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The sugarcane aphid [SCA, Melanaphis sacchari (Zehntner), Hemiptera: Aphididae], is the predominant pest of US-grown sorghum [Sorghum bicolor (L.) Moench]. A previous study found that a single clone was prevalent on samples collected from sorghum in seven states and one territory of the United States in 2015. We sought to determine if this clone was still prevalent on sorghum grown in 2016 and if this clone is also found on Johnsongrass [S. halepense (L.) Pers.]. Forty-six SCA samples were collected from primarily sorghum and Johnsongrass from 10 cities in four states, and three aphid samples from different genera (Sipha, Rhopalosiphum, and Acyrthosiphon) were obtained. These aphid samples were genotyped with 43 SCA simple sequence repeat (SSR) markers. The predominant aphid clone found on sorghum in 2015 was again the predominant genotype in the 2016 SCA samples collected from sorghum. This same genotype was also found for the SCA samples collected from Johnsongrass in 2015 and 2016, although two samples differed at a single locus. Mixtures of this predominant genotype with three additional genotypes of SCAs were detected for three samples (excluding the control), indicating that multiple genotypes do exist in the United States but at low levels. This study provides evidence that a SCA “super-clone” has maintained its dominance on sorghum, and it is using the perennial Johnsongrass as an alternative host.

We review yield effects caused by aphid feeding and associated virus injury to cereal, oilseed and pulse crops, and estimate the potential economic loss caused by aphids in Australia. Potential yield reduction due to aphids was determined through a survey of quantitative data from experiments that assessed aphids' effect on grain yield. In cereals, four aphids caused damage; on barley, feeding injury caused by Rhopalosiphum padi + Rhopalosiphum maidis was most damaging in terms of yield reduction (25.5%) with an economic loss of $19/ha. Barley yellow dwarf virus transmitted by R. padi + Sitobion miscanthi was more damaging than direct feeding, causing a yield reduction of 39% and economic loss of $21/ha for wheat. On canola, beet western yellow virus transmitted by Myzus persicae caused the highest yield reduction of 34% and economic loss of $115/ha, although this was measured through artificial inoculations. Feeding injury was high in Brevicoryne brassicae which caused an average yield reduction of 34% and associated economic loss of $88.5/ha, while Lipaphis erysimi and M. persicae had negligible economic effects but more data are needed. On pulses, the most economically damaging (unidentified) aphids feeding on lupins caused a yield reduction of 43% and economic loss of $24/ha. The aphids M. persicae + Aphis craccivora + Acyrthosiphon kondoi reduced lupin yields by 13% and economic returns by $7.40/ha. On field peas, a 14% reduction in yield was caused by transmitted viruses such as pea seed-borne mosaic virus which caused economic losses of $20.50/ha. In total, feeding and virus injuries resulted in potential economic costs of $241 and $482 million/year, respectively. Although this review provides estimates of potential yield and economic losses due to aphids, few data were available for some crops, aphid species or regions (e.g. oats). Nevertheless, economic costs associated with aphids appear substantial.

The population dynamics of three apple aphids (Dysaphis plantaginea Pass., Rhopalosiphum insertum Walk., and Aphis pomi De Geer) in a representative orchard of Eastern Switzerland was simulated with a system of differential equations incorporating time-varying and age-specific life table parameters. Visual comparisons of simulated with observed population trends were quite satisfactory. The models were used to gain better insights into the aphid life systems for future use in integrated pest management (IPM) programs. Zusammenfassung Simulationsmodelle der Dynamik der drei Apfelblattlause Dysaphis plantaginea, Rhopalosiphum insertum und Aphis pomi (Homoptera, Aphididae) in einer Schweizer Obstanlage Die Populationsdynamik von drei Apfelblattlausen (Dysaphis plantaginea Pass., Rhopalosiphum insertum Walk. und Aphis pomi De Geer) in einer reprasentativen Obstanlage der Ostschweiz wurde mit einem System von Differentialgleichungen simuliert. Die Modelle wurden auf altersspezifischen, zeitvariablen Lebenstafelparametern aufgebaut. Der visuelle Vergleich der simulierten mit den im Freiland beobachteten Populationsentwicklungen zeigte eine gute Uberein-stimmung. Die Modelle ermoglichen einen tieferen Einblick in die Lebenssysteme der Blattlause und liefern damit eine verbesserte Grundlage fur integrierte Pflanzenschutzprogramme.

