Stink bugs are beginning to emerge as important pests of cotton that often require management in the Lower Texas Gulf Coast. As eradication of the boll weevil progresses and producers increasingly adopt transgenic cotton varieties resulting in reduced broad spectrum pesticide use, stink bugs will likely become key cotton pests in this area. The Lower Texas Gulf Coast has a stink bug complex that differs somewhat from other areas of the Cotton Belt. Euschistus servus and lesser brown stink bugs, including E. quadrator, E. obscurus, E. crassus, and E. ictericus, make up the largest portion of this pest complex, and green/southern green stink bugs play less important roles than in other areas. Using evidence of internal feeding as a sampling criterion detected stink bug infestations more frequently that when using visual or drop cloth sampling methods. The main drawback to using this method is that species composition may still need to be determined when an economic threshold is reached in order to select the most effective control. Euschistus servus and E. quadrator both caused significant reductions in yield and fiber quality in cotton bolls, but E. servus was able to reduce yield and quality in small (1.8 cm), medium (2.8 cm), and large (3.2 cm) bolls, whereas E. quadrator reduced yield in only small bolls and reduced quality in only small and medium bolls. In general, E. servus caused more damage to bolls than E. quadrator and was able to damage a wider range of boll sizes. Dicrotophos was the most effective insecticide for stink bug control. Exposure to pyrethroids caused high mortality in N. viridula similar to that of dicrotophos, but pyrethroid activity was more variable when E. servus were exposed. In general, E. quadrator was more susceptible to insecticide treatments than E. servus, but both had similar mortalities when exposed to organophosphates, pyrethroids, and carbamates. Dynamic evidence of internal feeding thresholds may potentially be the best method for determining the need for stink bug control in cotton, but further research is necessary to refine these thresholds and make them applicable to the Lower Texas Gulf Coast.

Stink bugs are beginning to emerge as important pests of cotton that often require management in the Lower Texas Gulf Coast. As eradication of the boll weevil progresses and producers increasingly adopt transgenic cotton varieties resulting in reduced broad spectrum pesticide use, stink bugs will likely become key cotton pests in this area. The Lower Texas Gulf Coast has a stink bug complex that differs somewhat from other areas of the Cotton Belt. Euschistus servus and lesser brown stink bugs, including E. quadrator, E. obscurus, E. crassus, and E. ictericus, make up the largest portion of this pest complex, and green/southern green stink bugs play less important roles than in other areas. Using evidence of internal feeding as a sampling criterion detected stink bug infestations more frequently that when using visual or drop cloth sampling methods. The main drawback to using this method is that species composition may still need to be determined when an economic threshold is reached in order to select the most effective control. Euschistus servus and E. quadrator both caused significant reductions in yield and fiber quality in cotton bolls, but E. servus was able to reduce yield and quality in small (1.8 cm), medium (2.8 cm), and large (3.2 cm) bolls, whereas E. quadrator reduced yield in only small bolls and reduced quality in only small and medium bolls. In general, E. servus caused more damage to bolls than E. quadrator and was able to damage a wider range of boll sizes. Dicrotophos was the most effective insecticide for stink bug control. Exposure to pyrethroids caused high mortality in N. viridula similar to that of dicrotophos, but pyrethroid activity was more variable when E. servus were exposed. In general, E. quadrator was more susceptible to insecticide treatments than E. servus, but both had similar mortalities when exposed to organophosphates, pyrethroids, and carbamates. Dynamic evidence of internal feeding thresholds may potentially be the best method for determining the need for stink bug control in cotton, but further research is necessary to refine these thresholds and make them applicable to the Lower Texas Gulf Coast.

