Nezara Viridula Research Articles

Performance of soybean cultivars in integrated pest management in lowland agroecosystem

Soybean crop represents a large economic share in the Brazilian agricultural production. In Rio Grande do Sul (RS), with each new crop cycle there is an increase in the area under cultivation. In the lowland environment, the crop covers 5.4 million hectares, corresponding to about 20% of the State total area. Using transgenic cultivars whose main advantage is controlling target insects, as well as the reduced number of insecticide applications throughout the crop can be a viable alternative. However, the high cost of transgenic seed is considered as the main disadvantage in adopting this technology. The objective of this study was to evaluate the performance of cultivars RR1 and RR2 in relation to the occurrence of caterpillars and stink bugs, as well as to evaluate the production cost. The experiment was set up at Embrapa Clima Temperado in the crop seasons of 2014/2015 and 2015/2016, with conventional cultivars (BMX Potencia (RR1 6.7)) and Bt isolines (BMX Ponta (IPRO 6.6)) and BMX Vanguarda (IPRO 6.0)). BMX Potencia cultivar showed a higher incidence of defoliating caterpillars and Nezara viridula stinkbug, but it is the most indicated cultivar, among those evaluated, for the south lowland environment of RS, due to its yield and profitability.

Entrapment of Bradysia paupera (Diptera: Sciaridae) by Phaseolus vulgaris (Fabaceae) plant leaf

Flies of the genus Bradysia (Diptera, Sciaridae) are considered as major insect pests of greenhouse-grown horticultural crops. The ability of hooked trichomes of the French bean Phaseolus vulgaris to impale and entrap herbivorous insects thus resulting in insect reduced longevity, reproduction and larval mortality is well known. The present study investigates under laboratory conditions the ability of hooked trichomes of bean leaves to entrap fungus gnats Bradysia paupera, in order to estimate the reduction of their population. We characterized the entrapment mechanism of hooked trichomes towards B. paupera using cryo-scanning electron microscopy, and evaluated the silicon distribution in hooked trichomes with the energy dispersive X-ray microanalysis. We evaluated the trapping efficiency of hooked trichomes in fertilized and unfertilized bean plants towards B. paupera, in comparison with insects feeding on the plant leaf such as black bean aphid Aphis fabae and young stages of the southern green stinkbug Nezara viridula. For B. paupera, we recorded about 30% of entrapped insects in unfertilized plants. Considering the number of entrapped insects in relation to the leaf surface, the percentage of entrapped insect was higher in unfertilized than in fertilized plants having lower density of hooked trichomes. The presence of P. vulgaris plants in greenhouses could represent a useful method in integrated pest management to reduce Bradysia spp. population.

Intercropping garlic at different planting times and densities for insect pest or crop yield and value management in tobacco fields

AbstractAlthough the densities of tobacco pests have been decreased in garlic‐tobacco fields, further studies are needed to judge the effects of garlic transplanting densities or times on tobacco pests in tobacco fields. Therefore, field experiments were conducted in Liancheng County in Longyan City, Fujian Province, in China in 2014 and 2015. Myzus persicae (Sulzer) abundance, the species or abundance ratios of enemies and pests, the intercropping effects and the tobacco yield and crop value showed that the effects of transplanting tobacco 10 days after garlic transplantation at a density of 5.85 individual plants per square meter on pests were stronger than those of other treatments. Aphid abundance was significantly lower in transplanting tobacco 10 days after garlic transplantation at a density of 5.85 individual plants per square meter than in the other treatments. The ratio between enemies and pests in transplanting tobacco 10 days after garlic transplantation at a density of 5.85 individual plants per square meter was higher than those in the other treatments. The intercropping effects of transplanting tobacco 10 days after garlic transplantation at a density of 5.85 individual plants per square meter on Myzus persicae, Spodoptera litura (Fabricius), Heliothis assulta Guenee and Nezara viridula Linnaeus were significantly stronger than those of the other treatments, whereas the effects of transplanting tobacco 15 days after garlic transplantation at a garlic density of 5.85 individual plants per square meter on Agrotis ypsilon (Rottemberg) were significantly stronger. Additionally, the yield and crop value of transplanting tobacco 10 days after garlic was transplanted at a density of 5.85 individual plants m−2 were higher than those of the other treatments. Therefore, our study demonstrated that the model of transplanting tobacco 10 days after garlic was transplanted at a density of 5.85 individual plants m−2 is an optimal management strategy to control flue‐cured tobacco pests and to acquire higher crop yield in garlic‐tobacco fields.

