Foliar Application of Fungal Biocontrol Agents for the Control of White Mold of Dry Bean Caused by Sclerotinia sclerotiorum

2000 ◽  
Vol 18 (3) ◽  
pp. 270-276 ◽  
Author(s):  
H.C Huang ◽  
E Bremer ◽  
R.K Hynes ◽  
R.S Erickson
2009 ◽  
Vol 89 (4) ◽  
pp. 755-762 ◽  
Author(s):  
H Terán ◽  
S P Singh

White mold (WM) caused by Sclerotinia sclerotiorum (Lib.) de Bary is the most devastating disease of common bean (dry and snap or garden bean) (Phaseolus vulgaris L.) in North America. The use of a reliable screening method (SM) in common bean is crucial to improve physiological resistance to WM. The objective of this study was to compare the efficacy of three SM to identify physiological resistance in dry bean genotypes with different evolutionary origins and levels of resistance. Screening methods tested were: (i) the modified straw test or cut–stem (CSM); (ii) infected bean flower (IFL); and (iii) infected oat seed (IOS). A 195, ICA Bunsi, Othello, and VCW 54 dry bean were tested with the three SM. The experimental design was a split plot in randomized complete blocks with three replications in 2007 and 2008. Two independent inoculations 1 wk apart for each SM were made. The WM reaction was scored at 16, 23, and 33 d post-inoculation (DPI) using a 1 to 9 scale. There were highly significant differences between SM and its interaction with years. The CSM and IFL were the most consistent and highly correlated (r > 0.70, P < 0.01). Interspecific breeding line VCW 54 consistently had the highest WM resistance across years, SM, and evaluation dates, followed by A 195. White mold scores increased with delayed evaluations. Thus, CSM or IFL with disease assessed 33 DPI should be used for identifying common bean genotypes with high levels of physiological resistance to WM.Key words: Common bean, growth habit, race Mesoamerica, race Nueva Granada, Phaseolus vulgaris, Sclerotinia sclerotiorum


1992 ◽  
Vol 117 (2) ◽  
pp. 321-327 ◽  
Author(s):  
P.N. Miklas ◽  
K.F. Grafton ◽  
B.D. Nelson

A laboratory procedure was tested to determine whether excised stems would allow a reliable indication of partial physiological resistance (PPR) to white mold [Sclerotinia sclerotiorum (Lib.) deBary] in dry bean (Phaseolus vulgaris L.). Excised stems from 11- and 28-day-old plants were inoculated with growing mycelium of S. sclerotiorum, incubated for 4 to 7 days (11- and 28-day assays, respectively), then assayed for lesion length (LL). A total of 15 bean genotypes were screened for PPR, as indicated by LL. Significant (P < 0.05) differences among LL means of small- and medium-seeded bean genotypes were detected in the 28-day assay, whereas only LL means among medium-seeded genotypes. differed significantly (P < 0.05) in the n-day assay. `Bunsi', `C-20', `Sierra', `Topaz', and snap bean breeding lines NY 5262, NY 5394, and NY 5403 had the highest PPR and `Upland', D76125, and `UI-114' the lowest. The results from both assays were repeatable. A moderately high correlation (r = 0.68, P < 0.02) was observed between PPR and field resistance. The 28-day assay has potential for evaluating dry bean germplasm for PPR to white mold disease caused by S. sclerotiorum. A 28-day assay also was used to measure virulence of 18 isolates of S. sclerotiorum. The 18 isolates did not differ (P < 0.05) for virulence when measured by LL. The lack of any genotype × isolate interaction for LL indicated lack of host-pathogen specificity.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4152 ◽  
Author(s):  
Zhian N. Kamvar ◽  
B. Sajeewa Amaradasa ◽  
Rachana Jhala ◽  
Serena McCoy ◽  
James R. Steadman ◽  
...  

The ascomycete pathogen Sclerotinia sclerotiorum is a necrotrophic pathogen on over 400 known host plants, and is the causal agent of white mold on dry bean. Currently, there are no known cultivars of dry bean with complete resistance to white mold. For more than 20 years, bean breeders have been using white mold screening nurseries (wmn) with natural populations of S. sclerotiorum to screen new cultivars for resistance. It is thus important to know if the genetic diversity in populations of S. sclerotiorum within these nurseries (a) reflect the genetic diversity of the populations in the surrounding region and (b) are stable over time. Furthermore, previous studies have investigated the correlation between mycelial compatibility groups (MCG) and multilocus haplotypes (MLH), but none have formally tested these patterns. We genotyped 366 isolates of S. sclerotiorum from producer fields and wmn surveyed over 10 years in 2003–2012 representing 11 states in the United States of America, Australia, France, and Mexico at 11 microsatellite loci resulting in 165 MLHs. Populations were loosely structured over space and time based on analysis of molecular variance and discriminant analysis of principal components, but not by cultivar, aggressiveness, or field source. Of all the regions tested, only Mexico (n = 18) shared no MLHs with any other region. Using a bipartite network-based approach, we found no evidence that the MCGs accurately represent MLHs. Our study suggests that breeders should continue to test dry bean lines in several wmn across the United States to account for both the phenotypic and genotypic variation that exists across regions.


