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Aphids are important sucking insects that attack many crops and cause huge economic loss. Essential oils have been proposed to be appropriate alternative to synthetic insecticides due to their low impact on environment and human health. In this work, the chemical compositions of eight essential oils extracted from plants growing in Egypt were determined by gas chromatography/mass spectrometry (GC–MS). The aphicidal activities of the isolated oils were examined against the adults of oleander aphid, Aphis nerii by a leaf-dipping assay. The inhibitory effect of essential oils on acetylcholinesterase (AChE) activity was also tested in vitro. Chemical analyses showed the essential oils consisted mainly of monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons and oxygenated sesquiterpenes except the oil of Artemisia monosperma which contained high content of benzenes. The results of toxicity assay showed that the oils of A. monosperma and Citrus sinensis were the most potent toxicants displaying LC50 value of 0.06 mg/L. The oils of Callistemon viminals, Schinus terebinthifolius and Schinus molle were also highly effective against aphid as their LC50 values were lower than 1 mg/L. In addition, the highest inhibitory effect on AChE was recorded by 0.5 mg/L C. sinensis with inhibition of 49.33%, while 0.1 mg/L Citrus lemon oil recorded the lowest inhibitory effect with inhibition of 0.4%. In general, six of tested essential oils showed high toxicity against A. nerii and they might be applied in the IPM programs for this insect.

In this study the possibility of using liquidInula viscosa(Dittrichia viscosa L.) to improve the growth and quality ofOscularia deltoidesandCorpuscolaria lehmaniiplants and protection againstAphis neriiwas evaluated. The 3 experimental groups in cultivation were: i) group without the use ofInula viscosaliquid macerate (CTRL), irrigated with water and previously fertilised substrate; ii) group treated with 1% ofInula viscosaliquid obtained from flowers (leaf spraying and soil irrigation), previously fertilized substrate (INU1); iii) group treated with 1% ofInula viscosaliquid obtained from leaves and stems (leaf spraying and soil irrigation), previously fertilized substrate (INU2). The test showed a significant increase in the agronomic parameters analyzed in plants treated with liquidInula viscosa. In fact, all plants treated with Inula showed a significant increase in plant height, leaves number, vegetative and roots weight, branches and flowers number and flowering time in bothCorpuscolaria lehmaniiandOscularia deltoides. An evaluation was also made of the number of individuals ofAphis neriipresent on the plants ofCorpuscolaria lehmaniiandOscularia deltoidesto assess whether the macerate of Inula can be used for the control of these insects. The GC-MS analysis of active fractions strongly suggested costic acid as the compound responsible for contact toxicity againstAphis nerii. Probably in the plant treated withInula viscosathere is an induction of the defense mechanisms that lead to greater resistance to biotic and abiotic stresses. The application of Inula macerate also improves the plant's defences against attacks by fungal pathogens and insects. Very interesting aspects, especially in view of a possible reduction of fertilizers and synthetic plant protection products.

Gymnema sylvestre, a perennial woody climber popular for its antidiabetic property and its leaves are widely recommended to use in the traditional system of medicine. The oleander aphid, Aphis nerii is a major pest of G. sylvestre from October to March in central India. The present study was carried out to evaluate the efficacy of different biorational insecticides like Azadiractin 1% EC (10000ppm), aqueous leaf extract (5%) of Kalmegh or the Creat, King of Bitters (Andrographis paniculata) and Indian bael or Golden apple (Aegle marmelos), insect growth regulator (Buprofezin 25% SC), commercial entomopathogenic formulations like Beauveria bassiana (2×109 spores/ml), Metarhizium anisopliae (2×109 spores/ml), Lecanicillium muscarium (Verticillium lecanii; 2×109 spores/ml) on A. nerii under laboratory and field condition during 2019 and 2020. It was discovered that the leaf spray method was superior to the leaf dipping method. In the leaf spray method, hundred percent mortality of A. nerii was recorded with the application of azadirachtin post 72 HAT and efficacy of B. bassiana, M. anisopliae and L. muscarium were statistically in the same group during both year of study. However, in the leaf dip method, hundred percent mortality of A. nerii was recorded with the treatment of azadirachtin post 96 HAR. In both bioassay methods, the lowest population reduction and mortality were observed in bael followed by kalmegh plant extract under laboratory conditions. On the tenth days of treatment, azadirachtin showed hundred percent reduction in the aphid population with hundred percent efficacy. The entomopathogenic fungi like M. anisopliae (85.4%, 87.8%) and B. bassiana (78.3%, 83.8%) were equally effective in reducing A. nerii population with the efficacy of (87.4%, 90.4%) and (81.2%, 87.2%) under field condition during 2019 and 2020 respectively.

Aphids are excellent experimental models for a variety of biological questions ranging from the evolution of symbioses and the development of polyphenisms to questions surrounding insect's interactions with their host plants. Genomic resources are available for several aphid species, and with advances in the next-generation sequencing, transcriptomic studies are being extended to non-model organisms that lack genomes. Furthermore, aphid cultures can be collected from the field and reared in the laboratory for the use in organismal and molecular experiments to bridge the gap between ecological and genetic studies. Last, many aphids can be maintained in the laboratory on their preferred host plants in perpetual, parthenogenic life cycles allowing for comparisons of asexually reproducing genotypes. Aphis nerii, the milkweed-oleander aphid, provides one such model to study insect interactions with toxic plants using both organismal and molecular experiments. Methods for the generation and maintenance of the plant and aphid cultures in the greenhouse and laboratory, DNA and RNA extractions, microsatellite analysis, de novo transcriptome assembly and annotation, transcriptome differential expression analysis, and qPCR verification of differentially expressed genes are outlined and discussed here.

The insecticidal activity of four natural products based on soaps prepared from plant oils (sunflower and olive) against Aphis nerii Boyer de Fonscolombe and Macrosiphum rosae (L.) was evaluated in vitro. It was found that SLGEL1521OLT, SLUN and OLGEL manifested the strongest insecticidal activity against both aphids. A higher efficacy was observed towards M. rosae, as compared with A. nerii. The number of surviving individuals was recorded after 24h. The efficacy was estimated by means of the Henderson and Tilton formula (1955) and the results were statistically analyzed with the R language for statistical computing (R Development Core Team, 2011) and the drc R language package.

