Drosophila suzukii is a globally invasive pest causing substantial losses in soft fruit production systems. While diel activity has been studied under laboratory conditions, long-term high-resolution field data remain scarce. Here, we present a multi-year automated monitoring dataset from four field sites in South-West Germany (2017-2019) using traps sampling at 3-hour intervals, combined with high-resolution environmental data. Across the study period, D. suzukii exhibited strong seasonal dynamics, with low activity in winter and early spring, increasing in late spring and summer, and declining in autumn. Diel activity patterns were not constant but varied with seasonal abundance and environmental conditions. During periods of high activity, captures were concentrated in daylight hours and often showed bimodal peaks in the morning and late afternoon. In contrast, during low-abundance periods, diel patterns were weak or absent. Temperature effects on capture rates were season-dependent, showing positive associations in late spring and autumn but negative associations in summer. Rain consistently reduced capture rates across all seasons, whereas wind showed weaker and less consistent effects. Overall, our results show that diel activity of D. suzukii emerges under specific seasonal and environmental conditions rather than being a fixed behavioural trait. The custom-built automated trapping system proved reliable for high-frequency field monitoring and provides a scalable approach for other small insect monitoring systems. These findings emphasise the importance of considering both temporal resolution and environmental context when interpreting trap data and designing pest management strategies.

Foreign invasive species have caused considerable economic damage in fruiticulture during the past decade. Consequently, commercial fruit production is facing major, new challenges. Reasons for the spread of those pest insects are manifold. Appropriate control measures for the containment of invasive species depend on several years of experience with diverse fruit cultures and in-depth-knowledge of the insects & PRIME;behaviour. For Spotted Wing Drosophila, first efficient mechanisms for the control of fruit infestation were identified and are in use. Moreover, broad knowledge of biology, ecology, and genetics of this species is available and can be applied for the development of further control strategies. Research on invasive stink bugs is currently undertaken at different locations. Effective means for their population regulation are developed in those research projects.

Gebietsfremde invasive Schadinsekten haben im Obstbau im vergangenen Jahrzehnt große wirtschaftliche Schäden verursacht und den kommerziellen Obstanbau vor neue Herausforderungen gestellt. Die Gründe für die Ausbreitung dieser Insekten sind vielfältig. Regulierungsmaßnahmen zur Eindämmung dieser Neozoen benötigen Erfahrungen in verschiedenen Kulturpflanzen und umfangreiche Kenntnisse zum Verhalten der invasiven Arten. Für die Kirschessigfliege gibt es bereits erste wirksame Regulierungsstrategien, sowie eine Dekade an Erfahrung und somit umfangreiches Wissen zur Biologie, Ökologie und Genetik dieses Schadinsekts, welches für die Weiterentwicklung von Bekämpfungsmaßnahmen unabdingbar ist. Invasive Schadwanzen werden derzeit an verschiedenen Standorten intensiv untersucht. Potenziell wirksame, alternative Methoden zur Regulierung werden aktuell in Forschungsprojekten erarbeitet.

There has been an increase of invasive insect species during the last decade caused by a drastic change in the biotic communities as a result of an enormous increment of the international trade and the intercontinental transportation, as well as the influence by climate change on insect species. Drosophila suzukii Matsumura (Diptera: Drosophilidae) is emerging as a global threat because of its recent range expansion and the economic impact of crop fruit-colonizing populations. The aim of this work was to evaluate the toxicity effect of two essential oils obtained from plants native to Cuba on the invasive spotted wing drosophila. The susceptibility of males and females of D. suzukii to volatile compounds of Thymus vulgaris and Piper auritum at different concentrations was evaluated after 1, 4, and 24 hours of application. Half-maximal effective concentration (EC50) values at 24 h were calculated in each case. Both T. vulgaris (KD107) and P. auritum (KD48) oils made evident their high toxicity to D. suzukii males and females. The essential oil of T. vulgaris (107) at its highest concentration showed the highest percentage of total mortality. T. vulgaris essential oils could be considered as a source of bioactive substances compatible with integrated pest management (IPM) and biological control agents.

