The Experts below are selected from a list of 921 Experts worldwide ranked by ideXlab platform

William Deasy - One of the best experts on this subject based on the ideXlab platform.

  • development and validation of a spme gc ms method for in situ passive sampling of root volatiles from glasshouse grown broccoli plants undergoing below ground herbivory by larvae of cabbage root fly Delia radicum l
    Phytochemical Analysis, 2016
    Co-Authors: William Deasy, Tom Shepherd, Colin J Alexander, Nicholas A E Birch, Andrew K Evans
    Abstract:

    Introduction Research on plant root chemical ecology has benefited greatly from recent developments in analytical chemistry. Numerous reports document techniques for sampling root volatiles, although only a limited number describe in situ collection. Objectives To demonstrate a new method for non-invasive in situ passive sampling using solid phase micro extraction (SPME), from the immediate vicinity of growing roots. Methods SPME fibres inserted into polyfluorotetrafluoroethylene (PTFE) sampling tubes located in situ which were either perforated, covered with stainless steel mesh or with microporous PTFE tubing, were used for non-invasive sub-surface sampling of root volatiles from glasshouse-grown broccoli. Sampling methods were compared with above surface headspace collection using Tenax TA. The roots were either mechanically damaged or infested with Delia radicum larvae. Principal component analysis (PCA) was used to investigate the effect of damage on the composition of volatiles released by broccoli roots. Results Analyses by gas chromatography-mass spectrometry (GC-MS) with SPME and automated thermal desorption (ATD) confirmed that sulphur compounds, showing characteristic temporal emission patterns, were the principal volatiles released by roots following insect larval damage. Use of SPME with in situ perforated PTFE sampling tubes was the most robust method for out-of-lab sampling. Conclusion This study describes a new method for non-invasive passive sampling of volatiles in situ from intact and insect damaged roots using SPME. The method is highly suitable for remote sampling and has potential for wide application in chemical ecology/root/soil research. Copyright © 2016 John Wiley & Sons, Ltd.

  • field based evaluation of a novel spme gc ms method for investigation of below ground interaction between brassica roots and larvae of cabbage root fly Delia radicum l
    Phytochemical Analysis, 2016
    Co-Authors: William Deasy, Tom Shepherd, Colin J Alexander, Nicholas A E Birch, Andrew K Evans
    Abstract:

    Introduction Collection of volatiles from plant roots poses technical challenges due to difficulties accessing the soil environment without damaging the roots. Objectives To validate a new non-invasive method for passive sampling of root volatiles in situ, from plants grown under field conditions, using solid phase micro-extraction (SPME). Methods SPME fibres were inserted into perforated polytetrafluoroethene (PTFE) tubes positioned in the soil next to broccoli plants for collection of root volatiles pre- and post-infestation with Delia radicum larvae. After sample analysis by gas chromatography-mass spectrometry (GC-MS), principal component analysis (PCA) was applied to determine differences in the profiles of volatiles between samples. Results GC-MS analysis revealed that this method can detect temporal changes in root volatiles emitted before and after Delia radicum damage. PCA showed that samples collected pre- and post-infestation were compositionally different due to the presence of root volatiles induced by D. radicum feeding. Sulphur containing compounds, in particular, accounted for the differences observed. Root volatiles emission patterns post-infestation are thought to follow the feeding and developmental progress of larvae. Conclusion This study shows that volatiles released by broccoli roots can be collected in situ using SPME fibres within perforated PTFE tubes under field conditions. Plants damaged by Delia radicum larvae could be distinguished from plants sampled pre-infestation and soil controls on the basis of larval feeding-induced sulphur-containing volatiles. These results show that this new method is a powerful tool for non-invasive sampling of root volatiles below-ground. Copyright © 2016 John Wiley & Sons, Ltd.

Anne-marie Cortesero - One of the best experts on this subject based on the ideXlab platform.

