Stink Bug Densities Research Articles

Euschistus heros: Economic injury level and economic threshold of early maturing carioca common bean cultivar

Early maturing common-bean cultivars lack information referring to Euschistus heros (Fabricius, 1798) (Hemiptera: Pentatomidae) feeding damage assessment. This information is pertinent towards establishing economic threshold for an integrated pest management program. The aim of this study was to analyze the relationship, between the density of stink bugs and the degree of injuries towards the pod and grain production, quantity and quality, of the IPR Curió cultivar. The experiments were conducted during two seasons at the IDR-Paraná in Londrina, Paraná, in field conditions. The experimental design was randomized blocks with five repetitions. The treatments were: 0 (control); 1; 2; 3; 4; 5 E. heros m-1. The evaluated variables were number of grained and flat pods; healthy, damaged and aborted grain mass; grain yield. The economic injury level (EIL), economic threshold (ET) and spraying efficiency influence on the ET were calculated. The total number of grained pods was not affected. More than three brown stink bugs, during the summer season, significantly increases flat pod output. The rainy season resulted in greater aborted grains. Increasing E. heros densities, during the summer season, significantly reduces the healthy grain output. The damaged grain mass doubles at higher than one E. heros population densities. The total grain mass produced was not affected. During the summer season, each E. heros reduces 11% of healthy grain output, and during the rainy season 6%. During the summer season was 1.50 of E. heros m-1 and for the rainy season 1.00 E. heros m-1. The spraying efficiency should directly affect the EIL, modifying the value, thus better resembling the field conditions.

Competition between brown stink bug (Hemiptera: Pentatomidae) and corn earworm (Lepidoptera: Noctuidae) in field corn.

Interspecific competition is an important ecological concept which can play a major role in insect population dynamics. In the southeastern United States, a complex of stink bugs (Hemiptera: Pentatomidae), primarily the brown stink bug, Euschistus servus (Say), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), are the 2 most common pests of field corn, Zea mays L. (Poales: Poaceae). Stink bugs have the greatest potential for economic injury during the late stages of vegetative corn development when feeding can result in deformed or "banana-shaped" ears and reduced grain yield. Corn earworm moths lay eggs on corn silks during the first stages of reproductive development. A 2-year field study was conducted to determine the impact of feeding by the brown stink bug during late-vegetative stages on subsequent corn earworm oviposition, larval infestations, and grain yield. Brown stink bug feeding prior to tasseling caused deformed ears and reduced overall grain yield by up to 92%. Across all trials, varying levels of brown stink bug density and injury reduced the number of corn earworm larvae by 29-100% and larval feeding by 46-85%. Averaged across brown stink bug densities, later planted corn experienced a 9-fold increase in number of corn earworm larvae. This is the first study demonstrating a competitive interaction between these major pests in a field corn setting, and these results have potential implications for insect resistance management.

Using stink bug migration behavior for physical exclusion.

Stink bugs have become an increasing concern for tree fruit growers due to changing management strategies and the introduction of an invasive species. The use of broad-spectrum insecticides for stink bug control disrupts biological control and leads to secondary pest outbreaks. To seek alternative tactics, we investigated the physical exclusion of native stink bugs with single-wall net barriers at orchard borders. First, stink bug capture on clear sticky panels along orchard edges showed that movement between the native shrub-steppe vegetation and the orchard occurs for much of the growing season instead of the presumed single migration event in August. Most stink bugs were captured between 1 m and 3 m heights, signifying a 4 m exclusion barrier would intercept migrating bugs. We tested large net barriers (4 m × 23 m) constructed of plain netting with or without deltamethrin-infused netting in flaps compared to a no-net control. The capture of target and nontarget arthropods was determined with plastic tarps below the nets or on the open ground of the control. Net barriers did not directly affect stink bug densities in the orchards, although orchard populations were low overall. Barriers did intercept stink bugs, and the addition of deltamethrin flaps enhanced stink bug mortality but at the price of nontarget arthropod mortality. Our results indicate that stink bug management efforts should focus earlier in the growing season and given the long period of migration, barriers are a more sustainable way of slowing movement into the orchard than the current sole reliance on chemical control.

