Pachyrhinus yasumatsui Kono et Morimoto is a major pest of Chinese jujube, which is widespread in northern China and causes severe economic losses in the jujube industry. Chemosensory genes play crucial roles in insect behaviors. Currently, little is known about chemosensory genes in P. yasumatsui. In the present study, antennal transcriptomes of female and male adult P. yasumatsui were annotated. In total, 113 genes involved in chemosensory functions were identified, including 41 odorant receptors, 28 odorant-binding proteins, 16 ionotropic receptors, 15 chemosensory proteins, 9 gustatory receptors, and 4 sensory neuron membrane proteins. Subsequently, the phylogenetic analyses of these olfactory-related proteins in P. yasumatsui were conducted using multiple sequence alignment. Furthermore, sex-specific expression levels of 113 genes were analyzed based on fragments per kilobase of transcript per million mapped reads (FPKM). Then, the quantitative real-time PCR (RT-qPCR) was used to quantify gene expression profiles of 28 P. yasumatsui OBPs (PyasOBPs) and 15 CSPs (PyasCSPs). The results revealed that 20 PyasOBPs and 13 PyasCSPs exhibited significantly higher expression in the antennae than in the bodies, suggesting that they might have functions in olfaction. Moreover, some OBPs and CSPs (PyasOBP6, PyasOBP7, PyasOBP16, PyasOBP21, and PyasCSP4) exhibited female-biased expression, indicating that they might take part in several female-specific behaviors. This study will promote the understanding of olfactory mechanism in P. yasumatsui, and our findings lay the groundwork for developing environmentally friendly pest management measures.

Odorant binding proteins (OBPs) play an important role in insect olfaction. The jujube bud weevil Pachyrhinus yasumatsui (Coleoptera: Curculionidae) is a major pest of Zizyphus jujuba in northern China. In the present study, based on the antennal transcriptome, an OBP gene of P. yasumatsui (PyasOBP2) was cloned by reverse transcription PCR (RT-PCR). Expression profile analyses by quantitative real-time PCR (qRT-PCR) revealed that PyasOBP2 was highly expressed in the antennae of both male and female P. yasumatsui adults, while its expression was negligible in other tissues. PyasOBP2 was prokaryotically expressed, and purified by Ni-NTA resin. The fluorescence competitive binding assays with 38 plant volatiles from Z. jujuba showed that PyasOBP2 could bind with a broad range of plant volatiles, and had strongest binding capacities to host-plant volatiles like ethyl butyrate (K_i = 3.02 μM), 2-methyl-1-phenylpropene (K_i = 4.61 μM) and dipentene (K_i = 5.99 μM). The three dimensional structure of PyasOBP2 was predicted by homology modeling, and the crystal structure of AgamOBP1 (PDB ID: 2erb) was used as a template. The molecular docking results indicated that the amino acid residue Phe114 of PyasOBP2 could form hydrogen bonds or hydrophobic interactions with some specific ligands, so this residue might play a key role in perception of host plant volatiles. Our results provide a basis for further investigation of potential functions of PyasOBP2, and development of efficient monitoring and integrated pest management strategies of P. yasumatsui.

Sympiezomias velatus (Chevrolat) (Coleoptera: Curculionidae) has caused serious damage on jujube trees (Ziziphus jujuba Mill) in northern China. Semiochemicals emerging from the host are essential in the process of insects identifying and localizing the host. The highly expressed odorant-binding protein 1 of S. velatus (SvelOBP1) was assumed to play a possible role in the recognition of host volatiles. In this study, SvelOBP1 was cloned based on the antennal transcriptome of S. velatus. The recombinant SvelOBP1 protein was expressed in Escherichia coli and purified by Ni-NTA resin. The predicted protein SvelOBP1 belonged to a classic OBP subfamily. The expression patterns revealed that SvelOBP1 was mainly expressed in the antennae of both males and females, whereas the expression of SvelOBP1 in other body parts could be neglected. The fluorescence binding assay indicated that SvelOBP1 displayed very strong binding affinities to dibutyl benzene-1,2-dicarboxylate and (Z)-hex-3-en-1-ol (K_i = 6.66 ± 0.03 and 7.98 ± 0.06 μM). The molecular docking results showed that residues Trp114, Phe115 and Asp110 may be involved in binding to both dibutyl benzene-1,2-dicarboxylate and (Z)-hex-3-en-1-ol and may have a great impact on odorant recognition of S. velatus. Our results provide evidence that SvelOBP1 might participate in the olfactory molecular perception of S. velatus and would promote the development of pest attractants for S. velatus control.

In this study, the complete mitochondrial genome of Ancylis sativa was sequenced and assembled. The circular genome is 15,262 bp in length and comprises 37 genes: 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and two ribosomal RNA (rRNA) genes, along with one AT-rich region. The average nucleotide composition is A = 40.95%, T = 38.04%, C = 13.01%, and G = 8.00%, resulting in an A + T content of 78.99%. Phylogenetic analysis indicated that Ancylis sativa was closely related to Ancylis unculana in the subfamily Olethreutinae, which can enhance the evolutionary and phylogeographic study of Ancylis sativa.

Emerging or poorly studied pests may require control before detailed information is available on their biology or management. We used Stephanitis chinensis Drake (Hemiptera: Tingidae), a poorly studied tea pest that feeds mainly on abaxial leaf surfaces, to determine how insecticide mobility, application method, and spray volume affect control efficacy. Twelve insecticides assigned to literature-based plant-mobile or contact-dominant categories were tested in leaf-dip bioassays at recommended field-rate concentrations and in field trials comparing misting with conventional spraying at 450 and 900 L/ha. Water-sensitive paper measured abaxial deposition across three canopy levels. At 48 h, 11 insecticides caused 90.0–100.0% mortality, whereas rotenone caused 66.0%. Field efficacy was significantly affected by mobility, application method, and assessment day, but spray volume had no significant main effect. Misting significantly improved efficacy in 34 of 36 comparisons for contact-dominant insecticides and 11 of 36 for plant-mobile insecticides; increasing spray volume improved only 1 of 72 comparisons. Under misting, droplet density and coverage exceeded measurement limits throughout the canopy (>300 droplets/cm²); conventional spraying produced lower deposition that declined toward the lower canopy. Improving abaxial and within-canopy deposition was more effective than increasing spray volume. Misting improved efficacy more frequently for contact-dominant insecticides such as bifenthrin and pyrethrins, whereas plant mobility of thiamethoxam, imidacloprid, sulfoxaflor, cyantraniliprole, and matrine may partly compensate for inadequate deposition.