  • Assessing the relationship between pest density and plant damage: a case study with the belowground herbivore Delia radicum (Diptera: Anthomyiidae) on broccoli
    Applied Entomology and Zoology, 2019
    Co-Authors: Xavier Mesmin, Anne-marie Cortesero, Vincent Faloya, Marie Vincent, Yann Tricault, Vianney Estorgues, Loïc Daniel, Anne Le Ralec
    Abstract:

    For many crops, we have poor knowledge about the relationship between pest density and damage. However, investigating pest harmfulness is particularly relevant currently in the search for alternative crop protection strategies that are unlikely to totally suppress pest populations. Here, we assessed the harmfulness of Delia radicum (L.) (Diptera: Anthomyiidae) on broccoli ( Brassica oleracea var. italica Plenck). We worked inside insect-proof cages set up in the field with additional pitfall traps to remove ground-dwelling predators. Plants were manually infested with 10 levels of pest density ranging 0–100 individuals per plant, following a natural infestation pattern. Surprisingly, no plants died but almost 100% of the pests introduced died over the course of the experiment. However, all broccoli development and growth traits were negatively correlated with pest density and broccoli head mass at harvest decreased linearly with pest density. The observation over time of development and growth traits showed evidence of plant compensation, suggesting that the head mass of individual plants may have reached similar values if allowed to fully mature. The relationship between pest density and damage, together with forecast models of pest population dynamics could be used to develop decision support tools assessing the relevance of preventative treatments.

  • one more step toward a push pull strategy combining both a trap crop and plant volatile organic compounds against the cabbage root fly Delia radicum
    Environmental Science and Pollution Research, 2018
    Co-Authors: F Lamy, Sébastien Dugravot, Anne-marie Cortesero, Valerie Chaminade, Vincent Faloya, Denis Poinsot
    Abstract:

    The “push-pull” strategy aims at manipulating insect pest behavior using a combination of attractive and repulsive stimuli using either plants derived volatile organic compounds or insect host plant preferences. In a field experiment using broccoli as a crop, we combined in a “push-pull” context the oviposition deterrent effect of dimethyl disulfide and the attractive effect of a Chinese cabbage strip enhanced with Z-3-hexenyl-acetate. The push component dimethyl disulfide reduced Delia radicum L. (Diptera: Anthomyiidae) oviposition on broccoli by nearly 30%, and applying Z-3-hexenyl-acetate in the pull component of Chinese cabbage increased it by 40%. Moreover, pest infestation was 40% higher in Chinese cabbage compared to broccoli and parasitism by Trybliographa rapae Westwood (Hymenoptera: Figitidae) was four times higher on this trap plant. In addition, lab experiments confirmed that Chinese cabbage is a more suitable host plant than broccoli for the cabbage root fly. Taken together, our results demonstrate the technical possibility of using a push-pull strategy to manipulate the egg-laying behavior of D. radicum in the field.

  • of Systematic Reviews
    2016
    Co-Authors: S P Pierre, Sébastien Dugravot, Anne-marie Cortesero, M R Herve, H M Hassan, N M Van Dam, Cesar Rodriguez-saona Rutgers, Christelle A. M. Robert, Max Planck
    Abstract:

    doi: 10.3389/fpls.2013.00305 Belowground induction by Delia radicum or phytohormones affect aboveground herbivore communities on field-grown broccol

  • Maximum likelihood tree of Spiroplasma spp. obtained from the 16S V4-V5 fragment.
    2016
    Co-Authors: Mikaël Bili, Anne-marie Cortesero, Christophe Mougel, Jean Pierre Gauthier, Gwennola Ermel, Jean Christophe Simon, Yannick Outreman, Sébastien Terrat, Frédérique Mahéo, Denis Poinsot
    Abstract:

    Information is presented in the following order: bacteria name; host name in brackets (when available); OTU number for Delia radicum, Aleochara bilineata, Aleochara bipustulata and Trybliographa rapae. Bootstrap values (≥60; black) are given for each branch. Scaling is expressed in the proportion of substituted bases per site. Roman letters indicate serological groups.

  • Maximum likelihood tree of Wolbachia spp. obtained from the 16S V4-V5 fragment.
    2016
    Co-Authors: Mikaël Bili, Anne-marie Cortesero, Christophe Mougel, Jean Pierre Gauthier, Gwennola Ermel, Jean Christophe Simon, Yannick Outreman, Sébastien Terrat, Frédérique Mahéo, Denis Poinsot
    Abstract:

    Information is presented in the following order: bacteria name; host name in brackets (when available); OTU number for Delia radicum, Aleochara bilineata, Aleochara bipustulata and Trybliographa rapae. Bootstrap values (≥60; black) are given for each branch. Scaling is expressed in the proportion of substituted bases per site. Capital letters A to M refer to Wolbachia ‘supergroups’.

