scholarly journals Effective Management of Cucumber Powdery Mildew with Essential Oils

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1177
Author(s):  
Yasser S. Mostafa ◽  
Mohamed Hashem ◽  
Ali M. Alshehri ◽  
Saad Alamri ◽  
Ebrahem M. Eid ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Essential Oils ◽  
Disease Incidence ◽  
Its Region ◽  
Dry Weight ◽  
Positive Control ◽  
Powdery Mildew Fungus ◽  
Membrane Injury ◽  
Cucumber Powdery Mildew

This research evaluated the efficacy of essential oils in the management of cucumber powdery mildew. Essential oils of lemongrass, lemon, thyme, peppermint, abundance blend, purification blend, and thieves blend were tested in vitro and under greenhouse conditions in two separate experiments. The effects of essential oils were tested against powdery mildew disease at concentrations of 1.0–2.5 mL/L, and the consequent impact of the oils on plant growth was evaluated. Powdery mildew fungus, Podosphaera xanthii, was identified using sequencing of the ITS region. The essential oils significantly reduced disease incidence up to 77.3% compared with the positive control (p < 0.5). Moreover, the essential oils increased the plant length (up to 187 cm), leaf area (up to 27.5 cm2), fresh weight (up to 123 g), dry weight (up to 22.5 g), number of flowers (16.3), and metabolite content compared with the positive control (p < 0.5). Cell membrane injury decreased significantly in the oil-treated pants (p < 0.5), indicating the protective effect of essential oils. This study recommends the application of essential oils in an appropriate dose (2.5 mL/L) to protect cucumber plants against powdery mildew. Overdose of the oils (more than 2.5 mL/L) should be avoided due to adverse effects.

scholarly journals Bicarbonates and Botrytis: VI. Control of Gray Mold Enhances Geranium Growth

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 767A-767
Author(s):  
C.L. Palmer ◽  
R.W. Langhans ◽  
R.K. Horst ◽  
H.W. Israel
Keyword(s):  
Powdery Mildew ◽  
Plant Height ◽  
Disease Incidence ◽  
Dry Weight ◽  
Colony Growth ◽  
Gray Mold ◽  
Disease Development ◽  
Development Data ◽  
Low Levels

Botrytis cinerea Pers. causes gray mold on greenhouse-grown geraniums (Pelargonium ×hortorum L. H. Bailey), among many other crops. Bicarbonates effectively control rose powdery mildew (Plant Dis. 76:247–480) and inhibit B. cinerea in vitro colony growth and conidial germination (Phytopathology 84:546, 1065). To examine bicarbonate effects on gray mold incidence and geranium growth, we sprayed seedling geranium cultivars Red Elite and Scarlet Elite weekly with 0, 25, and 50 mM NH4HCO3 or KHCO3. Seedlings were transplanted in Metromix 360 and misted every 24 m for 5 s to enhance disease development. Data were collected biweekly on disease incidence, floral number, plant height, and dry weight. Both cultivars performed similarly. Disease incidence decreased with application of bicarbonates. KHCO3 at 25 mM slightly increased dry weight and height over 0 mM, whereas 25 and 50 mM NH4HCO3 greatly increased both features. Fifty mM KHCO3 decreased height slightly, but had no effect on dry weight. Floral number decreased slightly with all bicarbonate treatments. It is indicated that KHCO3 at low levels and NH4HCO3 enhance seedling geranium growth by controlling gray mold incidence and by providing additional nutrients. (Supported by H&I Agritech Inc., Ithaca, NY 14850.)

scholarly journals In Vitro Evaluation of Acute Toxicity of Five Citrus spp. Essential Oils towards the Parasitic Mite Varroa destructor

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1182
Author(s):  
Roberto Bava ◽  
Fabio Castagna ◽  
Cristian Piras ◽  
Ernesto Palma ◽  
Giuseppe Cringoli ◽  
...  
Keyword(s):  
Essential Oils ◽  
Honey Bee ◽  
Varroa Destructor ◽  
Negative Impact ◽  
Positive Control ◽  
Citrus Limon ◽  
Citrus Paradisi ◽  
Bee Health ◽  
Citrus Spp

