsorption capacities of conidia and germinant conidia and chromatography of radioactive mucilage on germinant conidia. An ectotrophic root-infecting fungus (a highly specialized pathogen) bound a greater proportion of mucilage than did a vascular-wilt fungus (of catholic host and tissue range) with more than one class of site for adsorption. In contrast with the vascular-wilt fungus, sites for adsorption on the specialized pathogen were present solely on surfaces formed by germination.
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Madriz-Ordeñana, Kenneth, Hans Jørgen Lyngs Jørgensen, Andreea Balan, Daniel Madriz Sørensen, Kai Lønne Nielsen, and Hans Thordal-Christensen. "Prevalence of Soil-borne Diseases in Kalanchoe blossfeldiana Reveals a Complex of Pathogenic and Opportunistic Fungi." Plant Disease 103, no. 10 (October 2019): 2634–44. http://dx.doi.org/10.1094/pdis-12-18-2252-re.
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Greenhouse cultivation of ornamentals is subjected to a high incidence of soil-borne fungal pathogens. In Kalanchoe, these pathogens are responsible for root and stem rot, and for infection of the vascular tissue. Well-known soil-borne pathogens are believed to cause these diseases. Yet, a systematized survey of these pathogens is lacking for Kalanchoe produced commercially. Here, we studied the occurrence of soil-borne fungal pathogens associated with cultivation of Kalanchoe in Denmark and production of cuttings and stock plants in greenhouse facilities located in Turkey and Vietnam. Molecular identification of pathogens complemented mycological identification and pathogenicity testing of the soil-borne fungal pathogens. This study revealed that the fungi Corynespora cassiicola, Thielaviopsis basicola, Fusarium solani, and F. oxysporum are the most prevalent pathogens associated with root and stem rotting and wilt of Kalanchoe under the conditions studied. Furthermore, the study showed that some of the pathogens are part of an infection complex comprising both primary and opportunistic fungal species. The fact that some of the pathogens were present in some regions, while absent in others, suggests how they move between greenhouse facilities on infected plant material. This study generated important information about the soil-borne fungal complex affecting Kalanchoe, which is useful for a better understanding of the biology of the disease and for designing control strategies.
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Yang, Haishui, Yajun Dai, Xiaohua Wang, Qian Zhang, Liqun Zhu, and Xinmin Bian. "Meta-Analysis of Interactions between Arbuscular Mycorrhizal Fungi and Biotic Stressors of Plants." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/746506.
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Naturally, simultaneous interactions occurred among plants, herbivores, and soil biota, that is, arbuscular mycorrhizal fungi (AMF), nematodes, and fungal pathogens. These multiple interactions play fundamental roles in driving process, structure, and functioning of ecosystems. In this study, we conducted a meta-analysis with 144 papers to investigate the interactions between AMF and plant biotic stressors and their effects on plant growth performance. We found that AMF enhanced plant tolerance to herbivores, nematodes, and fungal pathogens. We also found reciprocal inhibition between AMF and nematodes as well as fungal pathogens, but unidirectional inhibition for AMF on herbivores. Negative effects of AMF on biotic stressors of plants depended on herbivore feeding sites and actioning modes of fungal pathogens. More performance was reduced in root-feeding than in shoot-feeding herbivores and in rotting- than in wilt-fungal pathogens. However, no difference was found for AMF negative effects between migratory and sedentary nematodes. In return, nematodes and fungal pathogens generated more reduction of root colonization in Non-Glomeraceae than in Glomeraceae. Our results suggested that AMF positive effects on plants might be indirectly mediated by competitive inhibition with biotic stressors of plants. These positive and negative interactions make potential contributions to maintaining ecosystem stability and functioning.
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Manandhar, Chetana, Suraj Baidya, Shrinkhala Manandhar, Bimala Pant, and Baidhya N. Mahto. "Plant Disease Diagnosis on Vegetable Crops from Different Locations of the Country." Journal of the Plant Protection Society 5 (December 31, 2018): 119–28. http://dx.doi.org/10.3126/jpps.v5i0.47121.
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Diseases are one of the major constraints on cultivation of crops and reduce production and productivity. Accurate disease diagnosis and proper identification is the first steps of disease management strategy. The activities of carrying out disease diagnosis help to know the distribution of the diseases in the country, explore new disease outbreak and its epidemiology, and provide information for disease management and support in research area prioritization. During fiscal year 2070/71, 252 different disease samples of different vegetable crops were received from various locations and sources for disease diagnosis. Examination of such samples identified 192 samples with fungal infection, 23 with bacterial infection, 28 with viral infection and 9 with nematode infection. In solanaceous crops, 70% disease caused by fungus and 11% by bacteria, 14% by virus and 5% by nematodes respectively. Likewise, in cucurbit crops, occurrence of pathogens is 61% fungal, 26% viral and 13% nematode respectively. The fugal pathogens were dominant in case of crucifer crops as well. The fungal pathogens were found in 79% of samples and followed by bacterial in 14% and viral in 7% respectively. Only fungal pathogen was detected in bulb and root crops. Fungal pathogens (76%) are the common problem in vegetable crops by followed by bacteria (9%) and virus pathogens (11%) and nematode (4%). The study revealed that management of fungal disease is prime concern to minimize the losses due to disease.
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Taylor, James T., Rebekka Harting, Samer Shalaby, Charles M. Kenerley, Gerhard H. Braus, and Benjamin A. Horwitz. "Adhesion as a Focus in Trichoderma–Root Interactions." Journal of Fungi 8, no. 4 (April 6, 2022): 372. http://dx.doi.org/10.3390/jof8040372.
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Fungal spores, germlings, and mycelia adhere to substrates, including host tissues. The adhesive forces depend on the substrate and on the adhesins, the fungal cell surface proteins. Attachment is often a prerequisite for the invasion of the host, hence its importance. Adhesion visibly precedes colonization of root surfaces and outer cortex layers, but little is known about the molecular details. We propose that by starting from what is already known from other fungi, including yeast and other filamentous pathogens and symbionts, the mechanism and function of Trichoderma adhesion will become accessible. There is a sequence, and perhaps functional, homology to other rhizosphere-competent Sordariomycetes. Specifically, Verticillium dahliae is a soil-borne pathogen that establishes itself in the xylem and causes destructive wilt disease. Metarhizium species are best-known as insect pathogens with biocontrol potential, but they also colonize roots. Verticillium orthologs of the yeast Flo8 transcription factor, Som1, and several other relevant genes are already under study for their roles in adhesion. Metarhizium encodes relevant adhesins. Trichoderma virens encodes homologs of Som1, as well as adhesin candidates. These genes should provide exciting leads toward the first step in the establishment of beneficial interactions with roots in the rhizosphere.
