scholarly journals Evaluation of Fungicides and Management Strategies against Cercospora Leaf Spot of Olive Caused by Pseudocercospora cladosporioides

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 271
Author(s):  
Joaquín Romero ◽  
Arantxa Ávila ◽  
Carlos Agustí-Brisach ◽  
Luis F. Roca ◽  
Antonio Trapero
Keyword(s):  
Leaf Spot ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Conidial Germination ◽  
Field Conditions ◽  
Cercospora Leaf Spot ◽  
Wide Range ◽  
Traditional Strategy ◽  
Mediterranean Conditions

Cercospora leaf spot of olive (CLSO), caused by Pseudocercospora cladosporioides, is one of the most important foliar diseases of olives worldwide. This study aimed to evaluate the effect of a wide range of fungicides on mycelial growth and conidial germination of P. cladosporioides in vitro, and to evaluate the effect of several fungicides, application timings and management strategies (conservative and risky) to control CLSO under field conditions. Of the studied fungicides, strobilurin compounds and benomyl were the most effective active ingredients, followed by folpet, captan and maneb, in inhibiting mycelial growth and conidial germination. The pyraclostrobin + boscalid treatment was effective under field conditions, even without the application of supplementary copper. Treatments conducted in October or March were more effective than those conducted in May. Management strategies based on the author’s experience reduced copper applications up to 32.0% and 50.0% (conservative and risky strategy, respectively) in comparison to the reduction with the traditional strategy, without increasing CLSO incidence. This work provides useful information about effective formulations against CLSO and a reduction in unnecessary fungicide applications in an effort to implement IPM in olive orchards under Mediterranean conditions.

Evaluation of Fungicides to Control Loquat Scab Caused by Fusicladium eriobotryae

2014 ◽  
Vol 15 (3) ◽  
pp. 88-91 ◽  
Author(s):  
Elisa González-Domínguez ◽  
José M. Rodríguez-Reina ◽  
José García-Jiménez ◽  
Josep Armengol
Keyword(s):  
Disease Control ◽  
Disease Severity ◽  
Ammonium Chloride ◽  
Post Infection ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Conidial Germination ◽  
Copper Oxychloride

Loquat scab caused by Fusicladium eriobotryae is the main disease affecting the loquat crop. The fungus can infect leaves and fruits, reducing the marketable quality of the latter. The efficacy of 13 fungicides against F. eriobotryae was evaluated in vitro by testing their effect on mycelial growth and conidial germination. Boscalid, chlorothalonil, didecyldimethyl ammonium chloride, and pyraclostrobin were able to reduce both conidial germination and mycelial growth of F. eriobotryae. Moreover, a growth chamber experiment was conducted to determine the pre- and post-infection activity of five selected fungicides. Difenoconazole and pyraclostrobin applications resulted in relative disease severity (RDS) values lower than 5%, even when applied 7 days before or after the inoculation. Boscalid and mancozeb applied before F. eriobotryae inoculation resulted in RDS values lower than 15%, whereas values up to 20% of RDS were obtained with copper oxychloride. Results indicate that the fungicides currently recommended in southeastern Spain against loquat scab provide adequate disease control, and new active ingredients could be added to the present management strategies. Accepted 7 May 2014. Published 27 July 2014.

scholarly journals Evaluation of various plant extracts against the early blight disease of tomato plants under greenhouse and field conditions

2012 ◽  
Vol 48 (No. 2) ◽  
pp. 74-79 ◽  
Author(s):  
S.M.A. Nashwa ◽  
K.A.M. Abo-Elyousr
Keyword(s):  
Disease Severity ◽  
Plant Extracts ◽  
Mycelial Growth ◽  
Early Blight ◽  
Field Conditions ◽  
Nerium Oleander ◽  
Tomato Plants ◽  
Infected Control ◽  
Blight Disease

