• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 4
  • 4
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 26
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Organotypic human skin disease models for the assessment of novel therapeutic approaches

Fell, Benjamin January 2017 (has links)
Comprehensive in vitro modelling of inflammatory human skin conditions is an essential first step in the development and assessment of potential therapeutic approaches. Mouse models or monolayer keratinocyte cultures come with distinct limitations which might be complimented or overcome by the use of human-specific organotypic 3D culture models. Over the course of this thesis, an organotypic culture system, based on patientderived immortalised keratinocyte cell lines on a dermal equivalent collagen 1 gel, was established and used to recapitulate phenotypical features for two hereditary skin diseases, Harlequin ichthyosis and Tylosis with oesophageal cancer. Small molecular compounds, supplied via the medium, or RNA interference were used to modulate disease-specific changes in histology and marker expression of the skin equivalent. Since hyperproliferative skin conditions can be associated with an aberrant wound healing phenotype, the organotypic system was manipulated to obtain a basic in vitro wound healing model. This model displays typical features of re-epithelialisation over time (both normal and disease-specific) which can further be manipulated via shRNAmediated knockdown or the exogenous supply of compounds. In parallel, a non-disease model was used to assess the topical application of novel nanopolymeric drug delivery systems in regard to their ability to penetrate across the permeability barrier. Penetrance profiles for the organotypic model (in dependence of co-application with chemical enhancers) showed a similar pattern as for topical applications performed in parallel on explant skin. In conclusion, a highly adaptable human organotypic keratinocyte culture model was developed and used to recapitulate (and manipulate) skin disease phenotypes and epidermal wound healing in vitro, as well as perform first essential assessments of novel drug delivery systems.
12

Role of trap crops on harlequin bug, Murgantia histrionica (Hahn), population dynamics and parasitism in broccoli plots

Ludwig, Scott W. 02 May 2009 (has links)
Trap crops were evaluated for harlequin bug control in broccoli field plots in 1994 and 1995. Mustard and rape prevented low densities of harlequin bug from reaching broccoli, but at high densities the insect moved from the trap plants into the broccoli. This indicates that harlequin bugs that are attracted to trap plants may damage the protected broccoli if their numbers are not prevented from increasing. Harlequin bugs were shown to have two and a partial third generation a year. Trissolcus murgantiae Ashmead and Ooencyrtus johnsoni Howard, were identified as egg parasitoids. Their combined parasitization levels for the two years were 8% and 37%. T. murgantiae accounted for 87% and 96% of the parasitization, respectively.. When 19.6 cm and 11.9 cm broccoli plants were exposed to five densities of harlequin bug adults a negative correlation between plant mortality and insect density was observed (y = 38.00 - 2.32x, r2 = 0.95 and y = 22.17 - 1.17x, r2 = 0.99, respectively). No correlation was observed in broccoli plants 11.9 tall.. Host plants affected harlequin bug development. Nymphs developed faster when reared on rape in comparison with mustard. The preoviposition time for rape reared nymphs was shorter than mustard reared insects. Fecundity and viability of eggs were not different for harlequin bugs reared at different sex ratios. / Master of Science
13

The Harlequin ladybeetle Harmonia axyridis (Coleoptera: Coccinellidae) in the Western Cape Province, South Africa: effects on arthropods in urban, agricultural and natural ecosystems