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Posada-Vergara, Catalina, Stefan Vidal, and Michael Rostás. "Local Competition and Enhanced Defense: How Metarhizium brunneum Inhibits Verticillium longisporum in Oilseed Rape Plants." Journal of Fungi 9, no. 8 (July 28, 2023): 796. http://dx.doi.org/10.3390/jof9080796.
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Metarhizium brunneum is a soil-borne fungal entomopathogen that can be associated with plant roots. Previous studies have demonstrated that root colonization by beneficial fungi can directly affect soil-borne pathogens through competition and antibiosis and can activate a systemic response in plants, resulting in a primed state for a faster and/or stronger response to stressors. However, the mechanisms by which Metarhizium inoculation ameliorates symptoms caused by plant pathogens are not well known. This study evaluated the ability of M. brunneum to protect oilseed rape (Brassica napus L.) plants against the soil-borne pathogen Verticillium longisporum and investigated whether the observed effects are a result of direct interaction and/or plant-mediated effects. In vitro and greenhouse experiments were conducted to measure fungal colonization of the rhizosphere and plant tissues, and targeted gene expression analysis was used to evaluate the plant response. The results show that M. brunneum delayed pathogen colonization of plant root tissues, resulting in decreased disease symptoms. Direct competition and antibiosis were found to be part of the mechanisms, as M. brunneum growth was stimulated by the pathogen and inhibited the in vitro growth of V. longisporum. Additionally, M. brunneum changed the plant response to the pathogen by locally activating key defense hormones in the salicylic acid (SA) and abscisic acid (ABA) pathways. Using a split-root setup, it was demonstrated that there is a plant-mediated effect, as improved plant growth and decreased disease symptoms were observed when M. brunneum was in the systemic compartment. Moreover, a stronger systemic induction of the gene PR1 suggested a priming effect, involving the SA pathway. Overall, this study sheds light on the mechanisms underlying the protective effects of M. brunneum against soil-borne pathogens in oilseed rape plants, highlighting the potential of this fungal entomopathogen as a biocontrol agent in sustainable agriculture.
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Chadha, Neha, Manjita Mishra, Ram Prasad, and Ajit Varma. "Root Endophytic Fungi: Research Update." Journal of Biology and Life Science 5, no. 2 (July 12, 2014): 135. http://dx.doi.org/10.5296/jbls.v5i2.5960.
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Fungal endophytes are group of microorganisms that reside asymptomatically within the healthy living tissue. Root endophytic fungi like dark septate endophytes (DSE), Piriformospora indica, and Trichoderma show mutualistic association with many plant species. The endophytes are known to produce a diverse group of secondary metabolites, extracellular enzymes, antibiotics, antifungal, anticancer agents that can be used as therapeutic drugs, agrochemicals or in industries. Plants associated with fungal endophytes play an important role in the survival of plants in extreme stressed condition. This review focuses on the functions of fungal root endophytes, their relationship with host plant, tolerance to abiotic stress and secondary metabolites production against various pathogens.
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Sabet, Kamel Kamal, Magdy Mohamed Saber, Mohamed Adel-Aziz El-Naggar, Nehal Samy El-Mougy, Hatem Mohamed El-Deeb, and Ibrahim El-Saied El-Shahawy. "Using Commercial Compost as Control Measures against Cucumber Root-Rot Disease." Journal of Mycology 2013 (May 15, 2013): 1–13. http://dx.doi.org/10.1155/2013/324570.
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Five commercial composts were evaluated to suppress the root-rot pathogens (Fusarium solani (Mart.) App. and Wr, Pythium ultimum Trow, Rhizoctonia solani Kuhn, and Sclerotium rolfsii Sacc.) of cucumber plants under in vitro and greenhouse conditions. In vitro tests showed that all tested unautoclaved and unfiltrated composts water extracts (CWEs) had inhibitor effect against pathogenic fungi, compared to autoclaved and filtrated ones. Also, the inhibitor effects of 40 bacteria and 15 fungi isolated from composts were tested against the mycelial growth of cucumber root-rot pathogens. Twenty two bacteria and twelve fungal isolates had antagonistic effect against root-rot pathogens. The antagonistic fungal isolates were identified as 6 isolates belong to the genus Aspergillus spp., 5 isolates belong to the genus Penicillium spp. and one isolate belong to the genus Chaetomium spp. Under greenhouse conditions, the obtained results in pot experiment using artificial infested soil with cucumber root-rot pathogens showed that the compost amended soil reduced the percentage of disease incidence, pathogenic fungi population, and improved the cucumber vegetative parameters as shoot length, root length, fresh weight, and dry weight. These results suggested that composts are consequently considered as control measure against cucumber root-rot pathogens.
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Wang, Qing, Stefanie Vera Buxa, Alexandra Furch, Wolfgang Friedt, and Sven Gottwald. "Insights Into Triticum aestivum Seedling Root Rot Caused by Fusarium graminearum." Molecular Plant-Microbe Interactions® 28, no. 12 (December 2015): 1288–303. http://dx.doi.org/10.1094/mpmi-07-15-0144-r.
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Fusarium graminearum is one of the most common and potent fungal pathogens of wheat (Triticum aestivum), known for causing devastating spike infections and grain yield damage. F. graminearum is a typical soil-borne pathogen that builds up during consecutive cereal cropping. Speculation on systemic colonization of cereals by F. graminearum root infection have long existed but have not been proven. We have assessed the Fusarium root rot disease macroscopically in a diverse set of 12 wheat genotypes and microscopically in a comparative study of two genotypes with diverging responses. Here, we show a ‘new’ aspect of the F. graminearum life cycle, i.e., the head blight fungus uses a unique root-infection strategy with an initial stage typical for root pathogens and a later stage typical for spike infection. Root colonization negatively affects seedling development and leads to systemic plant invasion by tissue-adapted fungal strategies. Another major outcome is the identification of partial resistance to root rot. Disease severity assessments and histological examinations both demonstrated three distinct disease phases that, however, proceeded differently in resistant and susceptible genotypes. Soil-borne inoculum and root infection are considered significant components of the F. graminearum life cycle with important implications for the development of new strategies of resistance breeding and disease control.