Cortesero Anne-marie - One of the best experts on this subject based on the ideXlab platform.

  • Influence of soil tillage on natural regulation of the cabbage root fly Delia radicum in brassicaceous crops
    'Elsevier BV', 2020
    Co-Authors: Mesmin Xavier, Cortesero Anne-marie, Faloya Vincent, Plantegenest Manuel, Daniel Loïc, Le Ralec Anne
    Abstract:

    International audienceGround dwelling predators provide regulation services of several insect pests. Enhancing these services may be a step toward integrated crop protection. Many studies have shown that soil tillage is deleterious to ground dwelling predators but pest regulation processes and services have rarely been measured. We performed an experiment to study whether simplifying soil tillage before the establishment of spring broccoli enhanced ground dwelling predator populations and the control they provide on Delia radicum. The direct effect of tillage on arthropods was assessed by comparing their emergence rates in plots differing in soil tillage management. The natural regulation service was assessed by comparing a control and an exclusion treatment in which predators were removed. The effect of soil tillage on carabids, spiders and staphylinids did not match the gradient of disturbance induced by tillage treatments. Tillage did not appear to affect the predators that likely contribute to D. radicum regulation. Consistently, the number of pests suppressed and the root injuries were unaffected by tillage treatments. The main deleterious effect of soil tillage was on the emergence of those carabid species that overwinter partly as larvae, suggesting that spring tillage could affect pest control in the following crops

  • Assessing the relationship between pest density and plant damage: a case study with the belowground herbivore Delia radicum (Diptera: Anthomyiidae) on broccoli
    'Springer Science and Business Media LLC', 2019
    Co-Authors: Mesmin Xavier, Cortesero Anne-marie, Faloya Vincent, Daniel Loïc, Vincent Marie, Tricault Yann, Estorgues Vianney, Le Ralec Anne
    Abstract:

    International audienceFor many crops, we have poor knowledge about the relationship between pest density and damage. However, investigating pest harmfulness is particularly relevant currently in the search for alternative crop protection strategies that are unlikely to totally suppress pest populations. Here, we assessed the harmfulness of Delia radicum (L.) (Diptera: Anthomyiidae) on broccoli (Brassica oleracea var. italica Plenck). We worked inside insect-proof cages set up in the field with additional pitfall traps to remove ground-dwelling predators. Plants were manually infested with 10 levels of pest density ranging 0–100 individuals per plant, following a natural infestation pattern. Surprisingly, no plants died but almost 100% of the pests introduced died over the course of the experiment. However, all broccoli development and growth traits were negatively correlated with pest density and broccoli head mass at harvest decreased linearly with pest density. The observation over time of development and growth traits showed evidence of plant compensation, suggesting that the head mass of individual plants may have reached similar values if allowed to fully mature. The relationship between pest density and damage, together with forecast models of pest population dynamics could be used to develop decision support tools assessing the relevance of preventative treatments

  • Influence of the symbiont Wolbachia on life history traits of the cabbage root fly (Delia radicum).
    'Elsevier BV', 2018
    Co-Authors: Lopez Valérie, Cortesero Anne-marie, Poinso Denis
    Abstract:

    International audienceWolbachia is an endocellular bacteria infecting arthropods and nematodes and is only transmitted vertically by females via the cytoplasm of the egg. It is often a manipulator of host reproduction, causing cytoplasmic incompatibility, thelytokous parthenogenesis, feminization or male killing, which all increase the proportion of infected females in the population. However, Wolbachia can modify life history traits of the host without causing the above phenotypes and each species illustrates the variability of relationships between this remarkably versatile symbiont and its many hosts. We have measured maternal transmission and the impact of a natural Wolbachia infection in the cabbage root fly Delia radicum, a major agricultural pest. We used a population that is polymorphic for the infection to ensure similar genetic and microbiome backgrounds between groups. Maternal transmission of the infection was 100% in our sample. We found no evidence of cytoplasmic incompatibility, thelytokous parthenogenesis, feminization nor male killing. Wolbachia infection significantly reduced hatch rate in infected eggs (by 10%) but improved larvo-nymphal viability sufficiently so that infected eggs nevertheless yielded as many adults as uninfected ones, albeit with a 1.5% longer total development time. Starved and infected ovipositing females suffered significantly reduced viability (20% higher mortality during a 3-day oviposition period) than uninfected females, but mortality was not higher in starved virgin females nor in starved males, suggesting that the energetic cost of the infection is only revealed in extreme conditions. Wolbachia had no effect on egg hatch time or offspring size. The apparently 100% vertical transmission and the significant but mutually compensating effects found suggest that infection might be nearly benign in this host and might only drift slowly, which would explain why the infection rate has been stable in our laboratory (approximately 50% individuals infected) for at least 30 generations

