The Experts below are selected from a list of 2106 Experts worldwide ranked by ideXlab platform
Immaculada Viñas - One of the best experts on this subject based on the ideXlab platform.
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Improved Control of Postharvest Decay of Pears by the Combination of Candida sake (CPA-1) and Ammonium Molybdate
Phytopathology, 2002Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Maribel Abadias, Immaculada ViñasAbstract:ABSTRACT The potential enhancement of Candida sake (CPA-1) by Ammonium Molybdate to control blue and gray mold caused by Penicillium expansum and Botrytis cinerea, respectively, on Blanquilla pears was investigated. In laboratory trials, improved control of blue and gray molds was obtained with the application of Ammonium Molybdate (1, 5, 10, and 15 mM) alone or in combination with C. sake at 2 × 106 or 2 × 107 CFU ml-1 on Blanquilla pears stored at 20°C. In semicommercial trials at 1°C for 5 months, the efficacy of C. sake at 2 × 106 CFU ml-1 on reducing P. expansum and B. cinerea decay was enhanced more than 88% with the addition of Ammonium Molybdate 5 mM in the 1999-2000 season. In two seasons, the performance C. sake at 2 × 106 CFU ml-1 plus Ammonium Molybdate was similar to or greater than that of C. sake at 2 × 107 CFU ml-1. Similar control of blue mold was obtained on pears stored under low oxygen conditions. The preharvest application of Ammonium Molybdate did not reduce postharvest blue mold dec...
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Improvement of Candida sake biocontrol activity against post-harvest decay by the addition of Ammonium Molybdate.
Journal of applied microbiology, 2002Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Immaculada ViñasAbstract:Aim: To improve the efficacy of Candida sake by adding Ammonium Molybdate to control post-harvest decay in Golden Delicious apples. Methods and Results: In laboratory trials, C. sake 2 x 10(6) cfu ml(-1) plus 5 mmol l(-1) Ammonium Molybdate greatly reduced Penicillium expansum, Botrytis cinerea or Rhizopus stolonifer in apples stored at 20 degrees C for 7 days, and reduced by more than 90% blue and grey mould in apples stored at 1 degrees C for 60 days. The consistency of these results was maintained in semi-commercial trials at 1 degrees C in air and in a low oxygen atmosphere for 120 days. The pre-harvest application of C. sake 2 x 10(7) cfu ml(-1) plus 1 mmol l(-1) Ammonium Molybdate did not improve post-harvest biocontrol of blue mould. The population of C. sake significantly decreased in the presence of Ammonium Molybdate in apple wounds. Conclusion: The addition of Ammonium Molybdate at 5 mmol l(-1) to C. sake enhanced the efficacy of the antagonist to control post-harvest diseases on apples. Significance and Impact of the Study: Ammonium Molybdate significantly reduces the amount of C. sake biomass required to achieve post-harvest disease control, with a consequent reduction in costs. This may be useful in the industrial production of C. sake.
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Control of post-harvest decay of apples by pre-harvest and post-harvest application of Ammonium Molybdate.
Pest management science, 2001Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Xavier Ochoa De Eribe, Immaculada ViñasAbstract:Ammonium Molybdate was tested as a potential fungicide for use in apples (cv Golden Delicious) against blue and grey mould, important post-harvest diseases of pome fruits. In tests in vivo at 20 degrees C, Ammonium Molybdate (15 mM) reduced lesion diameters of Penicillium expansum, Botrytis cinerea and Rhizopus stolonifer by 84%, 88% and 100% respectively. When apples treated with Ammonium Molybdate were stored at 1 degree C for three months, a significant reduction in severity and incidence of P expansum and B cinerea was observed in both years of study (1998 and 1999). In the second year of the experiment the reduction in disease severity was greater than 88% for both pathogens, and the level of control was similar to, or greater than, that observed with the fungicide imazalil. When Ammonium Molybdate was applied as a pre-harvest treatment, a significant reduction in blue mould decay was observed after three months in cold storage. In vitro, Ammonium Molybdate greatly inhibited spore germination of P expansum and B cinerea, although better inhibition was obtained against grey mould. Ammonium diMolybdate, sodium Molybdate and potassium Molybdate were also tested in vitro in comparison with Ammonium Molybdate as inhibitors of spore germination, but only Ammonium Molybdate inhibited spore germination by more than 50%.