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Thapa, Rabindra, and Sanjay Kumar Jha. "Study of fungal diseases on Swertia chirayita from cultivated fields of Dolakha district, central Nepal." Our Nature 20, no. 1 (June 6, 2022): 41–47. http://dx.doi.org/10.3126/on.v20i1.44951.
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Swertia chirayita is a medicinally and economically important herb of the family Gentinaceae. It is one of the highly traded, traditionally important medicinal plants. Fungal Pathogens corrupt the quality and amount of Swertia chirayita development, and production and cause terrible well-being of plants as well as monetary problem to the traders. This study was carried out to identify some diseases associated with S. chirayita cultivated fields in Bigu, Khartal, and Boch regions of Dolakha district. The samples were collected from selected sites and cultured on Potato Dextrose Agar media for fungal pathogens. During the investigation, five species of fungal pathogens were identified. Alternaria alternata, Colletotrichum gleosporioides and Curvularia sp. were isolated from leaf. They caused Alternaria leaf spot, Colletotrichum leaf blight, and Curvularia leaf spot. Similarly, stem possesses canker disease and root had root canker, Fusarium oxysporum causing Fusarium wilt, Rhizoctonia sp. causing Rhizoctonia root rot. The presence of illnesses in S. chirayita shows the need for proper plant care.
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Lade, Sarah B., Dora Štraus, and Jonàs Oliva. "Variation in Fungal Community in Grapevine (Vitis vinifera) Nursery Stock Depends on Nursery, Variety and Rootstock." Journal of Fungi 8, no. 1 (January 3, 2022): 47. http://dx.doi.org/10.3390/jof8010047.
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Grapevine trunk diseases (GTDs) are caused by cryptic complexes of fungal pathogens and have become a growing problem for new grapevine (Vitis vinifera) plantations. We studied the role of the nursery, variety, and rootstock in the composition of the fungal communities in root collars and graft unions of planting material in Catalonia (NE Spain). We compared necrosis and fungal communities in graft unions and root collars at harvest, and then after three months of cold storage. We evaluated combinations of eleven red and five white varieties with four common rootstocks coming from six nurseries. Fungal communities were characterized by isolation and metabarcoding of the ITS2 region. Our data suggests that nursery followed by rootstock and variety had significant effects on necrosis and fungal community structure in graft and root tissues. Within the plant, we found large differences in terms fungal community distribution between graft and root tissues. Graft unions housed a significantly higher relative abundance of GTD-related Operational Taxonomic Units (OTUs) than root collars. More severe necrosis was correlated with a lower relative abundance of GTD-related OTUs based on isolation and metabarcoding analyses. Our results suggest that nurseries and therefore their plant production practices play a major role in determining the fungal and GTD-related fungal community in grapevine plants sold for planting. GTD variation across rootstocks and varieties could be explored as a venue for minimizing pathogen load in young plantations.
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Schlatter, Daniel C., Ian Burke, and Timothy C. Paulitz. "Succession of Fungal and Oomycete Communities in Glyphosate-Killed Wheat Roots." Phytopathology® 108, no. 5 (May 2018): 582–94. http://dx.doi.org/10.1094/phyto-06-17-0212-r.
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The successional dynamics of root-colonizing microbes are hypothesized to be critical to displacing fungal pathogens that can proliferate after the use of some herbicides. Applications of glyphosate in particular, which compromises the plant defense system by interfering with the production of aromatic amino acids, are thought to promote a buildup of root pathogens and can result in a “greenbridge” between weeds or volunteers and crop hosts. By planting 2 to 3 weeks after spraying, growers can avoid most negative impacts of the greenbridge by allowing pathogen populations to decline, but with the added cost of delayed planting dates. However, the specific changes in microbial communities during this period of root death and the microbial taxa likely to be involved in displacing pathogens are poorly characterized. Using high-throughput sequencing, we characterized fungal and oomycete communities in roots after applications of herbicides with different modes of action (glyphosate or clethodim) and tracked their dynamics over 3 weeks in both naturally infested soil and soil inoculated with Rhizoctonia solani AG-8. We found that many unexpected taxa were present at high relative abundance (e.g., Pythium volutum and Myrmecridium species) in live and dying wheat roots and may play an under-recognized role in greenbridge dynamics. Moreover, communities were highly dynamic over time and had herbicide-specific successional patterns, but became relatively stable by 2 weeks after herbicide application. Network analysis of communities over time revealed patterns of interactions among taxa that were both common and unique to each herbicide treatment and identified two primary groups of taxa with many positive associations within-groups but negative associations between-groups, suggesting that these groups are antagonistic to one another in dying roots and may play a role in displacing pathogen populations during greenbridge dynamics.
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Kurze, Stefan, Hubert Bahl, Robert Dahl, and Gabriele Berg. "Biological Control of Fungal Strawberry Diseases by Serratia plymuthica HRO-C48." Plant Disease 85, no. 5 (May 2001): 529–34. http://dx.doi.org/10.1094/pdis.2001.85.5.529.
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To develop a biological control product for commercial strawberry production, the chitinolytic rhizobacterium Serratia plymuthica strain HRO-C48 was evaluated for plant growth promotion of strawberries and biological control of the fungal pathogens Verticillium dahliae and Phytophthora cactorum. In phytochamber experiments, treatment with S. plymuthica HRO-C48 resulted in a statistically significant enhancement of plant growth dependent on the concentration of the bacterium that was applied. In greenhouse trials, bacterial treatment reduced the percentage of Verticillium wilt (18.5%) and Phytophthora root rot (33.4%). In three consecutive vegetation periods, field trials were carried out in soil naturally infested by both soilborne pathogens on commercial strawberry farms located in various regions of Germany. Dipping plants in a suspension of S. plymuthica prior to planting reduced Verticillium wilt compared with the nontreated control by 0 to 37.7%, with an average of 24.2%, whereas the increase of yield ranged from 156 to 394%, with an average of 296%. Bacterial treatment reduced Phy-tophthora root rot by 1.3 to 17.9%, with an average of 9.6%, and increased strawberry yield by 60% compared with the nontreated control. Under field conditions, strain HRO-C48 survived at approximately log10 3 to 7 CFU/g of root in the strawberry rhizosphere at 14 months after root application. Although results of the field trials were influenced by pathogen inoculum density, cropping history of the field site, and weather conditions, S. plymuthica HRO-C48 successfully controlled wilt and root rot of strawberry.