  • One more step toward a push-pull strategy combining both a trap crop and plant volatile organic compounds against the cabbage root fly Delia radicum.
    'Springer Science and Business Media LLC', 2018
    Co-Authors: Lamy Fabrice, Cortesero Anne-marie, Dugravot Sébastien, Chaminade Valérie, Faloya Vincent, Poinsot Denis
    Abstract:

    International audienceThe "push-pull" strategy aims at manipulating insect pest behavior using a combination of attractive and repulsive stimuli using either plants derived volatile organic compounds or insect host plant preferences. In a field experiment using broccoli as a crop, we combined in a "push-pull" context the oviposition deterrent effect of dimethyl disulfide and the attractive effect of a Chinese cabbage strip enhanced with Z-3-hexenyl-acetate. The push component dimethyl disulfide reduced Delia radicum L. (Diptera: Anthomyiidae) oviposition on broccoli by nearly 30%, and applying Z-3-hexenyl-acetate in the pull component of Chinese cabbage increased it by 40%. Moreover, pest infestation was 40% higher in Chinese cabbage compared to broccoli and parasitism by Trybliographa rapae Westwood (Hymenoptera: Figitidae) was four times higher on this trap plant. In addition, lab experiments confirmed that Chinese cabbage is a more suitable host plant than broccoli for the cabbage root fly. Taken together, our results demonstrate the technical possibility of using a push-pull strategy to manipulate the egg-laying behavior of D. radicum in the field

  • Field and laboratory selection of brassicaceous plants that differentially affect infestation levels by Delia radicum
    'Wiley', 2015
    Co-Authors: Kergunteuil Alan, Cortesero Anne-marie, Chaminade Valérie, Le Ralec Anne, Dourlot Sonia, Paty Chrystelle, Dugravot Sébastien
    Abstract:

    International audienceSeveral plant traits control plant-insect interactions and shape host range of herbivorous insects according to their degree of dietary specialization. Understanding how plant species diversity influences herbivore infestations is of interest for the development of alternative crop protection strategies. In a pest management context, an appropriate selection of plants can modify pest distribution at the field scale. To develop a push-pull' strategy against the cabbage root fly, Delia radicum, we conducted a field study to both determine which plants exhibit contrasted pest infestation levels and to evaluate their influence on egg predation activity. Our field experiment reveals that infestation levels of brassicaceous plants by the cabbage root fly in the field can vary considerably according to plant genotype and species, while the number of predated eggs is only slightly affected by plant species. Olfactometry studies carried out under laboratory conditions revealed that plants harbouring the highest number of eggs in the field were also highly attractive, suggesting that olfactory stimuli are responsible, at least partially, for the differential infestation levels observed in the field. In a push-pull' context, this study demonstrates that different brassicaceous plants could be used to redistribute cabbage root flies in broccoli crops without compromising herbivore control by natural enemies. In addition, the importance of plant volatiles for infestation levels suggests a potential for developing a semiochemically assisted push-pull' system in which trap plants would be enhanced by synthetic release of attractive compounds

Kergunteuil Alan - One of the best experts on this subject based on the ideXlab platform.

  • Field and laboratory selection of brassicaceous plants that differentially affect infestation levels by Delia radicum
    'Wiley', 2015
    Co-Authors: Kergunteuil Alan, Cortesero Anne-marie, Chaminade Valérie, Le Ralec Anne, Dourlot Sonia, Paty Chrystelle, Dugravot Sébastien
    Abstract:

    International audienceSeveral plant traits control plant-insect interactions and shape host range of herbivorous insects according to their degree of dietary specialization. Understanding how plant species diversity influences herbivore infestations is of interest for the development of alternative crop protection strategies. In a pest management context, an appropriate selection of plants can modify pest distribution at the field scale. To develop a push-pull' strategy against the cabbage root fly, Delia radicum, we conducted a field study to both determine which plants exhibit contrasted pest infestation levels and to evaluate their influence on egg predation activity. Our field experiment reveals that infestation levels of brassicaceous plants by the cabbage root fly in the field can vary considerably according to plant genotype and species, while the number of predated eggs is only slightly affected by plant species. Olfactometry studies carried out under laboratory conditions revealed that plants harbouring the highest number of eggs in the field were also highly attractive, suggesting that olfactory stimuli are responsible, at least partially, for the differential infestation levels observed in the field. In a push-pull' context, this study demonstrates that different brassicaceous plants could be used to redistribute cabbage root flies in broccoli crops without compromising herbivore control by natural enemies. In addition, the importance of plant volatiles for infestation levels suggests a potential for developing a semiochemically assisted push-pull' system in which trap plants would be enhanced by synthetic release of attractive compounds

  • Characterizing volatiles and attractiveness of five brassicaceous plants with potential for a 'push-pull' strategy toward the cabbage root fly, Delia radicum.
    'Springer Science and Business Media LLC', 2015
    Co-Authors: Kergunteuil Alan, Dugravot Sébastien, Van Dam, Nicole M., Danner Holger, Cortesero Anne-marie
    Abstract:

    International audienceVolatile Organic Compounds (VOCs) released by plants are involved in various orientation processes of herbivorous insects and consequently play a crucial role in their reproductive success. In the context of developing new strategies for crop protection, several studies have previously demonstrated the possibility to limit insect density on crops using either host or non-host plants that release attractive or repellent VOCs, respectively. The cabbage root fly, Delia radicum, is an important pest of brassicaceous crops for which control methods have to be implemented. Several studies have shown that plant odors influence cabbage root fly behavior, but only few VOCs have been identified so far. The present study aimed at selecting both plants and olfactory stimuli that could be used in the development of a "push-pull" strategy against the cabbage root fly. Olfactometer results revealed that plants belonging to the same family, even to the same species, may exhibit different levels of attractiveness toward D. radicum. Plants that were found attractive in behavioral observations were characterized by high release rates of distinct terpenes, such as linalool, β-caryophyllene, humulene, and α-farnesene. This study represents a first step to identify both attractive plants of agronomic interest, and additional volatiles that could be used in the context of trap crops to protect broccoli fields against the cabbage root fly

  • Crop protection with plant odors : behavioural maipulation of the cabbage root fly, Delia radicum, and natural enemies based on volatil organic compounds
    2013
    Co-Authors: Kergunteuil Alan
    Abstract:

    Les recherches menées au cours des dernières années ont permis de mettre en évidence les nombreuses fonctions écologiques des composés organiques volatils (COVs) émis par les plantes. Cette thèse a eu pour objectif d'utiliser ces connaissances dans un cadre de protection des cultures. Nous avons essayé de poser les bases d'une stratégie de type « Push-Pull » contre la mouche du chou (Delia radicum) en utilisant des sources d'odeurs synthétiques (diffuseurs de COVs) ou des sources d'odeurs naturelles (plantes compagnes). A partir d'observations menées en plein champ nous avons sélectionné plusieurs brassicacées présentant des taux d'infestations contrastés vis-à-vis de la mouche du chou. Des expérimentations de laboratoires combinant des études comportementales et des analyses chromatographiques ont permis (i) d'établir un lien entre l'infestation et l'attractivité de certaines plantes (ii) d'identifier de nouveaux COVs potentiellement impliqués dans les prises de décisions comportementales de D. radicum. En parallèle, des études de terrain ont permis de tester l'efficacité de diffuseurs de COVs synthétiques au sein de parcelles expérimentales, que ce soit (i) pour favoriser le recrutement d'ennemis naturels (ii) attirer (composante « Pull ») ou repousser (composante « Push ») la mouche du chou. Enfin, l'utilisation de plantes pièges concentrant le ravageur semble être intéressante pour modifier la répartition de la mouche du chou à l'échelle de la parcelle en vue de protéger des cultures d'intérêt telles que le brocoli.Volatile organic compounds (VOCs) emitted by plants are used by phytophagous, predatory and parasitoid insects to adjust behavioral decisions in complex environments. We aimed at using these ecological functions of VOCs in crop protection. We developed the first steps of a "Push-Pull" strategy toward the cabbage root fly (Delia radicum) with both dispensers of synthetic VOCs and natural blends of VOCs released by plants. We conducted a field study to select brassicaceous plants exhibiting contrasted levels of infestation toward the cabbage root fly. Laboratory bioassays combining behavioral observations and gas chromatographic analyses allowed to (i) investigate the relation between plant infestation and plant attractiveness (ii) identify novel VOCs involved in behavioral decisions of the cabbage root fly. Parallel field experiments were used to test the potential of dispensers of synthetic VOCs to (i) enhance natural enemies recruitment (ii) modify cabbage root fly behavior, attracting ("Pull" component) or repelling the pest ("Push" component). Finally, we demonstrated that attractive plants are promising for a trap crop approach enabling to redistribute cabbage root fly density at the field scale in order to protect main crop such as broccoli