The antimicrobial activity of six plant extracts from Ocimum basilicum (Sweat Basil), Azadirachta indica (Neem), Eucalyptus chamadulonsis (Eucalyptus), Datura stramonium (Jimsonweed), Nerium oleander (Oleander), and Allium sativum (Garlic) was tested for controlling Alternaria solani in vitro and in vivo. In in vitro study the leaf extracts of D. stramonium, A. indica, and A. sativum at 5% concentration caused the highest reduction of mycelial growth of A. solani (44.4, 43.3 and 42.2%, respectively), while O. basilicum at 1% and 5% concentration and N. oleander at 5% concentration caused the lowest inhibition of mycelial growth of the pathogen. In greenhouse experiments the highest reduction of disease severity was achieved by the extracts of A. sativum at 5% concentration and D. stramonium at 1% and 5% concentration. The greatest reduction of disease severity was achieved by A. sativum at 5% concentration and the smallest reduction was obtained when tomato plants were treated with O. basilicum at 1% and 5% concentration (46.1 and 45.2 %, respectively). D. stramonium and A. sativum at 5% concentration increased the fruit yield by 76.2% and 66.7% compared to the infected control. All treatments with plant extracts significantly reduced the early blight disease as well as increased the yield of tomato compared to the infected control under field conditions.

scholarly journals Bacterial Inhibition on Beauveria bassiana Contributes to Microbiota Stability in Delia antiqua

2021 ◽  
Vol 12 ◽  
Author(s):  
Fangyuan Zhou ◽  
Yunxiao Gao ◽  
Mei Liu ◽  
Letian Xu ◽  
Xiaoqing Wu ◽  
...  
Keyword(s):  
Beauveria Bassiana ◽  
Mycelial Growth ◽  
Bacterial Species ◽  
Management Strategies ◽  
Underlying Mechanism ◽  
Conidial Germination ◽  
Delia Antiqua ◽  
Bacterial Microbiota ◽  
Fungal Microbiota ◽  
Microbial Environment

Given the multiple roles of associated microbiota in improving animal host fitness in a microbial environment, increasing numbers of researchers have focused on how the associated microbiota keeps stable under complex environmental factors, especially some biological ones. Recent studies show that associated microbiota interacts with pathogenic microbes. However, whether and how the interaction would influence microbiota stability is limitedly investigated. Based on the interaction among Delia antiqua, its associated microbiota, and one pathogen Beauveria bassiana, the associated microbiota's response to the pathogen was determined in this study. Besides, the underlying mechanism for the response was also preliminarily investigated. Results showed that B. bassiana neither infect D. antiqua larvae nor did it colonize inside the associated microbiota, and both the bacterial and fungal microbiota kept stable during the interaction. Further experiments showed that bacterial microbiota almost completely inhibited conidial germination and mycelial growth of B. bassiana during its invasion, while fungal microbiota did not inhibit conidial germination and mycelial growth of B. bassiana. According to the above results, individual dominant bacterial species were isolated, and their inhibition on conidial germination and mycelial growth of B. bassiana was reconfirmed. Thus, these results indicated that bacterial instead of fungal microbiota blocked B. bassiana conidia and stabilized the associated microbiota of D. antiqua larvae during B. bassiana invasion. The findings deepened the understanding of the role of associated microbiota–pathogen microbe interaction in maintaining microbiota stability. They may also contribute to the development of novel biological control agents and pest management strategies.

scholarly journals Saprophytic microorganisms with potential for biological control of Botrytis cinerea on Geraldton waxflower flowers

2001 ◽  
Vol 41 (5) ◽  
pp. 697 ◽  
Author(s):  
D. R. Beasley ◽  
D. C. Joyce ◽  
L. M. Coates ◽  
A. H. Wearing
Keyword(s):  
Botrytis Cinerea ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Conidial Germination ◽  
Pseudomonas Sp ◽  
Trichoderma Spp ◽  
Fusarium Sp ◽  
Flower Abscission ◽  
Germ Tube Elongation

