Michel GIRAUD - Academia.edu (original) (raw)
Papers by Michel GIRAUD
HAL (Le Centre pour la Communication Scientifique Directe), 2018
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
HAL (Le Centre pour la Communication Scientifique Directe), Dec 1, 2017
Acta Horticulturae, 2021
"Since 2011, walnut trees orchards from southeastern France are attacked by a new pathogen: ... more "Since 2011, walnut trees orchards from southeastern France are attacked by a new pathogen: Colletotrichum."
PeerJ
Leaf blotch caused by Alternaria spp. is a common disease in apple-producing regions. The disease... more Leaf blotch caused by Alternaria spp. is a common disease in apple-producing regions. The disease is usually associated with one phylogenetic species and one species complex, Alternaria alternata and the Alternaria arborescens species complex (A. arborescens SC), respectively. Both taxa may include the Alternaria apple pathotype, a quarantine or regulated pathogen in several countries. The apple pathotype is characterized by the production of a host-selective toxin (HST) which is involved in pathogenicity towards the apple. A cluster of genes located on conditionally dispensable chromosomes (CDCs) is involved in the production of this HST (namely AMT in the case of the apple pathotype). Since 2016, leaf blotch and premature tree defoliation attributed to Alternaria spp. have been observed in apple-producing regions of central and south-eastern France. Our study aimed to identify the Alternaria species involved in apple tree defoliation and assess the presence of the apple pathotype ...
Scientific reports, Jan 17, 2018
Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diver... more Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diverse temperate and subtropical regions, walnut is primarily cultivated for its nuts. In France, Colletotrichum sp. on walnut was detected for the first time in 2007; in 2011 the disease led to 50-70% losses in nut production. A combined approach of metabarcoding analysis and multi-locus genetic characterization of isolated strains has been used for taxonomic designation and to study the genetic variability of this pathogen in France. Evidence indicates that four Colletotrichum species are associated with walnut in France: 3 belong to the C. acutatum species complex and 1 to the C. gloeosporioides species complex. Results also show that C. godetiae is the most abundant species followed by C. fioriniae; while C. nymphaeae and another Colletotrichum sp. belonging to the C. gloeosporioides complex are found rarely. Representative isolates of detected species were also used to confirm pathogeni...
Acta Horticulturae, 2010
Walnut blight, caused by Xanthomonas arboricola pv. juglandis is a major disease of Walnut in Fra... more Walnut blight, caused by Xanthomonas arboricola pv. juglandis is a major disease of Walnut in France, mainly responsible for necrosis on fruits and early nut drop before harvest. The population dynamics were studied over three years in orchards in the SouthWest of France, with comparison among orchards with different infestation levels. Samples of buds, leaves, flowers, pollen and fruits were collected from the beginning of April till the end of August, and the epiphytic population size of X. a. pv. juglandis was measured by plating dilutions of water extract on Tween Modified Medium. Population size broadly varies during the year from 10 3 to 10 7 cfu/g, increasing from budbreak, and remains stable after flowering. The level is a little lower in less infected orchards, suggesting that the expression of disease is more affected by pedo-climatic conditions than bacterial population level.
Scientific reports, Jan 17, 2018
Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diver... more Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diverse temperate and subtropical regions, walnut is primarily cultivated for its nuts. In France, Colletotrichum sp. on walnut was detected for the first time in 2007; in 2011 the disease led to 50-70% losses in nut production. A combined approach of metabarcoding analysis and multi-locus genetic characterization of isolated strains has been used for taxonomic designation and to study the genetic variability of this pathogen in France. Evidence indicates that four Colletotrichum species are associated with walnut in France: 3 belong to the C. acutatum species complex and 1 to the C. gloeosporioides species complex. Results also show that C. godetiae is the most abundant species followed by C. fioriniae; while C. nymphaeae and another Colletotrichum sp. belonging to the C. gloeosporioides complex are found rarely. Representative isolates of detected species were also used to confirm pathogeni...
