scholarly journals 012 Management of Powdery Mildew on Flowering Dogwood with Soybean Oil

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 390A-390
Author(s):  
Dennis E. Deyton ◽  
Carl E. Sams ◽  
Mark T. Windham
Keyword(s):  
Powdery Mildew ◽  
Soybean Oil ◽  
Disease Severity ◽  
Net Photosynthesis ◽  
Height Growth ◽  
Block Designs ◽  
Flowering Dogwood ◽  
Repeated Applications ◽  
Heavy Infestation

Field-grown dogwood trees in a commercial nursery were sprayed with 0%, 1%, or 2% soybean oil emulsified with Latron B-1956 at 2-week intervals from 10 June until 19 Aug. 1998. In 1999, dogwood trees were sprayed with 0%, 1%, 1.5%, 2%, or 2.5% emulsified soybean oil at 2-week intervals from 22 June until 26 Aug. The trials had treatments arranged in randomized complete-block designs with eight trees per block and six and four replications in 1998 and 1999, respectively. Disease severity of powdery mildew was estimated using the following scale: 0 = healthy, 1 < 2%, 2 < 10%, 3 < 25%, 4 < 50%, 5 > 50%, and 6 = 100% of foliage with symptoms or signs of powdery mildew. In 1998, trees sprayed with soybean oil had higher net photosynthesis rates and more caliper and height growth than control trees. Untreated trees and ≈25% of foliage infected with powdery mildew on 8 July, while trees sprayed with 1% or 2% soybean oil had about 2% of leaves infected. In 1999, the powdery mildew was already present on foliage (wet spring) when the first application of oil was made. Repeated sprays of soybean oil did not reduce the incidence of powdery mildew. Thus, soybean oil appeared to provide protective control of powdery mildew but not curative control of a heavy infestation of the fungi. Photosynthesis was increased by soybean oil for the first month of spraying in 1999, but did not differ after that. Repeated applications of even the high rates of oil did not cause phytotoxicity.

scholarly journals Management of Powdery Mildew on Flowering Dogwood with Soybean Oil

2011 ◽  
Vol 29 (4) ◽  
pp. 185-192
Author(s):  
Dennis E. Deyton ◽  
Carl E. Sams ◽  
Adrianna L. Cannon ◽  
John C. Cummins ◽  
Mark T. Windham
Keyword(s):  
Growth Rate ◽  
Powdery Mildew ◽  
Soybean Oil ◽  
Net Photosynthetic Rate ◽  
Soy Oil ◽  
Food Grade ◽  
Flowering Dogwood ◽  
Greenhouse Trial ◽  
Field Nursery ◽  
Oil Residue

Abstract Soybean oil formulations developed in our laboratory were evaluated for control of powdery mildew on flowering dogwood Cornus florida. In a preliminary trial in a field nursery, two formulations, TNsoy1 and TNsoy2 [0, 1 or 2% (v/v)], were applied to field-grown flowering dogwood at 2 wk intervals from June 10 until August 19. Soy oil-treated trees had less powdery mildew, higher net photosynthetic rate and growth rate than unsprayed trees, without apparent phytotoxicity. Leaves sprayed with Banner MAXX had less powdery mildew and higher photosynthetic rates than oil treated leaves. These same treatments applied the next year under more frequent rain showers did not provide satisfactory control. Newer soybean oil formulations using natural or food grade emulsifiers, were compared to three commercial botanical oil formulations and to SunSpray Ultra Fine Oil in greenhouse trials. All oil formulations provided some protective and eradicative control of powdery mildew. Photosynthesis of oil treated leaves was usually depressed, compared to controls, for several days but recovered. In greenhouse trials where the oil was not washed off by rain or irrigation, the oil residue was visible on leaves, reduced powdery mildew severity, and depressed photosynthesis for several weeks. In a second greenhouse trial, soybean oil formulations provided greater control if applied after rather than before initial inoculation.