Saprophytic bacteria, yeasts and filamentous fungi were isolated from Geraldton waxflower flowers and screened to identify potential antagonism towards Botrytis cinerea. Isolates from other sources (e.g. avocado) were also tested. Isolates were initially screened in vitro for inhibition of B. cinerea conidial germination, germ tube elongation and mycelial growth. The most antagonistic bacteria, yeasts and fungi were selected for further testing on detached waxflower flowers. Conidia of the pathogen were mixed with conidia or cells of the selected antagonists, co-inoculated onto waxflower flowers, and the flowers were sealed in glass jars and incubated at 20˚C. The number of days required for the pathogen to cause flower abscission was determined. The most antagonistic bacterial isolate, Pseudomonas sp. 677, significantly reduced conidial germination and retarded germ tube elongation of B. cinerea. None of the yeast or fungal isolates tested was found to significantly reduce conidial germination or retard germ tube elongation, but several significantly inhibited growth of B. cinerea. Fusarium sp., Epicoccum sp. and Trichoderma spp. were the most antagonistic of these isolates. Of the isolates tested on waxflower, Pseudomonas sp. 677 was highly antagonistic towards B. cinerea and delayed waxflower abscission by about 3 days. Trichoderma harzianum also significantly delayed flower abscission. However, as with most of the fungal antagonists used, inoculation of waxflower flowers with this isolate resulted in unsightly mycelial growth.

Screening of Existing and New Boxwood Cultivars for Disease Resistance and In Vitro Fungicide Screening to Manage Boxwood Dieback Caused by Colletotrichum theobromicola

2021 ◽  
Author(s):  
Harleen Kaur ◽  
Monique DeSouza ◽  
Raghuwinder "Raj" Singh
Keyword(s):  
Active Ingredient ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Management Practices ◽  
Management Strategies ◽  
Host Susceptibility ◽  
Germination Inhibition ◽  
Industry Professionals ◽  
The U.S

Boxwood is one of the most common and widely planted perennial ornamentals in both home gardens and commercial landscapes. Recently reported boxwood dieback, a fungal disease caused by Colletotrichum theobromicola, has been spreading at an alarming rate within the U.S. Boxwood breeders, nursery growers, and landscape professionals have shown great concerns regarding the lack of effective management practices. Therefore, the primary objectives of this study were to devise effective disease management strategies including screening cultivars to determine their susceptibility to boxwood dieback and screening various fungicides to determine their effectiveness in managing the disease. Host range studies were conducted by screening a wide variety of boxwood cultivars under greenhouse conditions. Although, boxwood cultivar ‘Little Missy’ showed much delayed symptom expression as compared to rest of the cultivars but none of the 11 cultivars were found to be resistance to boxwood dieback. In vitro screening of nine fungicides was conducted to determine mycelial growth as well as spore germination inhibition of eight isolates of C. theobromicola collected from eight states in the U.S. Of the nine fungicides, difenoconazole+pydiflumetofen showed maximum mycelial growth and spore germination inhibition at 1 ppm active ingredient followed by fluxapyroxad+pyraclostrobin, and pyraclostrobin+boscalid at 5 ppm active ingredient. Azoxystrobin+benzovindiflupyr significantly inhibited mycelial growth at 1 ppm but reduced spore germination at 10 ppm active ingredient. This study provides the boxwood industry professionals with critical and applied information pertaining to host susceptibility and fungicide efficacy to effectively mitigate boxwood dieback and to reduce its further spread.

scholarly journals  Leaf spot and dieback of Buxus caused by Cylindrocladium buxicola

2013 ◽  
Vol 49 (No. 4) ◽  
pp. 165-168 ◽  
Author(s):  
I. Šafránková ◽  
L. Holková ◽  
M. Kmoch
Keyword(s):  
Dna Sequencing ◽  
Leaf Spot ◽  
Mycelial Growth ◽  
Leaf Blight ◽  
Visual Symptoms ◽  
Buxus Sempervirens ◽  
Microscopic Features ◽  
South Moravia ◽  
Molecular Characters

Leaf blight symptoms were observed on potted box plants (Buxus sempervirens cv. Suffruticosa and B. microphylla) in a nursery in South Moravia in August 2010. These symptoms were suggestive of box blight on Buxus spp. Characteristics of the visual symptoms, microscopic features, and identification of the isolates using DNA sequencing are described. The causal agent was isolated and identified as Cylindrocladium buxicola Henricot by means of morphological, cultural, and molecular characters. The effect of five commercial fungicides on C. buxicola in vitro was studied. The most effective fungicides (kresoxim-methyl, azoxystrobin, and mancozeb) inhibited conidia germination and mycelial growth (kresoxim-methyl, myclobutanil, and penconazole) of C. buxicola more than 96%.  

scholarly journals Control of Sphaeropsis Rot in Stored Apple Fruit Caused by Sphaeropsis pyriputrescens with Postharvest Fungicides

