Dichelops Furcatus Research Articles

The stink bug Dichelops furcatus: a new pest of corn that emerges from soybean stubble.

Over the last decades, Argentine and Brazilian farmers have adopted no-tillage cultivation systems and multiple cropping, which have decreased the abundance of traditional pests, such as Nezara viridula, and favored the development of some stink bugs of secondary importance, like Dichelops furcatus, D. melacanthus and Euschistus heros. No-till farming leaves the soil undisturbed, to mitigate erosion, and sufficient crop residue on the field, which is used by D. furcatus as a shelter under unfavorable conditions, and as a shelter against insecticides. Moreover, implementing multiple cropping systems increases crop rotation from soybean to corn, and places overwintering adults of D. furcatus in contact with corn seedlings in spring. Attacks of this stink bug species produce deformation and abortion of corn seedlings, resulting in up to 50% corn yield reduction. The increasing abundance of D. furcatus intensifies the damage on developing pods and seeds of soybean, becoming a primary pest of soybean, and a new pest of corn. Here we summarize the current knowledge about D. furcatus, its biology, life cycle, and geographical distribution pattern in South America. Additionally, we describe the general causes and consequences of D. furcatus as a new pest of corn that emerges from crop stubble. Then, we provide an overview of the chemical control, natural enemies, and possible agronomical practices to improve sustainable crop production methods to control this pest. © 2022 Society of Chemical Industry.

Plant volatiles guide the new pest Dichelops furcatus to feed on corn seedlings.

Recently, in temperate and neotropical regions of South America the generalist stink bug Dichelops furcatus (Hemiptera: Pentatomidae) became a new pest of corn (Zea mays) seedlings. Implementation of no-tillage cultivation system left organic matter covering the soil, which shelters adults of stink bugs during winter. In spring, corn is sowed under soybean stubble and D. furcatus adults start to feed on seedlings. To determine corn-derived volatile organic compounds (VOCs) that attract this stink bug species, we evaluated stink bug preferences from two corn hybrids with contrast germplasm backgrounds, a temperate and a tropical hybrid. Stink bugs preferred to feed on temperate seedlings rather than on the tropical ones. GC-MS and PCA analysis of VOCs suggested that hybrids emitted contrasting blends. Linalool represented 68% of total VOCs emitted from temperate corn, while in the tropical hybrid this compound represented 48%. Olfactometer experiments demonstrated that linalool was attractive to stink bugs. However, 2 h of D. furcatus attack induced emission of 14 additional VOCs in temperate seedlings, and olfactometer bioassay and blend of VOCs emission suggested that perceived volatiles by stink bugs induced feeding avoidance. The increment of VOCs emission was associated with the induction of JA, JA-Ile, ABA, and IAA, and decreasing of SA concentrations. This is the first time showing a complete profile of defensive phytohormones induced by stink bugs feeding on corn, and further demonstrating that a blend of corn seedling-associated VOCs, mainly composed by linalool, modulates D. furcatus adults' behavior and feeding preferences. © 2021 Society of Chemical Industry.

Virulence of Metarhizium brunneum (Ascomycota: Hypocreales) Strains Against Stinkbugs Euschistus heros and Dichelops furcatus (Hemiptera: Pentatomidae).

Three strains of fungi belonging to the genus Metarhizium Sorokīn (ARSEF 4556, ARSEF 3297, native strain) were assayed against adults and nymphs of the Neotropical brown stinkbug Euschistus heros (F.) and the green-belly stinkbug Dichelops furcatus (F.). The most virulent strain, ARSEF 4556, caused over 90% mortality. The average survival time of the second and fifth instar nymphs and adults following immersion in 1 × 108 conidia ml-1 was 4.8, 5.7, and 5.2 d, respectively. The second instar nymphs were more susceptible than the adults. The LC50 values and median survival times for second instar and adult E. heros were 1.6 × 107 and 3.1 × 107 conidia ml-1 and 6 and 8 d, respectively. Eggs of E. heros and the closely related stinkbug, D. furcatus, were highly susceptible to ARSEF 4556 with the mean mortality of eggs immersed in 1 × 108 conidia ml-1 being 77.4% and 89.7%, respectively. The strain 3297 showed also good aptitudes for stinkbugs control with mortalities higher than 80% against nymphs and adults and eggs mortalities of 75.5% for E. heros and 79.6% for D. furcatus. This study has shown that it is possible to have a two-pronged control strategy, targeting adults and to reduce oviposition and targeting egg clusters to prevent emergence and dispersal of nymphs. Besides early instars of nymphs have been shown to be more susceptible to the fungal strains than late instars and adults.

