scholarly journals Growth, Flowering, and Powdery Mildew-related Responses of Witchhazels in Tennessee

2019 ◽  
Vol 29 (4) ◽  
pp. 507-515
Author(s):  
Lisa W. Alexander ◽  
Anthony L. Witcher ◽  
Fulya Baysal-Gurel
Keyword(s):  
Powdery Mildew ◽  
Disease Incidence ◽  
Incidence Data ◽  
Growing Seasons ◽  
Stem Necrosis ◽  
The Common ◽  
Native Pollinator ◽  
Height Increase ◽  
Nursery Field ◽  
Moderately Resistant

Witchhazel (Hamamelis sp.) cultivars are now available in an array of forms and flower colors, including several native, pollinator-friendly cultivars. However, little is known about response of witchhazel cultivars to powdery mildew (Podosphaera biuncinata) or the growth and flowering characteristics of witchhazel cultivars in a nursery field production setting. To provide growth, flowering, and disease incidence data to nursery growers, a cultivar trial including 23 cultivars of witchhazel representing five species was planted Apr. 2016 in McMinnville, TN. Plant growth, flowering density, length of bloom, and foliar disease incidence were evaluated over three growing seasons between May 2016 and Oct. 2018. ‘Zuccariniana’ japanese witchhazel (H. japonica) and ‘Sunglow’ common witchhazel (H. virginiana) showed the greatest height increase during the trial, and ‘Sunglow’ also added the most width during the trial. Cultivars with negative height or width growth included Sweet Sunshine chinese witchhazel (H. mollis) and hybrid witchhazels (H. ×intermedia) Aphrodite, Twilight, and Barmstedt Gold. Ten of the 23 cultivars experienced winter injury in the form of stem necrosis. Root crown sprouts were observed for all cultivars at least once during the trial. ‘Wisely Supreme’ chinese witchhazel had the longest bloom period, followed by ‘Westerstede’ and ‘Twilight’ hybrid witchhazels, whereas ‘Quasimodo’ vernal witchhazel (H. vernalis) had the greatest density of flowers. The hybrid witchhazel cultivars Aphrodite, Nina, and Arnold Promise and the common witchhazel cultivars Green Thumb and Sunglow were resistant to powdery mildew under trial conditions in all 3 years. ‘Twilight’ and ‘Barmstedt Gold’ hybrid witchhazel, ‘Little Suzie’ common witchhazel, ‘Wisley Supreme’ chinese witchhazel, and ‘Shibamichi Red’ japanese witchhazel were moderately resistant to powdery mildew.

scholarly journals The Epidemiology of Powdery Mildew on Concord Grapes

2001 ◽  
Vol 91 (10) ◽  
pp. 948-955 ◽  
Author(s):  
David M. Gadoury ◽  
Robert C. Seem ◽  
Andrea Ficke ◽  
Wayne F. Wilcox
Keyword(s):  
Powdery Mildew ◽  
Fruit Set ◽  
Disease Incidence ◽  
The United States ◽  
Seasonal Development ◽  
Peak Period ◽  
Late Season ◽  
Stage Of Development ◽  
Concord Grapes ◽  
Moderately Resistant

Vitis labruscana ‘Concord’ is a grape cultivar widely grown in the United States for processing into juice and other grape products. Concord grapes are sporadically but sometimes severely damaged by the grape powdery mildew pathogen, Uncinula necator. Although the foliage is often reported to be moderately resistant to powdery mildew, severe fruit infection occurs in some years. We observed the seasonal development of powdery mildew on leaves, rachises, and berries of unsprayed Concord grapevines. Inoculations of flower and fruit clusters revealed a brief period of berry susceptibility and a protracted period of rachis susceptibility. The rachis remained highly susceptible to infection, and the severity of rachis infection increased throughout the growing season until the rachis formed a periderm shortly before harvest. In contrast, berries were nearly immune to infection within 2 weeks after fruit set. Rachis and berry infections were detected before the disease was observed on foliage, and the incidence of rachis and berry infection often exceeded disease incidence observed on foliage until after fruit acquired substantial ontogenic resistance. Excellent control of fruit infection, and adequate control of leaf infection, was achieved by two fungicide applications targeted at the peak period of fruit susceptibility. Although Concord is thought to be moderately resistant to powdery mildew, the rachis is highly susceptible, and may be the avenue by which prebloom infections make their way onto the developing fruit. Late-season infection of the rachis neither spread to the fruit, nor did it cause fruit to drop prematurely, and may be of little economic consequence on fruit destined for processing. Although fruit of V. vinifera cultivars have been reported to remain susceptible to infection until berry sugar levels reach 8 to 15%, Concord fruit become nearly immune to infection nearly 6 weeks before this stage of development. Because powdery mildew does not become conspicuous on foliage until late summer, it is generally regarded as a late-season problem on Concord grapes, and previous management programs have reflected this belief. However, the greatest contribution to control of fruit infection is due to fungicides applied during the peak period of fruit susceptibility, from bloom until shortly after fruit set, long before the disease is observed on foliage.

