While thermal acclimation refers to the acquisition of thermal tolerance following sublethal pre-exposure under laboratory conditions, acclimatization describes the same plastic process occurring in the field, in response to both thermal and non-thermal cues. This distinction has led to concerns that laboratory experiments may not fully portray the costs and benefits of field acclimatization, particularly regarding overwintering capacity. We studied adult and developmental lab acclimation in Drosophila suzukii, at both constant and fluctuating regimes, as well as field acclimatization at various times of the year. We assessed cold tolerance and metabolomic profiles using targeted and untargeted tools. All acclimatory treatments promoted cold tolerance. Developmental acclimation and acclimatization produced comparable cold tolerance, exceeding that of adult acclimation. In acclimatized flies, cold tolerance rose progressively from September to December. Metabolomic profiles revealed shared cryoprotective compound accumulation, but also treatment-specific differences across acclimation and acclimatization treatments. Although constant laboratory acclimation is often assumed to fail to capture the intricacies of environmental variability and the associated phenotypic changes, our findings show that even this simple approach can serve as a robust predictor of D. suzukii's thermal tolerance mediated by natural acclimatization, thereby validating a broad body of laboratory research conducted on Drosophila and other insects.

Bacillus toyonensis is a gram-positive bacterium within the Bacillus cereus group, primarily recognized for its probiotic properties. Recently, a strain designated B. toyonensis biovar Thuringiensis (Bto_UNVM-94) was reported to produce parasporal crystals with dual insecticidal activity against Cydia pomonella and Anthonomus grandis. In this study, we describe and characterize a previously undescribed strain, B. toyonensis biovar Thuringiensis Bto_UNVM-42, which exhibits nematicidal and nematostatic activity, representing the first report of these effects within this species. Whole-genome sequencing revealed the presence of a large plasmid containing multiple putative pesticidal genes, including five cry genes encoding Cry32-like proteins, two additional cry genes encoding Cry69-like and Cry73-like proteins, three cyt genes encoding Cyt1-like proteins, and two mpp genes encoding Mpp-like proteins. In addition, the genome encodes four chitinases and two proteins with significant similarity to the nematicidal Sep1 protease from Bacillus firmus. Proteomic analysis of parasporal crystals confirmed the expression of Cry32-family proteins. Bioassays showed that strain Bto_UNVM-42 was not toxic to Aedes aegypti, Alphitobius diaperinus, Anthonomus grandis, Cydia pomonella or Drosophila suzukii. In contrast, it exhibited nematicidal activity against Panagrellus redivivus, low but detectable mortality (8%) against Meloidogyne javanica, and a reversible nematostatic effect on Pratylenchus zeae. Taken together, the available bioassay observations and the genomic and proteomic data are consistent with a predominantly enzyme-driven rather than a classical crystal toxin-mediated mode of action. Overall, these findings expand the known biocidal spectrum of B. toyonensis and highlight its potential relevance for the development of biological strategies for nematode management.

A machine learning framework for predicting peptide inhibitors of insect voltage-gated sodium channels.

The spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), is a highly invasive fruit pest that has rapidly spread across Europe, the Americas, and parts of Africa since 2008. Its ability to oviposit in intact ripening fruits makes it particularly destructive, with infestations leading to severe economic losses in stone fruits, berries, and grapes. In Italy, the Ministry of the Ecological Transition (MiTE) authorized the release of the exotic larval parasitoid Ganaspis kimorum (Hymenoptera: Figitidae) in 2021 under a National Biological Control Plan. The initiative included releases in several regions and in the Autonomous Province of Bolzano/Bozen, where fruit orchards and surrounding habitats were selected as release sites based on confirmed D. suzukii infestations and minimal pesticide use. This study presents monitoring results from South Tyrol between 2021 and 2024, focusing on the establishment, spread, and overwintering of G. kimorum as well as the presence and abundance of other parasitoid species that emerged from the sampled fruits.

Multifaceted sublethal effects of neurotoxic insecticides on olfactory-mediated orientation in the spotted wing drosophila.