A stereoisomer of JHSB3 with 10S-configuration, 10S-JHSB3, biosynthesized by the corpus allatum of the brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae)

The products released by the corpus allatum (CA), an endocrine gland producing juvenile hormone (JH), were analyzed in three species of stink bugs. Liquid chromatography–mass spectrometry (LC–MS) analysis of the CA products from female adults of Halyomorpha halys (Stal), Nezara viridula (Linnaeus), and Nezara antennata Scott (Hemiptera: Pentatomidae) revealed that the CA biosynthesized JH III skipped bisepoxyside (JHSB3) in all three species. In H. halys, in addition to JHSB3, the CA also produced its stereoisomer, 10S-JHSB3. A bioassay focusing on the number of antennal segments was adopted to examine biological activity of these products. When last instar nymphs were treated with either of the two JHs, they emerged as adults bearing nymphal type antennae with four segments in a dose-dependent fashion, indicating that both JHSB3 and 10S-JHSB3 had the JH activity in H. halys. Therefore, for the first time, 10S-JHSB3 in H. halys was found to be a naturally occurring JH molecule with 10S-configuration.

Feeding Behavior of Nezara viridula First Instars: EPG Analysis and Effect of Food Availability on Subsequent Development

Assertions that first-instar pentatomids “do not feed” are pervasive in the literature. Recent research using rifampicin-resistant marked bacteria demonstrated that first-instar southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), ingest from green bean. The technique of electropenetrography (EPG), coupled with histology, has allowed researchers to elucidate feeding behavior within plant tissue, and recordings of several species (including N. viridula) have shown that internal stylet probes of adults and late-instar nymphs may terminate in xylem as well as in seed endosperm, inner pod wall, or stem parenchyma. The seeming contradiction regarding “feeding” could be explained if first instars were simply hydrating from plant tissue to maintain water balance. In this study, first-instar N. viridula were supplied with either water or green bean, and subsequently given a traditional rearing diet (green bean and peanut) from second instar onward. We noted aggregations of first instars forming on water wicks and on beans along the carpellary bundles and at both tips. Availability of food (green bean) in first instar did not affect subsequent development. Using EPG, we recorded first-instar N. viridula probing on soybean leaves and found the primary waveform to be xylem ingestion. Probing and ingestion behavior did not differ between first instars previously exposed to high and moderate humidity conditions. We conclude that these insects ingest from xylem, but nutrients other than water are not required in the first instar for successful nymphal development.

A transcriptomic and proteomic atlas of expression in the Nezara viridula (Heteroptera: Pentatomidae) midgut suggests the compartmentalization of xenobiotic metabolism and nutrient digestion

BackgroundStink bugs are an emerging threat to crop security in many parts of the globe, but there are few genetic resources available to study their physiology at a molecular level. This is especially true for tissues such as the midgut, which forms the barrier between ingested material and the inside of the body.ResultsHere, we focus on the midgut of the southern green stink bug Nezara viridula and use both transcriptomic and proteomic approaches to create an atlas of expression along the four compartments of the anterior-posterior axis. Estimates of the transcriptome completeness were high, which led us to compare our predicted gene set to other related stink bugs and Hemiptera, finding a high number of species-specific genes in N. viridula. To understand midgut function, gene ontology and gene family enrichment analyses were performed for the most highly expressed and specific genes in each midgut compartment. These data suggested a role for the anterior midgut (regions M1-M3) in digestion and xenobiotic metabolism, while the most posterior compartment (M4) was enriched in transmembrane proteins. A more detailed characterization of these findings was undertaken by identifying individual members of the cytochrome P450 superfamily and nutrient transporters thought to absorb amino acids or sugars.ConclusionsThese findings represent an initial step to understand the compartmentalization and physiology of the N. viridula midgut at a genetic level. Future studies will be able to build on this work and explore the molecular physiology of the stink bug midgut.

