scholarly journals Effects of Microelements on Downy Mildew (Peronospora belbahrii) of Sweet Basil

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1793
Author(s):  
Yigal Elad ◽  
Ziv Nisan ◽  
Ziv Kleinman ◽  
Dalia Rav-David ◽  
Uri Yermiyahu
Keyword(s):  
Field Experiment ◽  
Downy Mildew ◽  
Plant Pathogen ◽  
Host Resistance ◽  
Mode Of Action ◽  
Sweet Basil ◽  
Potted Plants ◽  
Mixture Treatment ◽  
Disease Reduction ◽  
Irrigation Solution

We recently demonstrated that spraying or irrigating with Ca, Mg and K reduces the severity of sweet basil downy mildew (SBDM). Here, the effects of Mn, Zn, Cu and Fe on SBDM were tested in potted plants. The effects of Mn and Zn were also tested under semi-commercial and commercial-like field conditions. Spray applications of a mixture of EDTA-chelated microelements (i.e., Fe-EDTA, Mn-EDTA, Zn-EDTA, Cu-EDTA and Mo) reduces SBDM severity. The application of EDTA chelates of individual microelements (i.e., Fe-EDTA, Mn-EDTA and Zn-EDTA) significantly reduces SBDM in potted plants. Foliar applications of Mn-EDTA and Zn-EDTA are found to be effective under semi-commercial conditions and were, thus, further tested under commercial-like conditions. Under commercial-like conditions, foliar-applied Mn-EDTA and Zn-EDTA decreased SBDM severity by 46–71%. When applied through the irrigation solution, those two microelements reduce SBDM by more than 50%. Combining Mg with Mn-EDTA and Zn-EDTA in the irrigation solution does not provide any additional disease reduction. In the commercial-like field experiment, the microelement-mixture treatment, applied as a spray or via the irrigation solution, was combined with fungicides spray treatments. This combination provides synergistic disease control. The mode of action in this plant–pathogen system may involve features of altered host resistance.

scholarly journals The First Report of Downy Mildew Caused by Peronospora belbahrii on Sweet Basil in Greenhouses in the Czech Republic

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1579-1579 ◽  
Author(s):  
I. Šafránková ◽  
L. Holková
Keyword(s):  
Czech Republic ◽  
Downy Mildew ◽  
Width Ratio ◽  
Specific Sequence ◽  
The Czech Republic ◽  
First Report ◽  
Sweet Basil ◽  
Potted Plants ◽  
Length Width ◽  
Necrotic Spots

Sweet basil (Ocimum basilicum L.) is an aromatic plant that is cultivated as a pot plant in greenhouses or in fields in the Czech Republic. The plants are intended for direct consumption or for drying. In April of 2012, the first large chlorotic from the middle necrotic spots occurred gradually on leaves of pot plants O. basilicum cv. Genovese in greenhouses in Central Bohemia. The characteristic gray to brown furry growth of downy mildew appeared on abaxial surfaces of leaves in the place of chlorotic spots within 3 to 4 days. The infested leaves fell off in the late stages of pathogenesis. The infestation gradually manifested itself in ever-younger plants and in July, cotyledons and possibly the first true leaves were already heavily infected and damaged and these plants rapidly died. The plant damage reached 80 to 100%, so it was necessary to stop growing the plants in the greenhouse at the end of July. The causal agent was isolated and identified as Peronospora belbahrii Thines by means of morphological and molecular characters (2,3). Conidiophores were hyaline, straight, monopodial, 280 to 460 μm, branched three to five times, ended with two slightly curved branchlets with a single conidia on each branchled tip. The longer branchlets measured 13 to 24 μm (average 18.2 μm), the shorter one 4 to 15 μm (average 9.7 μm). Conidia were rounded or slightly ovoid, from brownish to dark brownish, measured 22 to 31 × 20 to 28 μm (length/width ratio 1.2). A pathogen-specific sequence was detected with the help of the pathogen ITS rDNA specific primers in symptomatic leaves (1). DNA from plant tissues was isolated using the DNeasy plant Mini Kit (Qiagen, Germany) following the standard protocol. PCR was performed using KAPA2G Robust HotStar kit (Kapa Biosystems, United States) according to the conditions recommended in Belbahri et al. (1). The specific products were visualized by electrophoresis through 1.5% agarose gels. Leaves of 20-day-old potted plants O. basilicum ‘Genovese’ were inoculated by spraying with 5 × 105 conidia/ml of the pathogen. Each pot contained 10 plants. Sterilized distilled water was applied to control plants. Plants were covered with polyethylene bags during the entire incubation period to maintain high humidity, and kept at a temperature of 22 to 24°C. Typical disease symptoms appeared on leaves 5 to 9 days after inoculation. Control plants were symptomless. P. belbahrii was re-isolated from the lesions of inoculated plants, thus fulfilling Koch's postulates. Downy mildew on sweet basil was reported in countries in Africa, Europe, and South and North America (4). To our knowledge, this is the first report of downy mildew on sweet basil in the Czech Republic. References: (1) L. Belbahri et al. Mycol. Res. 109:1276, 2005. (2) Y.-J. Choi et al. Mycol. Res. 113:1340, 2009. (3) M. Thines et al. Mycol. Res. 113:532, 2009. (4) C. A. Wyenandt et al. HortScience 45:1416, 2010.

