scholarly journals Potential for Integrated Control of Sclerotinia sclerotiorum in Glasshouse Lettuce Using Coniothyrium minitans and Reduced Fungicide Application

2001 ◽  
Vol 91 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Simon P. Budge ◽  
John M. Whipps
Keyword(s):  
Disease Control ◽  
Sclerotinia Sclerotiorum ◽  
Integrated Control ◽  
Agar Plate ◽  
Solid Substrate ◽  
Infested Soil ◽  
Single Application ◽  
Coniothyrium Minitans ◽  
Highly Sensitive

All pesticides used in United Kingdom glasshouse lettuce production (six fungicides, four insecticides, and one herbicide) were evaluated for their effects on Coniothyrium minitans mycelial growth and spore germination in vitro agar plate tests. Only the fungicides had a significant effect with all three strains of C. minitans tested, being highly sensitive to iprodione (50% effective concentration [EC50] 7 to 18 μg a.i. ml-1), moderately sensitive to thiram (EC50 52 to 106 μg a.i. ml-1), but less sensitive to the remaining fungicides (EC50 over 200 μg a.i. ml-1). Subsequently, all pesticides were assessed for their effect on the ability of C. minitans applied as a solid substrate inoculum to infect sclerotia of Sclerotinia sclerotiorum in soil tray tests. Despite weekly applications of pesticides at twice their recommended concentrations, C. minitans survived in the soil and infected sclerotia equally in all pesticide-treated and untreated control soil trays. This demonstrated the importance of assessing pesticide compatibility in environmentally relevant tests. Based on these results, solid substrate inoculum of a standard and an iprodione-tolerant strain of C. minitans were applied individually to S. sclerotiorum-infested soil in a glasshouse before planting lettuce crops. The effect of a single spray application of iprodione on disease control in the C. minitans treatments was assessed. Disease caused by S. sclerotiorum was significantly reduced by C. minitans and was enhanced by a single application of iprodione, regardless of whether the biocontrol agent was iprodione-tolerant. In a second experiment, disease control achieved by a combination of C. minitans and a single application of iprodione was shown to be equivalent to that of prophylactic sprays with iprodione every 2 weeks. The fungicide did not affect the ability of C. minitans to spread into plots where only the fungicide was applied and to infect sclerotia. These results indicate that integrated control of S. sclerotiorum with soil applications of C. minitans and reduced foliar iprodione applications was feasible, did not require a fungicide tolerant isolate, and that suppression of Sclerotinia disease by C. minitans under existing chemical control regimes has credence.

scholarly journals Co-operative action by endo- and exo-β-(1→3)-glucanases from parasitic fungi in the degradation of cell-wall glucans of Sclerotinia sclerotiorum (Lib.) de Bary

1974 ◽  
Vol 140 (1) ◽  
pp. 47-55 ◽  
Author(s):  
David Jones ◽  
Alex. H. Gordon ◽  
John S. D. Bacon
Keyword(s):  
Cell Wall ◽  
Sclerotinia Sclerotiorum ◽  
Culture Filtrate ◽  
Cell Walls ◽  
Trichoderma Viride ◽  
Major Constituent ◽  
Coniothyrium Minitans ◽  
Parasitic Fungi ◽  
Complete Breakdown

1. Two fungi, Coniothyrium minitans Campbell and Trichoderma viride Pers. ex Fr., were grown on autoclaved crushed sclerotia of the species Sclerotinia sclerotiorum, which they parasitize. 2. in vitro the crude culture filtrates would lyse walls isolated from hyphal cells or the inner pseudoparenchymatous cells of the sclerotia, in which a branched β-(1→3)-β-(1→6)-glucan, sclerotan, is a major constituent. 3. Chromatographic fractionation of the enzymes in each culture filtrate revealed the presence of several laminarinases, the most active being an exo-β-(1→3)-glucanase, known from previous studies to attack sclerotan. Acting alone this brought about a limited degradation of the glucan, but the addition of fractions containing an endo-β-(1→3)-glucanase led to almost complete breakdown. A similar synergism between the two enzymes was found in their lytic action on cell walls. 4. When acting alone the endo-β-(1→3)-glucanase had a restricted action, the products including a trisaccharide, tentatively identified as 62-β-glucosyl-laminaribiose. 5. These results are discussed in relation to the structure of the cell walls and of their glucan constituents.

scholarly journals Variability in Sensitivity to Metalaxyl in vitro, Pathogenicity, and Control of Pythium spp. on Sugar Beet

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 896-899 ◽  
Author(s):  
J. R. Brantner ◽  
Carol E. Windels
Keyword(s):  
Sugar Beet ◽  
Disease Control ◽  
Seed Treatment ◽  
Linear Growth ◽  
Pythium Ultimum ◽  
Infested Soil ◽  
Pathogenicity Tests ◽  
And Control ◽  
Treatment Sensitivity