The brown stink bug, Euchistus servus (Say), is a polyphagous pest of multiple cultivated hosts in Virginia. It recently emerged as a potentially devastating pest of maize, Zea mays L. (Poaceae), in eastern Virginia where small grain (e.g., wheat, rye) production is common. In order to develop an integrated pest management (IPM) plan, research is needed to determine if brown stink bug feeding causes economic damage in maize at different growth stages and levels of infestations. Experiments were conducted in 2018 and 2019 to determine: 1) effectiveness of seed applied and in-furrow chemical control methods, 2) infestation levels in seedling and reproductive growth stages that cause economic damage, and 3) the effect, if any, of E. servus feeding on grain quality and mycotoxin contamination. Results of these experiments demonstrated that infestation levels (i.e., number of bugs divided by number of plants) of 11% and 15% in seedling and late vegetative maize, respectively, can cause measurable yield reduction at harvest. Seedling damage from E. servus is significantly mitigated by neonicotinoid seed treatments which are applied to nearly all commercial maize seed. Further, experiments indicated that maize quality can be affected by E. servus feeding in late reproductive stages of development. Results of these experiments will help to inform Virginia maize producers of the need to manage E. servus throughout the growing season. / Master of Science in Life Sciences / The brown stink bug, Euschistus servus, has emerged as a potential economic pest of maize (commonly referred to as "corn" or "field corn") in Virginia following reduced broad-spectrum insecticide use and increased adoption of no-tillage or reduced-tillage crop production systems. Stink bug infestations in maize frequently occur at two times in the growing season: following cover crop termination and following small grain harvest. We need to determine the effects of brown stink bug infestations on maize yield and quality, as well as the effectiveness of chemical management options, to help minimize yield losses and input costs for maize producers in our region. Experiments were conducted to determine: 1) the control provided by insecticidal seed treatments and in-furrow insecticide applications, 2) the level of brown stink bug infestations that cause economic damage at different growth stages of maize, and 3) the effect of brown stink bug feeding and a Fusarium fungal pathogen on grain yield and quality. Results of these experiments determined economic injury levels in seedling corn and late vegetative stages. Additionally, we found that universally applied neonicotinoid seed treatments mitigated early damage. Further, stink bug feeding through reproductive stages of development can reduce grain quality. Our results will help Virginia maize producers to make informed pest management decisions throughout the season.

<p>Examensarbetet har bestått i att konstruera en maskin åt SKF i Göteborg. Med hjälp av laserteknik skall artikelnummer och företagslogga brännas in på rullagers ytterring. Märkningen sker med hjälp av en laserenhet som levereras av ett företag som heter Servus. KSG i Surte AB står som maskinleverantör och konstruerar övrig mekanik som krävs för att maskinen skall fungera. Rullagret transporteras in i maskinen via en rullbana. Innan märkningen kan starta måste rullagret positioneras och fixeras. Detta måste ske helt automatiskt oavsett vilken rullagerdimension som lasermärkmaskinen skall hantera. Olika koncept för dessa moment har utarbetats. Koncepten har därefter utvärderats och en slutgiltig konstruktion för varje moment har bestämts. En fullständig modell av lasermärkmaskinen har därefter modellerats i Solidworks. En viktig del av detta arbete har varit att identifiera förändringsmöjligheter i nuvarande tillverkningsmetoder på KSG. De maskiner som tidigare byggts på KSG har ställt stora krav på maskinbyggaren då de ej haft tillgång till ett fullständigt tillverkningsunderlag. Lasermärkmaskinen har konstruerats i CAD-programmet Solidworks som möjliggjort att komponenter som kan laserskäras har tagits direkt ur CAD-modellen och sänts till en laserskärfirma för offertförfrågan. Det har gjort att tillverkningstiden kan förkortas och kvaliteten kan höjas. Tillverkningstiden för att bygga lasermärkmaskinen har beräknats och offerter sammanställts från samtliga leverantörer av komponenter.</p>

Examensarbetet har bestått i att konstruera en maskin åt SKF i Göteborg. Med hjälp av laserteknik skall artikelnummer och företagslogga brännas in på rullagers ytterring. Märkningen sker med hjälp av en laserenhet som levereras av ett företag som heter Servus. KSG i Surte AB står som maskinleverantör och konstruerar övrig mekanik som krävs för att maskinen skall fungera. Rullagret transporteras in i maskinen via en rullbana. Innan märkningen kan starta måste rullagret positioneras och fixeras. Detta måste ske helt automatiskt oavsett vilken rullagerdimension som lasermärkmaskinen skall hantera. Olika koncept för dessa moment har utarbetats. Koncepten har därefter utvärderats och en slutgiltig konstruktion för varje moment har bestämts. En fullständig modell av lasermärkmaskinen har därefter modellerats i Solidworks. En viktig del av detta arbete har varit att identifiera förändringsmöjligheter i nuvarande tillverkningsmetoder på KSG. De maskiner som tidigare byggts på KSG har ställt stora krav på maskinbyggaren då de ej haft tillgång till ett fullständigt tillverkningsunderlag. Lasermärkmaskinen har konstruerats i CAD-programmet Solidworks som möjliggjort att komponenter som kan laserskäras har tagits direkt ur CAD-modellen och sänts till en laserskärfirma för offertförfrågan. Det har gjort att tillverkningstiden kan förkortas och kvaliteten kan höjas. Tillverkningstiden för att bygga lasermärkmaskinen har beräknats och offerter sammanställts från samtliga leverantörer av komponenter.

