Rice Stink Bug Research Articles

Evaluating Behavioral Responses of Selected Stink Bugs (Hemiptera: Pentatomidae) to Spinosad

Southern green stink bug, Nezara viridula (L.) and redbanded stink bug, Piezodorus guildinii (Westwood) are two of the most important seed sucking pests affecting Louisiana soybean production and rice stink bug, Oebalus pugnax (F.) is an important late season pest in Louisiana rice. Exploration of chemicals that exhibit attraction or repellent activities toward major stink bug species would be beneficial in developing push-pull strategies. Spinosad is a commercially available natural insecticide that may have arrestant, attractant, or phagostimulant properties against stink bugs. To test this, a series of laboratory experiments were conducted to investigate the tactile, olfactory, and feeding responses of these stink bugs toward two commercial spinosad products (Entrust and Tracer) and technical grade spinosad. In tactile assays, female and male redbanded stink bug were arrested by Entrust, Tracer, and technical grade spinosad, whereas only rice stink bug and southern green stink bug males were arrested by Entrust. Y-tube assays revealed no attraction to any of the products by either male or female rice stink bug, redbanded stink bug, or southern green stink bug. In paired (treated or untreated soybean seed) feeding preference experiments, southern green stink bug showed no preference for any treatment, whereas redbanded stink bug fed more on Entrust- and Tracer-treated seed. From these results, spinosad appears to have an arrestant and phagostimulant effect on redbanded stink bug in the laboratory.

Effect of Spray Volume and Active Ingredient Rates on Insecticidal Control of a Rice Stink Bug (Hemiptera: Pentatomidae) Complex in Florida Rice

Effect of Spray Volume and Active Ingredient Rates on Insecticidal Control of a Rice Stink Bug (Hemiptera: Pentatomidae) Complex in Florida Rice

Reexamination of the Influence of Oebalus pugnax (Hemiptera: Pentatomidae) Infestations on Rice Yield and Quality.

The rice stink bug, Oebalus pugnax (F.), is the most important pest of headed rice, Oryza sativa L., in the United States. Numerous studies have attempted to quantify the impact of O. pugnax feeding on rice yield and grain quality, but these studies have often produced conflicting results. Across mid-south U.S. rice, thresholds based on sweep net sampling are used to determine the need for insecticide applications, but few studies have related sweep net captures to rice quality parameters. Field trials were conducted in Louisiana in 2015 and 2016 that used different rates of insecticides to establish rice plots with mean O. pugnax infestations ranging from 0.8 to 24.6 insects per 10 sweeps. Insecticide applications improved panicle weight and head yields as well as decreased percentage peck. A series of linear regressions examined relationships between O. pugnax captures and rice yield and quality parameters, including panicle weight, head yield (% whole kernels), and peck (discolored grains). Mean O. pugnax sweep net captures across all sampling dates in both years were significantly and negatively correlated to panicle weight and head yield and positively correlated to percentage peck. Peck was negatively correlated with head yield. Results from sampling at different maturity stages indicate sweep net captures at grain fill and soft dough stages had the greatest influence on rice yield and quality parameters, respectively. Further research into impacts of milling quality reductions on farm revenue and the influence of cumulative infestations over grain development is needed to improve economic thresholds for O. pugnax in rice.

Relative Abundance of the Stink Bug (Hemiptera: Pentatomidae) Complex Infesting Rice in the Everglades Agricultural Area of Florida.

Florida's rice stink bug complex comprises three species; Oebalus pugnax (F.), O. insularis (Stal), and O. ypsilongriseus (DeGeer), the latter two of which are invasive and exclusive to Florida within the United States. A series of surveys were conducted in 2017 and 2018 to determine the relative abundance of the three species throughout Florida's rice growing region within the Everglades Agricultural Area, in addition to comparing their seasonality within crop and noncrop habitats. Sampling occurred in commercial rice fields and adjacent transects of graminaceous noncrop hosts using sweep nets. Oebalus pugnax (52.7%) and O. insularis (61.7%) were the most abundant species in 2017 and 2018, respectively. Both species were more prevalent in rice fields compared to transects of noncrop hosts. Oebalus ypsilongriseus remained in low abundance relative to O. pugnax and O. insularis, and did not differ in numbers collected among rice and noncrop hosts. Of the noncrop hosts in transects, Panicum dichotomiflorum (fall panicum) was the most abundant across both years. This study is the first report of Oebalus species feeding on Echinochloa crus-galli (common barnyardgrass) in Florida. This study shows that the invasive O. insularis continues to increase in abundance, and has surpassed O. pugnax in terms of regional populations. These results emphasize the need for additional studies to assess the interactions among O. insularis and other Oebalus species in addition to its feeding behavior in Florida rice.