Spotted wing drosophila (SWD) causes significant economic loss in fruit crops to growers worldwide. There is immediate need for efficacious and selective monitoring tools that can detect infestations early. Previously, volatile organic compounds derived from apple were studied and a quinary chemical component blend (QB) was identified as the key SWD attractant in a blueberry orchard in the United States. This study’s aim was to determine whether previously observed QB efficacy, selectivity, and early detection levels could be attained within raspberry and cherry fields in the USA and Europe. Results demonstrated that sticky trap baited QB dispenser provided earlier SWD detection potential than the usually adopted apple cider vinegar (ACV) trap. The number of SWD captured/trap by QB baited trapping systems was significantly lower than that of the ACV trap. However, percent SWD/trap of QB baited traps was same within cherry. Lower non-target capture will save farmer/grower’s labor and time allocated to traps installation and drosophila species identification. Within the USA, SWD selectivity of QB baited liquid traps was consistently greater than sticky trap in raspberry field, suggesting that the QB dispenser can be an alternative to the standard ACV lure and that trap design could improve selectivity further.

The European cherry fruit fly, Rhagoletis cerasi (Diptera: Tephritidae), is a univoltine species that undergoes obligatory summer-winter diapause at pupal stage in the soil (2-5 cm) beneath host trees. To study the effects of photoperiod and relative humidity on diapause termination and post-winter developmental duration of R. cerasi, pupae collected from Dossenheim (Germany) were exposed to different photoperiod or relative humidity regimes during a chilling period ranging from 2 to 8.5 months. Specifically, pupae were exposed to four photoperiod regimes: (a) light conditions (24L:00D), (b) dark conditions (00L:24D), (c) short photoperiod (08L:16D) and (d) long photoperiod (16L:08D), as well as to three relative humidity regimes: (a) low (40% RH), (b) medium (60% RH) and (c) high (70-80% RH). Data revealed that relative humidity is not a significant predictor of diapause termination, but it affects the post-winter developmental period. Higher relative humidity promotes post-winter pupae development. On the other hand, photoperiod significantly affected both diapause termination and post-winter development of R. cerasi pupae. Light conditions (24L:00D) accelerate adult emergence, particularly for females. Regardless of the photoperiod (24L:00D, 00L:24D, 08L:16D), rates of adult emergence were high (>75%) for chilling intervals longer than 6.5 months. Nonetheless, exposure to a long day photoperiod (16L:08D), during chilling, dramatically reduced the proportion of adult emergence following 6 months exposure to chilling. Our findings broaden the understanding of factors regulating diapause responses in European cherry fruit fly, local adaptation and synchronization of adult emergence with the ripening period of major hosts.

Evidence is accumulating that evolutionary changes are not only common during biological invasions but may also contribute directly to invasion success. The genomic basis of such changes is still largely unexplored. Yet, understanding the genomic response to invasion may help to predict the conditions under which invasiveness can be enhanced or suppressed. Here we characterized the genome response of the spotted wing drosophila Drosophila suzukii during the worldwide invasion of this pest insect species, by conducting a genome-wide association study to identify genes involved in adaptive processes during invasion. Genomic data from 22 population samples were analyzed to detect genetic variants associated with the status (invasive versus native) of the sampled populations based on a newly developed statistic, we called C 2, that contrasts allele frequencies corrected for population structure. This new statistical framework has been implemented in an upgraded version of the program BayPass. We identified a relatively small set of single nucleotide polymorphisms (SNPs) that show a highly significant association with the invasive status of populations. In particular, two genes RhoGEF64C and cpo , the latter contributing to natural variation in several life-history traits (including diapause) in Drosophila melanogaster , contained SNPs significantly associated with the invasive status in the two separate main invasion routes of D. suzukii . Our methodological approaches can be applied to any other invasive species, and more generally to any evolutionary model for species characterized by non-equilibrium demographic conditions for which binary covariables of interest can be defined at the population level.

