The brown marmorated stink bug Halyomorpha halys (Stål, 1855), native to East Asia, is an extremely polyphagous pest that infests more than 300 plant species from 49 families. In Europe and North America, this pest causes enormous damage to the production of economically important crops (tree fruit, vegetables, field crops, and ornamental plants). Global warming favours its spread, as the rise in temperature results in the appearance of further generations of the pest. Halyomorpha halys (nymph and adult) causes damage typical of the Pentatomidae family by attacking host plants throughout their development (buds, stems, fruits, and pods). Ripe fruits are often disfigured, and later suberification and necrotic spots form on the fruit surface, making them accessible to plant pathogens that cause fruit rot and rendering them unmarketable. The increasing global importance of the pest suggests that more coordinated measures are needed to contain its spread. Understanding the biology and ecology of this species is crucial for the development of reliable monitoring and management strategies. Most insecticides available for the control of H. halys have a broad spectrum of modes of action and are not compatible with most integrated pest management systems, so biological control by natural enemies has recently been emphasised. Preventing excessive population growth requires early identification and effective control measures that can be developed quickly and applied rapidly while respecting the environment. This paper presents a comprehensive review of the latest findings on the global distribution of this important pest, its potential spread, biology and ecology, key host plants of economic importance, monitoring methods, and effective biological control strategies, as well as future perspectives for sustainable H. halys control measures.

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive pest that increasingly threatens apple production in Europe by causing fruit damage, yield losses, and quality deterioration under commercial orchard conditions. This study investigated seasonal population dynamics, spatial patterns of fruit damage, yield effects, and post-harvest fruit responses of two apple cultivars (‘Cripps Pink’ and ‘Fuji’) in a commercial orchard over two consecutive seasons (2024–2025). Adult and nymphal activity was monitored using pheromone traps, while fruit damage was assessed at harvest across orchard positions and canopy layers. Potential yield losses were estimated based on damage incidence, and selected physicochemical properties of healthy and affected fruits were analysed. Clear cultivar-dependent differences were observed. ‘Fuji’ exhibited typical external feeding damage, with low but consistent damage levels and limited yield losses in both seasons. In contrast, ‘Cripps Pink’ showed substantially higher damage rates and potential yield losses, particularly in 2025; however, classical external feeding damage was not observed. Instead, fruits exposed to H. halys pressure expressed atypical responses, primarily as increased individual fruit mass and size, and atypical skin color patterns, including pronounced striping and uneven pigmentation. Damage in ‘Cripps Pink’ was strongly structured within the orchard, with higher incidence in the upper and middle canopy layers and in areas adjacent to the forest edge, whereas damage in ‘Fuji’ remained low and spatially uniform. Overall, the results demonstrate that the impact of H. halys depends not only on pest pressure but also on cultivar traits and within-orchard spatial heterogeneity. These findings support the development of cultivar-specific and spatially targeted integrated pest management (IPM) strategies that better reflect the uneven distribution and expression of stink bug injury in commercial apple orchards.

The brown marmorated stink bug (Halyomorpha halys Stål, 1855) is a globally invasive polyphagous pest that challenges conventional chemical control. We evaluated caffeine-based preparations—alone and combined with chitosan, acetic acid, and ethanol—against adults under laboratory conditions using topical application and 72 h mortality readouts. Among caffeine-in-water treatments, 3% (w/v) yielded the highest mortality (52.5%), indicating an efficacy peak constrained by solubility/precipitation. The most effective overall formulation was 1% caffeine + 1% chitosan + 3% acetic acid, reaching 57.5% mortality and outperforming higher caffeine loads (3–5%). Ethanol as a co-solvent consistently reduced efficacy across concentrations. Patterns across treatments indicate that bioefficacy was driven predominantly by formulation chemistry rather than dose: the chitosan–acetic acid matrix enhanced cuticular deposition, retention, and diffusion of caffeine, whereas high caffeine levels likely triggered detoxification responses and/or reduced bioaccessible dose due to precipitation. By enabling lower active ingredient loads with equal or greater bioactivity, the biodegradable chitosan–acid system improves the environmental profile of caffeine-based insecticides. These results identify a practical, low-complexity path to optimize caffeine delivery for H. halys control and support integration into IPM frameworks. Field validation, testing on earlier life stages, and assessment of non-target effects and resistance biomarkers are warranted to translate these findings into robust, sustainable pest management strategies.

