Orange spiny whitefly (Aleurocanthus spiniferus Quaintance) is a major pest with economic significance to tea plants, as both nymphs and adults suck plant sap and contribute to the development of tea sooty mold. The occurrence of this pest varies considerably among different tea cultivars, even within the same plantation. This study aims to characterize the bioactive constituents of tea volatiles mediating A. spiniferus host selection, and leverage these semiochemicals to develop effective field trapping systems. Through field investigations and Y-tube olfactometer tests, we identified two highly preferred tea cultivars (‘Huangjinya’ and ‘Fuding white tea’) and two cultivars (‘Baiye No. 1’ and ‘Longjing 43’) that were not preferred. Behavioral assays and gas chromatography-mass spectrometry (GC-MS) analysis revealed four attractive compounds [hexanol, (E)-2-hexenal, linalool, and (E,E)-α-farnesene] and two repellent compounds [nonanal and (Z)-3-hexenol] in the volatile emissions of the four cultivars. A hexane solution (10 µL) of nonanol, (Z)-3-hexenol, linalool, and (E,E)-α-farnesene at a concentration of 100 µg/µL was able to elicit an obvious electrophysiological (EAG) response. In field trials, the synergistic bait trap equipped with two types of attractants, 500 µL of hexane solution of the mixture of linalool and (E,E)-α-farnesene (3:1, v/v), and the mixture of linalool and (Z)-3-hexenol (3:1, v/v) at the concentration of 100 μg/μL, showed significantly higher attractant efficacy and selectivity. Overall, this study indicates that tea volatiles play a crucial role in the host selection of A. spiniferus, and the synthetic mixtures of tea volatiles have the potential to be developed as commercial plant-based attractants for adult A. spiniferus. This study contributes to the development of sustainable, environmentally friendly management strategies for a pest that is challenging to prevent and control.

Aleurocanthus spiniferus, an invasive pest native to Southeast Asia, exhibits rapid dispersal capacity and high eradication resistance. In recent years, there have been continuous records of its invasion into new host plants. Odorant-binding proteins (OBPs) are essential at the peripheral level of olfaction, and their olfactory function has been partially confirmed by research. This study explores the functions of key OBPs mediating host selection by measuring the in vivo and in vitro binding capabilities of OBPs from A. spiniferus to host volatiles. Under exposure to more than five host volatiles, the two OBPs, AspiOBP1 and AspiOBP2, exhibited significant differential transcriptional regulation. AspiOBP1 exhibited good binding affinity to (Z)-3-hexenol and 3-carene, and with binding energies greater than −3 kcal/mol, ARG-79 might be the critical amino acid site for AspiOBP1 binding to host volatiles. AspiOBP2 exhibited no binding to any of the six tested volatiles in fluorescent competitive binding assays. Adults fed with dsAspiOBP1 showed significantly reduced behavioral and EAG responses to the attractant 3-carene and two repellents [(Z)-3-hexenol and nonanal]. Adults fed with dsAspiOBP2 lost both behavioral and EAG responses to the attractant 3-carene and the repellent (Z)-3-hexenol. The findings of this study not only elucidate the binding mechanisms between OBPs of A. spiniferus and host volatiles but also provide new targets for the future development of novel plant-derived insecticides and RNA-based pesticides to control this pest.

