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Identification and Functional Characterization of Sesquiterpene Pheromone Biosynthetic Genes in Stink Bugs (Pentatomidae)Lancaster, Jason 12 July 2018 (has links)
The stink bugs, (Pentatomidae) harlequin bug (Murgantia histrionica), brown marmorated stink bug (Halyomorpha halys), and southern green stink bug (Nezara viridula) are significant agricultural pests both in the United States and globally. The aggregation or sex pheromones produced by these insects are known to be bisabolene-type sesquiterpenoids; however, the biosynthetic pathways in the formation of these pheromones are unknown. Here we provide evidence that Pentatomidae produce sesquiterpene aggregation pheromones de novo and discuss the evolution of terpene biosynthesis in stink bugs. According to transcriptome analyses, the investigated stink bug species express at least two isoprenyl diphosphate synthases (IDSs), one of which makes (E,E)-farnesyl diphosphate (FPP) as the general precursor in sesquiterpene synthesis, whereas other IDS-type proteins function as terpene synthases (TPSs) generating intermediates in sesquiterpene pheromone formation. The TPS genes are expressed in a sex- and tissue-specific manner. Based on phylogenetic analysis, these IDS-type TPSs arose from trans-IDS progenitors in divergence from bona fide IDS proteins. Compared to microbes and plants, the evolution of TPS function from IDS progenitors in insects appears to have occurred more recently. The discovery of TPS genes in stink bugs provides valuable insight into pentatomid and insect terpene biosynthesis. Moreover, the identified genes may be used in developing alternative management strategies for stink bug pests. / PHD / The stink bugs harlequin bug, brown marmorated stink bug, and southern green stink bug are significant agricultural pests both in the United States and globally. These stink bugs, as many others, release terpene type pheromones for aggregation and mating. In contrast to the general notion that insects depend on their host plants or microbes as sources of terpene pheromones, we provide evidence that stink bugs produce these pheromones de novo. We found that stink bug pheromone formation depends on proteins with terpene synthase activity, which are derived from enzymes producing linear intermediates in the core terpene metabolic pathway (isoprenyl diphosphate synthases). Expression of the terpene synthase genes is confined to specific tissues of males according to the male-specific release of the pheromones. Compared to microbes and plants, the evolution of terpene synthase function from isoprenyl diphosphate synthase progenitors in insects appears to have occurred more recently. The discovery of terpene synthase genes in stink bugs provides valuable insight into pentatomid and insect terpene biosynthesis. Moreover, the identified genes may be used in developing alternative management strategies for stink bug pests.
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Resposta de genótipos de soja ao ataque de Euschistus heros (Hemiptera : Pentatomidae) /Victor, Vinícius Suárez January 2020 (has links)
Orientador: Edson Luiz Lopes Baldin / Resumo: A soja, [Glycine max (L.) (Merrill)] é um dos principais grãos produzidos mundialmente, com o Brasil apresentando grande destaque em produtividade e exportação. Diversos fatores podem comprometer a produção desta leguminosa, no qual o ataque de insetos fitófagos possui grande relevância. Dentre os insetos-praga para a cultura da soja, Euschistus heros (Fabricius) possui grande importância pela alta incidência no campo e elevado danos ocasionados. Como alternativa à baixa eficiência dos métodos de controle e aplicações indevidas de defensivos químicos, este trabalho procurou avaliar a tolerância de quatro genótipos de soja frente ao ataque de E. heros (3 percevejos/planta) em diferentes fases fenológicas (R3, R5, R7, R3 até o final do ciclo e controle) a campo em duas safras, e