In Vitro Establishment of Powdery Mildew (Microsphaera pulchra) on Microshoots of Flowering Dogwood

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 506a-506
Author(s):  
L.A. Klein ◽  
M.T. Windham ◽  
R.N. Trigiano
Keyword(s):  
Powdery Mildew ◽  
Woody Plant ◽  
Infected Individual ◽  
Callus Cultures ◽  
Fungal Culture ◽  
Culture Collections ◽  
Flowering Dogwood ◽  
Plant Parasite ◽  
In Vitro Establishment

Microshoot and callus cultures of Cornus florida (flowering dogwood), which were grown on woody plant medium amended with BA, were inoculated with Microsphaera pulchra (an obligate plant parasite) by gently shaking infected leaves bearing numerous conidia over the tissue. Culture dishes were sealed with parafilm and incubated at 24 °C with 25 mol·m–2·s–1 provided by cool fluorescent bulbs for 15 h. Cultures were examined with a dissecting scope every 24 h and cultures transferred when contaminating fungi were present. Specimens were prepared light microscopy and SEM. The fungus infected individual callus cells, but did not sporulate. In contrast, powdery mildew was well-established (both primary and secondary hyphae) in 70% of the microshoot cultures after 6 days and sporulated on 20% by 7 to 8 days. The cellular relationship between host and pathogen in vitro was similar to that found in greenhouse-grown plants. This technique has possible applications in maintaining fungal culture collections and studying host–pathogen relationships under more stringently controlled conditions.

Influence of sowing dates on the incidence of powdery mildew of chilli

2017 ◽  
Vol 4 (2) ◽  
Author(s):  
SUDHEENDRA A. ASHTAPUTRE
Keyword(s):  
Powdery Mildew ◽  
Field Experiment ◽  
Disease Severity ◽  
Agricultural Research ◽  
Time Interval ◽  
Research Station ◽  
Inoculum Potential ◽  
Weather Factors ◽  
Agricultural Research Station ◽  
Sowing Dates

A field experiment was conducted during kharif, 2005 at Agricultural Research station, Devihosur, Haveri, Karnataka to assess the progress of powdery mildew at different time interval of sowing dates. Totally 20 different dates of sowings were imposed in the experiment at an interval of 10 days. The crop sown on last week of May to mid of June recorded minimum disease severity compared to rest of the date of sowings. This clearly indicated that crop sown during this period suffers less, which may be due to low inoculum potential, whereas late sown crop suffers more because of the readily available inoculum in the early sown crops. Low disease severity in last week of May to mid of June sowing may be attributed to the non-congenial weather factors for the development of the disease.

scholarly journals Variety resistance of winter barley to powdery mildew in the field in 1976−2005

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 87-96 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Winter Barley ◽  
Mildew Resistance ◽  
Average Resistance ◽  
The Difference ◽  
The Given ◽  
Resistance Of Varieties

The results of evaluation of powdery mildew resistance in winter barley varieties in 285 Czech Official Trials conducted at 20 locations were analysed. Over the period, the number of varieties tested per year increased from four to seven in 1976−1985 to 53−61 in 2002−2005. To assess the resistance of varieties, only trials with sufficient disease severity were used. In 1976−2000, six varieties (1.7% of the varieties tested in the given years) ranked among resistant (average resistance of a variety in a year > 7.5) including NR-468 possessing the gene <i>Mla13</i>, KM-2099 with <i>mlo</i> and Marinka with the genes <i>Mla7</i>, <i>MlaMu2</i>. In 2001−2005, already 33 varieties (16.9%) ranked among resistant, of which Traminer possessing the genes <i>Ml(St)</i> and <i>Ml(IM9 </i> dominated. The proportion of susceptible varieties (average resistance ≤ 5.5) did not change in the two mentioned periods. Two-rowed varieties began to be tested as late as in 1990 (the first variety was Danilo), however, no difference was found in the resistance of two- and six-rowed varieties. Using an example of two pairs of varieties (Dura-Miraj and Marinka-Tiffany) with identical genes for specific resistance but with different resistance in the field, the efficiency of non-specific resistance is discussed. The resistance of domestic and foreign varieties was similar in 1994−2000; however, in 2001−2005 the difference was 0.75 point to disadvantage of domestic ones.