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Nowicki, Bogdan. "Occurrence of root parsley pathogens inhabiting seeds." Acta Agrobotanica 50, no. 1-2 (2013): 27–34. http://dx.doi.org/10.5586/aa.1997.003.
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The studies on root parsley pathogens inhabiting seeds were conducted during 1981-1988 and in 1993. Filter paper method with prefreezing and keeping under light was used. Each test sample comprised 500 seeds. Pathogenicity of collected fungal isolates was tested following two laboratory methods. 238 seed samples were studied. 18 fungal species were found but only 7 proved to be important pathogens of root parsley. The most common inhabitants of root parsley seeds were <em>Alternaria</em> spp. <em>A.allernata</em> occurred on 74,8% of seeds but only a few isolates showed to be slightly pathogenic while <em>A.petroselini</em> and <em>A.radicina</em> were higly pathogenic and inhabited 11,4 and 4,2% of seeds, respectively. The second group of important pathogens were species of <em>Fusarium</em> found on 3,9% of seeds. <em>F.avenaceum</em> dominated as it comprised 48% of <em>Fusarium</em> isolates, the next were as follow: <em>F.culmorum</em> - 20%, <em>F.equiseti</em> - 15%, <em>F.solani</em> - 8%, <em>F.oxysporum</em> - 7% and <em>F.dimerum</em> -2%. Some fungi like <em>Botrytis cinerea, Septoria petroselini</em> and <em>Phoma</em> spp. inhabited low number of seeds, respectively O,4; 0,5 and 0,8%, but they were highly pathogenic to root parsley. The fungi: <em>Bipolaris sorokiniana, Drechslera biseptata, Stemphylium botryosum</em> and <em>Ulocludium consortiale</em> showed slight pathogenicity. They were isolated from 3,8% of seeds.
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Gautam, R., SK Singh, and V. Sharma. "Suppression of soil-borne root pathogens of arid legumes by Sinorhizobium saheli." SAARC Journal of Agriculture 13, no. 1 (July 15, 2015): 63–74. http://dx.doi.org/10.3329/sja.v13i1.24181.
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The productivity of arid legumes in arid and semi-arid tracks remains virtually stagnant over decades because of their susceptibility to root diseases. The information on interaction of beneficial nitrogen fixing rhizobia with particular reference to arid legumes of the region is limited. Systematic studies on predominant species Sinorhizobium saheli in management of root pathogens in arid legumes were undertaken. In-vitro interactions of root pathogens and S. saheli isolated from arid legumes significantly suppressed the growth of all fungal pathogens in presence of S. saheli. In addition the growth of Rhizobium was stimulated in presence of different root pathogens. A field experiment on integrated disease managementexhibited that the maximum root nodulation with the maximum seed yield of 1325 kg/ha was observed from treatment where seeds were treated with S. saheli. Whereas, the minimum root nodulation was recorded in treatment, where a mixture of isolated fungal root pathogens were co-inoculated with S. Saheli was recorded from cowpea. The minimum seed yield was recorded from treatment wherein the mixture of isolated root pathogens of arid legumes was co-inoculated with S. Saheli due to increased disease pressure. The results of in-vitro and in-vivo efficacy of S. saheli strains suggest that their co-inoculation with PGPRs can not only reduce the use of chemical fertilizers but also can significantly enhance yields by increasing plant growth and suppressing soil borne plant pathogenic fungi.SAARC J. Agri., 13(1): 63-74 (2015)
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Skipp, R. A. "Fungal root pathogens in pasture soils and effects of fungicides." Proceedings of the New Zealand Weed and Pest Control Conference 39 (January 8, 1986): 60–64. http://dx.doi.org/10.30843/nzpp.1986.39.9425.
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Sales Júnior, Rui, Ana Paula Medeiros dos Santos Rodrigues, Andreia Mitsa Paiva Negreiros, Márcia Michelle de Queiroz Ambrósio, Hailton da Silva Barboza, and Roberto Beltrán. "WEEDS AS POTENTIAL HOSTS FOR FUNGAL ROOT PATHOGENS OF WATERMELON." Revista Caatinga 32, no. 1 (March 2019): 1–6. http://dx.doi.org/10.1590/1983-21252019v32n101rc.
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ABSTRACT Many watermelon (Citrullus lanatus) diseases are caused by soilborne pathogens in Brazil and worldwide. The goal of this study was to identify and quantify the frequency of phytopathogenic fungi associated with watermelon root rot and vine decline that were also present in the roots of weeds in the major watermelon production regions in the state of Rio Grande do Norte, Brazil. We collected root samples from 10 of the most prevalent weed species in 16 watermelon producing areas. The plants were identified and their frequencies in the fields were calculated. The fungi found in the weed roots were isolated and the main genera associated with watermelon vine decline were identified. We identified 13 weed species belonging to nine botanical families. The weed species with the highest frequencies found in the field were Amaranthus spinosus (25.0%), Trianthema portulacastrum (18.8%), Commelina sp. (18.8%), and Boerhavia diffusa (12.5%). The fungi Macrophomina, Rhizoctonia, and Monosporascus were isolated from the roots of the weed plants. While Macrophomina was isolated from 12 different types of plants, Rhizoctonia and Monosporascus were isolated from four and two different plant species, respectively.
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Biernacki, M., and B. D. Bruton. "Quantitative Response of Cucumis melo Inoculated with Root Rot Pathogens." Plant Disease 85, no. 1 (January 2001): 65–70. http://dx.doi.org/10.1094/pdis.2001.85.1.65.