Drosophila suzukii (Diptera: Drosophilidae), is native to southeastern Asia and invaded Europe during the past decade. It causes serious economic damage in cherries and soft fruits. Control strategies rely on few insecticides with varying success. Due to environmental concern, the use of synthetic chemicals is restricted. Therefore, research effort is put into the quest for alternative substances applicable in chemical pest control. In laboratory assays, we tested 17 volatile plant compounds from different chemical classes for their contact toxicity, feeding modification, and oviposition repellency. Toxicity through contact with treated surfaces was evaluated after 1 h, 4 h, and 24 h; effects on food uptake were observed with capillary feeding (CAFE)—tests and oviposition trials compared egg numbers laid in raspberry medium with or without treated filter paper. Cinnamon oil and its components had the highest contact toxicity with an LC90 = 2–3%, whereas lemongrass oil, its main components, and farnesol were less toxic (LC90 = 7–9%), and geraniol was the least toxic. In CAFE tests, feeding stimulation was observed through 0.1% and 1% solutions of citronellol, lemongrass oil and farnesol. Cinnamon oil, cinnamaldhyde, and ethyl cinnamate were not consumed at a concentration of 1%. In the presence of citral, eugenol, and lemongrass oil, oviposition was reduced, and in the presence of limonene, no eggs were deposited. The natural products found most efficient in either bioassay will be further tested under field conditions.

ZusammenfassungDie Kirschessigfliege (Drosophila suzukii), heimisch in Südostasien, ist ein invasiver Schädling. Sie gehört zu der Familie der Taufliegen (Drosophilidae). Wohl durch den globalen Handel in die USA und nach Europa verschleppt, konnte sie sich seit 2008 in kürzester Zeit enorm ausbreiten. Geeignete Klimabedingungen, die Verfügbarkeit einer Vielzahl von Wirtspflanzen und das Nutzen einer ökologischen Nische, nämlich der Befall intakter reifender und reifer weichschaliger Früchte, waren hierfür ideale Voraussetzungen. Der Schädling verfügt zudem über ein großes Vermehrungspotential bei kurzer Entwicklungszeit sowie ausgeprägte Überwinterungsstrategien. Die Kirschessigfliege ist schwer zu bekämpfen und verursacht enorme Schäden.

The spotted wing drosophila (SWD), Drosophila suzukii, was first reported for Germany in 2011. Since then it has spread throughout central and southern Europe. This extremely polyphagous fruitfly causes economically important damage in soft berries and stone fruits. Moreover, it uses a broad range of wild hosts. Little is known about toxic effects of volatile and non-volatiles plant compounds on adult D. suzukii. Synthetic plant secondary compounds from different substance classes were tested for contact toxicity and potential effects as feeding attractants or repellents. Sixteen substances from flavonoids, phenolic compounds and terpenoids were used. Toxic effect through contact with treated surfaces was evaluated after 1 h, 4h, and 24 h. Repellent or attractant effects on feeding behaviour were tested with capillary feeding essays. Amounts consumed were measured after 4 h. Several effective substances could be identified. Possibilities for their use in IPM programs are discussed.

Over the last decade, Drosophila suzukii Matsumura, an invasive pest of soft-skinned fruits, gradually established itself in Europe, often resulting in significant economic losses. In 2011, when D. suzukii was first described for Germany, the Julius Kühn Institut (JKI) started a monitoring program in southwest Germany to study the occurrence and activity of the fly. Capture data from late 2011–early 2018 from 100 traps were analyzed for the effect of weather and immediate habitat on trap captures at different times of the year. We identified five phases in the annual population development cycle of D. suzukii. We found that the mild winter of 2013/2014 helped the thorough establishment of D. suzukii in Germany. Habitat types in the immediate vicinity of the trap and local weather conditions had a strong influence on trap captures. Forest borders and hedges were found to provide adequate overwintering shelter for the flies. Trap captures in forests and hedges were generally higher than those of vineyards and orchards, even during the fruiting seasons. Summer capture rates were correlated with the number of heat days and precipitation. We also discuss briefly the limitations of using trap captures as representative of fly density in the field.