J Usall - One of the best experts on this subject based on the ideXlab platform.
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evaluation of food additives and low toxicity compounds as alternative chemicals for the control of penicillium digitatum and penicillium italicum on citrus fruit
Pest Management Science, 2002Co-Authors: Lluis Palou, Joeseph L Smilanick, Mariajose Aguilar, J Usall, Inmaculada VinasAbstract:The effectiveness of low-toxicity chemicals as possible alternatives to synthetic fungicides for the control of post-harvest green and blue moulds of citrus was evaluated. A preliminary selection of chemicals, mostly common food additives, was made through in vivo primary screenings with oranges artificially inoculated with Penicillium digitatum or P italicum. Selected compounds and mixtures were tested as heated solutions in small-scale trials. Immersion of artificially inoculated oranges or lemons for 120 s in solutions at 40.6 °C and natural pH of potassium sorbate (0.2 M), sodium benzoate (0.2 M) or mixtures (0.1 + 0.1 M) of potassium sorbate with sodium benzoate, sodium propionate or sodium acetate were the most effective organic acid salts tested and reduced green mould by 70–80% after 7 days of storage at 20 °C. The mixtures did not significantly enhance the effectiveness of potassium sorbate or sodium benzoate alone. These solutions were as effective as sodium carbonate or calcium polysulphide treatments and, in general, they were more effective on lemons than on oranges. Satisfactory control of green and blue moulds was obtained by dipping oranges for 150 s in solutions of sodium Molybdate (24.2 mM) or Ammonium Molybdate (1.0 mM) at 48 or 53 °C, but not at 20 °C. At 53 °C, however, the effectiveness of hot water was not enhanced by either Molybdate. Molybdenum salts at higher concentrations were phytotoxic and stained the fruit. At non-phytotoxic concentrations, the effectiveness of these solutions was more influenced by temperature than by concentration. In general, the inhibitory effects of all compounds tested were not fungicidal but fungistatic and not very persistent. In conclusion, potassium sorbate, sodium benzoate and Ammonium Molybdate, among the wide range of chemicals tested, were superior for the control of post-harvest Penicillium decay of citrus fruit. © 2002 Society of Chemical Industry
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evaluation of food additives and low toxicity compounds as alternative chemicals for the control of penicillium digitatum and penicillium italicum on citrus fruit
Pest Management Science, 2002Co-Authors: Lluis Palou, Joeseph L Smilanick, Mariajose Aguila, J Usall, Inmaculada VinasAbstract:The effectiveness of low-toxicity chemicals as possible alternatives to synthetic fungicides for the control of post-harvest green and blue moulds of citrus was evaluated. A preliminary selection of chemicals, mostly common food additives, was made through in vivo primary screenings with oranges artificially inoculated with Penicillium digitatum or P italicum. Selected compounds and mixtures were tested as heated solutions in small-scale trials. Immersion of artificially inoculated oranges or lemons for 120 s in solutions at 40.6 degrees C and natural pH of potassium sorbate (0.2 M), sodium benzoate (0.2 M) or mixtures (0.1 + 0.1 M) of potassium sorbate with sodium benzoate, sodium propionate or sodium acetate were the most effective organic acid salts tested and reduced green mould by 70-80% after 7 days of storage at 20 degrees C. The mixtures did not significantly enhance the effectiveness of potassium sorbate or sodium benzoate alone. These solutions were as effective as sodium carbonate or calcium polysulphide treatments and, in general, they were more effective on lemons than on oranges. Satisfactory control of green and blue moulds was obtained by dipping oranges for 150 s in solutions of sodium Molybdate (24.2 mM) or Ammonium Molybdate (1.0 mM) at 48 or 53 degrees C, but not at 20 degrees C. At 53 degrees C, however, the effectiveness of hot water was not enhanced by either Molybdate. Molybdenum salts at higher concentrations were phytotoxic and stained the fruit. At non-phytotoxic concentrations, the effectiveness of these solutions was more influenced by temperature than by concentration. In general, the inhibitory effects of all compounds tested were not fungicidal but fungistatic and not very persistent. In conclusion, potassium sorbate, sodium benzoate and Ammonium Molybdate, among the wide range of chemicals tested, were superior for the control of post-harvest Penicillium decay of citrus fruit.