Susceptibility of Euschistus heros and Dichelops furcatus (Hemiptera: Pentatomidae) to insecticides determined from topical bioassays and diagnostic doses for resistance monitoring of E. heros in Brazil

The Neotropical brown stink bug, Euschistus heros (F.), and the green belly stink bug, Dichelops furcatus (F.) (Hemiptera: Pentatomidae), are the main sucking pests of soybean and maize in Brazil. Here, we characterized the susceptibility of populations of E. heros and D. furcatus to insecticides and define doses for resistance monitoring of E. heros. Stink bug populations collected in the seasons from 2018 to 2020 were exposed to technical grade insecticides in topical bioassays. Populations of E. heros presented low variation in the susceptibility to acephate (LD50 = 0.22–0.69 μg a.i./stink bug), thiamethoxam (LD50 = 0.0039–0.032 μg a.i./stink bug) and bifenthrin (LD50 = 0.021–0.10 μg a.i./stink bug), with resistance ratios < 8.2-fold in relation to a susceptible population. However, the same populations showed high variation in the susceptibility to lambda-cyhalothrin (LD50 = 0.023–0.35 μg a.i./stink bug) with resistance ratios from 3.1- to 15.7-fold. Populations of D. furcatus had a similar susceptibility to acephate (LD50 = 0.30–0.53 μg a.i./stink bug), thiamethoxam (LD50 = 0.070–0.14 μg a.i./stink bug) and lambda-cyhalothrin (LD50 = 0.27–0.56 μg a.i./stink bug), with resistance ratios < 2.1-fold. The diagnostic doses of 1.30 (acephate), 0.34 (thiamethoxam), 0.36 (bifenthrin) and 1.73 (lambda-cyhalothrin) μg a.i./stink bug were defined for monitoring the susceptibility of E. heros. In these doses, mortalities of E. heros populations ranged from 55.3% to 100%. Our findings indicate that E. heros presents a lower inter-population variation in susceptibility to acephate, bifenthrin and thiamethoxam than lambda-cyhalothrin, while D. furcatus had similar susceptibility to the insecticides tested. The diagnostic doses defined here will be used in further resistance monitoring programs.

Electropenetrographic Comparison of Feeding Behavior of Dichelops furcatus (Hemiptera: Heteroptera: Pentatomidae) on Soybean and Spring Cereals

We used electropenetrography to quantify and compare counts and durations of selected waveforms, produced by adult females of the stink bug Dichelops furcatus (F.). Insects fed on immature soybean pods and immature seed heads of four spring cereals: wheat, black oat, barley, and rye. On all foods, bugs spent over 60% of their plant access time in non-probing activities. This total waveform duration was significantly longer on barley and rye compared to those on soybean and oat; wheat was intermediate. Considering only probing activities, bugs spent longer durations (ca. 2×), on soybean and oat compared to barley, rye, and wheat plants. Bugs produced significantly more pathway events on soybean and rye than on wheat and barley; with a significantly shorter duration per event on rye. The counts and durations of xylem ingestion did not differ among foods. Cell rupturing activities on seeds were longer on soybean (ca. 23%) and oat (ca. 21%), than on barley and rye (ca. 6%). The durations of ingestion events on seeds were significantly shorter on soybean (over 3×) compared to those on barley and wheat; oat and rye were intermediate. However, the ingestion duration per insect did not show significant difference among foods. Results demonstrated that D. furcatus spent more time overall in probing activities on soybean and oat; whereas, rye and barley presented the worst feeding behavior. This study provides important background information for further quantitative studies of stink bugs on different plants, such as development of resistant host plants.

Susceptibility of Euschistus heros and Dichelops furcatus (Hemiptera: Pentatomidae) to Selected Insecticides in Brazil.