Mukwevho, Vuledzani Oral 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Invasive arthropod predators are one of the largest and most diverse groups of invasive insects in the world. Many are generalist predators, with cosmopolitan distributions due to their use as biological control agents in agriculture. Harmonia axyridis (Coleoptera: Coccinellidae), an invasive arthropod predator species native to Asia, which now has a world-wide distribution. It is considered one of the most successful biological control predator species and is generally considered to be economically beneficial. However, negative effects have recently emerged in agricultural and natural systems. Harmonia axyridis poses a threat to biodiversity as it outcompetes native species for food resources. It can also feed directly on native predatory arthropods that disrupt natural ecosystem processes. Their movement in-and-out of agricultural landscapes may depend on food availability with natural vegetation alongside agricultural areas often utilised for refuge and alternative food resources. This beetle has also been recorded in urban areas. The aim of this study was to determine how the invasive H. axyridis beetle uses the local landscape in the Western Cape province, South Africa, and to determine its threat to native species. I sampled urban landscapes, vineyards, natural vegetation/vineyard edge zones and pristine natural areas for arthropods every second month using a suction sampler. Data collected included the abundance and diversity of H. axyridis, herbivores, local predators and non-Harmonia ladybeetles. Most H. axyridis were collected in urban areas during all sampling periods. Highest abundance was recorded in May and July (winter). This indicates that urban areas were the preferred landscape feature and that these act as ovipositing areas, particularly as larval H. axyridis were also only collected in urban areas. Significantly, vineyards and natural vegetation had very low abundance of H. axyridis, questioning their value as a biological control agent in this region. Harmonia axyridis had a negative effect on the overall local arthropod community, as well as the predator and herbivore guilds, although it was positively correlated with the abundance of non-Harmonia ladybeetles. This suggests that H. axyridis and non-Harmonia ladybeetles are responding to the same resources in these landscapes. A negative correlation found between H. axyridis and the abundance of predators is most likely due to competition for the same resources (e.g. prey items). These negative impacts, along with their negligible value as biological control agents in agriculture, suggest that a programme should be implemented to control this invasive species. More specifically, control should be aimed in urban areas during winter when and where the species aggregates and when larvae are present. / AFRIKAANSE OPSOMMING: Geleedpotige roofdiere is een van die grootste en mees diverse groepe van uitheemse insekte in die wêreld. Die meeste is veelsydige roofdiere, met wêreldwye verspreiding te danke aan hul gebruik as biologiese beheer agente in landbou gebiede. Byvoorbeeld, Harmonia axyridis (Coleoptera: Coccinellidae), 'n indringer geleedpotige roofdier spesies inheems aan Asië, het nou 'n wêreldwye verspreiding. Dit word beskou as die mees suksesvolle roofdier spesies wat gebruik word vir biologiese beheer en word oor die algemeen beskou as ekonomies voordelig. Negatiewe effekte was onlangs aangeteken beide in landbou gebiede en natuurlike areas. Harmonia axyridis hou 'n bedreiging in vir inheemse biodiversiteit as dit inheemse spesies uitkompeteer vir voedsel bronne. Dit kan ook direk voed op plaaslike roofsugtige geleedpotiges wat trofiese vlakke ontwrig en uiteindelik, biodiversiteit. Hulle beweging in-en-uit landbou landskappe kan gekoppel word aan die beskikbaarheid van voedsel, en gebruik natuurlike plantegroei langs landbou gebiede dikwels as 'n toevlugs oord en area vir alternatiewe voedsel bronne. Harmonia axyridis word ook in stedelike gebiede aangeteken. Die doel van hierdie studie was om te bepaal hoe die indringer Harlekynkewer die plaaslike landskap gebruik met die fokus op wingerde in die Wes-Kaap provinsie van Suid-Afrika, en tweedens om die bedreiging wat hierdie kewer moontlik vir inheemse spesies te bepaal. Ek het arthropoda in stedelike landskappe, wingerde, natuurlike plantegroei / wingerd rand sones en ongerepte natuurlike areas elke twee maande met behulp van 'n D-vac versamel. Monsters was ontleed deur gebruik te maak van die getalle van H. axyridis, herbivore, plaaslike roofdiere en nie-Harmonia liewenheers kewers. Die meeste H. axyridis was in stedelike gebiede versamel gedurende al die seisoene, maar meeste individue was gedurende Mei en Julie (winter) versamel. Hierdie toon dat stedelike gebiede die voorkeur-landskappe is vir hierdie kewers en dat hierdie gebiede opgetree as eierleggende gebiede, veral omdat larwes van H. axyridis slegs in hierdie gebiede aangeteken was. Wingerde en die natuurlike plantegroei het baie lae getalle H. axyridis gehuisves wat hul waarde as biobeheermiddel bevraagteken. Harmonia axyridis het 'n negatiewe uitwerking op die algehele plaaslike geleedpotige gemeenskappe gehad, asook op die die roofdier en herbivoor gildes, maar hul getalle was positief gekorreleer met die getalle van nie-Harmonia liewenheerskewers. Dit dui daarop dat H. axyridis en nie-Harmonia liewenheerskewers beide reageer op dieselfde hulpbronne in hierdie landskappe. 'n Negatiewe korrelasie was gevind tussen die getalle van H. axyridis en die getalle van ander predatoriese geleedpotiges at waarskynlik te danke was aan mededinging tussen hierdie groepe vir dieselfde hulpbronne (bv prooi). Hierdie negatiewe invloede, asook hul verminderde waarde as biobeheeragente in die landbou, dui daarop dat 'n program in werking gestel moet word om hierdie indringerspesies te beheer. Meer spesifiek, beheer moet gedurende die winter en in stedelike gebiede geskied, waar en wanneer hierdie spesie op sy volopste is en waar larwes teenwoordig is.
14

