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1
Bradshaw, Michael, and Patrick C. Tobin. "Sequencing Herbarium Specimens of a Common Detrimental Plant Disease (Powdery Mildew)." Phytopathology® 110, no. 7 (July 2020): 1248–54. http://dx.doi.org/10.1094/phyto-04-20-0139-per.
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Powdery mildew (Erysiphaceae) is a detrimental plant disease that occurs on a variety of economically important crops. Powdery mildew consists of over 873 species of fungal pathogens that affect over 10,000 plant species. Genetic identification of powdery mildew is accomplished using the internal transcribed spacer (ITS) and large subunit (LSU) regions of the nuclear ribosomal RNA gene cluster. The ITS and LSU regions of powdery mildews can be useful in ecological, epidemiological, phylogenetic, and taxonomic investigations. However, sequencing these regions is not without its challenges. For example, powdery mildew sequences are often contaminated with plant and/or fungal DNA. Also, there tends to be a limited amount and older specimens’ DNA can fragment over time. The success of sequencing powdery mildew often depends on the primers used for running polymerase chain reaction (PCR). The primers need to be broad enough that they match the majority of powdery mildew DNA yet specific enough that they do not align with other organisms. A review of the taxonomy and phylogeny of the powdery mildews is presented with an emphasis on sequencing the ITS + LSU genomic regions. Additionally, we introduce a new nested primer protocol for sequencing powdery mildew herbarium samples that includes six new powdery mildew-specific primers. The new sequencing protocol presented allows specimens up to 130 years old to be sequenced consistently. Sequencing herbarium specimens can be extremely useful for addressing many ecological, epidemiological, phylogenetic, and taxonomic problems in multiple plant pathogenic systems including the powdery mildews.
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Mwamahonje, Andekelile, Deusdedit Kilambo, Leon Mrosso, and Tileye Feyissa. "Screening for resistance of grape varieties to powdery mildew (Erysiphenecator) disease." JOURNAL OF ADVANCES IN AGRICULTURE 5, no. 1 (October 20, 2015): 585–90. http://dx.doi.org/10.24297/jaa.v5i1.4509.
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This study was conducted to evaluate the susceptibility of grapevine varieties to powdery mildew. Powdery mildew is a disease caused by a fungal, Erysiphenecator, and an obligate parasite of grapevine (Vitisvinifera L.). Powdery mildew causes drastic yield losses of 50 to 70%. Commercial grapevines grown in producing countries are susceptible to powdery mildew. Use of fungicides to control the disease is expensive and not environmentally friendly. Therefore, use of grapevine resistant varieties to powdery mildew is cost-effective control method. In this study, ten varieties (Black rose, Regina, Queen of Vineyards, Alphoncelavallee, Makutupora red, Chancellor, Halilibelyji, Syrah, Ruby seedless and Makutupora white) were screened for resistance to powdery mildew, using artificial inoculation of spore suspension and dry inoculums. Infected grape leaves were sampled from the field and grounded to obtain powder which was used as dry inoculum. The spore suspension inoculum was made by mixing powder with sterilized distilled water. The inoculation was done in two blocks with concentration of 2x105 spore/ml. Disease severity was evaluated based on a scale of 0 5; 0, means immune and 5, high level of disease severity. Results showed significant difference (P<0.05) of disease among grape vine varieties evaluated. It was found that 11.1% were resistant, 33.4% tolerant and 55% susceptible to disease. Grapevine variety Chancellor showed the highest level of resistance, and Black rose the most susceptible. The study demonstrates the effectiveness of using inoculation methods in screening resistance to powdery mildew.
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Věchet, L. "Development of powdery mildew and leaf rust epidemics in winter wheat cultivars." Plant, Soil and Environment 49, No. 10 (December 10, 2011): 439–42. http://dx.doi.org/10.17221/4154-pse.
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Development of powdery mildew and leaf rust epidemics was examined on three winter wheat cultivars with different predispositions to powdery mildew in three-year experiments. The progress of powdery mildew and leaf rust on the same cultivar was conditioned by its dissimilar susceptibility to the respective disease. Fit temperature played an important role at the beginning of the particular disease and during its progress. Significant differences in the disease severity of powdery mildew and leaf rust were recorded on single leaves. Disease severity of leaf rust was higher on upper leaves while disease severity of powdery mildew was higher on lower leaves.
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Wilson, Iain W., Céline L. Schiff, Douglas E. Hughes, and Shauna C. Somerville. "Quantitative Trait Loci Analysis of Powdery Mildew Disease Resistance in the Arabidopsis thaliana Accession Kashmir-1." Genetics 158, no. 3 (July 1, 2001): 1301–9. http://dx.doi.org/10.1093/genetics/158.3.1301.
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Abstract Powdery mildew diseases are economically important diseases, caused by obligate biotrophic fungi of the Erysiphales. To understand the complex inheritance of resistance to the powdery mildew disease in the model plant Arabidopsis thaliana, quantitative trait loci analysis was performed using a set of recombinant inbred lines derived from a cross between the resistant accession Kashmir-1 and the susceptible accession Columbia glabrous1. We identified and mapped three independent powdery mildew quantitative disease resistance loci, which act additively to confer disease resistance. The locus with the strongest effect on resistance was mapped to a 500-kbp interval on chromosome III.
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Beany, A. H., K. Pernezny, P. J. Stoffella, N. Havranek, and J. Sanchez. "MANAGEMENT OF DOWNY AND POWDERY MILDEW FOR WINTER SQUASH." HortScience 41, no. 3 (June 2006): 509E—509. http://dx.doi.org/10.21273/hortsci.41.3.509e.
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Control of downy (Pseudoperonospora cubensis) and powdery [(Podosphoera xanthii (Sphaerotheca fuliginea)] mildew on `Sweet Dumpling' winter squash (Cucurbita maxima) was evaluated at the University of Florida, IFAS, Indian River Research and Education Center (IRREC), in Fort Pierce, Florida during the Spring of 2005. Three foliar spray fungicide treatments were evaluated against an untreated control. Powdery and downy mildew ratings (estimated percentage of foliage damage) and marketable yields (mt/ha) were measured. Plants in the untreated plots had significantly higher powdery and downy mildew ratings. All fungicide treatments significantly reduced both mildews. There were no significant differences among treatments for marketable yield. Although the level of disease occurrence was not sufficient to reduce yields, Gavel alternated with Nova, Bravo Ultrex weekly, and Cabrio + Forum alternated with Bravo Ultrex + Manzate 75WG reduced downy mildew by ≥50%.
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Liyanage, K. K., S. Khan, P. E. Mortimer, K. D. Hyde, J. Xu, S. Brooks, and Z. Ming. "Powdery mildew disease of rubber tree." Forest Pathology 46, no. 2 (March 15, 2016): 90–103. http://dx.doi.org/10.1111/efp.12271.
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Koike, Steven T., and Dean A. Glawe. "First Report of Powdery Mildew of Fringed Willowherb (Epilobium ciliatum) Caused by Podosphaera epilobii in North America." Plant Health Progress 8, no. 1 (January 2007): 41. http://dx.doi.org/10.1094/php-2007-1112-01-br.
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Description and first report of powdery mildew caused by Podosphaera epilobii on E. ciliatum in North America are presented in this brief. The weed is commonly found in California's Salinas Valley (Monterey Co.). Confirmation of the powdery mildew disease indicates that this weed will not be a source of the powdery mildew diseases that affect nearby vegetable and ornamental crops. Accepted for publication 4 September 2007. Published 12 November 2007.
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Shattuck, V. I. "Powdery mildew-resistant UG3 and UG4 rutabaga germplasm." Canadian Journal of Plant Science 73, no. 1 (January 1, 1993): 301–2. http://dx.doi.org/10.4141/cjps93-046.
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UG3 and UG4 rutabaga (Brassica napus ssp. rapifera) germplasm lines are highly resistant to powdery mildew, and are suitable for developing powdery mildew-resistant B. napus cultivars. The lines were derived from a powdery mildew-resistant rutabaga mutant. Both lines are self-fertile, yield average weight roots that store well, but lack optimal root morphology. Key words: Rutabaga, germplasm, powdery mildew, disease resistance
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Hazelrigg, Ann L., Terence L. Bradshaw, and Gabriella S. Maia. "Disease Susceptibility of Interspecific Cold-Hardy Grape Cultivars in Northeastern U.S.A." Horticulturae 7, no. 8 (July 30, 2021): 216. http://dx.doi.org/10.3390/horticulturae7080216.
