scholarly journals Timing of Perennial Canker Development in Apple Trees Caused by Neofabraea perennans and Neofabraea kienholzii

Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Christian G. Aguilar ◽  
Mark Mazzola ◽  
Chang-Lin Xiao
Keyword(s):  
Fruit Trees ◽  
Apple Fruit ◽  
Pome Fruit ◽  
Apple Trees ◽  
Canker Disease ◽  
Aphid Control ◽  
Neofabraea Perennans ◽  
Rot Disease ◽  
Canker Development ◽  
Bull's Eye

Members of the genera Neofabraea and Phlyctema have been reported to incite canker diseases of apple trees and a postharvest decay of apple fruit referred to as “bull’s-eye rot.” Neofabraea kienholzii was recently identified as participating in the bull’s-eye rot disease complex of apple and other pome fruit. In this study, apple twigs inoculated with N. kienholzii were shown to develop symptoms of a canker disease closely resembling perennial canker of pome fruit trees caused by N. perennans. Cankers resulting from infection by either Neofabraea spp. were more likely to be induced when twig inoculations occurred in October, and to a lesser degree in April, compared with all other inoculation dates evaluated in this study. Although N. kienholzii tended to induce cankers that were smaller in size compared with N. perennans, both pathogens shared similar seasonal trends in the initiation and expansion of tree cankers. N. perennans and N. kienholzii were recovered from inoculated twigs 6 months postinoculation regardless of when inoculations were conducted, indicating that both pathogens can survive on diseased twigs year-round. In addition, acervuli were observed more often on twigs inoculated in September and April compared with those inoculated in other months. Data from this work should help further our understanding of the epidemiology of N. kienholzii. This information also highlights the importance of proper branch pruning, canker removal, and aphid control. Such management activities should be conducted in a manner that helps minimize further spread of the pathogen.

scholarly journals The effect of Regalis® (prohexadione calcium) on the reduction of fire blight (Erwinia amylovora) severity in apple trees

2004 ◽  
Vol 10 (2) ◽  
Author(s):  
P. Sobiczewski ◽  
T. Bubán
Keyword(s):  
Active Ingredient ◽  
Fire Blight ◽  
Shoot Growth ◽  
Control Strategies ◽  
Fruit Trees ◽  
Pome Fruit ◽  
Apple Trees ◽  
Obvious Effect ◽  
One Year ◽  
Prohexadione Calcium

Due to the lack of effective and non-phytotoxic materials for control of the blossom and shoot blight phase of fire blight in pome fruit trees, two novel control strategies have emerged: shoot growth retardation by bioregulators and applying resistance inducer compounds. Prohexadione calcium (ProCa) is the active ingredient of the bioregulator Regalis® registered in several European countries. The reduction of shoot growth elongation is the most obvious effect of ProCa. Furthermore, it causes significant changes in the spectrum of flavonoids and their phenolic precursors, leading to the considerable reduction of susceptibility to fire blight. In Poland, potted one-year-old apple trees of cvs. Gala Must grafted on M.26 and Sampion on M.9 (in 2001) as well as Gala Must on P.60 (in 2002) were treated with Regalis® at a range of concentration of 250, 150 or 150 + 100 ppm, respectively. The inoculation of shoots was made with the strain No.691 of E. amylovora (107 cfu/ml), on the 7th and 21st'day after treatments with Regalis. In Hungary, during the years of 2002 and 2003 one-year-old container grown apple trees of the cvs. Idared/M.9 and Freedom/M.9 were treated with the prohexadione-Ca, the active ingredient of Regalis® 100, 150 or 200 ppm, two weeks before inoculation with the Ea 1 strain of E. amylovora (107 cfu/m1). In Poland, the suppression of fire blight in shoots reached up to 80%, depending on concentration and application time of Regalis®. In Hungary, the effect of prohexadione-Ca treatments, determined by the length of necrotic lesion developed, proved to be better than that of streptomycin used for comparison.

scholarly journals Outbreak of Leucostoma Canker Caused by Leucostoma cincta on McIntosh Apple Trees in Wisconsin

Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 923-923 ◽  
Author(s):  
D. E. Brown-Rytlewski ◽  
P. S. McManus
Keyword(s):  
Fruit Trees ◽  
Research Station ◽  
Randomly Amplified Polymorphic Dna ◽  
Cold Winter ◽  
Apple Trees ◽  
American Phytopathological Society ◽  
Adjacent Block ◽  
Canker Development ◽  
Mature Apple ◽  
Prunus Spp

