Halyomorpha Halys Research Articles

First Record of Native Egg Parasitoid, Anastatus bifasciatus, on Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae) Eggs in Türkiye

Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae), the brown marmorated stink bug (BMSB), is an alien invasive pest that originated from South Asia (China, Japan, Taiwan, Korea) Many studies have shown that the number of invasions by pests has increased significantly in the last 5 centuries and the reason for this situation is directly related to human activities. Halyomorpha halys is considered to be a dangerous pest insect species due to economic losses in agricultural areas of the countries where it is distributed. It has been observed that the pest can have 1–2 generations per year and each egg mass contains of an average of 28 eggs and, furthermore, causes significant losses in many crops such as bean, hazelnut and pear. This study was conducted between July and August in 6 different areas and a total of 18 egg masses that were thought parasitized were collected from grape vine, tree of heaven, kiwi and hazelnut trees ) BMSB infested fields and kept in tubes to determine if they had parasitoids. Emerged parasitoids were fed with the 10% honey water solution and bred in tubes. In this study, Anastatus bifasciatus (Geoffroy) (Hymenoptera: Eupelmidae) was recorded as the first parasitoid of Halyomorpha halys in Türkiye.

Purification of acetylcholinesterase from Halyomorpha halys (Stål) (Heteroptera: Pentatomidae) and management of control of the Pest through inhibition of the enzyme

Purification of acetylcholinesterase from Halyomorpha halys (Stål) (Heteroptera: Pentatomidae) and management of control of the Pest through inhibition of the enzyme

Diversity, domain duplication, birth‐and‐death and adaptive evolution of fatty acyl‐CoA reductase genes in Hemiptera

AbstractFatty acyl‐CoA reductases (FARs) play an important role in the synthesis of fatty alcohols in various organisms. Based on the important function of FAR genes, they can be used as a potential molecular target for controlling agricultural pests. Although the FAR genes have been studied in a number of insects, the gain, loss, and molecular evolution of FAR genes between different Hemipteran species still require comprehensive and systematic study. This study systematically identified and analysed 352 FAR genes from 12 Hemipteran species, including six typical true bug species, Cimex lectularius, Apolygus lucorum, Halyomorpha halys, Oncopeltus fasciatus, Rhodnius prolixus and Gerris buenoi. The number of FAR genes per species ranged from 17 to 43, and a phylogenetic analysis showed that the identified FAR genes of Hemiptera can be classified into 11 clades. The gain and loss of FAR genes have occurred in some Hemipteran species. These FAR genes conform to the birth‐and‐death model in the evolutionary process. Through selection pressure analysis, we determined that G. buenoi in clade 11 evolved under the pressure of positive selection, with the evolutionary sites of A at position 214 and T at position 451, thus clarifying the differences in amino acids among species and providing a better understanding of the molecular evolutionary mechanism of Hemipteran FAR. In addition, structural analysis of the FAR genes revealed duplication of the two conservative domains, the Rossmann‐fold domain and the sterile domain, of the FAR in four species, namely Bemisia tabaci, Diaphorina citri, R. prolixus and Trialeurodes vaporariorum. This study lays a foundation for further studies on the molecular functions of Hemiptera FAR, and provides a possible new target for the control of Hemiptera, especially the stink bugs.

Halyomorpha halys and its egg parasitoids Trissolcus japonicus and T. mitsukurii: the geographic dimension of the interaction

Halyomorpha halys(Stål) (Hemiptera, Pentatomidae) was accidentally introduced to North America and Europe, becoming a key pest of many important crops. In its native range, it is attacked by egg parasitoids, includingTrissolcus japonicus(Ashmead), considered to be the main species, andT. mitsukurii(Ashmead) (Hymenoptera, Scelionidae).Trissolcus japonicuswas detected in North America in 2014 and Europe in 2017, whileT. mitsukuriiwas detected in Australia in the early 20thcentury and in Europe in 2016. Both species now appear established in the new areas. The present study used the MaxEnt algorithm to clarify the geographic dimension of the potential interaction betweenH. halysand these two parasitoid species, and to indicate where the release of one or the other parasitoid species is more likely to be effective. We found that the suitability for the two parasitoids overlaps theH. halysnative range completely. In invaded areas,T. japonicusshowed higher potential habitat suitability at the global scale, compared toT. mitsukurii, and also higher potential suitability at lower latitudes at continental and national scales. These results can substantially improve the effectiveness of biological control againstH. halys, by targeting the releases of parasitoids to the areas where each species is most likely to succeed.

