scholarly journals Effects of Chitin and Chitosan on the Incidence and Severity of Fusarium Yellows of Celery

Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 322-328 ◽  
Author(s):  
Ashley A. Bell ◽  
Judith C. Hubbard ◽  
Li Liu ◽  
R. Michael Davis ◽  
Krishna V. Subbarao
Keyword(s):  
Fusarium Oxysporum ◽  
Disease Severity ◽  
Field Experiments ◽  
Disease Incidence ◽  
Soil Microflora ◽  
Biocontrol Agents ◽  
Standard Soil ◽  
History Of ◽  
Chitin And Chitosan ◽  
Soil Dilution

The effects of chitin and chitosan on disease incidence and severity of Fusarium yellows of celery and on populations of Fusarium oxysporum were investigated between 1994 and 1996. Field experiments were conducted at two locations with a history of severe Fusarium yellows. Disease incidence and severity were significantly reduced by pre-plant chitin amendments to soil. Chitosan applied as a root dip alone did not reduce disease incidence but significantly (P < 0.05) reduced disease severity when used with a tolerant celery cultivar. Standard soil dilution methods were used to enumerate populations of soil microflora. Chitin increased bacterial and actinomycete populations in soil in 2 of the 3 years of study. The effects of potential biocontrol agents recovered from chitin-treated plots in 1995 were studied in 1996; enriching the transplant medium with isolates of bacteria and actinomycetes 4 weeks and 1 week prior to transplanting did not alter the established equilibrium in the field, and no biocontrol effect was observed. Chitin amendments to soil or chitosan treatment of transplants did not reduce soil populations of F. oxysporum. Whether these treatments affected the F. oxysporum f. sp. apii subpopulation within the F. oxysporum population could not be determined.

scholarly journals Role of Biocontrol Agents in Management of Corm Rot of Saffron Caused by Fusarium oxysporum

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1398
Author(s):  
Vishal Gupta ◽  
Krishna Kumar ◽  
Kausar Fatima ◽  
Vijay Kumar Razdan ◽  
Bhagwati Charan Sharma ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Growth Promotion ◽  
Disease Incidence ◽  
Biocontrol Agents ◽  
Crocus Sativus ◽  
First Year ◽  
Dual Culture ◽  
Maximum Reduction

Saffron (Crocus sativus L.) is considered as one of the most expensive spices. Fusarium corm rot of saffron, caused by Fusarium oxysporum, is known to cause severe yield losses worldwide. In the present study, efficacy of biocontrol agents (Trichoderma asperellum, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas putida, Bacillus stratosphericus, Bacillus pumilus, and Bacillus subtilis) along with a chemical fungicide, carbendazim, was evaluated for managing the corm rot of saffron. Under in vitro conditions, using dual culture and poison food techniques on potato dextrose agar, T. asperellum and carbendazim significantly reduced the mycelial growth of the pathogen F. oxysporum, with the inhibition of 62.76 and 60.27%, respectively, compared with control. Under field conditions, dipping of saffron corms in carbendazim and T. asperellum exhibited maximum reduction of 82.77 and 77.84%, respectively, in the disease incidence, during the first year of experiment. However, during the second year, maximum reduction in the incidence of corm rot (68.63%) was recorded with the T. asperellum. Moreover, the population density of F. oxysporum was also significantly reduced by 60 and 80.19% while using T. asperellum after 75 and 260 days of sowing of saffron corms, compared to its population before planting of corms. In case of growth promotion traits, such as sprouting and flowering, biocontrol treatments reduced the number of days (average) of sprouting and flower emergence after sowing, compared to control.