scholarly journals Draft Genome Sequence of Plasmopara viticola , the Grapevine Downy Mildew Pathogen

2016 ◽  
Vol 4 (5) ◽  
Author(s):  
Yann Dussert ◽  
Jérôme Gouzy ◽  
Sylvie Richart-Cervera ◽  
Isabelle D. Mazet ◽  
Laurent Delière ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Genome Sequence ◽  
Genome Analysis ◽  
Plant Pathogen ◽  
Host Resistance ◽  
Draft Genome ◽  
Plasmopara Viticola ◽  
Host Specialization ◽  
Grapevine Downy Mildew ◽  
Plant Pathogen Interactions

Plasmopara viticola is a biotrophic pathogenic oomycete responsible for grapevine downy mildew. We present here the first draft of the P. viticola genome. Analysis of this sequence will help in understanding plant-pathogen interactions in oomycetes, especially pathogen host specialization and adaptation to host resistance.

scholarly journals Effects of Calcium, Magnesium and Potassium on Sweet Basil Downy Mildew (Peronospora belbahrii)

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 688
Author(s):  
Yigal Elad ◽  
Ziv Kleinman ◽  
Ziv Nisan ◽  
Dalia Rav-David ◽  
Uri Yermiyahu
Keyword(s):  
Downy Mildew ◽  
Ocimum Basilicum ◽  
Disease Suppression ◽  
Fungicide Treatment ◽  
Sweet Basil ◽  
Potted Plants ◽  
Growing Seasons ◽  
Calcium Magnesium ◽  
K Concentration ◽  
Better Than

Downy mildew (Peronospora belbahrii) is a major disease of sweet basil (Ocimum basilicum). We examined the effects of potassium, calcium and magnesium, individually and in combination, on sweet basil downy mildew (SBDM) in potted plants and under commercial-greenhouse conditions over six growing seasons. An increased K concentration in the fertigation solution increased SBDM severity, whereas foliar-applied KCl and K2SO4 suppressed SBDM. The application of higher concentrations of those salts increased the K concentrations in the shoots and significantly alleviated SBDM. Increased concentrations of Ca or Mg in the fertigation solution decreased SBDM severity, as did foliar-applied CaCl2. However, the combination of Ca and Mg did not have any synergistic effect. Foliar-applied K2SO4 provided better disease suppression than some of these treatments. The 3.3 mM Mg + fungicide treatment and the 5.0 mM Mg + fungicide treatment each provided synergistic disease control in one of two experiments. SBDM severity was significantly reduced by MgCl2 and MgSO4 (both 3.3 mM Mg), as compared with the basic Mg fertigation (1.6 mM), with MgCl2 providing better control. The combined Mg salts + fungicide treatments reduced SBDM better than any of those treatments alone. These results demonstrate that macro-elements can contribute to SBDM control.

scholarly journals Adaptation of a plant pathogen to partial host resistance: selection for greater aggressiveness in grapevine downy mildew

2016 ◽  
Vol 9 (5) ◽  
pp. 709-725 ◽  
Author(s):  
Chloé E. L. Delmas ◽  
Frédéric Fabre ◽  
Jérôme Jolivet ◽  
Isabelle D. Mazet ◽  
Sylvie Richart Cervera ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Plant Pathogen ◽  
Host Resistance ◽  
Grapevine Downy Mildew ◽  
Resistance Selection ◽  
Selection For

scholarly journals Integrated Management of Downy Mildew on Slicing Cucumber With Fungicides and Host Resistance But Not Trellising

Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2592-2598
Author(s):  
Anthony P. Keinath
Keyword(s):  
Downy Mildew ◽  
Host Resistance ◽  
Management Practices ◽  
Integrated Management ◽  
Cultivar Resistance ◽  
Fall Season ◽  
Fungicide Treatment ◽  
Progress Curve ◽  
Management Techniques ◽  
The Mean

