scholarly journals Field trials with non-bactericide products to control fire blight in apple orchards

2004 ◽  
Vol 10 (2) ◽  
Author(s):  
T. Bubán ◽  
P. Sallai ◽  
J. Deme
Keyword(s):  
Active Ingredient ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Field Trials ◽  
The Other ◽  
European Countries ◽  
Nutrient Elements ◽  
Chemical Agents ◽  
Shoot Blight ◽  
In Fire

Recently, novel strategies and chemical agents for prophylactic protection against the bacterial (Erwinia amylovora) disease fire blight are being sought. Resistance-inducing compounds, such as prohexadione-Ca represent promising alternatives. Prohexadione-Ca is the active ingredient of the bioregulator Regalis, currently being introduced in several European countries and overseas. Another product used in this study was Biomit Plussz, a leaf fertiliser providing harmonic supply of nutrient elements, the complete supply is assumed to improve the tolerance against diseases. Treatments' effects of both of these products were compared to the effectiveness of treatments with antibiotics repeated twice, three or four times a season. In the years of 2001 and 2002, the effectiveness of both Regalis and Biomit Plussz in reduction of incidence of shoot blight was similar, or proved to be superior to the check treatments consisting of repeated sprayings of antibiotics. Last year (2003) treatments of streptomycin resulted — although within the same magnitude — in a somewhat better control of shoot blight than sprayings with the other compounds. As regards severity of blossom blight, inconsistent results were recorded concerning both Regalis and Biomit Plussz. In general, prohexadione-Ca is less efficient for controlling flower infection by E. amylovora as compared to shoot infections, since successful prophylactic treatments are difficult to carry out early in the season. The highest effectiveness in fire blight management can, therefore, be achieved by using prohexadione-Ca (as preventive protection) in combination with streptomycin or other suitable antibiotics (as curative protection).

Clarifying the Roles of White Apple Leafhopper and Potato Leafhopper (Homoptera: Cicadellidae) in Fire Blight Transmission in Apple

1999 ◽  
Vol 34 (3) ◽  
pp. 314-321 ◽  
Author(s):  
D. G. Pfeiffer ◽  
J. C. Killian ◽  
K. S. Yoder
Keyword(s):  
Significant Role ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Vascular Tissue ◽  
The Other ◽  
Potato Leafhopper ◽  
Factorial Experiments ◽  
Causal Organism ◽  
In Fire ◽  
Growing Shoot

White apple leafhopper, Typhlocyba pomaria McAtee, and potato leafhopper, Empoasca fabae (Harris), were evaluated for their potential to incite fire blight infection in apple in the presence of the causal organism, Erwinia amylovora (Burrill) Winslow et al. Each leafhopper species was used as one factor in a series of 2 × 2 factorial experiments; the other factor was the presence or absence of E. amylovora. There was no evidence for a role for white apple leafhopper which feeds in the mesophyll of middle-aged and older leaves. There was sometimes a significant role for potato leafhopper which feeds in the vascular tissue of growing shoot tips.

scholarly journals Sensitivity of Erwinia amylovora in Illinois Apple Orchards to Streptomycin, Oxytetracyline, Kasugamycin, and Copper

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1484-1490 ◽  
Author(s):  
A. G. Jurgens ◽  
M. Babadoost
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Field Trials ◽  
Luria Bertani ◽  
Apple Orchard ◽  
Streptomycin Resistance ◽  
Colony Development ◽  
Apple Orchards ◽  
Shoot Blight ◽  
Prohexadione Calcium