  • Des odeurs pour protéger les cultures : utilisation de composés volatils pour modifier le comportement de la mouche du chou, Delia radicum et de ses ennemis naturels
    HAL CCSD, 2013
    Co-Authors: Kergunteuil Alan
    Abstract:

    Volatile organic compounds (VOCs) emitted by plants are used by phytophagous, predatory and parasitoid insects to adjust behavioral decisions in complex environments. We aimed at using these ecological functions of VOCs in crop protection. We developed the first steps of a "Push-Pull" strategy toward the cabbage root fly (Delia radicum) with both dispensers of synthetic VOCs and natural blends of VOCs released by plants. We conducted a field study to select brassicaceous plants exhibiting contrasted levels of infestation toward the cabbage root fly. Laboratory bioassays combining behavioral observations and gas chromatographic analyses allowed to (i) investigate the relation between plant infestation and plant attractiveness (ii) identify novel VOCs involved in behavioral decisions of the cabbage root fly. Parallel field experiments were used to test the potential of dispensers of synthetic VOCs to (i) enhance natural enemies recruitment (ii) modify cabbage root fly behavior, attracting ("Pull" component) or repelling the pest ("Push" component). Finally, we demonstrated that attractive plants are promising for a trap crop approach enabling to redistribute cabbage root fly density at the field scale in order to protect main crop such as broccoli.Les recherches menées au cours des dernières années ont permis de mettre en évidence les nombreuses fonctions écologiques des composés organiques volatils (COVs) émis par les plantes. Cette thèse a eu pour objectif d'utiliser ces connaissances dans un cadre de protection des cultures. Nous avons essayé de poser les bases d'une stratégie de type « Push-Pull » contre la mouche du chou (Delia radicum) en utilisant des sources d'odeurs synthétiques (diffuseurs de COVs) ou des sources d'odeurs naturelles (plantes compagnes). A partir d'observations menées en plein champ nous avons sélectionné plusieurs brassicacées présentant des taux d'infestations contrastés vis-à-vis de la mouche du chou. Des expérimentations de laboratoires combinant des études comportementales et des analyses chromatographiques ont permis (i) d'établir un lien entre l'infestation et l'attractivité de certaines plantes (ii) d'identifier de nouveaux COVs potentiellement impliqués dans les prises de décisions comportementales de D. radicum. En parallèle, des études de terrain ont permis de tester l'efficacité de diffuseurs de COVs synthétiques au sein de parcelles expérimentales, que ce soit (i) pour favoriser le recrutement d'ennemis naturels (ii) attirer (composante « Pull ») ou repousser (composante « Push ») la mouche du chou. Enfin, l'utilisation de plantes pièges concentrant le ravageur semble être intéressante pour modifier la répartition de la mouche du chou à l'échelle de la parcelle en vue de protéger des cultures d'intérêt telles que le brocoli

  • Des odeurs pour protéger les cultures (utilisation de composés volatils pour modifier le comportement de la mouche du chou, Delia radicum et de ses ennemis naturels)
    2013
    Co-Authors: Kergunteuil Alan, Cortesero Anne-marie, Dugravot, Marie Josèphe
    Abstract:

    Les recherches menées au cours des dernières années ont permis de mettre en évidence les nombreuses fonctions écologiques des composés organiques volatils (COVs) émis par les plantes. Cette thèse a eu pour objectif d'utiliser ces connaissances dans un cadre de protection des cultures. Nous avons essayé de poser les bases d'une stratégie de type Push-Pull contre la mouche du chou (Delia radicum) en utilisant des sources d'odeurs synthétiques (diffuseurs de COVs) ou des sources d'odeurs naturelles (plantes compagnes). A partir d'observations menées en plein champ nous avons sélectionné plusieurs brassicacées présentant des taux d'infestations contrastés vis-à-vis de la mouche du chou. Des expérimentations de laboratoires combinant des études comportementales et des analyses chromatographiques ont permis (i) d'établir un lien entre l'infestation et l'attractivité de certaines plantes (ii) d'identifier de nouveaux COVs potentiellement impliqués dans les prises de décisions comportementales de D. radicum. En parallèle, des études de terrain ont permis de tester l'efficacité de diffuseurs de COVs synthétiques au sein de parcelles expérimentales, que ce soit (i) pour favoriser le recrutement d'ennemis naturels (ii) attirer (composante Pull ) ou repousser (composante Push ) la mouche du chou. Enfin, l'utilisation de plantes pièges concentrant le ravageur semble être intéressante pour modifier la répartition de la mouche du chou à l'échelle de la parcelle en vue de protéger des cultures d'intérêt telles que le brocoli.Volatile organic compounds (VOCs) emitted by plants are used by phytophagous, predatory and parasitoid insects to adjust behavioral decisions in complex environments. We aimed at using these ecological functions of VOCs in crop protection. We developed the first steps of a "Push-Pull" strategy toward the cabbage root fly (Delia radicum) with both dispensers of synthetic VOCs and natural blends of VOCs released by plants. We conducted a field study to select brassicaceous plants exhibiting contrasted levels of infestation toward the cabbage root fly. Laboratory bioassays combining behavioral observations and gas chromatographic analyses allowed to (i) investigate the relation between plant infestation and plant attractiveness (ii) identify novel VOCs involved in behavioral decisions of the cabbage root fly. Parallel field experiments were used to test the potential of dispensers of synthetic VOCs to (i) enhance natural enemies recruitment (ii) modify cabbage root fly behavior, attracting ("Pull" component) or repelling the pest ("Push" component). Finally, we demonstrated that attractive plants are promising for a trap crop approach enabling to redistribute cabbage root fly density at the field scale in order to protect main crop such as broccoli.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF

Nicole M. Van Dam - One of the best experts on this subject based on the ideXlab platform.

  • For additional information about this publication click this link.
    2016
    Co-Authors: Nicole M. Van Dam, Devasena Samudrala, F J M Harren, Simona M Cristescu
    Abstract:

    Please be advised that this information was generated on 2016-05-13 and may be subject to change. Open access – Research article THIS ARTICLE IS PART OF A SPECIAL ISSUE ENTITLED ‘TRACE GAS BIOLOGY’ Real-time analysis of sulfur-containing volatiles in Brassica plants infested with root-feeding Delia radicum larvae using proton-transfer reaction mass spectrometr

  • Open access – Research article THIS ARTICLE IS PART OF A SPECIAL ISSUE ENTITLED ‘TRACE GAS BIOLOGY’
    2016
    Co-Authors: Nicole M. Van Dam, Devasena Samudrala, F J M Harren, Simona M Cristescu
    Abstract:

    Real-time analysis of sulfur-containing volatiles in Brassica plants infested with root-feeding Delia radicum larvae using proton-transfer reaction mass spectrometr

  • on line detection of root induced volatiles in brassica nigra plants infested with Delia radicum l root fly larvae
    Phytochemistry, 2012
    Co-Authors: E Crespo, Cornelis A Hordijk, Rob M De Graaf, Devasena Samudrala, Simona M Cristescu, F J M Harren, Nicole M. Van Dam
    Abstract:

    Abstract Plants emit various volatile organic compounds (VOCs) upon herbivore attack. These VOC emissions often show temporal dynamics which may influence the behavior of natural enemies using these volatiles as cues. This study analyzes on-line VOC emissions by roots of Brassica nigra plants under attack by cabbage root fly larvae, Delia radicum. Root emitted VOCs were detected using Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) and Gas Chromatography–Mass Spectrometry (GC–MS). These analyses showed that several sulfur containing compounds, such as methanethiol, dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and glucosinolate breakdown products, such as thiocyanates (TC) and isothiocyanates (ITC), were emitted by the roots in response to infestation. The emissions were subdivided into early responses, emerging within 1–6 h after infestation, and late responses, evolving only after 6–12 h. The marker for rapid responses was detected at m / z 60. The ion detected at m / z 60 was identified as thiocyanic acid, which is also a prominent fragment in some TC or ITC spectra. The emission of m / z 60 stopped when the larvae had pupated, which makes it an excellent indicator for actively feeding larvae. Methanethiol, DMS and DMDS levels increased much later in infested roots, indicating that activation of enzymes or genes involved in the production of these compounds may be required. Earlier studies have shown that both early and late responses can play a role in tritrophic interactions associated with Brassica species. Moreover, the identification of these root induced responses will help to design non-invasive analytical procedures to assess root infestations.