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This experiment quantified the effects of three root rot pathogens on muskmelon (Cucumis melo L., var. cantalupensis) growth traits using computerized image analysis. Plants were grown from seed in sand infested with the soilborne pathogen Monosporascus cannonballus, Acremonium cucurbitacearum, or Rhizopycnis vagum. After 28 days in the growth chamber, images of plants were analyzed to quantify their response. Compared to noninoculated muskmelons, inoculated plants had significantly increased mean root diameter (45%), decreased root length (26%, primarily in roots of <0.5 mm diameter), decreased number of root tips (27%), decreased rhizosphere volume (40%), and decreased cumulative and mean surface area of leaves (24%). Effects of M. cannonballus on muskmelon growth were significantly different compared to A. cucurbitacearum and R. vagum. Isolate effects manifested a greater magnitude of difference on muskmelon traits than those observed at the species level. Multivariate analyses of plant responses were more powerful than univariate analyses to differentiate among effects of pathogen species and pathogen isolates. Discriminant analysis were useful to identify groups of plant traits modified by each fungal species or isolate at low disease levels. Digital image analyses proved to be a useful technique in quantitative assessment of plant damage caused by soilborne root rot pathogens.
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Nigam, Rashmi, and Joginder Singh. "RESPONSE OF PH ON INDEGENOUS BIOCONTROL ACTIVITY OF FUNGAL AND BACTERIAL BIOLOGICAL AGENTS AGAINST RHIZOCTONIA SOLANI." JOURNAL OF ECO-FRIENDLY AGRICULTURE 18, no. 2 (2023): 365–69. http://dx.doi.org/10.48165/jefa.2023.18.02.27.
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Root rot incited by Rhizoctonia solani is one the major diseases of pea. As there are no long term management strategies for this soil borne pathogens therefore, the study was carried out to determine the effect of pH on the antagonistic activity of fungal and bacterial isolates (Th3 and Th5 (Trichoderma harzianum), An1 (Aspergillus niger), Po3 (Penicillium oxalicum) and PS1, PS2 and PS5 (Flourescent Pseudomonas) against Rhizoctonia solani at four different pH levels (5.0, 6.0, 7.0 and 8.0). All the seven indigenous fungal and bacterial isolates evaluated for their antagonistic potential against root-rot pathogen, significantly retarded the radial growth of Rhizoctonia solani in comparison to control at four different pH levels (5.0, 6.0, 7.0 and 8.0).The observations of the study revealed that all bio agents significantly inhibited the growth of the Rhizoctonia solani . Similarly, Trichoderma species had significant effects on the number and size of sclerotia. The pH range of 6.0-8.0 were found optimum for Trichoderma spp. while Flourescent Pseudomonas shows best antagonistic activity at pH 7.0. As far as the effect of pH levels is concerned, all the promising fungal and bacterial isolates caused maximum growth inhibition of test pathogens at pH 6.0 to 7.0.
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Ziedan, El-Sayed, Ibrahim Elewa, Mostafa Mostafa, and Ahmed Sahab. "Application of Mycorrhizae for Controlling Root Diseases of Sesame." Journal of Plant Protection Research 51, no. 4 (October 1, 2011): 355–61. http://dx.doi.org/10.2478/v10045-011-0058-0.
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Application of Mycorrhizae for Controlling Root Diseases of Sesame Vesicular arbuscular mycorrhizae fungi (VAM) was evaluated as a biotic agent for controlling wilt and root-rot diseases of sesame caused by Fusarium oxysporum f. sp. sesami (Zap.) Cast and Macrophomina phaseolina (Moubl) Ashby pathogens can infect sesame plant at any growth stage causing considerable losses of seed yield. Spores of VA mycorrhizae fungi (Glomus spp.) were collected from the soil around the root systems of sesame plants then propagated on roots of Suddan grass (Sorghum vulgare var. sudanese). Under green house and field conditions, two hundreds sporocarps of Glomus spp. were added as a soil drench beside the sesame plant. Glomus spp. (VA mycorrhizae) significantly reduced wilt and root-rot incidence of sesame plants. Lums spp. (VA mycorrhizae) also significantly increased plant morphological characters such as plant height, number of branches and number of pods for each plant. Application of Glomus spp. to protect sesame plants by colonizing the root system, significantly reduced colonization of fungal pathogens in sesame rhizosphere as well as pathogenic activity of fungal pathogens increased lignin contents in the sesame root system were also observed. Furthermore, mycorrhizae treatment provided selective bacterial stimulation for colonization on sesame rhizosphere. These bacteria belonging the Bacillus group showed highly antagonistic potential to fungal pathogens. Application of mycorrhizae together with other biocontrol agent such as Trichoderma viride or Bacillus subtilis significantly effected than individual treatments for controlling these diseases incidences and increasing morphological characters and seed yield of sesame.
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Dawadi, Sujan, Fulya Baysal-Gurel, Karla M. Addesso, Prabha Liyanapathiranage, and Terri Simmons. "Fire Ant Venom Alkaloids: Possible Control Measure for Soilborne and Foliar Plant Pathogens." Pathogens 10, no. 6 (May 27, 2021): 659. http://dx.doi.org/10.3390/pathogens10060659.
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The purpose of this study was to evaluate fire ant venom alkaloids and an alarm pheromone analog against several plant pathogens, including Botrytis cinerea, Fusarium oxysporum, Phytophthora nicotianae, P. cryptogea, Pseudomonas syringae, Phytopythium citrinum, Rhizoctonia solani, Sclerotonia rolfsii, Xanthomonas axonopodis, and X. campestris. All pathogens were tested against red imported fire ant venom alkaloid extract and alarm pheromone compound for growth inhibition in in vitro assay. The venom alkaloid extract inhibited fungal and oomycete pathogens. Neither of the treatments were effective against bacterial pathogens. Three soilborne pathogens, P. nicotianae, R. solani, F. oxysporum, and one foliar pathogen, B. cinerea were selected for further in-vivo assays on impatiens (Impatiens walleriana ‘Super Elfin XP violet’). Total plant and root weight were higher in venom alkaloid treated plants compared to an inoculated control. The venom alkaloid treatment reduced damping-off, root rot severity, and pathogen recovery in soilborne pathogen inoculated plants. Similarly, venom alkaloid reduced Botrytis blight. However, higher venom rates caused foliar phytotoxicity on plants. Therefore, additional work is needed to evaluate rates of venom alkaloids or formulations to eliminate negative impacts on plants. Overall, these results suggest that red imported fire ant venom alkaloids may provide a basis for new products to control soilborne and foliar plant pathogens.