First detection of the Nearctic parasitoid species Trichopoda pennipes (Fabricius) (Diptera: Tachinidae) in Egypt

Specimens of the feather-legged fly, Trichopoda pennipes (Fabricius) (Diptera: Tachinidae), which parasitize adults of the southern green stink bug Nezara viridula (L.) (Hemiptera: Pentatomidae), have been detected in Giza, Egypt. This is the first record of this Nearctic species with its genus (Trichopoda) and its tribe (Gymnosomatini) in Egypt. T. pennipes is known as an endoparasitoid of many true bug hosts, the pests of various crops, and it could have a potentiality to control these pests in addition to N. viridula, which is known to be its principal host. Taxonomy and diagnosis of the detected parasitoid species in addition to a checklist of the subfamily Phasiinae in Egypt are provided. Colored photographs of the parasitoid larval and adult stages and parasitized host are provided as well.

Determination of Agronomical Characters as the Resistance Attributes of Twenty Soybean Varieties to Stink Bug (Nezara viridula L.)

The research was conducted to study the agronomical characters as the resistance attributes of twenty soybean varieties to Nezara viridula. The results showed that the twenty soybean varieties had a different response to stink bug infestation. Gepak Kuning, Seulawah, and Sinabung were resistant to stink bug, while Argomulyo were highly susceptible, and Grobogan and Malabar were susceptible. Besides resistance to stink bug, Sinabung also had the highest seed yield (2.95 t/ha). The seed yield of Gepak Kuning and Seulawah were not high, i.e. 2.20 and 1.82 t/ha respectively. The three highly susceptible or susceptible varieties also showed the lowest seed yield, i.e. 0.68 t/ha (Argomulyo), 0.42 t/ha (Grobogan) and 0.99 t/ha (Malabar). The negative correlation was shown between resistance to pest with days to maturity, duration of the reproductive phase, the number of unfilled pods, and weight of 100 seeds. Seed yield also had a negative correlation with duration of reproductive phase and weight of 100 seeds. It indicated that varieties with short duration of reproductive phase and small seed size were preferred by Nezara viridula as food sources. Therefore, these two characters can be used to determine the soybean resistance to Nezara viridula.

The Phytochemical Composition of Melia volkensii and Its Potential for Insect Pest Management.

Due to potential health and environmental risks of synthetic pesticides, coupled with their non-selectivity and pest resistance, there has been increasing demand for safer and biodegradable alternatives for insect pest management. Botanical pesticides have emerged as a promising alternative due to their non-persistence, high selectivity, and low mammalian toxicity. Six Meliaceae plant species, Azadirachta indica, Azadirachta excelsa, Azadirachta siamens, Melia azedarach, Melia toosendan, and Melia volkensii, have been subject to botanical pesticide evaluation. This review focuses on Melia volkensii, which has not been intensively studied. M. volkensii, a dryland tree species native to East Africa, has shown activity towards a broad range of insect orders, including dipterans, lepidopterans and coleopterans. Its extracts have been reported to have growth inhibiting and antifeedant properties against Schistocerca gregaria, Trichoplusia ni, Pseudaletia unipuncta, Epilachna varivestis, Nezara viridula, several Spodoptera species and other insect pests. Mortality in mosquitoes has also been reported. Several limonoids with a wide range of biological activities have been isolated from the plant, including volkensin, salannin, toosendanin, trichilin-class limonoids, volkendousin, kulactone among others. This paper presents a concise review of published information on the phytochemical composition and potential of M. volkensii for application in insect pest management.