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Susceptibility to diseases of economically important grapes is critical to the evaluation of germplasm recommended for commercial production and for the development of sustainable production systems. In 2018–2019, the cold-hardy grape cultivars including ‘Brianna’, ‘Crimson Pearl’, ‘Itasca’, ‘Louise Swenson’, ‘Marechal Foch’, ‘Marquette’ ‘Petite Pearl’, ‘St. Pepin’, and ‘Verona’ were evaluated on non-treated vines for susceptibility to downy mildew, powdery mildew, black rot, anthracnose, Phomopsis leaf spot and fruit rot, and Botrytis bunch rot. No cultivars were consistently disease-free, and all exhibited some degree of black rot and powdery mildew infection. Relative susceptibility to disease was not consistent across both years, but ‘Brianna’ had greater incidence of black rot and ‘Louise Swenson’ showed lower incidence of powdery mildew in both years. The relatively new cultivars ‘Crimson Pearl’ and ‘Verona’ exhibited comparatively moderate disease susceptibility overall. Growers typically manage diseases with fungicides on commercial farms, so cultivar susceptibility is just one component of a sustainable pest management and production system.
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Windham, Mark T., and Willard T. Witte. "Naturally Occurring Resistance to Powdery Mildew in Seedlings of Cornus florida." Journal of Environmental Horticulture 16, no. 3 (September 1, 1998): 173–77. http://dx.doi.org/10.24266/0738-2898-16.3.173.
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Abstract Two production nursery fields of flowering dogwood, Cornus florida L., seedlings with a high incidence of powdery mildew were surveyed for plants free of symptoms and signs of the disease. In greenhouse trials most of the seedlings selected in the field survey for being free of powdery mildew were found to be escapes (had no disease resistance) or to exhibit partial resistance (unacceptable low levels of resistance). In those trials, twenty seedlings, representing approximately 0.1% of the seedlings examined in the field surveys, displayed resistance to powdery mildew similar to that of C. florida ‘Cherokee Brave’. This group of disease resistant seedlings will be used to develop new cultivars of white flowering dogwood resistant to powdery mildew and to investigate the inheritance of powdery mildew resistance mechanisms in flowering dogwood.
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Wolfenbarger, S. N., E. B. Eck, C. M. Ocamb, C. Probst, M. E. Nelson, G. G. Grove, and D. H. Gent. "Powdery Mildew Outbreaks caused by Podosphaera macularis on Hop Cultivars Possessing the Resistance Gene R6 in the Pacific Northwestern United States." Plant Disease 98, no. 6 (June 2014): 852. http://dx.doi.org/10.1094/pdis-11-13-1127-pdn.
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Resistant cultivars of hop (Humulus lupulus) have been grown, with the aim of helping to manage powdery mildew in the Pacific Northwest since the first report of the disease in the field in 1997 (4). A major objective of many breeding programs is development of resistance to powdery mildew, and this has generally been achieved by single resistance genes (qualitative resistance). One such gene, R6 (3), has been utilized extensively in new cultivars and has prevented epidemics of the disease in those cultivars across the Pacific Northwestern United States for approximately 15 years. In 2011, a grower in Washington State reported outbreaks of powdery mildew on cv. Apollo, which is thought to possess powdery mildew resistance derived from R6. Fungicides and cultural control measures were applied, and the grower reported no substantial crop damage from the disease. During the winter of 2012, the same grower planted rhizomes of cv. Apollo in a greenhouse in the Yakima Valley of Washington State and later found the plants to be affected by powdery mildew. Affected leaves from plants of cvs. Apollo, Newport, and Nugget (all reported [3] or assumed to possess R6 based on pedigree) grown in the same greenhouse were later provided to the authors. Conidia obtained from each affected plants were transferred to plants of the highly susceptible cv. Symphony, which is not known to contain any resistance genes. After 10 to 14 days of incubation, resultant conidia from each cultivar above (total of three isolates) were transferred to greenhouse grown plants of cvs. Nugget and Symphony and incubated at 18°C. Within 7 days, all three isolates produced powdery mildew colonies characteristic of P. macularis (2) on both cultivars. Cleistothecia did not develop in any colonies. In addition, Nugget and Symphony plants were inoculated with a field population of P. macularis originating from cultivars lacking R6 in Oregon. These inoculations on Nugget did not develop powdery mildew whereas Symphony plants did. Non-inoculated controls remained free of powdery mildew. Results were identical in two additional experiments. The sequence of the mating type idiomorph, MAT1-1, was obtained to confirm identity of the pathogen as P. macularis as described previously (1). The sequences were identical among the three isolates obtained from the greenhouse in Washington and isolates of P. macularis obtained previously from Oregon and Washington. MAT1-2 idiomorph was not detected in the isolates collected. While R6-virulent strains have been detected previously in race characterization experiments, these strains have not caused widespread epidemics of powdery mildew. The increasing prevalence of virulent strains of P. macularis and outbreaks of powdery mildew on formerly resistant cultivars necessitates changes in breeding strategies and disease management efforts to minimize damage resulting from the disease. The distribution of virulent strains of the pathogen and susceptibility of formerly resistance cultivars to powdery mildew are currently under investigation. References: (1) B. Asalfet et al. Phytopathology 103:717, 2013. (2) R. Bélanger et al. The Powdery Mildews: a Comprehensive Treatise. APS Press, St. Paul, MN, 2002. (3) P. Darby. Brew Hist. 121:94, 2005. (4) C. Ocamb et al. Plant Dis. 83:1072, 1999.
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Okoń, Sylwia, Tomasz Ociepa, Aleksandra Nucia, Magdalena Cieplak, and Krzysztof Kowalczyk. "Is Every Wild Species a Rich Source of Disease Resistance? Avena fatua L.—Potential Donor of Resistance to Powdery Mildew." Plants 10, no. 3 (March 16, 2021): 560. http://dx.doi.org/10.3390/plants10030560.
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Identifying effective sources of disease resistance is an important aspect of an effective plant protection strategy. Wild species related to cultivars constitute a rich reservoir of resistance genes. Studies conducted in oat have shown that wild species are donors of resistance genes to crown and stem rust, powdery mildew or fusarium head blight. The aim of the present study was to prove whether A. fatua could be a source of effective resistance genes to powdery mildew. This species is widespread all over the world due to its very good adaptability and can be regarded as a potential source of resistance to fungal diseases, including powdery mildew. The conducted research has shown that A. fatua is a species with a low level of resistance to powdery mildew when compared to other wild species of the genus Avena L. A total of 251 accessions were evaluated, and only 23 were identified as resistant to the individual isolates used in the host-pathogen tests. It follows that resistance to powdery mildew is not common among wild Avena species, and its good environmental adaptation is not associated to resistance to powdery mildew.
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Ishak, Muhammad Alif, and Budi Setiadi Daryono. "Identification and Analysis of Powdery Mildew Resistance in Melon (Cucumis melo L.) Cultivar Meloni." BIOEDUSCIENCE: Jurnal Pendidikan Biologi dan Sains 4, no. 1 (June 30, 2020): 1–10. http://dx.doi.org/10.29405/j.bes/411-104725.
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Background: A powdery mildew-resistant cultivar of melon is needed to increase melon yield crops. Meloni is a superior melon cultivar bred through a crossing between ♀ SL-3 and ♂ PI 371795, resulted by the Laboratory of Genetics and Breeding, Faculty of Biology, UGM. This study aimed to determine the level resistance of Meloni to powdery mildew infection and to identify the powdery mildew species that infected Meloni based on morphological characters. Methods: Meloni seeds were germinated and planted in the greenhouse of PIAT UGM. Powdery mildew spores were inoculated into the leaves after ±2 weeks of age. Leaf infected were scored using the gridline every 3 days for 6 weeks. Scoring results were converted to the diseases index score. Furthermore, powdery mildew species was identified using morphological characters. Results: Meloni had a tolerance level of resistance to the powdery mildew infection. Based on the morphological characters with fibrosin bodies, conidia ovoid-shape and the position of the germ tube in the lateral part of the conidia, powdery mildew that infected Meloni was expected as P. xanthii. Conclusions: Meloni can be expected as an alternative to superior melon seeds resistant to pest and disease infections especially powdery mildew.
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ZHANG, L., B. Y. YANG, S. LI, and A. H. GUO. "Disease–weather relationships for wheat powdery mildew under climate change in China." Journal of Agricultural Science 155, no. 8 (July 27, 2017): 1239–52. http://dx.doi.org/10.1017/s0021859617000442.
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SUMMARYLittle is known about the quantitative relationships between wheat powdery mildew (Blumeria graminis f.sp. tritici) epidemics and climatic variables at the provincial scale in China, particularly under climate change. The present study assesses the actual disease process and corresponding impact on wheat yield and addresses climatic-driven variables that affect a powdery mildew epidemic. Powdery mildew increased in frequency from 1981 to 2010, and wheat yield decreased in most regions. It was clear that differences in disease and yield loss occurred temporally and spatially. Although particular weather variables were positively or negatively related to the disease, multiple stepwise regression analysis indicated that mostly fewer than three variables affected prevalence and severity of powdery mildew in each province. In most cases, some combination of higher temperature, humidity, rainfall and wind led to higher disease severity. These weather factors had different effects on disease development. The influence of climatic variables on powdery mildew tended to decrease from 1981 to 2010, whereas the effect of non-climatic factors increased and was attributed mainly to the use of fungicides and resistant cultivars. Therefore, the results of the current study suggest that wheat powdery mildew in China will not increase consistently in the future. In addition, the quantitative assessment method used in the current study can generally provide a good way to identify disease epidemics under climate change.
