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Flavie Vanlerberghemasutti - One of the best experts on this subject based on the ideXlab platform.
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insight into the durability of plant resistance to aphids from a demo genetic study of Aphis gossypii in melon crops
Evolutionary Applications, 2016Co-Authors: Sophie Thomas, Flavie Vanlerberghemasutti, P Mistral, Anne Loiseau, Nathalie BoissotAbstract:Resistance breakdown has been observed following the deployment of plant cultivars resistant to pests. Assessing the durability of a resistance requires long‐term experiments at least at a regional scale. We collected such data for melon resistance conferred by the Vat gene cluster to melon aphids. We examined landscape‐level populations of Aphis gossypii collected in 2004–2015, from melon‐producing regions with and without the deployment of Vat resistance and with different climates. We conducted demo‐genetic analyses of the aphid populations on Vat and non‐Vat plants during the cropping seasons. The Vat resistance decreased the density of aphid populations in all areas and changed the genetic structure and composition of these populations. Two bottlenecks were identified in the dynamics of adapted clones, due to the low levels of production of dispersal morphs and winter extinction. Our results suggest that (i) Vat resistance will not be durable in the Lesser Antilles, where no bottleneck affected the dynamics of adapted clones, (ii) Vat resistance will be durable in south‐west France, where both bottlenecks affected the dynamics of adapted clones and (iii) Vat resistance will be less durable in south‐east France, where only one of the two bottlenecks was observed.
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dna based discrimination between the sibling species Aphis gossypii glover and Aphis frangulae kaltenbach
Systematic Entomology, 2009Co-Authors: Jerome Carletto, Aurelie Blin, Flavie VanlerberghemasuttiAbstract:Morphologically similar species occur in various groups of insects, including aphid pests. In Europe, Aphis frangulae Kaltenbach and Aphis gossypii Glover (sometimes considered as subspecies) are differentiated usually on the basis of life cycle and host plant. We used a sexual population of A. frangulae collected on the primary host and samples of A. gossypii collected on cucurbits or cotton for the development of molecular markers. DNA sequence data for the gene encoding cytochrome b and for the barcode region of cytochrome oxidase I, as well as a length polymorphism for an intron in the sodium channel para-type gene discriminated unambiguously between the two taxa. These markers were also used as identification keys for aphids collected on crops belonging to the Solanaceae. The cytochrome b marker differentiates host-related Aphis gossypii haplotypes, and the para-type gene intron might be suitable for the resolution of taxonomic problems in other aphid species complexes.
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genetic diversity of the cotton aphid Aphis gossypii in the unstable environment of a cotton growing area
Agricultural and Forest Entomology, 2008Co-Authors: Thierry Brevault, Jerome Carletto, Daphne Linderme, Flavie VanlerberghemasuttiAbstract:1 Spatial and temporal habitat heterogeneity represented by annual crops is a major factor influencing population dynamics of phytophagous insect pests such as the cotton aphid Aphis gossypii Glover. We studied the effects of instability of the cotton agroecosystem resulting from the temporary availability of the plant resource and the repeated use of insecticides on the genetic variability of the cotton aphids. 2 Samples of A. gossypii were collected in cotton plots, treated or not with insecticides and from vegetable crops (Malvaceae, Cucurbitaceae and Solanaceae) within the cotton growing area of northern Cameroon. The genetic structure of the samples was assessed using eight microsatellite markers. Insecticide resistance was estimated through the detection of two mutations in the ace-1 gene that are associated with insensitivity of acetylcholinesterase to carbamate and organophosphate insecticides. 3 The results obtained show that both host plants and insecticides act in genetic structuring of A. gossypii. Ninety-three percent of aphids collected on cotton were characterized by the same microsatellite multilocus genotype, Burk1, which also displays the insecticide resistant alleles. 4 During the dry season, the cotton crop season after, the genotype Burk1 was principally found on two other malvaceous cultivated plants, rosella and okra, acting as suitable reservoir plants. The ability of the cotton aphid to move among asynchronous suitable habitats in response to changes in resource availability enables the pest to exploit unstable cropping systems. An understanding of the cotton aphid life system may aid to improve strategies for integrated resistance management.