Hierarchical forecasting models of stink bug population dynamics for pest management

In recent decades, the intensification of agricultural production, accompanied by an increasing pressure from pests in various crops, has resulted in a substantial increase in the use of synthetic pesticides. Integrated pest management (IPM) provides a framework for the development and use of sustainable control strategies, which include the monitoring of the crop pest complex and the use of decision tools such as predictive models. In this study, an empirical modeling approach based on a hierarchical Bayesian model with a state-space structure was developed to perform stink bug (Pentatomidae) density forecasts to assist in deciding when to carry out pest control interventions, thus increasing the efficacy and efficiency of IPM. Using stink bug abundance and crop phenology data, along with meteorological data from eight different sites in Argentina, we made 1-week forecasts of population density, evaluated the predictive capacity of different models using Leave-One-Out-Cross-Validation, and analyzed how the uncertainty in the predictions vary as a function of the number of vertical beat sheet samples. The forecasts made with our best model showed a reasonable degree of accuracy. We found that i) the observation error of the vertical beat sheet method was much larger than expected, and ii) the uncertainty analysis suggested a sample size of 40 to obtain a good balance between precision and sampling effort, which is in stark contrast to the average sample size usually taken by advisors. Our approach provides advisors with a tool to make better-informed decisions about when and if to carry out pest control interventions.

Brown Stink Bug (Hemiptera: Pentatomidae) Damage to Seedling Corn and Impact on Grain Yield.

Brown stink bugs, Euschistus servus, are an important early-season pest of field corn in the southeastern United States. Feeding in the early stages of corn development can lead to a number of growth deformities and deficiencies and, ultimately, a reduction in yield. An observational and two experimentally manipulated trials were conducted in 2017 and 2018 to 1) determine optimal timing for assessing brown stink bug damage, 2) assess the level of damage from which yield compensation can occur, and 3) examine the relationship between brown stink bug density and early-season damage and yield. Fields were identified with infestations of brown stink bugs and a damage rating system for early stages of corn was established. Varying rates of brown stink bug densities were introduced using field cages and damage was assessed throughout the season. The density and duration of stink bug infestations were critical factors for damage potential, with each day of active feeding per plant resulting in a loss of ~14 kg/ha in yield. The level of damage in early stages of corn was categorized into easily identifiable groups, with only the most severe damage leading to a reduction in yield. Moderate and minimal feeding damage did not result in yield loss. This study emphasizes the need for early and frequent scouting of corn to determine the risk of damage and yield loss from brown stink bugs. Results from this study can be used to help develop management programs for brown stink bugs in the early vegetative stages of field corn.

Biology and Management of the Rice Stink Bug (Hemiptera: Pentatomidae) in Rice, Oryza sativa (Poales: Poaceae)

Abstract The rice stink bug, Oebalus pugnax (Fabricius), is the most important late-season insect pest of rice in the southern United States. Nymphs and adults feed on rice grains, resulting in losses in yield and grain quality. Aspects of the biology, ecology, life history, and chemical ecology have been investigated in southern rice producing states but several outstanding questions remain. Standard economic threshold levels (ETLs) based on sweep net sampling for rice stink bug have been established depending on grain development stage and geographic location. However, recent studies on the relationship between rice stink bug densities, feeding damage, and its economic impacts suggests that changes to ETLs for rice stink bug may be needed. The primary management tactic for controlling rice stink bug infestations is the application of chemical insecticides, but alternative management tactics are needed because of the potential for development of insecticide resistance and impacts on non-target organisms. Biological control appears to be a promising strategy, even though it has remained largely untapped. Future research should focus on the biology, behavior, host plant preference, and chemical ecology of the rice stink bug, knowledge of which will aid in the development of integrated pest management strategies. This review article covers the biology, feeding behavior, sampling techniques, ETLs, management, knowledge gaps, and potential management tactics of rice stink bug.