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E Stummer, Belinda, I. Leigh Francis, Andrew J Markides, and Eileen S Scott. "Powdery mildew and wine quality." Microbiology Australia 24, no. 3 (2003): 20. http://dx.doi.org/10.1071/ma03320.
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Powdery mildew, caused by the fungus Uncinula necator, is a widespread and economically important disease of grapevines. The fungus grows superficially on green tissues of grapevines and other members of the Vitaceae. Powdery mildew costs the Australian grape and wine industry approximately A$30 million per year in terms of lost yield, reduced quality and disease management.
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Jumanazarov, Gayrat, Mirakbar Zuparov, Mukhiddin Mamiev, and Abdurakhmon Allayarov. "Distribution and damage of powdery mildew disease in cassis and raspberry in Tashkent province, Uzbekistan." E3S Web of Conferences 284 (2021): 03017. http://dx.doi.org/10.1051/e3sconf/202128403017.
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This article provides information on the species composition of the powdery mildew pathogen found in medicinal plants cassis and raspberry, as well as its distribution, development and damage to farms in the Tashkent province. The development of raspberry powdery mildew in the farms studied and the relatively low yield loss may depend on the raspberry navigation planted on the farm, the agronomic practices carried out, and the disease control measures taken. The prevalence of powdery mildew in cassis was 25.6-49.8%, development was 14.2-27.1%, yield loss was 12.0-20.0%, and the prevalence of powdery mildew in raspberry was 12.5-31.4%, development was 5.3-25.2%, and yield loss was 10.9-22.7%.
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Du, Shi Zhou, Wen Jiang Huang, Rong Fu Wang, Ju Hua Luo, Jin Ling Zhao, and Lin Yuan. "Application of Continuum Removal Method for Estimating Disease Severity Level of Wheat Powdery Mildew." Advanced Materials Research 396-398 (November 2011): 2012–17. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.2012.
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The hyperspectral bands sensitive to the disease severity levels of wheat powdery mildew was elucidated in this study. The disease severity levels of wheat powdery mildew were also inverted by the extracting characteristic parameters, which provided a basis for detecting the wheat powdery mildew using hyperspectral data. The spectral data of single leaves was obtained at heading stage, the spectral characteristic parameters and sensitivity of wheat leaves were analyzed qualitatively and quantitatively. The result showed that spectral reflectivity within the visible wavebands (400—760 nm) was increased with the aggravating disease severity levels. The spectral sensitivity reached the maximum value within visible wavebands and the optimal sensitive bands for detecting disease severity levels was 630—680nm. After the spectrum was continuum removal-treated, the absorption position moved to longer wavelength with the aggravating disease severity levels and the disease severity levels showed extremely significant negative correlations with the absorption height, absorption width and absorption area. The linear regression equation has high determination coefficient and low root mean square error using the right AAI as independent variable to establish the model. Moreover, the precision verification test also showed that the model performed best in monitoring wheat powdery mildew. In conclusion, disease severity levels of wheat powdery mildew could be inverted effectively by hyperspectral technology, which provides the foundation for detecting wheat powdery mildew.
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Asalf, Belachew, Rodrigo B. Onofre, David M. Gadoury, Natalia A. Peres, and Arne Stensvand. "Pulsed Water Mists for Suppression of Strawberry Powdery Mildew." Plant Disease 105, no. 1 (January 2021): 71–77. http://dx.doi.org/10.1094/pdis-04-20-0735-re.
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Powdery mildew (Podosphaera aphanis) is a destructive and widespread disease of strawberry (Fragaria × ananassa), especially when susceptible cultivars are grown in high plastic tunnels or glasshouses. Many powdery mildews thrive in humid environments but free water films on plant surfaces can inhibit conidial germination of some species. We hypothesized that P. aphanis might be directly suppressed by rain through the action of water films and meteoric water. In repeated experiments, the hydrophobic conidia of P. aphanis collected on the surface of water droplets, resulting in their removal when the droplets rolled over the leaf surfaces and fell to the ground. Meteoric water and water films also damaged conidiophores. Brief midday water mists applied in pulses lasting 1 min each four times per day were as effective as multiple fungicide treatments in suppressing powdery mildew. Rapid drying of the pulsed mists resulted in effective suppression of powdery mildew without consequent increases of fungal pathogens that might benefit from water films. The timing and duration of water sprinkling has been refined to the point where it can provide a commercially relevant degree of suppression of powdery mildew on strawberry in a high-tunnel production system.
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Bartoš, P., V. Šíp, J. Chrpová, J. Vacke, E. Stuchlíková, V. Blažková, J. Šárová, and A. Hanzalová. "Achievements and prospects of wheat breeding for disease resistance." Czech Journal of Genetics and Plant Breeding 38, No. 1 (July 30, 2012): 16–28. http://dx.doi.org/10.17221/6107-cjgpb.
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Achievements and prospects of wheat breeding for disease resistance in the world and in the Czech Republic are reviewed. Attention is paid to rusts, powdery mildew, leaf blotch, glume blotch, tan spot, fusarium head blight, common and dwarf bunt, eyespot, barley yellow dwarf virus on wheat and wheat dwarf virus. Genes for resistance to rusts and powdery mildew in the cultivars registered in the Czech Republic are listed. Promising resistance genes and sources of resistance to the above mentioned diseases are reviewed. Prospects of resistance breeding including application of methods of molecular genetics and development of synthetic hexaploids are outlined.
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Tratwal, Anna, and Jan Bocianowski. "Blumeria graminis f. sp. hordei virulence frequency and the powdery mildew incidence on spring barley in the Wielkopolska province." Journal of Plant Protection Research 54, no. 1 (January 1, 2014): 28–35. http://dx.doi.org/10.2478/jppr-2014-0005.
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Abstract Powdery mildew caused by fungi Blumeria graminis f. sp. hordei is one of the most common barley diseases in Polish meteorological conditions. The powdery mildew fungus is made up of different races and forms that are highly specialized. Barley cultivars might be resistant to a certain race of the mildew fungus, but susceptible to another race. Development of the disease is rapid in temperatures from 12 to 20°C, and in humid weather. The aim of the two-year experiment was to assess B. graminis f. sp. hordei virulence frequency and powdery mildew occurrence on five spring barley cultivars. Virulence frequency of the pathogen depended on place and term of exposition. The occurrence of powdery mildew on spring barley cultivars depended on virulence frequency of the pathogen and weather conditions.
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Witte, W. T., M. T. Windham, R. J. Sauve, and P. C. Flanagan. "Growth Index and Disease Ratings of 60 Lilac Cultivars in Tennessee." HortScience 31, no. 4 (August 1996): 660e—660. http://dx.doi.org/10.21273/hortsci.31.4.660e.
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Sixty accessions of commercially available lilac cultivars were planted May 1994 and immediately placed under drip irrigation and fertilized regularly. Powdery mildew appeared in July 1994 and was rated on a scale of 0 (healthy) to 5 (totally mildewed) in July, August, and September. Mean growth index (GI = cm height + cm mean width) was calculated for each cultivar in Fall 1994 and 1995. Fastest growth (GI = 75 to 45 respectively) occurred in the group including chinensis `Rothomagensis', meyeri `Dwarf Korean', reticulata `Ivory Silk', prestoniae `Isabella', `Mrs. Harvey Bickle', `Excel', `Katherine Havemeyer', `Mme. F. Morel', `Silver King', `Leon Gambetta', `Mount Baker', and microphylla `Superba'. Data will be presented on powdery mildew ratings for the 1995 season.
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Karkanis, A., D. Bilalis, A. Efthimiadou, and N. Katsenios. "Effects of field bindweed (Convolvulus arvensis L.) and powdery mildew [Leveillula taurica (Lev.) Arn.] on pepper growth and yield – Short communication." Horticultural Science 39, No. 3 (August 15, 2012): 135–38. http://dx.doi.org/10.17221/213/2011-hortsci.
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Field experiments were conducted to determine the effects of field bindweed and powdery mildew on growth and yield of a pepper crop. This study also evaluated the efficacy of fungicide application programs for controlling powdery mildew. Field bindweed influenced growth and yield of pepper. The greatest dry weight and yield of pepper were recorded with weed-free control treatment. Moreover, powdery mildew was severe. The fungicide application programs positively influenced growth and yield of pepper. The control plots had the lowest yield of pepper. The first symptoms of powdery mildew on pepper plants developed 20–25 days after powdery mildew diagnosis on field bindweed. Two azoxystrobin applications, at 10 and 25 days after infection of field bindweed by powdery mildew, restricted the disease progress. Our results indicate that field bindweed is highly susceptible to powdery mildew infection and could be used as an indicator species of L. taurica presence in pepper plants.
