scholarly journals Sensitivity of Ascochyta Species Infecting Pea, Lentil, and Chickpea to Boscalid, Fluxapyroxad, and Prothioconazole

Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1254-1260 ◽  
Author(s):  
Erin Lonergan ◽  
Julie Pasche ◽  
Linnea Skoglund ◽  
Mary Burrows
Keyword(s):  
Mycelial Growth ◽  
Ascochyta Blight ◽  
Fungal Growth ◽  
In Vitro Assays ◽  
Mycosphaerella Pinodes ◽  
Fungicide Sensitivity ◽  
Ascochyta Pinodes ◽  
Management Recommendations ◽  
Control Failures

Management of Ascochyta blight in pea, lentil, and chickpea relies on repeated fungicide applications, which has led to development of fungicide resistance and disease control failures in some systems. In vitro assays were conducted to determine baseline fungicide sensitivity in Mycosphaerella pinodes (Ascochyta pinodes), A. lentis, and A. rabiei populations to the demethylation-inhibiting fungicide prothioconazole and the succinate dehydrogenase-inhibiting fungicides boscalid and fluxapyroxad by determining the effective concentration at which 50% of germination or fungal growth was inhibited (EC50). Mean boscalid EC50 values from conidial germination assays were 0.669, 0.639, and 0.171 μg/ml and from mycelial growth assays were 0.258, 0.791, and 0.443 μg/ml for M. pinodes, A. lentis, and A. rabiei, respectively. Mean fluxapyroxad EC50 values were 0.050, 0.763, and 0.057 μg/ml for M. pinodes, A. lentis, and A. rabiei, respectively. Mean baseline EC50 values for prothioconazole with mycelial growth were 0.541, 0.604, and 0.283 μg/ml for M. pinodes, A. lentis, and A. rabiei, respectively. A single discriminatory fungicide concentration of 1 μg/ml was selected for all species. Established sensitivity profiles and discriminatory concentrations will be used to monitor sensitivity shifts in populations of Ascochyta spp. and to make effective disease management recommendations.

scholarly journals Fungicide Efficacy Against Calonectria pseudonaviculata, Causal Agent of Boxwood Blight

Plant Disease ◽  
2014 ◽  
Vol 98 (1) ◽  
pp. 99-102 ◽  
Author(s):  
J. A. LaMondia
Keyword(s):  
Mycelial Growth ◽  
Fungal Growth ◽  
Conidial Germination ◽  
In Vitro Assays ◽  
Active Ingredients ◽  
Action Committee ◽  
Selection For ◽  
Stem Lesions ◽  
Fungicide Insensitivity

Calonectria pseudonaviculata causes leaf spot and stem lesions resulting in defoliation and dieback of boxwood. Fungicides representing 20 different active ingredients from 13 different Fungicide Resistance Action Committee groups were evaluated for their effects on conidial germination and mycelial growth using in vitro assays, and the concentration that suppressed fungal growth to 15% of that on unamended media (EC85) values were determined. A number of fungicides strongly inhibited mycelial growth of C. pseudonaviculata. Four demethylation inhibitor fungicides had EC85 values of 1.2 μg a.i./ml or less. Thiophanate-methyl, fludioxonil, pyraclostrobin, trifloxystrobin, kresoxim-methyl, mancozeb, and chlorothalonil also had activity against mycelial growth. Fludioxonil + cyprodinil had a lower EC85 than the same rate of fludioxonil alone, suggesting that cyprodinil had activity against mycelial growth. Fungicides that inhibited C. pseudonaviculata conidial germination include pyraclostrobin, trifloxystrobin, and kresoxim-methyl as well as fludioxonil, mancozeb, chlorothalonil, and boscalid. Quinoxyfen, etridiazole, fenhexamid, hymexazol, famoxadone, and cymoxanil did not inhibit either C. pseudonaviculata conidial germination or mycelial growth. In comparison with values found in the literature, EC50 values for kresoxim-methyl were up to 10 times higher than reported previously, suggesting that fungicide insensitivity may have developed. Protectant fungicides with activity against conidial germination and systemic fungicides with activity against mycelial growth, such as those identified here, may be complementary to achieve the high levels of pathogen management required for control of this disease. In addition, multiple fungicide active ingredients from different mode-of-action groups used in mixtures or over time may also act to slow selection for fungicide insensitivity.