scholarly journals Analysis of biochemical changes in cultivars of Black gram, Green gram and Pea against powdery mildew

2019 ◽  
Vol 2 (1) ◽  
pp. 5-10
Author(s):  
P P Waghmare ◽  
Sahera Nasreen
Keyword(s):  
Powdery Mildew ◽  
Disease Incidence ◽  
Field Studies ◽  
Biochemical Changes ◽  
Antimicrobial Compounds ◽  
Black Gram ◽  
Incidence Data ◽  
Major Constraint ◽  
Visual Screening ◽  
Defence Enzymes

Powdery mildew disease of the Black gram, Mung bean and Pea are a major constraint in the production. The resistance of plants to various pathogens depends on synthesis and level of various defence enzymes like hydrolases; peroxidases and antimicrobial compounds like phytoalexins (Kuc, l991 et al Kauffmann et al. l987; Boiler, l987; Mauch et al., l988; Kale and Choudhary 200l, Koche and Choudhary, 2005). The present study focused on visual screening of selected crop cultivars against the powdery mildew and its biochemical correlation with chlorophyll content, sugars, phenols content, PR-proteins and Phytoalexin activities. From the field studies, it was observed that selected crop was found with powdery mildew incidence. This disease incidence data was correlated with biochemical changes and level of chlorophyll, sugars, phenols, PR-protein and Phytoalexin activities. 

scholarly journals Spatial Pattern of Strawberry Powdery Mildew (Podosphaera aphanis) and Airborne Inoculum

Plant Disease ◽  
2014 ◽  
Vol 98 (1) ◽  
pp. 43-54 ◽  
Author(s):  
H. Van der Heyden ◽  
M. Lefebvre ◽  
L. Roberge ◽  
L. Brodeur ◽  
O. Carisse
Keyword(s):  
Powdery Mildew ◽  
Power Law ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Negative Binomial ◽  
Disease Incidence ◽  
Data Sets ◽  
Incidence Data ◽  
Airborne Inoculum ◽  
The Relationship

The relationship between strawberry powdery mildew and airborne conidium concentration (ACC) of Podosphaera aphanis was studied using data collected from 2006 to 2009 in 15 fields, and spatial pattern was described using 2 years of airborne inoculum and disease incidence data collected in fields planted with the June-bearing strawberry (Fragaria × ananassa) cultivar Jewel. Disease incidence, expressed as the proportion of diseased leaflets, and ACC were monitored in fields divided into 3 × 8 grids containing 24 100 m2 quadrats. Variance-to-mean ratio, index of dispersion, negative binomial distribution, Poisson distribution, and binomial and beta-binomial distributions were used to characterize the level of spatial heterogeneity. The relationship between percent leaf area diseased and daily ACC was linear, while the relationship between ACC and disease incidence followed an exponential growth curve. The V/M ratios were significantly greater than 1 for 100 and 96% of the sampling dates for ACC sampled at 0.35 m from the ground (ACC0.35m) and for ACC sampled at 1.0 m from the ground (ACC1.0m), respectively. For disease incidence, the index of dispersion D was significantly greater than 1 for 79% of the sampling dates. The negative binomial distribution fitted 86% of the data sets for both ACC1.0m and ACC0.35m. For disease incidence data, the beta-binomial distribution provided a good fit of 75% of the data sets. Taylor's power law indicated that, for ACC at both sampling heights, heterogeneity increased with increasing mean ACC, whereas the binary form of the power law suggested that heterogeneity was not dependent on the mean for disease incidence. When the spatial location of each sampling location was taken into account, Spatial Analysis by Distance Indices showed low aggregation indices for both ACCs and disease incidence, and weak association between ACC and disease incidence. Based on these analyses, it was found that the distribution of strawberry powdery mildew was weakly aggregated. Although a higher level of heterogeneity was observed for airborne inoculum, the heterogeneity was low with no distinct foci, suggesting that epidemics are induced by well-distributed inoculum. This low level of heterogeneity allows mean airborne inoculum concentration to be estimated using only one sampler per field with an overall accuracy of at least 0.841. The results obtained in this study could be used to develop a sampling scheme that will improve strawberry powdery mildew risk estimation.