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Misra, A. K. "Powdery mildew - a serious disease of mango." Journal of Applied Horticulture 03, no. 01 (June 15, 2001): 63–68. http://dx.doi.org/10.37855/jah.2001.v03i01.16.
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Madhuri, V., and G. Karuna Sagar. "Management of Powdery Mildew Disease in Sesamum." International Journal of Current Microbiology and Applied Sciences 7, no. 09 (September 10, 2018): 3339–44. http://dx.doi.org/10.20546/ijcmas.2018.709.414.
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Khalifa, E. Z., and H. M. Awad. "STUDIES ON POWDERY MILDEW DISEASE OF GRAPES." Menoufia Journal of Plant Protection 3, no. 4 (October 1, 2018): 161–62. http://dx.doi.org/10.21608/mjapam.2018.123958.
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Olmstead, James W., Gregory A. Lang, and Gary G. Grove. "Inheritance of Powdery Mildew Resistance in Sweet Cherry." HortScience 36, no. 2 (April 2001): 337–40. http://dx.doi.org/10.21273/hortsci.36.2.337.
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Most sweet cherry (Prunus avium L.) cultivars grown commercially in the Pacific Northwestern states of the United States are susceptible to powdery mildew, caused by the fungus Podosphaera clandestina (Wall.:Fr.) Lev. The disease is prevalent in the irrigated arid region east of the Cascade Mountains in Washington State. Little is known about genetic resistance to powdery mildew in sweet cherry, although a selection (PMR-1) was identified at Washington State Univ.'s Irrigated Agriculture Research and Extension Center that exhibits apparent foliar immunity to the disease. The objective of this research was to determine the inheritance of powdery mildew resistance from PMR-1. Reciprocal crosses were made between PMR-1 and three high-quality, widely-grown susceptible cultivars (`Bing', `Rainier', and `Van'). Resultant progenies were screened for reaction to powdery mildew colonization using a laboratory leaf disk assay. Assay results were verified by natural spread of powdery mildew among the progeny in a greenhouse and later by placing them among infected trees in a cherry orchard. Segregation within the progenies for powdery mildew reaction fit a 1 resistant: 1 susceptible segregation ratio (P ≤ 0.05), indicating that resistance to powdery mildew derived from PMR-1 was conferred by a single gene.
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Graeff, Simone, Johanna Link, and Wilhelm Claupein. "Identification of powdery mildew (Erysiphe graminis sp. tritici) and take-all disease (Gaeumannomyces graminis sp. tritici) in wheat (Triticum aestivum L.) by means of leaf reflectance measurements." Open Life Sciences 1, no. 2 (June 1, 2006): 275–88. http://dx.doi.org/10.2478/s11535-006-0020-8.
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AbstractThe ability to identify diseases in an early infection stage and to accurately quantify the severity of infection is crucial in plant disease assessment and management. A greenhouse study was conducted to assess changes in leaf spectral reflectance of wheat plants during infection by powdery mildew and take-all disease to evaluate leaf reflectance measurements as a tool to identify and quantify disease severity and to discriminate between different diseases. Wheat plants were inoculated under controlled conditions in different intensities either with powdery mildew or take-all. Leaf reflectance was measured with a digital imager (Leica S1 Pro, Leica, Germany) under controlled light conditions in various wavelength ranges covering the visible and the near-infrared spectra (380–1300 nm). Leaf scans were evaluated by means of L*a*b*-color system. Visual estimates of disease severity were made for each of the epidemics daily from the onset of visible symptoms to maximum disease severity. Reflectance within the ranges of 490780 nm (r2 = 0.69), 510780nm (r2 = 0.74), 5161300nm (r2 = 0.62) and 5401300 nm (r2 = 0.60) exhibited the strongest relationship with infection levels of both powdery mildew and take-all disease. Among the evaluated spectra the range of 490780nm showed most sensitive response to damage caused by powdery mildew and take-all infestation. The results of this study indicated that disease detection and discrimination by means of reflectance measurements may be realized by the use of specific wavelength ranges. Further studies have to be carried out, to discriminate powdery mildew and take-all infection from other plant stress factors in order to develop suitable decision support systems for site-specific fungicide application.
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Gent, David H., Claudia Probst, Mark E. Nelson, Gary G. Grove, Stephen T. Massie, and Megan C. Twomey. "Interaction of Basal Foliage Removal and Late-Season Fungicide Applications in Management of Hop Powdery Mildew." Plant Disease 100, no. 6 (June 2016): 1153–60. http://dx.doi.org/10.1094/pdis-10-15-1232-re.
Full textAbstract:
Canopy management is an important aspect of control of powdery mildew diseases and may influence the intensity of fungicide applications required to suppress disease. In hop, powdery mildew (caused by Podosphaera macularis) is most damaging to cones when infection occurs during bloom and the juvenile stages of cone development. Experiments were conducted over 3 years to evaluate whether fungicide applications could be ceased after the most susceptible stages of cone development (late July) without unduly affecting crop yield and quality when disease pressure was moderated with varying levels of basal foliage removal. In experimental plots of ‘Galena’ hop, the incidence of leaves with powdery mildew was similar whether fungicides were ceased in late July or made in late August. Disease levels on leaves were unaffected by the intensity of basal foliage removal, whereas the intensity of basal foliage removal interacted with the duration of fungicide applications to affect disease levels on cones. Similar experiments conducted in large plots of ‘Tomahawk’ hop in a commercial hop yard similarly found no significant impact on disease levels on leaves from either the duration of fungicide applications or intensity of basal foliage removal. In contrast, on cones, application of fungicides into August had a modest, suppressive effect on powdery mildew. There was also some evidence that the level of powdery mildew on cones associated with fungicide treatment was influenced by the intensity of basal foliage removal. When fungicide applications ceased in late July, there was a progressive decrease in the incidence of cones with powdery mildew with increasing intensity of basal foliage removal. Removing basal foliage two to three times allowed fungicide applications to be terminated in late July rather than late August without diminishing disease control on cones, yield, or cone quality factors. Thus, this study further establishes that fungicide applications made during the early stages of hop cone development have the strongest effect on suppression of powdery mildew on cones. The additive effect of fungicide applications targeted to the periods of greatest cone susceptibility and canopy management to reduce disease favorability may obviate the need for fungicide applications later in the season. This appears to be a viable strategy in mature hop yards of certain cultivars when disease pressure is not excessively high.
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Glawe, Dean A., Gary G. Grove, and Mark Nelson. "First Report of Powdery Mildew of Gaillardia × grandiflora (Blanket Flower) Caused by Leveillula taurica in North America." Plant Health Progress 7, no. 1 (January 2006): 60. http://dx.doi.org/10.1094/php-2006-0112-01-br.
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During recent surveys of fieldgrown Gaillardia × grandiflora (Blanket flower) in Yakima Co., WA, a powdery mildew disease was observed on the cv. ‘Baby Cole.’ This report documents the occurrence of the powdery mildew fungus in question (Leveillula taurica (Lév.) G. Arnaud) on Gaillardia × grandiflora and provides information on disease symptomatology as well as features distinguishing this fungus from other powdery mildew pathogens of Gaillardia in North America. Accepted for publication 8 December 2005. Published 12 January 2006.
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Mykhailenko, S., and O. Melnyk. "The dynamics of powdery mildew development on pumpkins." Interdepartmental Thematic Scientific Collection of Plant Protection and Quarantine, no. 65 (December 20, 2019): 111–23. http://dx.doi.org/10.36495/1606-9773.2019.65.111-123.
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Goal. To determine the spread and development of powdery mildew on pumpkins in the Forest-Steppe of Ukraine.
Methods of investigation. The experiments were carried out in 2016—2018 biennium in the Right-Bank Forest Steppe of Ukraine (Khmelnytsky region) on the following varieties: common pumpkins — Ukrainskyi bahatoplidnyi, hull-less — Shtyriiskyi. Assessment of severity and spread of powdery mildew was carried out by conventional methods. The records were taken by visual method at 51, 73 and 89 stages (BBCH scale). Ten plants per plot were selected and spread and severity of the disease in percentage were determined.
Results of investigation. During the period of investigation, powdery mildew was observed on the pumpkins of both varieties annually. Its first sympthoms were noted at the 15—17 stage. According to the morphological and biometric features, the pathogen identified as Erysiphe cichoracearum (DC.) V.P. Heluta. In the varieties studied, powdery mildew was found with a non-significant difference in severity and spread. In 2016, the severity of powdery mildew on pumpkins of variety Ukrainskyi bahatoplidnyi varied in the range of 15.4—19.5%, disease spread — 45.1—49.6%, on variety Shtyriiskyi development was 13.3—17.5%, distribution — 46.2—48.1%. In 2017, we obtained the following results: the disease severity for common pumpkins was in the range 13.2—17.4%, disease spread — 42.8—46.7%, for hull-less pumpkins disease severity was 12.2—16.8%, disease spread — 41.7—45.3%. In 2018, severity of powdery mildew was higher than in previous years, accounting for 21.2—26.7% with spread 50.4—55.2% on common pumpkins, and 19.4—25.3% with spread 48.8—54.2% on hull-less pumpkins. The correlation analysis of the data showed that the closest correlation between the spread and the development of the disease was observed with the precipitation and GTC in June.