Varroa destructor is the most important ectoparasitic mite of honey bees that has a negative impact on bee health and honey production. The control programs are mainly based on the use of synthetic acaricides that are often administered indiscriminately. All this has led to drug resistance that now represent a great concern for honey bee farming. The research for alternative products/methods for mites’ control is now mandatory. The aim of this study was to test whether Citrus spp. essential oils could diminish the growth of the V. destructor mite. In Calabria (southern Italy), plants of the Citrus genus are very common and grow both spontaneously and cultured. The essential oils used in this study were extracted from bergamot (Citrus bergamia), grapefruit (Citrus paradisi), lemon (Citrus limon), orange (Citrus sinensis), and mandarin (Citrus reticulata) by hydrodistillation. Every EO was in vitro tested against V. destructor. Each experimental replicate was performed using 35 viable adult female mites (5 for each EO) collected the same day from the same apiary and included negative controls (5 individuals exposed to acetone only) and positive controls (5 individuals exposed to Amitraz diluted in acetone). The essential oils (Eos) were diluted (0.5 mg/mL, 1 mg/mL, and 2 mg/mL) in HPLC grade acetone to obtain the working solution to be tested (50 µL/tube). Mite mortality was manually assessed after 1 h exposure under controlled conditions. The essential oils that showed the best effectiveness at 0.5 mg/mL were bergamot, which neutralized (dead + inactivated) 80% (p ≤ 0.001) of the parasites; grapefruit, which neutralized 70% (p ≤ 0.001); and lemon, which neutralized 69% of them. Interestingly, the positive control (Amitraz) at the same concentration neutralized 60% of the parasites. These results demonstrate that Calabrian bergamot, grapefruit, and lemon Eos consistently reduced V. destructor viability and open the possibility for their utilization to control this parasite in honey bee farming.

scholarly journals Inhibitory Effect of Trichoderma asperellum Isolate against Ralstonia solanacearum Causing Brinjal Wilt

2021 ◽  
Vol 24 (2) ◽  
pp. 107-120
Author(s):  
SMN Islam ◽  
SS Siddique ◽  
MZH Chowdhury ◽  
NJ Mishu
Keyword(s):  
Ralstonia Solanacearum ◽  
Disease Incidence ◽  
Its Region ◽  
Inhibitory Effect ◽  
Dual Culture ◽  
Trichoderma Asperellum ◽  
In Planta ◽  
Quantitative Test ◽  
Trichoderma Isolate

A native Trichoderma isolate was collected from the agricultural soil of Gazipur. This isolate was identified as a Trichoderma asperellum through morphology and analysis of internal transcribed spacer (ITS) region of ribosomal RNA gene sequence and reconstruction of the phylogenetic tree. The antagonistic effects of the newly identified T. asperellum isolate were assessed against brinjal bacterial wilt caused by Ralstonia solanacearum both in vitro and in planta. Both qualitative and quantitative bioassays were conducted in vitro. For qualitative tests, dual culture and antibacterial activity were carried out, and pathogen growth was observed visually. The antagonism of T. asperellum cell free culture filtrate on the growth of R. solanacearum was conducted in a quantitative test. Successful antagonism was recorded after both in vitro qualitative tests. In addition, the lowest colony forming unit was recorded in 100% of CFC (2.4±0.51 ×103 cfu/ml) in quantitative test. The T. asperellum inoculated plant showed low disease incidence (13.33%) when seedlings were challenged with R. solanacearum in planta experiment. Disease incidence was 100% for seedlings when treated with only R. solanacearum. The results showed that the isolated and identified T. asperellum isolate suppressed R. solanacearum growth in vitro and protected the seedling from wilting in planta. Therefore, this isolate could be considered as a potential isolate. Ann. Bangladesh Agric. (2020) 24(2) : 107-120

scholarly journals Potential Application of Prunus armeniaca L. and P. domestica L. Leaf Essential Oils as Antioxidant and of Cholinesterases Inhibitors

Antioxidants ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 2 ◽  
Author(s):  
Marco Bonesi ◽  
Maria Tenuta ◽  
Monica Loizzo ◽  
Vincenzo Sicari ◽  
Rosa Tundis
Keyword(s):  
Gas Chromatography ◽  
Essential Oils ◽  
Antioxidant Properties ◽  
Positive Control ◽  
Prunus Armeniaca ◽  
Gas Chromatography Mass Spectrometry ◽  
Flame Ionization ◽  
Ic50 Values ◽  
Comprehensive Comparison