The spread of the harlequin ladybird Harmonia axyridis (Coleoptera: coccinellidae) in Europe and its effects on native ladybirds

Brown, Peter M. J. January 2010 (has links)
Native to Asia, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an invasive non-native ladybird in Europe and North America, where it was widely introduced as a biological control agent of aphids and coccids. There were three main objectives of this study: firstly, to investigate the spread and distribution of H. axyridis in Europe from the start of the invasion process; secondly, to study its ecology in Great Britain; and thirdly, to examine its effects on native ladybirds in Britain. In Europe, collaborations with a network of scientists allowed the collation of H. axyridis occurrence data from across the continent. In Great Britain, a web-based public survey (www.harlequin-survey.org) was used, leading to the receipt of over 10,000 verified records of H. axyridis between 2004 and 2008. National land cover data enabled the habitats used by H. axyridis to be identified across Great Britain. These datasets were analysed in order to study the spread and ecology of H. axyridis in Europe and Britain. Fieldwork over a three year period (2006 to 2008) was carried out to examine changes in ladybird species assemblages during the invasion phase of H. axyridis in eastern England. Laboratory work was conducted to detect intraguild predation by H. axyridis, through PCR analyses of gut contents of field-collected ladybirds. In Europe, H. axyridis has spread since 2001 at the rate of approximately 200km yr-1. It has become established in at least 23 European countries. The established range extends from Norway in the north to southern France in the south, and from Ukraine in the east to Great Britain in the west. In the first five years of establishment H. axyridis spread north through Britain at the rate of 105km yr-1 and west at the rate of 145km yr-1. Evidence of the production of two generations per year was found, giving H. axyridis an advantage over most native ladybirds in Britain. Although H. axyridis was very common in urban habitats, it increasingly used semi-natural habitats. In addition, whilst the species was most common on deciduous trees, it was increasingly found on herbaceous plants. Aceraceae, Rosaceae and Malvaceae were the dominant plant families used by H. axyridis, especially for breeding. In eastern England H. axyridis increased from 0.1% to 40% of total ladybirds in three years, whilst native aphidophagous ladybirds declined from 84% to 41% of total ladybirds in the same period. Three species in particular experienced declines: Adalia 2-punctata, Coccinella 7-punctata and Propylea 14-punctata. Harmonia axyridis was the most abundant species by the end of the study. Detection of intraguild predation by one coccinellid on another, in the field in Europe, was shown for the first time using PCR techniques: A. 2-punctata DNA was detected in the gut of one of 112 field-collected H. axyridis. Harmonia axyridis has spread very quickly since 2001 and has become one of the most widely distributed coccinellids in Europe. Populations of native aphidophagous ladybirds were negatively affected by the arrival of H. axyridis, partly through intraguild predation.
15

