Nezara Viridula Research Articles

Inventory of Pests on Local Potato Plants from Soe in South Central East District, Province of East Nusa Tenggara

Sub-districts Kie and Fatumnasi are two sub-districts in mainland West Timor that cultivate local potatoes from Soe. This germplasm needs to be preserved and developed to diversify non-rice alternative food. One of the main obstacles in cultivating potatoes is the presence of pests, but so far there have been no reports of pests on local potato plants from Soe from the two sub-districts, so this research needs to be done. This study aimed at an inventory of important pests on local potato plants from Soe as a database for early detection to prevent the occurrence of explosive pests. This research was conducted on potato plantations in Fatuulan Village, Ayofanu Village, Nunleu Village, and Nenas Village. The method used is a purpose survey at a specified sample point. A sampling of insect pests is done by direct observation and insect nets. The pests found were put in a killing bottle or 70% alcohol, collected, and identified. Observation variables include the type of pest, symptoms of pest attack, and morphological characteristics of the stadia found. The data obtained were analyzed descriptively. The results showed that five species of pests damaged local potatoes from Soe. The five pests were Spodoptera litura, Henosepilachna vigintioctomaculata, Liriomyza sp, Phthorimaea operculella, and Nezara viridula. The identification results showed that in Kie District there were three pest species, namely S. litura, H. vigintioctomaculata, and Liriomyza sp. Meanwhile, in Fatumnasi District, there were four types of pests, namely H. vigintioctomaculata, Liriomyza sp, P. operculella, and N. viridula

Diversity and composition of the microbiome associated with eggs of the Southern green stinkbug, Nezara viridula (Hemiptera: Pentatomidae).

Although microbial communities of insects from larval to adult stage have been increasingly investigated in recent years, little is still known about the diversity and composition of egg-associated microbiomes. In this study, we used high-throughput amplicon sequencing and quantitative PCR to get a better understanding of the microbiome of insect eggs and how they are established using the Southern green stinkbug Nezara viridula (L.) (Hemiptera: Pentatomidae) as a study object. First, to determine the bacterial community composition, egg masses from two natural populations in Belgium and Italy were examined. Subsequently, microbial community establishment was assessed by studying stinkbug eggs of different ages obtained from laboratory strains (unlaid eggs collected from the ovaries, eggs less than 24 h old, and eggs collected 4 days after oviposition). Both the external and internal egg-associated microbiomes were analyzed by investigating egg washes and surface-sterilized washed eggs, respectively. Eggs from the ovaries were completely devoid of bacteria, indicating that egg-associated bacteria were deposited on the eggs during or after oviposition. The bacterial diversity of deposited eggs was very low, with on average 6.1 zero-radius operational taxonomic units (zOTUs) in the external microbiome and 1.2 zOTUs in internal samples of egg masses collected from the field. Bacterial community composition and density did not change significantly over time, suggesting limited bacterial growth. A Pantoea-like symbiont previously found in the midgut of N. viridula was found in every sample and generally occurred at high relative and absolute densities, especially in the internal egg samples. Additionally, some eggs harbored a Sodalis symbiont, which has previously been found in the abdomen of several insects, but so far not in N. viridula populations. We conclude that the egg-associated bacterial microbiome of N. viridula is species-poor and dominated by a few symbionts, particularly the species-specific obligate Pantoea-like symbiont.

Independent Control Spraying System for UAV-Based Precise Variable Sprayer: A Review

Pesticides are essential for removing plant pests and sustaining good yields on agricultural land. Excessive use has detrimental repercussions, such as the depletion of soil fertility and the proliferation of immune insect species, such as Nilaparvata lunges and Nezara viridula. Unmanned aerial vehicle (UAV) variable-rate spraying offers a precise and adaptable alternative strategy for overcoming these challenges. This study explores research trends in the application of semi-automatic approaches and land-specific platforms for precision spraying. The employment of an autonomous control system, together with a selection of hardware such as microcontrollers, sensors, pumps, and nozzles, yields the performance necessary to accomplish spraying precision, UAV performance efficacy, and flexibility in meeting plant pesticide requirements. This paper discusses the implications of ongoing and developing research. The comparison of hardware, control system approaches, and data acquisition from the parameters of each study is presented to facilitate future research. Future research is incentivized to continue the precision performance of the variable rate development by combining it with cropland mapping to determine the need for pesticides, although strict limits on the amount of spraying make it difficult to achieve the same, even though the quality is very beneficial.