Aleurocanthus spiniferus not only damages plant leaves directly but also causes a sooty blotch due to the honeydew secreted by the nymphs and adults. This pest is widespread and seems to be spreading from low latitude to higher latitude areas where winters are typically colder, indicating an increase in its cold tolerance. Changes in temperature help insects to anticipate the arrival of winter, allowing them to take defensive measures in advance. This study examines the impacts of brief warm pulses on the low-temperature tolerance of A. spiniferus, and analyzes the physiological and biochemical mechanisms underlying its cold adaptation, utilizing seasonal differences in cold tolerance. Intermittent training at 25 °C significantly improved the survival rate of overwintering nymphs (third and fourth instar) at −7 °C. Analysis of seasonal differences in the supercooling point (SCP) and freezing point (FP) revealed that overwintering nymph had the highest cold tolerance in November. Seasonal variation in levels of cold-resistant substances were also observed, with moisture decreasing during overwintering, while fat and glycerol levels increased. Conversely, glucose, sorbitol, and trehalose levels rose significantly at the end of the overwintering period. The expression profile of cold-resistant genes indicated that the aldo-keto reductase family 1 member B1 in Aleurocanthus spiniferus (AspiAKR1B1) shows a significant decrease at the end of the overwintering period. Knocking down AspiAKR1B1 led to a marked reduction in the cold tolerance of A. spiniferus. Therefore, brief warm pulses and AspiAKR1B1 are key factors contributing to the enhanced cold tolerance of A. spiniferus. This research provides theoretical support for preventing the further spread of A. spiniferus to higher latitudes, and offers technical guidance for developing effective pest control measures.

Apolygus lucorum is one of the main pests affecting tea quality. Chemical control is the primary method for managing this pest, but issues such as pesticide residues and the development of resistance are inevitable. The pest’s extensive host range holds significant practical implications for developing novel food baits. This study first investigated the preference of adult A. lucorum for tea branches under different conditions and various host plants by using the Y-tube olfactometer. Subsequently, the trapping efficacy of active tea volatile components and food baits was tested. The results revealed that adult A. lucorum exhibited a stronger preference for healthy and mechanically damaged tea branches, while they avoided branches infested with high densities of conspecifics. Adult A. lucorum showed significantly higher selection rates for Gossypium hirsutum, Vigna radiata leaf, Glycine max leaf, Phaseolus vulgaris, Lablab purpureus, and Brassica pekinensis compared with healthy tea branches. In field trials, three tea volatile baits showed effective trapping performance, (E,E)-α-farnesene, nonanal, and (Z)-3-hexenol. Three mixture baits of foods and tea plant volatiles, B. pekinensis + (Z)-3-hexenol, P. vulgaris + (E,E)-α-farnesene, and S. melongena + (Z)-3-hexenol, not only demonstrated high attractiveness but also maintained a residual effect period as long as 20 days. This study provides new insights and approaches for the integrated management of A. lucorum and offers technical support for the development of novel green pest control technologies in tea plantations.

Empoasca onukii severely damages tea plants as a major sap-sucking pest, leading to the increasing adoption of biopesticides as a sustainable alternative to chemical control. However, existing research has largely focused on the final lethal effects of these agents, while their short-term interference patterns on pest feeding behavior remain unclear. In this study, six biopesticides—azadirachtin, matrine, Beauveria bassiana, Metarhizium anisopliae CQMa421, Mamestra brassicae nucleopolyhedrovirus (MbNPV), and Bacillus thuringiensis (Bt)—were evaluated using the electrical penetration graph (EPG) technique to precisely analyze their interference on the short-term (6 h) feeding behavior of E. onukii, alongside field trials to validate control efficacy. EPG analysis revealed that different types of biopesticides significantly disrupted feeding in distinct ways. The two botanical pesticides and CQMa421 mainly prolonged the non-probing phase (waveform Np) and reduced active non-phloem feeding (C waveform) (p < 0.05); Bt and B. bassiana significantly extended the resting phase (waveform R) and decreased the frequency of passive phloem feeding (waveform E) (p < 0.05), whereas MbNPV exhibited a combined effect, simultaneously prolonging both Np and R waveforms while reducing waveform C (p < 0.05). Field trials showed that all tested treatments achieved complete control (100%) at 21 days post-application. Moreover, across a wide range of concentrations, they all demonstrated excellent and stable control performance. These findings provide diverse agent options for the green control of E. onukii in tea plantations and lay a foundation for constructing a green integrated pest management system centered on biological control for tea plant pests.