In fall 1996, cankers were observed on branches of 7- to 9-year-old apple trees (Malus domestica cvs. Empire and McIntosh, strains Marshall and Redmax) in a research orchard in Sturgeon Bay, WI. By summer 1997, cankers had developed on scaffold limbs or the central leaders of 48 of 48 Marshall McIntosh trees and 26 of 40 Redmax McIntosh trees, but they rarely were found in an adjacent block of 40 Empire trees. In 1998, new cankers were not observed, but existing cankers expanded. By 1999, the Marshall McIntosh block was so severely affected it was removed; 50% of the Redmax trees and 13% of the Empire trees also were removed. Initially, cankers appeared as orange discolored areas on bark and frequently, but not always, were associated with pruning wounds. Canker expansion was greater during spring and fall than during summer. At later stages of canker development, bark cracked and peeled, and leaves distal to cankers died. These features were consistent with descriptions of Leucostoma canker of apple (2,3), a disease previously reported only in Michigan, Germany, and Iran (1–3). All of 10 cankers sampled in 1997 and several more cankers sampled in 1998 yielded fungal colonies on potato-dextrose agar resembling Leucocytospora spp., which are anamorphs of Leucostoma spp. (2). Colonies initially were white to buff and later turned brown. Conidium morphology was consistent with descriptions of Leucocytospora spp. (2). Alternaria spp. also were isolated frequently; other fungi, which were not identified, were isolated rarely. The presence of abundant pycnidia of Leuco-cytospora, but not perithecia of Leucostoma, on cankers was different from the signs described for Leucostoma canker caused by Leucostoma cincta in Michigan (2,3). However, simple matching coefficient analysis of randomly amplified polymorphic DNA data indicated 74% similarity between a typical isolate from apple in Wisconsin (97-82) and two isolates of L. cincta from apple in Michigan (3; ATCC 64878 and 64879) but only 49 to 54% similarity to L. cincta and L. persoonii isolated from stone fruit trees (Prunus spp.). Inoculation of wounded branches of mature apple trees (cvs. Golden Delicious and Cortland) with isolate 97-82 in July 1998 and 1999 resulted in cankers that resembled young cankers observed on trees in the research orchard. Eight weeks after inoculation, the pathogen was reisolated from these cankers, which fulfilled Koch's Postulates. Therefore, we conclude that Leucostoma canker was responsible for the serious damage to apple trees of different cultivars at the research station, with strains of McIntosh affected most severely. We speculate that low-temperature injury during the unusually cold winter of 1995-1996 might have created infection sites and predisposed trees to disease development. This is the first report of Leucostoma canker of apple in Wisconsin. It is rare that this disease causes such significant losses (2). References: (1) M. Ashkan. Iranian J. Plant Pathol. 30:33, 1994. (2) A. L. Jones and H. S. Aldwinckle, eds. 1991. Pages 40–41 in: Compendium of Apple and Pear Diseases. American Phytopathological Society, St. Paul, MN. (3) T. J. Proffer and A. L. Jones. Plant Dis. 73:508, 1989.

scholarly journals Sources and Availability of Inoculum and Seasonal Survival of Sphaeropsis pyriputrescens in Apple Orchards

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1043-1049 ◽  
Author(s):  
C. L. Xiao ◽  
Y. K. Kim ◽  
R. J. Boal
Keyword(s):  
Apple Fruit ◽  
Fruit Rot ◽  
Limiting Factor ◽  
North Central ◽  
Canker Disease ◽  
Growing Seasons ◽  
Apple Production ◽  
Rot Disease ◽  
Sampling Times ◽  
Sphaeropsis Rot

Sphaeropsis pyriputrescens is the cause of Sphaeropsis rot, a recently reported postharvest fruit rot disease of apple. Infection of apple fruit by the fungus is believed to occur in the orchard, and symptoms develop during storage or in the market. S. pyriputrescens also is the cause of a twig dieback and canker disease of apple and crabapple trees. To determine sources of pathogen inoculum in the orchard, twigs with dieback and canker symptoms, dead fruit spurs, dead bark, and fruit mummies on the trees were collected and examined for the presence of pycnidia of S. pyriputrescens. To monitor inoculum availability during the growing season from early May to early November, dead fruit spurs or twigs from Fuji trees, and twigs with dieback from crabapple trees (as a source of pollen for apple production) in a Fuji orchard as well as dead fruit spurs and dead bark from Red Delicious trees in a Red Delicious orchard were sampled periodically and examined for the presence and viability of pycnidia of S. pyriputrescens. To determine seasonal survival and production of pycnidia of the fungus on twigs, apple twigs were inoculated in early December, sampled periodically for up to 12 months after inoculation, examined for the presence of pycnidia, and subjected to isolation of the fungus from diseased tissues to determine its survival. Pycnidia of S. pyriputrescens were observed on diseased twigs, dead fruit spurs and bark, and mummified fruit on both apple and crabapple trees, suggesting that these tissues were the sources of inoculum for fruit infection in the orchard. With the combined observations from two orchards during three growing seasons, viable pycnidia of the fungus were present throughout the year and observed in 50 to 100% of the Fuji trees, >90% of crabapple trees, and 0 to 50% of the Red Delicious trees. S. pyriputrescens was recovered from diseased tissues of inoculated twigs at all sampling times up to 12 months after inoculation. The results suggest that S. pyriputrescens can survive as mycelium in diseased twigs in north-central Washington State and that availability of viable S. pyriputrescens pycnidia is unlikely a limiting factor for infection of apple fruit in the orchard leading to Sphaeropsis rot during storage.