Comparative analysis of detoxification-related gene superfamilies across five hemipteran species

BackgroundHemiptera is one of the most speciose orders of insects, and the most speciose considering Hemimetabola. Through their evolutive history, hemipterans with different feeding habits have adapted to deal with different chemical challenges. Three major gene families are involved in xenobiotic detoxification in insects: the cytochromes P450 (CYPs), carboxyl/cholinesterases (CCEs), and glutathione transferases (GSTs). Here we perform a comparative analysis on the complement of these gene superfamilies across five hemipteran species; four heteropterans (the pentatomid plant feeders Nezara viridula and Halyomorpha halys; the hematophagous Cimex lectularius, Cimicidae, and Rhodnius prolixus, Reduviidae), and one Auchenorrhyncha plant feeder (Nilaparvata lugens).ResultsOur results point to an expansion of several enzyme families associated with xenobiotic detoxification in heteropterans with respect to other species and the existence of a dynamic evolution pattern including CYP3 clan, hormone and pheromone processing class in the CCE superfamily, and sigma class in GST superfamily. Other detoxification-related families are reduced in the hemipteran species analyzed here: reduction or even absence of epsilon class and reduced delta class in GST superfamily; absence of mitochondrial CYP12 family; absence of CYP9 family in CYP3 clan; and reduction or even absence of some dietary/detoxification groups of CCEs. Interestingly, the most polyphagous species analyzed here (H. halys) is also the one that presents the largest repertoire of detoxification enzymes. Gene cluster analysis suggests that this could be due to gene duplication events.ConclusionsThe evolutionary analysis performed here reveals characteristics that are both common and particular for heteropterans. The composition and organization of detoxification-related gene families could shed light on evolutionary forces that shaped their divergence. These families are important for both the detoxification of diet products and for conferring tolerance or resistance to synthetic insecticides. Furthermore, we present the first comprehensive analysis of detoxification gene superfamilies in N. viridula, an understudied species in spite of its economic relevance as a crop pest. The information obtained is of interest for basic insect science as well as for the control of harmful species and the management of insecticide resistance.

Efficacy of Biopesticide Formula Containing Streptomyces sp. and Trichoderma sp. against Southern Green Stink Bug (Nezara viridula) on Soybean (Glycine max L.)

Streptomyces sp. and Trichoderma sp. are soil microorganisms isolated from shallot fields that can act as biological agents and increase crop production. Nezara viridula, the southern green stink bug, is the leading pest of soybean during the generative period, which can cause damage up to 80%. This study aimed to determine the efficacy of a liquid biopesticide formula using a mixture of coconut water and potato extract containing Streptomyces sp. and Trichoderma sp. This study used a randomized block design. The first factor was the time of application and the second factor was the concentration level. There were 8 treatment combinations and 2 controls. Each treatment combination was repeated three times. Probit LC50 and LT50 were performed to determine the effectiveness of biopesticides. The calculation of probit analysis obtained results of 84,443 ppm or about 84% for LC50, while the LT50 analysis obtained results of 4.7 days.

Lethal Concentration and Sporulation by Contact and Direct Spray of the Entomopathogenic Fungus Beauveria bassiana on Different Stages of Nezara viridula (Heteroptera: Pentatomidae).

The southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae) is the most significant pest of soybean worldwide. The present study was conducted to compare the effectiveness of a Delta native strain NI8 of Beauveria bassiana by contact and direct spray on nymphs (2nd to 5th instar) and adults of N. viridula. Water control and four concentrations of B. bassiana were used to evaluate the survival, mortality, and molting percentage and to estimate median lethal concentration (LC50), median lethal sporulation (LS50), and resistance ratio (RR50). Direct spray at all concentrations observed the greatest reduction in survival on all life stages. Mortality and sporulation were positively correlated by concentration, while molting was highly variable with a significantly lower negative correlation on insects that were directly sprayed. Pathogenicity exhibited reduction as young stages developed and emerged to adult. The LC50 (Contact: 612 spores/mm2; Direct spray: 179 spores/mm2) and LS50 (Contact: 1960 spores/mm2 Spray: 3.3 × 106) values showed that adults of N. viridula were highly resistant than any other life stage when exposed to either contact or direct spray. Fourth instar was the most susceptible (LC50: Contact: 18 spores/mm2; Direct spray: 23 spores/mm2) (LS50: Contact: 53 spores/mm2; Direct spray: 26 spores/mm2) followed by second, third, and fifth instars.

Efektivitas Warna dan Ketinggian Perangkap terhadap Nezara viridula L. pada Tanaman Kacang Panjang (Vigna sinensis L)

An important pest that attacks long bean plants is the green ladybug (Nezara viridula L.). Green ladybug attacks cause the young pods to become empty and deflated, because the seeds do not form and the pods fall. Several field tests showed that yield loss by one adult N. Viridula per two plants caused pod damage by 49%. The aim of the study was to determine the color and height of the traps that were effective in trapping the green ladybug (Nezara viridula L.). The study was conducted in Taeno hamlet, Rumah Tiga Village, Teluk Ambon District from April to June 2022. The study used a Randomized Block Design (RAK) with 2 treatments. The first treatment was a trap color consisting of 3 levels, namely red, yellow and green. The second treatment was the height of the trap which consisted of 3 levels, namely the height of the trap 1 m, 1.5 m, and 2 m above ground level. The results obtained information that the interaction between the red trap color and the 1.5 m trap height had a significant effect on the number of green ladybug populations trapped in the 1st to 4th observations. -3 is found in the use of yellow traps, while in the 4th observation the interaction between green traps with a trap height of 1.5 m.

Efektivitas Warna dan Ketinggian Perangkap terhadap Nezara viridula L. pada Tanaman Kacang Panjang (Vigna sinensis L)

An important pest that attacks long bean plants is the green ladybug (Nezara viridula L.). Green ladybug attacks cause the young pods to become empty and deflated, because the seeds do not form and the pods fall. Several field tests showed that yield loss by one adult N. Viridula per two plants caused pod damage by 49%. The aim of the study was to determine the color and height of the traps that were effective in trapping the green ladybug (Nezara viridula L.). The study was conducted in Taeno hamlet, Rumah Tiga Village, Teluk Ambon District from April to June 2022. The study used a Randomized Block Design (RAK) with 2 treatments. The first treatment was a trap color consisting of 3 levels, namely red, yellow and green. The second treatment was the height of the trap which consisted of 3 levels, namely the height of the trap 1 m, 1.5 m, and 2 m above ground level. The results obtained information that the interaction between the red trap color and the 1.5 m trap height had a significant effect on the number of green ladybug populations trapped in the 1st to 4th observations. -3 is found in the use of yellow traps, while in the 4th observation the interaction between green traps with a trap height of 1.5 m.

OCCURANCE OF N. viridula (Order- HEMIPTERA)) FROM SANGOLA, DIST.SOLAPUR (MS)

Nezara viridula (L.) is a cosmopolitan, polyphagous heteropteran that causes economic damage to many crop species. It is predominant in most of the warmer regions, damaging a wide variety of fruits. In the present study, N.viridula insect pest was recorded for the first time. It belongs to the family Pentatomidae . This is a polyphagus vegetable pest that mainly occurs on brinjal and okra vegetable crops. It is a sap-sucking insect pest that causes severe damage and economic losses. Key words: Occurance, N. viridula, vegetables, insect pest.