scholarly journals Biological Safety Evaluation of 99mTc-DTPA-Ketoconazole for Diagnosis of Fungal Infection

2017 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Maula Eka Sriyani ◽  
Hendris Wongso ◽  
Eva Maria Widyasari ◽  
Rizky Juwita Sugiharti ◽  
Iim Halimah ◽  
...  
Keyword(s):  
Single Dose ◽  
Fungal Infection ◽  
Radiochemical Purity ◽  
Safety Evaluation ◽  
Fungal Growth ◽  
In Vitro Assays ◽  
Toxic Response ◽  
Biological Safety ◽  
Safety Parameters

Infectious diseases have become one of the leading cause of mortality around the world, including in the Southeast Asia. One of the microbial that cause infection is fungi. Occasionally, deep-seated fungal infection is difficult to detect using conventional diagnosis methods and therefore leads to inaccurate detection. Our previous research was conducted in order to obtain the labeled compound of <sup>99m</sup>Tc-DTPA-Ketoconazole with a high radiochemical purity (98.40 ± 0.86%). Moreover, the in-vitro assays showed that <sup>99m</sup>Tc-DTPA-Ketoconazole can potentially bind to Candida albicans. On the other hand, in clinical routine use, diagnostic kit should be safe for the patients. Consequently, this research was conducted to determine the biological safety parameters of <sup>99m</sup>Tc-DTPA-Ketoconazole on the animal study, including single dose and acute toxicity test, sterility, and apirogenicity test. The results showed that both the single dose at 34.6 μCi and dose until 149 times of the single dose did not stimulate the toxic response to the animals. In addition, the sterility data revealed that there was no microbial growth after 7 days of incubation at 37°C as well as fungal growth after 14 days of incubation at 25°C. Furthermore, the apirogenicity test using rabbits revealed that there was no increase in temperature more than 0.6°C for each animal and not more than 1.5°C of total increase of temperature for all the animals. It is concluded that the <sup>99m</sup>Tc-DTPA-Ketoconazole is satisfy the requirements of biological safety of a radiopharmaceutical and therefore was acceptable for fungal detection in nuclear medicine.

scholarly journals In vitro fungitoxic potential of Lippia gracilis (Schauer) essential oil against phytopathogens

2020 ◽  
pp. 667-674
Author(s):  
Kevison Romulo da Silva França ◽  
Flavia Mota de Figueredo Alves ◽  
Tiago Silva Lima ◽  
Alda Leaby dos Santos Xavier ◽  
Plínio Tércio Medeiros de Azevedo ◽  
...  
Keyword(s):  
Essential Oil ◽  
Mycelial Growth ◽  
Fungal Growth ◽  
Fungal Species ◽  
Phytopathogenic Fungi ◽  
Negative Control ◽  
Growth Speed ◽  
Randomized Design

This study evaluates the in vitro effects of Lippia gracilis essential oil on the mycelial growth of phytopathogenic fungi. Experiments were carried out using a completely randomized design to assess the effects of eight treatments. Five replicates were evaluated for each experimental group. The essential oil was incorporated into the potato dextrose culture medium and poured into Petri dishes. Treatments were comprised of different concentrations of the oil (0.0125, 0.025, 0.05, 0.1, and 0.2%), a negative control (0.0%), and two positive controls (commercial fungicides). The plates were inoculated with fungi including Colletotrichum gloeosporioides, C. musae, C. fructicola, C. asianum, Alternaria alternata, A. brassicicola, Fusarium solani, F. oxysporum f. sp. cubense, and Lasiodiplodia theobromae and were incubated for seven days at 27 ± 2°C. The following variables were measured to verify the differences observed among treatments: percentage of mycelial growth inhibition and index of mycelial growth speed. All concentrations of L. gracilis oil inhibited the mycelial growth of the fungal species evaluated. The complete inhibition was observed between concentrations of 0.0125 and 0.1%. Treatment with oil inhibited fungal growth with similar, or even greater, efficiency than commercial fungicides.. We recommend the development of in vivo tests to verify whether L. gracilis essential oil can protect against fungal disease in live plants.

