Download or read book Effects of high temperature on grape powdery mildew Erysiphe necator written by Peggy Backup and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Epidemics of powdery mildew, arguably the most important disease of grapevines worldwide, are driven by moderate temperatures (21 to 30 C), but high temperatures can decrease growth and sporulation or eradicate the fungus. Using controlled environments, I investigated the response of 3 stages of Erysiphe necator's life cycle to 8 temperatures at 12 exposure times (1/4 to 24 h). Isolates of E. necator from 4 California production regions were used to evaluate the effects of heat treatments in 2 C increments from 30 to 44 C on conidial germination, colony size, and conidiospore production. After a 24-h exposure to 30, 32, or 34 C, conidia continued to germinate and colonies grew and sporulated. Lethal effects started at 36 or 38 C; lethal exposure times decreased with increasing temperature. At 44 C, less than 1 1/2 h was lethal. Sublethal exposure times that delayed colony growth were also detected. There were interactions among temperature, exposure time, and colony age, but not with source of isolate. The pathogen survived, grew, and reproduced at higher temperatures than previously reported; exposure time was as important as temperature in defining lethal and sublethal conditions. My results require verification with field studies to assess combined effects of repetitive exposure to high temperature and other environmental stresses.
Download or read book Consecutive Heat Acclimation and Modeling Uncertainty for Grapevine Powdery Mildew Erysiphe Necator written by Robin Alan Choudhury and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Grapevine powdery mildew, caused by the ascomycete Erysiphe necator, is a major threat to grapes worldwide. Despite its global impact on grape production, Erysiphe necator is sensitive to adverse environmental conditions, such as excess heat, free water and UV radiation. Using detached leaf co-culture assays, three-day-old single colonies of Erysiphe necator were exposed to one, two or three consecutive days of punctuated heat stress. While there was a consistent decrease in colony growth after a single heating event, there were little to no significant effects from subsequent heating events on colony growth. Similar effects were observed on the latent period, with a large initial effect from the first heat treatment and small marginal effects from subsequent heat treatments. Erysiphe necator colonies growing on live pot-grown plants were affected similarly by consecutive heat stress events. These data suggest that Erysiphe necator is more adaptable to environmental stress than previously thought. Several epidemiological models have been developed to predict powdery mildew disease onset and disease intensity based on weather conditions, most notably the Gubler-Thomas (GT) model. The GT model uses hourly temperature data to predict the disease intensity based on optimum and lethal conditions for the pathogen, and results in an advisory forecast for disease management. However, scattered weather stations and microclimates lead to uncertainty in hourly weather data in specific locations. There is also uncertainty about how the pathogen behaves in the field in response to unfavorable conditions, although recent and current studies are helping to fill these knowledge gaps. Fuzzy logic is a multi-valued logic developed to help deal with uncertainty. In this study, we used fuzzy logic to modify the GT model to adapt it to uncertainty in weather data and pathogen biology. The fungicide spray programs suggested by the GT and the fuzzy GT models were tested at eight sites in California and Oregon. Based on regular disease severity measurements, we found that the fuzzy GT model performed as well as the original GT model, and could reduce the overall number of fungicide applications while maintaining comparable disease control. The future prospects for such models are discussed.