Fruit Phenology of Two Hazelnut Cultivars and Incidence of Damage by Halyomorpha halys in Treated and Untreated Hazel Groves

Over the past decade, Halyomorpha halys has become one of the main threats to hazelnut production. Its trophic activity makes kernels inedible due to strongly detrimental effects on the organoleptic quality. Its management in Italy is still tricky due to the lack of effective native biocontrol agents and authorized and effective insecticides. A field test was performed on San Giovanni (SG) and Tonda Romana (TR) cultivars (early and late ripening, respectively) to assess the intensity of cimiciato damage with different pest management approaches (no insecticide and integrated pest management, IPM). Moreover, phenological analysis of fruits and the monitoring of stink bug species by traps and plant beating were carried out. In the untreated plots, the SG cv showed a higher cimiciato incidence with respect to the late TR cv (40% SG–NI vs. 23% TR–NI). This was probably due to the different phenological phases in which stink bugs injured the fruits. In fact, stink bug bites provoke different kinds of injuries (blanks, shriveled, and cimiciato) according to the fruit’s development period. Indeed, in the period of highest insect occurrence in the field, the fruits of the early cv (SG) were in kernel expansion, a phenological phase in which bug injuries are more likely in cimiciato defects. Lastly, the IPM did not provide sufficient fruit protection (19% SG–IPM vs. 11% TR–IPM). The interaction between the phenological development of hazelnuts and the brown marmorated stink bug represents a critical aspect in understanding and implementing effective strategies for controlling this key pest on hazelnut trees.

BIOLOGICAL CONTROL AND ANTAGONISTIC ACTIVITY OF NATURAL ENEMIES AGAINST, PAPILIO DEMOLEUS AT SAHATI REGION OF SINDH - PAKISTAN

The swallowtail butterfly is the widespread vigorous destructive pest of new growing green leaves of Citrus limon, the different species of predators and parasitoids on major pests were observed field and laboratory conditions during, 2022. The overall population of LBF was recorded (26.23±5.12) on C. limon leaves and the natural enemies were also observed namely; Peucetia viridans consequent to Cheiracanthium punctorium, Halyomorpha halys, Agelenopsis sp., Delta pyriforme (0.13±0.36), Geocoris punctipes (0.14±0.37), Aculepeira ceropegia (0.10±0.31), Menochilus sexmaculatus (0.12±0.34), Coccinella septempunctata (0.17±0.40), Brumus sp., (0.12±0.34), and ectoparasitiods; Tamarixia radiata (0.28±0.52), Tetrastichus sp., (0.30±0.54). The overall parasitiods population of eggs (11.44±2.00), larvae (6.98±1.22), and pupae (4.27±0.80), hence; the egg parasitoids; Telenomus sp., (0.11±0.33), and Ooencyrtus papilions (0.10±0.32), the larvae parasitoids, Distatrix papilionis (0.13±0.36), Apanteles papilions (0.09±0.30), and pupae parasitoids, Pteromalus puparum (0.10±0.32) were reported and found with differences in population occurrences. Thus; it is further recommended to keep toxic insecticides free lemon orchards and enhance the activity of natural enemies to reduce the pest population under field conditions.

Analyzing On-Farm Spatiotemporal Distribution of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) Populations from a Precision Agriculture Perspective.

The brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), is native to Japan, China, Taiwan, and Korea. Its dispersion from Asia to the United States of America and Europe caused serious damage to fruit, vegetables, and high-value crops. In Greece, damages are reported in kiwi orchards in the regions of Pieria and Imathia, which are the main production areas of kiwifruit. Greek kiwifruit production is expected to increase twofold within the next years. The aim of this research is to study the terrain and canopy properties that may have an impact on the development of H. halys populations. Thus, five kiwi orchards in total were selected in the regions of Pieria and Imathia. Τen traps were installed from early June to late October within each selected kiwi orchard-two types of traps at every side of the orchards and the center. The installed traps were examined weekly and the number of the captured H. halys was recorded. During the same days, sentinel satellite images were analyzed to calculate the vegetation index, NDVI (Normalised Difference Vegetation Index), and NDWI (Normalised Difference Water Index). The results showed population variability within the kiwi orchards since the population of H. halys was higher in areas with high NDVI and NDWI values. Additionally, our research revealed that H. halys prefers to develop populations at higher altitudes at both regional and field scales. The results of this research can be used to reduce damages by H. halys in kiwi orchards using different rates of pesticides depending on the prediction of the population size. There are multiple benefits of the proposed practice, such as a reduction in the production cost of kiwifruits, an increase in farmers' profit, and environmental protection.

