Jürgen Gross - Academia.edu (original) (raw)

Papers by Jürgen Gross

Journal of Pest Science, 2008

Research on Chrysomelidae, Volume 2, 2009

Journal of Pest Science, 2006

ABSTRACT

Recent Advances in Phytochemistry

The results obtained by the analysis of functions and structures of plant, insect, and microbe me... more The results obtained by the analysis of functions and structures of plant, insect, and microbe metabolites in interactions among each other and with their environment in natural settings hold a strong potential for developing new applications in plant protection or even human medicine. By identification and synthesis of chemical compounds responsible, e.g., for the regulation of migration between insects’ different host plants, we can gain access to important natural sources for the development of effective strategies using attractive and/or repellent molecules for biotechnical control of plant pests in the context of sustainable agricultural production. In addition, newly detected insect-born infochemicals, which have antifungal or antibacterial activity, bear a potential for the development of new active ingredients for medical purpose.

During the last few years my coworkers and me started to elucidate the chemical ecology of jumpin... more During the last few years my coworkers and me started to elucidate the chemical ecology of jumping plant lice (Hemiptera: Psyllidae) and their interactions with vectored phytoplasma and different host plants. We investigated the olfactory reactions of these insects to host plants used for reproduction or overwintering, and elucidated chemically mediated interactions between all players in this multitrophic system. While e.g. the behaviour of the hawthorn psyllid C. melanoneura was not influenced by phytoplasmas, complex interactions between Malus domestica, the apple psyllid C. picta, and Ca. P. mali were investigated in laboratory and field. Results from Y-tube olfactometer trials showed that immature adults of C. picta are able to distinguish the odours of healthy and infected apple trees and preferred the odour of infected trees. GC-MS analysis of the headspaces revealed the induction of a sesquiterpene in infected trees, which was proofed to be attractive for C. picta in olfacto...

Journal of Pest Science, 2006

... science. This includes advances in the control of primary pests (Sengonca et al. 2005) and ve... more ... science. This includes advances in the control of primary pests (Sengonca et al. 2005) and vectors of microbial diseases (Basky and Alma´si 2005), the targeted use of beneficial insects in pest control (Al-Zyoud et al. 2005) as ...

Oikos, 2004

. The significance of bottom-up effects for host plant specialization in Chrysomela leaf beetles.... more . The significance of bottom-up effects for host plant specialization in Chrysomela leaf beetles. Á/ Oikos 105: 368 Á/376. The leaf beetle species Chrysomela lapponica, which belongs to the so-called C. interrupta group, forms distinct allopatric populations either on willows (Salicaceae) or birches (Betulaceae). It was recently suggested that, on several occasions, host plant shifts from Salicaceae to Betulaceae occurred independently within the C. interrupta group. Our study aims to elucidate bottom-up effects of the host plants that might have shaped the evolution of host plant specialization in the populations of C. lapponica, and thus, to shed some light on the driving forces of host shifts within the C. interrupta group, too. We compared the oviposition behaviour and performance of two C. lapponica populations, one of which has adapted to birches and the other to willows. The studies were conducted under laboratory conditions, eliminating the impact of natural enemies. Experiments involving the transfer of individuals of the birchspecialized population to willows and vice versa with individuals of the willowspecialized population to birches aimed to examine the plasticity in host plant use. Females of each population almost exclusively chose their natural host plant for oviposition, when offering birch and willow in dual choice experiments. When specimens of the two C. lapponica populations were reared on their natural host plants, the birch specialists suffered higher mortality, needed a longer period of development and produced less larval defensive secretion than the willow specialists. When the birch specialists were fed with willow, these performance parameters decreased even more. Other parameters, such as body weight and fecundity, did not differ between birch and willow specialists when they were fed with their natural host plant. While individuals of the birch-specialized population could be reared on willow, all neonate larvae from the willow-specialized population died after being transferred to birch. The significance of these bottom-up effects for the evolution of host plant specialization in C. lapponica is discussed. Approximately 400,000 species, representing nearly half of all known recent insect species, feed on green plants. A very striking feature of insect herbivory is the fact that most species are specialists, i.e. they feed on one or a few closely related host plant species . Several factors ranging from ecological forces to physiological and genetic ones have been considered to drive host plant specialization (Denno et

Journal of Pest Science, 2007

The Palaearctic leaf beetle Chrysomela lapponica usually feeds upon willows in the northern regio... more The Palaearctic leaf beetle Chrysomela lapponica usually feeds upon willows in the northern region of its occurrence. However, in Central Europe, some populations are known that have specialised on birch. In this study, we investigated the signiWcance of other herbivores occurring together on the same host plants as possible exploitative competitors of C. lapponica. Two populations were studied: a population from Finland specialised on the willow Salix borealis, and a population from the Czech Republic, specialised on the birch Betula pubescens. Abundances of folivorous and suctivorous insects on both host plants were recorded at both population sites. The willow leaf beetle Phratora vitellinae was the most abundant herbivorous insect at both study sites on willow. A Weld study was conducted to examine the eVects of P. vitellinae on the performance of C. lapponica. The presence of P. vitellinae larvae on the same twig upon which C. lapponica larvae were feeding did not aVect increase of body weight in C. lapponica larvae. Thus, the high resource availability of both willows and birches suggest that interspeciWc competition is unlikely to be a selection factor driving the evolution of host shift in C. lapponica.

