scholarly journals Reaction of hybrids, inhibition in vitro and target spot control in cucumber

2011 ◽  
Vol 29 (3) ◽  
pp. 342-348 ◽  
Author(s):  
Adriana Teramoto ◽  
Marise C Martins ◽  
Luciene C Ferreira ◽  
Marcos G Cunha
Keyword(s):  
Mycelial Growth ◽  
Climatic Conditions ◽  
Control Measures ◽  
Corynespora Cassiicola ◽  
Horticultural Crop ◽  
Thiophanate Methyl ◽  
Chemical Treatments ◽  
Target Spot ◽  
Efficient Control

The fungus Corynespora cassiicola is the causal agent of target spot in cucumber. Under favorable climatic conditions it can cause serious damage in this horticultural crop. In Brazil, there exists not enough knowledge to determine efficient control measures to the disease. This investigation was carried out to evaluate: a) the reactions of nine cucumber hybrids to C. cassiicola; b) the sensibility of six isolates of C. cassiicola to fungicides in vitro (captan, chlorothalonil, mancozeb, azoxystrobin, difenoconazole, carbendazin, tebuconazole and thiophanate-methyl), used in concentrations of 0, 1, 10, 100 and 1,000 µg mL-1 of active ingredient and c) protective and curative chemical treatments with the same fungicides used in vitro in cucumber plants inoculated with C. cassiicola. The cucumber hybrids were evaluated using the scale of notes and diagrammatic of target spot severity. The more resistant hybrids to the pathogen were Taisho, Nikkey, Yoshinari and Safira. The difenoconazole fungicide caused the most mycelial growth inhibition (MGI) and showed the lowest ED50. Thiophanate-methyl was the worst fungicide, it did not inhibit the mycelial growth of the fungus. Azoxystrobin was the most efficient in controlling the disease, although it has to be registered in Ministry of Agriculture, Livestock and Food Supply in Brazil before its recommendation.

scholarly journals REACTION OF PAPAYA GENOTYPES TO TARGET SPOT AND ACTIVITY OF PLANT EXTRACTS AND Bacillus spp. ON Corynespora cassiicola

2018 ◽  
Vol 40 (1) ◽  
Author(s):  
Dannielle Silva Da Paz ◽  
José Ribamar Gusmão Araujo ◽  
Antônia Alice Costa Rodrigues ◽  
Erlen Keila Candido e Silva ◽  
Nathália Bandeira Diniz
Keyword(s):  
Plant Extracts ◽  
Mycelial Growth ◽  
Biological Control Agent ◽  
Circle Method ◽  
Inhibitory Effect ◽  
Natural Occurrence ◽  
Corynespora Cassiicola ◽  
Target Spot ◽  
Antagonistic Potential

ABSTRACT Papaya target-spot, caused by fungus Corynespora cassiicola presents a wide geographic distribution, causing leaf spots in several hosts. The aim of this research was to evaluate the behavior of papaya varieties and/or selections to the natural occurrence of target spot, and test the fungi toxic effect of neem, citronella and eucalyptus extracts, and fungi static effects of Bacillus isolates on the fungus C. cassiicola in vitro. To evaluate the natural occurrence of the disease in field, symptoms on leaves of 11 papaya varieties and/or selections have been assessed. The pathogenicity of isolates was verified by inoculation of plants in greenhouse. Neem, citronella and eucalyptus extracts were prepared at concentrations of 10, 15 and 20% and poured into Petri dishes containing C. cassiicola mycelium discs. For , Bacillusnine isolates were used, and the antagonistic potential was evaluated by the pairing of pathogen and isolate colonies by the circle method. Papaya varieties and/or selections presented all leaves with injury, and Canaan Sunrise Solo and Canaan Golden selections showed the greatest number of injuries per leaf, showing that papaya varieties and/or selections respond differently to the phytopathogen. All plant extracts tested showed inhibitory effect on the mycelial growth of C. cassiicola in vitro. Bacillus isolates showed an antagonistic potential on the mycelial growth of the fungus, with B. methylotrophicus (Iso 31 and Iso 41) being the most promising as a biological control agent. The results indicate that forms of alternative control of diseases are promising in the management of papaya target-spot.