scholarly journals Relationship Between Fungicide Sensitivity and Control of Gummy Stem Blight of Watermelon Under Field Conditions

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1780-1784 ◽  
Author(s):  
A. Thomas ◽  
D. B. Langston ◽  
H. F. Sanders ◽  
K. L. Stevenson
Keyword(s):  
Fungicide Resistance ◽  
Field Experiments ◽  
In Vitro Assays ◽  
Didymella Bryoniae ◽  
Fungicide Sensitivity ◽  
Thiophanate Methyl ◽  
Stem Blight ◽  
Gummy Stem Blight ◽  
And Control

Gummy stem blight (GSB), caused by the fungus Didymella bryoniae, is the most destructive disease of watermelon and is managed primarily with fungicides. D. bryoniae has developed resistance to many fungicides that were once very effective, including azoxystrobin, boscalid, and thiophanate-methyl. Field experiments were conducted in Tifton (TN) and Reidsville (RV), GA in 2009 and 2010 to establish a relationship between frequency of resistance to a fungicide based on in vitro assays and its efficacy in the management of GSB. Frequency of resistance to boscalid, thiophanate-methyl, and azoxystrobin was >0.80 in isolates collected from nontreated plots in both locations and years. All isolates collected after six applications of boscalid, thiophanate-methyl, or azoxystrobin were resistant to the respective fungicide. All isolates collected from treated and nontreated plots were sensitive to tebuconazole and difenoconazole. GSB severity was assessed on a weekly basis from 63 days after planting. GSB severity in plots treated with boscalid, thiophanate-methyl, or azoxystrobin was not significantly different from that in the nontreated plots (39%, TN-2009; 45%, TN-2010; and 16%, RV-2010). GSB severity in tebuconazole-treated plots (27%, TN-2009; 14%, TN-2010; and 4%, RV-2010) was significantly lower than all other treatments and the nontreated control. There was a consistent negative association between frequency of fungicide resistance and disease control in the field. Thus, knowledge of the frequency of fungicide resistance in the pathogen population will be helpful in selecting the most effective fungicides for the management of GSB in watermelon fields.

scholarly journals POTENTIAL OF PLANT EXTRACTS AND FUNGICIDES FOR MANAGING FUSARIUM OXYSPORUM F. SPLYCOPERSICI

2018 ◽  
Vol 30 (1) ◽  
pp. 75 ◽  
Author(s):  
Gul B. Poussio ◽  
Manzoor A. Abro ◽  
Jamal U. D. Hajano ◽  
Muhammad I. Khaskheli ◽  
Khalid I. Rajput ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Block Design ◽  
Fungal Growth ◽  
Tomato Crop ◽  
Randomized Block Design ◽  
Sindh Province ◽  
Causal Fungus

Fusarium oxysporum f.sp. lycopersici (FOL) is a highly destructive fungal pathogen of tomato crop causing wilt disease which may reduce 10 to 90% yield. In Pakistan, tomato is widely grown in Sindh province, major territories are district Hyderabad, Tando Allahyar and Mirpurkhas. Thus, surveys of these territories were conducted to record intensity of the disease and confirm etiology. Furthermore, potential of different botanical pesticides and commercially available fungicides were tested to inhibit mycelial growth of the causal fungus. The experiment was laid down with complete randomized block design with three replications. The results showed that the disease was occurring in all locations with the range of 8-47 % incidence. F. oxysporum f.sp. lycopersici was predominantly isolated from the collected disease sample during survey and pathogenic nature of the fungus was tested on the tomato Golo variety through soil drenching method. The disease incidence of 30 and 42 % (72 % as total) was recorded in inoculated tomato plants at 20 and 40 DAI, respectively. Maximum (67 %) inhibition of the fungal growth was found by neem seed extracts at higher dose of 8 % concentration followed by 63 % with neem seeds and Eucalyptus at 6 and 8 %, respectively. Alternatively, the Nativo 75 WG fungicide was found most effective in reducing the redial mycelial growth of target fungus followed by Topsin-M at 1000 ppm where as Aliette and Melodedue fungicides were found least effective under in-vitro conditions.