respostas enzimáticas, analisadas em laboratório, após o ataque de E. heros em casa de vegetação durante a fase fenológica R5 por diferentes períodos de infestação (7, 14, 21 dias). Para isto, foi avaliado a campo a produtividade, peso de 100 grãos, número de vagens/ 10 plantas, número de grãos/10 plantas, retenção foliar e nível de danos ocasionados. Em casa de vegetação avaliou-se produtividade da linha central, número de vagens e número de grãos. Posteriormente, em análises químicas realizadas em laboratório, foram avaliadas as atividades das enzimas peroxidase, polifenol oxidase, catalase, superóxido dismutase e proteínas totais solúveis. Os genótipos ‘Conquista’ infestado em R3, ‘IAC 100’ infestado... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
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Insect pest management in hemp in VirginiaBritt, Kadie Elizabeth 13 April 2021 (has links)
For the first time in many decades, a hemp pilot program was initiated in Virginia in 2016. Outdoor surveys were conducted in the 2017 and 2018 field seasons to record insect presence and feeding injury to plants. Multiple insect pests were present, including corn earworm (Helicoverpa zea [Boddie]) (Lepidoptera: Noctuidae), brown marmorated stink bug (Halyomorpha halys [Stål]) (Hemiptera: Pentatomidae), and cannabis aphid (Phorodon cannabis) (Hemiptera: Aphididae). In 2019, indoor production surveys revealed that cannabis aphid, twospotted spider mite (Tetranychus urticae Koch) (Acari: Tetranychidae), and hemp russet mite (Aculops cannabicola [Farkas]) (Acari: Eriophyidae) would likely cause production issues. Very little is known about the impact of insect defoliation in hemp so studies were conducted in 2018-2020 to determine impacts on yield and cannabinoid content of grain and cannabinoid variety hemp due to leaf surface area loss. In Virginia over two growing seasons, manual removal of leaf tissue in grain and CBD cultivars did not significantly impact observable effects on physical yield (seed or bud weight) or cannabinoid content (CBD or THC) at time of harvest. Corn earworm is the major pest of hemp produced outdoors and studies occurred to evaluate monitoring and management strategies. Pheromone traps may be valuable in determining when corn earworm moths are present in the vicinity of hemp fields but are not useful in predicting larval presence in buds or final crop damage. Larval presence and final crop damage are related. Brown marmorated stink bug does not appear to be a concern in hemp, at least at this time. / Doctor of Philosophy / For the first time in many decades, a hemp pilot program was initiated in Virginia in 2016. Outdoor surveys were conducted in the 2017 and 2018 field seasons to record insect presence and feeding injury to plants. Multiple insect pests were present, including corn earworm, brown marmorated stink bug, and cannabis aphid. In 2019, indoor production surveys revealed that cannabis aphid, twospotted spider mite, and hemp russet mite would likely cause production issues. Very little is known about the impact of leaf area loss due to insect feeding in hemp so studies were conducted in 2018-2020 to determine impacts on yield and cannabinoid content of grain and cannabinoid variety hemp due to leaf surface area loss. In Virginia over two growing seasons, manual removal of leaf tissue in grain and CBD cultivars did not significantly impact observable effects on physical yield (seed or bud weight) or cannabinoid content (CBD or THC) at time of harvest. Corn earworm is the major pest of hemp produced outdoors and studies occurred to evaluate monitoring and management strategies. Pheromone traps may be valuable in determining when corn earworm moths are present in the vicinity of hemp fields but are not useful in predicting larval presence in buds or final crop damage. Larval presence and final crop damage are related. Brown marmorated stink bug does not appear to be a concern in hemp, at least at this time.