Mechanical interaction of the egg parasitoid Anastatus bifasciatus (Hymenoptera: Eupelmidae) with artificial substrates and its host egg

Egg parasitoids play an important role in biological control of pest species attacking and killing their hosts at an early stage of their development. During the antagonistic coevolution with their hosts, egg parasitoids have developed a great ability to locate their host using chemical cues. A considerable amount of literature is available on this topic, while nothing is known about a possible adaptation of egg parasitoids to topography and mechanical properties of egg surface features and its shape when attaching to the host egg for oviposition. In the present investigation, the attachment ability of adults of both sexes of the egg parasitoid Anastatus bifasciatus (Hymenoptera: Eupelmidae) to artificial (polishing paper, flat glass, glass beads as dummies of the host egg) and natural surfaces (eggs of Halyomorpha halys and Nezara viridula, both Heteroptera: Pentatomidae), with different roughness and wettability, was measured using centrifugal force tester and traction force experiments. The parasitoid attachment devices and the egg surfaces were examined under cryo scanning electron microscope, wettability and roughness of natural and artificial substrates were characterised. We detected differences in the attachment devices and attachment ability of the two sexes. The collected data revealed a special ability of the female to attach to the eggs of the host species, thus suggesting an adaptation of the A. bifasciatus female to the surface features of the eggs during oviposition.

Complete genome analysis of a novel chuvirus from a southern green stink bug (Nezara viridula).

A novel chuvirus from a southern green stink bug (Nezara viridula) was identified by RNA sequencing in this study and was tentatively named "Ningbo southern green stink bug chuvirus 1" (NBSGSBV-1). The complete genome sequence of NBSGSBV-1 consists of 11,375 nucleotides, and the genome was found to be circular by 'around-the-genome' reverse transcription polymerase chain reaction (RT-PCR) and Sanger sequencing. Three open reading frames (ORFs) were predicted in the NBSGSBV-1 genome, encoding a large polymerase protein (L protein), a glycoprotein (G protein), and a nucleocapsid protein (N protein). A phylogenetic tree was constructed based on all of the currently available RNA-dependent RNA polymerase amino acid sequences of viruses of the family Chuviridae, and NBSGSBV-1 was found to cluster together with Sanya chuvirus 2 and Hubei odonate virus 11, indicating that NBSGSBV-1 might belong to the genusOdonatavirus. Five conserved sites were identified in the L proteins of NBSGSBV-1 and other chuviruses. The abundance and characteristics of the NBSGSBV-1-derived small interfering RNAs suggested that NBSGSBV-1 actively replicates in the host insect. To the best of our knowledge, this is the first report of a chuvirus identified in a member of the insect family Pentatomidae. The discovery and characterization of NBSGSBV-1 will help us to understand the diversity of chuviruses in insects.

Effect of Two Strains of Beauveria bassiana on the Fecundity of Nezara viridula L. (Heteroptera: Pentatomidae)

The southern green stink bug (SGSB) Nezara viridula (L.) (Heteroptera: Pentatomidae), has become a significant pest of soybean and cotton in southern Central America and in the lower mid-southern U.S. A laboratory colony of SGSB was used to evaluate the effect of two isolates of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae) including the commercial strain GHA and the Mississippi Delta native NI8 strain on the fecundity of this pest. Water control, Tween-80, and four concentrations of each strain (n × 104, 105, 106, and 107) were evaluated. Both native and commercial isolates with the highest concentrations were susceptible to the SGSB. Females, however, were much more pathogenic to both strains than males. Lethal concentration of the native strain (236 spores/mm2) was 1.4-fold lower (326 spores/mm2) than the GHA strain for females evaluated 20 d post-exposure. Greater concentrations (1.1 × 107 spores/mm2, 5.2 × 106 spores/mm2) were required to kill males with both strains native and commercial, respectively. For controls and lower concentrations, cumulative fecundity ranged from 1178 to 2082 eggs/10 couples/life reproduction, compared with 597 and 673 eggs/10 couples sprayed (n × 106 and 107) with the native NI8, respectively, and 386 eggs/10 couples sprayed (n × 107) with the commercial GHA.

Feeding on soybean crops changed gut bacteria diversity of the southern green stinkbug (Nezara viridula) and reduced negative effects of some associated bacteria.

