scholarly journals Aggressiveness of Phytophthora cactorum, P. citricola I, and P. plurivora from European Beech

Plant Disease ◽  
2010 ◽  
Vol 94 (8) ◽  
pp. 1009-1014 ◽  
Author(s):  
Jerry E. Weiland ◽  
Angela H. Nelson ◽  
George W. Hudler
Keyword(s):  
New York ◽  
Sugar Maple ◽  
Disease Incidence ◽  
European Beech ◽  
Infested Soil ◽  
Phytophthora Cactorum ◽  
Canker Disease ◽  
Common Lilac ◽  
Oyster Bay ◽  
Leaf Disks

Phytophthora cactorum, P. citricola I, and P. plurivora cause bleeding cankers on mature European beech (Fagus sylvatica) trees in the northeastern United States. Inoculation experiments were conducted to compare the aggressiveness of the three Phytophthora spp. on stems, leaf disks, and roots of European beech and common lilac (Syringa vulgaris) seedlings. Isolates were obtained from bleeding cankers on European beech from five cities in New York (Albany, Ithaca, Oyster Bay, Plainview, and Rochester) and from a bleeding canker on sugar maple in Ithaca, NY. Stems were inoculated with colonized agar plugs, leaf disks with a zoospore suspension, and roots via infested soil at three inoculum levels. All organs of inoculated beech and lilac developed disease except for lilac roots inoculated with zoospores of P. cactorum. Disease incidence, severity, and plant survival were dependent on isolate and were also influenced by the tissue inoculated and host. Isolates of P. cactorum were the least aggressive and caused less necrosis than isolates of P. citricola I and P. plurivora. Results emphasize the utility of stem and root inoculation for evaluation of this canker disease and underscore critical differences in species aggressiveness.

Early measures of basal area and canker disease predict growth potential of some hybrid poplar clones

1995 ◽  
Vol 25 (7) ◽  
pp. 1113-1118 ◽  
Author(s):  
Melinda H. Lo ◽  
Lawrence P. Abrahamson ◽  
Edwin H. White ◽  
Paul D. Manion
Keyword(s):  
New York ◽  
Disease Incidence ◽  
Hybrid Poplar ◽  
Basal Area ◽  
Growth Potential ◽  
Canker Disease ◽  
Percent Survival ◽  
Poplar Clones ◽  
Growth Differences ◽  
Stem Cankers

Differences in percent survival, canker disease rating, and basal area (m2•ha−1) were quantified for a plantation of 54 hybrid poplar clones in northern New York at ages 3 and 9 years to test the hypothesis that early growth and canker incidence indicate future growth. Differences in growth and canker severity between clones with similar parentage were assessed. Five of the seven clones, which exhibited high basal areas and low disease ratings at 3 years of age, maintained their growth potential at 9 years of age. Four of the five clones, which had 0% survival at 9 years of age, had low basal areas at 3 years of age. The growth potential of the remaining clones was not accurately predicted based on early measures of growth and disease incidence. Variation in basal area and canker rating among clones within the same parentage group made it impossible to use parentage as a predictor of growth potential. Correlations among canker rating and basal area and percent survival increased over time, suggesting that impacts of canker disease became more significant with age. Septoriamusiva Peck was suspected to be the primary cause of stem cankers, but isolations revealed the presence of many fungi.

scholarly journals Prevalence, Distribution and Identification of Phytophthora Species from Bleeding Canker on European Beech

2010 ◽  
Vol 28 (3) ◽  
pp. 150-158
Author(s):  
Angela H. Nelson ◽  
Jerry E. Weiland ◽  
George W. Hudler
Keyword(s):  
New York ◽  
Pathogen Detection ◽  
Management Strategies ◽  
European Beech ◽  
Disease Prevalence ◽  
Phytophthora Species ◽  
Phytophthora Cactorum ◽  
Building Management ◽  
Symptomatic Tissue ◽  
Soil Surveys