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Habitat and host plant effects on the seasonal abundance of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) among fruit orchards in northern VirginiaHadden, Whitney Taylor 02 April 2021 (has links)
Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), brown marmorated stink bug, is an invasive, polyphagous pest that has disrupted integrated pest management programs in Mid-Atlantic tree fruit orchards since 2010. The amount of damage to fruit caused by H. halys feeding is highly variable, even within adjacent orchard blocks, and the influence of orchards and wild host plants nearby on H. halys relative abundance is unknown. Pheromone-based trapping studies conducted along woodland-to-orchard transects, along woodland borders at sites with and without adjacent orchards, and within the mid-canopy of several common wild host trees in woodland borders were used to investigate biotic factors underlying the variability of H. halys populations among sites within a geographically proximate area. Additionally, the retention duration of H. halys on wild and cultivated tree hosts was used as a proxy for host acceptability throughout the season. All trapping studies yielded significantly greater H. halys captures during the late season, and in the transect study, pyramid traps deployed at orchard and woodland edges during this period yielded the highest captures. The presence of orchards or open fields adjacent to woodlands had no significant impact on H. halys captures in sticky traps deployed along wooded edges, but captures varied significantly among orchard and open field sites. Among 11 common wild host plant genera surveyed at these sites, five genera, Elaeagnus, Fraxinus, Lonicera, Ailanthus, and Sassafras, were significantly related to H. halys relative densities. Conversely, studies measuring captures in small pyramid traps within the canopy of wild tree hosts revealed no significant differences among hosts at any point in the season, suggesting that this approach might not be appropriate for assessing host plant suitability. Finally, harmonic radar trials assessing host plant retention as a proxy for host suitability revealed that adults released on peach and pheromone-baited apple trees had significantly greater retention durations than those released on non-host, grass, and that adult retention duration increased from the early to late season. In combination, results indicate that the risk posed by H. halys to cultivated orchard crops varied across locations and seasonally, and may be related to the species composition of wild host trees in adjoining woodlands. / Doctor of Philosophy / Brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an invasive insect that has inflicted feeding damage on fruit grown in Mid-Atlantic orchards since 2010. The agricultural landscape in the Mid-Atlantic region complicates BMSB management, as many orchards are bordered by woodlots containing a variety of BMSB host plants. The amount of BMSB feeding injury at harvest can vary greatly among nearby orchards, and even within individual orchards, but it is unknown why these differences exist. Several BMSB trapping studies using pheromone-baited traps revealed that BMSB populations were greatest in the late-season, confirming previous work. Furthermore, captures in traps positioned in lines intersecting orchards and adjacent woodlots revealed late-season BMSB presence was greatest at the orchard and woodland edges. Captures in traps next to woodlots adjacent to orchards and open field sites indicated that the presence of orchards had no impact on captures, but that captures varied significantly among orchard sites and open field sites. A survey of the woody plants in the woodlots adjacent to these sites revealed that five host plant genera were strongly related to BMSB abundance. A study examining BMSB captures in small pyramid traps deployed in the canopy of several common wild tree hosts did not yield differences in captures among hosts at any point in the season, and thus was not a suitable method for assessing seasonal differences in BMSB host use. Finally, harmonic radar technology was used to assess how long BMSB remained on several wild and cultivated host plants at different points in the growing season, as a proxy for host suitability. Peach and pheromone-baited apple showed significantly greater adult retention durations than non-host, grass, and adults remained on host plants longer in the early than late season. Ultimately, these results should aid in the monitoring and management of BMSB by providing a broader understanding of factors underlying the presence and abundance of BMSB on a localized geographic scale.
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Factors Influencing Behavior of Overwintering Brown Marmorated Stink Bugs (Halyomorpha halys) in Human DwellingsChambers, Benjamin D. January 2017 (has links)
The brown marmorated stink bug (Halyomorpha halys) (Stål) is known for overwintering in human homes. Studies were conducted to understand the behavior of adult bugs in response to characteristics of potential overwintering structures including gap sizes, light, and presence of dead conspecifics. In a test where bugs were placed in increasingly tight boxes, most bugs settled in gaps 4.5 - 5.5 mm high. None settled in a space less than 3.5 mm high. In boxes with constant tightness, bugs tended to move to the back, and primarily settled along walls and in corners. In both box types, bugs tended to turn and face the cavity entrance during settling. In tests of responses of disturbed overwintering bugs to common household light bulbs over the course of a year, bugs were taken from shelters and exposed to lit bulbs. Bug responses were seasonal, with attraction to light bulbs in spring and summer, but little or no consistent response in fall or winter. The lack of response occurred more often at night than in afternoons. Because not all bugs survive the winter, corpses can accumulate. Single shelter-seeking H. halys were found not to respond to the presence of dead aggregations from the previous years unless touch was possible, in which case aggregations were joined. Dead aggregations from the same year had a repellent effect. Presence of a single dead bug from the same year did not provide any survivorship advantage to overwintering bugs. Results suggest possible improvements to trap shelters. / Master of Science in Life Sciences / The brown marmorated stink bug (Halyomorpha halys) is known for overwintering in human homes. This research investigated the responses of these bugs to some characteristics of overwintering structures, including crevice tightness preference, light sources, and dead bugs leftover from previous years. Tightness experiments indicated that bugs in crevices with hard walls prefer to settle in spaces between 4.5 and 5.5 mm high. Bugs also tended to stay on the floor, go back as far as they could, and face the entrance of the crevice. These findings will help improve overwintering box designs for collection and research, and will help pest control professionals focus their efforts. When bugs were disturbed and exposed to common household light bulbs, they tended to move toward the bulbs in late summer and in spring, but responded less in fall and winter, and responded more often in the afternoon than at night. Bugs were also exposed to other dead bugs in several ways. When lone bugs were exposed to groups of dead bugs from previous years, they went to them only if they could touch them. Single dead bugs had less of an impact. Exposure to groups of dead bugs from the same year drove live bugs away. Overwintering brown marmorated stink bugs do not appear to eat other bugs that have recently died. These results suggest several possible improvements to the designs of trap shelters used for research and control.