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Improvement of Candida sake biocontrol activity against post-harvest decay by the addition of Ammonium Molybdate.
Journal of applied microbiology, 2002Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Immaculada ViñasAbstract:Aim: To improve the efficacy of Candida sake by adding Ammonium Molybdate to control post-harvest decay in Golden Delicious apples. Methods and Results: In laboratory trials, C. sake 2 x 10(6) cfu ml(-1) plus 5 mmol l(-1) Ammonium Molybdate greatly reduced Penicillium expansum, Botrytis cinerea or Rhizopus stolonifer in apples stored at 20 degrees C for 7 days, and reduced by more than 90% blue and grey mould in apples stored at 1 degrees C for 60 days. The consistency of these results was maintained in semi-commercial trials at 1 degrees C in air and in a low oxygen atmosphere for 120 days. The pre-harvest application of C. sake 2 x 10(7) cfu ml(-1) plus 1 mmol l(-1) Ammonium Molybdate did not improve post-harvest biocontrol of blue mould. The population of C. sake significantly decreased in the presence of Ammonium Molybdate in apple wounds. Conclusion: The addition of Ammonium Molybdate at 5 mmol l(-1) to C. sake enhanced the efficacy of the antagonist to control post-harvest diseases on apples. Significance and Impact of the Study: Ammonium Molybdate significantly reduces the amount of C. sake biomass required to achieve post-harvest disease control, with a consequent reduction in costs. This may be useful in the industrial production of C. sake.
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Improved Control of Postharvest Decay of Pears by the Combination of Candida sake (CPA-1) and Ammonium Molybdate
Phytopathology, 2002Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Maribel Abadias, Immaculada ViñasAbstract:ABSTRACT The potential enhancement of Candida sake (CPA-1) by Ammonium Molybdate to control blue and gray mold caused by Penicillium expansum and Botrytis cinerea, respectively, on Blanquilla pears was investigated. In laboratory trials, improved control of blue and gray molds was obtained with the application of Ammonium Molybdate (1, 5, 10, and 15 mM) alone or in combination with C. sake at 2 × 106 or 2 × 107 CFU ml-1 on Blanquilla pears stored at 20°C. In semicommercial trials at 1°C for 5 months, the efficacy of C. sake at 2 × 106 CFU ml-1 on reducing P. expansum and B. cinerea decay was enhanced more than 88% with the addition of Ammonium Molybdate 5 mM in the 1999-2000 season. In two seasons, the performance C. sake at 2 × 106 CFU ml-1 plus Ammonium Molybdate was similar to or greater than that of C. sake at 2 × 107 CFU ml-1. Similar control of blue mold was obtained on pears stored under low oxygen conditions. The preharvest application of Ammonium Molybdate did not reduce postharvest blue mold dec...
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Control of post-harvest decay of apples by pre-harvest and post-harvest application of Ammonium Molybdate.
Pest management science, 2001Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Xavier Ochoa De Eribe, Immaculada ViñasAbstract:Ammonium Molybdate was tested as a potential fungicide for use in apples (cv Golden Delicious) against blue and grey mould, important post-harvest diseases of pome fruits. In tests in vivo at 20 degrees C, Ammonium Molybdate (15 mM) reduced lesion diameters of Penicillium expansum, Botrytis cinerea and Rhizopus stolonifer by 84%, 88% and 100% respectively. When apples treated with Ammonium Molybdate were stored at 1 degree C for three months, a significant reduction in severity and incidence of P expansum and B cinerea was observed in both years of study (1998 and 1999). In the second year of the experiment the reduction in disease severity was greater than 88% for both pathogens, and the level of control was similar to, or greater than, that observed with the fungicide imazalil. When Ammonium Molybdate was applied as a pre-harvest treatment, a significant reduction in blue mould decay was observed after three months in cold storage. In vitro, Ammonium Molybdate greatly inhibited spore germination of P expansum and B cinerea, although better inhibition was obtained against grey mould. Ammonium diMolybdate, sodium Molybdate and potassium Molybdate were also tested in vitro in comparison with Ammonium Molybdate as inhibitors of spore germination, but only Ammonium Molybdate inhibited spore germination by more than 50%.