Euschistus heros (Fabricius, 1798) and Dichelops furcatus (Fabricius, 1775) are key pests of agricultural crops in Brazil. Chemical insecticides are the main control tactic used against these species. Here, we investigated the susceptibility of E. heros and D. furcatus from distinct regions to the mains insecticides used to stink bugs control in Brazil. Field populations of these species were collected throughout the 2017-2019 crop seasons and insects were exposed to insecticides in dip-test bioassays using fresh green bean pods. Populations of E. heros exhibited low variation in the susceptibility to acephate (LC50 = 172.2 to 1,008 µg a.i. per ml), and thiamethoxam (LC50 = 28.8 to 433.9 µg a.i. per ml); resistance ratios were less than 5.9- and 15.1-fold, respectively. In contrast, these populations had higher variation in the susceptibility to bifenthrin (LC50 = 26.7 to 636.1 µg a.i. per ml) and lambda-cyhalothrin (LC50 = 10.0 to 636.1 µg a.i. per ml); resistance ratios reaching 23.8- and 63.6-fold, respectively. Susceptibility monitoring data indicated a higher susceptibility of E. heros to the manufacturers field-recommended rates of acephate, lambda-cyhalothrin + thiamethoxam, and bifenthrin + acetamiprid than lambda-cyhalothrin. Populations of D. furcatus exhibited low variation in the susceptibility to acephate (LC50 = 219.2 to 614.1 µg a.i. per ml), bifenthrin (LC50 = 62.8 to 197.4 µg a.i. per ml), and lambda-cyhalothrin (LC50 = 189.5 to 2,538 µg a.i. per ml); resistance ratios were less than 13.4-fold. In summary, populations of E. heros are less susceptible to pyrethroids, while populations of D. furcatus have similar susceptibility to the insecticides evaluated.

Diversity of stink bugs (Pentatomidae) in Chloris distichophylla Lag. (Poaceae) overwintering

The objective of this study was to evaluate the diversity and abundance of stink bugs in Chloris distichophylla Lag (Poales: Poaceae) during the soybean and corn off-season. The work was carried out in the municipality of Cruz Alta, Rio Grande do Sul state, over the soybean and corn off-season between 2014 and 2018. 3543 adults were identified into six species: Euschistus heros (Fabricius, 1798), Dichelops furcatus (Fabricius, 1775), Dichelops melacanthus (Dallas, 1851), Edessa meditabunda (Fabricus, 1794), Edessa ruformaginata (De Geer, 1773) and Piezodorus guildinii (Westwood, 1837) (Hemiptera: Pentatomidae). E. heros was the most abundant, followed by D. furcatus. The diameter of the clumps directly affects the population density of the stink bugs. Finally, C. distichophylla is shown as favorable to the maintenance of the stink bug populations over the soybean and corn off-season.

Stink Bugs Nymph and Adult Biology and Adult Preference on Cultivated Crop Plants in the Southern Brazilian Neotropics.

Laboratory studies were conducted with Dichelops furcatus (F.), Euschistus heros (F.), and Nezara viridula (L.) (Heteroptera: Pentatomidae) aiming to evaluate nymph and adult biology and adult preference for immature reproductive structures of the cultivated plants, soybean, Glycine max (L.) Merrill (Fabaceae), wheat, Triticum aestivum L. (Poaceae), and canola, Brassica napus L. var. oleifera (Brassicaceae). Considering the survivorship for D. furcatus nymphs, it was greater on soybean and wheat, for E. heros nymphs it was greater on soybean compared to canola and wheat, and for N. viridula nymphs the survivorship was greater on soybean and canola. Dichelops furcatus nymphs developed faster on soybean and wheat, and E. heros and N. viridula nymphs developed faster on soybean and canola. Body weight at adult emergency for D. furcatus was greater on soybean and wheat, and for E. heros and N. viridula, it was greater on soybean. Adult survivorship and longevity were similar on soybean/wheat/canola for D. furcatus and N. viridula, and greater on soybean for E. heros. Reproduction and weight gain of adults were greater on soybean and wheat for D. furcatus, and on soybean for E. heros; N. viridula reproduced only on soybean and tended to gain greater body weight in this food source. As expected, soybean considering its superior nutritional quality was, in general, the best food. These laboratory studies coupled with field observations allow to conclude that the sequence of soybean/wheat/canola crops in the area studied forms a 'green bridge' that favor stink bug populations abundance in southern Brazilian neotropics.

Integrating data to redescribe Euschistus taurulus Berg (Hemiptera: Pentatomidae).

The genus Euschistus Dallas includes 67 species restricted to the New World, and several species are registered on cultivated plants in the Nearctic and Neotropical regions. In South America, most Euschistus species are completely overlooked due to the lack of information to allow accurate identification. Here, we redescribed Euschistus taurulus Berg, including for the first time, characterization of the internal and external genitalia of both sexes. We also report original information on bionomics, review and update information on geographical distribution and host plants records. Additionally, we provide DNA barcoding sequences for E. taurulus and three other morphologically similar key-agriculture pest species in South America: Euschistus heros (Fabricius), Dichelops melacanthus (Dallas), and Dichelops furcatus (Fabricius). We discuss means for correct identification of E. taurulus and its phylogenetic position within Euschistus and other similar stink bugs; the potential economic importance of the E. taurulus is also addressed.