scholarly journals Continuous Lighting Reduces Conidial Production and Germinability in the Rose Powdery Mildew Pathosystem

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 339-344 ◽  
Author(s):  
A. Suthaparan ◽  
Arne Stensvand ◽  
S. Torre ◽  
Maria L. Herrero ◽  
R. I. Pettersen ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Interspecific Hybrid ◽  
Day Length ◽  
Artificial Light ◽  
Potted Plants ◽  
Severity Of Disease ◽  
Detached Leaves ◽  
Growth Chambers ◽  
The Rose

The effect of day length on production and germinability of conidia and severity of disease caused by Podosphaera pannosa, the causal agent of rose powdery mildew, was studied. Whole potted plants or detached leaves of Rosa interspecific hybrid ‘Mistral’ were inoculated with P. pannosa and exposed to 0, 12, 18, 20, 22, or 24 h of artificial light per day in growth chambers equipped with mercury lamps. Increasing duration of illumination from 18 to 20 to 24 h per day reduced production of conidia by 22 to 62%. Exposure to 24 h of illumination per day also strongly reduced disease severity compared with 18 h. Our results suggest that increasing day lengths from 18 h per day to 20 to 24 h may suppress the disease significantly and, thereby, reduce the need for fungicide applications against powdery mildew.

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

2006 ◽  
Vol 1 (2) ◽  
pp. 275-288 ◽  
Author(s):  
Simone Graeff ◽  
Johanna Link ◽  
Wilhelm Claupein
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Near Infrared ◽  
Plant Stress ◽  
Stress Factors ◽  
Gaeumannomyces Graminis ◽  
Disease Assessment ◽  
Leaf Reflectance ◽  
Reflectance Measurements ◽  
Take All

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.

scholarly journals Nitrogen and Flowering Dogwood. I. Impact of Nitrogen Fertilization Rate on the Occurrence of Spot Anthracnose, Powdery Mildew, and Cercospora Leaf Spot and Their Effect on Tree Growth

2008 ◽  
Vol 26 (4) ◽  
pp. 197-203
Author(s):  
A.K. Hagan ◽  
J.R. Akridge ◽  
K.L. Bowen
Keyword(s):  
Powdery Mildew ◽  
Nitrogen Fertilization ◽  
Leaf Spot ◽  
Tree Height ◽  
Fertilization Rate ◽  
Spot Intensity ◽  
Cercospora Leaf Spot ◽  
Trunk Diameter ◽  
Flowering Dogwood ◽  
N Rates

Abstract Impact of nitrogen (N) rate on spot anthracnose, powdery mildew, and Cercospora leaf spot as well as their impact on the growth of field-grown ‘Cloud 9’ and ‘Cherokee Chief’ flowering dogwood was assessed in 2003, 2004, and 2005. From 2001 to 2005, ammonium nitrate was applied at 4.1, 8.3, 16.5, 33.0 and 66.0 g N·m−2 (37.5, 75, 150, 300, 600 lb N·A−1). Heritage 50W fungicide was applied to one ‘Cherokee Chief’ and ‘Cloud 9’ flowering dogwood in each plot, while the second was untreated. Powdery mildew and Cercospora leaf spot were impacted by N rate more than spot anthracnose. In two of three years, powdery mildew intensified, particularly on the non-treated trees, as N rates increased. Cercospora leaf spot intensity (AUDPCI) and defoliation (AUDPCD) on the fungicide-treated and non-treated trees was influenced by N-rate in two of three and one of three years, respectively. Regardless of fungicide treatment, Cercospora leaf spot incited leaf spotting and defoliation was often lower at the two highest than the two lowest N rates. A reduction in the bract and leaf spot phases of spot anthracnose at the highest N rate was noted in 2004. While spot anthracnose was negatively correlated with trunk diameter in all three years and tree height in 2003 and 2004, Cercospora leaf spot intensity and defoliation were negatively correlated with tree height and trunk diameter in all three and two of three years, respectively. Powdery mildew had no impact on tree height or trunk diameter. Heritage 50W not only controlled spot anthracnose and powdery mildew but also slowed Cercospora leaf spot development sufficiently to enhance leaf retention and fall color.