J. Robin Harris - One of the best experts on this subject based on the ideXlab platform.
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Negative staining and cryo-negative staining: applications in biology and medicine.
Methods of Molecular Biology, 2013Co-Authors: J. Robin Harris, Sacha De CarloAbstract:Negative staining is widely applicable to isolated viruses, protein molecules, macromolecular assemblies and fibrils, subcellular membrane fractions, liposomes and artificial membranes, synthetic DNA arrays, and also to polymer solutions and a variety of nanotechnology samples. Techniques are provided for the preparation of the necessary support films (continuous carbon and holey/perforated carbon). The range of suitable negative stains is presented, with some emphasis on the benefit of using Ammonium Molybdate and of negative stain-trehalose combinations. Protocols are provided for the single droplet negative staining technique (on continuous and holey carbon support films), the floating and carbon sandwich techniques in addition to the negative staining-carbon film (NS-CF) technique for randomly dispersed fragile molecules, 2D crystallization of proteins and for cleavage of cells and organelles. Immuno-negative staining and negative staining of affinity labeled complexes (e.g., biotin-streptavidin) are presented in some detail. The formation of immune complexes in solution for droplet negative staining is given, as is the use of carbon-plastic support films as an adsorption surface on which to perform immunolabeling or affinity experiments, prior to negative staining. Dynamic biological systems can be investigated by negative staining, where the time period is in excess of a few minutes, but there are possibilities to greatly reduce the time by rapid stabilization of molecular systems with uranyl acetate or tannic acid. The more recently developed cryo-negative staining procedures are also included: first, the high concentration Ammonium Molybdate procedure on holey carbon films and second, the carbon sandwich procedure using uranyl formate. Several electron micrographs showing examples of applications of negative staining techniques are included and the chapter is thoroughly referenced.
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Negative staining across holes: application to fibril and tubular structures.
Micron, 2007Co-Authors: J. Robin HarrisAbstract:The negative staining technique, when used with holey carbon support films, presents superior imaging conditions than is the case when samples are adsorbed to continuous carbon films. A demonstration of this negative staining approach is presented, using Ammonium Molybdate in combination with trehalose, applied to several fibrillar and tubular samples. Fibrils formed from the amyloid-β peptide and the protease inhibitor pepstain A spread very well unsupported across holes and the different polymorphic fibril forms can be readily assessed. However, tubular forms of amyloid-β have a tendency to be flattened, due to surface tension forces prior to and during specimen drying. Sub-fibril assembly forms and D-banded rat tail type 1 collagen fibres are presented. The air-dried collagen images produced are shown to contain almost as much detail as those obtainable by cryo-negative staining. Fragile DNA and DNA-protein nanotubes are also shown to yield superior quality images to those produced on continuous carbon films. The iron-storage protein, frataxin, creates elongated oligomeric assemblies, containing bound ferrihydrite microcrystals. The iron particles within these flexuous oligomers can be defined in the presence of Ammonium Molybdate, but they are more readily demonstrated if the frataxin is spread across holes in the presence of trehalose alone. The samples used here serve to show the likely benefit obtainable from negative staining across holes for a range of other fibrillar and tubular samples in biology, medicine and nanobiotechnology.