George E Heimpel - One of the best experts on this subject based on the ideXlab platform.
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worldwide populations of the aphid Aphis craccivora are infected with diverse facultative bacterial symbionts
Microbial Ecology, 2014Co-Authors: Cristina M Brady, Nicolas Desneux, Mark K Asplen, George E Heimpel, Keith R Hopper, Catherine R Linnen, Kerry M Oliver, Jason A Wulff, Jennifer A WhiteAbstract:Facultative bacterial endosymbionts can play an important role in the evolutionary trajectory of their hosts. Aphids (Hemiptera: Aphididae) are infected with a wide variety of facultative endosymbionts that can confer ecologically relevant traits, which in turn may drive microevolutionary processes in a dynamic selective environment. However, relatively little is known about how symbiont diversity is structured in most aphid species. Here, we investigate facultative symbiont species richness and prevalence among worldwide populations of the cowpea aphid, Aphis craccivora Koch. We surveyed 44 populations of A. craccivora, and detected 11 strains of facultative symbiotic bacteria, representing six genera. There were two significant associations between facultative symbiont and aphid food plant: the symbiont Arsenophonus was found at high prevalence in A. craccivora populations collected from Robinia sp. (locust), whereas the symbiont Hamiltonella was almost exclusively found in A. craccivora populations from Medicago sativa (alfalfa). Aphids collected from these two food plants also had divergent mitochondrial haplotypes, potentially indicating the formation of specialized aphid lineages associated with food plant (host-associated differentiation). The role of facultative symbionts in this process remains to be determined. Overall, observed facultative symbiont prevalence in A. craccivora was lower than that of some other well-studied aphids (e.g., Aphis fabae and Acyrthosiphon pisum), possibly as a consequence of A. craccivora's almost purely parthenogenetic life history. Finally, most (70 %) of the surveyed populations were polymorphic for facultative symbiont infection, indicating that even when symbiont prevalence is relatively low, symbiont-associated phenotypic variation may allow population-level evolutionary responses to local selection.
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the endosymbiont arsenophonus is widespread in soybean aphid Aphis glycines but does not provide protection from parasitoids or a fungal pathogen
PLOS ONE, 2013Co-Authors: Jason A Wulff, George E Heimpel, Kongming Wu, Karrie A Buckman, Jennifer A WhiteAbstract:Aphids commonly harbor bacterial facultative symbionts that have a variety of effects upon their aphid hosts, including defense against hymenopteran parasitoids and fungal pathogens. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is infected with the symbiont Arsenophonus sp., which has an unknown role in its aphid host. Our research goals were to document the infection frequency and diversity of the symbiont in field-collected soybean aphids, and to determine whether Arsenophonus is defending soybean aphid against natural enemies. We performed diagnostic PCR and sequenced four Arsenophonus genes in soybean aphids from their native and introduced range to estimate infection frequency and genetic diversity, and found that Arsenophonus infection is highly prevalent and genetically uniform. To evaluate the defensive role of Arsenophonus, we cured two aphid genotypes of their natural Arsenophonus infection through ampicillin microinjection, resulting in infected and uninfected isolines within the same genetic background. These isolines were subjected to parasitoid assays using a recently introduced biological control agent, Binodoxys communis [Braconidae], a naturally recruited parasitoid, Aphelinus certus [Aphelinidae], and a commercially available biological control agent, Aphidius colemani [Braconidae]. We also assayed the effect of the common aphid fungal pathogen, Pandora neoaphidis (Remaudiere & Hennebert) Humber (Entomophthorales: Entomophthoraceae), on the same aphid isolines. We did not find differences in successful parasitism for any of the parasitoid species, nor did we find differences in P. neoaphidis infection between our treatments. Our conclusion is that Arsenophonus does not defend its soybean aphid host against these major parasitoid and fungal natural enemies.