Conclusions. Dynamics of severity of powdery mildew during 2016—2018 years on common and hull-less pumpkins were studied. At stage of full ripening, the maximum rates of spread and severity of the disease were noted, which averaged 49.2—50.5% and 19.9—21.2% over the three years, respectively. No significant difference in the powdery mildew infection between common pumpkins (variety Ukrainskyi bahatoplidnyi) and hull-less pumpkins (variety Shtyriiskyi) was found. The defining conditions for the development of powdery mildew on pumpkins are the weather conditions in June, most notably the presence of increased moisture during this period.
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Gadoury, David M., Robert C. Seem, Andrea Ficke, and Wayne F. Wilcox. "Ontogenic Resistance to Powdery Mildew in Grape Berries." Phytopathology® 93, no. 5 (May 2003): 547–55. http://dx.doi.org/10.1094/phyto.2003.93.5.547.
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Berries of Vitis vinifera are reported to be susceptible to infection by Uncinula necator until soluble solids levels (brix) reach 8%, and established colonies are reported to sporulate until brix reach 15%. However, our analysis of disease progress on fruit of selected V. vinifera cultivars indicated that severity became asymptotic several weeks earlier in fruit development. When mildew-free fruit clusters of V. vinifera ‘Chardonnay’, ‘Riesling’, ‘Gewürztraminer’, and ‘Pinot Noir’ were inoculated at stages ranging from prebloom to 6 weeks postbloom, only fruit inoculated within 2 weeks of bloom developed severe powdery mildew. Substantial ontogenic resistance to infection was expressed in fruit nearly 6 weeks before fruit brix reached 8% and over 2 months before they reached 15%. Rachises of ‘Chardonnay’ and ‘Riesling’ fruit clusters developed severe powdery mildew when inoculated at bloom, and disease increased steadily over the next 60 days. The rachis of fruit clusters inoculated 31 days after bloom developed only trace levels of powdery mildew. Berry weight of all four cultivars at harvest was reduced when fruit clusters were inoculated at bloom or 16 days postbloom, primarily by splitting, rotting, and dehydration of mildewed berries, but the weight of later-inoculated berries was not reduced. Inoculation of berries just as ontogenic resistance increased markedly, approximately 3 to 4 weeks postbloom, resulted in the development of inconspicuous, diffuse, non-sporulating mildew colonies on berries, sometimes associated with a network of necrotic epidermal cells. Rather than a protracted and relatively static period of berry susceptibility lasting 3 months, fruit of V. vinifera appear to acquire ontogenic resistance rapidly after fruit set. A refocusing of disease management on this critical period of high fruit susceptibility should greatly improve the efficacy of fungicides directed against powdery mildew.
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Troch, V., K. Audenaert, A. Vanheule, B. Bekaert, M. Höfte, and G. Haesaert. "Evaluation of Resistance to Powdery Mildew in Triticale Seedlings and Adult Plants." Plant Disease 97, no. 3 (March 2013): 410–17. http://dx.doi.org/10.1094/pdis-02-12-0161-re.
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Triticale (×Triticosecale) is the intergeneric hybrid between the female parent wheat and the male parent rye. With the expansion of the triticale growing area, powdery mildew emerged on this new host and has become a significant disease on triticale. Recent research demonstrated that this “new” powdery mildew on triticale has emerged through a host range expansion of powdery mildew of wheat. Moreover, this expansion occurred recently and multiple times at different locations in Europe. An effective and environmentally sensitive approach to controlling powdery mildew involves breeding crop plants for resistance. The main goal of this study was to identify the presence of powdery mildew resistance in commercial triticale cultivars. First, the avirulence (AVR) genes and gene complexity carried by this new powdery mildew population on triticale were characterized. Virulence was identified for all the resistance genes evaluated in the present study, and virulence frequencies higher than 50% were recorded on the genes Pm3f, Pm5b, Pm6, Pm7, Pm8, and Pm17. Using molecular markers, the presence of resistance genes Pm3f and Pm17 was identified in certain triticale cultivars. The triticale cultivars were also evaluated for the presence of quantitative resistance at adult plant growth stages in a 2-year field experiment. Despite the high disease pressure, cultivars highly resistant at the adult-plant growth stages were identified. Because ‘Grenado’ also showed effective race-specific resistance, this cultivar could be of high value for breeding for durable resistance to powdery mildew. Altogether, this study reveals valuable information on the presence of powdery mildew resistance in commercial triticale cultivars, which can be used in breeding programs in triticale. Additionally, this study underscores the need to broaden the base of powdery mildew resistance in triticale through introgression and deployment of new sources of mildew resistance, including quantitative resistance.
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Pietrusińska, Aleksandra, and Anna Tratwal. "Characteristics of powdery mildew and its importance for wheat grown in Poland." Plant Protection Science 56, No. 3 (June 11, 2020): 141–53. http://dx.doi.org/10.17221/99/2019-pps.
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Powdery mildew of grasses and cereals (Blumeria graminis) is a fungal plant disease which is caused by species of fungi from the Erysiphaceae order. B. graminis is a biotrophic parasite, biologically diverse parasite with a high degree of specialization in certain host species and with numerous physiological breeds adapted to different varieties of a particular host species. In Poland, powdery mildew of cereals and grasses is recorded every year, and its greatest intensity is in south-eastern and south-western regions. The degree of infestation by B. graminis varies every year. This means that the disease occurs every year, in greater or lesser severity. Therefore, it requires monitoring (harmfulness thresholds) and chemical control practically in every vegetation season. Nowadays, an important role is played by immunological breeding. In breeding programs, resistance genes from wild crop forms, primitive and indigenous varieties are an effective tool. The introduction of effective resistance genes into cultivated varieties is a common procedure used in breeding program.<br />The aim of this study was to describe the fungal disease of plants from the group of powdery mildews caused by <br /> B. graminis as an overview.
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Krahl, Kimberly H. "Screening for Powdery Mildew Resistance in Pulmonaria." HortScience 39, no. 1 (February 2004): 161–62. http://dx.doi.org/10.21273/hortsci.39.1.161.
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A screening technique was developed for studying resistance to powdery mildew disease in 25 diverse Pulmonaria L. species and cultivars. Healthy Pulmonaria plants were inoculated by drawing naturally infected leaves of P. angustifolia `Blaues Meer' across the abaxial surface of three healthy, mature leaves per test plant. Inoculated leaves were rated for powdery mildew infection using a scale of 0-5, where 0 = no visible sign of infection, 1 = 1% to 20%; 2 = 20% to 40%; 3 = 40% to 60%; 4 = 60% to 80%; 5 = 80% to 100% of leaf surface covered with white mycelial growth. Each genotype was inoculated and evaluated four times. The data revealed a wide and continuous range of variability for powdery mildew disease incidence in the 25 lungwort genotypes that may be indicative of quantitative resistance. The majority of lungwort genotypes exhibited low levels of resistance to powdery mildew. Four cultivars (P. hybrid `Spilled Milk', P. hybrid `Excaliber', P. rubra `Redstart', and P. rubra `David Ward') and one selection (P. longifolia ssp. cevennensis) exhibited high levels of resistance to powdery mildew. Since Pulmonaria species intercross readily, these genotypes may be useful in the future development of new powdery mildew resistant Pulmonaria cultivars.
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Heick, Thies Marten, Anne Lisbet Hansen, Annemarie Fejer Justesen, and Lise Nistrup Jørgensen. "QoI Resistance in Sugar Beet Powdery Mildew (Erysiphe betae) in Scandinavia." Plant Health Progress 20, no. 3 (January 1, 2019): 179. http://dx.doi.org/10.1094/php-01-19-0004-br.
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Powdery mildew caused by Erysiphe betae is one of the major fungal diseases in sugar beet in Denmark and Sweden. Frequent applications of fungicides mitigate the risk of powdery mildew epidemics and, consequently, reduce yield losses conferred by the disease. So far, mixtures of quinone outside inhibitors (QoIs) and triazoles have provided good efficacy against E. betae in field trials and common farming practice. However, development of fungicide resistance is a real risk, because only a limited number of active ingredients are available for the control of powdery mildew in sugar beet, and several other active ingredients are expected to be banned following reevaluation when the most recent European Union legislation is implemented. The G143A mutation associated with QoI resistance has been previously found in the United States. In this brief, its presence in Europe is reported for the first time. The current finding strongly encourages the adoption of anti-resistance strategies that minimize the spread of QoI resistance in sugar beet powdery mildew. Those strategies should be based on integrated pest management measures, including disease monitoring, the use of resistant cultivars, and the use of biological products. A sole reliance on QoI fungicides for sugar beet powdery mildew control should be avoided.