Ecological Entomology, 2004

1. The Salicaceae have been suggested as ancestral host plants of Chrysomela species (Coleoptera:... more 1. The Salicaceae have been suggested as ancestral host plants of Chrysomela species (Coleoptera: Chrysomelidae). In Chrysomela lapponica, some populations are specialised on salicaceous plants, but others have switched to birch. This study aimed to elucidate the significance of natural enemies as possible selective forces for the host plant shift of C. lapponica from willow to birch.

Vitis -Geilweilerhof-

The Asian ladybird beetles Harmonia axyridis feed on damaged fruits in late summer and in autumn,... more The Asian ladybird beetles Harmonia axyridis feed on damaged fruits in late summer and in autumn, especially on grapes. By getting harvested and processed together with the grapes, they cause an off-flavor in the wine, the so-called "ladybird taint" (LBT). Depending on fermentation conditions of red wine variety 'Pinot Noir', panelists recognized the LBT at different concentrations: Fewer beetles were required in the nonheated treatment to elicit LBT. The sensory detection threshold for LBT in must fermented wines was about 3 beetles·kg-1 of grapes and in must heated wines it was about 6 beetles·kg-1 of grapes. In the white wine variety 'Riesling', the sensory detection threshold for LBT was at 4 beetles·kg-1 of grapes. The main olfactory active compound causing LBT, 2-isopropyl-3-methoxypyrazine (IPMP), was detected by 50 % of panelists at a threshold of 1 ng·L-1 in 'Riesling' and 2 ng·L-1 in 'Pinot noir'. Thus, a threshold of five beetles ...

Drosophila suzukii: a new threat for European fruit crops and viticulture. Die invasive Kirschess... more Drosophila suzukii: a new threat for European fruit crops and viticulture. Die invasive Kirschessigfliege Drosophila suzukii ist innerhalb kurzer Zeit zu einer enormen Bedrohung für den europäischen Obst- und Weinbau geworden. Die Art gehört zu den Obst-, Essig- oder Taufliegen (Diptera: Drosophilidae) und stammt ursprünglich aus Asien. Sie befällt im Gegensatz zu anderen Arten derselben Gattung gesunde Früchte und verfügt über ein sehr breites Wirtspflanzenspektrum. Die hohe Vermehrungsrate, der kurze Entwicklungszyklus, das beträchtliche Ausbreitungspotential und das hohe Risiko der Verschleppung machen die Kirschessigfliege in den „eroberten“ Gebieten sehr rasch zu einem Hauptschädling, vor allem im Stein- und Beerenobst sowie Trauben.

Microbiological Research, 2015

Please cite this article in press as: Geider K, et al. Unifying bacteria from decaying wood with ... more Please cite this article in press as: Geider K, et al. Unifying bacteria from decaying wood with various ubiquitous Gibbsiella species as G. acetica sp. nov. based on nucleotide sequence similarities and their acetic acid secretion. Microbiol Res (2015), http://dx.

Methods in molecular biology (Clifton, N.J.), 2013

Insect vectors of phytoplasmas are limited to leafhoppers, planthoppers, and psyllids. While popu... more Insect vectors of phytoplasmas are limited to leafhoppers, planthoppers, and psyllids. While populations can be monitored by a number of passive techniques in the field, the capture of live insects is necessary for manipulation and study. A number of physical methods for capturing these insects already exist, but more innovative traps equipped with infochemical lures for species-specific monitoring and mass trapping are being developed.

Phytopathogenic Mollicutes, 2013

Candidatus Phytopalsma mali' directly manipulates plant physiology and indirectly vector behaviou... more Candidatus Phytopalsma mali' directly manipulates plant physiology and indirectly vector behaviour by attracting its vector Cacopsylla picta to infected plants and thus increasing its spread within the host plant population. In recent years constructing traps with attractive components like β-caryophyllene for the capture of psyllids could greatly reduce the efforts necessary for insect identification. Furthermore, through this monitoring the amount of chemical insecticides can be reduced by detecting the adequate date for spraying. Because the infochemical produced by infected plants is attractive to both sexes of psyllids, it could also be possible to develop mass trapping systems for a sustainable control of these insects. When identified, attractive compounds could be used in traps as lures for monitoring and mass trapping purposes and combined with repellent compounds these chemicals can be used in complex push-and-pull strategies.