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Gunawardena, Uvini, and Martha C. Hawes. "Tissue Specific Localization of Root Infection by Fungal Pathogens: Role of Root Border Cells." Molecular Plant-Microbe Interactions® 15, no. 11 (November 2002): 1128–36. http://dx.doi.org/10.1094/mpmi.2002.15.11.1128.
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When roots of pea seedlings were inoculated uniformly with spores of Nectria haematocca or other pea pathogenic fungi, more than 90% developed lesions in the region of elongation within 3 days. More mature regions of most roots as well as the tip showed no visible signs of infection. Yet, microscopic observation revealed that ‘mantles,’ comprised of fungal hyphae intermeshed with populations of border cells, covered the tips of most roots. After physical detachment of the mantle, the underlying tip of most roots was found to be free of infection. Mantle-covered root tips did not respond to invasion of their border cells by activation of known defense genes unless there was invasion of the tip itself, as revealed by the presence of a lesion. Concomitant with the activation of defense genes was the induction of a cell-wall degrading enzyme whose expression is a marker for renewed production of border cells. Mantle formation did not occur in response to nonpathogens. The data are consistent with the hypothesis that border cells serve as a host-specific ‘decoy’ that protects root meristems by inhibiting fungal infection of the root tip.
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Zhang, Jiahui, Yanli Wei, Hongmei Li, Jindong Hu, Zhongjuan Zhao, Yuanzheng Wu, Han Yang, Jishun Li, and Yi Zhou. "Rhizosphere Microbiome and Phenolic Acid Exudation of the Healthy and Diseased American Ginseng Were Modulated by the Cropping History." Plants 12, no. 16 (August 19, 2023): 2993. http://dx.doi.org/10.3390/plants12162993.
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The infection of soil-borne diseases has the potential to modify root exudation and the rhizosphere microbiome. However, the extent to which these modifications occur in various monocropping histories remains inadequately explored. This study sampled healthy and diseased American ginseng (Panax quinquefolius L.) plants under 1–4 years of monocropping and analyzed the phenolic acids composition by HPLC, microbiome structure by high-throughput sequencing technique, and the abundance of pathogens by quantitative PCR. First, the fungal pathogens of Fusarium solani and Ilyonectria destructans in the rhizosphere soil were more abundant in the diseased plants than the healthy plants. The healthy American ginseng plants exudated more phenolic acid, especially p-coumaric acid, compared to the diseased plants after 1–2 years of monocropping, while this difference gradually diminished with the increase in monocropping years. The pathogen abundance was influenced by the exudation of phenolic acids, e.g., total phenolic acids (r = −0.455), p-coumaric acid (r = −0.465), and salicylic acid (r = −0.417), and the further in vitro test confirmed that increased concentration of p-coumaric acid inhibited the mycelial growth of the isolated pathogens for root rot. The healthy plants had a higher diversity of rhizosphere bacterial and fungal microbiome than the diseased plants only after a long period of monocropping. Our study has revealed that the cropping history of American ginseng has altered the effect of pathogens infection on rhizosphere microbiota and root exudation.
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Iqbal, Mudassir, Maha Jamshaid, Muhammad Awais Zahid, Erik Andreasson, Ramesh R. Vetukuri, and Johan A. Stenberg. "Biological control of strawberry crown rot, root rot and grey mould by the beneficial fungus Aureobasidium pullulans." BioControl 66, no. 4 (March 18, 2021): 535–45. http://dx.doi.org/10.1007/s10526-021-10083-w.
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AbstractUtilization of biocontrol agents is a sustainable approach to reduce plant diseases caused by fungal pathogens. In the present study, we tested the effect of the candidate biocontrol fungus Aureobasidium pullulans (De Bary) G. Armaud on strawberry under in vitro and in vivo conditions to control crown rot, root rot and grey mould caused by Phytophthora cactorum (Lebert and Cohn) and Botrytis cinerea Pers, respectively. A dual plate confrontation assay showed that mycelial growth of P. cactorum and B. cinerea was reduced by 33–48% when challenged by A. pullulans as compared with control treatments. Likewise, detached leaf and fruit assays showed that A. pullulans significantly reduced necrotic lesion size on leaves and disease severity on fruits caused by P. cactorum and B. cinerea. In addition, greenhouse experiments with whole plants revealed enhanced biocontrol efficacy against root rot and grey mould when treated with A. pullulans either in combination with the pathogen or pre-treated with A. pullulans followed by inoculation of the pathogens. Our results demonstrate that A. pullulans is an effective biocontrol agent to control strawberry diseases caused by fungal pathogens and can be an effective alternative to chemical-based fungicides.
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Lotter, D. W., J. Granett, and A. D. Omer. "Differences in Grape Phylloxera-related Grapevine Root Damage in Organically and Conventionally Managed Vineyards in California." HortScience 34, no. 6 (October 1999): 1108–11. http://dx.doi.org/10.21273/hortsci.34.6.1108.
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Secondary infection of roots by fungal pathogens is a primary cause of vine damage in phylloxera-infested grapevines (Vitis vinifera L.). In summer and fall surveys in 1997 and 1998, grapevine root samples were taken from organically (OMVs) and conventionally managed vineyards (CMVs), all of which were phylloxera-infested. In both years, root samples from OMVs showed significantly less root necrosis caused by fungal pathogens than did samples from CMVs, averaging 9% in OMVs vs. 31% in CMVs. Phylloxera populations per 100 g of root did not differ significantly between OMVs and CMVs, although there was a trend toward higher populations in OMVs. Soil parameters, percent organic matter, total nitrogen, nitrate, and percent sand/silt/clay also did not differ significantly between the two regimes. Cultures of necrotic root tissue showed significantly higher levels of the beneficial fungus Trichoderma in OMVs in 1997 but not in 1998, and there were significantly higher levels of the pathogens Fusarium oxysporum and Cylindrocarpon sp. in CMVs in 1998 but not in 1997. Implications for further research and for viticulture are discussed.
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Al-Ani, R. A., M. A. Adhab, M. H. Mahdi, and H. M. Abood. "Rhizobium japonicum as a biocontrol agent of soybean root rot disease caused by Fusarium solani and Macrophomina phaseolina." Plant Protection Science 48, No. 4 (November 6, 2012): 149–55. http://dx.doi.org/10.17221/16/2012-pps.