Halyomorpha halys is a highly polyphagous invasive pest whose management still relies heavily on broad-spectrum insecticides, creating a need for more sustainable behaviour-based alternatives. This study evaluated clove leaf and lemongrass essential oils (EOs) as potential repellents against adult H. halys by integrating behavioural bioassays, controlled-release formulations, molecular modelling and in silico ecotoxicological assessment. Male and female adults were tested in a two-choice Y-tube olfactometer; the individual EOs were encapsulated in calcium-alginate microspheres, and selected constituents were assessed using molecular docking and computational ecotoxicity models. Clove EO, lemongrass EO and their binary combination induced strong avoidance responses in both sexes, with pooled avoidance ranging from 90.0% to 96.7% and repellency indices from 0.80 to 0.93. No significant differences were detected among the three EO treatments when responses were pooled across sexes (χ² = 2.14, p = 0.343). Both EOs were successfully incorporated into calcium-alginate microspheres, with encapsulation efficiencies exceeding 90% (91.57 ± 0.67% for clove EO and 96.42 ± 0.29% for lemongrass EO). Lemongrass EO showed higher encapsulation efficiency and loading capacity and reached near-complete cumulative release, whereas clove EO release plateaued at approximately 70%. Phylogenetic, structural and physicochemical analyses supported the selection of H. halys HhOBP21 for comparative molecular modelling with the structurally characterised Drosophila melanogaster DmOBP28a. Molecular docking indicated that selected EO constituents could be accommodated within the binding cavities of these OBPs, with β-caryophyllene, α-humulene and limonene among the most favourably scored ligands, suggesting potential interactions with these proteins. Predicted acute toxicity values for the standard non-target test organism Tetrahymena pyriformis, Daphnia magna and Pimephales promelas remained below the applied thresholds for all evaluated compounds, although several constituents showed elevated predicted bioconcentration potential and limited biodegradability. Overall, the results demonstrate strong avoidance responses to the tested EOs under laboratory Y-tube conditions and support their further evaluation in semi-field and field studies to determine whether these responses translate into spatial repellency under practical conditions. Experimental validation of predicted molecular interactions and environmental fate is also needed.

The seasonal development and overwintering success of Halyomorpha halys remain insufficiently resolved in temperate continental regions of southeastern Europe, where climatic conditions may permit more than one generation per year. We monitored seasonal development, thermal accumulation, overwintering survival, and pheromone-trap captures of H. halys during 2024 and 2025 in continental Croatia. Experimental populations were maintained under unheated semi-outdoor conditions and followed from overwintered adults through oviposition, all five nymphal instars, and adult emergence. Degree-days were calculated above a lower developmental threshold of 12.2 °C. Two complete egg-to-adult generations developed in both years. The observed phenological interval from the first egg masses to first adult emergence was 56 days in 2024 and 42 days in 2025 for G1, and 49 and 53 days, respectively, for G2. Thermal accumulation during immature development ranged from 468.5 to 562.7 DD_12.2. First-generation adults emerged in early July in both years, whereas second-generation adults appeared on 12 September 2024 and 23 September 2025. Developmental stages overlapped during summer and early autumn. Overwintering survival under the two anthropogenic refuge conditions was low, reaching 9.4% under heated and 7.8% under unheated indoor conditions. Pheromone-trap catches showed marked seasonal variation but were not correlated with temperature, relative humidity, or precipitation during corresponding trapping intervals. These results demonstrate the developmental potential for two generations under temperate continental conditions in Croatia and provide phenological benchmarks for stage-specific monitoring. Monitoring should begin with spring adult activity and be intensified during May–June and again from late July onwards as successive generations develop.