The role of Oryza sativa L. 'Milyang 44' husks on the resistance to two rice stink bugs.

To elucidate the resistance mechanisms of the rice (Oryza sativa L.) cultivar ‘Milyang 44’ against rice stink bugs, we compared the number of stylet sheaths, husk perforations, and feeding marks on the surface of the grains caused by Leptocorisa chinensis and Cletus punctiger on Milyang 44 and the control cultivar, i.e., ‘Aichinokaori SBL’. We also examined the cross-sectional structure of the rice husks. We found that the number of stylet sheaths per panicle was higher in Milyang 44 than in Aichinokaori SBL for both rice stink bug species, except in one test involving C. punctiger. However, Milyang 44 had significantly less damage per number of stylet sheaths than Aichinokaori SBL, resulting in a lower percentage rates of pecky rice grains in Milyang 44. Interestingly, there was no difference in the percentage rates of pecky rice between the two cultivars after removing one third of the husks. Histological analysis showed that the sclerenchymatous cell wall containing lignin of husk was thicker in Milyang 44 than in Aichinokaori SBL, suggesting that the husk of Milyang 44 plays an important role in its resistance to these two rice stink bug species.

Importance of native vegetation for detection and management of rice stink bug (Tibraca limbativentris)

Tibraca limbativentris (Hemiptera: Pentatomidae) is a major pest in Neotropical rice agroecosystems. In autumn-winter, this pest takes refuge in rice stubble and in native vegetation, which allows it to re-colonize the crop during the rice growing season. However, it is still unknown whether this vegetation is a pest sink or is actually a natural trap that contributes to pest population biocontrol. Here we present information on the insect's alternative host plants, a preliminary outline of the relationship between plant phylogeny and insect abundance, and the impact that winter natural enemies have in pest population. Also, we include a proposed methodology for pest density analysis in winter hosts. Our results show significant differences in the abundance/density that T. limbativentris reaches in the 12 host plant species present in our study areas, with a plant-use pattern significantly related to the phylogenetic clade of Poales. Stink bug winter populations mainly comprised diapause adults, and 40% of insect digestive tracts had content. Survival of T. limbativentris was 56.92% in winter hosts. About mortality, 10% was due to undetermined causes and 33.08% due to entomopathogenic fungi, showing a natural regulation of the pest population. Our results suggest that native vegetation impacts winter survival of T. limbativentris. Although these plants offer shelter, they offer a greater contribution to Integrated Pest Management: the natural regulation of winter pest populations through entomopathogenic attack. Further studies on T. limbativentris population dynamics and the preservation of native areas near rice fields will be required for the development of best control practices.

Susceptibility of Rice to Oebalus pugnax (F.) (Hemiptera: Pentatomidae) Feeding at Different Levels of Grain Maturity and Impacts on Insecticide Termination.

The stages of rice, Oryza sativa L. (Poales: Poaceae), grain maturity that are most susceptible to rice stink bug, Oebalus pugnax (F.), damage have been identified; however, the stage at which they are no longer capable of causing appreciable damage during grain maturity is unclear. The objective of this study was to determine the susceptibility of rice to rice stink bug feeding at different levels of grain maturity and determine an insecticide termination timing. Rice stink bug damage was examined using five levels of grain maturity described as percent of kernels reaching mature straw coloration referred to as hard dough (20, 40, 60, 80, and 100%) across a range of infestation levels using single panicle sleeve cages and large cages. Hybrid and conventional cultivar rice panicles at 20, 40, and 60% hard dough were found to be susceptible to indirect yield loss, as two rice stink bugs per panicle resulted in over 7% peck. In large cage trials, 25 rice stink bugs caused 0.7-1% peck to hybrid and conventional rice plots at 20% hard dough. Much less damage was observed once rice reached 60% hard dough, where peck averages only reached 0.4%. Decreased damage at 60% hard dough was validated using uncaged trials where 0.4% additional peck was observed in unsprayed plots. These data indicate that rice in the early stages of hard dough is susceptible to large levels of indirect yield loss, but unless significant densities of rice stink bug are present at 60% hard dough, no more sampling or applications are necessary.