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The activity of Rhizobium japonicum against the soil-borne pathogens Fusarium solani and Macrophomina phaseolina as causative agents of soybean root rot disease in both culture medium and soil was evaluated. Rhizobial culture filtrate caused an inhibition of the fungal radial growth of Fusarium solani and Macrophomina phaseolina on potato dextrose agar medium amended with the filtrate compared with control. The addition of rhizobial culture suspension to the soil contaminated by the two pathogens, Fusarium solani and Macrophomina phaseolina and their interaction, in pots, improved seed germination percentages and reduced the root rot disease index significantly. The sowing of rhizobial coated seeds in soil contaminated by Fusarium solani and Macrophomina phaseolina separately and in combination, in the field, increased seed germination significantly and induced a high reduction in disease severity for the same previous combination under field conditions. These results indicate that rhizobia could be an important element in root rot disease management.
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Sealy, Ramsey, and Michael R. Evans. "EFFICACY OF BIOLOGICAL AMENDMENTS ON POSTTRANSPLANT ROOT ROT." HortScience 40, no. 3 (June 2005): 880b—880. http://dx.doi.org/10.21273/hortsci.40.3.880b.
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Biological substrate amendments including SG-11, Subtilex, SoilGuard, ActinoIron, Companion, RootShield and BioYield were evaluated for their efficacy to control common soil-borne fungal and fungal-like pathogens when incorporated into the substrate at transplanting. The biological agents were incorporated into an 80% Sphagnum peat and 20% perlite substrate at the label recommended rates and four-to-six-leaf plugs of the test species were transplanted into the substrates. Substrates were either inoculated or uninoculated with a test pathogen. Pathogen-host combinations included Pythium ultimum on geranium (Pelargonium ×hortorum), Phytophthora nicotianae and Pythium aphanidermatum on vinca (Catharanthus roseus), and Theilaviopsis basicoli on pansy (Viola ×wittrockiana). The incidence of disease development, plant mortality and root fresh weights did not differ among the biological agents and the inoculated controls. Therefore, under the conditions of this study, the biological agents did not provide significant disease suppression. Pansy and vinca plants grown in uninoculated substrates amended with Subtilex had significantly higher shoot dry weights than those grown in unamended substrates. Pansy, vinca and tomato plants grown in uninoculated substrates amended with SG-11 had significantly higher shoot dry weights than those grown in unamended substrates.
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Sommermann, Loreen, Doreen Babin, Jan Helge Behr, Soumitra Paul Chowdhury, Martin Sandmann, Saskia Windisch, Günter Neumann, et al. "Long-Term Fertilization Strategy Impacts Rhizoctonia solani–Microbe Interactions in Soil and Rhizosphere and Defense Responses in Lettuce." Microorganisms 10, no. 9 (August 26, 2022): 1717. http://dx.doi.org/10.3390/microorganisms10091717.
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The long-term effects of agricultural management such as different fertilization strategies on soil microbiota and soil suppressiveness against plant pathogens are crucial. Therefore, the suppressiveness of soils differing in fertilization history was assessed using two Rhizoctonia solani isolates and their respective host plants (lettuce, sugar beet) in pot experiments. Further, the effects of fertilization history and the pathogen R. solani AG1-IB on the bulk soil, root-associated soil and rhizosphere microbiota of lettuce were analyzed based on amplicon sequencing of the 16S rRNA gene and ITS2 region. Organic fertilization history supported the spread of the soil-borne pathogens compared to long-term mineral fertilization. The fertilization strategy affected bacterial and fungal community composition in the root-associated soil and rhizosphere, respectively, but only the fungal community shifted in response to the inoculated pathogen. The potential plant-beneficial genus Talaromyces was enriched in the rhizosphere by organic fertilization and presence of the pathogen. Moreover, increased expression levels of defense-related genes in shoots of lettuce were observed in the soil with organic fertilization history, both in the absence and presence of the pathogen. This may reflect the enrichment of potential plant-beneficial microorganisms in the rhizosphere, but also pathogen infestation. However, enhanced defense responses resulted in retarded plant growth in the presence of R. solani (plant growth/defense tradeoff).
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Hasan, Abul. "Breaking Resistance in Chilli To Root-Knot Nematode By Fungal Pathogens." Nematologica 31, no. 2 (1985): 210–17. http://dx.doi.org/10.1163/187529285x00274.
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Jiao, Xiao Lin, Wu Bi, Ming Li, Yong Luo, and Wei Wei Gao. "Dynamic response of ginsenosides in American ginseng to root fungal pathogens." Plant and Soil 339, no. 1-2 (September 30, 2010): 317–27. http://dx.doi.org/10.1007/s11104-010-0580-2.
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Agustini, L., A. Francis, M. Glen, H. Indrayadi, and C. L. Mohammed. "Signs and identification of fungal root-rot pathogens in tropicalEucalyptus pellitaplantations." Forest Pathology 44, no. 6 (December 2014): 486–95. http://dx.doi.org/10.1111/efp.12145.
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Lévesque, C. André, and James E. Rahe. "Herbicide Interactions with Fungal Root Pathogens, with Special Reference to Glyphosate." Annual Review of Phytopathology 30, no. 1 (September 1992): 579–602. http://dx.doi.org/10.1146/annurev.py.30.090192.003051.
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Nigam, Rashmi S., R. U. Khan, Reshu Singh, and Joginder Singh. "Bioefficacy of rhizospheric fungal isolates against wilt and root-rot pathogens of Pea." International Journal of Agricultural Invention 5, no. 01 (November 27, 2019): 133–37. http://dx.doi.org/10.46492/ijai/2020.5.1.20.
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Pea (Pisum sativum) is an important leguminous crop in many countries including India. Wilt and root rot of pea is an important and widespread disease that often causes significant reduction in the yield and quality of harvested peas throughout the production areas. It is the most important and widespread disease of pea grown in relatively dry and warm area. In-vitro effectiveness of various antagonistic fungal isolates namely T. harzianum (Th1, Th2, Th3, Th4 and Th5) was evaluated against Fusarium oxysporum f. sp. pisi, Rhizoctonia solani and Pythium ultimum by dual culture technique on potato dextrose agar. According to the observation recorded after 5 days, all the rhizospheric fungal isolates evaluated for their antagonistic potential against wilt and root-rot pathogens, exhibited significant effect on radial growth inhibition of pathogens in comparison to control. Among the fungal isolates, Th3 and Th5 of T. harzianum proved to be most effective in reducing the growth of F. oxysporum f. sp. pisi, R. solani and P. ultimum. It was worthy to note that all rhizospheric fungal isolates visualized an increase in their antagonistic potential over the period of time in subsequent hours of inoculation.
