CHAPTER 19: Fire in the Orchard: Insights into Fire Blight Disease and Its Causal Agent, Erwinia amylovora

2016 ◽  
pp. 347-364
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Causal Agent ◽  
Blight Disease

scholarly journals Isolation and efficacy of two bacterial strains antagonists of Erwinia amylovora and Pectobacterium carotovorum

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
M’hamed BENADA ◽  
Boualem BOUMAAZA ◽  
Sofiane BOUDALIA ◽  
Omar KHALADI
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Species ◽  
Crop Protection ◽  
Soft Rot ◽  
Causal Agent ◽  
Plant Diseases ◽  
Ecological Niches ◽  
Pectobacterium Carotovorum ◽  
Bacterial Strains

Abstract Background The development of ecofriendly tools against plant diseases is an important issue in crop protection. Screening and selection process of bacterial strains antagonists of 2 pathogenic bacterial species that limit very important crops, Erwinia amylovora, the causal agent of the fire blight disease, and Pectobacterium carotovorum, the causal agent of bacterial potato soft rot, were reported. Bacterial colonies were isolated from different ecological niches, where both pathogens were found: rhizosphere of potato tubers and fruits and leaves of pear trees from the northwest region of Algeria. Direct and indirect confrontation tests against strains of E. amylovora and P. carotovorum were performed. Results Results showed a significant antagonistic activity against both phytopathogenic species, using direct confrontation method and supernatants of cultures (p<0.005). In vitro assays showed growth inhibitions of both phytopathogenic species. Furthermore, results revealed that the strains of S. plymuthica had a better inhibitory effect than the strains of P. fluorescens against both pathogens. In vivo results on immature pear fruits showed a significant decrease in the progression of the fire blight symptoms, with a variation in the infection index from one antagonistic strain to another between 31.3 and 50%, and slice of potato showed total inhibition of the pathogen (P. carotovorum) by the antagonistic strains of Serratia plymuthica (p<0.005). Conclusion This study highlighted that the effective bacteria did not show any infection signs towards plant tissue, and considered as a potential strategy to limit the fire blight and soft rot diseases.

scholarly journals Fire Blight Symptomatic Shoots and the Presence of Erwinia amylovora in Asymptomatic Apple Budwood

Plant Disease ◽  
2017 ◽  
Vol 101 (1) ◽  
pp. 186-191 ◽  
Author(s):  
K. A. Tancos ◽  
E. Borejsza-Wysocka ◽  
S. Kuehne ◽  
D. Breth ◽  
Kerik D. Cox
Keyword(s):  
New York ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Causal Agent ◽  
Economic Losses ◽  
Apple Trees ◽  
The Mean ◽  
Collection Practices ◽  
Time Of Collection ◽  
Young Apple

Erwinia amylovora, the causal agent of fire blight, causes considerable economic losses in young apple plantings in New York on a yearly basis. Nurseries make efforts to only use clean budwood for propagation, which is essential, but E. amylovora may be present in trees that appear to have no apparent fire blight symptoms at the time of collection. We hypothesized that the use of infected budwood, especially by commercial nursery operations, could be the cause, in part, of fire blight outbreaks that often occur in young apple plantings in New York. Our goal was to investigate the presence of E. amylovora in asymptomatic budwood from nursery source plantings as it relates to trees with fire blight symptoms. From 2012 to 2015, apple budwood was collected from two commercial budwood source plantings of ‘Gala’ and ‘Topaz’ at increasing distances from visually symptomatic trees. From these collections, internal contents of apple buds were analyzed for the presence of E. amylovora. E. amylovora was detected in asymptomatic budwood in trees more than 20 m from trees with fire blight symptoms. In some seasons, there were significant (P ≤ 0.05) differences in the incidence of E. amylovora in asymptomatic budwood collected from symptomatic trees and those up to 20 m from them. In 2014 and 2015, the mean E. amylovora CFU per gram recovered from budwood in both the Gala and Topaz plantings were significantly lower in budwood collected 20 m from symptomatic trees. Further investigation of individual bud dissections revealed that E. amylovora was within the tissue beneath the bud scales containing the meristem. Results from the study highlight the shortcomings of current budwood collection practices and the need to better understand the factors that lead to the presence of E. amylovora in bud tissues to ensure the production of pathogen-free apple trees.

scholarly journals Evaluation of Susceptibility of Different Pear Hybrid Populations to Fire Blight (Erwinia amylovora)

2011 ◽  
Vol 39 (1) ◽  
pp. 226 ◽  
Author(s):  
Yasemin EVRENOSOĞLU ◽  
Adalet MISIRLI ◽  
Hikmet SAYGILI ◽  
Emre BİLEN ◽  
Özlem BOZTEPE ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Open Pollination ◽  
Resistance Level ◽  
Class A ◽  
Class B ◽  
Artificial Inoculations ◽  
Serious Disease ◽  
Blight Disease ◽  
Santa Maria