Aphids and thrips are very important pest species of many greenhouse and field plants in the world. In recent years, there have been attempts to identify plants for their insecticidal property with a view to find out suitable alternatives to the indiscriminate use of chemical pesticides, which are a risk for human health and the environment. The aim of this work was to evaluate the insecticidal effect of Eucalyptus globulus Labill essential oil (EO) against Aphis nerll Boyer de Fonscolombe (Hemiptera: Aphididae) and Gynaikothrips ficorum Marchal (Thysanoptera: Ploeothridae). The EO was extracted by hydrodistillation and the bioassay was evaluated by toxicity contact method, using solutions at different concentrations and for different time intervals. The EO was more toxic to G. ficorum (LC50 = 0.031pL cm-2) than A. nerll(LC50 = 0.099pL cm-2) on filter discs at 12 h of exposure. These results suggested that EO from E. globulus constitute a good alternative for the control of A. nerll and G. ficorum, considering their insecticidal effects at low applied concentrations and for short periods of time. Los áfidos y trips son dos de las más importantes especies de plagas que Invaden Invernaderos y cultivos en el mundo. En los últimos años se han realizado muchos esfuerzos con el propósito de identificar plantas por sus propiedades insecticidas, como una alternativa al uso indiscriminado de insecticidas químicos que constituyen un riesgo para la salud humana y el medioambiente. El objetivo de este trabajo fue evaluar el efecto insecticida del aceite esencial (AE) de Eucalyptus globulus Labill sobre Aphis nerii Boyer de Fonscolombe (Hemiptera: Aphididae) y Gynaikothrips ficorum Marchal (Thysanoptera: Ploeothridae). El AE se extrajo por hidrodestilación y los bioensayos se evaluaron usando el método de toxicidad por contacto a diferentes concentraciones e intervalos de tiempo. Estudios exploratorios se realizaron previamente para determinar las concentraciones apropiadas de testeo. El AE fue más tóxico sobre G. ficorum (LC50 = 0.031|uL cm-2) que sobre A. nerii(LC50 = 0.099|uL cm-2) en el ensayo realizado en discos de papel de filtro correspondiente a las 12 h de exposición. Estos resultados sugieren que el AE de E. globulus constituye una buena alternativa para el control de A. nerii y G. ficorum considerando el efecto insecticida a bajas concentraciones y cortos tiempos de exposición.

Laboratory and semi- field experiments were carried out during 2013 winter season at Sharkia region to evaluate the performance of the parasitoid species Diaeretiella rapae (M'Intosh)for controlling Brevicoryne brassicae L., Aphis craccivora (Koch) and Aphis nerii Boyer infesting cabbage, faba bean and oleander plants. With the increase of parasitoid density, the percentage of parasitism increased to reach a maximum of 35.7, 29.7 and 25.2% for D. rapae at 11 parasitoid/200 aphids per jar in laboratory and a minimum of 11.30, 7.30 and 5.90% at one parasitoid per jar. Meanwhile, the highest percentage of parasitism were 92.20, 83.20 and 79.30% for D. rapae at 20 parasitoids/200aphids per cage in semi-field test, a minimum of 61.80, 48.70 and 41.50% recorded at five parasitoids per cage on B. brassicae, A. craccivora and A. nerii, respectively. On the other hand, with the increase of parasitoid density the percentage of emerged adults decreased to reach a maximum of 80.93, 75.54 and 63.85% for D. rapae at one parasitoid per jar in laboratory and 77.80, 73.56 and 57.90% at five parasitoids per cage in the field on B. brassicae, A. craccivora and A. nerii, respectively. With the increase of parasitoid density the fecundity of the parasitoid D. rapae increased (as number of mummies and emerged adults increased). The maximum numbers of mummies in the field were 185.60, 166.4 and 158.6 for D. rapae at 20 parasitoids per cage and minimum of 124.60, 97.40 and 83.0 mummies at five adults per cage. It is concluded that the parasitoid D. rapae could have the potential to be suitable biological control agent against B. brassicae, A. craccivora and A. nerii. Key words: Diaeretiella rapae, Brevicoryne brassicae, Aphis craccivora, Aphis nerii, Release, Density.

The oleander aphid, Aphis nerii Boyer de Fonscolombe, feeds on members of the Apocynaceae family. In Kentucky, A. nerii colonizes several Asclepias species and Cynanchum laeve. The prevalence of milkweeds and A. nerii in Kentucky ecosystems allow natural enemies, including the primary parasitoid Lysiphlebus testaceipes, to utilize this aphid as a resource. The efficacy of L. testaceipes when utilizing A. nerii reared on different host plant species was studied in the field and in the laboratory. In the laboratory, the time until first host contact and the number of ovipositional attempts by L. testaceipes did not vary among aphids from different host plant species. However significantly more aphids were mummified and more parasitoids successfully emerged from aphids on C. laeve than from aphids on tested Asclepias species. The successful emergence rates of L. testaceipes from A. nerii colonizing four species of milkweed were also determined in a naturally infested field plot. While no significant...

In a survey that was conducted during the year 2011, a local strain of Aphid lethal paralysis virus (ALPV) was identified and isolated from a wild population of Aphis nerii aphids living on Nerium oleander plants located in northern Israel. The new strain was tentatively named (ALPV-An). RNA extracted from the viral particles allowed the amplification and determination of the complete genome sequence. The virus genome is comprised of 9835 nucleotides. In a BLAST search analysis, the ALPV-An sequence showed 89 % nucleotide sequence identity with the whole genome of a South African ALPV and 96 and 94 % amino acid sequence identity with the ORF1 and ORF2 of that strain, respectively. In preliminary experiments, spray-applied, purified ALPV virions were highly pathogenic to the green peach aphid Myzus persicae; 95 % mortality was recorded 4 days post-infection. These preliminary results demonstrate the potential of ALPV for use as a biologic agent for some aphid control. Surprisingly, no visible ALPV pathogenic effects, such as morphological changes or paralysis, were observed in the A. nerii aphids infected with ALPV-An. The absence of clear ALPV symptoms in A. nerii led to the formulation of two hypotheses, which were partially examined in this study. The first hypothesis suggest that A. nerii is resistant or tolerant of ALPV, while the second hypothesis propose that ALPV-An may be a mild strain of ALPV. Currently, our results is in favor with the first hypothesis since ALPV-An is cryptic in A. nerii aphids and can be lethal for M. persicae aphids.