Resistance of standing milkvetch (Astragalus adsurgens) varieties to Embellisia astragali

2012 ◽  
Vol 63 (4) ◽  
pp. 351 ◽  
Author(s):  
B. H. Yu ◽  
Z. B. Nan ◽  
Y. Z. Li ◽  
H. L. Lin
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Agronomic Traits ◽  
Disease Incidence ◽  
Dry Weight ◽  
Severity Index ◽  
Field Conditions ◽  
Disease Severity Index ◽  
Greenhouse Experiments ◽  
Astragalus Adsurgens

Yellow stunt and root rot caused by Embellisia astragali are major factors contributing to declining yields of standing milkvetch (Astragalus adsurgens). The resistance of ten varieties of standing milkvetch to E. astragali was evaluated under laboratory, greenhouse, and field conditions. Seed germination/emergence, shoot and root length, plant dry weight, disease incidence, mortality, and disease severity index were monitored. The results show that Shanxi and Zhongsha No. 1 varieties had the best agronomic traits and lowest levels of disease in all experiments, while the varieties Neimeng and Ningxia had the highest susceptibility to disease. Germination/emergence differed significantly (P < 0.05) between varieties after inoculation, and compared with the control, germination/emergence of inoculated treatments of nine varieties decreased on average by 1.5% in laboratory experiments and by 4.1% in greenhouse experiments at 15 days after inoculation. Inoculation reduced shoot length by an average of 24.4% and 41.5% (P < 0.05) in laboratory and greenhouse experiments, respectively, in six of ten varieties. All varieties showed significantly (P < 0.05) lower plant dry weight following inoculation, with reductions ranging from 0.3 to 0.6 mg in the laboratory and from 82.6 to 149.4 mg in the greenhouse. Resistance to the pathogen was evaluated on the basis of disease incidence, a disease severity index (DSI), and mortality; varieties showing different resistance were grouped using cluster analysis. There were significant correlations between the results of laboratory and greenhouse experiments (r = 0.79; P < 0.01) and between greenhouse and field experiments (r = 0.83; P < 0.01) across all varieties. Multiple regression analysis between laboratory/greenhouse and field experiments on DSI suggested that screening in the laboratory/greenhouse could be an alternative method of rapidly estimating DSI under field conditions.

scholarly journals Development of next-generation formulation against Fusarium oxysporum and unraveling bioactive antifungal metabolites of biocontrol agents

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monika Jangir ◽  
Shilpi Sharma ◽  
Satyawati Sharma
Keyword(s):  
Fusarium Oxysporum ◽  
Volatile Compounds ◽  
Disease Incidence ◽  
Hydrolytic Enzymes ◽  
Biocontrol Agents ◽  
Bioactive Metabolites ◽  
Next Generation ◽  
Talcum Powder ◽  
Antifungal Metabolites ◽  
Culture Filtrates

AbstractBiocontrol agents serve as a sustainable means of controlling wilt caused by the widespread plant pathogen, Fusarium oxysporum f. sp. lycopersici. The present study aimed to develop water dispersible granules (WDG) using response surface methodology (RSM) for Bacillus subtilis MTCC 2274 and Trichoderma harzianum MTCC 3928, and to compare their antifungal efficacy with other formulations. Further, characterization of the bioactive metabolites responsible for biocontrol was performed. A new microbial formulation, WDG, was developed in the present study with talcum powder (substrate), alginic acid (dispersing agent) and acacia gum (wetting agent) (suspensibility 82.23%; wetting time 2.5 min; dispersion time 10.08 min) that fulfilled the guidelines of Collaborative International Pesticides Analytical Council (CIPAC). In planta study demonstrated that WDG of B. subtilis showed maximum reduction in disease incidence (48%) followed by talc formulation of B. subtilis (44%) and WDG of T. harzianum (42%) with profound effect on plant growth promotion. B. subtilis and T. harzianum demonstrated protease (929 and 846 U ml−1 min−1), chitinase (33.69 and 154 U ml−1 min−1), and β-1,3-glucanase (12.69 and 21.47 U ml−1 min−1) activities. Culture filtrates of B. subtilis and T. harzianum exhibited significant inhibition against mycelial growth of pathogen. The compounds present in the culture filtrates were identified with GC–MS as fatty acids, alkanes, phenols, benzene, pyran derivatives etc. The major non-volatile compounds in bioactive antifungal fraction were identified as derivatives of morpholine and piperdine for T. harzianum and B. subtilis, respectively. The findings propose a multivariate biocontrol mechanism against phytopathogen by production of hydrolytic enzymes, volatile and non-volatile compounds, together with development of an efficient next-generation formulation.