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1075-1079 ◽  
Author(s):  
C. L. Xiao ◽  
Y. K. Kim ◽  
R. J. Boal
Keyword(s):  
Mycelial Growth ◽  
Disease Incidence ◽  
Apple Fruit ◽  
Conidial Germination ◽  
Fruit Rot ◽  
Mitigation Measures ◽  
The Mean ◽  
Rot Disease ◽  
Sphaeropsis Rot

Sphaeropsis rot caused by Sphaeropsis pyriputrescens is a recently reported postharvest fruit rot disease of apple grown in Washington State. The objective of this study was to develop chemical-based mitigation measures for Sphaeropsis rot in stored apple fruit. To determine in vitro sensitivity of S. pyriputrescens to the three registered postharvest fungicides thiabendazole, fludioxonil, and pyrimethanil, 30 isolates of S. pyriputrescens obtained from various sources were tested for mycelial growth and conidial germination on fungicide-amended media. Golden Delicious apple fruit were inoculated with the pathogen in the orchard at 2 or 5 weeks before harvest. After harvest, fruit were either nontreated or dipped in thiabendazole, fludioxonil, or pyrimethanil solutions, stored at 0°C, and monitored for decay development for up to 9 months after harvest. The mean effective concentration of a fungicide that inhibits mycelial growth or spore germination by 50% relative to the nonamended control (EC50) values of thiabendazole, fludioxonil, and pyrimethanil on mycelial growth were 0.791, 0.0005, and 2.829 μg/ml, respectively. Fludioxonil and pyrimethanil also were effective in inhibiting conidial germination of the fungus with EC50 values of 0.02 μg/ml for fludioxonil and 5.626 μg/ml for pyrimethanil. All three postharvest fungicides applied at label rates immediately after harvest were equally effective in controlling Sphaeropsis rot in stored apple fruit, reducing disease incidence by 92 to 100% compared with the nontreated control. The results indicated that Sphaeropsis rot may be effectively controlled by the currently registered postharvest fungicides thiabendazole, fludioxonil, and pyrimethanil.

scholarly journals Assessment of Plant Extracts and their In vitro Efficacy against Potato Early Blight Incited by Alternaria solani

2021 ◽  
Vol 15 (3) ◽  
pp. 1591-1601
Author(s):  
Sumit Kumar ◽  
Ram Chandra ◽  
Lopamudra Behera
Keyword(s):  
Plant Extracts ◽  
Mycelial Growth ◽  
Early Blight ◽  
Plant Pathogens ◽  
Alternaria Solani ◽  
Significant Inhibition ◽  
Conidial Germination ◽  
Potato Dextrose Agar Medium ◽  
Percent Concentration

Botanicals obtained from the plants are well known for the suppression of inimical plant pathogens. The present study explores the efficacy of five locally available plant extracts for their antifungal activity against the early blight of potato incited by Alternaria solani. The extracts include Datura stramonium, Allium sativum, Azadirachta indica, Eucalyptus globulus, and Lantana camara. All extracts reduced mycelial growth and conidial germination of A. solani. In vitro studies showed that extracts obtained from A. sativum and A. indica have significant inhibition of mycelial growth of A. solani (88.80 and 86.62 percent) at 20 percent concentration. Higher concentrations of A. sativum extract caused a higher reduction of A. solani radial growth on potato dextrose agar medium. Extracts obtained from A. sativum and A. indica at 20 percent concentration, were found most effective for inhibition of conidial germination (85.50 and 80.04 percent) respectively of A. solani. Observations by scanning electron microscope (SEM) showed dramatic alteration in A. solani hyphae collapsed and spores shrinked when treated with extract of A. sativum at a 20 per cent concentration. The qualitative and quantitative analysis of various phytochemicals like flavonoids, alkaloids, saponins, tannins, steroids, terpenoids, glycosides, and phenols was showed A. sativum extract better than all the other plant extracts. Observation also revealed that 20 percent concentration of garlic extract has potential to inhibit to A. solani.