Download or read book Relationship of Grape Powdery Mildew Erysiphe Necator to Vitis Sp Resistance Leaf Age and Vine Orientation and Temperature Induced Chasmothecia Dehiscence written by Hana A. Yokoyama-Hatch and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1. Resistance to powdery mildew, caused by Erysiphe necator, in grape (Vitis spp.) may control the pathogen as an alternative to fungicide sprays. The V. amurensis accessions DVIT 5825.9, 6633.78, 6493.3 from China; and V. ficifolia accession DVIT 2938.5 from South Korea were evaluated for resistance and compared to the susceptible V. vinifera `Carignane' and resistant `Karadzhandal'. DVIT 5825.9 was resistant to infection by powdery mildew isolate HZ-12 infection by limiting pathogen development and colony formation in detached leaves, and was also highly resistant in growth chamber tests. Mean leaf area ranged from 22.25 to 66.3 cm2 over 10 days, infection ranged from 13.2 to 100% over 5 days, primary appressorium ranged from 4.5 on day 1 to 0 on day 10, primary hypha ranged from 0.12 to 1.63 over 5 days, and except for DVIT 5825.9 colony diameter ranged in size from 8.33 to 350 micrometers over 10 days among the susceptible and resistant varieties and four accessions. Epidermal browning that was localized to one cell was observed after infection in accessions DVIT 5825.9, 6633.78, and 6493.3, but not in susceptible `Carignane'. An infected cell on DVIT 5825.9 was quickly followed by intense epidermal browning within 24 hours of infection and no colonies developed after 10 days of infection. E. necator infections were rated on entire plants in the growth chamber. `Carignane' was rated 1.67 with unlimited sporulating colonies, and rating for `Karadzhandal' and acccession DVIT 5825.9 were rated 9 with no mycelium observed on any leaves indicating high resistance to powdery mildew. DVIT 5825.9 is a promising new source of grape powdery mildew resistant germplasm. Chapter 2. Grape powdery mildew, caused by Erysiphe necator, is a worldwide disease of grapes (Vitis spp.), and chasmothecia, the overwintering stage, are the primary source of spring inoculum. The life stages and abundance of chasmothecia on leaves of different ages and vine orientations in the fall are related to sampling procedures to determine the necessity for control. Chasmothecia of all stages of maturity showed a trend of decreasing numbers from September to October. Mature chasmothecia were more abundant than immature, and intermediate chasmothecia were the least abundant. Fewer chasmothecia were found on young leaves than on old or middle aged leaves, and the number on middle and old aged leaves was similar. More chasmothecia were found on the north than the south side of the vines and the mean per 1 cm℗ø was 41 and 26, respectively. Mean field temperature was about 18°C and ranged from about 11-29°C and relative humidity ranged from 72-75% among the vines. Sampling for infection to determine the necessity for control should be based on the presence of mature chasmothecia on older leaves on the north side of the vines.Chapter 3. Chasmothecia dehiscence was used to evaluate ascospore release at three temperatures every 2 hr for 12 hr for application in the U. C. Davis Powdery Mildew Risk Assessment model (UCD PMRAM). Regression lines for total percentage dehisced chasmothecia did not differ among the temperatures of 15, 25, and 30°C during the evaluation period and slightly increased over time at 15°C. The total mean percentage dehisced chasmothecia for all durations was significantly different among the temperatures and the mean ± SEM was 6.80 ± 0.66 at 15°C, 10.0 ± 0.73 at 25°C, and 10.1 ± 0.55 at 30°C. Based on the results of this study, chasmothecia dehiscence and potential release of ascospores can be expected between 15 and 30°C.
Download or read book Compendium of Grape Diseases Disorders and Pests written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Some Environmental Factors which Influence the Development of the Grape Powdery Mildew Fungus Uncinula Necator Schw Burr written by Charles Joseph Delp and published by . This book was released on 1953 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Powdery Mildews written by Douglas Malcolm Spencer and published by . This book was released on 1978 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Control of Powdery Mildew of Grape Erysiphe Necator L Informed by Virtual Weather Modeling and Phyllosphere Community Insights written by Brianna McGuire and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Powdery mildew causes major damage to grapes in California, and is one of the most expensive diseases to treat worldwide. Typical treatment consists of frequent sulfur and synthetic fungicide applications from budbreak through veraison in winegrape cropping systems. The Gubler-Thomas (GT) model of grapevine powdery mildew epidemiology was developed in the early 90's and is currently used on approximately 300,000 acres in California. It is used to estimate powdery mildew risk based on temperature changes in order to identify intervals for fungicide applications and to decide what type of product to use for disease control. The model cannot predict risk without accurate weather information, but the costs of weather station purchase and establishment are often prohibitive to many growers. Instead of investing in a station, many growers use calendar-based fungicide applications or estimate risk based on output from regional weather stations. These treatment methods typically involve more frequent fungicide applications and can suggest inaccurate spray timing and application intervals. Virtual weather networks can interpolate data from existing, observing weather stations to give a prediction for the weather of a given area. Virtual weather data is freely available online, offering an alternative to in-field weather stations that determine powdery mildew risk and make recommendations. This study was conducted to examine the potential of virtual weather networks in calculating risk for participating commercial vineyards as a viable alternative to purchasing a weather station. In addition, disease control was assessed by comparing disease in vineyard blocks sprayed by Gubler-Thomas Risk Index recommendations generated by virtual vs. real weather stations. We found that site-specific weather data generated by either virtual or real weather stations reduced fungicide sprays by up to 20%. No difference in either disease incidence or severity was detected between grower standard treatments and station-driven treatments, indicating that use of the site-specific weather combined with the Gubler-Thomas model can result in fewer sprays for equivalent disease control. The potential uses and adoption strategies of this model and the virtual weather stations are discussed.