A phylogeny of the tribe Aphidini (Hemiptera: Aphididae) was reconstructed from three gene fragments: two mitochondrial regions, partial tRNA-leucine + cytochrome oxidase II (tRNA/COII), partial 12S rRNA + tRNA-valine + 16S rRNA (12S/16S) and one nuclear gene, the elongation factor-1 alpha (EF1α). Bayesian phylogenetic (BP) analyses were performed on each individual dataset of tRNA/COII, 12S/16S and EF1α, and maximum parsimony (MP), Bremer support test, maximum likelihood (ML) and BP analysis were performed on the combined dataset. After comparing our molecular phylogenetic results with the classic classification based on morphological and ecological data, we analysed three main issues: the monophyletic relationships among tribes and subtribes, the validities of the latest taxonomic positions of genera and species and the status of certain Aphis species groups. Our results indicate that 36 of the species analysed, with the exception of Cryptosiphum artemisiae, are clustered within the clade of Aphidini. Also, the 28 species representative of the subtribe Aphidina were separated from the eight species representative of Rhopalosiphina; each monophyletic subtribe was supported by significant P-values in the combined analysis. According to our results, Cryptosiphum should be moved to Macrosiphini because it is more closely related to the genera Lipaphis and Brevicoryne. The genus Toxoptera was recovered as non-monophyletic. In Rhopalosiphina, three genera, Hyalopterus, Rhopalosiphum and Schizaphis, were relatively closer to each other than to the genus Melanaphis. In the relationships between species-groups among Aphis, most species were separated into two main lineages; the fabae group seemed to be more closely related to the spiraecola and craccivora group rather than to the gossypii group.

Despite the relative ease of isolating microsatellites, their development still requires substantial inputs of time, money and expertise. For this reason there is considerable interest in using existing microsatellites on species from which markers were not cloned. We tested cross-species amplification of 48 existing aphid loci in species of the following genera: Aphidinae: Aphidini: Aphis and Rhopalosiphum ; Aphidinae: Macrosiphini: Acyrthosiphum , Brevicoryne , Diuraphis , Illinoia , Macrosiphoniella , Macrosiphum , Metopeurum , Metapolophium , Myzus , Phorodon , Sitobion and Uroleucon and Neuquenaphidinae: Neuquenaphis . Our results show cross-species application of known microsatellite loci is a highly promising source of codominant markers for population genetic and evolutionary studies in aphids.

Records are provided of the aphidiine parasites of aphids, Lysiphlebus fabarum (Marshall) and L. testaceipes (Cresson), parasitizing species of Aphis Linnaeus, Rhopalosiphum Koch and Toxoptera Koch in eastern Australia. Both species of Lysiphlebus were imported into Australia in 1982 for purposes of biological control, evidently with little or no initial success. Lysiphlebus testaceipes, however, has been reared in abundance in eastern Australia since 1997. A brief account is given of the history of the parasites in Australia and the possible provenance of recently collected material is discussed. Characters to distinguish between the two species are provided.

An unusual observation of Rhopalosiphum rufiabdominalis (Sasaki) causing damage to a banana plant in a glasshouse is reported. The association of 3 other Rhopalosiphum spp. with damage to bananas is noted, including a name correction for an aphid reported by Magee (1940) as a vector of banana mosaic virus.

The distinct morphs of Rhopalosiphum maidis (Fitch) and R. padi (L.) were morphologically and taxonomically studied. Keys are given to the apterous and alate viviparous adult females as well as to larvae of all instars of the two species of genus Rhopalosiphum, on maize plants in Egypt. The population dynamics of Rhopalosiphum maidis (Fitch) and R. padi (L.) were studied in untreated maize field in Shebin El-Kom, under natural field conditions. Corn leaf aphid [Rhopalosiphum maidis (Fitch)] density was most frequently found in contrary than oat cherry bird aphid [Rhopalosiphum padi (L.)] density from July to October. Zusammenfassung Untersuchungen zur Okologie und Taxonomie von Mais-Aphiden in Agypten Es wurden die verschiedenen Morphen von Rhopalosiphum maidis (Fitch) und R. padi (L.) morphologisch und taxonomisch untersucht. Bestimmungsschlussel zu den ungeflugelten und geflugelten viviparen adulten Weibchen sowie uber alle Larvenformen der zwei an Mais in Agypten auftretenden Arten werden aufgestellt. Im Freiland, auf unbehandelten Maisfeldern in Shebin El-Kom, wurde die Populationsdynamik von R. maidis und R. padi untersucht. Im Gegensatz zu R. padi wurde die groste Dichte von R. maidis zwischen Juli und Oktober festgestellt.