Data in brief, 2018
This dataset presents two series of hyperspectral images of healthy and infected apple tree leave... more This dataset presents two series of hyperspectral images of healthy and infected apple tree leaves acquired daily, from two days after inoculation until an advanced stage of infection (11 days after inoculation). The hyperspectral images were calibrated by reflection correction and registered to match the geometry of one reference image. On the last experiment day, scab positions are provided.
Postharvest fruit diseases are a limiting factor for the long-term storage of apples. Gloeosporiu... more Postharvest fruit diseases are a limiting factor for the long-term storage of apples. Gloeosporium caused by the fungus Pezicula alba Guthrie is the main postharvest disease of apples. Today the protection from posharvest diseases is undertaken by products from benzimidazoles family. In the main french area of apples production, there are some resistant strains to this chemical family. In this case, fludioxonil, an active ingredient developped by Syngenta Agro in strong partnership with various institutes specialized in fruits storage, seems to be the right answer to protect fruits during their storage. Indeed, fludioxonil is the only one active ingredient from phenylpyrroles family and has demonstrated with preharvest application a very good level of efficacy against postharvest diseases of apples.
Tableau 1-Proportion de projections en période nocturne pour neuf lits de feuilles pendant six an... more Tableau 1-Proportion de projections en période nocturne pour neuf lits de feuilles pendant six ans (piège « Marchi ») : total des projections nocturnes et celles provoquées par une pluie en période nocturne. Encadré 2-Informations pratiques sur les pièges Piège « Burkard » voir www.burkard.co.uk Prix 2009 : 2 530 £ (env. 3 087 €) Attention, le modèle standard fonctionne sur secteur. Demander un appareil fonctionnant sur batterie 12V. Mycotrap : était fabriqué par Werner Siegfried de la station de Wädenswil en Suisse, aujourd'hui retraité. Depuis, il ne semble plus fabriqué. Contact possible : Andreas Naef
In Western Europe, except for some Mediterranean countries, most economic losses during storage o... more In Western Europe, except for some Mediterranean countries, most economic losses during storage of apples are due to Lenticel spot disease (commonly known as "Gloeosporium rot") caused by Neofabraea spp., and superficial scald. With a better knowledge of epidemiological data of Neofabraea alba, it is possible to reinforce the efficacy of the treatments. Nowadays, pre-harvest effective chemicals could be fludioxonil, pyrimethanil, boscalid + pyraclostrobin. Non chemical control is based on hot water postharvest treatment: it has been shown as very effective not only against both Neofabraea spp. and superficial scald, but also against Monilia fructigena and Phytophthora spp. Adjunction of formulated clove oil enhances the efficacy. Hot water treatment now represents a good alternative to chemical postharvest control and some European companies are selling commercially suitable dipping or drenching systems. Penicillium expansum is responsible for decays in storage, mainly from airborne inoculum in cold stores. Sanitation is recommended to avoid infection by Penicillium during storage; furthermore, certain antagonistic microorganisms (such as Candida spp.) are effective against P. expansum, Botrytis cinerea and M. fructigena, and are now allowed in some European countries. With the withdrawal of antioxidants, 1-MCP remains the only available chemical for postharvest treatment. Its efficacy has been shown against scald, and in addition this product reduces the incidence of several rots. Among the different modified atmospheres, the most effective are DCA, ILOS, ULO and extreme ULO. CA with ethylene control could be also useful. All the above methods of control are discussed in order to combine limited pre-harvest chemical treatments with alternative methods (integrated control).