2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Eder Marques ◽  
Irene Martins ◽  
Mariana de Oliveira Cardoso Cunha ◽  
Marcello Arrais Lima ◽  
João Batista Tavares da Silva ◽  
...  

Abstract Forty-nine isolates of Trichoderma from the Brazilian Midwest were evaluated for their antagonistic activity in vitro against Sclerotinia sclerotiorum (causal agent of white mold), which were then identified based on their nuclear ribosomal ITS sequences. Paired culture tests showed that all isolates exhibited some antagonism, with a maximum of 77% mycelial inhibition and complete inhibition of sclerotia production. Two isolates were found to be the most promising biocontrol agents, considering both antagonistic parameters (CEN1253 - T. koningiopsis and CEN1265 - T. brevicompactum). Five different species were identified: T. harzianum (23), T. spirale (9), T. koningiopsis (8), T. brevicompactum (7) and T. asperellum (2). These isolates are stored in the Embrapa Fungi Collection for Biological Control and the information obtained in the experiments will be incorporated into the database of biological assets within the genetic resources information system (Allele) and be made available for further studies.


Plant Disease ◽  
2011 ◽  
Vol 95 (11) ◽  
pp. 1370-1377 ◽  
Author(s):  
Lindsey Otto-Hanson ◽  
James R. Steadman ◽  
Rebecca Higgins ◽  
Kent M. Eskridge

There is no complete resistance to Sclerotinia sclerotiorum, cause of white mold in dry bean (Phaseolus vulgaris). Variable resistance expression is one problem in screening for improved white mold resistance. With no previous information in the literature, pathogen variation in multisite screening nurseries was evaluated as one cause of diverse resistance expression. In all, 10 isolates of S. sclerotiorum used in greenhouse screening and 146 isolates collected from nine white mold field screening nurseries in major bean production areas in the United States were compared using mycelial compatibility groupings (MCGs) and an aggressiveness test. These 10 greenhouse screening isolates formed six MCGs. Among 156 field and greenhouse isolates, 64 MCGs were identified and 36 of those were each composed of a single unique isolate. Significant differences in isolate aggressiveness were found between some isolates in different MCGs but the isolates within an MCG did not differ in aggressiveness. High isolate variation found within and between field locations could influence the disease phenotype of putative white mold resistant germplasm. We next compared genotype and phenotype of isolates from screening nurseries and those from producer fields. Variability found in and among screening locations did reflect variability found in the four producer fields sampled. White mold resistance screening can be improved by knowledge of isolate genotypic and phenotypic characteristics.


2017 ◽  
Author(s):  
Zhian N Kamvar ◽  
Bimal S Amaradasa ◽  
Rachana Jhala ◽  
Serena McCoy ◽  
James R Steadman ◽  
...  

The ascomycete pathogen Sclerotinia sclerotiorum is a necrotrophic pathogen on over 400 known host plants, and is the causal agent of white mold on dry bean. Currently, there are no known cultivars of dry bean with complete resistance to white mold. For more than 20 years, bean breeders have been using white mold screening nurseries with natural populations of S. sclerotiorum to screen new cultivars for resistance. It is thus important to know if the genetic diversity in populations of S. sclerotiorum within these nurseries a) reflect the genetic diversity of the populations in the surrounding region and b) are stable over time. Furthermore, previous studies have investigated the correlation between mycelial compatibility groups (MCG) and multilocus haplotypes (MLH), but none have formally tested these patterns. We genotyped 366 isolates of S. sclerotiorum from producer fields and white mold screening nurseries surveyed over 10 years in 2003–2012 representing 11 states in the United States of America, Australia, France, and Mexico at 11 microsatellite loci resulting in 165 MLHs. Populations were loosely structured over space and time based on analysis of molecular variance and discriminant analysis of principal components, but not by cultivar, aggressiveness, or field source. Of all the regions tested, only Mexico (n=18) shared no MLHs with any other region. Using a bipartite network-based approach, we found no evidence that the MCGs accurately represent MLHs. Our study suggests that breeders should continue to test dry bean lines in several white mold screening nurseries across the US to account for both the phenotypic and genotypic variation that exists across regions.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Doha A. S. Gebily ◽  
Gamal A. M. Ghanem ◽  
Mona M. Ragab ◽  
Ayat M. Ali ◽  
Nour El-din K. Soliman ◽  
...  