Flutuação populacional e controle de pragas: estudos de caso com pragas de arroz irrigado

Abstract – Population fluctuation studies are very important for pest control, since they provide fundamental information on when and in what intensity a harmful organism can arise in crops, thus providing a greater accuracy in the application of control measures. The population fluctuation of the South American rice water weevil (Oryzophagus oryzae), of the rice stink bug (Oebalus spp.), and of the rice caseworm (Nymphula spp.) in irrigated rice fields were related to the crop management. For these species, control measures can be planned and implemented based on population fluctuation studies.

Influence of Sweep Length on Rice Stink Bug (Hemiptera: Pentatomidae) Capture and Reliability of Population Density Estimates.

The rice stink bug, Oebalus pugnax (F.), is a key pest of heading rice, Oryza sativa L. (Poales: Poaceae), in the southern United States. Sweep net sampling is the recommended method for sampling rice stink bug in rice, but there currently exists no specific recommendation for sweep length, and a large amount of variation likely exists amongst samplers. The objectives of this study were to determine the role that sweep length plays in sampling accuracy and determine the feasibility of using sweep lengths smaller than 180°. When monitoring sweep lengths by consultants, producers, and researchers, a large amount of variation in sweep length and a significant linear relationship between sweep length and rice stink bug catch per 10 sweeps was observed. Sweep length was then controlled at three levels (0.8, 1.8, and 3.5 m) and a change from 0.8 to 1.8 m in sweep length led to an increase on average of 2.28 rice stink bugs per 10 sweeps. These data suggest knowledge of sweep length is vital, and paired with large amounts of observed variation in sweep length, recommending a specific sweep length is ideal. Using Taylor's values, it was determined that 1.8 m sweeps resulted in density estimates that were as reliable as 3.5 m (180°) sweeps, suggesting a longer sweep length was not necessary. A 1.8 m sweep length recommendation would create an easier sampling regimen that is still reliable, which could lead to more accurate action threshold decisions being made for rice stink bug if it increases adoption in consultants and producers.

Direct and Indirect Effects of Herbicides on Insect Herbivores in Rice, Oryza sativa

Densities of insect pests in agricultural communities may be affected by herbicides commonly used for weed management via several routes. First, herbicides may cause direct mortality to insects present both during and immediately following application. Second, herbicides may induce plant defenses that increase resistance to insect herbivores. Third, herbicides may alter the quantity and composition of weed populations, which in turn may change the structure of insect communities found subsequently in the crop. This study was designed to investigate the effects of an array of herbicides on the densities of several major pests found in rice in the southern United States. These pests included the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), the rice stinkbug, Oebalus pugnax (Fabricius) (Hemiptera: Pentatomidae), and a stemborer complex comprised of three lepidopteran species (Lepidoptera: Crambidae). Insects directly exposed to herbicides experienced high mortality; while those fed leaf material that had been exposed to herbicides did not. Herbicide application did not significantly increase resistance in rice to subsequent herbivore infestation. Results provided modest support for the third hypothesis represented by positive correlations between weed densities and insect pest densities.

The Cotton Boll: Temporal Susceptibility of the Boll Wall to Stylet Penetration by Hemipteran Pests

Cotton (Gossypium hirsutum L.) is a high‐value cash crop that is injured by various hemipteran insects, including lygus bugs (mirids) and stink bugs (pentatomids). Stink bugs can transmit pathogens that cause seed and boll rot of cotton, and lygus bugs can also transmit pathogens. However, the temporal susceptibility to breaching of the boll wall by stink bugs and related species was unknown. Our objective was to compare known estimates of stylet penetration for mirids (Lygus lineolaris Palisot de Beauvois and Pseudatomoscelis seriatus Reuter) and pentatomids [Chinavia hilaris Say, Euschistus obscurus (Palisot), Euschistus servus (Say), Euschistus tristigmus (Say), Nezara viridula (L.), Oebalus pugnax (F.), Piezodorus guildinii Westwood, and Thyanta custator accerra McAtee] against observed minimum boll wall thickness in multiple entries from four Gossypium species to determine the time at which bolls initially become susceptible to stylet penetration. Results show that P. seriatus could not breach the boll wall. Lygus lineolaris could breach the wall at ≤7 d after flowering in G. herbaceum L. and in select entries of G. hirsutum. All the pentatomids could breach the boll wall at 1 d after flowering, and virtually all could continue to breach the wall throughout the entire production season. Monitoring efforts for stink bugs may need to be implemented at boll set to mitigate introduction of pathogens and yield losses given the season‐long susceptibility to stink bugs.