The study was performed to declare the effects of temperature and relative humidity on the population density of Aphis nerii, and the parasitoids, Diaeretiella rapae and Aphidius sp. at two districts, Zagazig and Mansoura (Sharkia and Dakahlia Governorates, respectively) throughout two seasons, 2005-2006 and 2006-2007 on Difla plants. The results indicated a highly significant positive correlation between temperature and population density of A. nerii in the second seasons at the two districts, while relative humidity showed negative significant at Mansoura district in the last season. On the other hand, the data cleared highly significant correlation between temperature and D. rapae during the two seasons at the two districts. Results indicated a highly negative significant between temperature and Aphidius sp at Mansoura district during two seasons. A significant negative correlation was obtained between the two parasitoids, D. rapae & Aphidius sp and A. nerii during two seasons at two districts. The parasitoid, D. rapae accepted the stages of oleander aphid, A. nerii, with average number of mummies per female parasitoid 64.2. Results indicated insignificant effect on incubation period of eggs, larval and pupal durations between the two parasitoids, D. rapae and Aphidius sp., but the total developmental period of two parasitoids had a significant effect on A. nerii, the averages were 19.38±0.57 and 22.09±0.54 with D. rapae and Aphidius sp., respectively. The work showed that leaf -arrival time decreased with increasing host density. Meanwhile, the first sting-time, numbers of oviposition and mummies increased with increasing host density.

Se determinó el efecto de extractos de neem en el comportamiento de alimentación y la transmisión del Virus de la Mancha Anular del Papayo (PRSV-p) por Aphis nerii. Se evaluó un extracto acuoso al 10% de semillas de neem sin escarificar, y un testigo con agua, asperjados en plantas de papayo en el laboratorio. El comportamiento de alimentación del áfido se estudió en dos fases: exploratoria (0 hasta 3 min) y de alimentación (>3 hasta 20 min). Se determinó la mortalidad de áfidos a las 24 h. El análisis de la transmisión del virus se realizó con base en pruebas de ELISA. No se detectaron diferencias significativas (p > 0.05) en cuanto al comportamiento de alimentación para la fase exploratoria, lo que indica que el neem no afecta la búsqueda y el probado inicial del áfido sobre la planta. En cambio, un número significativamente mayor de áfidos (p < 0.05) dejó de alimentarse en la fase >3 hasta 20 min. Además, la mortalidad de áfidos es mayor (p < 0.05) en el tratamiento con plantas asperjadas con neem (37% vs. 10%). No se encontraron diferencias significativas (p > 0.05) en la transmisión del PRSV-p por Aphis nerii, lo que indica que los extractos acuosos de semillas de neem no impiden la transmisión del virus.

Non-Mendelian maternal effects, the effects of maternal phenotype or environment on offspring phenotype, have been documented in numerous taxa. By affecting offspring vital rates (birth, death, and movement), maternal effects have the potential to influence population dynamics. However, relatively few studies have directly linked maternal phenotype or environment to offspring vital rates. Additionally, even fewer studies have compared the magnitude of across-generation effects (i.e. maternal effects) to within-generation effects. 2. Because of their telescoping generations, aphids can be strongly influenced by maternal effects. The effects of maternal density and maternal host-plant species on offspring survival, fecundity, and alate formation were investigated experimentally in Aphis nerii , the milkweed - oleander aphid. 3. Additionally, the relative strength of maternal effects were compared with those operating within a generation. Therefore, in another set of experiments, the effects of current density and host-plant species (within-generation effects) on aphid vital rates were examined. 4. While maternal effects were present, within-generation effects were much stronger and more strongly influenced aphid vital rates. Within a generation, aphids exhibited density-dependent survival, fecundity, and alate formation and these effects varied among host-plant species. 5. These results indicate that while maternal effects have the potential to affect population dynamics, this potential is not always met. Additionally, the current environment, not the environment of previous generations, more strongly impacts population dynamics.

The objective of this work was to record the diversity of parasitoid of two aphid species, Brevicoryne brassicae L. and Aphis nerii Boyer de Fonscolombe in a site at Uberlândia, MG, and the relationship between parasitoid size and their mummies size, with reference to the host species. B. brassicae were collected on kale (Brassica oleracea L. var. acephala D.C.) and A nerii on milkweed (Asclepias curassavica L.). Samplings were made monthly from May, 1999 to May, 2000 in two experimental gardens. Morphometric measurements for both aphids and parasitoids were simplified by PCA analysis to achieve a multivariate size index. The parasitic Hymenoptera species associated with A. nerii were also found as parasitoids of B. brassicae, but with distinctive relative frequencies. Diaeretiella rapae (M'Intoch) (93.2%), Aphidius colemani Viereck (4.5%) and Lysiphlebus testaceipes (Cresson) (2.3%) were the parasitoids obtained from B. brassicae. Hyperparasitoids associated with these parasitoids were Alloxysta fuscicornis (Ashmead) (57.8%), Syrphophagus aphidivorus (Mayr) (25.1%) and Pachyneuron sp. (17.1%). The parasitoids found in A. nerii were: L. testaceipes (96.1%), A. colemani (3.9%) and the hyperparasitoids Pachyneuron sp. (85.2%) and S. aphidivorus (14.8%). Parasitoid size was correlated with mummy size for both A. nerii and B. brassicae. S. aphidivorus from A. nerii were significantly larger than those from B. brassicae. However, such differences were not detected for L. testaceipes, A. colemani or for Pachyneuron. Mummies of A. nerii were significantly larger than those of B. brassicae. No sexual dimorphism for size was detected.

El afido de la adelfa, Aphis nerii Boyer de Fonscolombe, es una de las plagas mas comunes de plantas ornamentales en las familias Apocynaceae y Sclepiadaceae y tiene distribucion mundial, ha sido responsable de la mortalidad de un gran numero de arbustos de adelfa (Nerium oleander L.) cada ano. En este estudio se investigo la actividad insecticida de nanoparticulas de Ag contra A. nerii. Nanoparticulas de Ag y Ag-Zn fueron sintetizadas a traves de un metodo solvotermico, y con ellas se prepararon soluciones insecticidas de diferentes concentraciones y se probaron contra A. nerii. Con fines de comparacion, tambien se uso imidacloprid como un insecticida convencional. En los experimentos, el valor LC50 para imidacloprid, nanoparticulas de Ag y Ag-Zn se calculo como 0.13 μL mL-1, 424.67 mg mL-1, y 539.46 mg mL-1, respectivamente. El resultado mostro que nanoparticulas de Ag pueden ser usadas como una herramienta valiosa en programas de manejo de plagas de A. nerii. Adicionalmente, el estudio mostro que 1 μL mL1 imidacloprid y 700 mg mL-1 de nanoparticulas tuvieron el mayor efecto en mortalidad de los insectos.