Abstract Background White mold disease, caused by Sclerotinia sclerotiorum the devastating pathogen, attacks green beans (Phaseolus vulgaris L.) and several crops worldwide. The present investigation was carried out to introduce some antagonistic microorganisms as novel antifungal substances to be an alternative and secure method to effectively control the disease. Results Three Streptomyces species, i.e., S. griseus (MT210913 “DG5”), S. rochei (MN700192 “DG4”), and S. sampsonii (MN700191 “DG1”) were isolated, biologically, molecularly characterized, and evaluated in vitro and in vivo. Molecularly, polymerase chain reaction (PCR) amplification and nucleotide sequencing were used to characterize the pathogen and bio-agents. PCR amplification of the pathogen and Streptomyces species (bioagents) exhibited amplicons of around 535 bp and 1300 bp, respectively. The nucleotide sequence analysis of the three Streptomyces spp. indicated that S. rochei was closely related to S. griseus, and both had a distance relationship with S. sampsonii. The evaluation of bioagents was carried out against S. sclerotiorum. Reduction percentages in the mycelial growth of the pathogen ranged between 60.17 and 52.30%, indicating that S. rochie gave the highest inhibition percent. Incorporations of Streptomyces spp. culture filtrate components into culture media proved that S. sampsonii was more efficient as a bioagent in reducing mycelial growth pathogen by 84.50%. The effectiveness of the bioagent volatile compounds inhibited the pathogen growth at a rate of 54.50-72.54%, respectively, revealing that S. rochei was the highest inhibitor followed by S. griseus. The parasitic activity of Streptomyces spp. upon S. sclerotiorum showed deformation, contraction, and collapse when observed by light and scanning electron microscopy. Molecular characterization of the 3 Streptomyces spp. revealed that S. griseus was closely related to S. sampsonii (96%), secondly ranked by S. rochei (93.1%). Viability and germination of pathogen sclerotia were reduced when they dipped into the Streptomyces spore suspensions for 10, 20, and 30 days. Application of the 3 Streptomyces spp. in the field proved a great potential to control the disease. Conclusions The results suggested that the 3 Streptomyces strains and their secondary metabolites can be potential biocontrol agents and biofertilizers for controlling S. sclerotiorum, the causative agent of bean white mold disease.


2017 ◽  
Author(s):  
Zhian N Kamvar ◽  
Bimal S Amaradasa ◽  
Rachana Jhala ◽  
Serena McCoy ◽  
James R Steadman ◽  
...  

The ascomycete pathogen Sclerotinia sclerotiorum is a necrotrophic pathogen on over 400 known host plants, and is the causal agent of white mold on dry bean. Currently, there are no known cultivars of dry bean with complete resistance to white mold. For more than 20 years, bean breeders have been using white mold screening nurseries with natural populations of S. sclerotiorum to screen new cultivars for resistance. It is thus important to know if the genetic diversity in populations of S. sclerotiorum within these nurseries a) reflect the genetic diversity of the populations in the surrounding region and b) are stable over time. Furthermore, previous studies have investigated the correlation between mycelial compatibility groups (MCG) and multilocus haplotypes (MLH), but none have formally tested these patterns. We genotyped 366 isolates of S. sclerotiorum from producer fields and white mold screening nurseries surveyed over 10 years in 2003–2012 representing 11 states, Mexico, France, and Australia at 11 microsatellite loci resulting in 165 MLHs. Populations were loosely structured over space and time based on analysis of molecular variance and discriminant analysis of principal components, but not by cultivar, aggressiveness, or field source. Of all the regions tested, only Mexico (n=18) shared no MLHs with any other region. Using a bipartite network-based approach, we found no evidence that the MCGs accurately represent MLHs. Our study suggests that breeders should continue to test dry bean lines in several white mold screening nurseries across the US to account for both the phenotypic and genotypic variation that exists across regions.


2017 ◽  
Author(s):  
Zhian N Kamvar ◽  
Bimal S Amaradasa ◽  
Rachana Jhala ◽  
Serena McCoy ◽  
James R Steadman ◽  
...  

The ascomycete pathogen Sclerotinia sclerotiorum is a necrotrophic pathogen on over 400 known host plants, and is the causal agent of white mold on dry bean. Currently, there are no known cultivars of dry bean with complete resistance to white mold. For more than 20 years, bean breeders have been using white mold screening nurseries with natural populations of S. sclerotiorum to screen new cultivars for resistance. It is thus important to know if the genetic diversity in populations of S. sclerotiorum within these nurseries a) reflect the genetic diversity of the populations in the surrounding region and b) are stable over time. Furthermore, previous studies have investigated the correlation between mycelial compatibility groups (MCG) and multilocus haplotypes (MLH), but none have formally tested these patterns. We genotyped 366 isolates of S. sclerotiorum from producer fields and white mold screening nurseries surveyed over 10 years in 2003–2012 representing 11 states in the United States of America, Australia, France, and Mexico at 11 microsatellite loci resulting in 165 MLHs. Populations were loosely structured over space and time based on analysis of molecular variance and discriminant analysis of principal components, but not by cultivar, aggressiveness, or field source. Of all the regions tested, only Mexico (n=18) shared no MLHs with any other region. Using a bipartite network-based approach, we found no evidence that the MCGs accurately represent MLHs. Our study suggests that breeders should continue to test dry bean lines in several white mold screening nurseries across the US to account for both the phenotypic and genotypic variation that exists across regions.


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