Infos-Ctifl-n° 225 Résumé Dans les stations fruitières, l'eau sert à véhiculer les fruits. Potabl... more Infos-Ctifl-n° 225 Résumé Dans les stations fruitières, l'eau sert à véhiculer les fruits. Potable lors de sa première utilisation, l'eau se charge au fur et à mesure en matière organique. L'étude présentée a pour objectif d'évaluer le risque de contamination microbiologique pour les pommes en contact avec cette eau. La bactérie étudiée est E. coli, traceur de la contamination fécale. Un suivi de la qualité de l'eau et de la contamination des pommes réalisé dans deux stations fruitières durant un mois, a montré la faible contamination de l'eau des bains d'immersion. Aucun lot ne présente de E. coli sur pommes en sortie de conditionnement. Use of water in packing houses-Evaluation of the microbiological contamination risk of apple: case study on E. coli Water is used to convey fruit in packing houses. Although potable at the outset, the water gradually becomes laden with organic matter. The aim of the study described here is to assess the risk of microbiological contamination of apples that come in contact with this water. The bacterium under study is E. coli, an indicator of faecal contamination. Artifi This value is well below the limit values defi ned for pre-cut fruits and vegetables. A study monitoring water quality and contamination of apples for four weeks in two different packing houses has demonstrated the low level of contamination of the water in the immersion baths (< 40 cfu of E. coli per ml of water). The bacterium was not detected on any apple batches exiting the grading shed (E. coli detection limit: 10 cfu/g of product).
INFoS CTIFL oCToBRe 2012 N°285 teChniqUes CONSERvATION POmmE mIChEL gIRAud, AudE mORONvALLE, CTIF... more INFoS CTIFL oCToBRe 2012 N°285 teChniqUes CONSERvATION POmmE mIChEL gIRAud, AudE mORONvALLE, CTIFL résUmé Le groupe des gloeosporioses représente la plus fréquente des maladies fongiques de conservation de la pomme en Europe de l'Ouest, et le principal agent responsable en France est Neofabraea alba. La biologie et l'épidémiologie de cette espèce sont relativement mal connues. La source d'inoculum serait présente sur les branches des pommiers, peut-être aussi dans l'environnement du verger, et les spores sont véhiculées par la pluie vers les fruits, où elles pénètrent dans les lenticelles avant d'entrer en phase de latence. Les principaux paramètres intervenant dans le processus d'infection sont la durée d'humectation associée à une pluie, la température et le délai entre la date de récolte et l'épisode pluvieux.
HAL (Le Centre pour la Communication Scientifique Directe), 2018
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
HAL (Le Centre pour la Communication Scientifique Directe), Dec 1, 2017
Acta Horticulturae, 2021
"Since 2011, walnut trees orchards from southeastern France are attacked by a new pathogen: ... more "Since 2011, walnut trees orchards from southeastern France are attacked by a new pathogen: Colletotrichum."
PeerJ
Leaf blotch caused by Alternaria spp. is a common disease in apple-producing regions. The disease... more Leaf blotch caused by Alternaria spp. is a common disease in apple-producing regions. The disease is usually associated with one phylogenetic species and one species complex, Alternaria alternata and the Alternaria arborescens species complex (A. arborescens SC), respectively. Both taxa may include the Alternaria apple pathotype, a quarantine or regulated pathogen in several countries. The apple pathotype is characterized by the production of a host-selective toxin (HST) which is involved in pathogenicity towards the apple. A cluster of genes located on conditionally dispensable chromosomes (CDCs) is involved in the production of this HST (namely AMT in the case of the apple pathotype). Since 2016, leaf blotch and premature tree defoliation attributed to Alternaria spp. have been observed in apple-producing regions of central and south-eastern France. Our study aimed to identify the Alternaria species involved in apple tree defoliation and assess the presence of the apple pathotype ...
Scientific reports, Jan 17, 2018
Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diver... more Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diverse temperate and subtropical regions, walnut is primarily cultivated for its nuts. In France, Colletotrichum sp. on walnut was detected for the first time in 2007; in 2011 the disease led to 50-70% losses in nut production. A combined approach of metabarcoding analysis and multi-locus genetic characterization of isolated strains has been used for taxonomic designation and to study the genetic variability of this pathogen in France. Evidence indicates that four Colletotrichum species are associated with walnut in France: 3 belong to the C. acutatum species complex and 1 to the C. gloeosporioides species complex. Results also show that C. godetiae is the most abundant species followed by C. fioriniae; while C. nymphaeae and another Colletotrichum sp. belonging to the C. gloeosporioides complex are found rarely. Representative isolates of detected species were also used to confirm pathogeni...