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parasitism of the soybean aphid Aphis glycines by binodoxys communis the role of aphid defensive behaviour and parasitoid reproductive performance
Bulletin of Entomological Research, 2008Co-Authors: Kris A G Wyckhuys, Nicolas Desneux, Keith R Hopper, Laura Hocum L Stone, Kim A Hoelmer, George E HeimpelAbstract:The Asian parasitoid, Binodoxys communis (Gahan) (Hymenoptera: Braconidae), is a candidate for release against the exotic soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in North America. In this study, we examined preferences by B. communis for the different developmental stages of A. glycines and investigated consequences of these preferences for parasitoid fitness. We also determined to what extent aphid defensive behaviours mediate such preferences. We found that B. communis readily attacks and successfully develops in the different A. glycines developmental stages. Binodoxys communis development time gradually increased with aphid developmental stage, and wasps took longest to develop in alates. An average (±SE) of 54.01±0.08% of parasitized A. glycines alatoid nymphs transformed into winged adult aphids prior to mummification. No-choice assays showed a higher proportion of successful attacks for immature apterous A. glycines nymphs compared to adults and alatoid nymphs. Also, choice trials indicated avoidance and lower attack and oviposition of adults and alatoid nymphs. The different aphid stages exhibited a range of defensive behaviours, including body raising, kicking and body rotation. These defenses were employed most effectively by larger aphids. We discuss implications for the potential establishment, spread and biological control efficacy of A. glycines by B. communis in the event that it is released in North America.
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flight performance of the soybean aphid Aphis glycines hemiptera aphididae under different temperature and humidity regimens
Environmental Entomology, 2008Co-Authors: Ying Zhang, Kris A G Wyckhuys, Kongming Wu, Limin Wang, George E HeimpelAbstract:The soybean aphid, Aphis glycines (Matsumura), is native to eastern Asia and has recently invaded North America, where it is currently the most important insect pest of soybeans. The soybean aphid has spread rapidly within North America, presumably through a combination of active and passive (wind-aided) flight. Here, we studied the active flight potential of A. glycines under a range of environmental conditions using an aphid flight mill. Winged (alate) A. glycines were tested on a specially designed 32-channel, computer-monitored flight mill system. Aphids that were 12–24 h old exhibited the strongest flight behavior, with average flight durations of 3.3–4.1 h, which represented flight distances of 4.6–5.1 km. After the age of 72 h, A. glycines flight performance rapidly declined. The optimum temperature range for flight was 16–28°C, whereas optimum relative humidity was 75%. Our findings show that A. glycines posseses a fairly strong active flight aptitude (ability and inclination) and point to the possibility of flight initiation under a broad range of environmental conditions. These results have the potential to aid forecasting and management protocols for A. glycines at the landscape level.
Nicolas Desneux - One of the best experts on this subject based on the ideXlab platform.
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sublethal and hormesis effects of imidacloprid on the soybean aphid Aphis glycines
Ecotoxicology, 2015Co-Authors: Yanyan Qu, Nicolas Desneux, Da Xiao, Jinyu Li, Zhou Chen, Antonio Biondi, Dunlun SongAbstract:The soybean aphid, Aphis glycines Matsumura, is a major pest in soybean crop. Current management of this pest relies mainly on insecticides applications, and the neonicotinoid imidacloprid has been proposed as an effective insecticide to control A. glycines in soybean field. Imidacloprid at lethal concentrations not only exerts acute toxicity to A. glycines, but also cause various biological changes when aphids are chronically exposed to lower concentrations. In this study, we assessed the effects of a low-lethal (0.20 mg L−1) and two sublethal (0.05 and 0.10 mg L−1) imidacloprid concentrations on various A. glycines life history traits. Aphid exposure to 0.20 mg L−1 imidacloprid caused slower juvenile development, shorter reproductive period, and reduced adult longevity, fecundity and total lifespan. Stimulatory effects, i.e. hormesis, on reproduction and immature development duration were observed in aphids exposed to the lower sublethal imidacloprid concentrations. Consequently, the net reproduction rate (R 0) was significantly higher than in the control aphids. These findings stress the importance of the actual imidacloprid concentration in its toxicological properties on A. glycines. Therefore, our results would be useful for assessing the overall effects of imidacloprid on A. glycines and for optimizing integrated pest management programs targeting this pest.
