scholarly journals Inactivation of Rhizoctonia solani in fertigation water using regenerative in situ electrochemical hypochlorination

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Serge Lévesque ◽  
Thomas Graham ◽  
Dorin Bejan ◽  
Jamie Lawson ◽  
Ping Zhang ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Plant Pathogens ◽  
Effective Means ◽  
Free Chlorine ◽  
Cell Contact ◽  
Pathogen Inactivation ◽  
Dimensionally Stable Anodes ◽  
Pathogen Control ◽  
Treatment Technologies

Abstract The capture and re-use of greenhouse fertigation water is an efficient use of fertilizer and limited water resources, although the practice is not without risk. Plant pathogens and chemical contaminants can build up over successive capture and re-use cycles; if not properly managed they can lead to reduced productivity or crop loss. There are numerous established and emerging water treatment technologies available to treat fertigation water. Electrochemical processes are emerging as effective means for controlling pathogens via in situ regenerative hypochlorination; a process that is demonstrated here to achieve pathogen control in fertigation solutions without leading to the accumulation of potentially phytotoxic free chlorine residuals associated with other chlorination processes. An electrochemical flow cell (EFC) outfitted with ruthenium dioxide (RuO2) dimensionally stable anodes (DSA) was characterized and evaluated for free chlorine production and Rhizoctonia solani inactivation in both irrigation and fertigation solutions. Pathogen inactivation was achieved at low current densities and short residence or cell contact times. Effluent free chlorine concentrations were significantly lower than commonly reported phytotoxic threshold values (approximately 2.5 mg/L) when fertilizer (containing ammonium) was present in the test solution; an effect attributable to reactions associated with breakpoint chlorination, including chloramine formation, as well as the presence of other oxidizable compounds in the fertilizer. Chloride concentrations were stable under the test conditions suggesting that the EFC was operating as a regenerative in situ electrochemical hypochlorination system. No significant changes to macronutrient concentrations were found following passage through the EFC.

scholarly journals Electrochemical detection of free-chlorine in Water samples facilitated by in-situ pH control using interdigitated microelectrodes

2020 ◽  
Vol 325 ◽  
pp. 128774 ◽  
Author(s):  
Ian Seymour ◽  
Benjamin O’Sullivan ◽  
Pierre Lovera ◽  
James F. Rohan ◽  
Alan O’Riordan
Keyword(s):  
Electrochemical Detection ◽  
Water Samples ◽  
Ph Control ◽  
Free Chlorine ◽  
Interdigitated Microelectrodes

Sensory aspects of drinking water in contact with epoxy lined copper pipe

2007 ◽  
Vol 55 (5) ◽  
pp. 161-168 ◽  
Author(s):  
T.H. Heim ◽  
A.M. Dietrich
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Organic Compounds ◽  
Sensory Analysis ◽  
Water Samples ◽  
Distribution System ◽  
Distribution Systems ◽  
Free Chlorine ◽  
Copper Pipe

Pipe relining via in situ epoxy lining is used to remediate corroded plumbing or distribution systems. This investigation examined the effects on odour, TOC, THM formation and disinfectant demand in water exposed to epoxy-lined copper pipes used for home plumbing. The study was conducted in accordance with the Utility Quick Test, a migration/leaching method for utilities to conduct sensory analysis of materials in contact with drinking water. The test was performed using water with no disinfectant and levels of chlorine and monochloramines representative of those found in the distribution system. Panelists repeatedly and consistently described a “plastic/adhesive/putty” odour in the water from the pipes. The odour intensity remained relatively constant for each of two subsequent flushes. Water samples stored in the epoxy-lined pipes showed a significant increase in the leaching of organic compounds (as TOC), and this TOC was demonstrated to react with free chlorine to form trichloromethane. Water stored in the pipes also showed a marked increase in disinfectant demand relative to the water stored in glass control flasks. A study conducted at a full scale installation at an apartment demonstrated that after installation and regular use, the epoxy lining did not yield detectable differences in water quality.

scholarly journals Mapping of UV-C dose and SARS-CoV-2 viral inactivation across N95 respirators during decontamination

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alisha Geldert ◽  
Alison Su ◽  
Allison W. Roberts ◽  
Guillaume Golovkine ◽  
Samantha M. Grist ◽  
...  
Keyword(s):  
Optical Simulation ◽  
Pathogen Inactivation ◽  
Viral Inactivation ◽  
Flexible Form ◽  
Measurement Tools ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Dose Difference

AbstractDuring public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. Pathogen photoinactivation efficacy depends critically on UV-C dose, which is distance- and angle-dependent and thus varies substantially across N95 surfaces within a decontamination system. Due to nonuniform and system-dependent UV-C dose distributions, characterizing UV-C dose and resulting pathogen inactivation with sufficient spatial resolution on-N95 is key to designing and validating UV-C decontamination protocols. However, robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient (1) small, flexible form factor, and (2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of “on-N95” UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces in the chamber, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we integrate optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific on-N95 locations, establishing a versatile approach to characterize UV-C photoinactivation of pathogens contaminating complex substrates such as N95s.