Photoperiod-Specific Within-Plant Distribution of the Green Stink Bug (Hemiptera: Pentatomidae) on Cotton

Sampling methods for detecting stink bugs are intensive, time-consuming, and yield variable results. In a 2-yr mark-release-observe experiment, over 500 adult green stink bugs, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), were used to test for variation in nocturnal and diurnal insect distribution patterns on cotton. Field-collected stink bugs were marked or unmarked with nontoxic fluorescent sharpie markers, released, and monitored in cotton fields at peak bloom. Stink bugs were monitored visually during day and night, aided by a handheld blacklight for nighttime observations. Within-cotton distribution insect observations were categorized by plant section (i.e., bottom, middle, and top branches), by fruiting positions and leaf surface, and by concealed or exposed orientation on floral bracts and leaf surfaces. Green stink bugs were primarily distributed on the middle and top branches irrespective of photoperiod, and on bolls in first position from the main stem. Differences in stink bugs observed concealed or exposed on fruiting structures were detected. During daytime, stink bugs were primarily observed inside the bract of bolls, and when detected on leaves concealed on the lower surface. In contrast, stink bugs were primarily outside the bract of bolls at night, and when detected on leaves were exposed on an upper surface. These results support focus on assessing internal boll injury for evaluating stink bug injury to avoid the challenges in stink bug detection observed here, and point to additional study to refine stink bug density estimation when needed.

Spatial Patterns and Sequential Sampling Plans for Estimating Densities of Stink Bugs (Hemiptera: Pentatomidae) in Soybean in the North Central Region of the United States.

Stink bugs are an emerging threat to soybean (Fabales: Fabaceae) in the North Central Region of the United States. Consequently, region-specific scouting recommendations for stink bugs are needed. The aim of this study was to characterize the spatial pattern and to develop sampling plans to estimate stink bug population density in soybean fields. In 2016 and 2017, 125 fields distributed across nine states were sampled using sweep nets. Regression analyses were used to determine the effects of stink bug species [Chinavia hilaris (Say) (Hemiptera: Pentatomidae) and Euschistus spp. (Hemiptera: Pentatomidae)], life stages (nymphs and adults), and field locations (edge and interior) on spatial pattern as represented by variance-mean relationships. Results showed that stink bugs were aggregated. Sequential sampling plans were developed for each combination of species, life stage, and location and for all the data combined. Results for required sample size showed that an average of 40-42 sample units (sets of 25 sweeps) would be necessary to achieve a precision of 0.25 for stink bug densities commonly encountered across the region. However, based on the observed geographic gradient of stink bug densities, more practical sample sizes (5-10 sample units) may be sufficient in states in the southeastern part of the region, whereas impractical sample sizes (>100 sample units) may be required in the northwestern part of the region. Our findings provide research-based sampling recommendations for estimating densities of these emerging pests in soybean.

Density and Egg Parasitism of Stink Bugs (Hemiptera: Pentatomidae) in Mimosa

Stink bugs (Hemiptera: Pentatomidae) are primary pests in most fruit, vegetable, grain, and row crops worldwide. The polyphagous habits of these pest species compels them to forage within and between closely associated non-crop and crop habitats across farmscapes in response to changing food resources. The exotic mimosa tree, Albizia julibrissin Durazz (Fabaceae), commonly grows in thickets along roadsides and in woodlands adjacent to agricultural crops across the southeastern USA. Thus, the objective of this study was to determine if mimosa was a host plant of stink bugs in southwest Georgia. Chinavia hilaris (Say) (Hemiptera: Pentatomidae) fed and developed on mimosa during early Jul through mid-Aug. Nymphs and adults of C. hilaris fed more frequently on fruit than on leaves of mimosa. Other stink bugs viz., Euschistus servus (Say), E. tristigmus (Say), E. obscurus (Palisot), Nezara viridula (L.), Thyanta custator custator (F.), and Loxa flavicollis (Drury) (all Hemiptera: Pentatomidae), also were detected on mimosa, but only as adults feeding on fruit. Trissolcus edessae Fouts (Hymenoptera: Scelionidae) was the most prevalent parasitoid of C. hilaris eggs on mimosa, but Anastatus reduvii (Howard) (Hymenoptera: Eupelmidae) also emerged from eggs of this stink bug. Overall, 46.6% of the C. hilaris eggs found on mimosa were parasitized. In conclusion, C. hilaris is the primary stink bug species developing on mimosa in southwest Georgia, serving as a potential source of this stink bug into nearby crops.