Polyandry and trade-off between fecundity and longevity in female Dichelops furcatus (Hemiptera: Pentatomidae).

A trade-off is a relationship between two life history characteristics principally reproduction and adult longevity that are fundamental in predicting the optimal life history in any given environment. Mating is indispensable for sexual reproduction, but also can impose risks to females. Nevertheless, in the majority of insects, females allow multiple mating. Dichelops furcatus (Hemiptera: Pentatomidae) is a pest of wheat and corn in Argentina and southern Brazil, but little is known about its reproduction (i.e., the characteristics of the process that results in offspring). We analyzed reproductive attributes of D. furcatus, and the effect of single mating vs. multiple matings, evaluating the trade-off between fecundity and adult female longevity. We found that mating is not required for D. furcatus to oviposit, and multiple copulations were costly in terms of reduced longevity. Although multicopulated females lived a shorter period, only the pre- and post-reproductive periods were shortened. Fecundity was not affected but fertility was incremented in multicopulated females. Females copulated only once oviposited most of the eggs in the first half of the reproductive period, while eggs oviposited in the second half were all inviable (did not hatch). Studying demographic attributes of phytophagous insects provides relevant information to better understand the population dynamics of pests.

The underestimated role of pest pentatomid parasitoids in Southern South America

Stink bugs are pests of economic importance of extensive crops (commodities) in the Neotropics, particularly in Southern South America. They are abundant, have a broad geographical distribution, and cause severe damage. Main species include the Neotropical brown-stink bug, Euschistus heros (F.), the red-banded stink bug, Piezodorus guildinii (Westwood), the Southern green stink bug, Nezara viridula (L.), the green-belly stink bugs, Dichelops furcatus (F.), and D. melacanthus (Dallas), and the brown-winged stink bug, Edessa meditabunda (F.). The management of these pest species on crops is complex because they can cause economic damage in low numbers, and it is difficult to control by the commonly used insecticides. Therefore, biological control appears as the most important tactic to be implemented in stink bug management programs. Among the many natural enemies present on the various agroecosystems, egg parasitoids (Hymenoptera) and parasitoids of adult stink bugs (Diptera and Hymenoptera) are the most promising groups to be exploited as biological control agents of pest species. Despite attempts in the past, implementation of biological control of stink bugs on major commodities in Southern South America still remains at a low level of adoption, and its high potential is, generally, underestimated. In this review article, we present extensive data from the literature on the two main groups of biological control agents referred above. Moreover, we discuss ways to promote biological control as the most important tactic to manage stink bugs in Southern South America.

Saccharum angustifolium (Nees) Trin. (Poales: Poaceae) as hibernacle for stink bugs during the soybean and corn off-season in Southern Brazil

ABSTRACT Host plants are key factors in the survival of true bugs during unfavorable periods. The objective of this study was to evaluate the composition, diversity and abundance of pentatomid bugs in Saccharum angustifolium (Nees) Trin. (Poales: Poaceae). Plants were evaluated during the soybean and corn off--season for five years. A total of 250 plants were sampled, the true bug population was counted and used for statistical and faunistic analysis. We observed the occurrence of the species: Euschistus heros (F.), Dichelops furcatus (F.), Dichelops melacanthus (Dallas), Edessa meditabunda (F.), and Edessa ruformaginata (De Geer). Among the species, the highest population density was verified for E. meditabunda, E. heros, and D. furcatus. We also observed a direct effect of the clump diameter on the population density of E. heros, D. furcatus, and E. meditabunda. Finally, we conclude that S. angustifolium plants serve as adequate hibernacles for the survival of true bugs of economic importance during the soybean and corn off-season.

Diversity of Stink Bugs (Pentatomidae) Associated with Canola: Looking for Potential Pests.