The prevalent way aphids accomplish colony defense against natural enemies is a mutualistic relationship with ants or the occurrence of a specialised soldier caste typcial for eusocial aphids, or even both. Despite a group-living life style of those aphid species lacking these defense lines, communal defense against natural predators has not yet been observed there. Individuals of Aphis nerii (Oleander aphid) and Uroleucon hypochoeridis, an aphid species feeding on Hypochoeris radicata (hairy cat's ear), show a behavioral response to visual stimulation in the form of spinning or twitching, which is often accompanied by coordinated kicks executed with hind legs. Interestingly, this behaviour is highly synchronized among members of a colony and repetitive visual stimulation caused strong habituation. Observations of natural aphid colonies revealed that a collective twitching and kicking response (CTKR) was frequently evoked during oviposition attempts of the parasitoid wasp Aphidius colemani and during attacks of aphidophagous larvae. CTKR effectively interrupted oviposition attempts of this parasitoid wasp and even repelled this parasitoid from colonies after evoking consecutive CTKRs. In contrast, solitary feeding A. nerii individuals were not able to successfully repel this parasitoid wasp. In addition, CTKR was also evoked through gentle substrate vibrations. Laser vibrometry of the substrate revealed twitching-associated vibrations that form a train of sharp acceleration peaks in the course of a CTKR. This suggests that visual signals in combination with twitching-related substrate vibrations may play an important role in synchronising defense among members of a colony. In both aphid species collective defense in encounters with different natural enemies was executed in a stereotypical way and was similar to CTKR evoked through visual stimulation. This cooperative defense behavior provides an example of a surprising sociality that can be found in some aphid species that are not expected to be social at all.

キョウチクトウアブラムシの京都における生活環およびその天敵昆虫群構成を明らかにするため,京都市内2か所のキョウチクトウで1990年から3年間サンプリングおよび発生状況調査をおこない,次の結果を得た。1) キョウチクトウアブラムシは,京都において不完全生活環を全うできる。有翅虫は5月上旬に分散をはじめ,その後6月上旬,8月上旬,9月にそれぞれ発生のピークがみられた。秋にキョウチクトウが剪定され,新梢が伸長した場合にはその個体群は冬期にも高密度で推移したが,新梢が伸長しない場合には低密度で推移し,死滅することもあった。2月から3月の厳寒期には,胎生雌は増殖を停止し,その体色は鮮やかな黄色から乳濁色に変化した。越冬虫は3月末から増殖を再開し,4月末に最初の有翅虫が出現した。2) 本種の天敵昆虫として,次の15種を確認した。テントウムシ3種,ヒラタアブ4種,アブラコバエ1種,クサカゲロウ3種,ヒメカゲロウ1種,アブラバチ2種,ツヤコバチ1種。5月下旬から9月中旬までは,ダンダラテントウ(幼虫・成虫)の個体数が最も多く,その捕食が,アブラムシ個体群に対する重要な抑制要因であると考えられた。9月下旬以降はヒラタアブ(幼虫)や捕食寄生バチ類が活動したが,アブラムシの発生量を低下させることはできなかった。キョウチクトウアブラムシの毒性が,その天敵昆虫に及ぼす影響について考察した。

Penetration of the stems and leaves ofGomphocarpus physocarpus (E.Mey) by the aphid,Aphis nerii (B. de F.) was studied with light and phase microscopes. Penetration of the epidermis and ground tissues was largely intercellular, that of the phloem tissues partly intercellular and in part intracellular. In the large majority of penetrations the external phloem was bypassed, the stylet tracks terminating in the sieve tubes of the internal phloem. Of 75 pairs of stylet tips encountered in presumably functional sieve tubes 73 were lodged in sieve tubes of the internal phloem. This confirms observations of a preliminary study which indicated thatA. nerii feeds preferentially on sieve tubes of the internal phloem. A satisfactory explanation of this preferential feeding has yet to be provided.

In the wing dimorphic milkweed-oleander aphid,Aphis nerii, winged aphids begin reproducing about 1.5 days after wingless aphids. The longer maturation period is primarily due to slower development since even adult eclosion by winged aphids takes place after wingless aphids begin reproducing. The delay is not due to a post-eclosion, pre-reproductive flight since, beginning with the fourth instar, larval winged aphids were reared at a density of one per plant and the vast majority were not stimulated to fly under such low-density conditions. Thus, the ability to fly incurs a fitness cost in terms of delayed reproduction, irrespective of whether flight actually occurs. We did not observe a difference between morphs for lifetime fecundity, even though wingless aphids have larger abdomens than winged aphids and for both morphs there is a significant correlation between abdomen width and fecundity. Offspring produced by wingless aphids over the first four days of reproduction are larger than those produced by winged aphids, and the size difference at birth is maintained into adulthood. However, there are no differences in life history traits between these offspring, including maturation period and lifetime fecundity. Thus, reduced body size does not increase the cost of being able to fly, at least under the conditions of these experiments. The cost of being able to fly in this species should favor reduced production of winged individuals in populations that exploit more permanent host plants.

Penetration of the phloem of young and mature leaves ofNerium oleander by stylets of the aphid,Aphis nerii was studied with light, phase and differential interference contrast microscopes. Two of five pairs of stylet tips encountered in young leaves and eleven of sixteen pairs encountered in mature leaves were lodged in sieve tubes of the adaxial phloem. In young leaves, the majority of penetrations originated from the abaxial epidermis; conversely, the majority of penetrations in mature leaves originated from the adaxial epidermis. In all instances, penetration of the epidermis, ground tissue and phloem was largely intercellular.

Populations of the milkweed-oleander aphid,Aphis nerii, were sampled in California, Iowa and Puerto Rico. Among these localities the aphid's host plants differ greatly in permanence. I compared populations for migratory potential, measured as the proportion of winged offspring produced in response to being crowded, and for life history and morphometric traits of the subsequent adult winged aphids. I predicted a negative correlation between degree of host plant permanence and migratory potential. As predicted, aphids from Iowa, where migration on to temporary hosts must occur each year, produce a greater proportion of winged offspring (37.7%) than those from California (25.7%) or Puerto Rico (31.6%) where hosts are more permanent. However, hosts in Puerto Rico appear to be more permanent than those in California, yet the difference between populations for migratory potential was opposite to that predicted. Within California the prediction again held: aphids collected from the most impermanent sites produce the greatest proportion of winged offspring. There were no population differences for any life history or morphometric traits of winged aphids that are important contributors to fitness or migratory ability such as time to reproductive maturity, fecundity or wing length. Nor did any traits covary with migratory potential. Thus, there does not appear to be an association of life history and morphology with migratory potential that could enhance the colonizing ability of migrant aphids. I was unable to detect population differentiation for life history and morphology even though there is ample genetic variation within populations on which selection could act and an absence of constraints arising from genetic correlations that could prevent appropriate evolution of traits within populations. The exploitation of temporary host plants therefore occurs by an increase in the number of colonists produced and not by change in life history or morphology of those colonists.