scholarly journals The correct secret

Focaal ◽  
2016 ◽  
Vol 2016 (75) ◽  
pp. 45-58 ◽  
Author(s):  
Katherine A. Mason
Keyword(s):  
Public Health ◽  
Crucial Role ◽  
Common Good ◽  
Disease Incidence ◽  
Local Public Health ◽  
The Public ◽  
Incidence Data ◽  
Public Health Officials ◽  
Local Officials ◽  
The Common

In this article I argue that the global biosecurity project that arose out of the events of the SARS epidemic of 2003 created a new balance of secrecy and transparency within the public health arm of the Chinese state. In an effort to meet national and international demands for greater transparency in support of a “common good,” local public health officials engaged in what I call hypertransparency. This hypertransparency took two forms: the real-time online sharing of disease incidence data within the public health bureaucracy, and the over-performance of disease fighting strategies in front of a wider local and global public. Because local Chinese officials interpreted the “common good” differently from their international partners, neither of these efforts succeeded in erasing the crucial role that local officials continued to play in determining what should and should not be shared, and with whom. Secrecy continued to be an important component of China’s securitization efforts, with hypertransparency ultimately concealing more than it revealed.

scholarly journals Critical yield-point model to estimate damage caused by brown spot and powdery mildew in barley

2014 ◽  
Vol 44 (6) ◽  
pp. 957-963 ◽  
Author(s):  
Lenita Agostinetto ◽  
Ricardo Trezzi Casa ◽  
Amauri Bogo ◽  
Cristiano Sachs ◽  
Erlei Melo Reis ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Grain Yield ◽  
Disease Incidence ◽  
Block Design ◽  
Damage Threshold ◽  
Brown Spot ◽  
Economic Damage ◽  
Growth Stages ◽  
Southern Brazil ◽  
Growing Seasons

Barley (Hordeum vulgaris L.) is the second most important winter crop in Southern Brazil. The excessive rainfall in this region during the crop-growing season increases the frequency and intensity of foliar fungal diseases. The research aimed to determine the damage function equations (DFE) for the multiple pathosystem of barley brown spot and powdery mildew based on the relationship between grain yield and diseases intensity at different 'BRS Cauê' cultivar growth stages (GS) during 2009 and 2010 growing seasons in Southern Brazil. The experiments were arranged in a randomized complete block design with nine treatments and four replicates. The disease gradients were generated by strobilurins and triazols fungicides rates and number of applications on barley cv. Cauê. The fungicide applications and disease incidence and severity assessments were performed at the 22, 31, 39, 45 and 56 plant GS. The DFE were obtained by variance analysis and linear regression between grain yield and diseases intensity. Significant and negative DFE were obtained and the damage coefficients (DC) varied from 29.48 to 100.08 (2009) and from 36.08 to 113.57kg ha-1 (2010) for incidence, and from 219.5 to 6,276.6 (2009) and 102.3 to 5,292.5kg ha-1 (2010) for severity. The largest damage coefficients were obtained when diseases assessments were made on GS 22 and 31 on both growing seasons evaluated. DFE were used to calculate the economic damage threshold (EDT) as a criterion to indicate the fungicide application moment to control the diseases in cultivars similar to 'BRS Cauê' in Southern Brazil.

scholarly journals Characterization of favorable weather conditions with powdery mildew disease incidence on pumpkin

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Muhammad Ahmad Zeshan ◽  
Maryam Yousaf ◽  
Romana Anjum ◽  
Safdar Ali ◽  
Muhammad Usman Ghani
Keyword(s):  
Powdery Mildew ◽  
Disease Incidence ◽  
Weather Conditions ◽  
Weather Variables ◽  
Incidence Data ◽  
Powdery Mildew Disease ◽  
Management Approaches ◽  
Favorable Weather ◽  
The Relationship

Weather variables were characterized for the powdery mildew disease caused by Sphaerotheca fuliginea on pumpkin crop. The relationship between airborne conidia and incidence of powdery mildew on pumpkin was studied. Disease incidence data was recorded on weekly basis and correlated with prevailing environmental conditions.  All the environmental factors showed positive relationship with disease incidence except wind speed that exhibited negative correlation. Understanding of favorable environment is helpful to use appropriate management approaches.