scholarly journals Waktu Inkubasi pada Derajat Distilasi Kitosan Enzim dan Efektifitas Penghambatannya terhadap Penyakit Antraknosa

2017 ◽  
Vol 12 (6) ◽  
pp. 209
Author(s):  
Yadi Suryadi ◽  
Tri Puji Priyatno ◽  
I Made Samudra ◽  
Dwi Ningsih Susilowati ◽  
Hermawati Nurzulaika ◽  
...  
Keyword(s):  
Spore Germination ◽  
Burkholderia Cepacia ◽  
Fungal Growth ◽  
The Other ◽  
In Vitro Assays ◽  
Incubation Condition ◽  
Coating Agent ◽  
Optimal Incubation

The use of chitosan as a coating agent of harvested fruits is an alternative method in controlling anthracnose disease (Colletotrichum sp.). This study aimed to obtain an optimal enzymatic chitosan (EC) that hydrolyzed using chitinase from Burkholderia cepacia isolate E76. The optimal incubation condition to produce EC was 2 h with the yield of 3.52 ± 0.38 g. The degree of deacetylation (DD) chitosan and  EC was 66.91% and 80.91%, respectively. Based on in vitro assays, EC 2% was the most effective in inhibiting the growth of Colletotrichum sp. (94.22%)  than chitosan, while the highest inhibition for chitosan 3% was 55.26%. Moreover, the EC 2% showed the highest inhibition of spore germination (74.12%). The in vivo assay revealed that EC 2% showed the highest inhibition on the fungal growth (88.88%), compared to the other concentrations. On the other hand, the EC 2% and 3% gave similar results on inhibition of Colletotrichum sp.of chili (55.55%). 

scholarly journals Potential of antimicrobial volatile organic compounds to control Sclerotinia sclerotiorum in bean seeds

2011 ◽  
Vol 46 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Maurício Batista Fialho ◽  
Maria Heloisa Duarte de Moraes ◽  
Annelise Roberta Tremocoldi ◽  
Sérgio Florentino Pascholati
Keyword(s):  
Volatile Organic Compounds ◽  
Ethyl Acetate ◽  
Organic Compounds ◽  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
In Vitro Assays ◽  
Phytopathogenic Fungus ◽  
Volatile Organic ◽  
Ethyl Octanoate

The objective of this work was to evaluate the potential of an artificial mixture of volatile organic compounds (VOCs), produced by Saccharomyces cerevisiae, to control Sclerotinia sclerotiorum in vitro and in bean seeds. The phytopathogenic fungus was exposed, in polystyrene plates, to an artificial atmosphere containing a mixture of six VOCs formed by alcohols (ethanol, 3-methyl-1-butanol, 2-methyl-1-butanol and phenylethyl alcohol) and esters (ethyl acetate and ethyl octanoate), in the proportions found in the atmosphere naturally produced by yeast. Bean seeds artificially contamined with the pathogen were fumigated with the mixture of VOCs in sealed glass flasks for four and seven days. In the in vitro assays, the compounds 2-methyl-1-butanol and 3-methyl-1-butanol were the most active against S. sclerotiorum, completely inhibiting its mycelial growth at 0.8 µL mL-1, followed by the ethyl acetate, at 1.2 µL mL-1. Bean seeds fumigated with the VOCs at 3.5 µL mL-1 showed a 75% reduction in S. sclerotiorum incidence after four days of fumigation. The VOCs produced by S. cerevisiae have potential to control the pathogen in stored seeds.