Abstract While bleeding canker of European beech trees (Fagus sylvatica) has long been recognized as a problem in Europe and North America, the cause in the northeastern United States has not been clear. To resolve this, we surveyed for disease prevalence on European beech, identified the pathogens involved, proved their pathogenicity, compared protocols for pathogen detection, and conducted a soil assay to determine pathogen presence in soil surrounding established trees in residential and commercial landscapes in New York, Pennsylvania, Maryland, Connecticut and Massachusetts. Approximately 40% of surveyed trees had bleeding cankers. While Phytophthora cactorum, P. gonapodyides, P. cambivora and two newly described species, P. citricola I and P. plurivora, were recovered from symptomatic tissue, P. citricola I and P. cactorum were most prevalent. All caused disease when artificially inoculated into European beech sapling stems, although P. cambivora and P. gonapodyides produced significantly smaller lesions. Recovery of the pathogen from symptomatic tissue using selective media, the preferred method of diagnosis, was significantly higher in the fall. ELISA detection was more successful and worked regardless of season, but did not allow identification to the species level. All five Phytophthora species were found in soil surveys; P. cambivora was most common, followed by P. cactorum and P. citricola I. These results provide a foundation for building management strategies to protect valuable specimens of European beech.

scholarly journals Disease Risk of Potting Media Infested with Phytophthora ramorum Under Nursery Conditions

Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 371-376 ◽  
Author(s):  
S. A. Tjosvold ◽  
D. L. Chambers ◽  
E. J. Fichtner ◽  
S. T. Koike ◽  
S. R. Mori
Keyword(s):  
Disease Risk ◽  
Disease Incidence ◽  
Sprinkler Irrigation ◽  
Soil Surface ◽  
Phytophthora Ramorum ◽  
Infected Leaf ◽  
Infested Soil ◽  
Pathogen Survival ◽  
Potting Media ◽  
Leaf Disks

Phytophthora ramorum has been found in potting media of containerized plants; however, the role of infested media on disease development under nursery conditions is unknown. This study assesses pathogen survival, sporulation, and infectivity to rhododendron plants in nursery pots with infected leaf litter that were maintained under greenhouse and field conditions. The influence of environmental conditions and irrigation method on disease incidence was also assessed. Infected leaf disks were buried below the soil surface of potted rhododendrons and retrieved at approximately 10-week intervals for up to 66 weeks. Pathogen survival was assessed by either isolation or induction of sporulation in water over three experimental periods. P. ramorum was recovered from infected leaf disks incubated in planted pots for longer than 1 year. Chlamydospores and sporangia formed on hydrated leaf disks but relative production of each spore type varied with the duration of incubation in soil. Root infections were detected after 40 weeks in infested soil. Foliar infections developed on lower leaves but only after spring rain events. Sprinkler irrigation promoted the development of foliar infections; no disease incidence was observed in drip-irrigated plants unless foliage was in direct contact with infested soil. Management implications are discussed.

scholarly journals Using Commercial Compost as Control Measures against Cucumber Root-Rot Disease

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Kamel Kamal Sabet ◽  
Magdy Mohamed Saber ◽  
Mohamed Adel-Aziz El-Naggar ◽  
Nehal Samy El-Mougy ◽  
Hatem Mohamed El-Deeb ◽  
...  
Keyword(s):  
Root Rot ◽  
Control Measure ◽  
Disease Incidence ◽  
Pathogenic Fungi ◽  
Pythium Ultimum ◽  
Control Measures ◽  
Infested Soil ◽  
Fungal Isolates ◽  
Cucumber Root

Five commercial composts were evaluated to suppress the root-rot pathogens (Fusarium solani (Mart.) App. and Wr, Pythium ultimum Trow, Rhizoctonia solani Kuhn, and Sclerotium rolfsii Sacc.) of cucumber plants under in vitro and greenhouse conditions. In vitro tests showed that all tested unautoclaved and unfiltrated composts water extracts (CWEs) had inhibitor effect against pathogenic fungi, compared to autoclaved and filtrated ones. Also, the inhibitor effects of 40 bacteria and 15 fungi isolated from composts were tested against the mycelial growth of cucumber root-rot pathogens. Twenty two bacteria and twelve fungal isolates had antagonistic effect against root-rot pathogens. The antagonistic fungal isolates were identified as 6 isolates belong to the genus Aspergillus spp., 5 isolates belong to the genus Penicillium spp. and one isolate belong to the genus Chaetomium spp. Under greenhouse conditions, the obtained results in pot experiment using artificial infested soil with cucumber root-rot pathogens showed that the compost amended soil reduced the percentage of disease incidence, pathogenic fungi population, and improved the cucumber vegetative parameters as shoot length, root length, fresh weight, and dry weight. These results suggested that composts are consequently considered as control measure against cucumber root-rot pathogens.