scholarly journals Detecting Wheat Powdery Mildew and Predicting Grain Yield Using Unmanned Aerial Photography

Plant Disease ◽  
2018 ◽  
Vol 102 (10) ◽  
pp. 1981-1988 ◽  
Author(s):  
Wei Liu ◽  
Xueren Cao ◽  
Jieru Fan ◽  
Zhenhua Wang ◽  
Zhengyuan Yan ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Grain Yield ◽  
Disease Severity ◽  
Flight Altitude ◽  
Imaging Data ◽  
Remote Imaging ◽  
Wheat Powdery Mildew ◽  
Imaging Tool ◽  
Random Coefficient Regression ◽  
Relationship Of

High-resolution aerial imaging with an unmanned aerial vehicle (UAV) was used to quantify wheat powdery mildew and estimate grain yield. Aerial digital images were acquired at Feekes growth stage (GS) 10.5.4 from flight altitudes of 200, 300, and 400 m during the 2009–10 and 2010–11 seasons; and 50, 100, 200, and 300 m during the 2011–12, 2012–13, and 2013–14 seasons. The image parameter lgR was consistently correlated positively with wheat powdery mildew severity and negatively with wheat grain yield for all combinations of flight altitude and year. Fitting the data with random coefficient regression models showed that the exact relationship of lgR with disease severity and grain yield varied considerably from year to year and to a lesser extent with flight altitude within the same year. The present results raise an important question about the consistency of using remote imaging information to estimate disease severity and grain yield. Further research is needed to understand the nature of interyear variability in the relationship of remote imaging data with disease or grain yield. Only then can we determine how the remote imaging tool can be used in commercial agriculture.

scholarly journals Novel Source of Biotic Stress Resistance Identified from Brassica Species and its Wild Relatives

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 195
Author(s):  
Rashmi Yadav ◽  
J. Nanjundan ◽  
Ashish K. Gupta ◽  
Mahesh Rao ◽  
Jameel Akhtar ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Insect Pests ◽  
Indian Mustard ◽  
Wild Relatives ◽  
Lepidium Sativum ◽  
Sclerotinia Stem Rot ◽  
Sources Of Resistance ◽  
Alternaria Blight ◽  
White Rust

In rapeseed and mustard, the major diseases (downy mildew, white rust, Alternaria blight and Sclerotinia stem rot) cause 37–47%loss in pod formation and 17–54% reduction in grain yield. The identification of new sources of resistance is a high priority in breeding programs. About 3000 germplasm accessions of Indian mustard were evaluated under multiple environments (3 seasons) at hot spots (4 locations) and under artificial epiphytophic conditions against insect pests and diseases (aphids, white rust, powdery mildew and Alternaria blight). Accessions IC265495, IC313380, EC766091, EC766133, EC766134, EC766192, EC766230, EC766272 were identified as highly resistant to white rust (A. candida) with disease severity reaction (Percent disease severity Index, PDI = 0) under artificial inoculation. Accession RDV 29 showed the inheritance of resistant source for powdery mildew in Indian mustard. Screening of brassica wild relatives (about 25 species) for white rust found that Brassica fruticulosa, Brassica tournefortii, Camelina sativa, Diplotaxis assurgens, D. catholica, D. cretacia, D. Erucoides, D. Muralis, Lepidium sativum had highly resistance (PDI = 0) to Delhi isolates of white rust. Several traits identified from cultivated and related species will be useful for genetic improvement of rapeseed and mustard.

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