Acta Horticulturae, 2010
Walnut blight, caused by Xanthomonas arboricola pv. juglandis is a major disease of Walnut in Fra... more Walnut blight, caused by Xanthomonas arboricola pv. juglandis is a major disease of Walnut in France, mainly responsible for necrosis on fruits and early nut drop before harvest. The population dynamics were studied over three years in orchards in the SouthWest of France, with comparison among orchards with different infestation levels. Samples of buds, leaves, flowers, pollen and fruits were collected from the beginning of April till the end of August, and the epiphytic population size of X. a. pv. juglandis was measured by plating dilutions of water extract on Tween Modified Medium. Population size broadly varies during the year from 10 3 to 10 7 cfu/g, increasing from budbreak, and remains stable after flowering. The level is a little lower in less infected orchards, suggesting that the expression of disease is more affected by pedo-climatic conditions than bacterial population level.
Scientific reports, Jan 17, 2018
Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diver... more Juglans regia (walnut) is a species belonging to the family Juglandaceae. Broadly spread in diverse temperate and subtropical regions, walnut is primarily cultivated for its nuts. In France, Colletotrichum sp. on walnut was detected for the first time in 2007; in 2011 the disease led to 50-70% losses in nut production. A combined approach of metabarcoding analysis and multi-locus genetic characterization of isolated strains has been used for taxonomic designation and to study the genetic variability of this pathogen in France. Evidence indicates that four Colletotrichum species are associated with walnut in France: 3 belong to the C. acutatum species complex and 1 to the C. gloeosporioides species complex. Results also show that C. godetiae is the most abundant species followed by C. fioriniae; while C. nymphaeae and another Colletotrichum sp. belonging to the C. gloeosporioides complex are found rarely. Representative isolates of detected species were also used to confirm pathogeni...
Data in brief, 2018
This dataset presents two series of hyperspectral images of healthy and infected apple tree leave... more This dataset presents two series of hyperspectral images of healthy and infected apple tree leaves acquired daily, from two days after inoculation until an advanced stage of infection (11 days after inoculation). The hyperspectral images were calibrated by reflection correction and registered to match the geometry of one reference image. On the last experiment day, scab positions are provided.
Postharvest fruit diseases are a limiting factor for the long-term storage of apples. Gloeosporiu... more Postharvest fruit diseases are a limiting factor for the long-term storage of apples. Gloeosporium caused by the fungus Pezicula alba Guthrie is the main postharvest disease of apples. Today the protection from posharvest diseases is undertaken by products from benzimidazoles family. In the main french area of apples production, there are some resistant strains to this chemical family. In this case, fludioxonil, an active ingredient developped by Syngenta Agro in strong partnership with various institutes specialized in fruits storage, seems to be the right answer to protect fruits during their storage. Indeed, fludioxonil is the only one active ingredient from phenylpyrroles family and has demonstrated with preharvest application a very good level of efficacy against postharvest diseases of apples.