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worldwide populations of the aphid Aphis craccivora are infected with diverse facultative bacterial symbionts
Microbial Ecology, 2014Co-Authors: Cristina M Brady, Nicolas Desneux, Mark K Asplen, George E Heimpel, Keith R Hopper, Catherine R Linnen, Kerry M Oliver, Jason A Wulff, Jennifer A WhiteAbstract:Facultative bacterial endosymbionts can play an important role in the evolutionary trajectory of their hosts. Aphids (Hemiptera: Aphididae) are infected with a wide variety of facultative endosymbionts that can confer ecologically relevant traits, which in turn may drive microevolutionary processes in a dynamic selective environment. However, relatively little is known about how symbiont diversity is structured in most aphid species. Here, we investigate facultative symbiont species richness and prevalence among worldwide populations of the cowpea aphid, Aphis craccivora Koch. We surveyed 44 populations of A. craccivora, and detected 11 strains of facultative symbiotic bacteria, representing six genera. There were two significant associations between facultative symbiont and aphid food plant: the symbiont Arsenophonus was found at high prevalence in A. craccivora populations collected from Robinia sp. (locust), whereas the symbiont Hamiltonella was almost exclusively found in A. craccivora populations from Medicago sativa (alfalfa). Aphids collected from these two food plants also had divergent mitochondrial haplotypes, potentially indicating the formation of specialized aphid lineages associated with food plant (host-associated differentiation). The role of facultative symbionts in this process remains to be determined. Overall, observed facultative symbiont prevalence in A. craccivora was lower than that of some other well-studied aphids (e.g., Aphis fabae and Acyrthosiphon pisum), possibly as a consequence of A. craccivora's almost purely parthenogenetic life history. Finally, most (70 %) of the surveyed populations were polymorphic for facultative symbiont infection, indicating that even when symbiont prevalence is relatively low, symbiont-associated phenotypic variation may allow population-level evolutionary responses to local selection.
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parasitism of the soybean aphid Aphis glycines by binodoxys communis the role of aphid defensive behaviour and parasitoid reproductive performance
Bulletin of Entomological Research, 2008Co-Authors: Kris A G Wyckhuys, Nicolas Desneux, Keith R Hopper, Laura Hocum L Stone, Kim A Hoelmer, George E HeimpelAbstract:The Asian parasitoid, Binodoxys communis (Gahan) (Hymenoptera: Braconidae), is a candidate for release against the exotic soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in North America. In this study, we examined preferences by B. communis for the different developmental stages of A. glycines and investigated consequences of these preferences for parasitoid fitness. We also determined to what extent aphid defensive behaviours mediate such preferences. We found that B. communis readily attacks and successfully develops in the different A. glycines developmental stages. Binodoxys communis development time gradually increased with aphid developmental stage, and wasps took longest to develop in alates. An average (±SE) of 54.01±0.08% of parasitized A. glycines alatoid nymphs transformed into winged adult aphids prior to mummification. No-choice assays showed a higher proportion of successful attacks for immature apterous A. glycines nymphs compared to adults and alatoid nymphs. Also, choice trials indicated avoidance and lower attack and oviposition of adults and alatoid nymphs. The different aphid stages exhibited a range of defensive behaviours, including body raising, kicking and body rotation. These defenses were employed most effectively by larger aphids. We discuss implications for the potential establishment, spread and biological control efficacy of A. glycines by B. communis in the event that it is released in North America.
