Aphid

About: Aphid is a research topic. Over the lifetime, 11380 publications have been published within this topic receiving 229721 citations. The topic is also known as: Aphidoidea & plant lice.

Sugarcane Aphid (Hemiptera: Aphididae): Host Range and Sorghum Resistance Including Cross-Resistance from Greenbug Sources

Abstract: The graminous host range and sources of sorghum [Sorghum bicolor (L.) Moench.] plant resistance, including cross-resistance from greenbug, Schizaphis graminum (Rondani), were studied for the newly emerging sugarcane aphid, Melanaphis sacchari (Zehntner), in greenhouse no-choice experiments and field evaluations. The sugarcane aphid could not survive on field corn, Zea mays (L.), Teff grass, Eragrostis tef (Zucc.), proso millet, Panicum miliaceum L., barley, Hordeum vulgare L., and rye, Secale cereale L. Only sorghum genotypes served as hosts including Johnsongrass, Sorghum halepense (L.), a highly suitable noncrop host that generates high numbers of sugarcane aphid and maintains moderate phenotypic injury. The greenbug-resistant parental line RTx2783 that is resistant to greenbug biotypes C and E was resistant to sugarcane aphid in both greenhouse and field tests, while PI 55607 greenbug resistant to biotypes B, C, and E was highly susceptible. PI 55610 that is greenbug resistant to biotypes B, C, and E maintained moderate resistance to the sugarcane aphid, while greenbug-resistant PI 264453 was highly susceptible to sugarcane aphid. Two lines and two hybrids from the Texas A&M breeding program B11070, B11070, AB11055-WF1-CS1/RTx436, and AB11055-WF1-CS1/RTx437 were highly resistant to sugarcane aphid, as were parental types SC110, SC170, and South African lines Ent62/SADC, (Macia/TAM428)-LL9, (SV1*Sima/IS23250)-LG15. Tam428, a parental line that previously showed moderate resistance in South Africa and India, also showed moderate resistance in these evaluations. Overall, 9 of 20 parental sorghum entries tested for phenotypic damage in the field resulted in good resistance to the sugarcane aphid and should be utilized in breeding programs that develop agronomically acceptable sorghums for the southern regions of the United States.

Climate change and cereal aphids: the relative effects of increasing CO2 and temperature on aphid population dynamics

Abstract: Experimental evidence regarding the responses of cereal aphids to rising atmospheric CO2 has been ambiguous. Some studies suggest increased population sizes under future CO2 levels, others suggest decreased population sizes, and still others suggest little or no difference. Recently, Newman et al. (2003) constructed a general mathematical model of the aphid–grass interaction to investigate whether or not we should, in fact, expect a general aphid response to rising CO2. They concluded that aphid populations are likely to be larger under future CO2 concentrations if soil N levels are high, the aphid species' nitrogen requirement is low and the aphid species' density-dependent response in winged morph production is weak. In that model, and in field experiments, CO2 concentration influences aphid population dynamics through the effect it has on plant quality. However, future CO2 concentrations are also likely to be accompanied by higher ambient temperatures, a combination that has received little focus to date. In the present paper, the Newman et al. model is used to consider the combined effects of increased CO2 concentrations and temperature on aphid population sizes. It is concluded that, when both factors are elevated, aphid population dynamics will be more similar to current ambient conditions than expected from the results of experiments studying either factor alone. This result has important implications for future experimentation.

Attraction of two lacewing species to volatiles produced by host plants and aphid prey.

Abstract: It is well documented that host-related odors enable many species of parasitoids and predatory insects to locate their prey and prey habitats. This study reports the first characterization of prey and prey host odor reception in two species of lacewings, Chrysoperla carnea (Say) and Chrysopa oculata L. 2-Phenylethanol, one of the volatiles emitted from their prey's host plants (alfalfa and corn) evoked a significant EAG response from antennae of C. carnea. Traps baited with this compound attracted high numbers of adult C. carnea, which were predominantly females. One of the sex pheromone components (1R,4aS,7S,7aR)-nepetalactol of an aphid species, Acyrthosiphon pisum (Harris) attracted only C. oculata adults. Single sensillum recordings showed that the olfactory neurons of C. carnea responded to both 2-phenylethanol and aphid sex pheromone components, but those of C. oculata only responded to the latter.

An aphid-resistance locus is tightly linked to the nematode-resistance gene, Mi, in tomato.

Abstract: Tomato lines from diverse breeding programs were evaluated in the field for resistance to a natural infestation of the potato aphid, Macrosiphum euphorbiae, in Davis, CA. It was noted that all lines that carried the nematode-resistance gene, Mi, displayed aphid resistance. A greenhouse assay for aphid resistance was developed to investigate this relationship. Association of nematode and aphid resistances in near-isogenic lines suggested that these traits are tightly linked. Analysis of an F2 population segregating for nematode resistance indicated that aphid resistance segregated as a single major locus genetically linked to Mi. The name Meu1 is proposed for this locus. It is likely that Meu1 was introduced into tomato along with Mi from the wild species Lycopersicon peruvianum. The presence of aphid resistance in the line Motelle, which contains a very small region of introgressed DNA, and the lack of recombinants suggest that Meu1 is tightly linked to Mi or possibly is the same gene. The map-based strategy currently being used to clone Mi should be applicable to cloning Meu1.

Bacterial Communities Associated with Host-Adapted Populations of Pea Aphids Revealed by Deep Sequencing of 16S Ribosomal DNA

Abstract: Associations between microbes and animals are ubiquitous and hosts may benefit from harbouring microbial communities through improved resource exploitation or resistance to environmental stress The pea aphid, Acyrthosiphon pisum, is the host of heritable bacterial symbionts, including the obligate endosymbiont Buchnera aphidicola and several facultative symbionts While obligate symbionts supply aphids with key nutrients, facultative symbionts influence their hosts in many ways such as protection against natural enemies, heat tolerance, color change and reproduction alteration The pea aphid also encompasses multiple plant-specialized biotypes, each adapted to one or a few legume species Facultative symbiont communities differ strongly between biotypes, although bacterial involvement in plant specialization is uncertain Here, we analyse the diversity of bacterial communities associated with nine biotypes of the pea aphid complex using amplicon pyrosequencing of 16S rRNA genes Combined clustering and phylogenetic analyses of 16S sequences allowed identifying 21 bacterial OTUs (Operational Taxonomic Unit) More than 98% of the sequencing reads were assigned to known pea aphid symbionts The presence of Wolbachia was confirmed in A pisum while Erwinia and Pantoea, two gut associates, were detected in multiple samples The diversity of bacterial communities harboured by pea aphid biotypes was very low, ranging from 3 to 11 OTUs across samples Bacterial communities differed more between than within biotypes but this difference did not correlate with the genetic divergence between biotypes Altogether, these results confirm that the aphid microbiota is dominated by a few heritable symbionts and that plant specialization is an important structuring factor of bacterial communities associated with the pea aphid complex However, since we examined the microbiota of aphid samples kept a few generations in controlled conditions, it may be that bacterial diversity was underestimated due to the possible loss of environmental or transient taxa