Fire blight disease caused by pathogenic bacterium Erwinia amylovora, is the serious disease of pear, and there is not a certain chemical management against this disease except antibiotic-type compounds such as streptomycin. It is very important to improve new fire blight resistant cultivars in case of integrated disease management. With this purpose, different crosses have been made between Pyrus communis varieties that have good fruit characteristics and resistant cultigens. Besides, self and open pollination treatments have been carried out in maternal plants. The disease resistance level of the hybrids obtained from these combinations was determined by artificial inoculations by Erwinia amylovora in greenhouse conditions. A total of 3284 hybrids were inoculated, and 2631 of them survived and were distributed to different susceptibility classes. 19.88% of the inoculated hybrids was killed by Erwinia amylovora. Total distribution of the hybrids to susceptibility classes was as 6.18% in class “A- slightly susceptible”, 3.11% in class “B- less susceptible”, 8.89% in class “C- mid-susceptible”, 20.28% in class “D- susceptible”, and 61.54% in class “E- very susceptible”. Majority of class “A- slightly susceptible” hybrids were obtained from ‘Magness’ x ‘Ankara’ combination. ‘Kieffer’ x ‘Santa Maria’, ‘Kieffer’ open pollination, ‘Magness’ x ‘Akça’, ‘Magness’ x ‘Kieffer’, ‘Magness’ x ‘Santa Maria’, ‘Mustafa Bey’ x ‘Moonglow’ treatments displayed good results with respect to “A- slightly susceptible” character. It is very important to evaluate these hybrid pear populations through different fruit and tree characteristics in the future.

New potential bacterial antagonists for the biocontrol of fire blight disease (Erwinia amylovora) in Morocco

2018 ◽  
Vol 117 ◽  
pp. 7-15 ◽  
Author(s):  
Smail Ait Bahadou ◽  
Abderrahmane Ouijja ◽  
Abdelkarim Karfach ◽  
Abdessalem Tahiri ◽  
Rachid Lahlali
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Antagonists ◽  
Blight Disease

scholarly journals Reactions of different plant organs of pear cultivars to Erwinia amylovora infection

2003 ◽  
Vol 9 (1) ◽  
Author(s):  
K. Honty ◽  
Z. Boldog ◽  
M. Göndör ◽  
J. Papp ◽  
K. Kása ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Process Development ◽  
Disease Process ◽  
Research Project ◽  
Plant Organs ◽  
Blight Disease

Research project has been initiated in 1999 with the aim of evaluating the degree of susceptibility/resistance of pear cultivars grown in Hungary to fire blight disease caused by Erwinia amylovora. The recently selected promising cultivars were also examined. Inoculation experiments were conducted in controlled greenhouse conditions because of quarantine regulations in Hungary. Following the disease process, development of symptoms of plant organs (shoots, flower parts, fruits) was observed. Suspension of two E. amylovora strains (Ea 21, Ea 23) isolated from pear was used in a mixture (5x108 cells x m1-1) for the inoculation. Twenty-six pear cultivars were examined and grouped into four categories: low susceptibility, moderately susceptible, susceptible and very susceptible. Most of the cultivars were susceptible or very susceptible while some promising 'Eldorado', 'Harrow Delight' and `Hosui' showed low susceptibility.

scholarly journals Management of Erwinia amylovora by Potential Bio-Pesticides in vitro and in vivo Conditions

2020 ◽  
Vol 8 (sp1) ◽  
pp. 38-45
Author(s):  
Kubilay Kurtulus Bastas
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Shoot Length ◽  
Absolute Methanol ◽  
Diffusion Method ◽  
Thymus Vulgaris ◽  
Blight Disease ◽  
Santa Maria

Erwinia amylovora, the causative agent of fire blight disease, threatens a lot of species of the Rosaceae family. Antibiotics and copper compounds in chemical applications are most frequently are applied, but these can be phytotoxic and cause resistant strains of the pathogen. In our experiments, 20 herbal materials were tested for their antimicrobial effectiveness against the fire blight pathogen in vitro and in planta. The air-dried plants ground into fine powder and extraction was performed at room temperature by maceration with 80% (v/v) methanol/distilled water. The minimum inhibitory concentration values were determined by using disc diffusion method and streptomycin was used as control in all experiments. Antimicrobial activity was evaluated by measuring the inhibition zones in reference to the pathogen. Among the tested plants, Szygium aromaticum, Thymus vulgaris and Rhus cararia showed a good antibacterial activity and they inhibited the growth of E. amylovora with inhibition zone diameter ranging from 21 to 27 mm at 20% (w/v) in absolute methanol compared to streptomycin (31 mm) in vitro conditions. In vivo tests were performed by using highly virulent E. amylovora isolate (Eak24b, 91%) grown on TSA medium and inoculation on young shoots of 3-year-old Gala variety of apple and Santa Maria variety of pear seedlings at 107 CFU ml-1 density of the pathogen. Disease severity (%) was assessed by by proportion of blighted shoot length to the whole shoot length and also efficacy of the extracts was determined by using Abbott formula. The highest efficacy was obtained by S. aromaticum and T. vulgaris extracts of reducing shoot blight of cv. Gala and cv. Santa Maria by 67.81% - 64-12% and 51.50% - 51.04% ratios, respectively. Obtaining results showed that some medicinal and aromatic plant extracts might be used against fire blight disease as potential new generation chemicals on pome fruits within integrated and organic control programs.

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