scholarly journals Resistance of Raspberry Cultivars to Fire Blight

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1189-1192 ◽  
Author(s):  
P.G. Braun ◽  
P.D. Hildebrand ◽  
A.R. Jamieson
Keyword(s):  
Disease Severity ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Rubus Idaeus ◽  
The Other ◽  
Lesion Length ◽  
Disease Development ◽  
Red Raspberry ◽  
Progress Curve ◽  
Wide Range

Twenty-five cultivars of red raspberry (Rubus idaeus L.) and one purple raspberry (R. occidentalis L. × R. idaeus L.) were evaluated for their resistance to fire blight caused by Erwinia amylovora (Burr.) Winslow et al. Actively growing raspberry cane tips were wound inoculated with three isolates of the pathogen and disease development was assessed over 17 days. Three methods of evaluating resistance were used: area under the disease progress curve (AUDPC), a weighted AUDPC called the area under the disease severity curve (AUDSC), and lesion length. A wide range of resistance levels was observed, but no cultivars were symptomless. Primocane-fruiting cultivars tended to be more resistant than floricane-fruiting ones. Of the three E. amylovora isolates used in this study, one was significantly more virulent than the other two, but no cultivar × isolate interaction was detected.

scholarly journals Resistance to Fire Blight among Flowering Pears and Quince

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 413-415 ◽  
Author(s):  
Andrew C. Bell ◽  
Thomas G. Ranney ◽  
Thomas A. Eaker ◽  
Turner B. Sutton
Keyword(s):  
Disease Severity ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Shoot Length ◽  
Lesion Length ◽  
Pyrus Calleryana ◽  
Intermediate Resistance ◽  
Artificial Inoculations

Fire blight, caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., is one of the most destructive diseases of plants in the Rosaceae subfamily Maloideae. Artificial inoculations, using E. amylovora strain E2002a, were conducted to determine levels of resistance to fire blight among taxa of flowering pears (Pyrus L. spp.) and quince (Chaenomeles Lindl. spp.). The level of resistance was measured as the length of the fire blight lesion as a percentage of overall shoot length. Considerable variation in resistance was observed among both pears and quince. Pyrus ussuriensis Maxim. `Prairie Gem' was highly resistant with a lesion length of 1% of the total shoot length. Pyrus calleryana Decne. `Bradford' was intermediate with a 50% lesion length while P. calleryana `Chanticleer' was significantly more resistant with a lesion length of 31%. Nine pear taxa were highly susceptible and did not differ significantly from 100% disease severity (total shoot death). Chaenomeles speciosa (Sweet) Nak. `Contorta' was highly resistant with a lesion length of 15%. Six quince taxa, including C. × superba (Frahm) Rehd. `Cameo', `Texas Scarlet', and `Jet Trail' were highly susceptible while nine other taxa showed intermediate resistance.

scholarly journals Analysis of Aggressiveness of Erwinia amylovora Using Disease-Dose and Time Relationships

2005 ◽  
Vol 95 (12) ◽  
pp. 1430-1437 ◽  
Author(s):  
Jordi Cabrefiga ◽  
Emilio Montesinos
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Gompertz Model ◽  
Immature Fruit ◽  
Infection Incidence ◽  
Progress Curve ◽  
Wide Range ◽  
Risk Forecasting ◽  
Extensive Collection ◽  
Modified Gompertz Model

The aggressiveness of an extensive collection of strains of Erwinia amylovora was analyzed using immature fruit and detached pear flower assays under controlled environmental conditions. The analysis was performed by means of a quantitative approach based on fitting data to mathematical models that relate infection incidence to pathogen dose and time. Probit and hyperbolic saturation models were used for disease-dose relationships and provided information on the median effective dose (ED50). Values of ED50 ranged from 103 to 106 CFU/ml (10 to 104 CFU per site of inoculation). A modified Gompertz model was used for disease-time relationships and provided information on the rate of infection incidence progression (rg) and time delayed to start of the incidence progress curve (t0). Values of rg ranged from near 0 to 1.90, and t0 varied from 1.3 to more than 10 days. The more aggressive strains showed high rg, low ED50 values, and short t0, whereas the less aggressive strains showed low rg, high ED50, and long t 0. The aggressiveness was dependent on plant material type and pear cultivars and was significantly different between strains of E. amylovora. Infectivity titration and kinetic analysis of progression of incidence of infections using the immature pear test and a standardized scale are proposed for assessment of strain aggressiveness. The implications of rg, ED50, and t0 for the epidemiology and management of fire blight are discussed, particularly the wide range of aggressiveness among strains, the degree of host specificity observed in pear isolates, the very high infective potential of this pathogen, the independent action of pathogen cells during infection, and the possible advantage of including aggressiveness parameters into fire blight risk forecasting systems.

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.