Synchronized hatching as a possible strategy to avoid sibling cannibalism in stink bugs

In some animals, timing of egg hatching is adjusted in response to cues from clutch mates to synchronize hatching within a clutch and this typically facilitates mass migration of hatchlings from their natal clutch. A recent study in eight species of Pentatomidae revealed that four species show synchronized hatching due to responses to earlier-hatched siblings, by comparing temporal hatching patterns between intact clutches and eggs individually detached from clutches. However, hatchlings of Pentatomidae do not migrate from their natal clutch immediately. In the present study, using the same eight species, we explored the evolutionary reason for the synchronized hatching in Pentatomidae. In all of the species examined except one non-synchronized species, Eurydema rugosum, hatchlings showed egg feeding behavior with greatly different time of onset. The highly synchronized species, Halyomorpha halys and Nezara viridula, had the time of onset of egg feeding earlier than in the other species. In these two species, based on the hatching patterns of eggs individually detached from their clutches, we concluded that eggs can be cannibalized by their earlier-hatched siblings unless they hatch in response to siblings. On the other hand, this was not the case in the moderately synchronized species, Piezodorus hybneri and Plautia stali. In the other three non-synchronized species, Aelia fieberi, Dolycoris baccarum, and Palomena angulosa, eggs seemed not to incur a risk of cannibalism. In intact H. halys clutches, almost no eggs were cannibalized by siblings. In conclusion, synchronized hatching serves as a possible strategy to avoid sibling cannibalism in Pentatomidae, although it can also have some other functions. Eggs should often be able to control when to hatch in response to environmental factors affecting survival of eggs or hatchlings. Species of various taxa show responses to siblings in the same clutch to achieve synchronized hatching among the siblings. It is typically recognized that such synchronized hatching is required so that hatchlings leave their natal clutch together, which serves, for example, to reduce the risk of being preyed on by predators. Here, we present evidence supporting that synchronized hatching observed in some stink bugs helps eggs to avoid being cannibalized by their earlier-hatched siblings. We also show that other stink bugs with no synchronized hatching have no or little risk of sibling egg cannibalism. This study deepens our knowledge that the synchronized hatching can function in various social contexts with siblings.

Population dynamics of stink bugs (Heteroptera: Pentatomidae) associated at various soybean phenological stages

The populations of phytophagous stink bugs may vary with cultivar and crop management. The aim of this study was to know the population dynamics of stink bugs Euschistus heros, Nezara viridula, and Piezodorus guildinii at different soybean phenological stages. Samples of each stink bug species were done in three soybean (Syn1059, P97R01, and M7110IPRO) cultivars conducted in two seasons. For three cultivars and two seasons, E. heros was the most abundant, followed by P. guildinii and N. viridula. The soybean phenology influenced stink bug population dynamics, mainly in the inflorescence emergence, flowering, development of fruits and seeds, and ripening of fruits and seeds stages. For soybean cultivars, Syn1059 and M7110IPRO were high colonized by stink bugs, while colonization in P97R01 was low suggesting susceptible differences between cultivars. The relationship between stink bug populations and soybean phenology can provide information to monitoring pest populations during these stages.

Transcription and Activity of Digestive Enzymes of Nezara viridula Maintained on Different Plant Diets.

Nezara viridula is a polyphagous stink bug that feeds on crops of economic importance such as corn, soybean and cotton. To increase understanding of the ability of this pest insect to feed on such diverse cropping systems, we analyzed the impact of an exclusive diet of corn or green bean on the enzymatic activity and transcriptomic profile of digestive enzymes. Growth rate and survival were reduced when insects were reared exclusively on green bean compared to corn. However, the overall protease and nuclease activity profiles were comparable between the two treatments. Distinct differences in inhibitor sensitivity and activity were seen in some cases, particularly for serine proteases in some regions of the midgut. The transcription profiles from N. viridula fed on corn versus green bean were distinct on principal component analysis of RNA-seq data. While specific transcripts differentially transcribed according to diet and across several tissues were identified, a large number of these transcripts remain unannotated. Further annotation for identification of these genes will be important for improved understanding of the remarkable polyphagy of N. viridula.