Releasing and tracking the distribution of adventive Trissolcus japonicus (Hymenoptera: Scelionidae) in Virginia.

Adventive populations of Trissolcus japonicus (Ashmead), an egg parasitoid of the invasive agricultural pest, brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), have been detected in the United States since 2014. Given its importance as an H. halys biocontrol agent, efforts to redistribute T. japonicus began within some US states. Our surveillance for T. japonicus in northwestern Virginia in 2016-2017 yielded annual detections only in 1 county. Thus, to promote its broader establishment, releases of H. halys egg masses parasitized by T. japonicus from Virginia occurred in 2018 (2 releases) and 2020 (1 release) at 9 sites throughout Virginia's tree fruit production regions. Monitoring of T. japonicus and H. halys, using yellow sticky cards deployed in H. halys host trees and pheromone-baited sticky traps, respectively, was conducted from 2018 to 2022. Annual captures of H. halys adults and nymphs appeared to reflect adequate populations to support T. japonicus establishment across most or all sites. Prerelease monitoring yielded a single T. japonicus at 1 site. By 2022, T. japonicus was detected at or near 7 of the remaining 8 release sites, with first detections varying between 1 and 2 yr from the releases in 2018 and 2020. Captures at most sites were very low, but establishment at several locations was indicated by detections in 2-4 seasons. In 2022, T. japonicus surveillance at 11 additional sites in northwestern Virginia yielded detections at all locations, including those at which it had not been detected in 2016-2017, providing evidence for its range expansion.

Diversity of True Bugs (Hemiptera: Heteroptera) on Common Ragweed (Ambrosia artemisiifolia) in Southern Slovakia

The common ragweed (Ambrosia artemisiifolia Linnaeus 1800) is an exceptionally invasive species. The information on true bugs occurring on ragweed plants is limited in the invasion region. The objective of this study was to determine the species composition of Heteroptera associated with A. artemisiifolia, to assess their vectoring potential based on a literature review, and to compare species similarity in the surveyed fields. Field surveys were conducted in 2020–2021 at 10 sites in southern Slovakia. Sweeping and visual observations were conducted in field margins, weedy agricultural fields, and mowed meadows infested with A. artemisiifolia. In the study, food specialization, the abundance of individual species, and their assignment to families were precisely determined. The Jaccard similarity index was used to evaluate similarities in species composition among the sites studied. A total of 2496 true bugs were recorded, representing 47 species of Heteroptera from 12 families. The most common phytophagous species were Nysius ericae ericae (Schilling, 1829) (Pentatomomorpha, Lygaeidae), Adelphocoris lineolatus (Goeze, 1778), Lygus rugulipennis (Poppius, 1911), Lygus pratensis (Linnaeus, 1758) (Cimicomorpha, Miridae), and a zoophagous species Nabis (Dolichonabis) limbatus (Dahlbom, 1851) (Cimicomorpha, Nabidae). The species similarities in pair-wise combined localities were low, with a dominance of highly migratory and polyphagous species able to traverse the field from the adjacent landscape. A. artemisiifolia is a known host for plant viruses and phytoplasmas, and several Heteroptera species are carriers of these plant pathogens. Halyomorpha halys was the only detected vector of phytoplasmas, and its abundance on A. artemisiifolia was extremely low.

Does the fundamental host range of Trissolcus japonicus match its realized host range in Europe?

Unintentional introduction of natural enemies has increased in recent years due to a massive rise in global trade and tourism. One such natural enemy is the Asian egg parasitoid Trissolcus japonicus, a promising agent for classical biological control of Halyomorpha halys. In Europe, adventive T. japonicus populations have been detected in Switzerland, Italy and Germany. Host specificity testing demonstrated that its fundamental host range is fairly broad; however, it is unclear whether spatial or temporal refuges reduce parasitism of non-target species in the field. To address this, the realized host range of T. japonicus was assessed over three years by exposing sentinel egg masses of H. halys and 18 non-target species and collecting naturally laid egg masses in Switzerland and Italy. In total, 15 of 18 non-target species were successfully parasitized by T. japonicus in the field, confirming its broad fundamental host range. However, most non-target species were less parasitized by T. japonicus than H. halys, profiting from either partial temporal or spatial refuges from parasitism. Species with an unusual life cycle and the same ecological niche as H. halys, such as Pentatoma rufipes, which was the most parasitized non-target species in both countries, potentially face an increased risk of parasitism. In contrast, beneficial non-target effects may occur for the invasive pest, Nezara viridula, which suffered high non-reproductive mortality induced by T. japonicus. In both cases, life table studies will be needed to determine the impact of non-target parasitism and the potential consequences at the population level.