The southern green stinkbug (Nezara viridula) is a mayor pest of soybean. However, the mechanism underlying stinkbug resistance to soybean defenses is yet ignored. Although gut bacteria could play an essential role in tolerating plant defenses, most studies testing questions related to insect-plant-bacteria interactions have been performed in laboratory condition. Here we performed experiments in laboratory and field conditions with N. viridula and its gut bacteria, studying gut lipid peroxidaxion levels and cysteine activity in infected and unifected nymphs, testing the hypothesis that feeding on field-grown soybean decreases bacterial abundance in stinkbugs. Gut bacterial abundance and infection ratio were higher in N. viridula adults reared in laboratory than in those collected from soybean crops, suggesting that stinkbugs in field conditions may modulate gut bacterial colonization. Manipulating gut microbiota by infecting stinkbugs with Yokenella sp. showed that these bacteria abundance decreased in field conditions, and negatively affected stinkbugs performance and were more aggressive in laboratory rearing than in field conditions. Infected nymphs that fed on soybean pods had lower mortality, higher mass and shorter development period than those reared in the laboratory, and suggested that field conditions helped nymphs to recover from Yokenella sp. infection, despite of increased lipid peroxidation and decreased cysteine proteases activity in nymphs' guts. Our results demonstrated that feeding on field-grown soybean reduced bacterial abundance and infection in guts of N. viridula and highlighted the importance to test functional activities or pathogenicity of microbes under realistic field conditions prior to establish conclusions on three trophic interactions. © 2022 Society of Chemical Industry.

Release strategies of Trissolcus basalis (Scelionidae) in protected crops against Nezara viridula (Pentatomidae): Less is more

Nezara viridula is responsible for significant damage on cucumber, eggplant and tomato. This stink bug feeds on plant tissue causing desiccation of apices and flower bud drop; it also attacks fruits, causing deformation. Insecticides registered to control N. viridula are not compatible with natural enemies, as they disrupt integrated pest management. In a two-year trial, we evaluated the efficacy of the egg parasitoid Trissolcus basalis to control N. viridula. We tested four combinations of quantity and frequency of release of the parasitoid in the greenhouse. Each combination was repeated four times and compared to a positive control without parasitoid introduction. We observed effective control of N. viridula with the four strategies tested, but the best cost/benefit ratio was obtained with the release of 1 parasitoid/m2/week. The parasitism efficiency was relatively high for each strategy considered, ranging from 89 to 99%, which demonstrated a strong regulation impact on the stink bug population. Total parasitism ranged from 47 to 68%, which indicated relatively good activity and efficiency of the parasitoid, and led to a significant reduction of the damage in comparison to the control. Desiccated apices were reduced by 45 to 71% and flower bud drop by 32 to 60%. The highest damage reduction was obtained by releasing 1 parasitoid/m2/week. Hence, T. basalis is a good candidate for the biological control of N. viridula in protected crops. Surprisingly, the best regulation was not obtained when the highest quantity of parasitoids was released. Implications of intra-specific competition are discussed.

Combination of UV and green light synergistically enhances the attractiveness of light to green stink bugs Nezara spp

The southern green stink bug Nezara viridula and its congener N. antennata are important agricultural pests worldwide. These species show positive phototaxis and their compound eyes have high sensitivity to UV and green lights. The attractiveness of monochromatic UV, green lights and combined UV and green light to stink bugs was investigated under field conditions. The number of stink bugs caught increased with the number of UV LEDs, but very few bugs were caught using green light, irrespective of the number of LEDs. However, the most stink bugs were caught when both colors were combined. These results indicate that monochromatic green light is less attractive to Nezara bugs, but when mixed with UV light, it synergistically enhances the attractiveness of UV light. This finding contributes to the construction of reliable and highly specific light traps to monitor Nezara bugs. The addition of green light hardly affected the attractiveness of the UV light to other insects, such as Anomala beetles, which are often caught in light traps. We conclude that the spectral composition of light that is attractive to nocturnal insects depends on the species, hence it is possible to make ecologically friendly light traps that are target specific.