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suppression of population growth of the soybean aphid Aphis glycines matsumura by predators the identification of a key predator and the effects of prey dispersion predator abundance and temperature
Environmental Entomology, 2006Co-Authors: Nicolas Desneux, Robert J OneilAbstract:The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), has recently invaded North America from Asia and has become a major pest in soybean. Using field surveys and cage exclusion techniques, we identified the effect of natural enemies and abiotic factors on the growth of soybean aphid populations in 2004 and 2005. The soybean aphid population was significantly limited by natural enemies in the field. Generalist predators dominated the natural enemy community. One species, Orius insidiosus Say (Hemiptera: Anthocoridae) represented 85–90% of predators found. There was a significant negative relationship between aphid population growth and O. insidiosus abundance. For other predators, there were no relationships between abundance and aphid population growth. The spatial distribution of aphids among plants affected the impact of O. insidiosus on aphid population growth. When aphids were distributed in a clumped manner, increases in O. insidiosus numbers resulted in lower aphid growth rates. For randomly distributed aphids, there was no effect of O. insidiosus abundance on aphid population growth. Finally, we found no relationship between aphid population growth and degree-day accumulations. The potential of O. insidiosus to suppress soybean aphid population growth at low aphid numbers and the importance of the predator to soybean aphid integrated pest management are discussed.
Kongming Wu - One of the best experts on this subject based on the ideXlab platform.
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identification and expression profiling of odorant binding proteins and chemosensory proteins between two wingless morphs and a winged morph of the cotton aphid Aphis gossypii glover
PLOS ONE, 2013Co-Authors: Shaohua Gu, Kongming Wu, L M Field, J A Pickett, Yongjun Zhang, Jingjiang ZhouAbstract:Insects interact with their environment and respond to the changes in host plant conditions using semiochemicals. Such ecological interactions are facilitated by the olfactory sensilla and the use of olfactory recognition proteins. The cotton aphid Aphis gossypii can change its phenotype in response to ecological conditions. They reproduce mainly as wingless asexual morphs but develop wings to find mates or new plant hosts under the influence of environmental factors such as temperature, plant nutrition and population density. Two groups of small soluble proteins, odorant binding proteins (OBPs) and chemosensory proteins (CSPs) are believed to be involved in the initial biochemical recognition steps in semiochemical perception. However, the exact molecular roles that these proteins play in insect olfaction remain to be discovered. In this study, we compared the transcriptomes of three asexual developmental stages (wingless spring and summer morphs and winged adults) and characterised 9 OBP and 9 CSP genes. The gene structure analysis showed that the number and length of introns in these genes are much higher and this appears to be unique feature of aphid OBP and CSP genes in general. Another unique feature in aphids is a higher abundance of CSP transcripts than OBP transcripts, suggesting an important role of CSPs in aphid physiology and ecology. We showed that some of the transcripts are overexpressed in the antennae in comparison to the bodies and highly expressed in the winged aphids compared to wingless morphs, suggesting a role in host location. We examined the differential expression of these olfactory genes in ten aphid species and compared the expression profile with the RNA-seq analyses of 25 pea aphid transcriptome libraries hosted on AphidBase.
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the endosymbiont arsenophonus is widespread in soybean aphid Aphis glycines but does not provide protection from parasitoids or a fungal pathogen
PLOS ONE, 2013Co-Authors: Jason A Wulff, George E Heimpel, Kongming Wu, Karrie A Buckman, Jennifer A WhiteAbstract:Aphids commonly harbor bacterial facultative symbionts that have a variety of effects upon their aphid hosts, including defense against hymenopteran parasitoids and fungal pathogens. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is infected with the symbiont Arsenophonus sp., which has an unknown role in its aphid host. Our research goals were to document the infection frequency and diversity of the symbiont in field-collected soybean aphids, and to determine whether Arsenophonus is defending soybean aphid against natural enemies. We performed diagnostic PCR and sequenced four Arsenophonus genes in soybean aphids from their native and introduced range to estimate infection frequency and genetic diversity, and found that Arsenophonus infection is highly prevalent and genetically uniform. To evaluate the defensive role of Arsenophonus, we cured two aphid genotypes of their natural Arsenophonus infection through ampicillin microinjection, resulting in infected and uninfected isolines within the same genetic background. These isolines were subjected to parasitoid assays using a recently introduced biological control agent, Binodoxys communis [Braconidae], a naturally recruited parasitoid, Aphelinus certus [Aphelinidae], and a commercially available biological control agent, Aphidius colemani [Braconidae]. We also assayed the effect of the common aphid fungal pathogen, Pandora neoaphidis (Remaudiere & Hennebert) Humber (Entomophthorales: Entomophthoraceae), on the same aphid isolines. We did not find differences in successful parasitism for any of the parasitoid species, nor did we find differences in P. neoaphidis infection between our treatments. Our conclusion is that Arsenophonus does not defend its soybean aphid host against these major parasitoid and fungal natural enemies.
