scholarly journals The Use of Film-Forming Polymers to Control Guignardia Leaf Blotch and Powdery Mildew on Aesculus hippocastanum L. and Quercus robur L.

2006 ◽  
Vol 32 (3) ◽  
pp. 100-107
Author(s):  
Glynn Percival ◽  
Ian Keary ◽  
Kelly Marshall
Keyword(s):  
Chlorophyll Fluorescence ◽  
Powdery Mildew ◽  
Disease Severity ◽  
Quercus Robur ◽  
Aesculus Hippocastanum ◽  
Leaf Blotch ◽  
Tree Vitality ◽  
Plant Disease Control ◽  
Film Forming ◽  
Leaf Chlorophyll Fluorescence

The effects of four commercially available film-forming polymers (Bond, Designer, Spray Gard, Nu-Film-P) on disease severity of powdery mildew (Microsphaera alphitoides Griffon and Maubl.) on English oak (Quercus robur L.) and Guignardia leaf blotch (Guignardia aesculi (Peck) Stewart) on horsechestnut (Aesculus hippocastanum L.) were examined in a field experiment. In addition, a comparative evaluation of the fungicide penconazole, commercially used for powdery mildew control, was conducted. Effects on tree vitality were also assessed by measuring leaf chlorophyll fluorescence and chlorophyll concentrations. Irrespective of tree species, Nu-Film-P and Spray Gard did not significantly influence disease severity of powdery mildew and Guignardia leaf blotch. Likewise, no significant effects of these two film-forming polymers on chlorophyll fluorescence and chlorophyll content were recorded. Reduction in disease severity following spray applications of the film-forming polymers Bond and Designer was statistically comparable with penconazole. None of the film-forming polymers and fungicide evaluated was phytotoxic to the test trees. Results suggest that application of an appropriate film-forming polymer may provide a useful addition to existing methods of plant disease control.

scholarly journals Fungicides against diseases of lawn grass leaves

2019 ◽  
pp. 7-9
Author(s):  
S. Retman ◽  
O. Nychyporuk ◽  
О. Shevchuk
Keyword(s):  
Powdery Mildew ◽  
Technical Efficiency ◽  
Disease Severity ◽  
Growing Season ◽  
Disease Spread ◽  
Septoria Leaf Blotch ◽  
Leaf Blotch ◽  
Chemical Groups ◽  
Positive Effect

Goal. To evaluate the effectiveness of the use of fungicides of various chemical groups against the leaf diseases turfgrass. Methods. The research was carried out in 2015—2017 on the lawn mixture «Universal» in the zone of the Polissya of Ukraine. The effect of fungicides of various chemical groups was investigated (Impact T, SC; Bumper Super, EC; Amistar Extra 280 SC, SC; Alto Super 300 EC, EC; Maxim 025 FS, FS; Horus 75 WG, WG). Fungicides were applied twice. The first spraying was carried out when development of diseases in control plot reached 3—5%, the second — in 30 days. The assessments were performed according to generally accepted methods, disease spread, disease severity and technical efficiency of pesticides were determined. Results. During the period of research, the most common leaf diseases of turfgrass, which eveloped annually and had a significant severity during the growing season, were powdery mildew and septoria leaf blotch. After two-time spraying, the technical efficiency of fungicides against powdery mildew reached 82.2—92.2%, against septoria leaf blotch up to 80.2%. The most effective against powdery mildew was the use of Alto Super 330 EC, EC (0.5 l / ha), Amistar Extra 280 SC, SC (0.75 l / ha) and tank mixture of Maxim 025 FS, FS (0.75 l / ha and 1.0 l / ha) with Horus 75 WG, VH (0.6 kg / ha). Against the septoria leaf blotch, the highest efficiency was shown by Alto Super 330 EC, EC (0.5 l / ha), Bumper Super, EC (0.8 l / ha) and Maxim 025 FS, FS (1.0 l / ha) + Horus 75 WG, WG (0.6 kg / ha). In addition, due to the reduction of disease severity, a positive effect of fungicides on the quality of the lawn was achieved and the projective coating increased to 92—93%. Conclusion. The use of fungicides contributes to the reduction of disease and the formation of quality herbs. The best indicators against flour dew and septoriosis of leaves were obtained for the treatment of Alto Super 330 EC, CE (0.5 l / ha) and tank Maxim 025 FS, tc.s. (1.0 l / ha) + Horus 75 WG, VH (0.6 kg / ha).