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Cryo-negative staining
Micron, 1998Co-Authors: Marc Adrian, Jacques Dubochet, Stephen D. Fuller, J. Robin HarrisAbstract:Abstract A procedure is presented for the preparation of thin layers of vitrified biological suspensions in the presence of Ammonium Molybdate, which we termcryo-negative staining. The direct blotting of sample plus stain solution on holey carbon supports produces thin aqueous films across the holes, which are routinely thiner than the aqueous film produced by conventional negative staining on a continuous carbon layer. Because of this, a higher than usual concentration of negative stain (ca. 16% rather than 2%) is required for cryo-negative staining in order to produce an optimal image contrast. The maintenance of the hydrated state, the absence of adsorption to a carbon film and associated sample flattening, together with reduced stain granularity, generates high contrast cryo-images of superior quality to conventional air-dry negative staining. Image features characteristic of unstained vitrified cryo-electron microscopic specimens are present, but with reverse contrast. Examples of cryo-negative staining of several particulate biological samples are shown, including bacteriophage T2, tobacco mosaic virus (TMV), bovine liver catalase crystals, tomato bushy stunt virus (TBSV), turnip yellow mosaic virus (TYMV), keyhole limpet hemocyanin (KLH) types 1 and 2, the 20S proteasome from moss and theE. coli chaperone GroEL. Densitometric quantitation of the mass-density of cryo-negatively stained bacteriophage T2 specimens before and after freeze-drying within the TEM indicates a water content of 30% in the vitreous specimen. Determination of the image resolution from cryo-negatively stained TMV rods and catalase crystals shows the presence of optical diffraction data to ca. 10A˚and 115A˚, respectively. For cryo-negatively stained vitrified catalase crystals, electron diffraction shows that atomic resolution is preserved (to better than 20 diffraction orders and less than 3A˚). The electron diffraction resolution is reduced to ca. 10A˚when catalase crystal specimens are prepared without freezing or when they are freeze-dried in the electron microscope. Thin vitrified films of TMV, TBSV and TYMV in the presence of 16% Ammonium Molybdate show a clear indication of two-dimensional (2-D) order, confirmed by single particle orientational analysis of TBSV and 2-D crystallographic analysis of TYMV. These observations are in accord with earlier claims that Ammonium Molybdate induces 2-D array and crystal formation from viruses and macromolecules during drying onto mica. Three-dimensional analysis of the TBSV sample using the tools of icosahedral reconstruction revealed that a significant fraction of the particles were distorted. A reconstruction from a subset of undistorted particles produced the characteristic T=3 dimer clustered structure of TBSV, although the spikes are shortened relative to the structure defined by X-ray crystallography. The 20S proteasome, GroEL, catalase, bacteriophage T2, TMV, TBSV and TYMV all show no indication of sample instability during cryo-negative staining. However, detectable dissociation of the KLH2 oligomers in the presence of the high concentration of Ammonium Molybdate conforms with existing knowledge on the Molybdate-induced dissociation of this molecule. This indicates that the possibility of sample-stain interaction in solution, prior to vitrification, must always be carefully assessed.
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Keyhole limpet haemocyanin: negative staining in the presence of trehalose
Micron, 1995Co-Authors: J. Robin Harris, Wolfgang Gebauer, Jurgen MarklAbstract:Abstract Samples of unpurified and purified haemocyanin from the giant keyhole limpet Megathura crenulata have been studied by transmission electron microscopy (TEM) using mixtures of trehalose with the negative stains, uranyl acetate and Ammonium Molybdate. Trehalose is a known protein preservative during air and freeze drying, UV irradiation and high temperatures, and therefore offers the possibility of protecting proteins during the drying of negatively-stained specimens and their subsequent electron microscopical study. Evidence is presented that trehalose possesses satisfactory stability within the electron beam during conventional room temperature, negative-staining studies. The combination of negative stain and trehalose generates a deeper layer of amorphous stain around and within the keyhole limpet haemocyanin (KLH) di- and multidecamers, thereby increasing protein mobility and the generation of a range of tilted images, alongside the more usually observed end-on and side-on image projections. The concentration of uranyl acetate and Ammonium Molybdate has been increased to 4 and 5%, respectively, in the presence of 1% trehalose, in order to generate satisfactory image contrast. This is because of the reduction by trehalose of the net mass thickness of the dried negative stain-carbohydrate mixture compared to for an equivalent thickness of stain alone. The study of these specimens at low temperatures (−175°C) offers the possibility of superior structural preservation.
Carla Nunes - One of the best experts on this subject based on the ideXlab platform.