In 2008 and 2009, severe fire blight (Erwinia amylovora) occurred in Illinois apple orchards, leading to speculation that streptomycin-resistant strains of E. amylovora might be present in some orchards. Statewide surveys were conducted in 2010, 2011, and 2012, and 117, 129, and 170, E. amylovora isolates were collected, respectively, from 20 counties. None of the 416 E. amylovora isolates tested were resistant to streptomycin (Agri-Mycin 17WP) at 50 mg/liter. Seven non-E. amylovora bacterial isolates were collected from E. amylovora-infected shoots that contained both a strA-strB streptomycin resistance gene and IS1133 on transposon Tn5393, which could be a potential source of streptomycin resistance for E. amylovora in Illinois in the future. Colony development of all 84 E. amylovora isolates tested was inhibited on Luria-Bertani medium amended with oxytetracycline at 50 mg/liter and kasugamycin (Kasumin 2L) at 100 mg/liter. Similarly, colony development of the 84 E. amylovora isolates was inhibited on casitone-yeast extract medium amended with copper sulfate at 0.16 mM. In 2011 and 2012, field trials were conducted to evaluate the efficacy of oxytetracycline (Mycoshield 17WP), kasugamycin (Kasumin 2L and ARY-4016-06), copper hydroxide (Kocide-3000 41.6DF), Bacillus subtilis (Serenade Max, QST713), and Pseudomonas fluorescens (Blight Ban A506) for management of fire blight in an apple orchard. Only kasugamycin (Kasumin 2L and ARY-4016-06) reduced blossom infection significantly. There was a significant interaction of kasugamycin (Kasumin 2L) with prohexadione calcium (Apogee 27.5DF) in reducing shoot blight incidence in the field in 2012.

MECHANISMS INVOLVED IN FIRE BLIGHT PROTECTION OF APPLE WITH AN HRPL MUTANT OF ERWINIA AMYLOVORA

2006 ◽  
pp. 481-482
Author(s):  
M. Faize ◽  
M.N. Brisset ◽  
J.P. Paulin ◽  
M. Tharaud ◽  
C. Perino ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
In Fire

scholarly journals Control of Fire Blight by Pseudomonas fluorescens A506 and Pantoea vagans C9-1 Applied as Single Strains and Mixed Inocula

2010 ◽  
Vol 100 (12) ◽  
pp. 1330-1339 ◽  
Author(s):  
V. O. Stockwell ◽  
K. B. Johnson ◽  
D. Sugar ◽  
J. E. Loper
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Field Trials ◽  
Disease Suppression ◽  
Biological Control Agents ◽  
Population Sizes ◽  
Mixed Inocula ◽  
Pantoea Vagans

The biological control agents Pseudomonas fluorescens A506 and Pantoea vagans C9-1 were evaluated individually and in combination for the suppression of fire blight of pear or apple in 10 field trials inoculated with the pathogen Erwinia amylovora. The formulation of pathogen inoculum applied to blossoms influenced establishment of the pathogen and the efficacy of biological control. Pantoea vagans C9-1 suppressed fire blight in all five trials in which the pathogen was applied as lyophilized cells but in none of the trials in which the pathogen was applied as freshly harvested cells. In contrast, Pseudomonas fluorescens A506 reduced disease significantly in only one trial. A mixture of the two strains also suppressed fire blight, but the magnitude of disease suppression over all field trials (averaging 32%) was less than that attained by C9-1 alone (42%). The two biological control agents did not antagonize one another on blossom surfaces, and application of the mixture of A506 and C9-1 to blossoms resulted in a greater proportion of flowers having detectable populations of at least one bacterial antagonist than the application of individual strains. Therefore, the mixture of A506 and C9-1 provided less disease control than expected based upon the epiphytic population sizes of the antagonists on blossom surfaces. We speculate that the biocontrol mixture was less effective than anticipated due to incompatibility between the mechanisms by which A506 and C9-1 suppress disease.

scholarly journals Susceptibility of some traditional pear cultivars of Hungarian and foreign origin to the pathogenic bacterium Erwinia amylovora

2004 ◽  
Vol 10 (3) ◽  
Author(s):  
K. Honty ◽  
M. Hevesi ◽  
M. Göndör ◽  
G. Tóth M. ◽  
V. Bács-Várkuti ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Control Measure ◽  
Unknown Origin ◽  
The Other ◽  
High Susceptibility ◽  
Resistant Cultivars ◽  
Susceptibility To Infection ◽  
Prospective Control ◽  
Complete Resistance