Influence of Weed Manipulation in Field Borders on Brown Stink Bug (Hemiptera: Pentatomidae) Densities and Damage in Field Corn.

Brown stink bug, Euschistus servus (Say), is a damaging pest of corn, Zea mays L. (Cyperales: Poaceae), in the southeastern United States. In North Carolina, during the spring, winter-planted wheat, Triticum aestivum L. (Cyperales: Poaceae), serves as the earliest available crop host, and E. servus seems to prefer this crop over seedling corn. In the absence of wheat in the agroecosystem, weeds serve as a bridge host for a portion of overwintered E. servus populations until they move to corn and other subsequent crops. Our objective was to reduce densities of E. servus in corn by manipulating the weedy field borders with mowing and applications of dicamba herbicide. During the study, multiple species of stink bugs (n =16) were found associated with weed plots. However, E. servus was the predominant (>94%) stink bug species in the corn. In this farmscape, density of E. servus adults in the unmanaged weed plots began declining around the second week of May, followed by an increase in density in adjacent corn plots. This movement coincided with the seedling growth of corn. In 2016, applications of dicamba in the weedy field border resulted in a lower density of E. servus in herbicide-treated weed plots compared with untreated plots. Despite this difference, manipulations of weeds did not lead to any significant changes in density of E. servus adults in corn. Further evidence suggested that a prominent external source of E. servus, other than field-bordering weeds, in the farmscape was likely driving densities in corn.

Influence of Pheromone-Baited Traps on Stink Bugs in Cotton.

Stink bugs (Hemiptera: Pentatomidae) are economic pests in fruit, vegetable, grain, and row crops worldwide. Pyramid traps baited with lures of stink bug aggregation pheromones capture these pests in the field, but stink bugs can congregate on plants near traps. Our specific objective was to examine the area of arrestment of stink bugs based on their density on cotton at different distances from pheromone-baited traps. We used lures of the aggregation pheromone of Euschistus spp., methyl (2E,4Z)-2,4-decadienoate (MDD), and Plautia stali Scott, methyl [2E,4E,6Z]-2,4,6-decatrienoate (MDT). Overall, Euschistus servus (Say), Euschistus tristigmus (Say), Chinavia hilaris (Say), and Nezara viridula (L.) were the main stink bug species on cotton. Over the 3-yr study, adult stink bug density was significantly higher on the row of cotton immediately adjacent to a pheromone-baited trap than on the second and third row from the trap. Stink bug density was significantly lower on the seventh cotton row beyond the trap in 2015, on the fourth, eighth, and 16th rows in 2017, and on the fourth and eighth rows in 2018 compared to the two or three rows nearest the trap. These results indicate that adult stink bugs congregated mainly on the three cotton rows (2.73 m in width) nearest a trap. Management strategies utilizing pheromone-baited traps for stink bug control, such as trap cropping in combination with traps, should take into consideration this area of arrestment.

Management of the Stink Bugs Dolycoris baccarum (L.) and Piezodorus lituratus (F.) (Hemiptera: Pentatomidae), and Chalky Spot Damage on Red Lentil in Southeast Anatolia Region, Turkey

Chalky spot damage caused by the stink bugs Dolycoris baccarum (L.) and Piezodorus lituratus (F.) (Hemiptera: Pentatomidae) is a serious problem for red lentil production in Southeast Anatolia, Turkey. This study aimed to determine spraying time against stink bugs, based on lentil developmental stages and evaluate potential agronomic methods (early vs. timely harvest and traditional harvest with sickle bar mower vs. combine harvester) to reduce chalky spot. Field trials were carried out during 2011–2012 in three provinces of Southeast Anatolia (Diyarbakir, Mardin and Sanliurfa).Chalky spot damage was initiated at the R6 stage (full seed, seed on nodes 10-13 fill the pod cavities) when the stink bug nymphs started to be observed and the plant had soft immature seeds that were more susceptible to feeding by stink bugs. In early harvested lentil fields, the percentage of chalky spot damage was 0.60 and 0.20 in Diyarbakir and Sanliurfa provinces, respectively. It was lower than that of timely harvest. On the other hand, damaged seed percentage significantly reduced by changing the harvesting from traditional to combine harvesting and damage ratio was 0.90 and 0.00 in Diyarbakir and Mardin provinces, respectively. We conclude that the management to protect lentil crops from stink bug infestations should be initiated at the R6 growth stage, and that crops should be harvested a week earlier using combine harvester to reduce stink bug density and chalky spot damage.