The objective of this study was to evaluate fungicide applications, host resistance, and trellising, alone and in combination, as management practices for downy mildew on slicing cucumber. A split-split plot experimental design was used with three and four replications in spring and fall 2017, respectively. The whole-plot treatment was fungicide, four applications of chlorothalonil (Bravo Weather Stik 6SC) alternated with three applications of cyazofamid (Ranman 400SC), or water. Split plots were nontrellised or trellised with four strings supported by stakes. Split-split plots were cultivar Bristol, which is intermediately resistant to downy mildew, or cultivar Speedway, which is susceptible to downy mildew with similar parentage as Bristol. In both seasons, area under the disease progress curve (AUDPC) values were lower with fungicides than water for both cultivars. In the spring, AUDPC for Bristol was lower than for Speedway regardless of fungicide treatment. In the fall, Bristol had a lower AUDPC than Speedway with fungicides, but the AUDPC did not differ between the two cultivars with water. The mean AUDPC for trellised plants (376.2) was lower than for nontrellised plants (434.0; P = 0.007). Fungicide applications increased marketable and total fruit weights in both seasons (P ≤ 0.0002). Marketable weight with fungicides was almost double (93% greater) the marketable weight with water. Marketable weight was 55% greater for Bristol than for Speedway in spring, but yields did not differ between cultivars in fall (season-by-cultivar interaction, P ≤ 0.0003). Because trellising had no effect on marketable yields (P = 0.11), trellising is not recommended for managing downy mildew on slicing cucumber. Of the three management techniques examined, fungicides had the largest effects on disease and yields, followed by cultivar resistance.

Peronospora sordida. [Descriptions of Fungi and Bacteria].

1991 ◽  
Author(s):  
G. Hall
Keyword(s):  
New York ◽  
North America ◽  
Northern Ireland ◽  
Downy Mildew ◽  
Geographical Distribution ◽  
Plant Pathogen ◽  
Disease Transmission ◽  
Channel Islands ◽  
Rain Splash

Abstract A description is provided for Peronospora sordida. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Scrophularia altaica, S. aquatica, S. auriculata, S. bosniaca, S. californica, S. heterophylla, S. lanceolata, S. marylandica, S. nodosa, S. scopolii, S. umbrosa (=S. alata), Verbascum banaticum, V. blattaria, V. densiflorum (=V. thapsiforme), V. glabratum subsp. glabratum, V. lychnitis, V. nigrum, V. phlomoides, V. phoenicum, V. speciosum, V. thapsus, V. thapsus subsp. crassifolium (=V. montanum), V. virgatum. DISEASE: Downy mildew of Scrophularia and Verbascum, some species of which may be cultivated commercially for their medicinal or ornamental value; an obligately necrotrophic plant pathogen. GEOGRAPHICAL DISTRIBUTION: Asia; USSR (Kirghizia, Turkmenia, Uzbekistan). Europe; Austria, Belgium, France, Czechoslovakia, Denmark, Eire, Finland, Germany, Hungary, Italy, Netherlands, Norway, Poland, Rumania, USSR (Byelorussia, Estonia, Latvia, Lithuania, RSFSR, Ukraine), Sweden, Switzerland, UK (England, Channel Islands, Northern Ireland, Scotland, Wales), Yugoslavia. North America; USA (California, Illinois, Indiana, Iowa, Kansas, Kentucky, Missouri, Nebraska, New York, Ohio, Wisconsin, Virginia). TRANSMISSION: By spores ('conidia') dispersed by wind or rain-splash. The role of oospores (if they are usually formed) in disease transmission is unknown.

scholarly journals The Potential of RIP (Ribosome Inactivating Protein) as Biopesticides

Buletin Eboni ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 33-39
Author(s):  
Tati Suharti ◽  
Dharmawati F Djam’an
Keyword(s):  
Protein Synthesis ◽  
Broad Spectrum ◽  
Plant Pathogen ◽  
Mode Of Action ◽  
Castor Bean ◽  
Insect Pests ◽  
Bitter Melon ◽  
Ribosome Inactivating Protein ◽  
High Potency ◽  
Anti Fungal

RIP (Ribosome Inactivating Protein) produced by plants that can act as a plant defense from pest and disease. This protein is widely used as an anti-fungal, anti-bacterial, anti-virus and anti-insect. Therefore, RIP contained in plants has the potential to be used for environmentally friendly biopesticides. The purpose of this paper is to provide information on RIP derived from plants and its potential as a biopesticide.The mode of action of RIP works is by inhibiting protein synthesis during translating process of pest and plant pathogen. RIP has a broad spectrum so that it can overcome insect pests from various orders and pathogens both fungi, bacteria and viruses. Some types of plants that contain RIP include neem, ginger, turmeric, galangal, castor bean, jatropha, soursop and bitter melon. RP applications can be in the form of oil, essential oils, solutions, flour, ash and simplicia. RIP can be applied to seeds, seeds, plants and post-harvest products. The advantages of using RIP include easily available materials, inexpensive, easy to application and environmentally friendly.The plants contain RP has high potency to commercially developed so in the future, the controlling of pest and disease rely on the plants contain RIP both direct and in the pesticides formulations form. Therefore echo friendly plantation programme can be realized.

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