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.

scholarly journals Testing the virulence of some Hungarian Erwinia amylovora strains on in vitro cultured apple rootstocks

2000 ◽  
Vol 6 (4) ◽  
Author(s):  
M. Hevesi ◽  
J. Papp ◽  
E. Jámbor-Benczúr ◽  
K. Kaszáné Csizmár ◽  
I. Pozsgai ◽  
...  
Keyword(s):  
Host Plants ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Disease Development ◽  
Apple Rootstocks ◽  
Disease Rating ◽  
Different Strains

A useful method was improved to test and to evaluate the susceptibility of plants to fire blight and the virulence of E. amylovora strains. Six Hungarian strains from different host plants were tested on in vitro cultured apple rootstocks. Disease rating was used for the characterization of the process of disease development. The different strains had different capacity to cause disease, mainly in the first period of incubation. There were significant differences between the virulence of the strains.

scholarly journals Survival of Apple Rootstocks to Natural Infections of Fire Blight

2002 ◽  
Vol 12 (2) ◽  
pp. 239-241 ◽  
Author(s):  
D.C. Ferree ◽  
J.C. Schmid ◽  
B.L. Bishop
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Apple Rootstocks ◽  
Apple Trees ◽  
Wide Range ◽  
Dwarfing Rootstocks

Survival of replicated rootstock plantings of apple trees (Malus ×domestica) to fire blight (Erwinia amylovora) infection shows that a wide range of rootstock susceptibility exists. Trees on `Malling 26' (M.26), `Malling 9' (M.9), and `Mark' consistently had significant losses. Of the dwarfing rootstocks widely available commercially, `Budagovsky 9' (B.9) survived well with productive trees, but was not resistant to fire blight infection. The following experimental rootstocks had good survivability with many live productive trees in one or more trials: `Poland 2' (P.2), `Vineland 1' (V.1), `Malling 27 EMLA' (M.27 EMLA), `Budagovsky 491' (B.491), `Budagovsky 409' (B.409), `Vineland 7' (V.7), `Vineland 4' (V.4), and `Oregon Rootstock 1' (OAR1).

scholarly journals Resistance of Hosta Cultivars to Petiole Rot Caused by Sclerotium rolfsii var. delphinii

2003 ◽  
Vol 13 (2) ◽  
pp. 302-305 ◽  
Author(s):  
Brooke A. Edmunds ◽  
Mark L. Gleason ◽  
Stephen N. Wegulo
Keyword(s):  
Disease Severity ◽  
Plant Disease ◽  
Leaf Shape ◽  
Sclerotium Rolfsii ◽  
Disease Development ◽  
Wide Range ◽  
Bare Root

Eighteen cultivars of hosta (Hosta spp.), selected to represent a wide range of size, leaf shape and color, and genetics, were evaluated for reaction to Sclerotium rolfsii var. delphinii in a greenhouse in Ames, Iowa in 2000 and 2001. Bare-root, single-eye plants were planted in 15.2-cm (6-inch) pots in a soil-containing (2000) and soilless (2001) mix and grown in a greenhouse for 3 months. Plants were then inoculated by placing a carrot disk infested with mycelium of S. rolfsii at the base of the plant. Disease severity was assessed weekly for 6 weeks as percent symptomatic petioles. Disease development varied significantly (P < 0.05) among cultivars. Overall, `Lemon Lime', `Munchkin', `Nakaiana', `Platinum Tiara', and `Tardiflora' had the most severe symptoms and `Halcyon' showed the least disease.

scholarly journals Screening Cotoneaster for Resistance to Fire Blight by Artificial Inoculation

HortScience ◽  
2014 ◽  
Vol 49 (12) ◽  
pp. 1480-1485 ◽  
Author(s):  
Joseph J. Rothleutner ◽  
Ryan N. Contreras ◽  
Virginia O. Stockwell ◽  
James S. Owen
Keyword(s):  
Disease Resistance ◽  
Fire Blight ◽  
Bacterial Pathogen ◽  
Artificial Inoculation ◽  
Lesion Length ◽  
Sources Of Resistance ◽  
Landscape Plants ◽  
Whole Plant ◽  
Wide Range ◽  
Disease Pressure