scholarly journals Pharmacological Characteristics and Efficacy of Fluazinam Against Corynespora cassiicola, Causing Cucumber Target Spot in Greenhouses

Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2449-2454
Author(s):  
Tao Li ◽  
Qian Xiu ◽  
Jie Zhang ◽  
Jian Xin Wang ◽  
Ya Bing Duan ◽  
...  
Keyword(s):  
Spore Germination ◽  
Mycelial Growth ◽  
Plant Pathogens ◽  
Resistance Management ◽  
Cell Membrane Permeability ◽  
Corynespora Cassiicola ◽  
In Planta ◽  
Action Mode ◽  
Target Spot

Cucumber target spot, caused by Corynespora cassiicola, is a devastating fungal disease in greenhouses in China. Lack of resistant cultivars and unscientific use of fungicides aggravated the difficulty to manage this disease. In recent years, resistance of C. cassiicola to benzimidazoles, quinone outside inhibitors, and succinate dehydrogenase inhibitors has occurred in China. Here, we tested the fluazinam sensitivity distribution of 79 C. cassiicola isolates from different provinces in China based on mycelial growth inhibition. The EC50 values of fluazinam ranged from 0.1002 to 0.3129 µg/ml with a mean of 0.2136 ± 0.0495 µg/ml, and the sensitivity frequency was normally distributed (P = 0.2083, Shapiro–Wilk test). Meanwhile, the EC50 values for spore germination inhibition ranged from 0.0992 to 0.2278 µg/ml with a mean of 0.1499 ± 0.0504 µg/ml. This indicated that fluazinam exhibited an excellent in vitro fungicidal activity on both mycelial growth and spore germination. In addition, fluazinam also exhibited a good in planta control efficacy on detached cucumber leaves in the protective and curative assays. Moreover, the biological and physiological characteristics of C. cassiicola as affected by fluazinam were determined. Fluazinam not only significantly inhibited respiration and adenosine triphosphate production but also caused the increase of cell membrane permeability and the dysfunctions of cellular homeostasis. Interestingly, we found that fluazinam especially damaged vacuole structures, causing the redistribution of vacuole substances. Taken together, our findings provide not only essential references for resistance management of C. cassiicola but also interesting insights for further revealing the action mode of fluazinam against plant pathogens.

scholarly journals In vitro sensitivity of Corynespora cassiicola isolated from soybean to fungicides and field chemical control of target spot

2017 ◽  
Vol 43 (4) ◽  
pp. 281-289 ◽  
Author(s):  
Adriana Teramoto ◽  
Maurício Conrado Meyer ◽  
Nelson Dias Suassuna ◽  
Marcos Gomes da Cunha
Keyword(s):  
Growth Inhibition ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Field Experiments ◽  
Fungal Growth ◽  
Field Trials ◽  
Corynespora Cassiicola ◽  
In Vitro Sensitivity ◽  
Target Spot

ABSTRACT Soybean target spot (Corynespora cassiicola) has become an important disease in most soybean growing regions in Brazil. The sensitivity of 34 isolates of C. cassiicola to 11 fungicides was evaluated based on mycelial growth inhibition (boscalid, carbendazim, cyproconazole, fluopyram, fluxapyroxad, prothioconazole and thiophanate-methyl) or spore germination inhibition (azoxystrobin, picoxystrobin, pyraclostrobin and trifloxystrobin). In addition, the efficacy of five fungicides to control target spot was tested in four field trials carried out during three crop seasons: 2011/2012, 2012/2013 and 2013/2014. Fungal isolates were collected from soybean plants in several soybean growing areas in Brazil. The effective concentration of each fungicide to inhibit fungal growth or spore germination by 50% (EC50) was calculated for all isolates. Fluxapyroxad and prothioconazole provided the greatest mycelial growth inhibition and pyraclostrobin led to the lowest spore germination percentage, with the lowest EC50 values. At field experiments, cyproconazole and carbendazim showed target spot control ranging from 26% to 29%. On the other hand, fluxapyroxad and prothioconazole prevented an epidemic of the disease by 45% to 55%, respectively. In general, the efficacy of fungicides in the field reflected the in vitro sensitivity averages. Large sensitivity reduction was detected to benzimidazoles (MBC), indicating that this group of fungicides should no longer be used for target spot control. There was a negative and significant correlation (-0.265) between target spot severity and soybean yield. The pathogen showed variability in sensitivity to the fungicide groups carboxamides (SDHI), triazoles (DMI) and strobilurins (QoI), which denotes a high risk of selection for resistance.