The aim of this work is to investigate the in vitro acetylcholinesterase (AChE) and butyrycholinesterase (BChE) inhibitory activities of essential oils obtained by hydrodistillation from the leaves of Prunus armeniaca and P. domestica in relation to their composition, analysed by Gas Chromatography–Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS) analyses, at different times. Moreover, considering the role of free radicals in the progression of neurodegenerative disorders, the antioxidant properties of essential oils were investigated by using, 2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and β-carotene bleaching tests. The relative antioxidant capacity index (RACI) was used to achieve more comprehensive comparison between analysed antioxidant effects of essential oils. P. armeniaca oils were more active than P. domestica oils against AChE. Against BChE, the most active was the essential oil from P. domestica leaves collected in August with an IC50 value of 95.80 μg/mL. This oil exerted the highest inhibitory activity of lipid peroxidation with IC50 values of 11.15 and 11.39 μg/mL after 30 and 60 min of incubation, respectively. All samples demonstrated a remarkable ABTS radicals scavenging activity, with IC50 values in the range 0.45–0.57 μg/mL in comparison to the positive control, ascorbic acid.

scholarly journals First Report of Powdery Mildew Caused by Podosphaera xanthii on Cucurbita argyrosperma in Mexico

Plant Disease ◽  
2021 ◽  
Author(s):  
José Francisco Díaz-Nájera ◽  
Sergio Ayvar-Serna ◽  
Antonio Mena-Bahena ◽  
Guadalupe Arlene Mora-Romero ◽  
Karla Yeriana Leyva-Madrigal ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Microscopic Examination ◽  
Disease Incidence ◽  
Phylogenetic Analyses ◽  
Its Region ◽  
Likelihood Method ◽  
28S Rrna ◽  
Podosphaera Xanthii ◽  
Voucher Specimen ◽  
First Report

Cucurbita argyrosperma, commonly named as winter or cushaw squash, is highly sought for its seeds, which have important uses in culinary arts. During the autumn 2021, powdery mildew-like signs and symptoms were observed on cushaw squash in several commercial fields located in Cocula, Guerrero, Mexico. Signs were initially appeared as whitish powdery patches on both sides of leaves and then covering entire leaves and causing premature senescence. The disease incidence was estimated to be 80% in about 1000 plants in two fields. The mycelium was amphigenous, persistent, white in color, and occurred in dense patches. A voucher specimen was deposited in the Herbarium of the Colegio Superior Agropecuario del Estado de Guerrero under the accession number CSAEG22. For the morphological characterization by light microscopy, fungal structures were mounted in a drop of lactic acid on a glass slide. Microscopic examination showed nipple-shaped hyphal appressoria. Conidiophores (n = 30) were straight, 100 to 190 × 10 to 12 μm and produced 2 to 6 conidia in chains. Foot-cells were cylindrical, 41 to 78 μm long, followed by 1 to 2 shorter cells. Conidia (n = 100) were ellipsoid-ovoid to barrel-shaped, 29.5 to 39.1 × 19.4 to 22.7 μm, and contained conspicuous fibrosin bodies. Germ tubes were produced from a lateral position on conidia. Chasmothecia were not observed during the growing season. The morphological characters were consistent with those of the anamorphic state of Podosphaera xanthii (Braun and Cook 2012). For further confirmation, total DNA was extracted from conidia and mycelia following the CTAB method (Doyle and Doyle 1990), and the internal transcribed spacer (ITS) region and part of the 28S gene were amplified by PCR, and sequenced. The ITS region of rDNA was amplified using the primers ITS5/ITS4 (White et al. 1990). For amplification of the 28S rRNA partial gene, a nested PCR was performed using the primer sets PM3 (Takamatsu and Kano 2001)/TW14 (Mori et al. 2000) and NL1/TW14 (Mori et al. 2000) for the first and second reactions, respectively. Phylogenetic analyses using the Maximum Likelihood method, including ITS and 28S sequences of isolates of Podosphaera spp. were performed and confirmed the results obtained in the morphological analysis. The isolate CSAEG22 grouped in a clade with isolates of Podosphaera xanthii. The ITS and 28S sequences were deposited in GenBank under accession numbers OL423329 and OL423343, respectively. Pathogenicity was confirmed by gently dusting conidia from infected leaves onto ten leaves of healthy C. argyrosperma plants. Five non-inoculated leaves served as controls. The plants were maintained in a greenhouse at 25 to 35 ºC, and relative humidity of 60 to 70%. All inoculated leaves developed similar signs to the original observation after 10 days, whereas control leaves remained symptomless. Microscopic examination of the fungus on inoculated leaves showed that it was morphologically identical to that originally observed on diseased plants, fulfilling Koch’s postulates. Podosphaera xanthii has been previously reported on C. maxima, C. moschata, and C. pepo in Mexico (Yañez-Morales et al. 2009; Farr and Rossman 2021). To our knowledge, this is the first report of P. xanthii causing powdery mildew on C. argyrosperma in Mexico. This pathogen is a serious threat to C. argyrosperma production in Mexico and disease management strategies should be developed.