This paper deals with the oleander aphid, Aphis nerii Boyer de Fonscolombe, 1841, a very common aphid at Piracicaba (State of São Paulo, Brazil).

Penetration of the stems ofAraujia sericofera, Asclepias curassavica, Cynanchum ellipticum andSarcostemma viminale by stylets of the aphidAphis nerii was studied with light and differential interference contrast microscopes. Of a total of 118 stylets and 446 stylet tracks observed in cross-sections of stems of the fourAsclepiadaceae, 97 stylets and 372 stylet tracks terminated within the internal primary phloem. Of the remainder, 15 stylets and 74 tracks terminated within the external primary phloem. 22 stylets and 179 of the stylet tracks penetrated the external phloem on the way to the internal phloem. Of these, only four stylets and 32 of the stylet tracks showed signs of attempted probes of the external phloem. It is suggested thatAphis nerii may obtain not only its essential food requirements but also cardiac glycosides as a basis for chemical aposematism.

The oleander aphid, Aphis nerii Boyer de Fonscolombe, sometimes called the milkweed aphid, is a common pest of several important ornamental plants in the families Apocynaceae and Asclepiadaceae. This bright yellow aphid with black appendages is commonly found in Florida feeding on oleander, Nerium oleander, milkweeds, such as butterfly weed, Asclepias tuberosa, and scarlet milkweed, Asclepias curassavica, and wax plant, Hoya carnosa. This document is EENY-247, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: November, 2001. EENY247/IN520: Oleander Aphid, Aphis nerii Boyer de Fonscolombe (Insecta: Hemiptera: Aphididae) (ufl.edu)

Cardiac glycosides were found in the aposematic aphid Aphis nerii fed on both Nerium oleander and Asclepias curassavica. The absence of oleandrin and calactin in the body tissues of this insect suggests they are absent from the phloem on which the aphids are believed to feed.

Parasitoids used as biological control agents often parasitize more than a single host species and these hosts tend to vary in suitability for offspring development. The population dynamics of parasitoids and hosts may be altered by these interactions, with outcomes dependent on the levels of suitability and acceptance of both host species. Parasitism of individuals of an unsuitable host species may indirectly increase populations of a suitable host species if eggs laid into unsuitable hosts do not develop into adult parasitoids. In this case, the unsuitable host is acting as an egg sink for parasitoids and this can reduce parasitism of suitable hosts under conditions of egg limitation. We studied parasitoid‐mediated indirect interactions between two aphid hosts, Aphis glycines (the soybean aphid) and A. nerii (the milkweed, or oleander aphid), sharing the parasitoid Aphelinus certus. While both of these aphid species are accepted by A. certus, soybean aphid is a much more suitable host than milkweed aphid is. We observed a drastic reduction of parasitoid offspring production (45%) on the suitable host in the presence of the unsuitable host in microcosm assays. Aphelinus certus females laid eggs into the unsuitable hosts (Aphis nerii) in the presence of the suitable host leading to egg and/or time limitation and reduced fitness. The impact of these interactions on the equilibrium population sizes of the three interacting species was analyzed using a consumer–resource modeling approach. Both the results from the laboratory experiment and the modeling approaches identified apparent predation between soybean aphid and milkweed aphid, in which milkweed aphid acts as a sink for parasitoid eggs leading to an increase in the soybean aphid population. The presence of soybean aphids had the opposite effect on milkweed aphid populations as it supported increases in parasitoid abundance and thus reduced the fitness and abundance of this aphid species., We investigated indirect interactions that can occur when a single parasitoid species attacks two aphid species that differ in their suitability for parasitism. Laboratory studies showed that the presence of unsuitable hosts indirectly increased populations of suitable hosts through an egg sink experienced by the shared parasitoid, and a parameterized population model confirmed and extended this result to longer time scales. These results show how such indirect effects can affect community structure and affect biological control interactions.

Stage-specific functional response of Coccinella septempunctata L. was evaluated under laboratory conditions to varying densities (10, 20, 40, 60, 80, 100, 120, 150 and 200) of Lipaphis erysimi (Kaltenbach)., Diuraphis noxia Kurdjumov. and Aphis nerii Fonscolombe. Logistic regression analysis of all life stages of C. septempunctata exhibited negative linear-coefficient (P1), confirming a curvilinear type II functional response against all the tested aphid species. The fourth instar of C. septempunctata, in comparison to other stages, exhibited the highest predation activity against D. noxia and A. nerii, with an attack rate (a) of 7.31 h-1, 5.79 h-1 and handling time (Th) of 0.0106 h, 0.0092 h, respectively. Under different densities of L. erysimi, adult females of C. septempunctata exhibited the highest predation activity with an a of 7.58 h-1, followed by the fourth instar with a of 7.31 h-1 and adult male 6.60 h-1 and Th of 0.0066 h, 0.0079 h and 0.0092 h, respectively. The attack rate and handling time estimated for different stages of C. septempunctata showed that the fourth instar of C. septempunctata had the highest attack rate, whereas handling time was variable. Adult females of C. septempunctata showed minimum handling time (0.00013 h) in most of the cases. Our results suggest that the fourth instar larvae and adult female of C. septempunctata are efficient predator for the biological control of L. erysimi, D. noxia and A. nerii. Further field-based studies are needed to confirm this hypothesis.

Plants use volatile organic compounds (VOCs) to cue natural enemies to their herbivore prey on plants. Simultaneously, herbivores utilize volatile cues to identify appropriate hosts. Despite extensive efforts to understand sources of variation in plant communication by VOCs, we lack an understanding of how ubiquitous belowground mutualists, such as arbuscular mycorrhizal fungi (AMF), influence plant VOC emissions. In a full factorial experiment, we subjected plants of two milkweed (Asclepias) species under three levels of AMF availability to damage by aphids (Aphis nerii). We then measured plant headspace volatiles and chemical defenses (cardenolides) and compared these to VOCs emitted and cardenolides produced by plants without herbivores. We found that AMF have plant species-specific effects on constitutive and aphid-induced VOC emissions. High AMF availability increased emissions of total VOCs, two green leaf volatiles (3-hexenyl acetate and hexyl acetate), and methyl salicylate in A. curassavica, but did not affect emissions in A. incarnata. In contrast, aphids consistently increased emissions of 6-methyl-5-hepten-2-one and benzeneacetaldehyde in both species, independent of AMF availability. Both high AMF availability and aphids alone suppressed emissions of individual terpenes. However, aphid damage on plants under high AMF availability increased, or did not affect, emissions of those terpenes. Lastly, aphid feeding suppressed cardenolide concentrations only in A. curassavica, and AMF did not affect cardenolides in either plant species. Our findings suggest that by altering milkweed VOC profiles, AMF may affect both herbivore performance and natural enemy attraction.