Seasonal incidence and effect of weather parameters on insect pests of linseed

The most destructive enemy of linseed in India are insect pests. Twelve insect pests that caused damage in linseed under Hyderabad (India) conditions were recorded during 2020-2021. Percent incidence and population (per 10 plants) of Liriomyza trifolii varied from43.2±7.20 to 69.7±5.53 and 0 to 2.8±0.20, respectively. Populations (per 10 plants) of Bemisia tabaci, leafhopper, Nezara viridula and Creontiades sp. reached maximum during first week of January 2021 (22.2±3.18), last week ofJanuary 2021 (13.6±0.68), first week ofJanuary 2021 (2.6±2.36) and last week of February 2021 (2.2±0.37), respectively. Dasyneura lini population (per 10 plants) varied between 0 to 2.2±0.49 and reached maximum during second week of February 2021 (2.2±0.49). Spodoptera exigua population reached maximum during third week of January 2021 (2.0±0.89 per 10 plants), whereas population (per 10 plants) of Helicoverpa armigera reached highest during third week ofJanuary 2021 (2.6±0.98). Other insect pests such as Aulacophora sp., Monolepta signata, Hyposidra talaca and tussock caterpillar also caused more damage to linseed. Among abiotic factors, the maximum temperature showed a negative correlation with all insect pests except Creontiades sp. and H. talaca. The abiotic factors jointly had a highly significant impact on population of insect pests. The model to predict insect pests incidence in linseed was developed by linear regression model which would offer forecasting for short term period.

Citizen Science Meet South American Tachinids: New Records of Feather-Legged Fly Trichopoda (Galactomyia) pictipennis Bigot (Diptera: Tachinidae) from Chile.

The species of Gymnosomatini (Diptera: Tachinidae) are specialized to attack stink bugs (Hemiptera: Pentatomidae). Some of these flies, such as those in the genus Trichopoda Berthold, are conspicuous and represent target species to study with citizen science. Here we report for the first time the distribution range of T. (Galactomyia) pictipennis Bigot, a newly introduced biological control species of tachinid for use against stink bugs in Chile using data obtained through the citizen science method. Additionally, we update the distribution of T. arcuata (Bigot), a native biological control species of tachinid, and assess the grade of overlap between the flies and their main stink bug hosts. We obtained data regarding the occurrence of flies and stink bugs from the citizen science program "Moscas Florícolas de Chile," from Facebook groups, and from iNaturalist. We standardized our data to avoid temporal, spatial, and geographic biases. We report the extent of occurrence (EOO) and area of occupancy (AOO) for each fly and stink bug species. The EOOs for T. pictipennis and T. arcuata are 85,474 km2 and 20,647 km2 through central Chile ecosystems, respectively. The EOO of T. arcuata is overlapped by 53% with the introduced species. Trichopoda pictipennis has a high percentage of overlap with the EOO of Nezara viridula Linnaeus (61%), whereas T. arcuata has low percentages of overlap with different native Acledra species and with N. viridula. We discuss the potential of citizen science to detect (1) areas with higher diversity or gaps of occurrences, (2) new biological control agents, (3) prey records, (4) negative impacts on non-target species, (5) changes in composition at long-term, and (6) areas to promote conservation biological control in agricultural landscapes.

RNAi-induced knockdown of white gene in the southern green stink bug (Nezara viridula L.)

The southern green stink bug (SGSB) Nezara viridula L. is one of the most common stink bug species in the United States and can cause significant yield loss in a variety of crops. A suitable marker for the assessment of gene-editing tools in SGSB has yet to be characterized. The white gene, first documented in Drosophila, has been a useful target to assess the efficiency of introduced mutations in many species as it controls pigmentation processes and mutants display readily identifiable phenotypes. In this study we used the RNAi technique to investigate functions and phenotypes associated with the white ortholog in the SGSB and to validate white as a marker for genetic transformation in this species. This study revealed that white may be a suitable marker for germline transformation in the SGSB as white transcript knockdown was not lethal, did not impair embryo development and provided a distinguishable phenotype. Our results demonstrated that the white ortholog in SGSB is involved in the pathway for ommochrome synthesis and suggested additional functions of this gene such as in the integument composition, management of hemolymph compounds and riboflavin mobilization.