High dilution of Belladonna affect the mycelial growth of Corynespora cassiicola in vitro

2021 ◽  
Vol 10 (36) ◽  
pp. 245-248
Author(s):  
Romulo Vinícios Fagan ◽  
Bruno Reis ◽  
Kátia Regina Freitas Schawan-Estrada ◽  
Carlos Moacir Bonato
Keyword(s):  
Mycelial Growth ◽  
Economic Losses ◽  
Distilled Water ◽  
Corynespora Cassiicola ◽  
Adequate Treatment ◽  
Membrane Pore ◽  
Organic Cultivation ◽  
High Dilutions ◽  
Millipore Membrane

Introduction: The target spot is a disease caused by fungus Corynespora cassiicola (Berk. & Curt.) Wei. This disease has occurred in several states of Brazil. It is a late season disease and causes economic losses in various crops such as soybeans [1]. Currently there is no adequate treatment for the control of C. cassiicola in organic cultivation of soybeans, since the application of fungicides for the control and management of diseases is not allowed by Brazilian legislation [2]. Thus, the purpose of this experiment was to test the effectiveness of high dilutions of Belladonna in vitro on mycelial growth of Corynespora cassiicola. Materials and Methods: The preliminary tests were conducted at the Laboratory of Plant Pathology, State University of Maringá (UEM). The fungal isolate of C. cassicola was obtained from Embrapa Soja. The fungus was peaked and grown on PDA (potato dextrose agar) maintained at 25°C ± 2 and 12h photoperiod. Belladonna dilutions (6, 12, 18, 24 and 30dH) were obtained according to the Brazilian Homeopathic Pharmacopoeia [3]. PDA culture medium plus Belladonna dilutions (6, 12, 24 and 30dH) beyond the control containing distilled water were placed in petri dishes after filtration through a Millipore membrane (pore diameter of 0.45µm ). After medium solidification, a disc of mycelium (4 mm diameter) of C. cassiicola was peaked towards the center of each plate and sealed with plastic wrap and then incubated at 25°C with 12h photoperiod. The mycelial growth was measured daily for 8 days. The control consisted of distilled water. The data were analyzed by ANOVA and means were compared by Scott-Knott test (P ≤ 0.05). Results and Discussion: All dilutions of Belladonna (6, 12, 24, 30dH) were effective (p

scholarly journals Estimation of the antifungal activity of some preparations against Diaporthe eres under in vitro conditions

2019 ◽  
Vol 72 (4) ◽  
Author(s):  
Ewa Dorota Król ◽  
Barbara Anna Abramczyk ◽  
Beata Zimowska ◽  
Ewa Dorota Zalewska
Keyword(s):  
Natural Products ◽  
Antifungal Activity ◽  
Mycelial Growth ◽  
Fruit Trees ◽  
Thiophanate Methyl ◽  
Natural Origin ◽  
Chemical Groups

Six fungicides from various chemical groups and two natural products, i.e., Biosept Active (grapefruit extract) and Beta-Chikol (chitosan) were tested in vitro against <em>Diaporthe eres</em> isolated from the shoots of fruit trees. The preparations were incorporated in PDA medium to provide final fungicide concentrations of 1, 10, and 100 g cm<sup>−3</sup>. Biosept Active concentrations of 0.05%, 0.075%, and 0.1%, and Beta-Chikol concentrations of 1%, 2%, and 2.5%, respectively. The antifungal activity of the preparations was evaluated based on mycelial growth of <em>D. eres</em> strains after 4 and 8 days of culture and changes in the morphological structures of the fungus. The highest antifungal activity was registered for thiophanate-methyl at all tested concentrations, followed by thiram, which showed the same activity but only at 100 g cm<sup>−3</sup>. Among the preparations of natural origin, Beta-Chikol was more effective against <em>D. eres</em> than Biosept Active. The effects achieved by the former preparation were comparable with those achieved by some of the most effective fungicides tested against <em>D. eres</em>.