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flight performance of the soybean aphid Aphis glycines hemiptera aphididae under different temperature and humidity regimens
Environmental Entomology, 2008Co-Authors: Ying Zhang, Kris A G Wyckhuys, Kongming Wu, Limin Wang, George E HeimpelAbstract:The soybean aphid, Aphis glycines (Matsumura), is native to eastern Asia and has recently invaded North America, where it is currently the most important insect pest of soybeans. The soybean aphid has spread rapidly within North America, presumably through a combination of active and passive (wind-aided) flight. Here, we studied the active flight potential of A. glycines under a range of environmental conditions using an aphid flight mill. Winged (alate) A. glycines were tested on a specially designed 32-channel, computer-monitored flight mill system. Aphids that were 12–24 h old exhibited the strongest flight behavior, with average flight durations of 3.3–4.1 h, which represented flight distances of 4.6–5.1 km. After the age of 72 h, A. glycines flight performance rapidly declined. The optimum temperature range for flight was 16–28°C, whereas optimum relative humidity was 75%. Our findings show that A. glycines posseses a fairly strong active flight aptitude (ability and inclination) and point to the possibility of flight initiation under a broad range of environmental conditions. These results have the potential to aid forecasting and management protocols for A. glycines at the landscape level.
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population dynamics of Aphis glycines homoptera aphididae and its natural enemies in soybean in northern china
Annals of The Entomological Society of America, 2004Co-Authors: Kongming Wu, Keith R Hopper, Kuijun ZhaoAbstract:Abstract A field survey of soybean aphid, Aphis glycines Matsumura, and its natural enemies was conducted during summer 2002 in Langfang, northern China (116.4° E, 39.3° N). Aphids colonized soybean when plants were still small in early July. After a lag of 2 wk, aphid density increased rapidly in late July, reaching a peak of 114 ± 46 aphids per five soybean plants on 1 August. The population declined to a plateau immediately after this peak and then declined again starting in mid-August, although a second small peak occurred in late August. The finite rate of increase varied from zero- to five-fold, and the aphid seemed to be limited by natural enemies. The main species of natural enemy were the aphid parasitoid Lysiphlebus sp., the aphid predators Propylaea japonica (Thunberg), Scymnus (Neopullus) babai Sasaji, and Paragus tibialis (Fallen). In a field exclosure experiment, A. glycines density in small-mesh cages peaked three-fold higher than in large-mesh cages and 12-fold higher than on uncaged plant...
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influences of bacillus thuringiensis berliner cotton planting on population dynamics of the cotton aphid Aphis gossypii glover in northern china
Environmental Entomology, 2003Co-Authors: Kongming WuAbstract:Abstract The influence of Bacillus thuringiensis Berliner (Bt) cotton on population dynamics of cotton aphid, Aphis gossypii Glover, was investigated during 1999–2000 in northern China. The field experiments were conducted in plots of Bt cotton and conventional cotton that received no insecticide applications, and in plots of conventional cotton in which pyrethroid and organophosphate insecticides were used regularly for control of Helicoverpa armigera. The results indicate that resistance of cotton aphids to majority of insecticides used for control of H. armigera, and lower densities of predators in late June and early July caused by insecticide use, causes population densities of cotton aphids to become significantly higher in plots of insecticide-treated conventional cotton than in Bt cotton plots. These results suggest that Bt cotton planting not only played an important role in the control of H. armigera, but also efficiently prevented cotton aphid resurgence in response to insecticide use.