  • broccoli and turnip plants display contrasting responses to belowground induction by Delia radicum infestation and phytohormone applications
    Phytochemistry, 2012
    Co-Authors: Prisca S Pierre, Sébastien Dugravot, Anne-marie Cortesero, Denis Poinsot, Ciska E. Raaijmakers, Hany M. Hassan, Nicole M. Van Dam
    Abstract:

    Abstract Induced responses to insect herbivory are a common phenomenon in the plant kingdom. So far, induced responses have mostly investigated in aerial plant parts. Recently it was found that root herbivore may also elicit both local and systemic responses affecting aboveground herbivores and their natural enemies. Using broccoli ( Brassica oleracea subsp. italica L.) and turnip ( Brassica rapa subsp. rapa L.), two cultivated brassicaceaous plants differing in their chemistry and morphology, we analysed the local and systemic induced responses triggered by Delia radicum L. damage, JA and SA application. We also assessed whether the root induction treatments affected D. radicum larval performance. Both D. radicum damage and JA induced changes in glucosinolate and sugar content as well as affected D. radicum performance, while SA application did not. Despite the uniform chemical responses, the effect on larval performance on broccoli and turnip plants was very different. On broccoli, JA root treatment reduced herbivore performance, whereas in turnips the same treatment enhanced it. JA- and D. radicum -induced responses followed similar patterns, which suggests that the JA signalling pathway is involved in root-induced responses to larval feeding. Glucosinolate induction cannot fully explain the differences found in the performance of D. radicum on the different species. Changes in other resistance factors might significantly contribute to the induced resistance in these brassicaceaeous species as well.

  • real time analysis of sulfur containing volatiles in brassica plants infested with root feeding Delia radicum larvae using proton transfer reaction mass spectrometry
    Aob Plants, 2012
    Co-Authors: Nicole M. Van Dam, Devasena Samudrala, F J M Harren, Simona M Cristescu
    Abstract:

    BACKGROUND AND AIMS Plants damaged by herbivores emit a variety of volatile organic compounds (VOCs). Here we used proton-transfer reaction mass spectrometry (PTR-MS) as a sensitive detection method for online analysis of herbivore-induced VOCs. Previously, it was found that Brassica nigra plants emit several sulfur-containing VOCs when attacked by cabbage root fly (Delia radicum) larvae with m/z 60 as a marker for the formation of allylisothiocyanate from the glucosinolate sinigrin. We tested the hypothesis that m/z 60 emission occurs only in plants with sinigrin in their roots. Additionally, we tested the hypothesis that methanethiol, dimethylsulfide and dimethyldisulfide are only emitted after larval infestation. METHODOLOGY Proton-transfer reaction mass spectrometry was used to track sulfur-containing VOCs from six different species of Brassica over time. The roots were either artificially damaged or infested with cabbage root fly larvae. Glucosinolate profiles of the roots were analysed using high-pressure liquid chromatography and compared with VOC emissions. PRINCIPAL RESULTS Brassica nigra, B. juncea and B. napus primarily emitted m/z 60 directly after artificial damage or root fly infestation. Sulfide and methanethiol emissions from B. nigra and B. juncea also increased after larval damage but much later (6-12 h after damage). Brassica rapa, B. oleracea and B. carinata principally emitted methanethiol after artificial and after larval damage. Brassica oleracea and B. carinata showed some increase in m/z 60 emission after larval damage. Comparison with root glucosinolate profiles revealed that sinigrin cannot be the only precursor for m/z 60. CONCLUSIONS The principal compound emitted after root damage is determined by the plant species, and not by damage type or root glucosinolate composition. Once determined, the principal compounds may be used as markers for identifying damaged or infested plants. Further analyses of plant enzymes involved in the breakdown of sulfur compounds is needed to reveal the origin of sulfur-containing VOCs from plants.