UPDATED MOLECULAR GENETICS AND PATHOGENESIS OF ICHTHYOSES

AKIYAMA, MASASHI 08 1900 (has links)
No description available.
16

Arlequimia mariodeandradeana

Postal, Ricardo January 2007 (has links)
O presente trabalho é uma interpretação crítica da prática artística de Mário de Andrade que interroga como a apropriação da figura do Arlequim, que atravessa sua obra, é transformada numa proposta estética e numa conformação de artista. É realizado um panorama histórico da formação da Commedia dell’arte e conceitualiazam-se suas principais máscaras e personagens. Centra-se então a atenção na figura do Arlequim para analisar, a partir de suas fontes folclóricas, ritualísticas e iconográficas como ela ganha características diabólicas, animalescas e intermediárias entre mundos diversos (o selvagem e o urbano, o além e o terreno, etc.) Estuda-se a escolha de Mário de Andrade por essa “máscara” e do que ela significa no contexto da recorrência do fenômeno do “artista enquanto saltimbanco” na arte européia, acompanhando sua intensificação nas vanguardas (cubo e futurismo bem como no movimento Dada). Olhando para o modo como a crítica percebeu o Arlequim dentro da escrita de Mário de Andrade, dialogamos com esses aspectos e propomos uma ampliação do significado dessa figura, vendo-a como fundamento do ato improvisado de escrever e representar uma arte e uma identidade cuja totalidade seria impossível ainda no Brasil. Parte-se para a análise específica de Macunaíma, obra cuja feição rapsódica indica já a proximidade com o improvisar de várias fontes símile à prática arlequinal da Commedia dell’arte. Além do aspecto da narrativa, se elencam outros elementos que aproximam o herói indígena do trabalhador braçal italiano, principalmente o caráter intermediário do ser diabólico que atravessa mundos, conectando duas realidades diversas. É ressaltado o traço do embate entre a nova e a velha geração, presente tanto nas apresentações da Commedia dell’arte, na prática dos charivari, bem como na criação de Macunaíma. Abordada através de uma perspectiva da crítica do imaginário, a obra pretende ser compreendida como um conjunto de imagens que gera uma figura central, a guiar a poética do artista, simbolizando nela a simbiose que Mário de Andrade propõe entre estética, práxis e vida. / This paper is a critical interpretation of Mario de Andrade’s artistic practice and interrogates how the appropriation of the Harlequin character throughout his work is transformed into an aesthetic proposal and in a conformation of the artist. A historical overview of the Commedia dell’arte formation process and a conceptualization of its main masks and characters are also carried out in order to understand the nature and origin of the Harlequin mask. The attention is then focused on the Harlequin character in order to analyze, from its iconographic, ritualistic and folkloric sources, how it gains animal, evil characteristics in between diverse worlds (the savage and the urban, the earthy and the spiritual, etc.) A study is carried out of Mario de Andrade’s choice for this mask and its meaning in the context of the recurrence of the phenomenon of the “artists as a street entertainer [saltimbanco]” within European art, following its intensification in the Vanguard movements (Cubism, Futurism and Dada). Looking at the way critics perceived the Harlequin in Mario de Andrade’s writings, we dialogue with those perceptions and propose a stretching of the character’s meaning, seeing it as the basis for the improvised act of writing and representing an art and an identity which would not still be possible in Brazil. From that point on we make a specific analysis of Macunaíma, a rhapsodic work that indicates the proximity with the improvising in many sources similar to the Harlequin practice in Comedia dell’arte. Besides the narrative aspects, some other elements bring the indigenous character close to the Italian laborer, specially the intermediary character of the evil being who crosses worlds, connecting two diverse realities. We discuss the confrontation between the old and the new generation seen in the performances of Comedia dell’arte, the practices of the charivari, as well as in the creation of Macunaíma. Approached through a critical perspective of the imaginary, the work is intended as a set of images that generates a central figure orienting the artist’s poetics, symbolizing in it the symbiosis between aesthetic, praxis and life proposed by Mario de Andrade.
17