STUDIES ON THE SEEDLING DISEASE OF BARLEY CAUSED BY HELMINTHOSPORIUM SATIVUM P.K. & B.

1956 ◽  
Vol 34 (4) ◽  
pp. 653-673 ◽  
Author(s):  
R. A. Ludwig ◽  
R. V. Clark ◽  
J. B. Julien ◽  
D. B. Robinson
Keyword(s):  
Disease Incidence ◽  
Infested Soil ◽  
Disease Development ◽  
Toxic Activity ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Nutrient Salt ◽  
Helminthosporium Sativum ◽  
Treatment Comparisons

A standard sand – cornmeal – nutrient salt medium, for use in the production of artificial inoculum of Helminthosporium sativum, is described. This inoculum induces uniform plant disease development when thoroughly incorporated with the planting soil. The results presented clearly demonstrate the necessity of using a series of infestation levels in studies of factors affecting disease development in artificially infested soil. It is shown that considerable reliance can be placed on treatment comparisons within an experiment but that comparisons between experiments are much less accurate. The role of a toxin (or toxins) in disease development in barley seedlings has been demonstrated. The toxic activity was found to be distinct from that frequently encountered on addition of organic matter to soil. Results obtained suggest that toxin adsorption by the soil may play an important role in reducing disease incidence and severity.

A comparison of vegetative cover and tree community structure in three forested Adirondack watersheds

1985 ◽  
Vol 15 (5) ◽  
pp. 881-889 ◽  
Author(s):  
Christopher S. Cronan ◽  
Marc R. DesMeules
Keyword(s):  
New York ◽  
Sugar Maple ◽  
New York State ◽  
Basal Area ◽  
Red Maple ◽  
Vegetative Cover ◽  
Cover Type ◽  
Tree Community ◽  
Standing Dead ◽  
Annual Biomass

The Integrated Lake–Watershed Acidification Study (ILWAS) was conducted using three forested watersheds (Panther, Sagamore, and Woods) in the central Adirondack Park of New York State. By comparing the biogeochemical behavior of these watersheds, the ILWAS investigators hoped to elucidate the major ecosystem parameters controlling the fate of strong acids introduced from the atmosphere to lake–watershed systems. The ILWAS vegetation research program was designed to compare the quantitative patterns of forest structure in these midelevation watersheds. Results showed that the ILWAS catchments contain closely related variants of the northern hardwood – spruce – fir complex of the Adirondack region. The dominant tree species in these watersheds are beech (Fagusgrandifolia Ehrh.), red spruce (Picearubens Sarg.), sugar maple (Acersaccharum Marsh.), red maple (Acerrubrum L.), and yellow birch (Betulaalleghaniensis Britt.). On an areal basis, the watersheds contain 57–88% hardwood cover type and 5–29% spruce–fir cover type. Mean live basal area values range from 22 to 30 m2 ha−1 between catchments, while standing dead basal area values range from 4 to 8 m2 ha−1. Mean live stem densities range from 1400 to 1700 stems ha−1. Mean aboveground biomass projections for the tree stratum in the three watersheds range from 143 to 199 Mt ha−1, while estimated aboveground annual biomass increments range from 4.1 to 5.3% of standing biomass.

scholarly journals First Report of Stem Canker Disease of Pitaya (Hylocereus undatus and H. polyrhizus) Caused by Neoscytalidium dimidiatum in Taiwan