scholarly journals In situ Impact of the Antagonistic Fungal Strain, Trichoderma gamsii T30 on the Plant Pathogenic Fungus, Rhizoctonia solani in Soil

2019 ◽  
Vol 68 (2) ◽  
pp. 211-216
Author(s):  
MUHAMMAD ANEES ◽  
MUHAMMAD ABID ◽  
SOBIA CHOHAN ◽  
MUHAMMAD JAMIL ◽  
NADEEM AHMED ◽  
...  
Keyword(s):  
Population Density ◽  
Rhizoctonia Solani ◽  
Pathogenic Fungus ◽  
Suppressive Effect ◽  
Fungal Strain ◽  
Soil Microbiome ◽  
Target Dna ◽  
Wide Range ◽  
First Time

Rhizoctonia solani is a soil-borne fungus causing a wide range of plants diseases. Trichoderma gamsii strain T30 has previously been reported as antagonistic against R. solani. Although there are a few studies about the influence of Trichoderma strains on the R. solani densityin a pathosystem in the presence of plant hosts, this report for the first time comprehensively describes in situ effects of a T. gamsii strain on the population density of R. solani in the soil microcosmic conditions. The population dynamics of R. solani were followed in the autoclaved and non-autoclaved soils in artificially prepared microcosms up to day 25 after co-inoculation with T. gamsii in the variable ratios (R1/T1; R1/T0.1; R1/T0.01 of R. solani/T. gamsii). The population density of R. solani was evaluated by qPCR. In the autoclaved soil, target DNA copies of R. solani increased in the control samples from 1 × 105 to 6.5 × 106. At R1/T0.01, the number of target DNA copies were not significantly changed until day 11; however, it decreased by around five times at day 25. At R1/T0.1 and R1/T1, the number of DNA copies was reduced to 2.1 × 106 and 7.6 × 105 at day 11, respectively and the reduction was as much as 17 times at day 25. In the non-autoclaved soil, the number of the fungal cells decreased at day 25 whether inoculated or not with Trichoderma indicating a general suppression by the soil microbiome. In brief, T. gamsii significantly inhibited the growth of R. solani in the soil in situ and there was a general suppressive effect of the natural microbiome.

scholarly journals Effect of Fungal Metabolites and Amendments on Mycelial Growth of Rhizoctonia Solani

2010 ◽  
Vol 50 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Keyword(s):  
Rhizoctonia Solani ◽  
Culture Filtrate ◽  
Mycelial Growth ◽  
Plant Pathogens ◽  
Organic Amendment ◽  
Test Organism ◽  
Suppressive Effect ◽  
Fungal Metabolites ◽  
Castor Cake

Effect of Fungal Metabolites and Amendments on Mycelial Growth ofRhizoctonia SolaniA shift towards organic farming suggests amalgamation of organic resources against soil borne plant pathogens. The influence of metabolites of most ubiquitousAspergillusspp., organic amendment extracts and their combined effect withTrichoderma virenswere evaluatedin vitroagainstRhizoctonia solani.The minimum (36.1 mm) growth was attained byR. solaniin co-culture withA. niger.The maximum (42.3 mm) inhibition of mycelial growth of the test organism was observed with culture filtrate ofA. ochraceousfollowed byA. niger, A. fumigatus, A. flavusandA. terreus.Among organic amendment extractants, castor cake exhibited an additive effect on the growth ofT. virens, however, the maximum (41.8 mm) suppressive effect onR. solaniwas observed with vermicompost. With the advance in time, the effect of organic amendment extracts increased markedly. Inhibition potential of culture filtrate mixturte ofA. niger+T. virensandA. ochraceous+T. virensagainstR. solaniwas significantly higher in comparison to the other combinations.

scholarly journals When time really is money: in situ quantification of the strobilurin resistance mutation G143A in the wheat pathogen Blumeria graminis f. sp. tritici

2020 ◽  
Author(s):  
Kejal N Dodhia ◽  
Belinda A Cox ◽  
Richard P Oliver ◽  
Francisco J Lopez-Ruiz
Keyword(s):  
Fungicide Resistance ◽  
Plant Pathogens ◽  
Resistance Mutation ◽  
Digital Pcr ◽  
Blumeria Graminis ◽  
Diagnostic Methods ◽  
Sample Collection ◽  
Specific Pcr ◽  
Field Samples