Contrasting reproductive traits of competing parasitoids facilitate coexistence on a shared host pest in a biological control perspective

BACKGROUNDInterspecific competition in insect parasitoids is an important ecological phenomenon that has relevant implications for biological pest control. To date, interspecific intrinsic (=larval) competition has been intensively studied, while investigations on extrinsic (=adult) competition have often lagged behind. In this study we examined the role played by parasitoid reproductive traits and host clutch size on the outcome of extrinsic competition between Trissolcus basalis (Wollaston) and Ooencyrtus telenomicida (Vassiliev), two egg parasitoids of the pest Nezara viridula (L). Laboratory experiments were conducted by allowing both parasitoid species to exploit an egg mass made of 10, 20, 30, or 40 hosts through single or simultaneous releases. Furthermore, under field conditions, egg masses consisting of 10 or 40 hosts were exposed in a tomato crop in order to validate laboratory investigation.RESULTSThe results show that the egg mass size is an important predictor of extrinsic competition in our study system as a higher proportion of T. basalis emerged from large egg masses, while O. telenomicida dominated in small egg masses. Analysis of reproductive traits of parasitoid species indicates that T. basalis has superior abilities in host exploitation compared with O. telenomicida.CONCLUSIONSWe found that contrasting reproductive traits of two competing egg parasitoid species facilitate coexistence on a shared stink bug host. This work also highlights the importance to consider extrinsic competitive interactions between parasitoid species in a biological control perspective. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Attraction of Egg Parasitoids Trissolcus mitsukurii and Trissolcus japonicus to the chemical cues of Halyomorpha halys and Nezara viridula.

Simple SummaryWhen an alien species reaches a new environment, the natural enemies present in that habitat might fail to regulate its population as they might not be host-adapted. Hence, the best solution might be the use of alien biological control agents that are co-evolved with the exotic pest in question. This is the case of Halyomorpha halys, which is native to Asia and has recently invaded Europe and the Americas. Trissolcus japonicus and Trissolcus mitsukurii are among its main parasitoids. Adventive populations of the latter were found in Northern Italy, suggesting its employment within augmentative biological control. Homologous programs with T. japonicus are already ongoing in Italy. This procedure implies releasing the parasitoid to increase its population and spread to new areas invaded by H. halys. However, a fundamental aspect that must be investigated is the risk-assessment beforehand, i.e., the systematic process of identifying the hazard associated with such a procedure. In this context, the preference of T. japonicus and T. mitsukurii between two stinkbugs was evaluated in this study. We found that T. japonicus preferred the naturally released traces of H. halys while T. mitsukurii exhibited a higher preference for the natural and synthetic chemical cues of N. viridula.Trissolcus mitsukurii and Trissolcus japonicus are two Asian egg parasitoids associated with different pentatomids such as Halyomorpha halys. Adventive populations of T. mitsukurii were found in Northern Italy, suggesting its employment as a biological control agent (BCA) against H. halys. Nevertheless, to reduce the latter’s population, T. japonicus was released in Italy. Releasing an exotic parasitoid requires investigating the interaction between the BCA and the environment to avoid negative impacts on the entomofauna of the new habitat. Trissolcus mitsukurii is mainly associated with Nezara viridula in its native area. Therefore, we investigated and compared the ability of female T. mitsukurii and T. japonicus to distinguish between naturally released cues of H. halys and N. viridula. A single parasitoid was exposed to contact kairomones of both pests to evaluate its modifications in orthokinetic and locomotory behaviour. The behaviour of female T. mitsukurii was also tested on synthetic compounds simulating the cues of the two pentatomids. When naturally released cues were used, T. japonicus preferred the traces of H. halys, while T. mitsukurii preferred N. viridula’s cues. Moreover, the attraction of T. mitsukurii to N. viridula’s cues was confirmed with synthetic cues. Additional studies are needed to judge if this parasitoid can be used as a BCA.