STUDIES ON BIOLOGICAL CONTROL OF FIRE BLIGHT WITH SOME ANTAGONISTIC BACTERIA

2006 ◽  
pp. 337-340
Author(s):  
H. Özaktan ◽  
T. Bora
Keyword(s):  
Biological Control ◽  
Fire Blight ◽  
Antagonistic Bacteria

scholarly journals Influence of Age of Apple Flowers on Growth of Erwinia amylovora and Biological Control Agents

Plant Disease ◽  
2003 ◽  
Vol 87 (5) ◽  
pp. 502-509 ◽  
Author(s):  
S. V. Thomson ◽  
S. C. Gouk
Keyword(s):  
Biological Control ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Antagonistic Bacteria ◽  
Biological Control Agents ◽  
Limited Growth ◽  
Bacterial Populations ◽  
Arid Conditions ◽  
Flower Age ◽  
Causal Pathogen

The influence of flower age on growth of Erwinia amylovora, the causal pathogen of fire blight of apples and pears, was investigated under humid and arid conditions in Hamilton, New Zealand (NZ), and Logan, UT, USA, respectively. ‘Royal Gala’ apple flowers ranging from 1 to 8 days old were atomized with E. amylovora. Pistils were dissected and washed separately from the remaining floral parts (flowers ex pistils) for estimation of bacterial numbers. Pistils, 1 to 3 days old (USA) and 1 to 4 days old (NZ), supported exponential growth of E. amylovora, but bacterial populations did not increase when older flowers were inoculated. Scanning electron microscopy showed round and turgid papillae on stigmas of 1-day-old flowers. Papillae on 4- to 6-day-old stigmas were completely collapsed and covered in mucilage. Populations of E. amy-lovora on the flowers ex pistils were characteristically lower than pistil populations. High populations of saprophytic bacteria were found on both floral parts of all ages, but there was no difference in their numbers on 3- to 6-day-old pistils. This suggests their presence did not inhibit the growth of E. amylovora on older stigmas. The results demonstrate that stigmas on 1- to 3-day-old flowers often support rapid growth of E. amylovora, but flowers inoculated when more than 4 to 5 days old do not support growth or only limited growth. The same location and pattern of bacterial growth occurred with the biological control agents Pseudomonas fluorescens PfA506n and Pantoea agglomerans (Erwinia herbicola) Eh318nr. The distinct effect of flower age on growth of antagonistic bacteria and E. amylovora may be important in deciding when to treat with biological control organisms or bactericides.

scholarly journals Field Evaluation of Biological Control of Fire Blight in the Eastern United States

Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 386-394 ◽  
Author(s):  
George W. Sundin ◽  
Nicole A. Werner ◽  
Keith S. Yoder ◽  
Herb S. Aldwinckle
Keyword(s):  
United States ◽  
New York ◽  
Biological Control ◽  
Fire Blight ◽  
Field Evaluation ◽  
Pantoea Agglomerans ◽  
Eastern United States ◽  
Bacterial Antagonists ◽  
Bacterial Endospores ◽  
Control Options

The bacterial antagonists Pseudomonas fluorescens A506, Pantoea agglomerans C9-1, and Pantoea agglomerans E325 and preparations of Bacillus subtilis QST 713 containing bacterial endospores and lipopeptide metabolites were evaluated for efficacy in controlling fire blight in Michigan, New York, and Virginia. When examined individually, the biological control materials were not consistently effective in reducing blossom infection. The average reduction in blossom infection observed in experiments conducted between 2001 and 2007 was variable and ranged from 9.1 to 36.1%, while control with streptomycin was consistent and ranged from 59.0 to 67.3%. Incidence of blossom colonization by the bacterial antagonists was inconsistent, and <60% of stigmata had the antagonists present in 12 of 25 experiments. Consistent control of blossom infection was observed when the biological control materials were integrated into programs with streptomycin, resulting in a reduction of the number of streptomycin applications needed to yield similar levels of control. Our results indicate that the prospects for biological control of fire blight in the eastern United States are currently not high due to the variability in efficacy of existing biological control options.

scholarly journals Mechanistically Compatible Mixtures of Bacterial Antagonists Improve Biological Control of Fire Blight of Pear

2011 ◽  
Vol 101 (1) ◽  
pp. 113-123 ◽  
Author(s):  
V. O. Stockwell ◽  
K. B. Johnson ◽  
D. Sugar ◽  
J. E. Loper
Keyword(s):  
Biological Control ◽  
Plant Disease ◽  
Fire Blight ◽  
Biological Control Agent ◽  
Field Trials ◽  
Control Agent ◽  
Extracellular Protease ◽  
Peptide Antibiotics ◽  
Biological Control Agents ◽  
Control Activity

Mixtures of biological control agents can be superior to individual agents in suppressing plant disease, providing enhanced efficacy and reliability from field to field relative to single biocontrol strains. Nonetheless, the efficacy of combinations of Pseudomonas fluorescens A506, a commercial biological control agent for fire blight of pear, and Pantoea vagans strain C9-1 or Pantoea agglomerans strain Eh252 rarely exceeds that of individual strains. A506 suppresses growth of the pathogen on floral colonization and infection sites through preemptive exclusion. C9-1 and Eh252 produce peptide antibiotics that contribute to disease control. In culture, A506 produces an extracellular protease that degrades the peptide antibiotics of C9-1 and Eh252. We hypothesized that strain A506 diminishes the biological control activity of C9-1 and Eh252, thereby reducing the efficacy of biocontrol mixtures. This hypothesis was tested in five replicated field trials comparing biological control of fire blight using strain A506 and A506 aprX::Tn5, an extracellular protease-deficient mutant, as individuals and combined with C9-1 or Eh252. On average, mixtures containing A506 aprX::Tn5 were superior to those containing the wild-type strain, confirming that the extracellular protease of A506 diminished the biological control activity of C9-1 and Eh252 in situ. Mixtures of A506 aprX::Tn5 and C9-1 or Eh252 were superior to oxytetracycline or single biocontrol strains in suppressing fire blight of pear. These experiments demonstrate that certain biological control agents are mechanistically incompatible, in that one strain interferes with the mechanism by which a second strain suppresses plant disease. Mixtures composed of mechanistically compatible strains of biological control agents can suppress disease more effectively than individual biological control agents.

scholarly journals Isolation, Characterization, and Identification of Biological Control Agent for Potato Soft Rot in Bangladesh

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
M. M. Rahman ◽  
M. E. Ali ◽  
A. A. Khan ◽  
A. M. Akanda ◽  
Md. Kamal Uddin ◽  
...  
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Control Agent ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Antagonistic Bacteria ◽  
And Storage

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacteriumErwinia carotovorasubsp.carotovora(Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was testedin vitroagainst the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited thein vitrogrowth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genusBacillusand the isolate E-45 asLactobacillussp. The stronger antagonistic activity against Ecc P-138 was found in E-65in vitroscreening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.

scholarly journals Biological Control of Chickpea Collar Rot by Co-inoculation of Antagonistic Bacteria and Compatible Rhizobia

2010 ◽  
Vol 50 (4) ◽  
pp. 419-424 ◽  
Author(s):  
B. Hameeda ◽  
G. Harini ◽  
O. P. Rupela ◽  
J. V. D. K. Kumar Rao ◽  
Gopal Reddy
Keyword(s):  
Biological Control ◽  
Antagonistic Bacteria ◽  
Collar Rot
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