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Ma, Huiqin, Yuanshu Jing, Wenjiang Huang, Yue Shi, Yingying Dong, Jingcheng Zhang, and Linyi Liu. "Integrating Early Growth Information to Monitor Winter Wheat Powdery Mildew Using Multi-Temporal Landsat-8 Imagery." Sensors 18, no. 10 (September 30, 2018): 3290. http://dx.doi.org/10.3390/s18103290.
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Powdery mildew is one of the dominant diseases in winter wheat. The accurate monitoring of powdery mildew is important for crop management and production. Satellite-based remote sensing monitoring has been proven as an efficient tool for regional disease detection and monitoring. However, the information provided by single-date satellite scene is hard to achieve acceptable accuracy for powdery mildew disease, and incorporation of early period contextual information of winter wheat can improve this situation. In this study, a multi-temporal satellite data based powdery mildew detecting approach had been developed for regional disease mapping. Firstly, the Lansat-8 scenes that covered six winter wheat growth periods (expressed in chronological order as periods 1 to 6) were collected to calculate typical vegetation indices (VIs), which include disease water stress index (DSWI), optimized soil adjusted vegetation index (OSAVI), shortwave infrared water stress index (SIWSI), and triangular vegetation index (TVI). A multi-temporal VIs-based k-nearest neighbors (KNN) approach was then developed to produce the regional disease distribution. Meanwhile, a backward stepwise elimination method was used to confirm the optimal multi-temporal combination for KNN monitoring model. A classification and regression tree (CART) and back propagation neural networks (BPNN) approaches were used for comparison and validation of initial results. VIs of all periods except 1 and 3 provided the best multi-temporal data set for winter wheat powdery mildew monitoring. Compared with the traditional single-date (period 6) image, the multi-temporal images based KNN approach provided more disease information during the disease development, and had an accuracy of 84.6%. Meanwhile, the accuracy of the proposed approach had 11.5% and 3.8% higher than the multi-temporal images-based CART and BPNN models’, respectively. These results suggest that the use of satellite images for early critical disease infection periods is essential for improving the accuracy of monitoring models. Additionally, satellite imagery also assists in monitoring powdery mildew in late wheat growth periods.
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Bai, B., Z. H. He, M. A. Asad, C. X. Lan, Y. Zhang, X. C. Xia, J. Yan, X. M. Chen, and C. S. Wang. "Pyramiding adult-plant powdery mildew resistance QTLs in bread wheat." Crop and Pasture Science 63, no. 7 (2012): 606. http://dx.doi.org/10.1071/cp12183.
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Pyramiding of quantitative trait loci (QTLs) can be an effective approach for developing durable resistance to powdery mildew in wheat (Triticum aestivum L.). The Chinese wheat cultivars Bainong 64 and Lumai 21, with outstanding agronomic traits, possess four and three QTLs, respectively, for adult-plant resistance (APR) to powdery mildew. To achieve optimal durable resistance, 21 F6 lines combining two–five powdery mildew APR QTLs were developed from the cross Bainong 64/Lumai 21 using a modified pedigree selection. These lines were planted in a randomised complete block design with two replicates in Beijing during the 2009–10 and 2010–11 cropping seasons, and were evaluated for powdery mildew response using the highly virulent Blumeria graminis f. sp. tritici isolate E20. Based on the phenotypic data of both maximum disease severity (MDS) and area under the disease progress curve (AUDPC), analysis of variance indicated that there were highly significant effects of QTL combinations on reducing powdery mildew MDS and AUDPC. Six pyramided QTL combinations possessing QPm.caas-1A and QPm.caas-4DL in common along with one or more of the others expressed better APR to powdery mildew than the more resistant parent, Bainong 64. Thus, pyramiding these two QTLs with one or more of QPm.caas-2BS, QPm.caas-2BL, and QPm.caas-2DL from Lumai 21 could be a desirable strategy to breed cultivars with high levels of durable resistance to powdery mildew. Experienced breeders with a good knowledge of minor genes can achieve APR by phenotypic selection, and selection by molecular markers will still require uniform field testing for powdery mildew and disease phenotype to validate the resistance. These results provided very useful information for pyramiding APR QTLs in wheat breeding programs.
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Liang, S. S., K. Suenaga, Z. H. He, Z. L. Wang, H. Y. Liu, D. S. Wang, R. P. Singh, P. Sourdille, and X. C. Xia. "Quantitative Trait Loci Mapping for Adult-Plant Resistance to Powdery Mildew in Bread Wheat." Phytopathology® 96, no. 7 (July 2006): 784–89. http://dx.doi.org/10.1094/phyto-96-0784.
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Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a major disease to wheat (Triticum aestivum) worldwide. Use of adult-plant resistance (APR) is an effective method to develop wheat cultivars with durable resistance to powdery mildew. In the present study, 432 molecular markers were used to map quantitative trait loci (QTL) for APR to powdery mildew in a doubled haploid (DH) population with 107 lines derived from the cross Fukuho-komugi × Oligoculm. Field trials were conducted in Beijing and Anyang, China during 2003-2004 and 2004-2005 cropping seasons, respectively. The DH lines were planted in a randomized complete block design with three replicates. Artificial inoculation was carried out in Beijing with highly virulent isolate E20 of B. graminis f. sp. tritici and the powdery mildew severity on penultimate leaf was evaluated four times, and the maximum disease severity (MDS) on penultimate leaf was investigated in Anyang under natural inoculation in May 2004 and 2005. The heritability of resistance to powdery mildew for MDS in 2 years and two locations ranged from 0.82 to 0.93, while the heritability for area under the disease progress curve was between 0.84 and 0.91. With the method of composite interval mapping, four QTL for APR to powdery mildew were detected on chromosomes 1AS, 2BL, 4BL, and 7DS, explaining 5.7 to 26.6% of the phenotypic variance. Three QTL on chromosomes 1AS, 2BL, and 7DS were derived from the female, Fukuho-komugi, while the one on chromosome 4BL was from the male, Oligoculm. The QTL on chromosome 1AS showed high genetic effect on powdery mildew resistance, accounting for 19.5 to 26.6% of phenotypic variance across two environments. The QTL on 7DS associated with the locus Lr34/Yr18, flanked by microsatellite Xgwm295.1 and Ltn (leaf tip necrosis). These results will benefit for improving powdery mildew resistance in wheat breeding programs.
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Beany, A. H., K. Pernezny, P. J. Stoffella, N. Havranek, and J. Sanchez. "DOWNY AND POWDERY MILDEW MANAGEMENT FOR WINTER SQUASH." HortScience 40, no. 3 (June 2005): 886c—886. http://dx.doi.org/10.21273/hortsci.40.3.886c.
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Control of downy (Pseudoperonospora cubensis) and powdery mildew [(Podosphoera xanthii (Sphaerotheca fuliginea)] on `Sweet Dumpling' winter squash (Cucurbita maxima) was evaluated at the University of Florida, IFAS, Indian River Research and Education Center (IRREC) in Fort Pierce, Florida during Spring 2004. Seven foliar spray fungicide treatments were evaluated against an untreated control. Powdery and downy mildew ratings (estimated percentage of foliage damage) and marketable yields (mt/ha) were measured. Plants in the untreated plots had significantly higher powdery and downy mildew ratings. All fungicide treatments reduced powdery mildew on adaxial leaf surfaces. Downy mildew appeared unusually late in the crop season and all fungicide treatments significantly reduced it. There were no significant differences among treatments for marketable yield. Although the level of disease occurrence was not sufficient to reduce yields, each foliar spray treatment significantly reduced powdery and downy mildew.
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Kousik, Chandrasekar S., Amnon Levi, Kai-Shu Ling, and W. Patrick Wechter. "Potential Sources of Resistance to Cucurbit Powdery Mildew in U.S. Plant Introductions of Bottle Gourd." HortScience 43, no. 5 (August 2008): 1359–64. http://dx.doi.org/10.21273/hortsci.43.5.1359.
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Powdery mildew (Podosphaera xanthii) can cause severe damage to cucurbit crops grown in open fields and greenhouses. In recent years, there has been an increased interest in the United States in grafting watermelon plants onto various cucurbit rootstocks. Bottle gourd plants (Lagenaria siceraria) are being used throughout the world as rootstocks for grafting watermelon. Although gourd plants are beneficial, they may still be susceptible hosts to various soilborne and foliar diseases. Bottle gourd plant introductions (PI) resistant to diseases and pests can be a valuable source of germplasm in rootstock breeding programs. We evaluated 234 U.S. PIs of L. siceraria for tolerance to powdery mildew in two greenhouse tests. Young seedlings were inoculated by dusting powdery mildew spores of melon race 1 on the cotyledons. Plants were rated 2 weeks after inoculation using a 1 to 9 scale of increasing disease severity. Although none of the L. siceraria PIs were immune to powdery mildew, several PIs had significantly lower levels of powdery mildew severity compared with susceptible watermelon cultivar Mickey Lee. The experiment was repeated with 26 select PIs on whole seedlings and cotyledon disks. Significant variability in the level of resistance to powdery mildew on plants within PI was observed. Moderate resistance in several PIs to powdery mildew was confirmed. PI 271353 had consistently lower ratings in the various tests and can be considered the most resistant to P. xanthii race 1 among the L. siceraria accessions evaluated in this study. A few other PIs with moderate resistance to powdery mildew included PI 271357, PI 381840, and PI 273663. These results suggest that novel sources of resistance could be developed by careful selection and screening of several of the PIs with moderate resistance described in our study.