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Biology and Management of Brown marmorated Stink Bug, Halyomorpha halys (Stål), in Agricultural and Urban EnvironmentsAigner, John D. 29 April 2016 (has links)
Brown marmorated stink bug, Halyomorpha halys (Stål), is a crossover pest impacting agriculture and invading urban environments. Studies were conducted to better understand the management of the bug through its physiology, behavior and susceptibility to insecticidal intervention.
Halyomopha halys exhibit great variability in overwintering site selection with choices including manmade structures and tree bark. Because of these diverse sites, the bug must have the ability to withstand varying conditions throughout the overwintering cycle. We were able to determine that H. halys is chill intolerant and capable of adapting its tolerance to temperatures by season, sex, and location of acclimation. The mean supercooling point (± SEM) in the winter in Minnesota was -17.06°C ± 0.13° and in Virginia was -13.90°C ± 0.09°.
Laboratory experiments conducted in Blacksburg, VA were able to determine baseline lethal high temperatures over time against H. halys adults. To achieve 100% mortality, temperatures fell between 45°C and 50°C, 40°C and 45°C, and 42°C and 45°C, over 15-min, 1-h, and 4-h, respectively. Moving forward, we were able to utilize this information to develop heat treatment guidelines for export shipping cargo infested with overwintering H. halys. In a controlled field experiment, we determined that exposing the coldest areas of an infested vehicle to temperatures greater than 50°C for a minimum of 15 minutes resulted in 100% mortality of overwintering BMSB adults.
In 2012 and 2013, citizen scientists were recruited through Virginia Cooperative Extension to assist in evaluating several in home light traps designed to help eradicate overwintering H. halys adults in homes. Over the course of the two year study, fourteen houses participated in the study with 72% of those houses having stink bug activity. It was found that the most effective trap was an aluminum foil pan trap. In 2013, the trap was 19 times more effective at catching stink bug adults than any other trap tested.
In September of 2014, a near-field experiment was conducted to determine the residual efficacy of several recommended and labeled insecticides for treatment of homes against invading H. halys adults. This study used constructed window screen bags that were dipped in insecticide solution. After the initial treatment, bugs were exposed to the bags for 24h weekly, up to 54 days after treatment (DAT). It was determined that 2 DAT all insecticides had activity except for indoxacarb. All insecticides lost efficacy after 29 DAT except for lambda-cyhalothrin, beta-cyfluthrin, beta-cyfluthrin + imidacloprid, lambda-cyhalothrin + thiamethoxam, and dinotefuran, which had some measureable activity even after 40 DAT. Each of these insecticides contained a pyrethroid alone or in combination with a neonicotinoid.
Laboratory bioassays were conducted to determine the LC50 values of clothianidin, dinotefuran, imidacloprid, and thiamethoxam against H. halys nymphs using a systemic application method. Those LC50 values were found to be 0.077, 0.013, 0.068, and 0.018 ppm, respectively. Field experiments conducted in Virginia in 2012 and 2013 showed a significant reduction of stink bug damage using two soil applications of neonicotinoid insecticides in pepper and tomato. In North Carolina, a single drip irrigation application significantly reduced stink bug damage in 2012 and 2014 using dinotefuran or imidacloprid. / Ph. D.