Tableau 1-Proportion de projections en période nocturne pour neuf lits de feuilles pendant six an... more Tableau 1-Proportion de projections en période nocturne pour neuf lits de feuilles pendant six ans (piège « Marchi ») : total des projections nocturnes et celles provoquées par une pluie en période nocturne. Encadré 2-Informations pratiques sur les pièges Piège « Burkard » voir www.burkard.co.uk Prix 2009 : 2 530 £ (env. 3 087 €) Attention, le modèle standard fonctionne sur secteur. Demander un appareil fonctionnant sur batterie 12V. Mycotrap : était fabriqué par Werner Siegfried de la station de Wädenswil en Suisse, aujourd'hui retraité. Depuis, il ne semble plus fabriqué. Contact possible : Andreas Naef
In Western Europe, except for some Mediterranean countries, most economic losses during storage o... more In Western Europe, except for some Mediterranean countries, most economic losses during storage of apples are due to Lenticel spot disease (commonly known as "Gloeosporium rot") caused by Neofabraea spp., and superficial scald. With a better knowledge of epidemiological data of Neofabraea alba, it is possible to reinforce the efficacy of the treatments. Nowadays, pre-harvest effective chemicals could be fludioxonil, pyrimethanil, boscalid + pyraclostrobin. Non chemical control is based on hot water postharvest treatment: it has been shown as very effective not only against both Neofabraea spp. and superficial scald, but also against Monilia fructigena and Phytophthora spp. Adjunction of formulated clove oil enhances the efficacy. Hot water treatment now represents a good alternative to chemical postharvest control and some European companies are selling commercially suitable dipping or drenching systems. Penicillium expansum is responsible for decays in storage, mainly from airborne inoculum in cold stores. Sanitation is recommended to avoid infection by Penicillium during storage; furthermore, certain antagonistic microorganisms (such as Candida spp.) are effective against P. expansum, Botrytis cinerea and M. fructigena, and are now allowed in some European countries. With the withdrawal of antioxidants, 1-MCP remains the only available chemical for postharvest treatment. Its efficacy has been shown against scald, and in addition this product reduces the incidence of several rots. Among the different modified atmospheres, the most effective are DCA, ILOS, ULO and extreme ULO. CA with ethylene control could be also useful. All the above methods of control are discussed in order to combine limited pre-harvest chemical treatments with alternative methods (integrated control).
Infos-Ctifl-n° 225 Résumé Dans les stations fruitières, l'eau sert à véhiculer les fruits. Potabl... more Infos-Ctifl-n° 225 Résumé Dans les stations fruitières, l'eau sert à véhiculer les fruits. Potable lors de sa première utilisation, l'eau se charge au fur et à mesure en matière organique. L'étude présentée a pour objectif d'évaluer le risque de contamination microbiologique pour les pommes en contact avec cette eau. La bactérie étudiée est E. coli, traceur de la contamination fécale. Un suivi de la qualité de l'eau et de la contamination des pommes réalisé dans deux stations fruitières durant un mois, a montré la faible contamination de l'eau des bains d'immersion. Aucun lot ne présente de E. coli sur pommes en sortie de conditionnement. Use of water in packing houses-Evaluation of the microbiological contamination risk of apple: case study on E. coli Water is used to convey fruit in packing houses. Although potable at the outset, the water gradually becomes laden with organic matter. The aim of the study described here is to assess the risk of microbiological contamination of apples that come in contact with this water. The bacterium under study is E. coli, an indicator of faecal contamination. Artifi This value is well below the limit values defi ned for pre-cut fruits and vegetables. A study monitoring water quality and contamination of apples for four weeks in two different packing houses has demonstrated the low level of contamination of the water in the immersion baths (< 40 cfu of E. coli per ml of water). The bacterium was not detected on any apple batches exiting the grading shed (E. coli detection limit: 10 cfu/g of product).
INFoS CTIFL oCToBRe 2012 N°285 teChniqUes CONSERvATION POmmE mIChEL gIRAud, AudE mORONvALLE, CTIF... more INFoS CTIFL oCToBRe 2012 N°285 teChniqUes CONSERvATION POmmE mIChEL gIRAud, AudE mORONvALLE, CTIFL résUmé Le groupe des gloeosporioses représente la plus fréquente des maladies fongiques de conservation de la pomme en Europe de l'Ouest, et le principal agent responsable en France est Neofabraea alba. La biologie et l'épidémiologie de cette espèce sont relativement mal connues. La source d'inoculum serait présente sur les branches des pommiers, peut-être aussi dans l'environnement du verger, et les spores sont véhiculées par la pluie vers les fruits, où elles pénètrent dans les lenticelles avant d'entrer en phase de latence. Les principaux paramètres intervenant dans le processus d'infection sont la durée d'humectation associée à une pluie, la température et le délai entre la date de récolte et l'épisode pluvieux.