Drosophila suzukii is a devastating global pest of soft-skinned fruits, yet its population dynamics in mountainous agricultural systems where cultivation extends across elevational gradients remain poorly understood. To address this gap, we conducted 2 years of intensive monitoring (2023-2024) in sweet cherry (Prunus avium) orchards at three elevations (1360-1910 m) in Wenchuan, China, characterizing adult population fluctuations and fruit infestation patterns. Adult population peaks were progressively delayed with increasing elevation, closely tracking local cherry phenology. Generalized linear mixed models revealed that adult abundance was positively associated with mean temperature and fruit maturity, with temperature effects strengthening significantly at higher elevations. Despite the later population buildup, infestation incidence at the highest site (1910 m) reached the 40% infestation threshold at a fruit maturity ratio 0.459 lower than at the lowest site (1360 m), indicating heightened susceptibility of high-elevation orchards. Field surveys identified 11 non-crop host species supporting D. suzukii reproduction before sweet cherry maturation. Notably, early-ripening Lonicera standishii at high elevations and Prunus pseudocerasus at low elevations served as critical population reservoirs. Interplanting with P. pseudocerasus advanced both the seasonal arrival of D. suzukii and the onset of sweet cherry damage by 5-10 d. These findings demonstrate that elevational gradients create asynchronous pest pressure, with high-elevation orchards facing disproportionately rapid infestation despite cooler temperatures. We provide an empirical basis for elevation-specific monitoring and management strategies such as the sterile insect technique, emphasizing targeted early-season intervention in non-crop hosts to mitigate spillover into commercial plantings.

Herbivorous insects use volatile organic compounds (VOCs) to find food, mates, and oviposition sites. Understanding these cues is key for behavior-based pest management. Spotted-wing drosophila (Drosophila suzukii Matsumura) (Diptera: Drosophilidae) is an invasive pest that attacks ripening fruit. Although fruit VOCs attract this species, the role of nonfruit plant volatiles, such as those emitted by leaves, remains unclear. Here, laboratory and semifield behavioral assays were used to test whether leaf volatiles enhance adult D. suzukii attraction and oviposition on blueberry fruit, followed by gas chromatography-mass spectrometry characterization of fruit and leaf VOCs and behavioral and electroantennographic (EAG) assays to assess responses to individual compounds. In laboratory trials, both sexes were significantly more attracted to fruit when leaves were present compared to fruit alone. Likewise, oviposition rates increased in the presence of leaves during cage choice experiments. Leaves were more fragrant than fruit on a per gram basis, emitting both a greater quantity and number of compounds. Among the VOCs emitted in greater amounts from the “fruit + leaf” treatment than from “fruit” alone, 9 compounds were examined, and 2—linalool and 6,10,14-trimethyl-2-pentadecanone—attracted females individually and in a blend and elicited strong EAG responses. These findings demonstrate that attraction is influenced by a combination of plant-derived cues; however, further field studies are needed to confirm these results under natural conditions. This knowledge advances our understanding of D. suzukii chemical ecology and may support the development of improved monitoring tools and behavior-based control strategies for this pest.

The invasive, soft-skinned fruit dipteran pest Drosophila suzukii (Matsumura), commonly known as the spotted-wing drosophila (SWD), causes severe damage to the blueberry production system in several western countries. Current management relies on frequent insecticide applications timed with fruit ripening, which increases resistance risk and environmental concerns. In this study, we investigated 5-hydroxymethylfurfural (5-HMF), a sugar derivative volatile identified by gas chromatography-mass spectrometry (GC-MS) analysis from a novel D. suzukii attractant Decoy Attract and Kill (A&K) (Batch no. 24026021), that exhibited strong behavior-disrupting effects on D. suzukii. We then evaluated the D. suzukii behavioral disruption of 5-HMF with electroantennography (EAG), Drosophila Activity Monitor (DAM), and laboratory and field oviposition trials. Moreover, the toxicity of 5-HMF and its developmental delay were also assessed. Exposure to the 2 mM Decoy A&K and increasing concentrations of 5-HMF resulted in an increased residence time, suggesting prolonged attraction or orientation-change behavior. Flies exposed to ≥ 10 mM 5-HMF showed significantly lower egg counts in blueberries and exhibited increased mortality. Additionally, ≥ 5 mM of 5-HMF showed a clear dose-dependent developmental delay, from the egg to pupal and adult stages. These findings suggest that 5-HMF acts as both a behavioral and developmental disruptor for D. suzukii. Thus, 5-HMF can serve as a novel A&K candidate supporting integrated pest management (IPM) strategies for sustainable control of D. suzukii.

The spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), has become a global invasive pest of soft-skinned fruits over the past decade. Researchers have investigated various biological control agents and their potential applications for D. suzukii management. This special collection summarizes recent advances and highlights major achievements in the biological control of D. suzukii. These include early-stage releases of the introduced Asian larval parasitoid, Ganaspis kimorum Buffington (Hymenoptera: Figitidae), in the United States and Europe; the adventive establishment of another key Asian larval parasitoid, Leptopilina japonica Novković & Kimura (Hymenoptera: Figitidae), in North Amreica and Europe; methods for the cold storage of G. kimorum; effective sampling techniques for assessing the presence, relative abundance, and seasonal phenology of figitid parasitoids; the potential compatibility of other biological control agents (entomopathogens) with parasitoids; and assessment of specific insecticide impacts on common parasitoids. Finally, this special collection concludes with a proposed research, development, and implementation roadmap to improve biological control strategies for D. suzukii.

Phytosanitary irradiation (PI) has been advancing consistently in recent years, partly due to its broad applicability to fresh produce and insect pests. Internationally adopted PI treatment schedules cover all plant hosts associated with a target pest. Thus, it is crucial to evaluate the impact of commodity-related postharvest practices on PI efficacy. For instance, modified atmospheres (MA) used to extend the shelf life of fresh produce might increase insect radiotolerance. Hence, we tested the extent to which combining atmospheric (severe hypoxia-N2, severe hypoxia-CO2, hypoxia, and normoxia) and storage conditions (25 and 0 °C) affects PI efficacy against Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). Late pupae of D. suzukii were irradiated at nominal doses of 52 Gy (suboptimal dose) and 72 Gy (PI dose). Prevention of egg laying was considered the treatment endpoint. Our results showed that egg laying was prevented in PI-treated females at 72 Gy, regardless of atmospheric or storage conditions. Females irradiated with the suboptimal dose of 52 Gy under severe hypoxia laid significantly more eggs than in normoxia or hypoxia. Ovary dissections and scanning electron microscope (SEM) imaging confirmed irreversible damage in the reproductive tract of PI-treated D. suzukii females. We conclude that a minimum absorbed dose of 80 Gy is effective for D. suzukii, preventing egg laying even under modified atmosphere and cold storage conditions.

Gut microbial dysbiosis is associated with detoxification impairment in parasitoid wasps exposed to Emamectin benzoate.

Drosophila suzukii Matsumura poses a significant threat to various soft-skinned fruit crops, causing substantial economic losses worldwide. Behavioral management using the repellent 2-pentylfuran has shown potential to manage this invasive pest. This 2-year study aimed to improve the effectiveness of 2-pentylfuran and identify cost-efficient deployment tools. In 2022, we evaluated automated canister puffers in isolated raspberry plantings and in semi-field cage trials using choice and no-choice assays. In 2023, we tested polyvinyl chloride spiral dispensers combined with below canopy insecticide applications in a large-scale raspberry planting, assessing D. suzukii infestations 72 h after 2-pentylfuran deployment. In addition, we monitored natural enemy and pollinator activities in both years using yellow sticky cards and visual counts, respectively. Treatments using 2-pentylfuran delivered by either puffers or spirals resulted in a small reduction in D. suzukii infestation, particularly in fall-bearing raspberries. However, combining 2-pentylfuran with insecticide in 2023 did not significantly improve efficacy. In semi-field trials, puffer density significantly reduced infestation in choice assays, while puffing frequency had no significant effect in either choice or no-choice assays. Importantly, 2-pentylfuran did not adversely affect the activity of beneficial insects and increased parasitism by the larval parasitoid Leptopilina japonica Novković & Kimura, potentially complementing biological control. Our findings suggest that further optimization of deployment strategies may facilitate the commercial integration of 2-pentylfuran into D. suzukii management programs.