Assessment of quinone outside inhibitor sensitivity and frogeye leaf spot race of Cercospora sojina in Georgia soybean

Plant Disease ◽  
2021 ◽  
Author(s):  
Bennett Harrelson ◽  
Bikash Ghimire ◽  
Robert Kemerait ◽  
Albert Culbreath ◽  
Zenglu Li ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Fungicide Resistance ◽  
Mycelial Growth ◽  
The United States ◽  
In Vitro Assays ◽  
Cercospora Sojina ◽  
Quinone Outside Inhibitor ◽  
Frogeye Leaf Spot ◽  
Differential Cultivars

Frogeye leaf spot (FLS), caused by the fungal pathogen Cercospora sojina K. Hara, is a foliar disease of soybean (Glycine max L. (Merr.)) responsible for yield reductions throughout the major soybean producing regions in the world. In the United States, management of FLS relies heavily on the use of resistant cultivars and in-season fungicide applications, specifically within the class of quinone outside inhibitors (QoIs), which has resulted in the development of fungicide resistance in many states. In 2018 and 2019, 80 isolates of C. sojina were collected from six counties in Georgia and screened for QoI fungicide resistance using molecular and in vitro assays, with resistant isolates being confirmed from three counties. Additionally, 50 isolates, including a “baseline isolate” with no prior fungicide exposure, were used to determine the percent reduction of mycelial growth to two fungicides, azoxystrobin and pyraclostrobin, at six concentrations: 0.0001, 0.001, 0.01, 0.1, 1, and 10 g ml-1. Mycelial growth observed for resistant isolates varied significantly from both the sensitive isolates and the baseline isolate for azoxystrobin concentrations of 10, 1, 0.1, and 0.01 g ml-1 and for pyraclostrobin concentrations of 10, 1, 0.1, 0.01 and 0.001 g ml-1. Moreover, 40 isolates were used to evaluate pathogen race on six soybean differential cultivars by assessing susceptible or resistant reactions. Isolate reactions suggested 12 races of C. sojina present in Georgia, four of which have not been previously described. Species richness indicators (rarefaction and abundance-based coverage estimator - ACE) indicated that within-county C. sojina race numbers were undersampled in the present study, suggesting the potential for the presence of either additional undescribed races or known but unaccounted for races in Georgia. However, no isolates were pathogenic on differential cultivar ‘Davis’, carrying the Rcs3 resistance allele, suggesting the gene is still an effective source of resistance in Georgia.

Current Overviews on COVID-19 Management Strategies

2021 ◽  
Vol 22 ◽  
Author(s):  
Pankaj Kumar Rai ◽  
Zeba Mueed ◽  
Abhiroop Chowdhury ◽  
Ravi Deval ◽  
Dinesh Kumar ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Management Strategies ◽  
Symptomatic Treatment ◽  
Diagnostic Methods ◽  
Antibody Detection ◽  
Modes Of Action ◽  
Prospective Control ◽  
Wide Range

The coronavirus pandemic has hit the world lately and caused acute respiratory syndrome in humans. The causative agent of the disease was soon brought to focus by scientists as SARS-CoV-2 and later called a novel coronavirus by the general public. Due to the severity and rapid spread of the disease, WHO classifies the COVID-19 pandemic as the 6th public health emergency even after taking efforts like worldwide quarantine and restrictions. Since only symptomatic treatment is available, the best way to control the spread of the virus is by taking preventive measures. Various types of antigen/antibody detection kits and diagnostic methods are available for the diagnosis of COVID-19 patients. In recent years, various phytochemicals and repurposing drugs are showing a broad range of anti-viral activities with different modes of action have been identified. Repurposing drugs such as arbidol, hydroxychloroquine, chloroquine, lopinavir, favipiravir, remdesivir, hexamethylene amiloride, and dexamethasone, tocilizumab, interferon-β, neutralizing antibodies exhibit in vitro anti-coronaviral properties by inhibiting multiple processes in the virus life cycle. Various research groups are involved in drug trials and vaccine development. Plant-based anti-viral compounds such as baicalin, calanolides, curcumin, oxymatrine, matrine, and resveratrol exhibit different modes of action against a wide range of positive/negative sense-RNA/DNA virus, and future researches need to be conducted to ascertain their role, use in managing SARS-CoV-2. Thus, this article is an attempt to review the current understanding of COVID-19 acute respiratory disease and summarize its clinical features with their prospective control and various aspects of the therapeutic approach.

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