AbstractBackgroundThere has been an inexorable increase in the incidence of fungicide resistance in plant pathogens in recent years. Control of diseases and the management of resistance would be greatly aided by rapid diagnostic methods. Quantitative allele specific PCR (ASqPCR) is an ideal technique for the analysis of fungicide resistance in the field as it can both detect and quantify the frequency of mutations associated with fungicide resistance. We have applied this technique to the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), an obligate biotrophic fungus that causes wheat powdery mildew and is responsible for up to 25% yield loss annually. In Australia, strobilurin resistant Bgt was first discovered in samples from Tasmania and Victoria in 2016. Molecular analysis revealed a nucleotide transversion in the cytochrome bc1 enzyme (cytb) complex, resulting in a substitution of alanine for glycine at position 143 (G143A) in Cytb.ResultsWe have developed an in-field ASqPCR assay that can quantify both the resistant (A143) and sensitive (G143) cytb alleles down to 1.67% in host and Bgt DNA mixtures within 90 min of sample collection. The in situ analysis of field samples collected during a survey in Tasmania revealed A143 frequencies ranging between 9-100%. We validated the analysis with a newly developed laboratory based digital PCR assay and found no significant differences between the two methods.ConclusionWe have successfully developed an in-field quantification method, for a QoI resistant allele, by pairing an ASqPCR assay on a lightweight qPCR instrument with a quick DNA extraction method. The deployment of this type of methodologies in the field can contribute to the effective in-season management of fungicide resistance.

STUDIES ON THE GROWTH IN SOIL AND THE PARASITIC ACTION OF CERTAIN RHIZOCTONIA SOLANI ISOLATES FROM WHEAT

1942 ◽  
Vol 20c (3) ◽  
pp. 174-185 ◽  
Author(s):  
I. D. Blair
Keyword(s):  
Plant Growth ◽  
Rhizoctonia Solani ◽  
Soil Depth ◽  
Effective Means ◽  
Growth Period ◽  
Severe Form ◽  
Disease Rating ◽  
Pathogenicity Tests ◽  
Unsterilized Soil ◽  
The One

An adaptation of the Rossi and Cholodny glass slide technique was found to be an effective means of measuring the growth of Rhizoctonia Solani in soil. After a 6 day and a 12 day period, the extent of growth of 11 isolates of this fungus was, for each growth period, less in a vertical than in a radial direction. Certain isolates grew faster than others. A comparison of the radial growth of a faster and of a slower growing isolate at soil depth of 2, 4, and 6 in. showed that the extent of growth decreased with depth, being significantly greater for both isolates at the 2 in. than at the 6 in. level.In pathogenicity tests on wheat with 10 of these isolates, the disease rating for each isolate was greater in natural than in steam sterilized soil, and in soil with a proportion of inoculum to soil of one to six than of one to three. The addition of cellulosic organic material, grass- or straw-meal, to unsterilized soil was effective in reducing the parasitic action of all isolates. Two distinct types of injury were observed: the one, a severe form of root injury, resulting in reduced plant growth; the other, a girdling of the coleoptile or lower stem tissue, usually unaccompanied by adverse effects on plant growth. The first type was produced by two slow growing isolates of English origin, the second by faster growing isolates of Canadian origin. On the basis of these differences, it is suggested that the root injuring isolates be regarded as a variety of R. Solani Kühn.

In-Situ Treatment Technologies

2002 ◽  
pp. 183-216
Author(s):  
C. H. Ward ◽  
J. B. Hughes ◽  
G. A. Pope ◽  
M. Delshad ◽  
V. Dwaranath ◽  
...  
Keyword(s):  
Treatment Technologies

scholarly journals Biological activity of 7beta-acetoxywithanolide D isolated from Acnistus arborescens

2018 ◽  
Vol 39 (6) ◽  
pp. 2835
Author(s):  
Joze Aparecida Marciano Corrêa ◽  
Diana Fortkamp ◽  
Camila Furtunato da Silva ◽  
Flávio Rocha ◽  
Luiz Humberto Gomes ◽  
...  
Keyword(s):  
Biological Activity ◽  
Secondary Metabolites ◽  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Plant Secondary Metabolites ◽  
Alternative Methods ◽  
Development Of Resistance ◽  
Pathogen Control ◽  
Solanaceae Family ◽  
Promising Source

Many oomycete species are plant pathogens and are responsible for causing significant losses in agriculture. Currently, plant pathogen control is carried out by chemical, biological and physical methods. However, due to the development of resistance to these methods by some pathogens, it is imperative that alternative methods are developed. Brazilian biodiversity is well-known for its species richness and is considered a promising source of natural products. Among the vascular plants, the family Solanaceae A. Juss. (Solanaceae) is considered one of the largest, with distributions across all tropical and temperate regions of the world. The Solanaceae family presents a high diversity of species of economic importance as sources of food, medicinal and ornamental properties. Plants of this family are sources of secondary metabolites of various chemical classes that possess potential diverse applications. Therefore, chemical and biological investigations of these compounds are extremely important as they present alternatives for their potential use in the control of plant pathogens. Here, we report for the first time, the biological activity of 7beta-acetoxywithanolide D, a compound isolated from Acnistus arborescens, against the oomycete Phytophthora cinnamomi. With these results, we emphasize the importance of such studies on plant secondary metabolites, which may present coadjuvant options in the control of plant pathogens.

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