La question de l’évolution des conditions serviles depuis la fin du Bas-Empire jusqu’au Xè siècle a suscité depuis la seconde moitié du XIXè siècle un foisonnement de positions contrastées tant sur les plans de l’idéologie, de la chronologie que du vocabulaire.A cet immense problème ont d’abord répondu l’école historique de la fin du XIXè siècle, puis l’apport des idées nouvelles de Marc Bloch et l’essai de synthèse de Charles Verlinden.La perspective néo-marxiste, l’école fiscaliste, les historiens allemands, de même que quelques positions isolées et régionales, comme celles de Paul Veyne, ont nourri le débat ultérieur.La présente étude s’est donc donnée pour ambition de tenter un nouvel examen d’un grand nombre de sources permettant de reconsidérer ce grand mouvement.Le mot « esclave » n’exprime pas la à lui seul la réalité de ce phénomène.Le cadre chronologique, 371-918, exprime ce paradoxe au travers de deux événements : le premier le décret de Valentinien 1er généralisant la fixation au sol des paysans d’ Illyricum, et le second la première mention du terme « sclavus » dans un diplôme de Konrad 1er en 918.Ainsi donc, jusqu’à l’avènement des carolingiens, la période romano-barbare semble maintenir une conception romaine de l’asservissement, avec toutefois l’apport des pratiques barbares et des balbutiements de l’action de l’Église.Au delà, dans un cadre politique stabilisé, les bases de la transformation vers le servage se fortifient grâce à son rôle croissant.Au Xè siècle, l’asservi est un homme différent de celui du IXè siècle. Il est devenu un paysan vivant de ses propres biens sur un sol appartenant au roi, à l’Église ou à la noblesse. / The question concerning the evolution of servile conditions from the end of the Early-Empire until the 10th century has aroused since the second half of the 19th century a proliferation of contrasting positions in terms of ideology, chronology and vocabulary.Attempts to provide an answer to this immense problem first emerged from the historical school at the end of the 19th century, followed by some new ideas contributed by Marc Bloch and summarized in an essay by Charles Verlinden.The neo-Marxist perspective, the fiscalist school, German historians, and one or two isolated and regional positions, like those of Paul Veyne, have fuelled the debate ever since.The mere term “slave” does not do justice to the reality of such a phenomenon.The chronological framework, 371-918, expresses this paradox through two events: the first, the decree by Valentinian I generalising the grounding of Illyricum peasants, and the second, the first reference to the term “sclavus‖ in a Conrad I diploma in 918.And so, up until the rise of the Carolingiens, the Romano-barbarian period would seem to maintain a Roman conception of subjugation, nourished all the same by the contribution of some Barbaric practices and the earliest signs of action on the part of the Church.Beyond this, the foundations of the transformation towards servitude are fortified thanks to the growing role of a stabilised political contextThus, in the 10th century, the subjugated man differs from his 9th century counterpart. He has become a peasant living off his own assets on a land belonging to the king, the Church or the nobility.

Stink bugs are major pests of agricultural crops throughout Virginia and much of the United States. Knowledge of the biology, the species complex, and insecticide susceptibility can improve management. A survey was conducted in Virginia to determine the species complex in soybean and cotton and to monitor for nonnative species. Seven stink bug species were identified. Acrosternum hilare (Say) and Euschistus servus (Say) were the most common. Two sampling methods, the sweep net and the beat sheet, were assessed in soybean and cotton. There was less variability with the sweep net method compared to the beat sheet method. Laboratory bioassays and field trials were conducted to evaluate the toxicity and efficacy of selected conventional and organic insecticides against A. hilare and E. servus. In bioassays with conventional insecticides, A. hilare adults and nymphs were susceptible to all pyrethroids tested. Generally, the neonicotinoids, dinotefuran and clothianidin, were more toxic to A. hilare, while thiamethoxam and acetamiprid were more toxic to E. servus. In soybean field efficacy trials, dinotefuran performed comparably to the organophosphates and pyrethroids. Laboratory bioassays with organic insecticides resulted in moderate to high levels of mortality, and in antifeedant and repellency responses. Likewise, soybean field trials indicated that a single application can reduce stink bug numbers for up to two days after treatment; however in tomato field trials multiple weekly applications did not result in significant reductions in stink bug damage. A weather model to predict abundance of A. hilare adults was developed using weekly black light trap catch data collected from 1990 to 2007 at a single location. The two weather variables that resulted in a significant model were days below freezing and mean monthly precipitation from January to April. The model was validated by correlating five independent data sets to predicted weekly trap catch. Mean trap catch plotted over time showed three peaks. In accordance with A. hilare developmental rates, the peaks indicated that two generations and a partial third occur in Virginia. Cumulative trap catch estimated from the 18-yr trap catch mean showed that 10, 50, and 90% of the total seasonal catch should occur by 153, 501, and 1066 degree days, respectively. / Ph. D.