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Wu, Xianxin, Qiang Bian, Yue Gao, Xinyu Ni, Yanqiu Sun, Yuanhu Xuan, Yuanyin Cao, and Tianya Li. "Evaluation of resistance to powdery mildew and identification of resistance genes in wheat cultivars." PeerJ 9 (January 11, 2021): e10425. http://dx.doi.org/10.7717/peerj.10425.
Full textAbstract:
Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici (Bgt), is a serious disease of wheat worldwide that can cause significant yield losses. Growing resistant cultivars is the most cost-effective and eco-soundly strategy to manage the disease. Therefore, a high breeding priority is to identify genes that can be readily used either singly or in combination for effective resistance to powdery mildew and also in combination with genes for resistance to other diseases. Yunnan Province, with complex and diverse ecological environments and climates, is one of the main wheat growing regions in China. This region provides initial inoculum for starting epidemics of wheat powdery mildew in the region and other regions and thus, plays a key role in the regional and large-scale epidemics of the disease throughout China. The objectives of this study were to evaluate seedling resistance of 69 main wheat cultivars to powdery mildew and to determine the presence of resistance genes Pm3, Pm8, Pm13, Pm16, and Pm21in these cultivars using gene specific DNA markers. Evaluation of 69 wheat cultivars with six Bgt isolates showed that only four cultivars were resistant to all tested isolates, indicating that the overall level of powdery mildew resistance of Yunnan wheat cultivars is inadequate. The molecular marker results showed that 27 cultivars likely have at least one of these genes. Six cultivars were found likely to have Pm3,18 likely to have Pm8,5 likely to have Pm16,and 3 likely to have Pm21. No cultivar was found to carry Pm13. The information on the presence of the Pmresistance genes in Yunnan wheat cultivars can be used in future wheat disease breeding programs. In particular, cultivars carrying Pm21, which is effective against all Bgtraces in China, should be pyramided with other effective genes to developing new cultivars with durable resistance to powdery mildew.
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Wu, Xianxin, Qiang Bian, Yue Gao, Xinyu Ni, Yanqiu Sun, Yuanhu Xuan, Yuanyin Cao, and Tianya Li. "Evaluation of resistance to powdery mildew and identification of resistance genes in wheat cultivars." PeerJ 9 (January 11, 2021): e10425. http://dx.doi.org/10.7717/peerj.10425.
Full textAbstract:
Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici (Bgt), is a serious disease of wheat worldwide that can cause significant yield losses. Growing resistant cultivars is the most cost-effective and eco-soundly strategy to manage the disease. Therefore, a high breeding priority is to identify genes that can be readily used either singly or in combination for effective resistance to powdery mildew and also in combination with genes for resistance to other diseases. Yunnan Province, with complex and diverse ecological environments and climates, is one of the main wheat growing regions in China. This region provides initial inoculum for starting epidemics of wheat powdery mildew in the region and other regions and thus, plays a key role in the regional and large-scale epidemics of the disease throughout China. The objectives of this study were to evaluate seedling resistance of 69 main wheat cultivars to powdery mildew and to determine the presence of resistance genes Pm3, Pm8, Pm13, Pm16, and Pm21in these cultivars using gene specific DNA markers. Evaluation of 69 wheat cultivars with six Bgt isolates showed that only four cultivars were resistant to all tested isolates, indicating that the overall level of powdery mildew resistance of Yunnan wheat cultivars is inadequate. The molecular marker results showed that 27 cultivars likely have at least one of these genes. Six cultivars were found likely to have Pm3,18 likely to have Pm8,5 likely to have Pm16,and 3 likely to have Pm21. No cultivar was found to carry Pm13. The information on the presence of the Pmresistance genes in Yunnan wheat cultivars can be used in future wheat disease breeding programs. In particular, cultivars carrying Pm21, which is effective against all Bgtraces in China, should be pyramided with other effective genes to developing new cultivars with durable resistance to powdery mildew.
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Barker, Hilary L., Denise Smith, Glen Stanosz, and Richard L. Lindroth. "Host genetics and environment shape fungal pathogen incidence on a foundation forest tree species, Populus tremuloides." Canadian Journal of Forest Research 46, no. 9 (September 2016): 1167–72. http://dx.doi.org/10.1139/cjfr-2016-0116.
Full textAbstract:
Diseases can markedly alter the ecological and economic value of poplars. To better understand poplar–pathogen interactions, we investigated the independent and interactive effects of tree genotype, soil nutrient limitation, and interspecific competition on incidence of powdery mildew (caused by the fungal obligate pathogen Erysiphe adunca (Wallr.) Fr., 1829) in a foundation tree species, trembling aspen (Populus tremuloides Michx.). We established a common garden of potted aspen saplings, incorporating five tree genotypes, two levels of soil nutrients (low and high), and two levels of competition (with and without grass). We then surveyed natural incidence of powdery mildew and aspen vigor (i.e., growth). Incidence of powdery mildew varied among aspen genotypes, and variance in incidence shifted among environments in which the trees were grown. Added soil nutrients increased powdery mildew incidence on aspen, whereas grass competition had the opposite effect. Interestingly, grass competition either enhanced or dampened the variance in incidence of powdery mildew among tree genotypes, depending on soil nutrient levels. In addition, powdery mildew incidence was positively related to tree vigor. Our findings reveal strong genetic, environmental, and genetic×environmental effects of disease on a foundation tree species and that particular environments can either enhance or diminish variation in responses among tree genotypes.
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Singh, Kuldeep, Satish Kumar, and Pawan Kaur. "Detection of Powdery Mildew Disease of Beans in India : A Review." Oriental journal of computer science and technology 9, no. 3 (December 25, 2016): 226–34. http://dx.doi.org/10.13005/ojcst/09.03.08.
Full textAbstract:
Powdery mildew disease of beans in India causes major economic losses in agriculture. For sustainable agriculture detection and identification of diseases in plants is very important. In this review, we are trying to identify the powdery mildew disease of beans crop by using some image processing and pattern recognition techniques and comparing with molecular and spectroscopic techniques. Early information on crop health and disease detection can facilitate the control of diseases through proper management strategies. The present review recognizes the need for developing a rapid, cost-effective, and reliable health monitoring techniques that would facilitate advancements in agriculture. These technologies include image processing and pattern recognition based plant disease detection methods
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Athira, K., N. Ragupathi, and T. Raguchander. "Morphological characterization of Ampelomyces spp., a hyperparasite of Bhendi (Abelmoschus esculentus (L.) Moench) powdery mildew." Journal of Applied and Natural Science 9, no. 4 (December 1, 2017): 1954–57. http://dx.doi.org/10.31018/jans.v9i4.1471.
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Ampelomyces is a naturally occurring hyperparasite on powdery mildews. Survey was conducted in major bhendi (Abelmoschus esculentus (L.) Moench) growing districts of Tamil Nadu during June 2014 to assess the incidence of powdery mildew and to collect different isolates of Ampelomyces spp. The results of the survey revealed that the disease incidence ranged from 15.54 to 63.45 %. Ten isolates of Ampelomyces spp. were collect-ed from surveyed areas of powdery mildew. Isolation of Ampelomyces spp. was done from powdery mildew infected bhendi leaf parasitized by Ampelomyces spp. using tissue segment method. All the isolates were identified by their morphological characters. The colour of the colonies in various medium was brownish black to greenish white. Most of the isolates showed radial and fluffy growth pattern with raised growth. The pycnidia of different isolates of Ampelomyces varied in their shape and were mostly ovoid, ellipsoid, cylindrical, pyriform to globose in shape. The size of pycnidia varied from 29.2-72.5×22.4-43.1 μm. The number of pycnidia was found to be more in isolates viz., TNAU-AQ101 and TNAU-AQ103. Pycnidiospores are hyaline, unicellular and guttulate in shape. The pycnidial production was higher in TNAU-AQ101 and TNAU-AQ103. Application of agrochemicals is one of the oldest and most effective methods to manage powdery mildew disease. However, incessant use of these agrochemicals has many demerits such as development of resistance to pathogens, residual toxicity and environmental pollution. Hence, search for an alternative means for disease management is envisaged. The genus Ampelomyces are the major antagonists as an alternative of Erysiphales fungi being a significant group of phytopathogens.
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Baysal-Gurel, Fulya, and Ravi Bika. "Management of Powdery Mildew on Ninebark Using Sanitizers, Biorational Products, and Fungicides." HortScience 56, no. 5 (May 2021): 532–37. http://dx.doi.org/10.21273/hortsci15691-21.