Evaluating a polyculture trap crop for organic management of Halyomorpha halys and native stink bugs in peppers

Organic farming systems are significantly challenged by the invasive Halyomorpha halys (Stal) and native stink bug species that injure vegetable crops. This two-year study evaluated a polyculture trap crop composed of sunflower and sorghum for organic pepper production at 11 sites in 8 mid-Atlantic and Southeastern states. Stink bug densities in the trap crop and peppers were recorded weekly (mid-June through September), and stink bug fruit injury was compared for trap crop-protected and unprotected control peppers. The trap crop was highly attractive, harboring 5–50× more stink bugs per m2 than the peppers and providing an 8-week attraction period coinciding with peak stink bug activity. Despite this attractiveness, the trap crop was not effective at diverting adult stink bugs away from the pepper crop during the early fruiting period at most sites. However, the average density of stink bug nymphs in pepper plots surrounded by trap crops was 4× lower than controls 5 weeks after planting for pooled sites. Trap crop-protected peppers also had significantly less injury compared to control peppers pooled across sites and years. However, the resulting reduction in pepper damage was insufficient to be economically viable. Overall, results provide evidence that a polyculture trap crop was most effective during the latter weeks of the pepper crop cycle. Future research should address spatial arrangement of the trap crop or integration of complimentary management tactics within the trap crop earlier in the growing season to target the initial colonizing adult stink bugs.

Tratamento de sementes para manejo do percevejo-barriga-verde na cultura de soja e milho em sucessão

Resumo: O objetivo deste trabalho foi avaliar o efeito do tratamento de sementes com inseticidas sobre o manejo de Dichelops melacanthus e a produtividade da soja e do milho, cultivados em sucessão. O estudo foi realizado em campo, nas safras 2012/2013 (I) e 2013/2014 (II). Avaliaram-se os inseticidas imidacloprido, tiametoxam, tiodicarbe, fipronil e abamectina. Determinaram-se: a densidade populacional do percevejo, a produtividade de soja e milho, e a intensidade da injúria em milho. A densidade do percevejo permaneceu abaixo de um inseto por metro quadrado, na maior parte do ciclo da soja. Os picos populacionais foram observados nas primeiras semanas, após a emergência do milho, e atingiram 2,2 (safra I) e 6,7 (safra II) percevejos por metro quadrado. Na cultura da soja, os inseticidas não reduziram a densidade populacional do percevejo. Na cultura do milho, o imidacloprido reduziu a densidade do percevejo em 23,2% (safra I) e 38,8% (safra II), e a injúria em 61,8% (safra I) e 26,4% (safra II). O tiametoxam reduziu a densidade dos insetos em 27,8% (safra II) e a injúria em 42,7% (safra I). O tratamento de sementes com inseticidas não proporciona aumento de produtividade à soja e ao milho, portanto, não se justifica sua utilização nas condições deste estudo.

Density and Egg Parasitism of Stink Bugs (Hemiptera: Pentatomidae) in Elderberry and Dispersal Into Crops.