First report of Colletotrichum fioriniae infections in brown marmorated stink bugs, Halyomorpha halys

An epizootic caused by fungal pathogens occurred among Halyomorpha halys, brown marmorated stink bugs, while they were overwintering, with infections also occurring after overwintering. We report that one of the two pathogens responsible was Colletotrichum fioriniae (Marcelino & Gouli) Pennycook; a species well known as a plant pathogen and endophyte and which has only previously been reported naturally infecting elongate hemlock scales, Fiorinia externa. To prove pathogenicity, H. halys adults challenged with conidia died from infections and the fungus subsequently produced conidia externally on cadavers.

First record of Telenomus turesis (Walker), native egg parasitoid of invasive brown mamorated stink bug [Halyomorpha halys Stal (Hemiptera: Pentatomidae)] in Turkey

Halyomorpha halys (Hemiptera: Pentatomidae) Doğu Asya (Çin, Japonya, Kore ve Tayvan) kökenli bir türdür ve doğal yaşam alanlarında önemli bir polifag zararlı olup, yayılış gösterdiği alanları kısa zaman içerisinde yüksek bir popülasyon meydana getirerek istila etmekte ve tarımsal üretim için önemli bir tehdit oluşturmaktadır. Türkiye’de özellikle Karadeniz sahil şeridi boyunca yayılış gösterdiği alanlar içerisinde başta fındık olmak üzere pek çok üründe önemli kalite ve verim kaybına sebep olabilir. Bu çalışma, Sakarya’da farklı habitatlarda H. halys'in yerli yumurta parazitoitlerini ve bu türlerin etkinliklerini belirlemeyi amaçlamaktadır. Bu amaçla, arazi şartlarında elde edilen bir günlük yaştaki 20 yumurta paketi (600 yumurta) 9 farklı lokasyonda farklı bitkilere asılmış ve 4 gün sonra toplanarak laboratuvara getirilmiştir. Toplanan yumurtaların genel parazitlenme oranı %7,5 olmasına rağmen, bu yumurtalardan başarılı bir şekilde yalnızca üç parazitoit çıkışı meydana gelmiştir. Morfolojik olarak teşhisleri yapılan bu parazitoitler, sitokrom c oksidaz alt birim I genine (CO1) dayalı moleküler teşhis ile doğrulanarak, Telenomus turesis (Walker) olduğu belirlenmiştir. H. halys’in yerli yumurta parazitoit türü, bu çalışma ile Türkiye’de ilk kez rapor edilmektedir. Bu kapsamda istilacı türün ülkemizde yayılış gösterdiği alanlarda doğal düşman faunasının araştırılması, mücadele için önemli aşamalardan birisi olup daha fazla araştırmaya ihtiyaç duyulmaktadır. Ek olarak, uzun vadeli sürdürülebilir yaklaşım olan klasik biyolojik mücadele kapsamında, ithalatı gerçekleştirilen Trissolcus japonicus (Ashmead)’un hızlı ve kontrollü bir şekilde kitlesel üretimine geçilmesi ve salımı yüksek derece önem arz etmektedir.

First record of Cylindromyia bicolor (Diptera: Tachinidae) as an adult parasitoid of Halyomorpha halys (Heteroptera: Pentatomidae) in the world

Among the invasive insect species, Halyomorpha halys (Stål) (Heteroptera: Pentatomidae), has been causing significant damages in many parts of the world, particularly in vegetables, field crops and tree fruits. In the scientific studies conducted in Türkiye and the world so far, egg parasitoids of H. halys have been found, but adult parasitoids have not been detected. Two specimens of Cylindromyia bicolor were reared from an adult of H. halys collected in northern Türkiye (Borçka, Artvin). Adults of H. halys is reported for the first time as a host of Cylindromyia bicolor (Olivier) (Diptera: Tachinidae) in Türkiye as well as the rest of the world.