Canola (Brassicaceae: Brassica spp.) is an important feedstock for biodiesel production and a potential ingredient for use in the food industry. In different continents, various arthropod pests damage canola plants. Stink bugs (Heteroptera: Pentatomidae) are present in all zoogeographical regions, and many species are recognized by their economic importance as crop pests. Our aim was to describe the composition, structure, and diversity of the assemblage of stink bugs sampled on canola in southern Brazil. A total of 878 pentatomids were captured, belonging to 27 species. The dominant species were Euschistus heros (F.) (n = 439), Dichelops furcatus (F.) (n = 160), and Nezara viridula L. (n = 79). The species richness estimators indicated the samples correspond from 79.7 to 93.1% of the richness estimated. Comparing canola to other monocultures, the richness of Pentatomidae was much superior. Otherwise, when compared to studies conducted in native vegetation and urban fragments, the richness is similar, and sometimes higher. This relatively high number of associations brings out the vulnerability of the canola fields according to the expansion of its cultivated area. Nine species of Pentatomidae are recorded on canola for the first time in Brazil. The most abundant species reported here are often stressed as stink bugs of economic importance in agro-ecosystems. The economic importance of each species varies greatly depending on the plant attacked. Detailed studies are needed to evaluate the damage caused to canola by stink bugs.

Development of Dichelops furcatus (Hemiptera: Heteroptera: Pentatomidae) Reared on Spring Cereals Versus Soybean.

The performance and preferences of the stink bug, Dichelops furcatus (F.), for spring cereals (wheat, rye, triticale, oat, and barley) were compared in the laboratory to their preferred host crop, soybean pods. Nymphs took significantly less time to reach adulthood on soybean pods compared to those fed seed heads of the five spring cereals tested. Wheat and rye yielded the longest developmental times, while nymphs fed triticale, oat, or barley developed faster, but still not as fast as those reared on soybean pods. On all foods ≥78% of nymphs reached adulthood. Adult body weight was significantly greater on soybean pods than on any of the spring cereals, and adults increased in body weight on all food sources tested. Fecundity was significantly greater for females fed soybean pods than those reared on the cereals. Egg viability was ≥66.9% except for bugs fed triticale (31.4%). In general, adult D. furcatus preferred soybean pods to seed heads of spring cereals, with wheat being preferred over the other spring cereals.

A new species of Hexacladia Ashmead (Hymenoptera, Encyrtidae) and new record of Hexacladia smithii Ashmead as parasitoids of Dichelops furcatus (Fabricius) (Hemiptera, Pentatomidae) in Argentina

Pentatomid adults of the species Dichelops furcatus (F.), collected on stubble of soybean, Glycine max (Linnaeus) Merril, in Santa Fe province of Argentina, were found parasitized by two encyrtid wasp species (Hymenoptera: Encyrtidae). One of the encyrtids is described as Hexacladia dichelopsis Torréns &amp; Fidalgo, sp. n., from both sexes, and the other species H. smithii Ashmead, is recorded for the first time from D. furcatus in Argentina. Both species are gregarious endoparasitoids which carry out the whole development (larval and pupal) in their living hosts; they emerge as imagoes, by cutting their way out through the dorsal wall of the abdomen. Including the newly described H. dichelopsis, seven species of the genus are recorded from South America, and an identification key to separate them is presented.

Probing Behavior of Dichelops furcatus (F.) (Heteroptera: Pentatomidae) on Wheat Plants Characterized by Electropenetrography (EPG) and Histological Studies.

The stink bug Dichelops furcatus (F.) (Heteroptera: Pentatomidae) has increased in abundance in recent years on the wheat, Triticum aestivum L., crop cultivated in the southern region of Brazil. To investigate the probing (stylet penetration) behaviors and nonprobing behaviors of D. furcatus on wheat plants, the electrical penetration graph or electropenetrography (EPG) technique was applied. Nine EPG waveforms (types/subtypes) were identified and described on stem and on ear head of wheat plants, as follows: Z, Np, Df1a, Df1b, Df2, Df3a, Df3b, Df4a, and Df4b. For the waveforms Df1, Df2, Df3, and Df4, stylets were severed to determine, via histological studies, the location of the stylet tip and/or salivary sheath tip in plant tissue. Waveform Z was visually correlated with the bug standing still on the plant surface, whereas during Np the bug was walking. Df1a and Df1b represent initial stylet insertion, deep penetration of the stylets into the plant tissue, and secretion of salivary sheath. Df2 represents xylem sap ingestion on stem and on ear head. Waveforms Df3a and Df4a were related to the cell rupturing feeding strategy (laceration and maceration tactics) on stem and on ear head (seed endosperm), respectively. Waveforms Df3b and Df4b represent ingestion of cellular contents derived from cell rupturing activities on stem and on ear head (seed endosperm), respectively. With this fundamental knowledge in hand, future studies can use EPG to develop novel pest management solutions.