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Improved Control of Postharvest Decay of Pears by the Combination of Candida sake (CPA-1) and Ammonium Molybdate
Phytopathology, 2002Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Maribel Abadias, Immaculada ViñasAbstract:ABSTRACT The potential enhancement of Candida sake (CPA-1) by Ammonium Molybdate to control blue and gray mold caused by Penicillium expansum and Botrytis cinerea, respectively, on Blanquilla pears was investigated. In laboratory trials, improved control of blue and gray molds was obtained with the application of Ammonium Molybdate (1, 5, 10, and 15 mM) alone or in combination with C. sake at 2 × 106 or 2 × 107 CFU ml-1 on Blanquilla pears stored at 20°C. In semicommercial trials at 1°C for 5 months, the efficacy of C. sake at 2 × 106 CFU ml-1 on reducing P. expansum and B. cinerea decay was enhanced more than 88% with the addition of Ammonium Molybdate 5 mM in the 1999-2000 season. In two seasons, the performance C. sake at 2 × 106 CFU ml-1 plus Ammonium Molybdate was similar to or greater than that of C. sake at 2 × 107 CFU ml-1. Similar control of blue mold was obtained on pears stored under low oxygen conditions. The preharvest application of Ammonium Molybdate did not reduce postharvest blue mold dec...
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Improvement of Candida sake biocontrol activity against post-harvest decay by the addition of Ammonium Molybdate.
Journal of applied microbiology, 2002Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Immaculada ViñasAbstract:Aim: To improve the efficacy of Candida sake by adding Ammonium Molybdate to control post-harvest decay in Golden Delicious apples. Methods and Results: In laboratory trials, C. sake 2 x 10(6) cfu ml(-1) plus 5 mmol l(-1) Ammonium Molybdate greatly reduced Penicillium expansum, Botrytis cinerea or Rhizopus stolonifer in apples stored at 20 degrees C for 7 days, and reduced by more than 90% blue and grey mould in apples stored at 1 degrees C for 60 days. The consistency of these results was maintained in semi-commercial trials at 1 degrees C in air and in a low oxygen atmosphere for 120 days. The pre-harvest application of C. sake 2 x 10(7) cfu ml(-1) plus 1 mmol l(-1) Ammonium Molybdate did not improve post-harvest biocontrol of blue mould. The population of C. sake significantly decreased in the presence of Ammonium Molybdate in apple wounds. Conclusion: The addition of Ammonium Molybdate at 5 mmol l(-1) to C. sake enhanced the efficacy of the antagonist to control post-harvest diseases on apples. Significance and Impact of the Study: Ammonium Molybdate significantly reduces the amount of C. sake biomass required to achieve post-harvest disease control, with a consequent reduction in costs. This may be useful in the industrial production of C. sake.
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Control of post-harvest decay of apples by pre-harvest and post-harvest application of Ammonium Molybdate.
Pest management science, 2001Co-Authors: Carla Nunes, J Usall, Neus Teixidó, Xavier Ochoa De Eribe, Immaculada ViñasAbstract:Ammonium Molybdate was tested as a potential fungicide for use in apples (cv Golden Delicious) against blue and grey mould, important post-harvest diseases of pome fruits. In tests in vivo at 20 degrees C, Ammonium Molybdate (15 mM) reduced lesion diameters of Penicillium expansum, Botrytis cinerea and Rhizopus stolonifer by 84%, 88% and 100% respectively. When apples treated with Ammonium Molybdate were stored at 1 degree C for three months, a significant reduction in severity and incidence of P expansum and B cinerea was observed in both years of study (1998 and 1999). In the second year of the experiment the reduction in disease severity was greater than 88% for both pathogens, and the level of control was similar to, or greater than, that observed with the fungicide imazalil. When Ammonium Molybdate was applied as a pre-harvest treatment, a significant reduction in blue mould decay was observed after three months in cold storage. In vitro, Ammonium Molybdate greatly inhibited spore germination of P expansum and B cinerea, although better inhibition was obtained against grey mould. Ammonium diMolybdate, sodium Molybdate and potassium Molybdate were also tested in vitro in comparison with Ammonium Molybdate as inhibitors of spore germination, but only Ammonium Molybdate inhibited spore germination by more than 50%.
Inmaculada Vinas - One of the best experts on this subject based on the ideXlab platform.