Coccinellids are common predators of aphids, including Aphis nerii, Diuraphis noxia and Lipaphis erysimi. The zigzag ladybird beetle, Menochilus sexmaculatus, is an effective predator against various aphid species. In the present study, different stages of M. sexmaculatus were evaluated for their functional response against A. nerii, D. noxia, and L. erysimi. Functional response at different densities of aphids was calculated over a period of 24h at 25 ± 5 °C and 65 ± 5% RH. Roger's Random Predator equation was used to calculate the parameters of a functional response. All the predatory stages showed Type II functional response. Attack rate was highest in the fourth instar for all aphid species (4.5171, 2.5894 and 2.8853, respectively), while the shortest handling time of the fourth instar was recorded for A. nerii (0.0175h) and L. erysimi (0.0159h). In the case of D. noxia, the shortest handling time was observed in the first instar (0.0175h). The fourth instar of M. sexmaculatus consumed more prey, followed by the third instar. These results indicate that the fourth instar of M. sexmaculatus was the most effective stage against its prey, followed by the third instar, adult females and males. Further field experiments must be carried out to corroborate the efficacy of these predatory beetles under natural conditions.

The use of chemical insecticides has had several side-effects, such as environmental contamination, foodborne residues, and human health threats. The utilization of plant-derived essential oils as efficient bio-rational agents has been acknowledged in pest management strategies. In the present study, the fumigant toxicity of essential oil isolated from Satureja intermedia was assessed against cosmopolitan stored-product insect pests: Trogoderma granarium Everts (khapra beetle), Rhyzopertha dominica (Fabricius) (lesser grain borer), Tribolium castaneum (Herbst) (red flour beetle), and Oryzaephilus surinamensis (L.) (saw-toothed grain beetle). The essential oil had significant fumigant toxicity against tested insects, which positively depended on essential oil concentrations and the exposure times. Comparative contact toxicity of S. intermedia essential oil was measured against Aphis nerii Boyer de Fonscolombe (oleander aphid) and its predator Coccinella septempunctata L. (seven-spot ladybird). Adult females of A. nerii were more susceptible to the contact toxicity than the C. septempunctata adults. The dominant compounds in the essential oil of S. intermedia were thymol (48.1%), carvacrol (11.8%), p-cymene (8.1%), and &gamma, terpinene (8.1%). The high fumigant toxicity against four major stored-product insect pests, the significant aphidicidal effect on A. nerii, and relative safety to the general predator C. septempunctata make terpene-rich S. intermedia essential oil a potential candidate for use as a plant-based alternative to the detrimental synthetic insecticides.

Plants link interactions between aboveground and belowground organisms. Herbivore-induced changes in plant chemistry are hypothesized to impact entire food webs by changing the strength of trophic cascades. Yet, few studies have explored how belowground herbivores affect the behaviors of generalist predators, nor how such changes may act through diverse changes to the plant metabolome. Using a factorial experiment, we tested whether herbivory by root-knot nematodes (Meloidogyne incognita) affected the aboveground interaction among milkweed plants (Asclepias fascicularis or Asclepias speciosa), oleander aphids (Aphis nerii), and aphid-tending ants (Linepithema humile). We quantified the behaviors of aphid-tending ants, and we measured the effects of herbivore treatments on aphid densities and on phytochemistry. Unexpectedly, ants tended aphids primarily on the leaves of uninfected plants, whereas ants tended aphids primarily at the base of the stem of nematode-infected plants. In nematode-infected plants, aphids excreted more sugar per capita in their ant-attracting honeydew. Additionally, although plant chemistry was species-specific, nematode infection generally decreased the richness of plant secondary metabolites while acting as a protein sink in the roots. Path analysis indicated that the ants' behavioral change was driven in part by indirect effects of nematodes acting through changes in plant chemistry. We conclude that belowground herbivores can affect the behaviors of aboveground generalist ant predators by multiple paths, including changes in phytochemistry, which may affect the attractiveness of aphid honeydew rewards.

BACKGROUND Flowers are admirable in scenic good looks and artistic beautification. These are also playing necessary roles in therapeutic preparations. Aphid is an important sucking pest of various flowers in ornamental territories and it is generally controlled by predators, so it was necessary to evaluate which aphid species affect the predator more or less. MATERIALS AND METHODS Biocontrol agent Coccinella septempunctata was used against cosmos aphid (Aphis spiraecola, rose aphid (Macrosiphum rosea), gul e ashrafi aphid (Aphis fabae), kaner aphid (Aphis nerii), chandni aphid (Sitobion avenae), dahlia aphid (Myzus persicae) and annual chrysanthemum aphid (Macrosiphoniella sanborni). RESULTS The grub of C. septempunctata consumed 283.8±9.04 M. rosea, 487.7±12.6 M. sanborni, 432.75±16.02 A. spiraecola, 478.2±8.07 A. fabae, 552.3±9.04 M. persicae, 142±1.32 A. nerii and 498.5±13.09 S. avenae in its whole larval life. The M. persicae and M. rosea consuming grubs showed 100% adult emergence while, M. sanborni, A. spiraecola, A. fabae and S. avenae showed 96.58, 89.02, 94.78 and 75.45% adult emergence, respectively. CONCLUSION The C. septempunctata has significant predatory potential against A. spiraecola, M. rosea, A. fabae, S. avenae, M. persicae and M. sanborni except A. nerii. Thus, further studies are needed to find out alternate predator to control A. nerii on ornamentals.