Stink bugs, including native brown stink bug (Euschistus servus) and invasive brown marmorated stink bug (Halyomorpha halys), cause damage to a variety of crops including field corn (Zea mays). Frequency and size of stink bug infestations have increased in corn fields in the Mid-Atlantic U.S., and there are growing concerns that these infestations may contribute to reductions in grain quality including increased mycotoxin concentrations. Prior research on native and invasive stink bugs has focused on understanding their biology, the damage they cause, and elucidating effective and economic management strategies. However, few studies examined the potential for stink bugs to facilitate fungal infection and mycotoxin contamination of corn grain. Thus, the objectives of this research were to: 1) assess the relationship between invasive brown marmorated stink bug (H. halys) feeding injuries and fumonisin contamination of field corn in the Mid-Atlantic U.S., 2) determine if stink bugs are a vector for mycotoxigenic Fusarium spp. in corn, and 3) evaluate the efficacy of pesticides for mitigating stink bug feeding injury and associated mycotoxin contamination in field corn. A correlation between H. halys feeding injury and fumonisin concentrations was identified, and the ability of H. halys to increase F. verticillioides infection and fumonisin concentrations in corn was demonstrated in field experiments. Fusarium species including fumonisin-producing F. verticillioides and F. proliferatum were isolated from field-collected stink bugs, and in laboratory experiments, E. servus was able to transmit F. verticillioides to non-infected corn ears after feeding on F. verticillioides-infected corn. In field studies, both fungicide and insecticide reduced stink bug-associated mycotoxin concentrations in corn, but levels of control were inconsistent. Thus, additional tactics that target both the stink bug and Fusarium should be implemented to mitigate risks of mycotoxin contamination in corn. / Doctor of Philosophy / Native and invasive stink bugs can severely damage crops including field corn. Frequency and size of stink bug infestations in Mid-Atlantic U.S. corn fields have increased, and there is growing concern that this may contribute to reductions in grain quality. Insect feeding injury is a risk factor for fungal infection and mycotoxin contamination in corn. Mycotoxins are toxic chemicals produced by certain fungi that have detrimental health effects on animals including livestock and humans. The relationship between stink bug feeding injuries and mycotoxin contamination in corn grain is not well understood, and management strategies to minimize the risk of mycotoxin contamination in corn need to be identified. The main goal of this research was to characterize interactions between stink bugs and mycotoxin-producing fungi and identify tactics for controlling both the insect pest and pathogen. Specific objectives were to: 1) assess the relationship between invasive brown marmorated stink bug (H. halys) feeding injuries and fumonisin contamination of field corn in the Mid-Atlantic U.S., 2) determine if stink bugs are a vector for mycotoxin-producing Fusarium spp. in corn, and 3) evaluate the efficacy of pesticides for mitigating stink bug feeding injury and associated mycotoxin contamination in field corn. Results from this work indicated that stink bugs have the ability to cause feeding injuries which facilitate invasion of mycotoxin-producing Fusarium species, leading to increases in mycotoxin concentrations in corn grain. Studies also demonstrated that stink bugs can vector Fusarium species during feeding and increase Fusarium infection of corn resulting in subsequent mycotoxin contamination. Field studies indicated that pesticide applications targeting both the stink bugs and mycotoxigenic fungi may be needed to minimize risk of mycotoxin contamination in corn. However, under low pest pressure, application of pesticides is unlikely to be profitable.

No description available.