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evaluation of food additives and low toxicity compounds as alternative chemicals for the control of penicillium digitatum and penicillium italicum on citrus fruit
Pest Management Science, 2002Co-Authors: Lluis Palou, Joeseph L Smilanick, Mariajose Aguilar, J Usall, Inmaculada VinasAbstract:The effectiveness of low-toxicity chemicals as possible alternatives to synthetic fungicides for the control of post-harvest green and blue moulds of citrus was evaluated. A preliminary selection of chemicals, mostly common food additives, was made through in vivo primary screenings with oranges artificially inoculated with Penicillium digitatum or P italicum. Selected compounds and mixtures were tested as heated solutions in small-scale trials. Immersion of artificially inoculated oranges or lemons for 120 s in solutions at 40.6 °C and natural pH of potassium sorbate (0.2 M), sodium benzoate (0.2 M) or mixtures (0.1 + 0.1 M) of potassium sorbate with sodium benzoate, sodium propionate or sodium acetate were the most effective organic acid salts tested and reduced green mould by 70–80% after 7 days of storage at 20 °C. The mixtures did not significantly enhance the effectiveness of potassium sorbate or sodium benzoate alone. These solutions were as effective as sodium carbonate or calcium polysulphide treatments and, in general, they were more effective on lemons than on oranges. Satisfactory control of green and blue moulds was obtained by dipping oranges for 150 s in solutions of sodium Molybdate (24.2 mM) or Ammonium Molybdate (1.0 mM) at 48 or 53 °C, but not at 20 °C. At 53 °C, however, the effectiveness of hot water was not enhanced by either Molybdate. Molybdenum salts at higher concentrations were phytotoxic and stained the fruit. At non-phytotoxic concentrations, the effectiveness of these solutions was more influenced by temperature than by concentration. In general, the inhibitory effects of all compounds tested were not fungicidal but fungistatic and not very persistent. In conclusion, potassium sorbate, sodium benzoate and Ammonium Molybdate, among the wide range of chemicals tested, were superior for the control of post-harvest Penicillium decay of citrus fruit. © 2002 Society of Chemical Industry
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evaluation of food additives and low toxicity compounds as alternative chemicals for the control of penicillium digitatum and penicillium italicum on citrus fruit
Pest Management Science, 2002Co-Authors: Lluis Palou, Joeseph L Smilanick, Mariajose Aguila, J Usall, Inmaculada VinasAbstract:The effectiveness of low-toxicity chemicals as possible alternatives to synthetic fungicides for the control of post-harvest green and blue moulds of citrus was evaluated. A preliminary selection of chemicals, mostly common food additives, was made through in vivo primary screenings with oranges artificially inoculated with Penicillium digitatum or P italicum. Selected compounds and mixtures were tested as heated solutions in small-scale trials. Immersion of artificially inoculated oranges or lemons for 120 s in solutions at 40.6 degrees C and natural pH of potassium sorbate (0.2 M), sodium benzoate (0.2 M) or mixtures (0.1 + 0.1 M) of potassium sorbate with sodium benzoate, sodium propionate or sodium acetate were the most effective organic acid salts tested and reduced green mould by 70-80% after 7 days of storage at 20 degrees C. The mixtures did not significantly enhance the effectiveness of potassium sorbate or sodium benzoate alone. These solutions were as effective as sodium carbonate or calcium polysulphide treatments and, in general, they were more effective on lemons than on oranges. Satisfactory control of green and blue moulds was obtained by dipping oranges for 150 s in solutions of sodium Molybdate (24.2 mM) or Ammonium Molybdate (1.0 mM) at 48 or 53 degrees C, but not at 20 degrees C. At 53 degrees C, however, the effectiveness of hot water was not enhanced by either Molybdate. Molybdenum salts at higher concentrations were phytotoxic and stained the fruit. At non-phytotoxic concentrations, the effectiveness of these solutions was more influenced by temperature than by concentration. In general, the inhibitory effects of all compounds tested were not fungicidal but fungistatic and not very persistent. In conclusion, potassium sorbate, sodium benzoate and Ammonium Molybdate, among the wide range of chemicals tested, were superior for the control of post-harvest Penicillium decay of citrus fruit.