Jerome Carletto - One of the best experts on this subject based on the ideXlab platform.
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dna based discrimination between the sibling species Aphis gossypii glover and Aphis frangulae kaltenbach
Systematic Entomology, 2009Co-Authors: Jerome Carletto, Aurelie Blin, Flavie VanlerberghemasuttiAbstract:Morphologically similar species occur in various groups of insects, including aphid pests. In Europe, Aphis frangulae Kaltenbach and Aphis gossypii Glover (sometimes considered as subspecies) are differentiated usually on the basis of life cycle and host plant. We used a sexual population of A. frangulae collected on the primary host and samples of A. gossypii collected on cucurbits or cotton for the development of molecular markers. DNA sequence data for the gene encoding cytochrome b and for the barcode region of cytochrome oxidase I, as well as a length polymorphism for an intron in the sodium channel para-type gene discriminated unambiguously between the two taxa. These markers were also used as identification keys for aphids collected on crops belonging to the Solanaceae. The cytochrome b marker differentiates host-related Aphis gossypii haplotypes, and the para-type gene intron might be suitable for the resolution of taxonomic problems in other aphid species complexes.
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DNA‐based discrimination between the sibling species Aphis gossypii Glover and Aphis frangulae Kaltenbach
Systematic Entomology, 2009Co-Authors: Jerome Carletto, Aurelie Blin, Flavie Vanlerberghe‐masuttiAbstract:Morphologically similar species occur in various groups of insects, including aphid pests. In Europe, Aphis frangulae Kaltenbach and Aphis gossypii Glover (sometimes considered as subspecies) are differentiated usually on the basis of life cycle and host plant. We used a sexual population of A. frangulae collected on the primary host and samples of A. gossypii collected on cucurbits or cotton for the development of molecular markers. DNA sequence data for the gene encoding cytochrome b and for the barcode region of cytochrome oxidase I, as well as a length polymorphism for an intron in the sodium channel para-type gene discriminated unambiguously between the two taxa. These markers were also used as identification keys for aphids collected on crops belonging to the Solanaceae. The cytochrome b marker differentiates host-related Aphis gossypii haplotypes, and the para-type gene intron might be suitable for the resolution of taxonomic problems in other aphid species complexes.
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genetic diversity of the cotton aphid Aphis gossypii in the unstable environment of a cotton growing area
Agricultural and Forest Entomology, 2008Co-Authors: Thierry Brevault, Jerome Carletto, Daphne Linderme, Flavie VanlerberghemasuttiAbstract:1 Spatial and temporal habitat heterogeneity represented by annual crops is a major factor influencing population dynamics of phytophagous insect pests such as the cotton aphid Aphis gossypii Glover. We studied the effects of instability of the cotton agroecosystem resulting from the temporary availability of the plant resource and the repeated use of insecticides on the genetic variability of the cotton aphids. 2 Samples of A. gossypii were collected in cotton plots, treated or not with insecticides and from vegetable crops (Malvaceae, Cucurbitaceae and Solanaceae) within the cotton growing area of northern Cameroon. The genetic structure of the samples was assessed using eight microsatellite markers. Insecticide resistance was estimated through the detection of two mutations in the ace-1 gene that are associated with insensitivity of acetylcholinesterase to carbamate and organophosphate insecticides. 3 The results obtained show that both host plants and insecticides act in genetic structuring of A. gossypii. Ninety-three percent of aphids collected on cotton were characterized by the same microsatellite multilocus genotype, Burk1, which also displays the insecticide resistant alleles. 4 During the dry season, the cotton crop season after, the genotype Burk1 was principally found on two other malvaceous cultivated plants, rosella and okra, acting as suitable reservoir plants. The ability of the cotton aphid to move among asynchronous suitable habitats in response to changes in resource availability enables the pest to exploit unstable cropping systems. An understanding of the cotton aphid life system may aid to improve strategies for integrated resistance management.