Effect of green-belly stink bug, Dichelops furcatus (F.) on wheat yield and development

The green belly stink bug, Dichelops furcatus (F.) (Hemiptera: Heteroptera: Pentatomidae) is a pest of corn and soybean in southern Brazil. It also occurs on wheat, but information on its damage to this crop is limited. To determine the need for sustainable IPM programs, the impact of this bug on wheat production should be determined. Studies were conducted in the screenhouse with 1, 2 and 4 bugs caged for 16 days on single plants, cv. ‘BRS Parrudo’. During the vegetative period (plants ca. 25 cm tall), all infestation levels significantly reduced plant height and ear head length, but did not reduce grain yield. Feeding damage caused tissue necrosis on leaves. During the booting stage, grain yield was significantly reduced with 2 and 4 bugs per plant; ear heads were small, discolored and abnormally developed. In 2013 and 2014 field trials, plants were infested for 18 days with 2, 4 and 8 bugs per m2 at vegetative, booting, and milky grain stage. At these infestation levels, there was no significant reduction in grain yield. There was a significant decrease in the number of normal seedlings resulting from seeds exposed to 8 bugs per m2 at the milky grain stage. Results suggest that, in general, there is no need to control D. furcatus on wheat, unless numbers are ≥8 bugs per m2 during reproductive period.

Interactions of Selected Species of Stink Bugs (Hemiptera: Heteroptera: Pentatomidae) from Leguminous Crops with Plants in the Neotropics

Herein we discuss the interactions of selected species of phytophagous stink bug observed on leguminous (Fabaceae) crops in the Neotropics (Neotropical Region) with their associated plants. We included the following pentatomid species: Nezara viridula (L.), Piezodorus guildinii (Westwood), Euschistus heros (F.), Edessa meditabunda (F.), Dichelops furcatus (F.), Dichelops melacanthus (Dallas), and Thyanta perditor (F.). Based on a literature review, a list of plants on which these stink bug species were intercepted is included, indicating the reproductive hosts, i.e., plants on which bug can complete development, and incidental records, i.e., plants on which bugs are found occasionally. The change in feeding habits (from fruits/seeds of preferred host plants) to less preferred vegetative structures (stems/leaves of less preferred associated plants) for feeding or shelter, due to change in the landscape by intense multiple cropping and no-tillage cultivation systems is discussed.

Populations of phytophagous bugs influenced by crop background and wild plants

Plant-insect interaction governs the dynamics of insect populations with respect to their interrelation with the environment. The objective of the present study was to identify the influence of antecedent crops, species and diameters of wild plants on the quiescent population of phytophagous stink bugs. The experiment was conducted in the months of June and July in Parada Link, municipality of Santa Maria, Rio Grande do Sul state, Brazil in two fields under crops of rice and soybean. In the off season, alternative host wild plants such as Andropogon bicornis , Andropogon lateralis , and Erianthus angustifolius with 10, 20, 30 and 40 cm in diameter were selected. Six wild plants were sampled for each crop, species, and diameter, totaling 144 experimental units. The stink bug species were identified and quantified. Soybean and rice previous cultivation, as well as the species and diameter of the wild plant, influence the quiescent population of Dichelops furcatus , Edessa meditabunda , E. rufomarginata , Euchistus heros , Piezodorus guildinii , and Tibraca limbativentris phytophagous stink bugs. The host plants A. bicornis , A. lateralis , and E. angustifolius were utilized for the maintenance of the populations of phytophagous stink bugs in the off-season periods. Soybean cultivation in floodplain areas has a negative impact on the quiescent population of T. limbativentris .

Pentatomids associated with blackberry

Information concerning the presence of stink bugs in blackberry (Rubus spp.) in Brazil is sparse. This study aimed to identify the stink bug species associated with blackberry, to establish the daily dynamics and evaluate the fruits damage. The experiment was conducted in Santa Maria, Rio Grande do Sul State, Brazil, in blackberry orchard. Presence and evaluations of stink bugs were done weekly through visual and sweeping samplings at different day times. Five species of pentatomids were identified: Piezodorus guildinii, Nezara viridula, Euschistus heros, Dichelops furcatus and Edessa meditabunda. The bugs attack the drupelets producing a dark brown spot and wrinkled berries.