Sweet orange essential oil (Citrus sinensis) and its major component d-limonene were formulated as emulsions and low- and high-energy nanoemulsions and evaluated for toxicity against adults, larvae, and pupae of Drosophila suzukii, as well as for selectivity toward the pupal parasitoid Pachycrepoideus vindemmiae. High-energy nanoemulsions produced smaller and more homogeneous droplets (221–289 nm; PDI 0.210–0.255) compared with low-energy nanoemulsions (617–796 nm; PDI 0.548–0.644), indicating improved dispersion and potential stability. Toxicity assays revealed that the pure essential oil and d-limonene were the most toxic to adult D. suzukii (LC50 = 1.7 wt% and 0.54 wt%, respectively), followed by high-energy nanoemulsions, emulsions, and low-energy nanoemulsions. Although pure compounds showed slightly higher toxicity, high-energy nanoemulsions maintained comparable efficacy, suggesting improved delivery without major loss of activity. Larval mortality did not exceed 40% across treatments, whereas pupae were markedly more susceptible. High-energy nanoemulsions of both orange essential oil and d-limonene produced the highest pupal mortality (around 85%), followed by low-energy nanoemulsions (72–77.5%) and emulsions (50–75%). In addition, emulsified and nanoemulsified formulations induced developmental abnormalities in emerged adults, with malformation rates reaching 30%. Selectivity assays demonstrated low toxicity of all formulations to adult P. vindemmiae, with mortality generally below 20% and a negligible reduction of parasitism activity in most treatments. Overall, the formulation method strongly influenced physicochemical properties and insecticidal performance. High-energy nanoemulsions enhanced efficacy, particularly against pupae, while maintaining low toxicity to a key parasitoid. These findings indicate that nanoformulated citrus essential oils represent promising selective and environmentally compatible tools for integrated management of D. suzukii.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13205-026-04833-9.

Drosophila suzukii (Matsumura), spotted-wing drosophila is an extremely destructive, invasive global pest of small fruit production. Frequent insecticide applications are the most commonly used management tool against this pest, as females deposit eggs in ripening fruit leading to larval infestation at harvest. However, other strategies aimed at reducing D. suzukii infestation continue to be explored to reduce reliance on insecticides and increase ecological sustainability. One such strategy is deployment of attracticidal spheres; these are visually attractive red spheres that provide a continuous release of a fresh toxicant and feeding stimulant mixture on their surface. However, optimal deployment strategies for spheres within small fruit plantings have not been developed to maximize their impact against foraging D. suzukii adults. Here, we evaluated deployment height of spheres within the canopies of small fruit plants (blueberry, raspberry and blackberry) in conventional production systems in 3 states, and whole plot (grid) and perimeter sphere deployment layouts in both conventional and organic blueberry production systems in 6 states. In separate studies, we also evaluated the potential for nontarget impacts on biological control agents and pollinators. While we observed reduced infestation, based on sphere deployment in some trials, results were not consistent likely due to differences in production practices and D. suzukii relative densities. We also did not observe negative impacts on natural enemies or pollinators. Ultimately, for attracticidal spheres to be of value to small fruit growers, more information regarding management practices that enhance or limit their efficacy must be conducted.

The seasonal phenology of spotted wing drosophila ( Drosophila suzukii Matsumura) was examined in central Alabama during 2018, 2020, 2021, and 2023 using baited traps. Across these years, 50,899 adults were captured, with significantly higher numbers recorded in 2020 and 2021. Timing of first captures and population peaks varied considerably, occurring as early as 19 Mar (Julian day 79) in 2020 and as late as 19 Jul (Julian day 200) in 2018. Cumulative degree-day (DD) accumulation at first adult capture averaged 1550.3 DD (7.2 °C base temperature) and 1148.8 DD (10 °C base temperature), but with high variability among years. Mean daily temperature and dew point were relatively consistent across capture events and precipitation and relative humidity were more variable. Sixth-order polynomial models were significant each year ( R 2 = 0.614% to 0.791%), revealing multiple seasonal peaks. However, the pooled model explained less variation ( R 2 = 0.228), suggesting stronger year-specific than pooled trends. DD-based logistic and Weibull models successfully predicted cumulative captures, with 25%, 50%, and 75% occurrence at 1253, 1615, and 1975 DD, respectively. These results demonstrate that D. suzukii phenology in the southeastern United States is highly variable among years, shaped more by cumulative heat unit accumulation than by daily weather fluctuations. DD models provide a useful framework for forecasting seasonal activity and can support integrated pest management strategies in regional berry production systems.