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Murgantia histrionica (Hahn): new trapping tactics and insights on overwintering survivalDiMeglio, Anthony S. 19 December 2018 (has links)
Harlequin bugs are orange and black aggregation pheromone emitting stink bug pests, specifically of cole crops such as kale, broccoli and collards. This nearly loyal crop preference makes an interesting challenge for trapping them and helping farmers predict pest severity. Harlequin bugs can be found in much of North America, and are a serious problem in the southeastern United States. Presumably their persistence into northern regions is limited by extreme winters. In 2014 and 2015 the arctic polar vortex extended into mid-latitudes bringing a blanket of sustained sub-freezing temperatures to much of the United States. We used these events to determine effects of extreme winter weather on harlequin bug survival. In both years we observed nearly identical low temperatures of -15oC and this linked to high (80-96%) harlequin bug mortality. In the lab we measured exact lethal freezing temperatures in harlequin bugs (i.e. supercooling points) to see if a physiological metric could be used to predict overwinter survival. Harlequin bug adults froze and died at -10.4oC, and similarly, their larger juvenile stages freeze at -11.0oC. Freshly hatched harlequin bugs and unhatched eggs froze at considerably lower temperatures with eggs forming ice crystals at -23.2oC and recent hatches at -21.6oC. Now with an understanding of how harlequin bugs likely survive winter extreme, we can then work on developing a trap to tally their populations in the spring and predict summer and fall pest severity. In the lab and field, harlequin bug adults and large nymphs were more likely found on green and black colors, and statistically less frequently on yellow, white, purple or red colors with the exception of adult females, which were most attracted to red and green in the lab, but green and black in the field. To increase harlequin bug attraction to and termination at traps square corrugated plastic panels were wrapped with an insecticide netting and baited with harlequin bug aggregation pheromone, murgantiol. Bugs were effectively drawn to the panels, with green panels having significantly more dead harlequin bugs and fewer dead beneficial lady beetles (Coleoptera: Coccinellidae) at their base than yellow panels. Thus, green was chosen as the ideal trap color to use for another field experiment that evaluated three trap types -- a corrugated plastic square panel, pyramidal trap, and ramp trap -- each with three lure treatments, murgantiol alone or murgantiol plus a low or high rate of mustard oil. More bugs were killed with the pyramidal trap than with the panel trap or the ramp trap, and more bugs were killed at traps containing murgantiol combined with benzyl isothiocyanate than at those with murgantiol alone. This research demonstrated that with the proper visual elements and odors, harlequin bugs can be drawn to traps and effectively killed after contact with insecticide-incorporated netting. / MSLFS / Harlequin bugs are orange and black aggregation pheromone emitting stink bug pests, specifically of cole crops such as kale, broccoli and collards. This nearly loyal crop preference makes an interesting challenge for trapping them and helping farmers predict pest severity. Harlequin bugs can be found in much of North America, and are a serious problem in the southeastern United States. Presumably their persistence into northern regions is limited by extreme winters. In 2014 and 2015 the arctic polar vortex extended into mid-latitudes bringing a blanket of sustained sub-freezing temperatures to much of the United States. We used these events to determine effects of extreme winter weather on harlequin bug survival. In both years we observed nearly identical low temperatures of -15℃ and this linked to high (80-96%) harlequin bug mortality. In the lab we measured exact lethal freezing temperatures in harlequin bugs (i.e. supercooling points) to see if a physiological metric could be used to predict overwinter survival. Harlequin bug adults froze and died at -10.4℃, and similarly, their larger juvenile stages freeze at -11.0℃. Freshly hatched harlequin bugs and unhatched eggs froze at considerably lower temperatures with eggs forming ice crystals at -23.2℃ and recent hatches at -21.6℃. Now with an understanding of how harlequin bugs likely survive winter extreme, we can then work on developing a trap to tally their populations in the spring and predict summer and fall pest severity. In the lab and field, harlequin bug adults and large nymphs were more likely found on green and black colors, and statistically less frequently on yellow, white, purple or red colors with the exception of adult females, which were most attracted to red and green in the lab, but green and black in the field. To increase harlequin bug attraction to and termination at traps square corrugated plastic panels were wrapped with an insecticide netting and baited with harlequin bug aggregation pheromone, murgantiol. Bugs were effectively drawn to the panels, with green panels having significantly more dead harlequin bugs and fewer dead beneficial lady beetles (Coleoptera: Coccinellidae) at their base than yellow panels. Thus, green was chosen as the ideal trap color to use for another field experiment that evaluated three trap types – a corrugated plastic square panel, pyramidal trap, and ramp trap – each with three lure treatments, murgantiol alone or murgantiol plus a low or high rate of mustard oil. More bugs were killed with the pyramidal trap than with the panel trap or the ramp trap, and more bugs were killed at traps containing murgantiol combined with benzyl isothiocyanate than at those with murgantiol alone. This research demonstrated that with the proper visual elements and odors, harlequin bugs can be drawn to traps and effectively killed after contact with insecticide-incorporated netting.