Effects of Irradiation on Biology and Mating Behaviour of Wild Males of Brown Marmorated Stink Bug Using a 6 MV Medical Linear Accelerator

The brown marmorated stink bug, Halyomorpha halys, is a pentatomid bug of Eastern Asian origin that became an economically relevant pest in the Eurasian and American continents. Management of this species is limited to use of chemical insecticides: an inefficient method due to the strong adaptability of the target pest. The sterile insect technique (SIT) is potentially a valid tactic in the search for nontoxic alternatives. In this work, we investigated the suitability of mass-trapped overwintering males, collected during the aggregation phase before the winter diapause, for their release as competitive sterile males in an SIT programme. Differently from previous studies, irradiation was applied with a linear accelerator device that produced high-energy photons. Following a similar scientific protocol with newly emerged irradiated males, the effects of X-ray irradiation on physiological parameters (longevity, fecundity and fertility) were assessed. In addition, behavioural bioassays were carried out in no-choice conditions to evaluate if irradiation interferes with mating processes. The results are very encouraging; the effects of the irradiation at 32 Gy did not differ from the controls in the longevity or fecundity of the exposed overwintering adults. The hatching rate of the eggs laid by the fertile females that had mated with the irradiated males was less than 5%. The results of behavioural bioassays showed that the irradiation did not cause a significant impact on the quality of the sterile males. More research is warranted to evaluate the mating competitiveness of sterile males in semi-field and field conditions.

Confirmatory evaluation of eFUME for control of brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae).

The governments of Australia and New Zealand require a phytosanitary treatment to control adult brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), as overwintering aggregations have been intercepted in the importation pathway of various nonhorticultural consignments, including vehicles. The commercialized fumigant, eFUME, a 16.7% by mass dilution of ethyl formate in carbon dioxide, resulted in complete control of ca. 1,000 field-collected, naturally diapausing adult H. halys in each of 3 independent trials at 10 ± 0.5 °C (x¯±2s) when ethyl formate levels in enclosure headspace were maintained steady-state at ca. 14.5 mg/liter for 4 h to yield Ct exposures ranging from 57.9 to 63.1 mg/liter h. Consistent with previous findings where greenhouse reared H. halys were controlled using laboratory formulations of this ethyl formate-carbon dioxide mixture, these confirmatory methods and results further inform technical and operational features of commercial practice.

Monitoring of the Brown marmorated stink bug Halyomorpha halys (Stål, 1855) in Banja Luka, Bosnia and Herzegovina

Brown marmorated stink bug Halyomorpha halys (Stål, 1855) is an invasive and polyphagous stink bug native to Asia. It has recently invaded Europe and Bosnia and Herzegovina. It is highly polyphagous pest of many economically important commodities including tree fruit, nut crops, field crops, vegetables and ornamentals. Moreover, it is an important nuisance pest because large numbers of adults seek out artificial structures for overwintering. Monitoring of population dynamics of H. halys during two years (2020 and 2021) was performed in Banja Luka, Bosnia and Herzegovina. The pest was present through monitoring period April–October with the highest abundance in the third decade of July when all life stages were present. More individuals were caught on pyramid trap (845) compared to sticky trap (156) favoring pyramid trap for future monitoring. Total number of caught individuals was 6.5 folds higher in the second year of the monitoring indicating population increase that presents threat to agricultural production.

Entomopathogens infecting brown marmorated stink bugs before, during, and after overwintering.

The microsporidian, Nosema maddoxi Becnel, Solter, Hajek, Huang, Sanscrainte & Estep, infects brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), populations in North America and Asia and causes decreased fitness in infected insects. This host overwinters as adults, often in aggregations in sheltered locations, and variable levels of mortality occur over the winter. We investigated pathogen prevalence in H. halys adults before, during, and after overwintering. Population level studies resulted in detection of N. maddoxi in H. halys in 6 new US states, but no difference in levels of infection by N. maddoxi in autumn versus the following spring. Halyomorpha halys that self-aggregated for overwintering in shelters deployed in the field were maintained under simulated winter conditions (4°C) for 5 months during the 2021-2022 winter and early spring, resulting in 34.6 ± 4.8% mortality. Over the 2020-2021 and 2021-2022 winters, 13.4 ± 3.5% of surviving H. halys in shelters were infected with N. maddoxi, while N. maddoxi infections were found in 33.4 ± 10.8% of moribund and dead H. halys that accumulated in shelters. A second pathogen, Colletotrichum fioriniae Marcelino & Gouli, not previously reported from H. halys, was found among 46.7 ± 7.8% of the H. halys that died while overwintering, but levels of infection decreased after overwintering. These 2 pathogens occurred as co-infections in 11.1 ± 5.9% of the fungal-infected insects that died while overwintering. Increasing levels of N. maddoxi infection caused epizootics among H. halys reared in greenhouse cages after overwintering.