Chinavia hilaris (Say), Euschistus servus (Say), Euschistus tristigmus (Say), and Thyanta custator custator (F.) (Hemiptera: Pentatomidae) are serious pests of crops in the southeastern United States but little is known concerning their dispersal from noncrop hosts in woodlands into crops. This 2-yr study was conducted to investigate whether elderberry [Sambucus nigra subsp. canadensis (L.) R. Bolli] in woodlands serves as a source of stink bugs dispersing into adjacent crops and to examine parasitism of C. hilaris and E. servus eggs on this plant. Elderberry was a reproductive host for each of the four stink bug species; females oviposited on plants with subsequent nymphs feeding on elderberry and developing into adults. Anastatus mirabilis (Walsh & Riley) (Hymenoptera: Eupelmidae), Anastatus reduvii (Howard), and Trissolcus edessae Fouts (Hymenoptera: Scelionidae) were prevalent egg parasitoids of C. hilaris but A. reduvii was the prevalent parasitoid of E. servus. Newly developed stink bug adults were first detected on elderberry around mid-July. Then in late July and early August, as elderberry fruit senesced and cotton bolls became available, stink bugs began dispersing from elderberry into cotton based on recapture of stink bugs on cotton that had previously been marked on elderberry. In addition, in 2015, density of C. hilaris, E. servus, and E. tristigmus was higher in cotton with elderberry than in cotton without it. Over the study, economic threshold was reached for four of seven cotton fields. Elimination of elderberry in woodlands adjacent to cotton may be a viable management tactic for control of stink bugs in cotton.

Trap Cropping Systems and a Physical Barrier for Suppression of Stink Bugs (Hemiptera: Pentatomidae) in Cotton.

Euschistus servus (Say), Nezara viridula (L.), and Chinavia hilaris (Say) (Hemiptera: Pentatomidae) are economic pests of cotton in the coastal plain of the southeastern United States. The objective of this 2-yr study was to determine the ability of trap cropping systems, pheromone-baited stink bug traps, and a synthetic physical barrier at the peanut-to-cotton interface to manage stink bugs in cotton. The physical barrier was the most effective management tactic. Stink bug density in cotton was lowest for this treatment. In 2010, boll injury was lower for the physical barrier compared to the other treatments except for soybean with stink bug traps. In 2011, boll injury was lower for this treatment compared to the control. Soybean was an effective trap crop, reducing both stink bug density in cotton and boll injury regardless if used alone or in combination with either stink bug traps or buckwheat. Incorporation of buckwheat in soybean enhanced parasitism of E. servus egg masses by Telenomus podisi Ashmead in cotton. The insertion of eyelets in the lid of the insect-collecting device of a stink bug trap allowed adult stink bug parasitoids, but not E. servus, to escape. Stand-alone stink bug traps were not very effective in deterring colonization of cotton by stink bugs or reducing boll injury. The paucity of effective alternative control measures available for stink bug management justifies further full-scale evaluations into these management tactics for control of these pests in crops.

Spatiotemporal Dynamics of the Invasive Halyomorpha halys (Hemiptera: Pentatomidae) in and Between Adjacent Corn and Soybean Fields.

Knowledge on movement and spatial patterns of insect pest populations among preferred hosts aids in the development of effective pest management strategies. In this study, we quantified the spatiotemporal dynamics of the invasive brown marmorated stink bug, Halyomorpha halys (Stål 1855), in relation to field corn, Zea mays L., and soybean, Glycine max (L.), crop phenology. We also examined the potential role of corn as a source of stink bugs in adjacent soybean. The highest density of stink bugs in each crop coincided with blister to milk-dough stages in corn (R2-R3/R4), and beginning seed to full seed (R5-R6) stages in soybean. In entire fields of adjacent corn and soybean, H. halys was found in very low density (<0.5/m(2)) or absent beyond 25 m from the field edge. Inverse distance weighted interpolations of H. halys densities suggest potential dispersal of H. halys, particularly adults and large nymphs, from corn into soybean, coinciding with the end of dough stage in corn and beginning of soybean seed development stage. These findings have important implications for managing H. halys through location and timing of scouting efforts, consideration of crop arrangement, and decisions on management interventions. Repeated scouting of field corn to assess H. halys densities, particularly from blister stage onwards, could inform decisions on management interventions for preventing or mitigating H. halys colonization into soybean. Where H. halys is an economic problem, reducing the extent of boundary shared between corn and soybean could reduce dispersal into soybean.