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Ecology of the Brown Marmorated Stink Bug (Hemiptera: Pentitomidae): Oviposition on Different Trees, Nymphal Development on Various Vegetable Hosts, and Assessment of a Bacterial PathogenFormella, Adam John 07 January 2019 (has links)
The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive species that has spread throughout the United States and become a serious agricultural pest. Studies were conducted in Virginia on the survival of H. halys nymphs on different vegetable hosts and on the oviposition preference of H. halys on common tree hosts in southwestern Virginia. To determine the effects of vegetable host on H. halys survival, nymphs were placed on one of five vegetable host plants and their corresponding vegetable fruit. Survival was highest on sweet corn, followed by bell pepper and snap bean. Eggplant and tomato were poor compared to other vegetable hosts tested, potentially due to secondary compounds released by the plant to reduce feeding. Of six common host trees sampled, H. halys laid the most egg masses on catalpa, Catalpa bignonioides, while aggregation lure had no effect on the number of eggs laid. Across host trees, egg masses were more commonly found in trees with fruiting structures present. An additional study was conducted on a red-sternum phenotype of H. halys. Mortality was recorded by sternum phenotype for each sex. There was no difference in survival between groups at two time points. Biochemical tests were used to determine if the red-sternum was associated with the potentially pathogenic red bacteria Serratia marcescens. Only one stink bug's gut contents had a confirmed infection of S. marcescens. Results from these studies offer insight into H. halys development on vegetable hosts and oviposition preferences on different host trees. / MSLFS / The brown marmorated stink bug (BMSB), is an invasive insect that has spread throughout the United States and become a serious pest. Current research is focused on reducing their populations without increasing insecticide use. Studies were conducted to determine if vegetable host type influenced survival and development of this insect. Nymphs were placed on one of five vegetable plants with the corresponding vegetable fruit. Overall, survival was highest on sweet corn, followed by bell pepper and snap bean. Eggplant and tomato were poor hosts, potentially due to chemicals released by the plant to reduce insect feeding. Six common host trees of BMSB were sampled to determine where females lay the most egg masses and the effect of using an attraction lure. Catalpa trees had the most egg masses throughout the season. Use of a lure had no effect on the number of eggs laid on any tree. A red colored abdomen was observed in some adult insects throughout these studies. To determine if this was associated with higher mortality, male and female insects were observed for two weeks. There were no mortality differences at either seven or 14 days between any of the groups. Tests were used to determine if the red abdomen was caused by a red-colored bacterium. Of the insects sampled, there was only one stink bug with a confirmed infection. Results from these studies provides information that increases knowledge of this pest’s ecology in Virginia.
