Mean (± SEM) yield (kg/ha) in 2012.

<p>Wheat was planted on dates (A) 27^th November (B) 6^th December, (C) 16^th December. Control: no spray; MLE: spray of moringa leaf extract; MLE+NSE: spray of moringa leaf extract in combinaiton with neem seed extract; NSE-1: one spray of neem seed extract; I: spray of imidacloprid; I+MLE: spray of imidcloprid in combination with moringa leaf extract; NSE-2: two sprays of neem seed extract. Means on a given sowing date sharing common letters are not statistically different at <i>P</i> < 0.05 (Tukey’s HSD test).</p

Mean (± SEM) number of wheat aphids per plant in the growing season 2012–2013.

<p>Wheat was planted on dates (A) 27^th November (B) 6^th December, (C) 16^th December. Control: no spray; MLE: spray of moringa leaf extract; MLE+NSE: spray of moringa leaf extract in combinaiton with neem seed extract; NSE-1: one spray of neem seed extract; I: spray of imidacloprid; I+MLE: spray of imidcloprid in combination with moringa leaf extract; NSE-2: two sprays of neem seed extract. Means on a given sowing date sharing common letters are not statistically different at <i>P</i> < 0.05 (Tukey’s HSD test).</p

Total counts of wheat aphids and natural enemies observed in the control plots of wheat fields planted on 24^th November,27^th November and 3^rd December during the growing season of 2013.

<p>Total counts of wheat aphids and natural enemies observed in the control plots of wheat fields planted on 24^th November,27^th November and 3^rd December during the growing season of 2013.</p

Mean (± SEM) seasonal sum of predators and predator–prey ratios per plot from wheat fields planted at three different dates during the growing season of 2013–14.

<p>Mean (± SEM) seasonal sum of predators and predator–prey ratios per plot from wheat fields planted at three different dates during the growing season of 2013–14.</p

Effect of various treatments on shoot biomass, grains/spike and thousand grains weights per plot from wheat planted on different dates during 2013–14 wheat growing season.

<p>Effect of various treatments on shoot biomass, grains/spike and thousand grains weights per plot from wheat planted on different dates during 2013–14 wheat growing season.</p

Identification and Expression Analysis of Candidate Odorant-Binding Protein and Chemosensory Protein Genes by Antennal Transcriptome of <i>Sitobion avenae</i>

<div><p>Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) of aphids are thought to be responsible for the initial molecular interactions during olfaction that mediate detection of chemical signals. Analysis of the diversity of proteins involved comprises critical basic research work that will facilitate the development of sustainable pest control strategies. To help us better understand differences in the olfactory system between winged and wingless grain aphids, we constructed an antennal transcriptome from winged and wingless <i>Sitobion avenae</i> (Fabricius), one of the most serious pests of cereal fields worldwide. Among the 133,331 unigenes in the antennal assembly, 13 OBP and 5 CSP putative transcripts were identified with 6 OBP and 3 CSP sequences representing new <i>S</i>. <i>avenae</i> annotations. We used qPCR to examine the expression profile of these genes sets across <i>S</i>. <i>avenae</i> development and in various tissues. We found 7 SaveOBPs and 1 SaveCSP were specifically or significantly elevated in antennae compared with other tissues, and that some transcripts (<i>SaveOBP8</i>, <i>SaveCSP2</i> and <i>SaveCSP</i>5) were abundantly expressed in the legs of winged or wingless aphids. The expression levels of the SaveOBPs and SaveCSPs varied depending on the developmental stage. Possible physiological functions of these genes are discussed. Further molecular and functional studies of these olfactory related genes will explore their potential as novel targets for controlling <i>S</i>. <i>avenae</i>.</p></div

Phylogenetic tree of 167 OBPs from 21 hemipteran species.

<p>The tree was constructed using MEGA 5.0 with bootstrap support based on 1000 iterations. Aphid sequences are in red. Bug sequences are in blue. Planthopper sequences are in gray. Major clades for aphid OBPs are marked in a different color. Abbreviation for these aphid species: Save, <i>S</i>. <i>avenae</i>; Acra, <i>A</i>. <i>craccivora</i>; Psal, <i>P</i>. <i>salicis</i>; Brebr, <i>B</i>. <i>brassicae</i>; Apis, <i>A</i>. <i>pisum</i>; Dpla, <i>D</i>. <i>platanoidis</i>; Mper, <i>M</i>. <i>persicae</i>; Nrib, <i>N</i>. <i>ribisnigri</i>; Rpad, <i>R</i>. <i>padi</i>; Mvic, <i>M</i>. <i>viciae</i>; Tsal, <i>T</i>. <i>salignus</i>; Afab, <i>A</i>. <i>fabae</i>; Agos, <i>A</i>. <i>gossypii</i>; Mdir, <i>M</i>. <i>dirhodum</i>; Lery, <i>L</i>. <i>erysimi</i>; Agly, <i>A</i>. <i>glycines;</i> Aluc, <i>A</i>. <i>lucorum</i>; Alin, <i>A</i>. <i>lineolatus</i>; Llin, <i>L</i>. <i>lineolaris</i>; Nlug, <i>N</i>. <i>lugens</i>; Sfur, <i>S</i>. <i>furcifera</i>.</p

Alignment of amino acid sequences of the OBPs and CSPs in <i>S</i>. <i>avenae</i>.

<p>Sequences were aligned by Clustal Omega and edited using BoxShade. Black boxes show conserved cysteines. The conserved Cys residues are indicated. Shading represents sequence identity > 70%.</p

Tissue expression profiles of candidate OBPs in <i>S</i>. <i>avenae</i>.

<p>Fold-changes are relative to transcript levels in abdomens of winged adult aphids. Differences in mean transcript levels were compared using one-way ANOVA, followed by the least-significant difference (LSD) method. Bars with different letters indicate significant differences (<i>p</i> < 0.05). An: antennae, H: heads, T: thoraxes, Ab: abdomens, L: legs.</p

Expression profiles of <i>SaveOBP6 SaveOBP8</i> and <i>SaveOBP10</i> in different ages of <i>S</i>. <i>avenae</i>.

<p>Fold-changes are relative to transcript levels in 1st instar nymphs. Differences in mean transcript levels were compared using one-way ANOVA, followed by the least-significant difference (LSD) method. Bars with different letters indicate significant differences (<i>p</i> < 0.05). 1 In: 1st instar nymph; 2 In: 2nd instar nymph; 3W In: 3rd winged instar nymph; 3WL In: 3rd wingless instar nymph; 4W In: 4th winged instar nymph; 4WL In: 4th wingless instar nymph; W: winged adult; WL: wingless adult.</p