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 906-906 ◽  
Author(s):  
M. F. Chuang ◽  
H. F. Ni ◽  
H. R. Yang ◽  
S. L. Shu ◽  
S. Y. Lai ◽  
...  
Keyword(s):  
New York ◽  
Aerial Mycelium ◽  
Its Region ◽  
Stem Canker ◽  
Canker Disease ◽  
First Report ◽  
Neoscytalidium Dimidiatum ◽  
Succulent Plant ◽  
Sterile Medium ◽  
Hylocereus Undatus

Pitaya (Hylocereus undatus and H. polyrhizus Britt. & Rose), a perennial succulent plant grown in the tropics, is becoming an emerging and important fruit plant in Taiwan. In September of 2009 and 2010, a number of pitaya plants were found to have a distinctive canker on stems. The disease expanded quickly to most commercial planting areas in Taiwan (e.g., Pintung, Chiayi, and Chunghua). Symptoms on the stem were small, circular, sunken, orange spots that developed into cankers. Pycnidia were erumpent from the surface of the cankers and the stems subsequently rotted. After surface disinfestation with 0.1% sodium hypochloride, tissues adjacent to cankers were placed on acidified potato dextrose agar (PDA) and incubated at room temperature for 1 week, after which colonies with dark gray-to-black aerial mycelium grew. Hyphae were branched, septate, and brown and disarticulated into 0- to 1-septate arthrospores. Sporulation was induced by culturing on sterile horsetail tree (Casuarina equisetifolia) leaves. Conidia (12.79 ± 0.72 × 5.14 ± 0.30 μm) from pycnidia were one-celled, hyaline, and ovate. The internal transcribed spacer (ITS) region of ribosomal DNA was PCR amplified with primers ITS1 and ITS4 (2) and sequenced. The sequence (GenBank Accession No. HQ439174) showed 99% identity to Neoscytalidium dimidiatum (Penz.) Crous & Slippers (GenBank Accession No. GQ330903). On the basis of morphology and nucleotide-sequence identity, the isolates were identified as N. dimidiatum (1). Pathogenicity tests were conducted in two replicates by inoculating six surface-sterilized detached stems of pitaya with either mycelium or conidia. Mycelial plugs from 2-day-old cultures (incubated at 25°C under near UV) were inoculated to the detached stems after wounding with a sterile needle. Conidial suspensions (103 conidia/ml in 200 μl) were inoculated to nonwounded stems. Noninoculated controls were treated with sterile medium or water. Stems were then incubated in a plastic box at 100% relative humidity and darkness at 30°C for 2 days. The symptoms described above were observed on inoculated stems at 6 to 14 days postinoculation, whereas control stems did not develop any symptoms. N. dimidiatum was reisolated from symptomatic tissues. To our knowledge, this is the first report of N. dimidiatum causing stem canker of pitaya. References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, New York, 1990.

scholarly journals Screening of Citrus Cultivars Against Citrus Canker and Its Allelopathic Management

2019 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Cultural Practices ◽  
Integrated Management ◽  
Disease Incidence ◽  
Citrus Canker ◽  
Bacterial Disease ◽  
Canker Disease ◽  
Alternative Management ◽  
Integrated Management System ◽  
Ethanolic Extracts ◽  
Great Potency

Citrus canker is the most devastating bacterial disease. In Pakistan, where canker is endemic, cultural practices and chemical control is vital module of integrated management system. But due to non-prudent use of chemicals wicked impacts start to appear on human health and environment there was need of some alternative management which should be eco-friendly and has no adverse effect for human. Therefore, our present study was based on screening of different cultivars of citrus and allelopathic management of citrus canker. The results revealed that Cara cara navel and kinnow both performed as moderately susceptible response in field condition than all other cultivars of citrus in screening experiment. Consequently, disease incidence was observed increasing by increasing the lesion area and these cultivars can be suggested as a source of resistance against canker pathogen. In allelopathic management we observed that ethanolic extracts were more efficient than aqueous extracts and their efficacy was also increasing by increasing the concentration. Ethanolic extracts of jatropha (13.33cm) followed by amaltas (12.5cm), Arjun (11.13cm), Bougenvilla (7.21cm) have great potency against the pathogen. So these ethanolic extracts can be used as good and alternative management of citrus canker disease.

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