Development of the elements of the biological system for protecting crops against the southern green stink bug Nezara viridula L. (Hemiptera: Pentatomidae) in Krasnodar Krai

The article considers the issues related to the development of the methods of biological crop protection against the adventive species of pentatomides (Pentatomidae, Hemiptera) – the southern green stink bug Nezara viridula L. 1758. One of the main factors contributing to the significant spread of this multinucleated pest is the lack of effective control systems of this species, in particular, poor knowledge of local entomophages species. A number of the biological peculiarities of a stinkbug has been studied. For the first time in the Russian Federation, infection of the N. viridula eggs with the entomophage Trissolcus basalis Woll. 1858 (Hymenoptera: Scelionidae) was determined We found that to control Nezara in such crops as soybeans, tomatoes and tobacco, it is possible to use the Fitoverm-M preparation (active ingredient – aversectin-C, 2 g/l).

Nutritional Ecology of the Southern Green Stink Bug <i>Nezara viridula</i> (Hemiptera: Pentatomidae) on Selected Varieties of Cowpea and Tomato

Cowpea, Vigna unguiculata (L.) Walp. (Fabales: Fabaceae), and tomato, Solanum lycopersicum L. (Solanales: Solanaceae), are two economically important crops in the southern United States. The southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae) is a highly polyphagous pest that attacks a wide range of crops including cowpea and tomato causing a reduction in yield and produce quality. Considering the damage and the associated losses in cowpea and tomato production by this and other pests, as well as the demand for reduced use of pesticides, there is a need to cultivate varieties that are resistant to N. viridula. One key indicator of resistance is host nutritional availability and adequacy. This study evaluated the effect of two selected varieties of cowpea and tomato on the growth and development of N. viridula under laboratory conditions as a first step towards the assessment of nutritional adequacy of both crops. We carried out feeding experiments to compare food utilization and suitability by various life stages of N. viridula. The food substrates tested included fresh immature cowpea pods, fresh cowpea seeds, dry cowpea seeds and newly ripened tomato fruits. Overall, mean nymphal mortality was less when reared on cowpea (63.7±2.9%) than tomato (83.0±1.8%). Nymphs required less time to complete development on cowpea (27.8±2.8d) than on tomato (45.0±3.9d). Fresh body weight at adult emergence was greater on cowpea (132.3±12.1mg) than tomato (83.9±1.5mg). Consumption index (CI) and growth rate (GR) were higher on cowpea (CI: 22.0 ±1.3; GR: 2.1±0.3) than tomato (CI: 8.7±1.4; GR: 0.9±0.1). Collectively, these results suggest that cowpea provided a more suitable nutritional substrate for nymphal development. Many small vegetable growers cultivate both crops.

Ekonomski značajne štetočine povrtarskih useva u Smederevskoj Palanci

The aim of this research was to determine insect pests on vegetable crops in Smederevska Palanka area. By using standard methods, equipment and tools, insect pests that caused significant and less significant damages have been determined on vegetable crops: pepper, tomato, cucumber, melon, zucchini, cabbage, pea, bean, spinach and beet at the arable area at the Institute for Vegetable Crops. The most significant insect pests, causing the most damages were Frankliniella occidentalis and Tuta absoluta, and also several species of aphids (Brevicoryne brassicae, Myzus persicae, Aphis gossypii, Aphis fabae and Macrosiphum euphorbiae), stink bugs (Nezara viridula, Eurydema spp.) and flea beetle (Phyllotreta spp.). These insects caused direct and indirect damages. The most significant damages have been noted in green houses due to favourable conditions for insect reproduction and sufficient food supplies.