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Żółciak, Anna, Katarzyna Sikora, Marta Wrzosek, Marta Damszel, and Zbigniew Sierota. "Why Does Phlebiopsis gigantea not Always Inhibit Root and Butt Rot in Conifers?" Forests 11, no. 2 (January 21, 2020): 129. http://dx.doi.org/10.3390/f11020129.
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This review aims to identify possible causes of differing effectiveness of artificial biological control of Heterobasidion root rot by the saprotrophic fungus Phlebiopsis gigantea. We describe published information in terms of pathogen–competitor relationships and the impact of environmental and genetic factors. We also revisit data from original research performed in recent years at the Forest Research Institute in Poland. We hypothesized that, in many cases, competition in roots and stumps of coniferous trees between the necrotrophic Heterobasidion spp. and the introduced saprotroph, Phlebiopsis gigantea, is affected by growth characteristics and enzymatic activity of the fungi, the characteristics of the wood, and environmental conditions. We concluded that both wood traits and fungal enzymatic activity during wood decay in roots and stumps, and the richness of the fungal biota, may limit biological control of root rot. In addition, we identify the need for research on new formulations and isolates of the fungal competitor, Phlebiopsis gigantea, as well as on approaches for accurately identifying the infectious threat from pathogens.
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Baral, Bikash, Prabina Rana, and Bijaya Laxmi Maharjan. "ANTIMICROBIAL POTENTIALS OF ENDOPHYTIC FUNGI INHABITING RHODODENDRON ANTHOPOGON D. DON." Ecoprint: An International Journal of Ecology 18 (December 20, 2013): 39–44. http://dx.doi.org/10.3126/eco.v18i0.9397.
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Fungal endophytes have been studied from Rhododendron anthopogon D. Don Manaslu Conservation Area in Nepal. The endophytes were isolated from different parts of Rhododendron viz., root, stem and leaf using potato dextrose agar, malt extract agar and water agar. Altogether eighteen fungal endophytes belonging to nine genera were isolated. The endophytic species isolates belong to the genera Stemphylium, Alternaria, Penicillium, Aspergillus, Trichoderma, Papulaspora, Hansfordia, Wardomyces and Geotrichum. Out of 18 fungal isolates, 8 isolates could display antimicrobial activity inhibiting at least one of the test pathogens. Among the potent strains, 4 displayed both antibacterial and antifungal activities. Endophytic fungal isolates ERAA3, ERAA6 and ERAA8 displayed antimicrobial activity against all the tested bacterial (10) and fungal (5) pathogens. The endophytic strains were very effective against the bacterial pathogens and moderately active against the fungal pathogens. The study reinforced the assumption that endophytes of the high altitude medicinal plants could be a promising source of antimicrobial substances.DOI: http://dx.doi.org/10.3126/eco.v18i0.9397Ecoprint: An International Journal of EcologyVol. 18, 2011 Page: 39-44 Uploaded date: 12/20/2013
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Karadimos, Dimitros, and George Karaoglanidis. "Survey of root rot diseases of sugar bett in Central Greece." Zbornik Matice srpske za prirodne nauke, no. 110 (2006): 129–31. http://dx.doi.org/10.2298/zmspn0610129k.
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An extensive survey was conducted during the summer and autumn of 2004 in sugar beet fields in the area of Larissa, Thessaly region, with plants showing symptoms of root rot diseases. The aim of the monitoring was to identify the causal agents of root rot diseases. In total, 76 sugar beet fields were surveyed and 5-10 diseased roots were examined from each field. Isolations, carried out on PDA, showed that two main fungal pathogens causing root rot were Rhizoctonia solani and Phytophthora cryptogea. The former was isolated in 46% of the fields and the latter in 38% of the fields. In addition, Rhizopus stolonifer, Fusarium spp., Scerotium rolfsii and Rhizoctonia violacea were isolated in 14%, 7%, 4% and 1% of the fields respectively. In most of the surveyed fields only one pathogen species was isolated and only in a few of them more than one fungal species was identified.
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Abdela, Usmael, Dejene Mashilla, and Ayena Getachew. "Assessment of Root Rot Pathogens of Common Bean (Phaseolus Vulgaris L.) and Reaction of Genotypes to the Pathogens in West Hararghe Zone, Ethiopia." Open Journal of Plant Science 8, no. 1 (June 27, 2023): 037–55. http://dx.doi.org/10.17352/ojps.000056.
Full textAbstract:
Common bean root rot caused by fungal pathogens is an important disease affecting common bean crops in Ethiopia. Information on pathogen identification, characterization, and management options is lacking for the Ethiopian bean production system. This study aimed to assess the major causal fungal pathogens and their management through host resistance methods. Initially, a field survey was conducted in three districts in 2016. It was cored forty-five (45) common bean fields. In the mean time, disease samples were collected for laboratory analyses. Secondly, pathogen identification and characterization were done in Laboratory at Haramaya University, followed by a pathogenicity test. Thirdly, a genotypic reaction was done on twenty common bean varieties by using four fungal genera (F. oxysporum, S. rolfsii, M. phaseolina, and R. solani) as experimental materials that were arranged in (CRD) design with three replications. Out of forty-five (45) common bean fields assessed 33 farms exhibited the disease. In the pathogenicity test, all the isolates were found pathogenic and showed a significant (p < 0.05) difference. In addition, the analysis of variance also showed that out of the tested twenty varieties, some released varieties (Dandesu, Tinike, SER-125, Dursitu, and Chorie), Chorie and (Dursitu, Chorie, Cranscope, Argene and SAB 632) showed highly significant at (p≤ 0.001) to Fusarium oxysporum f.sp. phaseoli, Sclerotium rolfsii, and Rhizoctonia solani while they didn’t exhibit any significant (p < 0.05) difference to Macrophomina phaseolina. In conclusion, those varieties showing resistance characters were recommended for growers.