Tulbaghia violacea L. I: In vitro antimicrobial properties towards plant pathogens

2006 ◽  
Vol 57 (5) ◽  
pp. 511 ◽  
Author(s):  
Leeto Nteso ◽  
Johan C. Pretorius
Keyword(s):  
Pseudomonas Syringae ◽  
Mycelial Growth ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Antimicrobial Properties ◽  
Diffusion Method ◽  
Mycosphaerella Pinodes ◽  
Soil Extracts

The antimicrobial properties of crude methanol extracts of above- and below-soil parts of Tulbaghia violacea were quantified by means of an agar diffusion method against 6 plant pathogenic bacteria and 7 fungi. The growth of 3 out of the 6 bacteria, Clavibacter michiganensis, Ralstonia solanacearum, and Xanthomonas campestris, was significantly inhibited by crude extracts of both below-soil and aerial parts of T. violacea, whereas the growth of Pseudomonas syringae, Erwinia carotovora, and Agrobacterium tumefaciens was unaffectedl. Compared with the standard fungicide, both the aerial and below-soil extracts of T. violacea significantly inhibited the mycelial growth of 6 of the 7 test fungi, Botrytis cinerea, Sclerotium rolfsii, Rhizoctonia solani, Mycosphaerella pinodes, Botryosphaeria dothidea, and P. ultimum, whereas only the below-soil extract inhibited the mycelial growth of Fusarium oxysporum significantly. The broad-spectrum antifungal activity shown by the crude T. violaceae extracts supplied a rationale for a further investigation into the in vivo activity of the extracts under glasshouse and field conditions.

scholarly journals Baseline Sensitivities of Fungal Pathogens of Fruit and Foliage of Citrus to Azoxystrobin, Pyraclostrobin, and Fenbuconazole

Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1186-1194 ◽  
Author(s):  
S. N. Mondal ◽  
Alka Bhatia ◽  
Turksen Shilts ◽  
L. W. Timmer
Keyword(s):  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Fungal Species ◽  
Brown Spot ◽  
Colletotrichum Acutatum ◽  
Fungicide Sensitivity ◽  
Fruit Drop ◽  
Coefficients Of Variation ◽  
Foliar Pathogens

The baseline sensitivities for mycelial growth of foliar fungal pathogens of citrus, Colletotrichum acutatum, Alternaria alternata, Elsinoe fawcettii, Diaporthe citri, and Mycosphaerella citri, the causal agents of postbloom fruit drop, brown spot of tangerine, citrus scab, melanose, and greasy spot, respectively, were determined in vitro for azoxystrobin, pyraclostrobin, and fenbuconazole. The effective dose to reduce growth by 50% (ED50 values) was determined for each pathogen-fungicide combination using five isolates from different citrus areas of Florida and eight fungicide concentrations. A discriminatory dose for each combination was selected near the ED50, and the range of sensitivity of 50 to 62 isolates of each fungal species was determined. The effect of salicylhydroxamic acid (SHAM) on the sensitivity of the five fungal species to azoxystrobin and pyraclostrobin was determined. Since mycelial growth of A. alternata was insensitive to azoxystrobin, the effect of that fungicide with and without SHAM on spore germination was assessed. The ED50 values for most fungal pathogens of citrus were relatively high compared with foliar pathogens of other tree crops. Values for azoxystrobin ranged from a low of 0.06 μg/ml with E. fawcettii to a high of >100 μg/ml with A. alternata. With pyraclostrobin, the values ranged from a low of 0.019 μg/ml with D. citri to a high of 0.87 μg/ml with A. alternata. With fenbuconazole, the lowest ED50 value was 0.21 μg/ml with M. citri and the highest was 1.01 μg/ml with C. acutatum, but A. alternata and D. citri were not tested. SHAM was inhibitory to all species and reduced growth of D. citri greatly. Inclusion of SHAM in the medium did not greatly affect the sensitivity of mycelial growth of these fungi to azoxystrobin or pyraclostrobin, nor did it affect the ED50 values for conidial germination of A. alternata. The coefficients of variation for the sensitivity of 50 to 62 isolates of each species to these fungi ranged from 7.3% with the pyraclostrobin-C. acutatum combination to a high of 55.0% with the fenbuconazole- M. citri combination. Discriminatory doses have been established for these pathogen- fungicide combinations that should be useful for detecting major shifts in fungicide sensitivity.

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.

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