scholarly journals Effect of Traditional Agronomic Practices on White Rust of Rapeseed – Mustard under Organic Farming System in Manipur

2017 ◽  
Vol 5 (3) ◽  
pp. 354-358
Author(s):  
Yengkhom Premlata Devi
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Plant Density ◽  
Disease Incidence ◽  
Farmyard Manure ◽  
Farming System ◽  
Severe Form ◽  
Rust Disease ◽  
White Rust ◽  
Agronomic Practices

Rapeseed – mustard is one of the most important cruciferous oilseed crops basically raise for oils and vegetables to meet domestic consumption of marginal farmers during rabi season in Manipur. Field experiments were conducted under organic condition for two consecutive years ( 2014 & 2015) during rabi seasons at Kakching. Weekly surveys detected white rust of rapeseed –mustard on the four varieties used. Amendments of agronomic practices including sowing dates, intercropping and plant density besides addition of soil with FYM (Farmyard Manure) were found effective on fungal disease of the crop. The disease parameters were monitored through disease incidence (DI) and disease severity (DS) assessment technique. The least disease severity (9.57%) was found in plant density followed by date of sowing (11.06%) and intercropping (12.29%). White rust caused by Albugo candida attacked the crop from mild to severe form and the effect of agronomic practices applied were significant in controlling the white rust disease of the crop.

scholarly journals EFFECT OF BOTANICALS FOR MANAGEMENT OF LEAF BLAST AND ENHANCING YIELD TRAITS IN RICE

2018 ◽  
pp. 17-21
Author(s):  
SANDEEP PANDEY
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Field Experiments ◽  
Disease Incidence ◽  
Grain Weight ◽  
Panicle Length ◽  
Leaf Blast ◽  
Yield Attributes ◽  
Pooled Data ◽  
Cent Disease

Field experiments were undertaken during kharif 2012 and 2013 under irrigated ecosystem to evaluate the efficacy of botanicals along with standard fungicides for assessing per cent disease incidence, plant height, number of tiller per plant, number of spikelet per panicle, panicle length, 100-grain weight and grain yield against blast of rice. Pooled data of two years suggest that neem based commercial biopesticides with azadiractin as active ingredients were found effective in reducing disease severity and improving the yield attribute of the crop and proves promising products when compared to standard fungicides. Among the botanicals the spraying of Achook, Neem Azal T/S, Neem gold and Tricure shows significant reduction in disease severity, along with improving yield attributes, increasing the 100-grain weight and grain yield.

Sensitivity of Fusarium oxysporum f. sp. niveum to Prothioconazole and Pydiflumetofen In Vitro and Efficacy for Fusarium Wilt Management in Watermelon

2020 ◽  
Vol 21 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Nathan F. Miller ◽  
Jeffrey R. Standish ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
North Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Field Experiments ◽  
Foliar Application ◽  
Citrullus Lanatus ◽  
Disease Incidence ◽  
Application Rate ◽  
Current Evidence ◽  
Progress Curve

Field experiments were conducted in 2015 and 2016 to determine the effects of drench or drench-plus-foliar applications of prothioconazole and pydiflumetofen on Fusarium wilt (caused by Fusarium oxysporum f. sp. niveum; FON) of watermelon (Citrullus lanatus var. lanatus). In both years, all fungicide treatments reduced final disease incidence, final severity, and area under the disease progress curve, regardless of application rate or method. Yield data were collected in 2016, and both number and weight of marketable fruit were greatest in plots treated with pydiflumetofen as a drench-plus-foliar application at either application rate. Additional experiments were conducted to characterize sensitivity distributions of 48 isolates of FON from North Carolina to prothioconazole and pydiflumetofen. Mean prothioconazole EC50 values ranged from 0.10 to 0.55 µg/ml, and mean pydiflumetofen EC50 values ranged from 0.34 to 1.88 µg/ml. The results presented here validate pydiflumetofen as an effective management option for Fusarium wilt of watermelon, confirm previously observed efficacy of prothioconazole, and provide current evidence of pathogen sensitivity to these fungicides in North Carolina.