The effects of the indole alkaloid gramine on the behavior of the aphids Schizaphis graminum and Rhopalosiphum padi feeding on barley seedlings and on artificial diets were studied. On barley cv. F. Union, which lacks gramine, S. graminum ingested from phloem tissue for 30–80 min and non-phloem for 20–40 min, over a period of 3 h. In cultivar Datil ‘S’, gramine was found only in the epidermis and parenchyma mesophyll cells. On this cultivar, the non-phloem wave form of S. graminum was not observed. On F. Union, R. padi ingested non-phloem with short periods of ingestion from phloem. On cv. Datil ‘S’, this aphid did not show the non-phloem wave form. In experiments performed with cv. F. Union seedlings that contained exogenous gramine S. graminum did not ingest from phloem. Exogenous gramine was found only in the vascular bundles. It is suggested that gramine content and location may affect the feeding behavior of aphids in barley. Resume Effects de la gramine sur le comportement alimentaire de Schizaphis graminum et Rhopalosiphum padi Les effets de la gramine sur le comportement alimentaire des pucerons Schizaphis graminum et Rhopalosiphum padi on ete etudies en plantules d'orge (Hordeum distichum) et aussi avec des dietes artificielles a l'aide d'un moniteur electronique. S. graminum se nourri pendant 30–80 minutes a partir du phloeme et il a pris 20–40 minutes en se nourrisant d'autres tissues divers, d'un total de 3 heures d'exposition a la plante. Dans la culture Datil ‘S’ la gramine a ete trouvee seulement dans les cellules de l'epidermis et du parenchyme du mesophyle. Dans ce cas, l'onde non-phloematique de S. graminum, n'a ete pas observe; le temps pour le premiere onde X a ete plus prolonge par rapport a la culture F. Union. Dans la culture F. Union, R. padi se nourri principalement de tissue non-phloematique (35–100 minutes) et du phloeme par des breves periodes (15–25 minutes). Dans le cas de la culture Datil ‘S’ ce puceron n'a pas montre l'onde X. D'autre part, quand les plantules de F. Union ont ete poussees dans des solution avec gramine, S. graminum ne se nourri pas du phloeme, tandis que R. padi montre un comportement similaire a celui-ce observe avec plantules sans gramine. La gramine absorbe par les plantules a ete retrouvee seulement dans les faisceaux vasculaires. D'autre part, la gramine dans des dietes artificielles agit comme repulsif alimentaire a partir de concentrations de 0,5 mM. Avec des dietes contenant 3 mM de gramine l'alimentation des pucerons a ete inhibee. Pourtant, ces resultats sugerent que le contenu et la localisation de la gramine peuvent modifier le comportement alimentaire des pucerons en plantules d'orge.

1. The eggs of Rhopalosiphum insertum (Walker) showed a seasonal increase in cold-hardiness under field conditions. Their supercooling point fell from -35°C in November to below -40°C in January, then rose to-35°C or above by March. 2. Laboratory experiments demonstrated that both temperature and date affected cold-hardiness of the eggs. The supercooling points of eggs kept at 16 h photoperiod or in darkness did not, however, differ significantly. 3. Eggs brought from the field into warm, long-day conditions would not hatch until after mid-January. After this date, per cent hatch was significantly greater in 16 h photoperiod than in darkness; it did not differ between eggs kept at 5 or 0°C, but was reduced at -5°C. 4. It is concluded that eggs of Rinserturn are in diapause until mid-January, and that hatching rate and cold-hardiness are determined by separate environmental factors.

A virus disease ofBrassica juncea Coss., B. Mnensis L. and Raphanus sativus L. var.hortensis Backer occurs in Trinidad, but is not serious. Rape (Brassica napus L.), turnip(B. rapa L.) and Lepidium virginicum L. are susceptible, but cabbage, cauliflower, kohlrabi and the European radish seem to be immune. Zinnia elegans Jacq. and tobacco (Nicotiana tabacum L.) are also susceptible, but no infections were obtained on six other Nicotiana species, beetroot, Swiss chard and cowpea. Tobacco gives only necrotic local lesions, whereas the other hosts give no local lesions, but a systemic mottling, usually accompanied in crucifers by leaf deformation and stunting of the plant. The virus is transmitted by Rhopalosiphum pseudobrassicae (Davis), which is probably responsible for spread in the field. Its thermal inactivaticm-point is 58d C, dilution end-point 1:1000, and longevity in vitro 4 days at 16–18d C. and 3 days at 24–30d C. The properties and host range of this virus are compared with those of others affecting the Cruciferae. It has affinities with some of them, but is considered to be distinct.