Stink bug rostrum length vs. stylet penetration potential

AbstractStink bugs (Hemiptera: Pentatomidae) and related species continue to plague cotton, Gossypium hirsutum L. (Malvaceae), worldwide. Stink bugs utilize their stylets (housed within the rostrum) to feed upon cotton bolls and transmit pathogens that cause seed and boll rot of cotton. Stylet penetration potential of stink bugs is influenced by species and recent observations indicated a phenomenon whereby stink bugs with shorter rostra yielded deeper stylet penetration estimates. The objective of this study was to elucidate the relationship between rostrum length and known stylet penetration estimates for two pairs of similar‐sized pentatomid species: Chinavia hilaris (Say) vs. Euschistus servus (Say), and Oebalus pugnax (Fabricius) vs. Piezodorus guildinii Westwood. For each species, individual rostral segments were measured to yield total lengths, and measurements were compared against known stylet penetration estimates. Chinavia hilaris and P. guildinii have longer rostra than E. servus and O. pugnax, respectively, yet E. servus and O. pugnax yielded deeper stylet penetration estimates. Deeper stylet penetration by species with shorter rostra can be attributed to differences in the lengths of rostral segments 1 and 2. Euschistus servus and O. pugnax each had significantly longer rostral segments 1 and 2 than C. hilaris and P. guildinii, respectively. Also, the cumulative lengths of rostral segments 1 and 2 comprised a higher overall proportion of the entire rostrum length in E. servus and O. pugnax vs. C. hilaris and P. guildinii, respectively. Rostral segments 1 and 2 are instrumental in the feeding mechanics of these phytophagous species; it is clear that their greater length and their role in stylet penetration model calculations – including the lengths of segments 3 and 4 – override the presumption that total rostrum length equates to stylet penetration potential. This novel finding contributes to the general knowledge of stink bug feeding mechanics.

Cover Image, Volume 75, Issue 3

The front cover image is based on the Research Artice Effects of exogenous methyl jasmonate and salicylic acid on rice resistance to Oebalus pugnax by Thais F Stella de Freitas et al., DOI: 10.1002/ps.5174. Image Credit: Thais Fernanda Stella de Freitas, Federal University of Rio Grande do Sul. image

Effects of exogenous methyl jasmonate and salicylic acid on rice resistance toOebalus pugnax

After herbivore attack, plants express inducible resistance-related traits activated by hormones, mainly jasmonic acid (JA) and salicylic acid (SA). Methyl jasmonate (MeJa) is a biologically active methyl ester of JA. Exogenous applications of JA, SA, and MeJa induce responses similar to herbivory by insects. In this study, rice, Oryza sativa L. (Poaceae), plants were treated with two concentrations of MeJa (2 and 5 mmol L-1 ), two concentrations of SA (8 and 16 mmol L-1 ) and herbivory to evaluate effects of elicitation and herbivory on resistance to the rice stink bug (RSB) Oebalus pugnax Fabricius, 1775 (Hemiptera: Pentatomidae), an injurious insect pest of rice in the United States. Nymphs developing on plants treated with SA 16 mmol L-1 took longer to reach adulthood than nymphs developing on check plants. Grains per panicle were higher in plants treated with SA 16 mmol L-1 and MeJa in both concentrations than in check treatment. Plants treated with SA emitted five of six volatile compounds identified in equal or higher amounts than plants subjected to previous herbivory, particularly methyl salicylate, a known defense-related compound. Salicylic acid 16 mmol L-1 was the treatment that elicited the highest amount of all volatiles. In the field assay, plots treated with SA 16 mmol L-1 showed lower spikelet sterility and a tendency for fewer bugs to be found in plots. Rice plants possess defense mechanisms that can be elicited using hormones as elicitors, mainly SA 16 mmol L-1 , to induce resistance against RSB. © 2018 Society of Chemical Industry.