1.Specialized insect herbivores commonly co‐opt plant defences for protection against predators, but the costs, benefits, and mechanisms of sequestration are poorly understood. 2.We quantified sequestration of toxic cardenolides by the specialist aphid Aphis nerii when reared on four closely related milkweed (Asclepias) species with >20‐fold variation in cardenolide content, and in the presence or absence of generalist ladybug predators. 3.Increasing concentrations of apolar plant cardenolides increased sequestered amounts in aphids. High concentrations in plants impaired aphid population growth, but also reduced the top‐down effects of predators. An in vitro enzymatic assay of total cardenolides in aphid bodies using the cardenolides’ target (animal Na+/K+‐ATPase) revealed that the subset of sequestered cardenolides is disproportionally more toxic than cardenolides in leaves. 4.All aphids accumulated two cardenolides not present in their host plant, even on plants with very low foliar cardenolide concentrations. Sequestration of potent cardenolides by Aphis nerii thus involves passive, concentration‐dependent uptake from the host plant, as well as a presumably more active mechanism of modification and up‐concentration of plant cardenolides. 5.The concentration of toxins in the host plant thus not only determines the negative impacts on growth and performance of an aphid, but also the ease and efficiency by which toxins are sequestered for the aphid's defence, making the costs and benefits of plant toxins highly context‐dependent for both the plant and the herbivore. Therefore, variation in plant toxins is of central importance for co‐evolutionary plant‐insect interactions, particularly in environments with variable predator pressure.

International audience; Honeydew i.e., the sugar-rich excretion of phloem-sap feeders, is the most available sugar source in agroeco-systems which enables parasitoids to increase their fitness. For the parasitoids of honeydew-producing insects, honeydew is associated with host presence, suggesting that parasitoids can find carbohydrate sources and hosts at the same place. Hence, these parasitoids may have evolved to efficiently use the honeydew produced by their main hosts as a carbohydrate source. In this context, we assessed the relationship between the adult fitness (in terms of longevity and fecundity) of the aphid parasitoid Aphelinus abdominalis (which prefer attack aphid species belonging to the Macrosiphini tribe), fed on honeydew produced by 19 different plant-aphid combinations, and parasitoid preference (i.e., the choice of female to oviposit) and ability to produce offspring in these combinations. Honeydew quality was modulated by both the plant and aphid host species. The honeydew produced by eight aphid species (e.g., Macrosiphum euphorbiae and Aphis craccivora) resulted in high parasitoid longevity (same longevity as the honey-fed positive control) and an increase in egg load between 24 and 48 h, compared to the negative control (fed only water). In contrast, nine aphid species (e.g., Brevicoryne brassicae and Aphis nerii) excreted low-quality honeydew that did not increase parasitoid longevity or egg load (similar to the negative control water-fed parasitoids). There was no relationship between A. abdominalis adult fitness when fed various honeydews and its preference as well as its ability to produce offspring in the hosts producing these honeydews. Several hypotheses that may explain this lack of relationship are discussed.

Ladybird beetle, Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae), is biological control agent that predate the different aphid species. Both adults and larval stage of M. sexmaculatus feed on aphid species. In this experiment Life table and predation data were collected for M. sexmaculatus feed on four different aphid species Lipaphis erysimi, Myzus persicae, Aphis nerii and Diuraphis noxia. This experiment was conducted under laboratory conditions at 25±2°C, 60±5% RH and L14: D10 h. Different numbers of aphid were provided as a pray in petri dish. The pre-adult development duration of M. sexmaculatus was maximum when fed on M. persicae (12.18 d) and minimum on D. noxia (10.64 d). Similarly, male and female duration was maximum on M. persicae (26.7 d), minimum on L. erysimi (23.67 d) in male and in female maximum on D. noxia (28.00 d), minimum on A. nerii (24.33 d). Net reproductive rate (Ro) range from 117.9 on L. erysimi to 99.55 on M. persicae and intrinsic rate of increase (r) range was 0.21197 d−1 on A. nerii to 0.021559 d−1 on D. noxia. The finite rate of increase (λ) range was 1.240592 d−1 on D. noxia to 1.204918 d−1 on M. persicae, the mean of generation (T) range was 24.68 d−1 on M. persicae to 22.476 d−1 on A. nerii, similarly, the gross reproductive rate (GRR) range was 172.2 d−1 on D. noxia to 115.02 d−1 on M. persicae and Fecundity (F) eggs per female range was 316.8 on D. noxia to 199.1 on M. persicae. In present Study, age-stage two-sex life table gives complete understanding of predator biological aspects against different aphid species. This study will help us to improve mass rearing and use of M. sexmaculatus in biological control of aphids.

Studies were carried out in the Arab Republic of Egypt to study certain aphid species infestation, their associated parasitoids on Cabbage, Cauliflower, faba bean, oleander plant (Dafla), cucumber, corn and cowpea plants. Survey and seasonal abundance of the aphid species Brevicoryne brassicae L., Aphis craccivora (Koch), Aphis nerii Fonsecolombe., Hyalopterus pruni (Geoffroy), Aphis gossypii Glover, Rhopalosiphum maidis Fitch Rhopalosiphum padi L. and Hypermoyzus lactucae L. and its parasitoids were studied. Obtained results of the study showed that Diaeretiella rapae (M’Intosh) was the dominant parasitoid on aphid species. Longevity was affected by temperature and food but the sex ratio was not affect by host species. The behavior of this parasitoid at varying host densities was also studied. Result showed a decrease of host-searching and first sting times with increasing host density but number of sting and number of mummies increased as host density increases. The obtained results evaluated the role of the parasitoid D. rapae in controlling B. brassicae and A. craccivora under greenhouses and field conditions. Results emphasized that the efficiency of this aphid parasitoid had been decreased with the highly population density of aphids. It may be concluded that when this aphid parasitoid used as biological control agents against B. brassicae and A. craccivora should be used with low host density.

Insects have been challenged by plant secondary metabolites throughout their evolutionary history. An important mechanism thought to promote insecticide resistance is the ability of insects to use preexisting detoxification systems originally evolved for tolerance of plant defenses. However, it remains unclear what level of convergence exists in metabolic mechanisms employed against various natural and xenobiotic chemicals? How do transcriptomic responses to these stressors change in response to novel and long-term exposure? We employ an experimental evolution approach in a milkweed- specialist aphid (Aphis nerii) model to test the effects of a more toxic host plant species and two insecticides commonly used in rotation in agriculture (a neonicotinoid, Imidacloprid, and a general homopteran blocker, Pymetrozine) on aphid gene expression and fitness over multiple generations of selection. Aphids were selected on three stress treatments: a toxic host plant species and two pesticides (Imidacloprid and Pymetrozine) for five generations. Whole transcriptome gene expression changes and changes in development time and fecundity were compared at generations one and five. While there were no consistent fitness costs or benefits to long-term exposure, exposure to stress is associated with increased transcriptional plasticity and changes in genes associated with the metabolism of secondary metabolites as well as genes important in transcription, translation, and post-translation processes.