scholarly journals Role of hydrogen peroxide and Pharmaplant-turbo against cucumber powdery mildew fungus under organic and inorganic production

2008 ◽  
Vol 14 (3) ◽  
Author(s):  
Y. M. Hafez ◽  
Y. A. Bayoumi ◽  
Z. Pap ◽  
N. Kappel
Keyword(s):  
Hydrogen Peroxide ◽  
Powdery Mildew ◽  
Disease Severity ◽  
Ascorbic Acid Content ◽  
Plant Diseases ◽  
Organic Fertilizers ◽  
Nitrate Content ◽  
Antifungal Compound ◽  
Powdery Mildew Fungus ◽  
Cucumber Powdery Mildew

Cucumber leaves have been sprayed with a solution of hydrogen peroxide (H202) or Pharmaplant-turbo combined with organic or inorganic fertilizers under plasic house. Under the influence of H202, leaves exhibited resistant against Podoshaera fusca fungus, the causal agent of cucumber powdery mildew. H202 (15 mM) was able to decrease the disease severity from 90.4% to 12% in two experiments conducted in two seasons. Pharmaplant-turbo (Turbo) is new chemical compound and used as an antifungal compound. Turbo in 1 ml/L was able to decrease the disease severity from 90.4% to 11.5% in the both experiments as well. Both of H202 and Turbo were combined with organic treatment (compost + compost tea + seaweed extracts) which showed significant effect against cucumber powdery mildew fungus and strongly suppressed it as compared to control leaves. Organic treatment produced higher vegetative growth characters and greater early and total yields as compared to inorganic treatment, also organic fruits produced the lower nitrate content and the higher ascorbic acid content as compared to inorganic fruits. Our study have indicated that, H202 and Turbo combined with organic fertilizers play a role in the resistance of cucumber against powdery mildew by decreasing the disease severity. We suggest to give more attention to the direct application of H202 in low concentration and Turbo against powdery mildew diseases and other plant diseases.

scholarly journals Powdery Mildew Caused by Golovinomyces orontii on Creeping Bellflower (Campanula rapunculoides) in Italy

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 291-291 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
A. Poli ◽  
M. L. Gullino
Keyword(s):  
Powdery Mildew ◽  
Signs And Symptoms ◽  
Its Region ◽  
Herbaceous Plant ◽  
Pathogenicity Test ◽  
Academic Press ◽  
Powdery Mildew Fungus ◽  
Golovinomyces Orontii ◽  
Conidial Morphology ◽  
Eastern European Countries