scholarly journals Timing of Apple Fruit Infection by Neofabraea perennans and Neofabraea kienholzii in Relation to Bull’s-eye Rot Development in Stored Apple Fruit

Plant Disease ◽  
2017 ◽  
Vol 101 (5) ◽  
pp. 800-806 ◽  
Author(s):  
C. G. Aguilar ◽  
M. Mazzola ◽  
C. L. Xiao
Keyword(s):  
Pacific Northwest ◽  
Cold Storage ◽  
Disease Incidence ◽  
Growing Season ◽  
Apple Fruit ◽  
Postharvest Disease ◽  
Conidial Suspension ◽  
Pome Fruit ◽  
Fruit Growing ◽  
Bull's Eye

Bull’s-eye rot is a postharvest disease of pome fruit in the U.S. Pacific Northwest. The disease is caused by the fungi Neofabraea kienholzii, N. malicorticis, N. perennans, and N. vagabunda. Fruit infection by these pathogens is initiated in the orchard during the fruit-growing season but remains latent at harvest. For fruit held in postharvest cold storage, bull’s-eye rot symptom development is slow to progress, requiring at least 3 months before symptoms are first visible. In order to determine the timing of preharvest fruit infection in relation to bull’s-eye rot development in cold storage, ‘Red Delicious’ and ‘Fuji’ apple fruit were inoculated with a conidial suspension of N. perennans or N. kienholzii at different inoculation timings throughout the fruit growing seasons of 2012 to 2014. Fruit were harvested and stored at 0°C for up to 10 months, during which time disease incidence was recorded periodically. Results from this study demonstrate that apple fruit infection by either pathogen may occur at any point during the growing season. However, infections occurring over the 8-week period immediately prior to harvest yield a higher incidence of bull’s-eye rot in stored fruit compared with infections initiated earlier in the growing season.

scholarly journals Lichens of fruit trees in the selected locations in Podlaskie Voivodeship [North-Eastern Poland]

2017 ◽  
Vol 28 (4) ◽  
pp. 5-9 ◽  
Author(s):  
Anna Matwiejuk
Keyword(s):  
Fruit Trees ◽  
Lichen Species ◽  
Apple Trees ◽  
Partial Protection ◽  
Lichen Biota ◽  
North Eastern ◽  
Pear Trees ◽  
Fruit Orchards ◽  
Ramalina Farinacea

Abstract The aim of this paper is to present the diversity of the lichen species on fruit trees (Malus sp., Pyrus sp., Prunus sp. and Cerasus sp.) growing in orchards in selected villages and towns in the Podlaskie Voivodeship. Fifty-six species of lichens were found. These were dominated by common lichens found on the bark of trees growing in built-up areas with prevailing heliophilous and nitrophilous species of the genera Physcia and Phaeophyscia. A richer lichen biota is characteristic of apple trees (52 species) and pear trees (36). Lichens of the apple trees constitute 78% of the biota of this phorophyte growing in the fruit orchards in Poland. Of the recorded species, only two (Ramalina farinacea, Usnea hirta) are covered by partial protection in Poland.

scholarly journals Characterization of the Bull's Eye Rot of Apple in Chile

Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 485-490 ◽  
Author(s):  
Sylvana Soto-Alvear ◽  
Mauricio Lolas ◽  
Inés M. Rosales ◽  
Eduardo R. Chávez ◽  
Bernardo A. Latorre
Keyword(s):  
Morphological Characteristics ◽  
The United States ◽  
Apple Fruit ◽  
Maritime Transportation ◽  
Tubulin Genes ◽  
Internal Transcribed Spacer Sequences ◽  
Apple Production ◽  
Species Specific ◽  
Bull's Eye