SUMMARY The numbers of several species of grass aphids caught on cylindrical sticky traps at Rothamsted Experimental Station from 1942–46 and from 1951–69, and at Broom's Barn Experimental Station from 1960–69, are given. Metopolophium dirhodum was the commonest grass-feeding aphid caught. M. dirhodum and Metopolophium festucae are attracted to yellow traps, which were used from 1946 onwards, but relatively few M. festucae were caught compared with M. dirhodum. Macrosiphum avenae, Macrosiphum fragariae and Rhopalosiphum spp. are not strongly attracted to yellow but are impacted by the wind on sticky traps. M. avenae 2ind Metopolophium dirhodum were exceptionally abundant at Rothamsted in 1968. Macrosiphum avenae was also exceptionally abundant at Broom's Barn in 1968, but the largest catch there of Metopolophium dirhodum was in 1961.

SUMMARY The response to plant spacing by flying and landing aphids has been studied using cylindrical and horizontal sticky traps over cocksfoot and kale crops. Some aphid species showed a significant response to spacing, being caught more frequently over wide-than close-spaced crops; the regressions of catches over widely-spaced on those over close-spaced plants suggested that most of the species caught followed this trend irrespective of the host plant. The landing response to spacing on horizontal traps at 0.3 m was normally greater than that on cylindrical traps at 1 m. At 1 m, some species (e.g. Aphis fabae gp.) gave a different response to spacing in the two crops, whilst others (e.g. Rhopalosiphum oxyacanthae) responded similarly to both crop spacings. In contrast to previous results with other aphid species and spaced groundnuts, the landing response of Rhopalosiphum spp. was elicited both when there was a cover crop (clover) between widely-spaced drills of cocksfoot and by widely-spaced cocksfoot alone. It is suggested that one stimulus eliciting the landing response with widely-spaced plants is the electromagnetic emission from bare earth between the plants. Aphid landing behaviour was influenced by the spacing of both cocksfoot and kale plants.

Some barley yellow-dwarf (BYD) viruses isolated from cereal crops in Great Britain were transmitted by Rhopalosiphum padi, L. and others were not. Sitobion fragariae (Walker), S. avenae (Fabricius), and Metopolophium dirhodum (Walker) all transmitted viruses of both types, but they usually transmitted those of which Rhopalosiphum was a vector less readily than did R. padi. The transmissibility of a virus by a given aphid species was not affected by transmission with another, less efficient, vector species. Neomyzus circumflexus (Buckt.) and Rhopalosiphum maidis (Fitch) transmitted the few viruses with which they were tested. A few R. padi acquired virus from infected leaves during 30 min. feeding and inoculated healthy seedlings during 15 min. feeding, but the minimum total time taken to acquire and transmit was 10 hr. and 32 hr. were needed for about half the aphids that were able to acquire and transmit virus to do so. This may indicate the existence of a short latent period of the virus in the vector, although the evidence is not conclusive. The times spent on infected plants influenced the results more than those spent on healthy ones; many transmissions occurred with short feeding times on healthy plants so long as the time spent on infected leaves was long, but the reverse was not true. Nymphs of R. padi that moulted after they left infected plants on which they fed long enough to become infective, infected slightly fewer plants than adults fed for the same times.

SUMMARY The longevity of Sitobion avenae varied inversely with temperature from 25 to over 100 days when reared outdoors on barley under lantern jars, being longest between December and April–May. This was due mainly to changes in the length of the pre- and post-reproductive periods rather than the length of the period of reproduction. Fecundity varied directly with temperature, from eight to sixty-seven nymphs per female. When reared on winter wheat and sheltered from wind, rain and snow, S. avenae survived best, Metopolophium dirhodum survived less well and Rhopalosiphum padi worst; when exposed in the open none of the three species survived. Close relationships were not demonstrable between the numbers of alate M. dirhodum, S. avenae and Rhopalosiphum spp. trapped in any year, between the abundance of these aphids and weather conditions between January and April, or between the numbers of these alatae and the size of crop infestations. This was probably because insufficient information was available about their biology, both inside and outside the crop.