Comparing the Fungicide Sensitivity of Sclerotinia sclerotiorum Using Mycelial Growth and Ascospore Germination Assays

Plant Disease ◽  
2021 ◽  
Author(s):  
Miller da Silva Lehner ◽  
Kaique Alves ◽  
Emerson Medeiros Del Ponte ◽  
Sarah Jane Pethybridge
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mode Of Action ◽  
Mycelial Growth ◽  
White Mold ◽  
Fungicide Sensitivity ◽  
Snap Bean ◽  
Thiophanate Methyl ◽  
Ascospore Germination ◽  
Sensitivity Tests

The infection of the floral tissues of snap bean and other crops by Sclerotinia sclerotiorum, the causative agent of white mold, is by ascospores. Irrespective of the fungicide mode of action being evaluated, in vitro fungicide sensitivity tests are conducted almost exclusively using mycelial growth assays. This is likely due to difficulties and time involved in sclerotial conditioning required to produce apothecia and ascospores. The objective of this research was to compare estimates of fungicide sensitivity between mycelial growth and ascospore germination assays for S. sclerotiorum. Sensitivity assays were conducted using serial doses of three fungicides commonly used to control white mold: boscalid, fluazinam, and thiophanate-methyl. A total of 27 isolates were evaluated in replicated trials conducted for each fungicide and assay type. The effective concentration to reduce mycelial growth or ascospore germination by 50% (EC50) was estimated for each isolate, fungicide, assay type, and trial. The median EC50 values obtained from ascospore germination assays were 52.7, 10.0, and 2.7 times higher than those estimated from the mycelial growth for boscalid, fluazinam, and thiophanate-methyl, respectively. No significant correlation was found between EC50 values estimated by the two methods. These findings highlight differences that may be important in evaluating the sensitivity of S. sclerotiorum given the fungicide mode of action and how they will be used in the field.

scholarly journals Efficient control of conidium germination, mycelial growth and early blight in tomato in vitro with essential oils under farm conditions

2016 ◽  
Vol 11 (43) ◽  
pp. 4401-4412
Author(s):  
L. M. Abreu C. ◽  
I. M. A. Feres C. ◽  
L. Furtado E. ◽  
C. Ming L. ◽  
O. M. Marques M. ◽  
...  
Keyword(s):  
Essential Oils ◽  
Mycelial Growth ◽  
Early Blight ◽  
Efficient Control ◽  
Conidium Germination

scholarly journals In Vitro Efficiency of Some Fungicides Against Neoscytalı̇dı̇um dı̇mı̇dı̇atum (Penz.) Crous and Slippers Causing Sudden Shoot Dry on Apricot Trees

2021 ◽  
Vol 9 (4) ◽  
pp. 797-802
Author(s):  
Aysun Eraslan Sür ◽  
Erçin Oksal
Keyword(s):  
Chemical Control ◽  
Mycelial Growth ◽  
Climatic Factors ◽  
In Vitro Studies ◽  
Thiophanate Methyl ◽  
Pests And Diseases ◽  
Neoscytalidium Dimidiatum