Apple fruit in Chile are primarily produced for export to Asia, Europe, and the United States, which typically requires 15 to 40 days of maritime transportation. Therefore, Chilean apple production must fulfill the sanitization requirements imposed by the receiving countries. Under these circumstances, it was important to clarify the etiology of bull's eye rot that can severely affect ‘Cripps Pink’ apple and other late-harvest cultivars in Chile. Based on morphological characteristics and the partial sequence analysis of the internal transcribed spacer sequences and β-tubulin genes, Neofabraea alba was identified as the causal agent of the bull's eye rot of Chilean apple. These results were further corroborated using species-specific primers. The incidence of bull's eye rot varied considerably; for instance, in 2009, 0.0 to 58.7% in 38 Cripps Pink orchards surveyed in the relatively arid and humid apple-growing areas of Chile, respectively. There was no evidence for the presence of N. malicorticis or N. perennans, which are commonly identified as causal agents of bull's eye rot in other apple-producing countries. Altogether, these data suggest that N. alba might represent the predominant and possibly the only cause of bull's-eye rot of Chilean apple.

scholarly journals In Vitro Evaluation of Five Antimicrobial Peptides against the Plant Pathogen Erwinia amylovora

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 554
Author(s):  
Rafael J. Mendes ◽  
Laura Regalado ◽  
João P. Luz ◽  
Natália Tassi ◽  
Cátia Teixeira ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Antimicrobial Peptides ◽  
Erwinia Amylovora ◽  
Growth Curves ◽  
Fruit Trees ◽  
Membrane Permeabilization ◽  
Control Measures ◽  
Minimal Bactericidal Concentration ◽  
Pome Fruit

Fire blight is a major pome fruit trees disease that is caused by the quarantine phytopathogenic Erwinia amylovora, leading to major losses, namely, in pear and apple productions. Nevertheless, no effective sustainable control treatments and measures have yet been disclosed. In that regard, antimicrobial peptides (AMPs) have been proposed as an alternative biomolecule against pathogens but some of those AMPs have yet to be tested against E. amylovora. In this study, the potential of five AMPs (RW-BP100, CA-M, 3.1, D4E1, and Dhvar-5) together with BP100, were assessed to control E. amylovora. Antibiograms, minimal inhibitory, and bactericidal concentrations (minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), growth and IC50 were determined and membrane permeabilization capacity was evaluated by flow cytometry analysis and colony-forming units (CFUs) plate counting. For the tested AMPs, the higher inhibitory and bactericidal capacity was observed for RW-BP100 and CA-M (5 and 5–8 µM, respectively for both MIC and MBC), whilst for IC50 RW-BP100 presented higher efficiency (2.8 to 3.5 µM). Growth curves for the first concentrations bellow MIC showed that these AMPs delayed E. amylovora growth. Flow cytometry disclosed faster membrane permeabilization for CA-M. These results highlight the potential of RW-BP100 and CA-M AMPs as sustainable control measures against E. amylovora.

scholarly journals Qualities of Native Apple Cultivar Juices Characteristic of Central Europe

2012 ◽  
Vol 40 (1) ◽  
pp. 222 ◽  
Author(s):  
Otakar ROP ◽  
Martin POSOLDA ◽  
Jiri MLCEK ◽  
Vojtech REZNICEK ◽  
Jiri SOCHOR ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ascorbic Acid ◽  
Hydroxyl Radical ◽  
Antioxidant Capacity ◽  
Antioxidant Properties ◽  
Landscape Management ◽  
Ascorbic Acid Content ◽  
Fruit Trees ◽  
Apple Fruit ◽  
Scavenging Effect

During the last century due to the changes in landscape management, in country people’s lives and with intensive fruit-growing the native cultivars of apple fruit trees have been gradually disappearing. The aim of the study was to compare the juices made of native apple cider cultivars. The cultivars-‘Boikovo’, ‘Jadernicka moravska’, ‘Kardinal zihany’, ‘Panenske ceske’, ‘Parmena zlata zimni’, ‘Strymka’ growing in the locality of the Litencicke Hills in the eastern part of the Czech Republic were selected. For comparison, the fruits of commercial ‘Idared’ cultivar were also included. The chemical composition, antioxidant capacity, phenols, flavonoids and ascorbic acid content and the influence of juices on scavenging activity of nitric oxide and hydroxyl radical were measured. The mutual ratio of examined properties which were found, provide information about qualities and possibilities of use of native cultivars. High antioxidant properties characterize the juice of native apple cultivars. In particular, the ‘Strymka’ cultivar contained 2,637.34 mg of AAE (ascorbic acid equivalent) per litre in case of antioxidant capacity. In the juice of this cultivar the value of 144.05 mg of ascorbic acid per litre was recorded. As regards the ‘Panenske ceske’ cultivar, antioxidant capacity was 2,548.38 mg of AAE l-1 and in relation to ascorbic acid, the value was 145.35 mg l-1. Similarly, high values were observed in both cultivars concerning the scavenging effect of apple juices on hydroxyl radical and nitric oxide (the ‘Strymka’ cultivar 16.38% and 19.26%, the ‘Panenske ceske’ cultivar 16.31% and 18.60%).

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