The sterile insect technique (SIT) suppresses insect reproduction by repeatedly releasing sterile insects and allowing them to mate with insects of the same species in the wild. While the classical SIT relies on sterile males mating with wild females, there is a debate regarding the risks and benefits of releasing sterile females along with the sterile males (i.e. bisexual releases). In a replicated cage experiment, we compared the effect of unisexual and bisexual sterile releases of Drosophila suzukii on induced sterility. To ensure field-realism, fertile females - wild-F0 freshly emerged from field-collected sweet-cherries - were placed in cages with artificial vegetation and plastic berries. The proportion of fertile females that produced offspring was not significantly different in unisexual and bisexual treatment (45% and 46%, respectively). Excluding females that had not mated (i.e. no sperm in the spermathecae) from the analysis had no influence. These results suggest the release of sterile females does not always affect the efficacy of the SIT. Even though additional phenomena may arise when scaling up from cages to the field, we conclude that sorting females with genetic constructs or robotic systems is probably dispensable in D. suzukii SIT, at least when deployed in confined farming systems. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Thermal Death Time (TDT) model has enabled quantification of heat injury in ectothermic organisms across variable thermal stress intensities and durations. Using experimental data from Drosophila suzukii, here we extend this framework to include a quantitative assessment of repair of thermal injury. We first demonstrate that heat injury accumulates additively and exponentially at stressful temperatures and subsequently show how repair of heat injury also depends on both temperature and duration across permissive temperatures. We find repair to be additive across different permissive temperatures, with the highest repair rate at intermediate temperatures. Importantly, integration of injury and repair rates enables accurate predictions of thermal failure during simple temperature fluctuations alternating between stressful and permissive temperature ranges. Our data therefore support an extension of the TDT framework to integrate injury-repair dynamics. With further validation for other traits and taxa, these dynamics will be critical for assessing thermal vulnerability in a warming climate.

Entomopathogenic nematodes as biological control agents against Drosophila suzukii (Diptera: Drosophilidae)

ABSTRACT The parasitoid Leptopilina japonica Novković & Kimura (Hymenoptera: Figitidae) is a natural enemy of the invasive Drosophila suzukii Matsumura (Diptera: Drosophilidae), which is a significant pest in berry and fruit production. Both species originate from East Asia and after its initial detection in Europe in 2019, L. japonica has quickly spread and has established more northwards in several countries. Therefore, the potential of L. japonica for natural regulation of D. suzukii needs to be evaluated under various climatic conditions. This study is the first to examine the life history traits of L. japonica under fluctuating temperature and humidity conditions relevant in Central Europe, one of its new distribution areas and that from its main host D. suzukii . Average values for early (16.1°C–27.2°C) and late (12.3°C–23.9°C) summer days in Germany, during which host populations begin to increase or reach their peak, respectively, were simulated in the laboratory. Single pairs of wasps were mated and regularly provided with fresh hosts ( D. suzukii L2‐larvae) from emergence until death under the conditions of early and late summer in comparison to standard rearing conditions (permanent 23°C, 60% humidity). Parasitized hosts were further incubated under these conditions until emergence. The development rate did not differ between early summer and the control group, but was somewhat delayed under the cooler conditions of late summer. At this regime, however, the lifespan, lifetime fecundity, proportion of female offspring, and apparently also mating success were higher. These findings indicate the best performance of the parasitoid during the peak of its host's population density toward the end of the season and are also consistent with current observations that L. japonica is most common in late summer. In summary, analyses of thermal performance should account for fluctuating conditions in order to more reliably predict a parasitoid's field performance.

The use of alternative hosts is a key strategy for enhancing the efficacy of parasitoid wasps in pest control. Pachycrepoideus vindemmiae is an important pupal ectoparasitoid of numerous agricultural and public-health pests, including Drosophila suzukii, Bactrocera dorsalis, and Megaselia scalaris. However, a suitable alternative host for the mass rearing of P. vindemmiae has yet to be established. In this study, we compared the biocontrol traits of P. vindemmiae reared on Drosophila melanogaster (PVm) with those reared on the larger alternative host Drosophila virilis (PVv). PVv exhibited a developmental duration similar to that of PVm but attained a significantly larger body size. PVv also showed higher survival under temperature stress (4 °C and 35 °C) and during starvation. Furthermore, PVv achieved significantly higher parasitism rates against Drosophila suzukii, B. dorsalis, and M. scalaris, likely attributable to its greater number of mature eggs and enhanced reproductive capacity. Transcriptomic analysis revealed up-regulation of genes associated with stress resistance, growth and development, and venom function, which may collectively contribute to the improved biocontrol performance of PVv. In summary, rearing P. vindemmiae on D. virilis enhances its biocontrol potential, offering a promising strategy to mitigate public-health risks and reduce agricultural economic losses. © 2026 Society of Chemical Industry.