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Ninebark (Physocarpus opulifolius) is a popular ornamental shrub and considered a hardy and tough plant that can thrive in different environmental conditions and resist diseases. However, powdery mildew, caused by Podosphaera physocarpi, can severelyaffect ninebark, deteriorating the ornamental value and making them unmarketable. Only a few studies have been done in managing powdery mildew of ninebark. The current study focuses on evaluating and identifying effective products (sanitizers, biorational products, and fungicides) for the management of powdery mildew disease of ninebark. A total of 12 treatments, including nontreated control, were studied. The experiment was arranged in randomized complete block design with four-single ‘Mindia Coppertina®’ ninebark plant per treatment and repeated twice. Powdery mildew disease severity, growth parameters, and phytotoxicity were assessed in the study. All treatments significantly reduced the powdery mildew disease severity and disease progress [area under disease progress curve (AUDPC)] compared with the nontreated control. The treatments, such as azoxystrobin + benzovindiflupyr at 0.17 and 0.23 g·L–1 total active ingredients (a.i.) applied, chlorothalonil + propiconazole at 1.12 mL·L–1 total a.i. applied, azoxystrobin + tebuconazole at 0.11 and 0.16 g·L–1 total a.i. applied, and giant knotweed extract [Reynoutria sachalinensis (0.5 mL·L–1 total a.i. applied)] were the most effective treatments in reducing disease severity and disease progress in both trials. The treatments had no significant effects on the plant growth parameters such as height and width. In Expt. 2, azoxystrobin + benzovindiflupyr and hydrogen peroxide + peroxyacetic acid treated plants showed the low level of phytotoxic symptoms. The phytotoxicity of these two treatments in Expt. 2 could be related to higher environmental temperature during the experimental period.
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Gent, David H., Mark E. Nelson, Gary G. Grove, Walter F. Mahaffee, William W. Turechek, and Joanna L. Woods. "Association of Spring Pruning Practices with Severity of Powdery Mildew and Downy Mildew on Hop." Plant Disease 96, no. 9 (September 2012): 1343–51. http://dx.doi.org/10.1094/pdis-01-12-0084-re.
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Downy mildew (caused by Pseudoperonospora humuli) and powdery mildew (caused by Podosphaera macularis) are important diseases of hop in the Pacific Northwest United States, and cultural practices may affect the severity of both diseases. The association of spring pruning quality and timing with severity of downy mildew and powdery mildew was assessed through analysis of survey data collected from commercial hop yards in Oregon and Washington. Among 149 hop yards surveyed, the most common pruning method was chemical desiccation (48% of yards), mechanical pruning (23%), or a combination of these practices (15%). The quality of pruning was assessed using a three-category ordinal scale (“excellent”, “moderate”, or “poor”) based on the amount of foliage remaining on plants following pruning. Excellent pruning quality was attained more often in yards pruned twice (74.6 to 82.1% of yards) versus once (33.8% of yards), independent of pruning method. Seasonal severity of downy mildew in Oregon increased approximately twofold with reduction in pruning quality from excellent to moderate to poor. Pruning quality was not significantly related to levels of powdery mildew on leaves or cones in Oregon. Under more severe disease pressure in Washington, however, seasonal severity of powdery mildew on leaves and the incidence of cones with powdery mildew were significantly greater in yards that had poor pruning compared with excellent pruning. Moreover, yards that had excellent pruning quality received, on average, 1.1 to 1.5 fewer fungicide applications per season for downy mildew or powdery mildew compared with yards that had moderate or poor pruning quality. This savings was associated with delayed initiation of the first application by 7.5 to 14.2 days in yards with excellent pruning quality. Replicated experiments in commercial yards in Oregon quantified the effect of delaying pruning timing 5 to 21 days compared with growers' standard practices on the diseases and yield. Downy mildew suppression by delayed pruning was dependent on cultivar and year of sampling, being significantly reduced fivefold only in ‘Willamette’ in 2007. Severity of powdery mildew and cone yield was similar between plots that received the delayed or standard pruning timing treatments. Collectively, these studies emphasize that early spring sanitation measures are associated with reduced primary inoculum and are critically important for managing both downy mildew and powdery mildew. A savings of at least one fungicide application per year appears achievable when spring pruning is conducted thoroughly and slightly delayed compared with growers' current practices.
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Kamel, Said M., Mohamed M. I. Afifi, Fathia S. El-shoraky, and Mohamad M. El-Sawy. "Fulvic Acid: A Tool for Controlling Powdery and Downy Mildews in Cucumber Plants." International Journal of Phytopathology 3, no. 2 (August 25, 2014): 101–8. http://dx.doi.org/10.33687/phytopath.003.02.0866.
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A greenhouse experiment was carried out on cucumber cultivar DP-164 during the seasons 2012-2013 to evaluate the efficacy of three concentrations of fulvic acid (FA) to control downy and powdery mildew diseases compared with the recommended fungicides and their effects on plant growth, chlorophyll content and yield of cucumber plants. Results revealed that all FA concentrations significantly reduced disease severity of both diseases. The highest reduction in disease severity of downy mildew was recorded using 75 ppm of FA, which was more effective than the recommended fungicide. The significant effect of inhibition of powdery mildew diseases increased gradually with increased FA concentration. At the same time, the reduction of diseases severity was greater than or equal to the recommended fungicides. Foliar application of FA concentrations and Ridomil fungicide increased significantly all morphological characters. Sumi-8 fungicide increased the morphological characters except plant height, dry weight/ plant and leaves number/ plant. The yield components (weight of fruits and mean of fruit weight /plant) recorded the same values with all FA concentrations. Fulvic acid had direct effect on soil microbiology by increasing plant exudates, which enhanced the activity of microorganism. Fulvic acid at 150ppm showed the highest increase in dehydrogenase and nitrogenase activity. This study revealed that the foliar application of FA improved plant growth and yield quantity and quality as well as controlling powdery and downy mildews of cucumber plants. Additionally, FA has the advantage as effective and environmental friendly agent
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Conner, R. L., A. D. Kuzyk, and H. Su. "Impact of powdery mildew on the yield of soft white spring wheat cultivars." Canadian Journal of Plant Science 83, no. 4 (October 1, 2003): 725–28. http://dx.doi.org/10.4141/p03-043.
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The effect of powdery mildew (Blumeria graminis f. sp. tritici) on the grain yield and protein content of one susceptible, Springfield, and three moderately resistant cultivars, Fielder, AC Reed and AC Nanda, of soft white spring wheat (Triticum aestivum) was examined at two field locations near Lethbridge and Vauxhall, Alberta, in 1999 and 2000. At the start of heading, powdery mildew development was suppressed in half of the plots of each cultivar by a single spray application of the fungicide Tilt (propiconazole). Severe powdery mildew infection of the susceptible cultivar Springfield resulted in yield reductions ranging from 11.4 to 19.9%. The grain yield of the moderately resistant cultivar Fielder was significantly reduced at both sites in 1999 by 7.6–10.5% while AC Reed suffered a significant yield loss (7.6–9.1%) at Lethbridge in both years. The moderately resistant cultivar AC Nanda consistently had the lowest powdery mildew ratings and its yield was unaffected by the disease. A single fungicide application prevented disease buildup on the moderately resistant cultivars, but not on Springfield. The grain protein content of the moderately resistant cultivars was unaffected by powdery mildew, but it decreased in Springfield by 0.6–0.7%. Key words: Powdery mildew, Propiconazole, Blumeria graminis f. sp. tritici, wheat, Triticum aestivum, resistance
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Balaz, Jelica, and Tatjana Knezevic. "Efficiency of more recent fungicides in control of apple scab and powdery mildew." Pesticidi 18, no. 3 (2003): 175–85. http://dx.doi.org/10.2298/pif0303175b.
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Apple scab (V. inaequalis) and powdery mildew (P. leucotricha) are most economicaly important diseases of apple. Chemical measures are of the highest importance in controlling these diseases. There is great number of fungicides on the market. Fungicide choice and time of application depend upon mechanism of their action. Experiments on controlling apple scab and powdery mildew are carried out in 1998/99 and 2002. in different locations in Vojvodina. According to the obtained results the highest efficacy in the control of apple scab and powdery mildew have performed pesticides from strobilurin group (Stroby-kresoxim-methyl and Zato 50 WG-trifloxystrobin)as well as fungicides belonging to the new group of fungicides (Clarinet). In the disease control of the apple high efficacy have also performed DMI fungicides such as Score 250-EC (in control of apple scab). Topas-lOOE and Webeton (in control of powder) mildew). Lower efficacy have performed fungicides with preventive activity such as combination of Venturin S-50+Cosan. Unpublished data from previous studies (1995-1997) of the fungicide Chorus (cyprodinil) biological efficacy also suggested that this new generation fungicide from anylopyrimidin group showed better efficacy than fungicides belonging to former DMI fungicides, as well as contact ones.