Creeping (June) bellflower (Campanula rapunculoides) is an herbaceous plant belonging to the Campunalaceae family. It has showy flowers, which is very much appreciated for gardens and landscaping. During the summer of 2011, 6- to 9-month-old plants grown in a garden near Biella (northern Italy) showed signs and symptoms of an unknown powdery mildew. The adaxial leaf surfaces were covered with white mycelia and conidia, while the abaxial surfaces were less infected. As the disease progressed, infected leaves turned yellow and wilted. Mycelia were also observed on stems, petioles, and flower calyxes of inflorescences. Seventy percent of plants were diseased. Conidia were hyaline, elliptical to ovoid (sometimes doliform), borne in short chains (up to three conidia per chain), and measured 27 to 42 (34) × 16 to 24 (19) μm. Conidiophores were erect with a cylindrical foot cell measuring 64 to 105 (80) × 11 to 12 (11) μm and followed by two shorter cells measuring 17 to 24 (20) × 11 to 15 (13) μm. Fibrosin bodies were absent. Chasmothecia were not observed in the collected samples. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1F/ITS4 and sequenced (3) (GenBank Accession No. JN639855). The 405-bp amplicon had 98% homology with the sequence of Golovinomyces orontii GQ183948. Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of healthy C. rapunculoides plants. Three plants were inoculated while the same number of noninoculated plants served as a control. Plants were maintained outside at temperatures from 10 to 26°C. Fifteen days after inoculation, symptoms and signs of powdery mildew developed on inoculated plants. The conidial morphology of the powdery mildew fungus that developed on inoculated plants was identical to the conidial morphology observed in the original fungus. Noninoculated plants remained healthy. The pathogenicity test was carried out twice. G. orontiii has been reported on C. rapunculoides in several eastern European countries as well as in Switzerland and Germany (1,2). To our knowledge, this is the first report of the disease in Italy. The economic importance of this disease is currently limited in Italy because of limited planting of this host. References: (1) A. Bolay. Cryptogam. Helv. 20:1, 2005. (2) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Stuttgart, Germany, 1995. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

scholarly journals Essential oils in the management of soft rot of kale in the brazilian semiarid region

2020 ◽  
Vol 36 ◽  
Author(s):  
Marcia Ferreira Queiroz ◽  
Meridiana Araujo Gonçalves Lima ◽  
Josineide Edinalva Pereira ◽  
Karol Alves Barroso ◽  
Cristiane Domingos Da Paz ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Essential Oils ◽  
Disease Control ◽  
Disease Incidence ◽  
Soft Rot ◽  
Semiarid Region ◽  
Post Inoculation ◽  
Clove Oil ◽  
Lemongrass Oil

The aim of this study was to analyze the effect of essential oils on the control of soft rot of kale. Clove essential oil at 0.25%, lemongrass and palmarosa essential oils at 0.5%, melaleuca and orange essential oils at 0.75%, bergamot, rosemary, sage and ginger essential oils at 1% were evaluated for the in vitro inhibition of Pectobacterium carotovorum subsp. brasiliensis (Pcb) and control of soft rot of kale, sprayed 72 hours before or seven hours after inoculation. Clove, citronella, bergamot, rosemary, palmarosa, sage, melaleuca, and lemongrass oils completely inhibited the growth of Pcb. Lemongrass oil (0.5%) caused 0% of disease incidence (INC), providing 100% of disease control in both periods of inoculation. Clove oil (0.25%) showed a lower INC (25%) when applied after inoculation, providing a control percentage of 71.42%. The lemongrass and clove essential oils were analyzed by GC/FID (Gas Chromatography – Flame Ionization Detector) and by GC/MS (Gas Chromatography /Mass Spectrometer). The major components were eugenol (91,9%) for clove oil and citral, isometric mixture of neral (34,1%) and geranial (42,9%) for lemongrass oil. The Minimum inhibitory concentration (MIC) of lemongrass, clove oils and their major components (citral and eugenol, respectively) was determined by using a broth macrodilution technique, as well as they were evaluated at different concentrations on the control of soft rot of kale, sprayed according descriptions above. The MIC was 0.03125% for citral, and 0.0625 and 0.125% for lemongrass and clove oils, respectively. Eugenol didn't show MIC. Lemongrass oil at 0.125% (post-inoculation) and citral at 0.125% (pre and post-inoculation) provided the highest percentages of disease control (33.33, 50, and 100%, respectively). Clove oil at 0.125% (post-inoculation) showed better effectiveness than eugenol (0.25%), providing a percentage of disease control of 16.67%. Lemongrass and clove essential oils were the most effective in control of soft rot of kale, suggesting that these oils have a potential to be used as antibacterial agents.

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