Journal of Pest Science, 2008

Research on Chrysomelidae, Volume 2, 2009

Journal of Pest Science, 2006

ABSTRACT

Recent Advances in Phytochemistry

The results obtained by the analysis of functions and structures of plant, insect, and microbe me... more The results obtained by the analysis of functions and structures of plant, insect, and microbe metabolites in interactions among each other and with their environment in natural settings hold a strong potential for developing new applications in plant protection or even human medicine. By identification and synthesis of chemical compounds responsible, e.g., for the regulation of migration between insects’ different host plants, we can gain access to important natural sources for the development of effective strategies using attractive and/or repellent molecules for biotechnical control of plant pests in the context of sustainable agricultural production. In addition, newly detected insect-born infochemicals, which have antifungal or antibacterial activity, bear a potential for the development of new active ingredients for medical purpose.

During the last few years my coworkers and me started to elucidate the chemical ecology of jumpin... more During the last few years my coworkers and me started to elucidate the chemical ecology of jumping plant lice (Hemiptera: Psyllidae) and their interactions with vectored phytoplasma and different host plants. We investigated the olfactory reactions of these insects to host plants used for reproduction or overwintering, and elucidated chemically mediated interactions between all players in this multitrophic system. While e.g. the behaviour of the hawthorn psyllid C. melanoneura was not influenced by phytoplasmas, complex interactions between Malus domestica, the apple psyllid C. picta, and Ca. P. mali were investigated in laboratory and field. Results from Y-tube olfactometer trials showed that immature adults of C. picta are able to distinguish the odours of healthy and infected apple trees and preferred the odour of infected trees. GC-MS analysis of the headspaces revealed the induction of a sesquiterpene in infected trees, which was proofed to be attractive for C. picta in olfacto...

Journal of Pest Science, 2006

... science. This includes advances in the control of primary pests (Sengonca et al. 2005) and ve... more ... science. This includes advances in the control of primary pests (Sengonca et al. 2005) and vectors of microbial diseases (Basky and Alma´si 2005), the targeted use of beneficial insects in pest control (Al-Zyoud et al. 2005) as ...

Oikos, 2004

. The significance of bottom-up effects for host plant specialization in Chrysomela leaf beetles.... more . The significance of bottom-up effects for host plant specialization in Chrysomela leaf beetles. Á/ Oikos 105: 368 Á/376. The leaf beetle species Chrysomela lapponica, which belongs to the so-called C. interrupta group, forms distinct allopatric populations either on willows (Salicaceae) or birches (Betulaceae). It was recently suggested that, on several occasions, host plant shifts from Salicaceae to Betulaceae occurred independently within the C. interrupta group. Our study aims to elucidate bottom-up effects of the host plants that might have shaped the evolution of host plant specialization in the populations of C. lapponica, and thus, to shed some light on the driving forces of host shifts within the C. interrupta group, too. We compared the oviposition behaviour and performance of two C. lapponica populations, one of which has adapted to birches and the other to willows. The studies were conducted under laboratory conditions, eliminating the impact of natural enemies. Experiments involving the transfer of individuals of the birchspecialized population to willows and vice versa with individuals of the willowspecialized population to birches aimed to examine the plasticity in host plant use. Females of each population almost exclusively chose their natural host plant for oviposition, when offering birch and willow in dual choice experiments. When specimens of the two C. lapponica populations were reared on their natural host plants, the birch specialists suffered higher mortality, needed a longer period of development and produced less larval defensive secretion than the willow specialists. When the birch specialists were fed with willow, these performance parameters decreased even more. Other parameters, such as body weight and fecundity, did not differ between birch and willow specialists when they were fed with their natural host plant. While individuals of the birch-specialized population could be reared on willow, all neonate larvae from the willow-specialized population died after being transferred to birch. The significance of these bottom-up effects for the evolution of host plant specialization in C. lapponica is discussed. Approximately 400,000 species, representing nearly half of all known recent insect species, feed on green plants. A very striking feature of insect herbivory is the fact that most species are specialists, i.e. they feed on one or a few closely related host plant species . Several factors ranging from ecological forces to physiological and genetic ones have been considered to drive host plant specialization (Denno et

Journal of Pest Science, 2007

The Palaearctic leaf beetle Chrysomela lapponica usually feeds upon willows in the northern regio... more The Palaearctic leaf beetle Chrysomela lapponica usually feeds upon willows in the northern region of its occurrence. However, in Central Europe, some populations are known that have specialised on birch. In this study, we investigated the signiWcance of other herbivores occurring together on the same host plants as possible exploitative competitors of C. lapponica. Two populations were studied: a population from Finland specialised on the willow Salix borealis, and a population from the Czech Republic, specialised on the birch Betula pubescens. Abundances of folivorous and suctivorous insects on both host plants were recorded at both population sites. The willow leaf beetle Phratora vitellinae was the most abundant herbivorous insect at both study sites on willow. A Weld study was conducted to examine the eVects of P. vitellinae on the performance of C. lapponica. The presence of P. vitellinae larvae on the same twig upon which C. lapponica larvae were feeding did not aVect increase of body weight in C. lapponica larvae. Thus, the high resource availability of both willows and birches suggest that interspeciWc competition is unlikely to be a selection factor driving the evolution of host shift in C. lapponica.