MAXIMIZING LAND USAGE AND PROFITABILITY BY RELAY INTERCROPPING COTTON WITH SOME CROPS AND ITS RELATION TO INSECT CENSU

A two-years study was carried out at Sids Agricultural Research Station, Beni-Sweif government, Agricultural Research Center (ARC), Egypt, during 2016/2017 and 2017/2018 seasons to evaluate response of Egyptian cotton traits to different intercropping systems with some wheat cultivars and its relationship with land usage ,farmer's benefit and insect infestation. The treatments were the combination between three wheat cultivars (Sids 4, Sids 12 and Misr 2) and three intercropping systems (wheat/cotton ‘CS1’, wheat + onion (green)/cotton ‘CS2’ and wheat + onion(green) /cotton + sesame ‘CS3’). The treatments were compared in a split plot design with three replications. The results showed that Wheat cultivar Misr 2 gave higher plant , biological and grain yields(10.41, 7.09, 19.71and 18.09) per fad but it had lower grains weight per spike than others in both seasons. Wheat cultivar Sids 4 had higher spike length and weight, grains weight per spike and 1000-grain weight. The cropping system 'CS1' had higher grain yield per fad ( 18.89 and 17.44 ardab ) than the other cropping systems in both seasons. The interaction between wheat cultivars and cropping systems significantly affected for all the studied wheat traits in both seasons. Wheat cultivar Misr 2 in cropping system CS1 recorded the highest grain yield (20.50 and 18.31) ardab per fad in both seasons. Meanwhile, the highest spike length and grains weight were obtained by growing wheat cultivar Sids 4 in cropping systems CS2, respectively, in the first season and with wheat cultivar Sids 12 in the second season. Relay intercropping cotton with wheat cultivar Sids 4 had higher seed cotton yield (8.80, 6.86 kintar) per fad than the other cultivars in both seasons. Cropping system CS1 had higher seed cotton yield ( 9.20, 7.14 kintar) per fad than other cropping systems in both seasons. The interaction between wheat cultivars and cropping systems significantly affected for all the studied cotton traits in both seasons hears rely intercropping cotton with wheat cultivar Sids 4 in intercropping CS1 give the highest values for all the studied cotton traits in both seasons. The intercropping had a significant effect on insects, larvae and whole insects. The intercropping resulted in a significant decrease in the number of insects in each of the Jassed, Aphin and the Nezara Viridula in all intercropping systems. Conversely, the intercropping cotton with wheat increased the number of red spider insects, thrips and white flies. In comparison, the intercropping resulted in a significant increase in the number of natural enemies in all intercropping systems in both seasons. while intercropping sesame with cotton also had a significant effect on insects in general, in contrast, this intercropping system had a significant effect on the incidence of almonds worms, where there was a significant decrease compared to single cotton in both seasons. on the above, intensive cropping system (Onion + wheat cultivar Sids 4/cotton + sesame) reduced insect incidence compared to the conventional cropping system (wheat/cotton). Relay intercropping cotton with wheat cultivar Sids 4 and intercropping sesame with cotton after wheat harvest (CS3) had the highest LER ( 2.81 and 2.64) , ATER(1.30 and 1.21) and MAI (LE 23985 and 21194) for the cropping system (Onion + wheat cultivar Sids 4/cotton + sesame)in the first and second seasons, respectively was higher values compared the other treatments in both seasons.

Štetne stenice vrežastih biljaka

Plants from the family Cucurbitaceae are attacked by many polyphagous pest insect species, as field and mole crickets, aphids, flea beetles and noctuids. Among mentioned pests, certain species of true bugs, order Hemiptera, can be found on vegetative and generative parts of the named plants. True bugs feed on all above ground plant parts sucking plant juices and causing damage to the fruits that can be in the form of deformation and/or occurrence of smaller or larger necrotic spots. These freckles are the result of nutrition ie. insertion of the stilets into the plant tissue, which affects the market value of the obtained fruits. Among the species most important for cucumber, watermelon, pumpkin and zucchini in our area, the most common are representatives of the family Miridae, genus Lygus sp. The most commonly encountered species are L. rugulipennis Popp. and L. pratensis L. Among the representatives of the family Pentatomidae, the most common are the Green Vegetable Stink Bug Nezara viridula L. and the Brown Marmorated Stink Bug Halyomorpha halys Stål, which feed mainly on cucumbers. Symptoms of damage from all true bugs species are similar, from small sting points, which are lighter at the beginning, to later necrotic spots, to the deformation of the fruits damaged during formation, to the smaller or larger necrotic spots seen on the mature fruits. Integrated approach in control of these pests should be applied, with good phytosanitary measures, weed control around the fields, and the like, although protection most often relies on the use of chemical insecticides. In our country, the list of registered pest control chemicals is not long. Beside that, true bugs cause most damage on ripening fruits, making the list of available insecticides even shorter.