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 Long-term field fertilization experiment with energy willow (Salix sp.) − Elemental composition and chlorophyll fluorescence in the leaves

2018 ◽  
Vol 67 (1) ◽  
pp. 91-103
Author(s):  
László Simon ◽  
Marianna Makádi ◽  
György Vincze ◽  
Zsuzsanna Uri ◽  
Katalin Irinyiné Oláh ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Crop ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Fertilization Experiment ◽  
Nitrogen Concentrations ◽  
Set Up ◽  
Leaf Chlorophyll Fluorescence ◽  
Term Field

A small-plot long-term field fertilization experiment was set up in 2011 with willow (Salix triandra x Salix viminalis ’Inger’) grown as an energy crop in Nyíregyháza, Hungary. The brown forest soil was treated three times (in June 2011, May 2013, May 2016) with municipal biocompost (MBC), municipal sewage sludge compost (MSSC) or willow ash (WA), and twice (June 2011, May 2013) with rhyolite tuff (RT). In late May – early June 2016 urea (U) and sulphuric urea (SU) fertilizers were also applied to the soil as top-dressing (TD). These fertilizers and amendments were also applied to the soil in 2016 in the combinations; MBC+SU, RT+SU, WA+SU and MSSC+WA. All the treatments were repeated four times. In July 2016 the highest nitrogen concentrations in willow leaves were measured in the U (3.47 m/m%) and SU (3.01 m/m%) treatments, and these values were significantly higher than the control (2.46 m/m%). An excess of nitrogen considerably reduced the Zn uptake of the leaves, with values of 39.5 μg g-1 in the U treatment, 53.4 μg g-1 in the SU treatment, and 63.5 μg g-1 in the control. All other amendments or TDs, except for WA, enhanced the specific potassium concentrations in willow leaves compared to the control. No significant quantities of toxic elements (As, Ba, Cd, Pb) were transported from soil amendments or TDs to the willow leaves. In July 2016 the most intensive leaf chlorophyll fluorescence was observed in the MSSC and MSSC+WA treatments.

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.

Leaf chlorophyll fluorescence discriminates herbicide resistance inEchinochloaspecies

Weed Research ◽  
2016 ◽  
Vol 56 (6) ◽  
pp. 424-433 ◽  
Author(s):  
C J Zhang ◽  
S H Lim ◽  
J W Kim ◽  
G Nah ◽  
A Fischer ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Herbicide Resistance ◽  
Leaf Chlorophyll ◽  
Leaf Chlorophyll Fluorescence

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 Paclobutrazol Soil Drenches Provide Partial Reductions in Symptoms of Apple Scab of Ornamental Trees and Guignardia Leaf Blotch of Horse Chestnut

2008 ◽  
Vol 26 (2) ◽  
pp. 87-92
Author(s):  
G.C. Percival
Keyword(s):  
Fungal Pathogens ◽  
Growth Regulation ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Control Policy ◽  
Leaf Size ◽  
Horse Chestnut ◽  
Leaf Blotch ◽  
Pathogen Control ◽  
Leaf Chlorophyll Fluorescence

Abstract A three year field trial was conducted using established apple (Malus cv. Crown Gold) and horse chestnut (Aesculus hippocastanum L.) to assess the efficacy of paclobutrazol (PBZ) root drenches against the foliar pathogens apple scab (Venturia inaequalis (Cooke) G. Wint.,) and Guignardia leaf blotch (Guignardia aesculi (Peck) VB Stewart). In the case of horse chestnut, pathogen severity of Guignardia leaf blotch was less (23–79%) in each of the three-year experimental periods in PBZ-treated trees compared to non-treated controls. Pathogen severity of apple scab was not affected during the first year after PBZ application; however, less (25–73%) disease severity was recorded in years 2 and 3 compared to non-PBZ treated controls. An increased PBZ concentration was associated with lower pathogen severity of both fungal pathogens. Irrespective of species, less pathogen severity in PBZ-treated trees was accompanied with greater leaf chlorophyll fluorescence (16–49%) values as measures of leaf photosynthetic efficiency. Marked differences in growth regulation between apple cv. Crown Gold (tolerant) and horse chestnut (sensitive) were recorded. PBZ applications resulted in less mean stem extension in both tree species but only reduced mean leaf size of horse chestnut. Based on the results of this investigation it is suggested that PBZ root drenches potentially offer a means of reducing the severity of apple scab and Guignardia leaf blotch for professionals involved with the nursery industry. However, where a zero pathogen control policy is required supplementary fungicide sprays would be needed. Similarly, the potential loss of aesthetics due to excessive growth regulation needs to be weighed against the benefits of pathogen protection and failure of PBZ to achieve total pathogen control may result in strong selection pressure for PBZ resistance in surviving populations.

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