Spatial and temporal dynamics of stink bugs in southeastern farmscapes.

A 3-yr study (2009–2011) was conducted to examine the spatial and temporal dynamics of stink bugs in three commercial farmscapes. Study locations were replicated in South Carolina and Georgia, in an agriculturally diverse region known as the southeastern coastal plain. Crops included wheat, Triticum aestivum (L.), corn, Zea mays (L.), soybean, Glycine max (L.), cotton, Gossypium hirsutum (L.), and peanut, Arachis hypogaea (L.). Farmscapes were sampled weekly using whole-plant examinations for corn, with all other crops sampled using sweep nets. The predominant pest species of phytophagous stink bugs were the brown stink bug, Euschistus servus (Say), the green stink bug, Chinavia hilaris (Say), and the southern green stink bug, Nezara viridula (L.). Chi-square tests indicated a departure from a normal distribution in 77% of analyses of the variance to mean ratio, with 37% of slopes of Taylor’s power law and 30% of coefficient β of Iwao’s patchiness regression significantly greater than one, indicating aggregated distributions. Spatial Analyses by Distance IndicEs (SADIE) indicated aggregated patterns of stink bugs in 18% of year-end totals and 42% of weekly counts, with 80% of adults and nymphs positively associated using the SADIE association tool. Maximum stink bug densities in each crop occurred when the plants were producing fruit. Stink bugs exhibited greater densities in crops adjacent to soybean in Barnwell and Lee Counties compared with crops adjacent to corn or fallow areas. The diversity of crops and relatively small size of fields in the Southeast leads to colonization of patches within a farmscape. The ecological and management implications of the spatial and temporal distribution of stink bugs within farmscapes are discussed.

Assessment of a more conservative stink bug economic threshold for managing stink bugs in Brazilian soybean production

The objective of this study was to assess the stink bug economic threshold for soybean integrated pest management decisions. For this purpose, a replicated experiment was implement in a commercial soybean crop located in Arapongas, Parana State, Brazil, during two crop seasons: 2010/2011 and 2011/12. Treatments consisted of different stink bug densities triggering the application of insecticides, ¼ of the economic threshold (ET) (= 0.5 stink bugs m−1) and ET (= 2 stink bugs m−1), and without applying an insecticide (control). The stink bugs were quantified weekly and all specimens were identified to the species level. At harvest, yield and quality of the seeds were also measured. In all crops, Euschistus heros was the most abundant species. The highest yield and percentage of viable seeds were found in the 'BMX Power RR′ cultivar (indeterminate growth cultivar), indicating a better seed quality. At the end of the experiment, there was no observed difference in yield between different stink bug management thresholds, indicating the effectiveness of the control when adopting ET. This study demonstrates that decreasing the economic threshold increased the number of required insecticide applications, but did not increase yield or bean quality neither the net income when an economic analysis was performed.

Adjacent habitat influence on stink bug (Hemiptera: Pentatomidae) densities and the associated damage at field corn and soybean edges.

The local dispersal of polyphagous, mobile insects within agricultural systems impacts pest management. In the mid-Atlantic region of the United States, stink bugs, especially the invasive Halyomorpha halys (Stål 1855), contribute to economic losses across a range of cropping systems. Here, we characterized the density of stink bugs along the field edges of field corn and soybean at different study sites. Specifically, we examined the influence of adjacent managed and natural habitats on the density of stink bugs in corn and soybean fields at different distances along transects from the field edge. We also quantified damage to corn grain, and to soybean pods and seeds, and measured yield in relation to the observed stink bug densities at different distances from field edge. Highest density of stink bugs was limited to the edge of both corn and soybean fields. Fields adjacent to wooded, crop and building habitats harbored higher densities of stink bugs than those adjacent to open habitats. Damage to corn kernels and to soybean pods and seeds increased with stink bug density in plots and was highest at the field edges. Stink bug density was also negatively associated with yield per plant in soybean. The spatial pattern of stink bugs in both corn and soybeans, with significant edge effects, suggests the use of pest management strategies for crop placement in the landscape, as well as spatially targeted pest suppression within fields.