Development of efficient RNAi in Nezara viridula for use in insecticide target discovery.

Stink bugs are an emerging pest in many regions of the world but their molecular biology is still poorly understood. While several transcriptomes are available, the lack of validated gene manipulation tools like RNA interference (RNAi) in species such as the southern green stinkbug Nezara viridula precludes the characterization of individual genes in vivo. Such tools are particularly useful in performing high-throughput screens to search for essential genes that can be prioritized as potential insecticide targets. Here, we developed and optimized an efficient RNAi in N. viridula for use in insecticide target discovery and beyond. The visible marker Sex combs reduced and the essential gene Actin were used to verify the usability and efficiency of RNAi by microinjection at both the adult and nymphal stages, respectively, with nymphal approach presenting significant advantages. Following validation, RNAi was then used to measure lethality following the knockdown (KD) of two genes that are known insecticide targets, Chitin synthase, and Acetyl-CoA carboxylase. The KD of each gene resulted in >75% corrected mortality. These results indicate that RNAi is an effective tool in N. viridula and set a benchmark to evaluate potential targets in future RNAi screens aimed at insecticide target discovery.

Natal origin of the invasive biosecurity pest, brown marmorated stink bug (Halyomorpha halys: Penatomidae), determined by dual-element stable isotope-ratio mass spectrometry.

BACKGROUNDPost‐border detection of a single brown marmorated stink bug (BMSB) in New Zealand warranted a biosecurity response, the nature of which would be influenced by its status as part of an established population or as a new arrival. Stable isotope analysis has the potential to determine natal origins, but is difficult to achieve for samples as small as a single insect. Here an analytical modification to measure small samples was successfully trialled as a means to supply evidence as to the local or exotic natal origin of the intercepted BMSB specimen.RESULTSSufficient analytical sensitivity was achieved using a modified isotope ratio mass spectrometry method, involving thermolysis and carbon monoxide cryofocusing, to enable the simultaneous analysis of δ2H and δ18O from wings of the post‐border BMSB sample. The values were much lower than those of the New Zealand green vegetable bug, used as a local reference. However, they fell within the range of those for BMSB of Northern Hemisphere origin intercepted at the New Zealand border over the same time period, specifically overlapping with the USA and Italy, but not China.CONCLUSIONThe isotope signature of the post‐border detected BMSB suggested a significantly cooler climate than the North Island of New Zealand, indicating that it was a new arrival and did not represent an established population. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Transmission of Eremothecium coryli (syn. Nematospora coryli) to Consecutive Cotton Bolls by Individual Stink Bugs1

Cotton (Gossypium hirsutum L.) is a high-value cash crop persistently plagued by insect pests such as stink bugs and related species. Stink bugs vector pathogens that cause necrosis of cotton seed and lint, yet the frequency of pathogen transmission into successive bolls by individual stink bugs is not documented. Individual adults of southern green stink bug, Nezara viridula (L.), (n = 80) were provided green beans (Phaseolus vulgaris L.) infected with the fungus Eremothecium coryli (Peglion) Kurtzman (syn. Nematospora coryli Peglion) and caged sequentially with five bolls of known age to determine potential for infection of consecutive bolls by a single stink bug. Stink bug adults fed on 82.4% of bolls (n = 108), and the pathogen was transmitted to 68.5% of these bolls (n = 89). As expected, insect bacterial flora was detected in all bolls with evidence of insect feeding. Overall, frequency of feeding ranged from one to five bolls per stink bug; frequency of boll infection also ranged from one to five bolls per stink bug. The frequency of infection by E. coryli in bolls did not differ between sexes of stink bugs (Fisher's Exact Test: P = 0.84), and the number of females and males infecting one to five bolls did not differ (Fisher's Exact Test: P = 0.92). The findings can serve as an impetus for determining whether current insect management thresholds should be reconsidered given the potential for infection of multiple bolls by individual southern green stink bugs.