Fire blight, a disease caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., has been causing serious damage in Hungarian pear plantations since 1996. A prospective control measure could be the use of resistant cultivars. For that purpose ten pear cultivars have been tested under laboratory and greenhouse conditions for resistance to Erwinia amylovora strains collected in Hungary. Six of these cultivars are Hungarian ones of unknown origin, while four are traditional old varieties. Resistant cultivars should serve as germplasm for future breeding. Inoculations were made with a mixture of different pear isolates of the bacteria collected from various growing regions of Hungary (Ea 21, 23), at a density of 5x108 cells/ml. Susceptibility/resistance has been assessed on the basis of intensity of blight symptoms observed on shoots, flower parts and fruits. Cultivars were assigned to three susceptibility groups (low, moderate and high). Complete resistance was not found among the cultivars tested. The highest level of resistance was found in cultivar 'Kieffer', while the other cultivars displayed either moderate or high susceptibility to infection.

scholarly journals Prevalence of Streptomycin-Resistant Erwinia amylovora in New York Apple Orchards

Plant Disease ◽  
2016 ◽  
Vol 100 (4) ◽  
pp. 802-809 ◽  
Author(s):  
K. A. Tancos ◽  
S. Villani ◽  
S. Kuehne ◽  
E. Borejsza-Wysocka ◽  
D. Breth ◽  
...  
Keyword(s):  
United States ◽  
New York ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
The United States ◽  
Streptomycin Resistance ◽  
Apple Orchards ◽  
Wayne County ◽  
The Past ◽  
Shoot Blight

Resistance to streptomycin in Erwinia amylovora was first observed in the United States in the 1970s but was not found in New York until 2002, when streptomycin-resistant (SmR) E. amylovora was isolated from orchards in Wayne County. From 2011 to 2014, in total, 591 fire blight samples representing shoot blight, blossom blight, and rootstock blight were collected from 80 apple orchards in New York. From these samples, 1,280 isolates of E. amylovora were obtained and assessed for streptomycin resistance. In all, 34 SmR E. amylovora isolates were obtained from 19 individual commercial orchards. The majority of the resistant isolates were collected from orchards in Wayne County, and the remaining were from other counties in western New York. Of the 34 resistant isolates, 32 contained the streptomycin resistance gene pair strA/strB in the transposon Tn5393 on the nonconjugative plasmid pEA29. This determinant of streptomycin resistance has only been found in SmR E. amylovora isolates from Michigan and the SmR E. amylovora isolates discovered in Wayne County, NY in 2002. Currently, our data indicate that SmR E. amylovora is restricted to counties in western New York and is concentrated in the county with the original outbreak. Because the resistance is primarily present on the nonconjugative plasmid, it is possible that SmR has been present in Wayne County since the introduction in 2002, and has spread within and out of Wayne County to additional commercial growers over the past decade. However, research is still needed to provide in-depth understanding of the origin and spread of the newly discovered SmR E. amylovora to reduce the spread of streptomycin resistance into other apple-growing regions, and address the sustainability of streptomycin use for fire blight management in New York.

scholarly journals Establishment of Bacterial Antagonists of Erwinia amylovora on Pear and Apple Blossoms as Influenced by Inoculum Preparation

1998 ◽  
Vol 88 (6) ◽  
pp. 506-513 ◽  
Author(s):  
V. O. Stockwell ◽  
K. B. Johnson ◽  
J. E. Loper
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Culture Media ◽  
Field Trials ◽  
Bacterial Cells ◽  
Fluorescent Microspheres ◽  
Bacterial Antagonists ◽  
Spray Inoculation ◽  
Population Sizes ◽  
Inoculum Preparation