Pythium ultimum var. sporangiiferum (76 isolates) and P. aphanidermatum (21 isolates) cultured from diseased sugar beet seedlings in Minnesota and North Dakota were tested for sensitivity to metalaxyl, pathogenicity on sugar beet, and disease control by metalaxyl seed treatment. Sensitivity to metalaxyl (effective concentration causing 50% growth inhibition [EC50]) was determined by linear growth on corn meal agar amended with 0, 0.01, 0.1, 1, 10, and 100 μg a.i. metalaxyl ml-1 after 48 h in the dark at 21 ± 1°C. Variation among isolates was significant (P = 0.05) within and between species, and EC50 values averaged 0.16 (range: 0.05 to 1.30 μg ml-1) for P. ultimum var. sporangiiferum and 2.06 (range: 1.19 to 3.12 μg ml-1) for P. aphanidermatum. In pathogenicity tests on sugar beet, most isolates of P. ultimum var. sporangiiferum (72 of 76) and all of P. aphanidermatum significantly (P = 0.05) decreased final stands compared to the noninoculated control. There was no correlation between aggressiveness in the absence of metalaxyl and in vitro sensitivity to metalaxyl. When Pythium-infested soil was planted with seed treated with metalaxyl at the standard (0.625 g a.i. kg-1) or half rate, some isolates that were least sensitive to metalaxyl in vitro resulted in a significant (P = 0.05) reduction in disease control. These results may explain, at least in part, why producers do not attain expected stands when they plant metalaxyl-treated sugar beet seed.

scholarly journals Coniothyrium minitans survival in soil and ability to infect sclerotia of Sclerotinia sclerotiorum

2011 ◽  
Vol 64 ◽  
pp. 168-174 ◽  
Author(s):  
E.E. Jones ◽  
A. Stewart
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Solid Substrate ◽  
Spore Suspension ◽  
Hygromycin B ◽  
Wild Type ◽  
Coniothyrium Minitans ◽  
Soil Population ◽  
Unambiguous Detection ◽  
Amended Soil

Survival of the sclerotial parasite Coniothyrium minitans in soil when applied as spore suspension or colonised solid substrate (maizemealperlite) inocula and ability to infect Sclerotinia sclerotiorum sclerotia incorporated into the soil after different times was assessed over 6 months Unambiguous detection of the C minitans isolate from the indigenous C minitans soil population was achieved using a hygromycin B resistant transformant (T3) which was similar in behaviour to the wild type LU112 Coniothyrium minitans was recovered from soil by dilution plating at all assessment times with higher recovery from spore suspension compared with maizemealperlite amended soil Coniothyrium minitans was able to infect and reduce viability of sclerotia incorporated into the amended soil over the 6 month experiment with spore suspension significantly increasing infection compared with maizemealperlite inoculum Hygromycin B amendment of the agar significantly increased C minitans recovery from sclerotia especially when the population of secondary fungal colonisers was high

scholarly journals Efficacy of Mahapancha Gavya (MPG) in controlling damping-off in tomato caused by Pythium aphanidermatum

1970 ◽  
Vol 35 (1) ◽  
pp. 11-16
Author(s):  
Rakesh Kumar ◽  
Indra Hooda ◽  
SS Karwasra
Keyword(s):  
Disease Control ◽  
Integrated Control ◽  
Trichoderma Viride ◽  
Pythium Aphanidermatum ◽  
Integrated Treatment ◽  
Damping Off ◽  
Complete Control ◽  
Tomato Seedlings ◽  
Neem Leaf Extract

Maha Pancha Gavya (MPG), a concoction made from five cow products was tested for its toxicity against Pythium aphanidermatum (Edson) Fitz. and its antagonists at 5, 10, 25, and 50% concentration in in vitro to find out if it can be used in integration for the control of damping-off in tomato in nursery beds. MPG was very effective inihibiting the growth of P. aphanidermatum. At the highest concentration, the growth of the pathogen was negligible. Isolates of Trichoderma viride, T harzianum, and T. virens were also sensitive to MPG at all the concentrations. Their radial growth decreased, but it was fluffy in nature and sporulated profusely. MPG was not toxic against two bacterial antagonists i.e., Bacillus subtilis and Pseudomonas fluorescens. Soil application of 10% MPG to nursery beds improved seedling stand and gave upto 48.27% tlisease control, which was more than that given by individual antagonists. However, MPG improved disease control efficacy of all the antagonists when it was used in combination with them. Integrated treatment with MPG and B. subtilis gave maximum disease control (65.33%). MPG enhanced seedling growth and it was more in combination with T. viride and B. subtilis. MPG in integration with neem cake and neem leaf extract gave complete control of damping-off and maxium increase in height of the tomato seedlings. Keywords: Maha Panch Gavya (MPG); Trichoderma; Pythium aphanidermatum; integrated control; neem products; tomato; damping-off. DOI: 10.3329/bjar.v35i1.5862Bangladesh J. Agril. Res. 35(1) : 11-16, March 2010

scholarly journals Biocontrol of Lettuce Drop Caused by Sclerotinia sclerotiorum and S. minor in Desert Agroecosystems