Cotoneaster Medik. is a genus of ornamental landscape plants commonly affected by fire blight. Fire blight is a disease caused by the bacterial pathogen, Erwinia amylovora (Burrill) Winslow et al., that attacks a wide range of taxa in the apple subfamily (Maloideae; Rosaceae). To assess susceptibility of species and identify potential sources of resistance, we inoculated 52 taxa of Cotoneaster with E. amylovora. Disease severity was scored by percent shoot necrosis (lesion length/total shoot length). Disease screenings were conducted over 2 years and varying levels of susceptibility were observed. Some taxa were highly susceptible to fire blight and the disease resulted in whole plant mortality (C. rhytidophyllus Rehder & E.H. Wilson, C. rugosus E. Pritzel ex Diels, and C. wardii W.W. Smith). Other taxa repeatedly exhibited moderate to high levels of disease resistance [C. arbusculus G. Klotz, C. chungtinensis (T.T. Yu) J. Fryer & B. Hylmö, C. delsianus E. Pritzel var. delsianus, C. sikangensis Flinck & B. Hylmö, C. simonsii Baker, and C. splendens Flinck & Hylmö]. Ongoing studies are being conducted to determine if taxa with high levels of resistance under artificial inoculation will exhibit high levels of resistance in the field under natural disease pressure. Identifying sources of disease resistance will be useful for breeding programs to increase tolerance of these landscape plants with desirable horticultural characteristics to fire blight.

scholarly journals Screening Cotoneaster sp. for Resistance to Fire Blight Using Foliar Inoculation with Two Strains of Erwinia amylovora

HortScience ◽  
2021 ◽  
pp. 1-7
Author(s):  
Kristin E. Neill ◽  
Ryan N. Contreras ◽  
Virginia O. Stockwell ◽  
Hsuan Chen
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Branch Length ◽  
Lesion Length ◽  
Bacterial Disease ◽  
Total Branch Length ◽  
Landscape Functionality ◽  
Natural Mutation ◽  
Growth Habits ◽  
Type Iii Secretion Effector

The genus Cotoneaster is composed of ≈400 species with a wide variety of growth habits and forms. These hardy landscape shrubs used to be commonplace because of their low maintenance and landscape functionality. However, the interest in and sales of cotoneaster have decreased for a variety of reasons, with the greatest being its susceptibility to a bacterial disease fire blight caused by Erwinia amylovora. The resistances of 15 different genotypes of Cotoneaster to a wild-type strain of Erwinia amylovora (Ea153) and a strain LA635 that has a natural mutation in avrRpt2 that encodes for a type III secretion effector were tested separately by inoculating leaves. Fire blight resistance was assessed by calculating the percent shoot necrosis (PSN) [PSN = 100 × (lesion length ÷ total branch length)] at 6 to 8 weeks after inoculation. Across all experiments, Cotoneaster genotypes H2011-01-002 and C. ×suecicus ‘Emerald Sprite’ consistently had the lowest PSN values when inoculated with either strain. Cotoneaster ×suecicus ‘Emerald Beauty’ was significantly more resistant to Ea153 than to LA635, whereas C. splendens was significantly more susceptible to Ea153 than to LA635.

scholarly journals Identities and Geographic Distributions of Phytophthora spp. Causing Root Rot of Red Raspberry in Chile

Plant Disease ◽  
2002 ◽  
Vol 86 (12) ◽  
pp. 1357-1362 ◽  
Author(s):  
W. F. Wilcox ◽  
B. A. Latorre
Keyword(s):  
Geographical Location ◽  
Fruit Trees ◽  
Morphological Characters ◽  
Rubus Idaeus ◽  
The Other ◽  
Red Raspberry ◽  
Kiwi Fruit ◽  
Phytophthora Spp ◽  
Deciduous Fruit ◽  
Northern Sector

Five identified and two unidentified Phytophthora spp. were isolated from diseased roots of dead or declining red raspberry (Rubus idaeus L.) plants sampled from 18 plantations along a >1,000-km north-south axis in Chile. The array of Phytophthora spp. isolated was strongly associated with geographical location. P. fragariae var. rubi was recovered from 75 and 60% of the plantations in the southern (40°16′ to 40°53′ S latitude) and central (34°35′ to 37°23′ S latitude) production sectors, respectively, but was not recovered from any plantation in the northern sector (32°43′ to 33°45′ S latitude). Similarly, P. megasperma and P. gonopodyides were recovered from multiple plantations in the southern and central sectors but were not recovered in the northern sector. In contrast, P. cryptogea was recovered from 80% of the plantations in both the northern and central sectors but not from any plantation in the south, whereas P. citricolawas isolated from diseased plants in all sectors. In subsequent pathogenicity trials, P. citricola, P. cryptogea, and an unidentified Phytophthora sp. were equally and highly virulent on ‘Heritage’ red raspberry in each of three greenhouse experiments. The other species were less virulent in the experiment when soil temperatures were highest (mean weekly maximum = 27.5°C) relative to the other two experiments when temperatures were more moderate (mean weekly maxima of 19.9 and 23.7°C). Isolates identified as P. cryptogea were very similar to P. cryptogea isolates recovered previously from kiwi fruit in Chile and from deciduous fruit trees in California with respect to morphological characters and electrophoretic banding patterns of soluble mycelial proteins. Using the same criteria, isolates identified as P. gonopodyides were very similar to isolates recovered earlier from deciduous fruit crops in New York, which previously were identified as P. cryptogea sensu lato but are hereby reclassified as P. gonopodyides.

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