scholarly journals Efficacy of Trichoderma Fortified Organic Amendments on Fusarium Wilt Suppression, Growth and Yield of Eggplant

2021 ◽  
pp. 1-16
Author(s):  
V. Govardhan Rao ◽  
D. N. Dhutraj ◽  
K. D. Navgire ◽  
K. T. Apet
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Field Experiments ◽  
Biological Control Agent ◽  
Disease Incidence ◽  
Organic Amendments ◽  
Growth And Yield ◽  
Seedling Mortality ◽  
Soil Application ◽  
Pot Culture

Trichoderma harzianum is commonly used as effective biological control agent against phytopathogens especially the soil-borne fungi while some isolates are able to ameliorate plant growth. In the present study, Trichoderma fortified with different organic amendments were evaluated to reduce the pre-emergence and post-emergence seedling mortality, diseases of stem and root of eggplant caused by Fusarium oxysporum f. sp. melongenae, a soil-borne fungal pathogen. Two experiments were set up, one at pot culture and second in the field under natural epiphytotic conditions. Among the nine Trichoderm harzianum fortified amendments tested, neem seed cake recorded significant and superior effect as pre-sowing soil application against Fusarium wilt with respect to seed germination (92.33%), pre-emergence seed rot (7.66%) and post-emergence seedling mortality (15.33%) in pot culture. However, cotton cake recorded least efficacy in all respect. Similar trend observed in wilt incidence under field experiments during autumn 2018 (17.47%) and 2019 (18.60%) with T. harzianum fortified neem cake soil application against Fusarium wilt with mean inhibition of disease incidence (58.43%) and also observed excellent enhancement of mean yield (54.63%). It is observed that organic amendment at higher concentrations further increase the microbial populations and stimulate the microbial activity in soil against Fusarium oxysporum resulted to decrease the pathogen populations. Moreover, yield and yield related attributes increased remarkably due to fortified amendments providing adequate nutrient reservoir to the bioagents thereby enhancing its survival in a hostile environment.

Epidemiological studies on the anthracnose diseases of Stylosanthes spp. caused by Colletotrichum gloeosporioides in North Queensland and pathogenic specialization within the natural fungal populations

1987 ◽  
Vol 38 (6) ◽  
pp. 1019 ◽  
Author(s):  
RD Davis ◽  
JAG Irwin ◽  
DF Cameron ◽  
RK Shepherd
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Disease Incidence ◽  
Environmental Parameters ◽  
Epidemiological Studies ◽  
Field Resistance ◽  
Natural Occurrence ◽  
Fungal Population ◽  
Fungal Populations ◽  
Weather Parameters

Field experiments were conducted during three wet seasons (1982-84) on two sites in north Queensland to examine the natural occurrence of anthracnose caused by Collectotrichum gloeosporioides on six Stylosanthes spp. The disease incidence varied from moderate to high in a number of accessions, while others showed good field resistance for the duration of the experiment. Anthracnose severity was similar at both sites, although total rainfall each season was c. four times higher at one site than at the other. In some cases disease severity was higher at the drier site. It was difficult to determine a relationship between the environmental parameters measured (rainfall, temperature and relative humidity) and disease incidence and severity. Disease severity patterns varied between accessions at the same site, indicating a response to a factor or factors not associated with the measured weather parameters. There were seven pathogenicity groups, based on host specificities in glasshouse studies, identified within the Type A fungal population and a further seven groups within the Type B population. This indicates an increase in the number of fungal groups reported in Australia, and suggests that a stepwise increase in specificity may be occurring within the fungal population.