Ecological Entomology, 2004

1. The Salicaceae have been suggested as ancestral host plants of Chrysomela species (Coleoptera:... more 1. The Salicaceae have been suggested as ancestral host plants of Chrysomela species (Coleoptera: Chrysomelidae). In Chrysomela lapponica, some populations are specialised on salicaceous plants, but others have switched to birch. This study aimed to elucidate the significance of natural enemies as possible selective forces for the host plant shift of C. lapponica from willow to birch.

Vitis -Geilweilerhof-

The Asian ladybird beetles Harmonia axyridis feed on damaged fruits in late summer and in autumn,... more The Asian ladybird beetles Harmonia axyridis feed on damaged fruits in late summer and in autumn, especially on grapes. By getting harvested and processed together with the grapes, they cause an off-flavor in the wine, the so-called "ladybird taint" (LBT). Depending on fermentation conditions of red wine variety 'Pinot Noir', panelists recognized the LBT at different concentrations: Fewer beetles were required in the nonheated treatment to elicit LBT. The sensory detection threshold for LBT in must fermented wines was about 3 beetles·kg-1 of grapes and in must heated wines it was about 6 beetles·kg-1 of grapes. In the white wine variety 'Riesling', the sensory detection threshold for LBT was at 4 beetles·kg-1 of grapes. The main olfactory active compound causing LBT, 2-isopropyl-3-methoxypyrazine (IPMP), was detected by 50 % of panelists at a threshold of 1 ng·L-1 in 'Riesling' and 2 ng·L-1 in 'Pinot noir'. Thus, a threshold of five beetles ...

Drosophila suzukii: a new threat for European fruit crops and viticulture. Die invasive Kirschess... more Drosophila suzukii: a new threat for European fruit crops and viticulture. Die invasive Kirschessigfliege Drosophila suzukii ist innerhalb kurzer Zeit zu einer enormen Bedrohung für den europäischen Obst- und Weinbau geworden. Die Art gehört zu den Obst-, Essig- oder Taufliegen (Diptera: Drosophilidae) und stammt ursprünglich aus Asien. Sie befällt im Gegensatz zu anderen Arten derselben Gattung gesunde Früchte und verfügt über ein sehr breites Wirtspflanzenspektrum. Die hohe Vermehrungsrate, der kurze Entwicklungszyklus, das beträchtliche Ausbreitungspotential und das hohe Risiko der Verschleppung machen die Kirschessigfliege in den „eroberten“ Gebieten sehr rasch zu einem Hauptschädling, vor allem im Stein- und Beerenobst sowie Trauben.

Microbiological Research, 2015

Please cite this article in press as: Geider K, et al. Unifying bacteria from decaying wood with ... more Please cite this article in press as: Geider K, et al. Unifying bacteria from decaying wood with various ubiquitous Gibbsiella species as G. acetica sp. nov. based on nucleotide sequence similarities and their acetic acid secretion. Microbiol Res (2015), http://dx.

Methods in molecular biology (Clifton, N.J.), 2013

Insect vectors of phytoplasmas are limited to leafhoppers, planthoppers, and psyllids. While popu... more Insect vectors of phytoplasmas are limited to leafhoppers, planthoppers, and psyllids. While populations can be monitored by a number of passive techniques in the field, the capture of live insects is necessary for manipulation and study. A number of physical methods for capturing these insects already exist, but more innovative traps equipped with infochemical lures for species-specific monitoring and mass trapping are being developed.

Phytopathogenic Mollicutes, 2013

Candidatus Phytopalsma mali' directly manipulates plant physiology and indirectly vector behaviou... more Candidatus Phytopalsma mali' directly manipulates plant physiology and indirectly vector behaviour by attracting its vector Cacopsylla picta to infected plants and thus increasing its spread within the host plant population. In recent years constructing traps with attractive components like β-caryophyllene for the capture of psyllids could greatly reduce the efforts necessary for insect identification. Furthermore, through this monitoring the amount of chemical insecticides can be reduced by detecting the adequate date for spraying. Because the infochemical produced by infected plants is attractive to both sexes of psyllids, it could also be possible to develop mass trapping systems for a sustainable control of these insects. When identified, attractive compounds could be used in traps as lures for monitoring and mass trapping purposes and combined with repellent compounds these chemicals can be used in complex push-and-pull strategies.