The aim of this work was to examine, both in the field and in the laboratory, ecological aspects of selected plant–aphid–parasitoid interactions to evaluate their potential for the open rearing of the parasitoid Lysiphlebus testaceipes (Cresson) (Hymenoptera: Aphidiinae) for the control of Aphis craccivora (Koch) (Hemiptera: Aphididae) in alfalfa agroecosystems. To this end quantitative samplings of parasitoids and aphids were made fortnightly in three alfalfa crop fields and their spontaneously vegetated edges, in Rafaela (Santa Fe, Argentina), during three years (2009–2011). Three sink webs based on L.testaceipes, on a per-year basis, were constructed to assess the strength of the interactions established by aphids and parasitoids, the host ranges of alternative aphid species, and the tendencies in parasitoid host use across years. In the laboratory, emergence rates, parasitism rates, larval and pupal development times, and adult lifespan of L. testaceipes were analyzed by means of choice tests, including the alternative and the target aphid species in the assays. About 84 % of adults of L. testaceipes obtained in the samples came from Aphis nerii (Boyer de Fonscolombe), an innocuous aphid species only associated with plants of the genus Araujia Brotero (Apocynaceae). Based on our results, the system proposed has many features that support its feasibility to be used as an open rearing system of L. testaceipes: unrisky alternative aphid, easy reproduction of the banker plant and similar suitability of innocuous and pest aphid species for the parasitoid to oviposit and complete their development without noticeably preference for specific hosts. Fil: Zumoffen, Leticia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina Fil: Tavella, Julia Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Signorini, Marcelo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina Fil: Salvo, Silvia Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina

To understand the entomofauna and potential as alternate hosts for natural enemies of Asclepias curassavica L., a study was established between 2012 and 2013 at Emiliano Zapata, Villamar, Michoacan, Mexico. Fifty plants of A. curassavica were planted in pots, and phytophagous arthropods, predators, parasitoids, and aphid parasitism were sampled and recorded each week. Ten species of phytophagous arthropods were identified, including Aphis nerii B. de F., Danaus plexippus L, Oncopeltus fasciatus Dallas, Lygaeus reclivatus Say, and Liriomyza asclepiadis Spencer. Seven species of parasitoids and 14 predators were recorded. Trichogramma pretiosum Riley was an important parasitoid in eggs of D. plexippus, while Lysiphlebus testaceipes (Cresson) was the most important parasitoid in A. nerii. The most important predators were Pseudodorus clavatus (Fabricius), Leucopis sp. (both 14.97%), Chrysopidae (21.43%), and Coccinellidae families; Cicloneda sanguinea L. (55.22%) and Scymnus sp. (3.84%) were the most important species. Holobus sp. preyed on the phytophagous mite, Eotetranychus typhae Tuttle, Baker and Abbatiello. E. typhae was recorded for the first time on A. curassavica. The wide diversity of natural enemies associated with specialized phytophagous arthropods of A. curassavica suggested potential of the plant to be deliberately used as a reservoir of alternate hosts of natural enemies, which could eventually regulate abundance of arthropods in agro-ecosystems.

The Ord River Irrigation Area (ORIA) produces annual crops during the dry season (April to October), and perennial crops all-year-round, and is located in tropical northwestern Australia. Sandalwood plantations cover 50 % of the ORIA’s cropping area. Aphids cause major crop losses through transmission of viruses causing debilitating diseases and direct feeding damage. During 2016–2017, in both dry and wet seasons a total of 3320 leaf samples were collected from diverse types of sites on cultivated and uncultivated land and 1248 (38 %) of them were from aphid-colonized plants. In addition, aphids were found at 236 of 355 sampling sites. The 62 plant species sampled came from 23 families 19 of which contained aphid-colonized species. Aphid hosts included introduced weeds, Australian native plants, and volunteer or planted crop plants. Six aphid species were identified by light microscopy and CO1 gene sequencing, but there was no within species nucleotide sequence diversity. Aphis nerii, Hysteroneura setariae, Rhopalosiphum maidis and Schoutedenia ralumensis each colonized 1–3 plant species from a single plant family. A. craccivora colonized 14 species in five plant families. A. gossypii was the most polyphagous species colonizing 19 species in 11 plant families. A. gossypii, A. craccivora, A. nerii and S. ralumensis were found in both wet and dry seasons. Because of A. craccivora’s prevalence and high incidences on understory weeds and host trees, sandalwood plantations were important reservoirs for aphid spread to wild and crop plant hosts growing in cultivated and uncultivated land. Alternative hosts growing in rural bushland, irrigation channel banks, vacant or fallow land, and orchard plantation understories also constituted significant aphid reservoirs. This study provides new knowledge of the ecology of aphid vector species not only in the ORIA but also in tropical northern Australia generally. It represents one of relatively few investigations on aphid ecology in tropical environments worldwide.

Passive “vector” plants can harbor insect viruses without supporting their replication and may have epidemiological consequences. We report complete sequence of Aphid lethal paralysis virus (ALPV, Cripavirus, Dicistroviridae) from small RNA sequencing of a new passive “vector” plant, Cestrum elegans in Turkey using de novo assembly and annotating of contigs. Its genome is 9837 nt in length which encodes for 2 ORFs (including an intergenic untranslated region (IGR) of 196 nt) flanked by a 525 nt 5′ UTR and a 596 nt 3′ UTR. Multiple alignment and phylogenetic analysis showed that the isolate shares highest identity with ALPV-An (JX480861) isolated from oleander aphid, Aphis nerii and was placed into the same clade with other isolates of passive “vector” plants comprising cucumber and maize isolates.

We investigated prey preference of adult male and female Propylea dissecta (Mulsant) when fed on the aphids, Aphis craccivora and Lipaphis erysimi, which sequester toxic allelochemicals from their host plants. Both the male and female adults of P. dissecta prefer to consume L. erysimi in most mixed diet treatments (cafeteria experiment). This was well supported by significantly high values of the β and C prey preference indices. However, when provided with these aphids separately, the adults showed no significant difference in aphid consumption, regardless of the species of aphid and sex of the adult ladybird. We conclude that host plant allelochemicals/toxicants have a direct effect on prey preference of ladybirds. Host plant toxic constituents can alter the biochemical composition of the most preferred prey and make them the least preferred. Mixing two toxic similar diets can make one diet more suitable than the other.