scholarly journals Mycelium Dispersion from Fusarium oxysporum f. sp. dianthi Elicits a Reduction of Wilt Severity and Influences Phenolic Profiles of Carnation (Dianthus caryophyllus L.) Roots

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1447
Author(s):  
Janneth Santos-Rodríguez ◽  
Ericsson Coy-Barrera ◽  
Harold Duban Ardila
Keyword(s):  
Fusarium Oxysporum ◽  
Disease Severity ◽  
Control Strategies ◽  
Disease Incidence ◽  
Dianthus Caryophyllus ◽  
Environmental Cost ◽  
Defensive Responses ◽  
Biotic Elicitor ◽  
Phenolic Profiles

The fungal pathogen Fusarium oxysporum f. sp. dianthi (Fod) is the causal agent of the vascular wilt of carnation (Dianthus caryophyllus L.) and the most prevalent pathogen in the areas where this flower is grown. For this reason, the development of new control strategies against Fod in carnation has been continuously encouraged, in particular those based on the implementation of plant resistance inducers that can trigger defensive responses to reduce the disease incidence, even at lower economical and environmental cost. In the present study, the effect of the soil supplementation of a biotic elicitor (i.e., ultrasound-assisted dispersion obtained from Fod mycelium) on disease severity and phenolic-based profiles of roots over two carnation cultivars was evaluated. Results suggest that the tested biotic elicitor, namely, eFod, substantially reduced the progress of vascular wilting in a susceptible cultivar (i.e., ‘Mizuki’) after two independent in vivo tests. The LC-MS-derived semi-quantitative levels of phenolic compounds in roots were also affected by eFod, since particular anthranilate derivatives, conjugated benzoic acids, and glycosylated flavonols were upregulated by elicitation after 144 and 240 h post eFod addition. Our findings indicate that the soil-applied eFod has an effect as a resistance inducer, promoting a disease severity reduction and accumulation of particular phenolic-like compounds.

Cryogels as a solution to the issues of environmental management and trunk pipeline operation in Arctic

2020 ◽  
Vol 10 (2) ◽  
pp. 173-185
Author(s):  
Lyubov K. Altunina ◽  
◽  
Vladimir P. Burkov ◽  
Petr V. Burkov ◽  
Vitaly Y. Dudnikov ◽  
...  
Keyword(s):  
Composite Materials ◽  
Field Experiments ◽  
Oil And Gas ◽  
Soil Layer ◽  
Soil Microflora ◽  
Russian Arctic ◽  
Thaw Cycle ◽  
Trunk Pipeline ◽  
Geological Conditions ◽  
Spatial Lattice

In the Russian Arctic, a soil cryostructuring technique (i.e. strengthening of soil horizons with cryogel-based composite materials with no excavation of unstable soils required) seems to be showing promise. Experiments have proven that mechanical and thermal insulation properties attributed to cryogels make them appropriate for use in strengthening and thermally insulating the soil, while their structure makes it possible to form a stable vegetation cover. Field experiments have confirmed that cryostructuring efficiently strengthens the soil layer with cryogels stimulating soil microflora. An experience of using cryotropic compositions in the oil and gas sector was described. Notably, cryogels can be used to strengthen unstable soil foundations of trunk pipelines, as well as to bind soil (e.g. on slopes). In addition, cryogels are advised for use in engineering protection to prevent the uneven settlement of a trench base and its creep: thus, cryogels are pumped into the soil of the trench bottom base to create a support system representing a spatial lattice. After the first freeze and thaw cycle, cryotropic material is formed and then increases its strength and elasticity with each new cycle. More broadly, opportunities have been considered regarding cryogels used in various engineering and geological conditions, while taking into account the outcomes of landscape and territorial analysis. It was concluded that cryogel-based composite materials are a promising innovative scientific field expanding technological capabilities for developing and using spaces and resources in the Russian Arctic.

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