Insecticidal Control for the Rice Stink Bug (Hemiptera: Pentatomidae) Complex Found in Florida Rice1

Currently, the rice stink bug complex (Hemiptera: Pentatomidae) attacking Florida rice is the most diversified and unique stink bug complex in United States rice production. This complex includes the common rice stink bug, Oebalus pugnax (F.), and two invasive species, Oebalus ypsilongriseus (DeGeer) and Oebalus insularis (Stal). Insecticidal efficacy for these two invasive species is not known. Insecticidal evaluations of five insecticides were made on adults of both sexes of the three species. Weights of adults were also determined. In all three species, females weighed more than males of the same species. Also, O. pugnax adults were the largest followed by O. ypsilongriseus, with O. insularis being the smallest adults. All five insecticides gave a high degree of control of 93–100% for both sexes of all three species. These data are currently useful to Florida rice growers and may be useful to rice growers in other states if the two invasive species spread to those states. These data also provide baseline data for future studies on development of insecticide resistance of the stink bugs in Florida rice.

Development of Rice Stink Bug,Oebalus pugnaxF., Nymphs on Rice Kernels and Effects of Nymphal Feeding on Rice Yields

The rice stink bug, Oebalus pugnax F., is of major economic importance to producers and millers of rice, Oryza sativa L. (Poaceae), because of the damaging effects of feeding during kernel development. Adult rice stink bugs cause yield loss and discoloration of rice kernels when feeding on panicles from anthesis to hard-dough stages of grain development, but damage by nymphs developing from the first to fifth instars has not been adequately studied. An experiment assessed the effect of rice stink bug nymphs on rice yield by caging egg masses on individual panicles and removing insects when adults emerged. A positive relationship between insect abundance and two measures of yield loss, unfilled kernels and milling loss, was very significant. Approximately 35% of eggs developed into fifth-instar nymphs in less than 21 days -- before kernels matured. Findings suggested that eggs and nymphs during early stages of rice panicle development should be considered in insecticidal treatment thresholds for rice stink bugs.

Expedient synthesis of bisabolenol stink bug pheromones via stereodefined cyclohex-2-enones

Abstract We recently synthesized all stereoisomers of 1,10-bisaboladien-3-ol and 10,11-epoxy-1-bisabolen-3-ol, including three stink bug pheromones, via a rhodium-catalyzed asymmetric addition of trimethylaluminum to diastereomeric mixtures of cyclohex-2-enones. However, yields of trans isomers were low, and scaling reactions using expensive catalysts were cumbersome. Now we describe a new synthesis of bisabolenol stink bug pheromones via ( S )- and ( R )-4-(( R )-6-methylhept-5-en-2-yl)cyclohex-2-enones prepared by enantioselective Michael additions of methyl vinyl ketone to ( S )- and ( R )-citronellals and lithium hydroxide monohydrate-catalyzed stereoselective cyclizations of intermediate ketoaldehydes. Addition of methyllithium to these enones provided cis - and trans -1,10-bisaboladien-3-ols, which were separated by chromatography on silica and further converted to 10,11-epoxy-1-bisabolen-3-ols. Thus, we developed more convenient syntheses of pheromones of the rice stink bug, the harlequin bug, and brown marmorated stink bug.

Evaluation of Foliar Insecticides for Control of Rice Stink Bug, 2016

Evaluation of Foliar Insecticides for Control of Rice Stink Bug, 2016

Evaluation of Foliar Insecticides for Control of Rice Stink Bug, 2016

Evaluation of Foliar Insecticides for Control of Rice Stink Bug, 2016

Stink Bugs (Hemiptera: Pentatomidae) in Pheromone-Baited Traps Near Crop Field Edges in Georgia, USA

Abstract Stink bugs (Hemiptera: Pentatomidae) are economic pests of cotton. Our specific objective for this 3 yr study was to use traps baited with Euschistus pheromone to monitor stink bugs in habitats near cotton and peanut field edges in Georgia, USA, before, during, and after crop growth and development. Plant-feeding stink bugs captured in traps included Euschistus servus (Say), E. tristigmus (Say), Chinavia hilaris (Say), Nezara viridula (L.), Hymenarchys nervosa (Say), E. ictericus (L.), Thyanta custator custator (F.), E. quadrator Rolston, Brochymena quadripustulata F., Proxys punctulatus (Palisot), and Oebalus pugnax (F.). Two predatory stink bug species, Podisus maculiventris (Say) and Euthyrhynchus floridanus (L.), also were captured. Euschistus servus was the predominant species captured, followed by E. tristigmus. In both cotton and peanut, traps with a pyramid-shaped base captured significantly more E. servus and E. tristigmus nymphs and adults than traps with a bamboo pole base, suggesting ...