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Pest Management of Japanese Beetle (Coleoptera: Scarabaeidae) and a Study of Stink Bug (Hemiptera: Pentatomidae) Injury on Primocane-bearing Caneberries in Southwest VirginiaMaxey, Laura Michele 29 April 2011 (has links)
Field experiments (2007-2009) and laboratory bioassays (2009) tested the efficacy of insecticides with short pre-harvest intervals, caneberry cultivar susceptibility, and geranium toxicity for reducing Japanese beetle (JB) activity on primocane-bearing caneberries. Deltamethrin, chlorantraniliprole, bifenthrin, lime-alum, and thyme oil reduced JB activity in the field. Deltamethrin, chlorantraniliprole, acetamiprid, an azadirachtin and pyrethrin mixture, an azadirachtin and neem oil extract mixture, and an extract of Chenopodium ambrosioides reduced JB activity during the bioassays. "Prelude" had significantly more JB than "Anne", "Caroline", "Heritage", "Dinkum", or "Himbo Top" and "Prime-Jan" had significantly more JB than "Prime-Jim". Compared to certain cultivars, "Heritage", "Caroline", "Himbo Top", and "Prime-Jan" had higher percentages of injured fruit and "Autumn Bliss", "Heritage", and "Caroline" produced greater marketable and overall yields. "Prime-Jan" produced more overall yield than "Prime-Jim"; marketable yields from both blackberry cultivars were similar. Defoliation was significantly less for "Dinkum", "Caroline", "Heritage", and "Anne" than for "Prelude" in 2008 and significantly less for "Caroline" and "Anne" than "Prelude" or "Fall Gold" in 2009.
In field tests, previous consumption of geraniums lessened raspberry defoliation by JB. Bioassays indicated that JB activity was only reduced if JB were continually exposed to geranium. Therefore, the efficacy of geranium as a trap crop for JB may be limited.
The stink bug species within the caneberries were identified (2008-2009) and Euschistus servus (Say) made up 48.1 % of the overall species composition. Stink bug injury to ripening raspberries was identified as small holes between drupelets; stink bug excretions also ruined fruit. / Master of Science in Life Sciences
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Risk Assessment and Improving Brown Marmorated Stink Bug (Stål), Halyomorpha halys, Sampling in Virginia Soybean SystemsAigner, Benjamin L. 14 October 2016 (has links)
Brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), has become an important pest of soybean in the Mid-Atlantic US. To assess the influence of tree borders on BMSB infestations in soybean, twelve fields were sampled weekly using five 3-min visual counts of BMSB on tree of heaven (TOH) (Ailanthus altissima) and other host trees along a wooded border, on the adjacent soybean edge, 15 m and 30 m into the soybean field. At all locations, BMSB densities increased on TOH wooded borders in July, then, gradually moved into adjacent soybean borders later in the summer. BMSB did not move far from the field edge, with approximately half as many bugs being present at 15 m into the field and very few being detected 30 m into the field. These results validate the use of border sprays for BMSB control in soybean.
Additional studies conducted in 2013 and 2014 compared a visual plant inspection method with a standard sweep net strategy for sampling BMSB. Overall, the two methods were highly correlated with a correlation coefficient of R=0.83. Visual inspection appears to be an effective method for assessing BMSB populations in soybean.
One of the major factors affecting the distribution and establishment of invasive species is climate. The CLIMEX modeling software uses climatic and biological factors of species to predict the geographic risk for pest outbreaks. A climate simulation model was run with CLIMEX to determine the potential distribution of BMSB in Virginia based on temperature. To develop a more accurate model, factors like resource availability and source population would need to be considered. / Master of Science in Life Sciences / Brown marmorated stink bug (BMSB) is a major pest of many crops, including soybean. Before moving into soybean the bug has been observed on other preferred hosts (primarily tree of heaven) in neighboring forest edges. To determine the relationship of these hosts to BMSB and its movement into soybean fields we sampled these forest edges, the neighboring field edge, 15 m into the field, and 30 m into the field. Results showed that BMSB populations were high on the forest edges early in the season and increased rapidly on neighboring field edge when soybeans begin developing pods and seeds. Bugs rarely moved past the 15 m sample zone. These results validate the use of border sprays for BMSB control in soybean.
Sampling for BMSB with a sweep net has proven to be a challenge as the insect has a strong “startle response” where it will drop from the plant after slight disturbance. To assess the relationship between a standard sweep net sampling strategy and a new 2-min visual inspection method we sampled soybean fields in Virginia, Maryland and Delaware in 2013 and 2014. Data suggested that the 2-min visual inspection method can be used as an alternative to sweep net sampling.
Climate plays a critical role in the geographic distribution of species. We ran a climate simulation model with CLIMEX (modeling software) to determine the potential distribution of BMSB in Virginia based on temperature. To develop a more accurate model, additional factors like resource availability and distance from source population would need to be considered.
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