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1625-1634 ◽  
Author(s):  
P. Chitrampalam ◽  
P. J. Figuli ◽  
M. E. Matheron ◽  
K. V. Subbarao ◽  
B. M. Pryor
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Field Experiments ◽  
Production Systems ◽  
Disease Incidence ◽  
Coniothyrium Minitans ◽  
Fungicide Sensitivity ◽  
Sensitivity Evaluation ◽  
Gliocladium Virens ◽  
Lettuce Drop

Field experiments were conducted over 2 years in Yuma County, AZ, and Imperial County, CA, to determine the efficacy of several biocontrol agents for the management of lettuce drop caused by Sclerotinia spp. Commercial formulations of Trichoderma harzianum (Plantshield, Supersivit), Gliocladium virens (Soilgard), Coniothyrium minitans (Contans), and Bacillus subtilis (Companion) were evaluated and compared with the chemical fungicide iprodione (Rovral) against Sclerotinia sclerotiorum and S. minor. A single application of biocontrol products or of Rovral did not reduce lettuce drop caused by either Sclerotinia species. However, two applications of Contans, one at planting and one at post-thinning, significantly reduced the incidence of lettuce drop caused by S. sclerotiorum and increased yield but had no effect on S. minor at both locations in both years. Two applications of other biocontrol products did not significantly reduce disease incidence despite medium to high recovery following application. In contrast, Contans was only sporadically recovered following application. In vitro fungicide sensitivity evaluation revealed that both Trichoderma and Gliocladium species were tolerant to iprodione, dicloran (Botran), and vinclozolin (Ronilan) up to 1,000 ppm a.i., whereas both Sclerotinia spp. and C. minitans were sensitive to all three fungicides above 1 ppm. In summary, Contans was the most effective treatment for the control of lettuce drop caused by S. sclerotiorum, but no treatment was effective against S. minor in the desert lettuce production systems.

scholarly journals IMPACT OF PESTICIDE TOLERANT SOIL BACTERIA ON DISEASE CONTROL, PLANT GROWTH PROMOTION AND SYSTEMIC RESISTANCE IN COWPEA

2021 ◽  
Vol 29 (4) ◽  
pp. 430-440
Author(s):  
Anuradha Bandopadhyay ◽  
Tina Roy ◽  
Nirmalendu Das
Keyword(s):  
Plant Growth ◽  
Disease Control ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Control Plant ◽  
Field Evaluation ◽  
Macrophomina Phaseolina ◽  
Systemic Resistance ◽  
Infested Soil

Cowpea, an annual legume, suffers from several disease symptoms caused by Macrophomina phaseolina. Rhizobacteria isolated from pesticide infested soil, identified by blast analysis as Bacillus cereus, Bacillus safensis, Pseudomonas donghuensis and Pseudomonas aeruginosa ascertained tolerant to at least 0.1% pesticides viz. methomyl, imidacloprid and carbendazim. In vitro antagonism against pathogen exhibited maximum by P. aeruginosa 63%. All rhizobacteria were bestowed with attributes responsible for pathogen control and plant growth promotion. Field evaluation resulted highest 75% disease control, enhancement of length, nodule counts, biomass or yield per plant by P. aeruginosa. All rhizobacteria induced systemic resistance in cowpea under challenged inoculation with pathogen by augmenting defensive enzyme production. Highest Phenylalanine Ammonia Lyase activity was expressed in P. aeruginosa treated plants 1.02 μMoles/ml/min, Polyphenol Oxidase by P. donghuensis 1.39 μMoles/ml/min, Chitinase by B. cereus 0.745 μMoles/ml/min and 400 percent relative activity of Peroxidase by P. aeruginosa. The rhizobacteria were prospective for plant disease control, growth promotion and as immunity boosters in pesticide and heavy metal infested toxic environment.

scholarly journals Cellulase Activity as a Mechanism for Suppression of Phytophthora Root Rot in Mulches

2011 ◽  
Vol 101 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Brantlee Spakes Richter ◽  
Kelly Ivors ◽  
Wei Shi ◽  
D. M. Benson
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Cellulase Activity ◽  
Enzyme Concentration ◽  
Disease Suppression ◽  
In Vitro Assays ◽  
Infested Soil ◽  
Phytophthora Root Rot ◽  
Standard Curve