Characterization of Strawberry Host Plant Resistance to Powdery Mildew caused by Podosphaera aphanis

2021 ◽  
Author(s):  
Michael Palmer ◽  
Gerald Holmes
Keyword(s):  
Powdery Mildew ◽  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Disease Incidence ◽  
Strawberry Cultivar ◽  
Plant Disease Management ◽  
Relative Differences ◽  
Moderately Resistant

Host plant resistance is an essential tool in plant disease management worldwide. Evaluations of strawberry cultivar resistance to powdery mildew were done previously in California, but many new cultivars have been released since the last evaluation in 1996 and merit evaluation for today’s growers. Two studies were conducted over the winter and summer of 2020, evaluating ten commonly grown cultivars. Powdery mildew-free plants were established in 3 L pots under high plastic tunnels and after three weeks (four- to five-leaf stage) moved into a powdery mildew-infested greenhouse. Disease incidence and severity ratings were taken weekly beginning at the first sign of disease. Ratings taken at 40 (winter) and 41 (summer) days after transfer to the greenhouse were used to make comparisons among cultivars. Significant differences were found in foliar disease severity among cultivars, but none were totally free of disease. Moderately resistant cultivars were ‘San Andreas’ and ‘Sweet Ann’. Highly susceptible cultivars were ‘BG 3.324’ and ‘Royal Royce’. Two field evaluations of the ten cultivars confirmed the observed relative differences in host resistance under field conditions. This information is valuable to California strawberry growers who select cultivars based in part on their susceptibility to economically important diseases such as powdery mildew.

scholarly journals Spatial Heterogeneity of the Incidence of Powdery Mildew on Hop Cones

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1433-1440 ◽  
Author(s):  
David H. Gent ◽  
Walter F. Mahaffee ◽  
William W. Turechek
Keyword(s):  
Powdery Mildew ◽  
Spatial Heterogeneity ◽  
Power Law ◽  
Binomial Distribution ◽  
Disease Incidence ◽  
Disease Assessment ◽  
Cluster Sampling ◽  
Data Sets ◽  
Ratio Test ◽  
Frequency Distributions

The spatial heterogeneity of the incidence of hop cones with powdery mildew (Podosphaera macularis) was characterized from transect surveys of 41 commercial hop yards in Oregon and Washington from 2000 to 2005. The proportion of sampled cones with powdery mildew ( p) was recorded for each of 221 transects, where N = 60 sampling units of n = 25 cones assessed in each transect according to a cluster sampling strategy. Disease incidence ranged from 0 to 0.92 among all yards and dates. The binomial and beta-binomial frequency distributions were fit to the N sampling units in a transect using maximum likelihood. The estimation procedure converged for 74% of the data sets where p > 0, and a loglikelihood ratio test indicated that the beta-binomial distribution provided a better fit to the data than the binomial distribution for 46% of the data sets, indicating an aggregated pattern of disease. Similarly, the C(α) test indicated that 54% could be described by the beta-binomial distribution. The heterogeneity parameter of the beta-binomial distribution, θ, a measure of variation among sampling units, ranged from 0.01 to 0.20, with a mean of 0.037 and a median of 0.015. Estimates of the index of dispersion ranged from 0.79 to 7.78, with a mean of 1.81 and a median of 1.37, and were significantly greater than 1 for 54% of the data sets. The binary power law provided an excellent fit to the data, with slope and intercept parameters significantly greater than 1, which indicated that heterogeneity varied systematically with the incidence of infected cones. A covariance analysis indicated that the geographic location (region) of the yards and the type of hop cultivar had little effect on heterogeneity; however, the year of sampling significantly influenced the intercept and slope parameters of the binary power law. Significant spatial autocorrelation was detected in only 11% of the data sets, with estimates of first-order autocorrelation, r1, ranging from -0.30 to 0.70, with a mean of 0.06 and a median of 0.04; however, correlation was detected in only 20 and 16% of the data sets by median and ordinary runs analysis, respectively. Together, these analyses suggest that the incidence of powdery mildew on cones was slightly aggregated among plants, but patterns of aggregation larger than the sampling unit were rare (20% or less of data sets). Knowledge of the heterogeneity of diseased cones was used to construct fixed sampling curves to precisely estimate the incidence of powdery mildew on cones at varying disease intensities. Use of the sampling curves developed in this research should help to improve sampling methods for disease assessment and management decisions.