Download or read book Oidium or Powdery Mildew of the Vine written by Frederic T. Bioletti and published by Read Books Ltd. This book was released on 2016-08-26 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study on oidium originally printed in 1907 by the university of California. This book is thoroughly recommended for inclusion on the amateur or professional winegrower and historian of viticulture, containing a wealth of information and anecdote, much of which is still practical today. Extensively illustrated with drawings, diagrams and photographs. This book contains classic material dating back to the 1900s and before. The content has been carefully selected for its interest and relevance to a modern audience. It comes complete with a specially commissioned new biography of the author.
Download or read book The Mediterranean Diet written by Victor R Preedy and published by Academic Press. This book was released on 2014-11-19 with total page 699 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mediterranean Diet offers researchers and clinicians a single authoritative source which outlines many of the complex features of the Mediterranean diet: ranging from supportive evidence and epidemiological studies, to the antioxidant properties of individual components. This book embraces a holistic approach and effectively investigates the Mediterranean diet from the cell to the nutritional well-being of geographical populations. This book represents essential reading for researchers and practicing clinicians in nutrition, dietetics, endocrinology, and public health, as well as researchers, such as molecular or cellular biochemists, interested in lipids, metabolism, and obesity. Presents one comprehensive, translational source for all aspects of how the Mediterranean diet plays a role in disease prevention and health Experts in nutrition, diet, and endocrinology (from all areas of academic and medical research) take readers from the bench research (cellular and biochemical mechanisms of vitamins and nutrients) to new preventive and therapeutic approaches Features a unique section on novel nutraceuticals and edible plants used in the Mediterranean region
Download or read book Effects of Meteorological Factors on Conidia Infection and Production of Erysiphe Necator Podosphaera Clandestina and Podosphaera Macularis on the Leaves of Grape Cherry and Hop written by Hui Yan and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Grape, cherry and hop powdery mildew, caused by Erysiphe necator, Podosphaera clandestina, and P. macularis, are common problems in WA. Since conidia concentration is strongly related to disease intensity, it is an effective approach for forecasting powder mildews to explore the relationship between meteorological factors and conidia concentration. To assess effects of temperature (T) and relative humidity (RH) on the sporulation of P. clandestina, experiments were conducted using mature colonies of powdery mildew on the detached leaves. Study showed that sporulation were optimized at the T of 22°C and RH of 85%, and that 8 h incubation in dark with T of 10 °C and RH of 70--90% were favorable to sporulation. Similar studies were conducted to determine effects of RH on sporulation of P. macularis at 20°C. Results demonstrated that there was a significant negative linear relationship between conidia and RH at 80--97.5% during 48 h incubation. Under 24h fluctuating RH conditions, 8 h incubation at RH of 80% was favorable to sporulation. In the studies of ultraviolet (UV), conidia were trapped using Burkard volumetric sampler. Results showed that low levels of UV resulted in higher population of E. necator conidia, while high UV had the opposite effect. The thresholds of UV-B and UV-A were 0.5 W/m2 and 13 W/m2, respectively. The results of cross correlation analysis described negative relationship of UV with conidia concentration in current day and the previous two days. The cross correlations of conidia concentrations with UV-A were -0.306 in lag 0 and -0.182 in lag 2, and with UV-B were -0.311 in lag 0 and -0.235 in lag2. Modeling studies of conidia indicated that time series and multivariate techniques were appropriate methods on conidia forecasting. A dynamic prediction model of E. necator conidia was developed using AR (4) and PDLREG (7, 2). Predictors include previous 4 days conidia concentration, and previous 7 days average dewpoint and duration of temperature at polynomial degree of 2. Three dynamic prediction models of E. necator, P. clandestina, and P. macularis were developed using AR (4) and principle component analysis that simplified all related meteorological parameters to 5 components.