Insecticidal activity of selected essential oils

Abstract The present work aimed to determine the insecticidal effects of three selected essential oils (EOs) of Pogostemon cablin, Thymus vulgaris, and Citrus aurantifolia against three insect species Melolontha melolontha, Halyomorpha halys, and Pyrrhocoris apterus. EO P. cablin showed very strong insecticidal effects against M. melolontha when it inhibited the insect species by more than 50% at concentrations of 50–6.25%. Against H. halys it also showed strong insecticidal effects at concentrations of 50–12.5%. The insecticidal activity against P. apterus was significantly lower than against the other insect species tested. The insecticidal activity of at least 50% was only observed at a concentration of 50%. EO T. vulgaris showed very strong insecticidal activity against M. melolontha which reached at least 50% at concentrations of 50–6.25%. When tested for its effect against H. halys, high efficacy was observed at concentrations of 50–12.5%. Against P. apterus, the efficacy was the lowest as 50% insecticidal activity was observed only at concentrations of 50% and 25%. EO C. aurantifolia showed only weak insecticidal activity against M. melolontha where the highest concentration tested killed 50% of the individuals. The very weak insecticidal activity was observed against H. halys where none of the tested concentrations had efficacy higher than 50%. The most pronounced effect of EO C. aurantifolia was observed against P. apterus where concentrations of 50% and 25% killed more than 50% of individuals. All tested EOs showed insecticidal effects and could potentially represent a natural alternative to synthetic insecticides.

The Invasive Caucasian Populations of the Brown Marmorated Stink Bug Halyomorpha halys (Hemiptera: Heteroptera: Pentatomidae) Rapidly Adapt Their Ecophysiological Traits to the Local Environmental Conditions

The ability to rapidly adapt to new environmental conditions is a crucial prerequisite for the wide-scale invasion of pests or intentional introduction of beneficial insects. A photoperiodically induced facultative winter diapause is an important adaptation ensuring synchronization of insect development and reproduction with the local seasonal dynamics of environmental factors. We conducted a laboratory study aimed to compare photoperiodic responses of two invasive Caucasian populations of the brown marmorated stink bug Halyomorpha halys (Hemiptera: Heteroptera: Pentatomidae), which recently invaded neighboring regions with subtropical (Sukhum, Abkhazia) and temperate (Abinsk, Russia) climates. Under the temperature of 25 °C and the near-critical photoperiods of L:D = 15:9 h and 15.5:8.5 h, the population from Abinsk showed a slower pre-adult development and a stronger tendency to enter winter adult (reproductive) diapause compared to the population from Sukhum. This finding agreed with the difference between the local dynamics of the autumnal temperature decrease. Similar adaptive interpopulation differences in the patterns of diapause-inducing responses are known in other insect species but our finding is distinguished by a very short adaptation time: H. halys was first recorded in Sukhum in 2015 and in Abinsk in 2018. Thus, the differences between the compared populations might have evolved over a relatively short span of several years.

Effect of landscape composition on the invasive pest Halyomorpha halys in fruit orchards

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), native to eastern Asia, has become one of the most serious pests of fruit orchards worldwide. This invasive species is highly polyphagous and capable of moving across the agricultural matrix at long distances. However, comprehensive studies exploring how landscape characteristics influence H. halys colonization of orchards are still lacking. Here, we investigated the impact of landscape composition on the trap captures of H. halys in 113 orchards of different fruit tree crops (i.e., apple, pear, peach, walnut and kiwi) in northern Italy. We found that landscapes rich in semi-natural habitats and vineyards and poor in annual crops supported a higher abundance of H. halys juveniles in traps. This pattern became more evident towards the end of the growing season as the abundance of juveniles increased. Adults were instead not affected by the landscape. The invasive stink bug best responded to landscape processes at large spatial scales (3000 m) confirming its high dispersal ability. Moreover, H. halys did not display a strong preference among fruit orchards, although fewer individuals were caught in walnut orchards. Our findings suggest that the habitat composition of agricultural landscapes is a key factor driving the dynamics of this pest in agroecosystems and that semi-natural habitats might be important in supporting H. halys populations and crop colonization. These effects are however limited to juveniles while adult density was similar even in landscapes with very contrasting structures.