Prevalence and Molecular Characterization Coat Protein Gene of Tobacco streak virus Causing Peanut Stem Necrosis Disease in Coastal and Rayalaseema Districts of Andhra Pradesh, South-India

2021 ◽  
Author(s):  
K. Saratbabu ◽  
K. Vemana ◽  
A.K. Patibanda ◽  
B. Sreekanth ◽  
V. Srinivasa Rao
Keyword(s):  
Coat Protein ◽  
Molecular Characterization ◽  
Andhra Pradesh ◽  
Disease Incidence ◽  
Tobacco Streak Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Streak Virus ◽  
Rt Pcr ◽  
Cp Gene ◽  
Stem Necrosis

Background: Peanut stem necrosis disease (PSND) caused by Tobacco streak virus (TSV) is a major constraint for groundnut production in Andhra Pradesh (A.P.). However, studies on prevalence and spread of the disease confined to only few districts of A.P. with this background current study focused on incidence and spread of the disease in entire state of A.P. Further an isolate of TSV occurring in A.P. characterized on the basis of genetic features by comparing with other TSV isolates originated from different hosts and locations from world.Methods: Roving survey was conducted during kharif 2017-18 in groundnut growing districts of Andhra Pradesh (A.P.) for peanut stem necrosis disease incidence. Groundnut plants showing PSND symptoms were collected and tested with direct antigen coating enzyme linked immunosorbent assay (DAC-ELISA). Groundnut samples found positive by ELISA once again tested by reverse transcription polymerase chain reaction (RT-PCR). The representative TSV-GN-INDVP groundnut isolate from Prakasham district was maintained on cowpea seedlings by standard sap inoculation method in glasshouse for further molecular characterization. The Phylogenetic tree for coat protein (CP) gene was constructed using aligned sequences with 1000 bootstrap replicates following neighbor-joining phylogeny.Result: Thirty-eight (52.7%) of seventy-two groundnut samples collected from different locations in A.P were given positive reaction to TSV by DAC-ELISA. For the first time, PSND incidence observed in coastal districts (Krishna, Guntur, Sri Pottisriramulu Nellore, Prakasham) of A.P. Maximum PSND incidence recorded from Bathalapalli (22.2%) and the minimum incidence in Mulakalacheruvu (4.1%). The coat protein (CP) gene of TSV-GN-INDVP groundnut isolate was amplified by RT-PCR and it shared maximum per cent nucleotide identity (97.51-98.62%) with TSV isolates from groundnut and other different crops reported in India. All Indian isolates cluster together irrespective of crop and location based on the phylogenetic analysis.

Some Issues of Morbidity with Temporary Incapacity for Work in the Ural Federal District

2021 ◽  
pp. 37-44
Author(s):  
AS Shastin ◽  
VG Gazimova ◽  
OL Malykh ◽  
TS Ustyugova ◽  
TM Tsepilova
Keyword(s):  
Public Health ◽  
Russian Federation ◽  
Disease Incidence ◽  
Federal District ◽  
Incidence Rates ◽  
Statistical Information ◽  
Working Age ◽  
The Russian Federation ◽  
The Common ◽  
Working Age Population

Introduction: In the context of a decreasing size of the working-age population, monitoring of the health status and disease incidence in this cohort shall be one of the most important tasks of public and occupational health professionals. Health risk management for the working population in the Russian Federation requires complete and reliable data on its morbidity, especially in view of the fact that its average age demonstrates a stable growth. It is, therefore, crucial to have precise and consistent information about the morbidity of the working-age population. Objective: The study aimed to assess incidence rates of diseases with temporary incapacity for work in the constituent entities of the Ural Federal District of the Russian Federation. Materials and methods: We reviewed data on disease incidence rates published by the Federal State Statistics Service in the Common Interdepartmental System of Statistical Information, Section 15.12, Causes of Temporary Disability, and Section 2.9.I.4, Federal Project for Public Health Promotion. The constituent entities under study were ranked according to the number of cases and days of temporary incapacity per 100 workers and E.L. Notkin scale was used to determine grade the incidence. The statistical analysis was performed using STATISTICA 10 software. Long-term average values of certain indicators, median values, standard deviation (σ) and coefficients of variation were estimated. The difference in the indices was assessed using the Mann-Whitney test. Results: Compared to 2010, incidence rates of diseases with temporary incapacity for work in the constituent entities of the Ural Federal District in 2019 demonstrated a significant decline. The sharp drop was observed in 2015. We also established that the Common Interdepartmental System of Statistical Information contains contradictory information on disease incidence. Conclusion: It is expedient to consider the issue of revising guidelines for organization of federal statistical monitoring of morbidity with temporary incapacity for work and to include this indicator in the system of public health monitoring.

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