Wood-based mulches are used in avocado production and are being tested on Fraser fir for reduction of Phytophthora root rot, caused by Phytophthora cinnamomi. Research with avocado has suggested a role of microbial cellulase enzymes in pathogen suppression through effects on the cellulosic cell walls of Phytophthora. This work was conducted to determine whether cellulase activity could account for disease suppression in mulch systems. A standard curve was developed to correlate cellulase activity in mulches with concentrations of a cellulase product. Based on this curve, cellulase activity in mulch samples was equivalent to a cellulase enzyme concentration of 25 U ml–1 or greater of product. Sustained exposure of P. cinnamomi to cellulase at 10 to 50 U ml–1 significantly reduced sporangia production, but biomass was only reduced with concentrations over 100 U ml–1. In a lupine bioassay, cellulase was applied to infested soil at 100 or 1,000 U ml–1 with three timings. Cellulase activity diminished by 47% between 1 and 15 days after application. Cellulase applied at 100 U ml–1 2 weeks before planting yielded activity of 20.08 μmol glucose equivalents per gram of soil water (GE g–1 aq) at planting, a level equivalent to mulch samples. Cellulase activity at planting ranged from 3.35 to 48.67 μmol GE g–1 aq, but no treatment significantly affected disease progress. Based on in vitro assays, cellulase activity in mulch was sufficient to impair sporangia production of P. cinnamomi, but not always sufficient to impact vegetative biomass.

scholarly journals Computational Design of a Molecularly Imprinted Polymer for the Biomonitoring of the Organophosphorous Metabolite Chlorferron

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 192
Author(s):  
Bakhtiyar Qader ◽  
Issam Hussain ◽  
Mark Baron ◽  
Rebeca Jiménez-Pérez ◽  
Guzmán Gil-Ramírez ◽  
...  
Keyword(s):  
Biological Samples ◽  
Limit Of Detection ◽  
Computational Design ◽  
Signal Change ◽  
Highly Sensitive ◽  
Limit Of Quantitation ◽  
Molecularly Imprinting Polymers ◽  
Mip Sensor ◽  
Parasitic Mites

Coumaphos is an organophosphorus compound used as insecticide and frequently used by beekeepers for the management of parasitic mites. The most important metabolite, chlorferron (CFN), has been identified in biological samples and foodstuff. The need to quickly identify the presence of typical metabolites, as an indication of interaction with coumaphos has driven the need to produce a highly sensitive electrochemical method for chlorferron analysis, based on molecularly imprinting polymers (MIP) technology. It showed irreversible behaviour with mixed diffusion/adsorption-controlled reactions at the electrode surface. A monoelectronic mechanism of reaction for oxidation has also been suggested. The linear range observed was from 0.158 to 75 µM. Median precision in terms of %RSD around 3% was also observed. For DPV, the limit of detection (LOD) and the limit of quantitation (LOQ) for the CFN-MIP were 0.158 µM and 0.48 µM, respectively. The obtained median % recovery was around 98%. The results were also validated to reference values obtained using GC-MS. Urine and human synthetic plasma spiked with CFN were used to demonstrate the usability of the method in biological samples, showing the potential for biomonitoring. The developed imprinted sensor showed maximum signal change less than 16.8% when related metabolites or pesticide were added to the mix, suggesting high selectivity of the MIP sensor toward CFN molecules. The results from in vitro metabolism of CMP analysed also demonstrates the potential for detection and quantification of CFN in environmental samples. The newly developed CFN-MIP sensor offers similar LoDs than chromatographic methods with shorter analysis time.

scholarly journals Nanoimprinted multifunctional nanoprobes for a homogeneous immunoassay in a top-down fabrication approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hubert Brueckl ◽  
Astrit Shoshi ◽  
Stefan Schrittwieser ◽  
Barbara Schmid ◽  
Pia Schneeweiss ◽  
...  
Keyword(s):  
Thin Film ◽  
Nanoimprint Lithography ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
In Vitro Diagnostics ◽  
Top Down ◽  
Highly Sensitive ◽  
Optical And Magnetic Properties ◽  
Lift Off

AbstractMultifunctional nanoparticles are discussed as versatile probes for homogeneous immunoassays for in-vitro diagnostics. Top-down fabrication allows to combine and tailor magnetic and plasmonic anisotropic properties. The combination of nanoimprint lithography, thin film deposition, and lift-off processing provides a top-down fabrication platform, which is both flexible and reliable. Here, we discuss the material compositions and geometrical designs of monodisperse multicomponent nanoparticles and their consequences on optical and magnetic properties. The rotational hydrodynamics of nanoparticles is measured and considered under the influence of magnetic shape anisotropy in the framework of the Stoner-Wohlfarth theory. The plasmon-optical properties are explained by discrete-dipole finite-element simulations. Rotational dynamical measurements of imprinted nanoprobes for two test proteins demonstrate the applicability as highly sensitive biomolecular nanoprobes.

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