Download or read book A Monograph of the Erysiphales powdery Mildews written by Uwe Braun and published by . This book was released on 1987 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding Grapevine Powdery Mildew in New York State written by Michelle Moyer and published by . This book was released on 2011 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grapevine powdery mildew, caused by Erysiphe necator, is a cosmopolitan pathogen that threatens grape production worldwide. Accurate disease forecasts would enhance disease management, particularly where severity varies substantially between years, such as in New York State. Ascospore release occurred before local bud break of Vitis vinifera in NY, WA, NC and NJ, and was quantitatively related to accumulation of degree days and rain events during overwintering. Acute cold temperature events (
Download or read book Diseases of Fruit Crops written by R. S. Singh and published by . This book was released on 2000 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a description of symptoms of diseases, and of the identification and description of pathogens associated with the diseases from different parts of the world. The relationship of the diseases with the local environment and approaches to management, particularly non-chemical (where possible) is also covered. A comprehensive account of economically important diseases of major fruit trees and fruits of the subtropical regions, including the temperate climate areas of these regions, is provided.
Download or read book Adaptive Genomic Structural Variation in the Grape Powdery Mildew Pathogen Erysiphe Necator written by Laura Hill Jones and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Powdery mildew, caused by the obligate biotrophic fungus Erysiphe necator, is an economically important disease of grapevines worldwide. Large quantities of fungicides are used for its control, accelerating the incidence of fungicide-resistance. A shotgun approach was applied to sequence and assemble the genome of five E. necator isolates, and RNA-seq and comparative genomics were used to predict and annotate protein-coding genes. The results show that the E. necator genome is exceptionally large and repetitive and suggest that transposable elements are responsible for genome expansion. Frequent structural variations were found between isolates and included copy number variation in EnCYP51, the target of the commonly used sterol demethylase inhibitor (DMI) fungicides. A collection of 89 additional E. necator isolates from diverse vineyard sites was screened for copy number variation in the EnCYP51 gene and for presence/absence of a point mutation (Y136F) known to result in higher fungicide tolerance. The results show that an increase in EnCYP51 copy number is significantly more likely to be detected in isolates collected from fungicide-treated vineyards. Increased EnCYP51 copy numbers were detected with the Y136F allele, suggesting that an increase in copy number becomes advantageous only after the fungicide-tolerant allele is acquired. The results also show that EnCYP51 copy number influences expression in a gene-dose dependent manner and correlates with fungal growth in the presence of a DMI fungicide. Taken together these results demonstrate that copy number variation can be adaptive in the development of resistance to DMI fungicides in E. necator.
Download or read book Wildlife Disease Ecology written by Kenneth Wilson and published by Cambridge University Press. This book was released on 2019-11-14 with total page 693 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces readers to key case studies that illustrate how theory and data can be integrated to understand wildlife disease ecology.
Download or read book The Powdery Mildews written by Richard Robert Bélanger and published by American Phytopathological Society. This book was released on 2002 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Chapters within "The Fungi" bring up to date the nomenclature and classification of species, accurately reflecting the phylogeny of the fungi. An entire chapter is dedicated to the taxonomy of the powdery mildew fungi providing a new and reliable international source for all mycologists and plant pathologists. Convenient reference to both 'old' and 'new' names throughout the book will facilitate understanding and accelerate transition towards general use of the new taxonomy and nomenclature."--pub. desc.
Download or read book Grapevine Breeding Programs for the Wine Industry written by Andrew G. Reynolds and published by Elsevier. This book was released on 2015-04-20 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grapevine Breeding Programs for the Wine Industry: Traditional and Molecular Techniques summarizes recent trends in grapevine breeding, both in terms of research and practical programs. The first group of chapters covers the challenges faced by breeders and existing and emerging techniques used to combat them. Two further groups of chapters focus on grapevine breeding programs in different wine-producing countries around the world. With authoritative contributions from experts across the world’s winemaking regions, this book will be an essential reference for all those involved in viticulture and oeneology wanting to explore new methods, understand different approaches and refine existing practices. Covers challenges faced by breeders Highlights grapevine breeding programs in different wine-producing countries Contributions from experts across the world’s winemaking regions