Turkey is known as a top producer and exporter of apricots, both fresh and dried. More than half of Turkey's apricot production is provided by Malatya province. There are many pests and diseases affecting apricots in addition to climatic factors such as frost and hail. Partial shoot drying and sudden drying in apricot orchards have increased in recent years. In this study, it was aimed to determine the chemical control possibilities of Neoscytalidium dimidiatum (Penz.) Crous &Slippers, which is one of the fungal agents that cause partial branch drying and sudden drying in apricot orchards in Malatya province by in vitro studies. For this purpose, Kale 4-C isolate of N. dimidiatum collected from Malatya in a previous study was used. Mycelial growth of N. dimidiatum Kale 4-C isolate in PDA were observed in 0 (control), 0.01, 0.03, 0.1, 1, 3, 10, 30 ve 100 μg/mL concentrations of Azoxystrobin 250g/L, Trifloxystrobin %50, Tebuconazole %25, Floupyram 200 g/L+Tebuconazole 200 g/L, Cyprodinil+Fludioxonil %37.5+25, %70 Thiophanate-Methyl and 400 g/L Phosphorous acide fungicides applications. As a result of the study, Floupyram 200g/L+Tebuconazole 200g/L ve Cyprodinil+Fludioxonil %37.5+25 fungicides effectively inhibited the mycelial growth of the fungus.

scholarly journals Sensitivity of Phaeomoniella chlamydospora to fungicides in vitro

2001 ◽  
Vol 54 ◽  
pp. 225-228 ◽  
Author(s):  
M.V. Jaspers
Keyword(s):  
Radial Growth ◽  
Mycelial Growth ◽  
Potential Role ◽  
Benzimidazole Fungicides ◽  
Thiophanate Methyl ◽  
Phaeomoniella Chlamydospora ◽  
Dmi Fungicides ◽  
Vine Decline

Phaeomoniella chlamydospora has recently been shown to cause Petri vine decline in young grapevines No recommendations are available for management of the disease using fungicides In this study 22 fungicides were tested for their effect on the radial growth of three field isolates of P chlamydospora Systemic fungicides inhibited mycelial growth of the fungus at similar concentrations to those reported for other fungi The DMI fungicides cyproconazole bitertanol tebuconazole fenarimol myclobutanil and prochloraz gave EC50 values for reduction of mycelial growth of less than 03 mg/litre whereas triforine gave an EC50 value of 26 mg/litre For the benzimidazole fungicides benomyl carbendazim and thiophanate methyl the EC50 values were less than 04 mg/litre For the anilopyrimidines pyrimethanil and cyprodinil/fludioxonil (Switch) EC50 values were less than 002 mg/litre For the contact fungicides tested EC50 values were higher than those reported for similar fungi The potential role of the fungicides in disease management is discussed

scholarly journals Plant Biostimulants: New Insights Into the Biological Control of Verticillium Wilt of Olive

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana López-Moral ◽  
Carlos Agustí-Brisach ◽  
Antonio Trapero
Keyword(s):  
Biological Control ◽  
Verticillium Wilt ◽  
Mycelial Growth ◽  
Foliar Application ◽  
Control Measures ◽  
The Other ◽  
Limiting Factor ◽  
In Planta ◽  
Disease Reduction

Verticillium wilt of olive (Olea europaea subsp. europaea L.) (VWO), caused by the hemibiotrophic soil-borne fungus Verticillium dahliae Kleb., is considered the major limiting factor of this crop in Mediterranean-type climate regions of the world. The absence of effective chemical treatments makes the control of the disease difficult. In this way, the use of biostimulants and host plant defense inducers seems to be one of the most promising biological and eco-friendly alternatives to traditional control measures. Thus, the main goal of this study was to evaluate the effect of 32 products, including amino acids, micronutrients, microorganisms, substances of natural origin, copper complex-based products, and organic and inorganic salts against the disease under controlled conditions. To this end, their effects on mycelial growth and microsclerotia (MS) inhibition of V. dahliae were evaluated by means of dual cultures or by sensitivity tests in vitro as well as on disease progression in planta. Wide ranging responses to the pathogen and disease reduction levels were observed among all the products tested, suggesting multiple modes of action. Copper-based products were among the most effective for mycelial growth and MS inhibition, whereas they did not show an important effect on the reduction of disease severity in planta. Phoma sp. and Aureobasidium pullulans were the most effective in disease reduction in planta with foliar application. On the other hand, two phosphite salts, one with copper and the other with potassium, were the most effective in disease reduction in planta when they were applied by irrigation, followed by A. pullulans and Bacillus amyloliquefaciens. This study will be useful to select the best candidates for future studies, contributing significantly to new insights into the current challenge of the biological control of VWO.

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