The influence of inoculum preparation on the establishment of bacterial antagonists that suppress fire blight and Erwinia amylovora on blossoms was evaluated. Aqueous suspensions of Pseudomonas fluorescens A506, E. herbicola C9-1R, or E. amylovora 153N were prepared from cells harvested from the surface of an agar medium or from cells that were lyophilized after culture under similar conditions. Bacterial suspensions (1 × 108 CFU/ml) were sprayed on pear and apple trees at 50% bloom near midday. The incidence of recovery (proportion of blossoms containing detectable populations) and the population sizes of the bacteria on individual blossoms with detectable populations were followed over a period of several days. Fluorescent microspheres (1 μm in diameter) were added to sprays at a concentration of 1 × 107 microspheres per ml to mark blossoms that were open during application of bacteria. After dilution-plating, the stigmas and styles of each blossom were examined for the presence of microspheres with an epifluorescence microscope. In three of five trials, bacteria applied as suspensions of lyophilized cells were recovered from a greater proportion of blossoms than bacterial cells harvested directly from culture media. Every blossom harvested within 6 days after spraying had microspheres present on the surfaces of the styles and stigmas; thus, lack of establishment of detectable populations, rather than escape of blossoms from spray inoculation, accounted for the differences in proportion of blossoms colonized by the different preparations of bacteria. The use of lyophilized cells in field trials decreased variability in the establishment of bacteria on blossoms.

EFFICACY OF TRANSMISSION OF FIRE BLIGHT RESISTANCE IN PYRUS

1968 ◽  
Vol 48 (3) ◽  
pp. 231-243 ◽  
Author(s):  
R. E. C. Layne ◽  
Catherine H. Bailey ◽  
L. F. Hough
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Common Species ◽  
The Other ◽  
Breeding Value ◽  
Screening Procedure ◽  
Blight Resistance ◽  
Quantitative Inheritance ◽  
Segregation Data

An efficient, reproducible seedling-screening procedure was devised that gave almost 100% infection yet differential levels of resistance to Erwinia amylovora. Seedling segregation for resistance to fire blight was studied for 48 separate progenies with segregation data based on 7,462 seedlings. Sources of high, intermediate or low resistance derived from P. ussuriensis, P. serotina or P. communis were compared for ability to transmit resistance to their offspring. P. communis selections that were most efficient in transmitting resistance to their progeny included: Magness, Purdue 80-51, Maxine and Mich. US 437. Similarly, the most efficient sources in the P. ussuriensis group included: Purdue 77-73, NJ 484338262 and NJ 487601174; and the most efficient in the P. serotina group included: Purdue 110-9 and Kieffer. The breeding value of the most efficient P. communis sources was considered to be superior to the other two species sources in view of the larger size and higher quality of fruit associated with P. communis.Continuous distributions rather than discontinuous segregation were obtained with most progenies, regardless of species source or level of resistance. Some distributions were similar to those associated with quantitative inheritance, others were more representative of qualitative inheritance, with dominance of resistance in each case. No consistent type of segregation distribution characterized progenies having a common species source of resistance.

Some observations on the physiology of Erwinia herbicola and its possible implication as a factor antagonistic to Erwinia amylovora in the "fire-blight" syndrome

1969 ◽  
Vol 15 (6) ◽  
pp. 641-642 ◽  
Author(s):  
A. K. Chatterjee ◽  
L. N. Gibbins ◽  
J. A. Carpenter
Keyword(s):  
Oxidative Metabolism ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Erwinia Herbicola ◽  
In Fire

Erwinia herbicola, which is often associated with E. amylovora in "fire-blight" diseased tissues, possesses a β-glucosidase which cleaves arbutin to yield hydroquinone and D-glucose. Hydroquinone accumulated in cultures of E. herbicola grown on arbutin broth to a concentration of ca. 1000 μg/ml after 24 hours. Accumulation of hydroquinone occurred to a much lesser extent in E. amylovora cultures. Hydroquinone inhibited the oxidative metabolism of D-glucose by E. amylovora, but not by E. herbicola. The implication of these observations to the development of the "fire-blight" syndrome is discussed.

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