Arlequimia mariodeandradeana

Postal, Ricardo January 2007 (has links)
O presente trabalho é uma interpretação crítica da prática artística de Mário de Andrade que interroga como a apropriação da figura do Arlequim, que atravessa sua obra, é transformada numa proposta estética e numa conformação de artista. É realizado um panorama histórico da formação da Commedia dell’arte e conceitualiazam-se suas principais máscaras e personagens. Centra-se então a atenção na figura do Arlequim para analisar, a partir de suas fontes folclóricas, ritualísticas e iconográficas como ela ganha características diabólicas, animalescas e intermediárias entre mundos diversos (o selvagem e o urbano, o além e o terreno, etc.) Estuda-se a escolha de Mário de Andrade por essa “máscara” e do que ela significa no contexto da recorrência do fenômeno do “artista enquanto saltimbanco” na arte européia, acompanhando sua intensificação nas vanguardas (cubo e futurismo bem como no movimento Dada). Olhando para o modo como a crítica percebeu o Arlequim dentro da escrita de Mário de Andrade, dialogamos com esses aspectos e propomos uma ampliação do significado dessa figura, vendo-a como fundamento do ato improvisado de escrever e representar uma arte e uma identidade cuja totalidade seria impossível ainda no Brasil. Parte-se para a análise específica de Macunaíma, obra cuja feição rapsódica indica já a proximidade com o improvisar de várias fontes símile à prática arlequinal da Commedia dell’arte. Além do aspecto da narrativa, se elencam outros elementos que aproximam o herói indígena do trabalhador braçal italiano, principalmente o caráter intermediário do ser diabólico que atravessa mundos, conectando duas realidades diversas. É ressaltado o traço do embate entre a nova e a velha geração, presente tanto nas apresentações da Commedia dell’arte, na prática dos charivari, bem como na criação de Macunaíma. Abordada através de uma perspectiva da crítica do imaginário, a obra pretende ser compreendida como um conjunto de imagens que gera uma figura central, a guiar a poética do artista, simbolizando nela a simbiose que Mário de Andrade propõe entre estética, práxis e vida. / This paper is a critical interpretation of Mario de Andrade’s artistic practice and interrogates how the appropriation of the Harlequin character throughout his work is transformed into an aesthetic proposal and in a conformation of the artist. A historical overview of the Commedia dell’arte formation process and a conceptualization of its main masks and characters are also carried out in order to understand the nature and origin of the Harlequin mask. The attention is then focused on the Harlequin character in order to analyze, from its iconographic, ritualistic and folkloric sources, how it gains animal, evil characteristics in between diverse worlds (the savage and the urban, the earthy and the spiritual, etc.) A study is carried out of Mario de Andrade’s choice for this mask and its meaning in the context of the recurrence of the phenomenon of the “artists as a street entertainer [saltimbanco]” within European art, following its intensification in the Vanguard movements (Cubism, Futurism and Dada). Looking at the way critics perceived the Harlequin in Mario de Andrade’s writings, we dialogue with those perceptions and propose a stretching of the character’s meaning, seeing it as the basis for the improvised act of writing and representing an art and an identity which would not still be possible in Brazil. From that point on we make a specific analysis of Macunaíma, a rhapsodic work that indicates the proximity with the improvising in many sources similar to the Harlequin practice in Comedia dell’arte. Besides the narrative aspects, some other elements bring the indigenous character close to the Italian laborer, specially the intermediary character of the evil being who crosses worlds, connecting two diverse realities. We discuss the confrontation between the old and the new generation seen in the performances of Comedia dell’arte, the practices of the charivari, as well as in the creation of Macunaíma. Approached through a critical perspective of the imaginary, the work is intended as a set of images that generates a central figure orienting the artist’s poetics, symbolizing in it the symbiosis between aesthetic, praxis and life proposed by Mario de Andrade.
18

Arlequimia mariodeandradeana

Postal, Ricardo January 2007 (has links)
O presente trabalho é uma interpretação crítica da prática artística de Mário de Andrade que interroga como a apropriação da figura do Arlequim, que atravessa sua obra, é transformada numa proposta estética e numa conformação de artista. É realizado um panorama histórico da formação da Commedia dell’arte e conceitualiazam-se suas principais máscaras e personagens. Centra-se então a atenção na figura do Arlequim para analisar, a partir de suas fontes folclóricas, ritualísticas e iconográficas como ela ganha características diabólicas, animalescas e intermediárias entre mundos diversos (o selvagem e o urbano, o além e o terreno, etc.) Estuda-se a escolha de Mário de Andrade por essa “máscara” e do que ela significa no contexto da recorrência do fenômeno do “artista enquanto saltimbanco” na arte européia, acompanhando sua intensificação nas vanguardas (cubo e futurismo bem como no movimento Dada). Olhando para o modo como a crítica percebeu o Arlequim dentro da escrita de Mário de Andrade, dialogamos com esses aspectos e propomos uma ampliação do significado dessa figura, vendo-a como fundamento do ato improvisado de escrever e representar uma arte e uma identidade cuja totalidade seria impossível ainda no Brasil. Parte-se para a análise específica de Macunaíma, obra cuja feição rapsódica indica já a proximidade com o improvisar de várias fontes símile à prática arlequinal da Commedia dell’arte. Além do aspecto da narrativa, se elencam outros elementos que aproximam o herói indígena do trabalhador braçal italiano, principalmente o caráter intermediário do ser diabólico que atravessa mundos, conectando duas realidades diversas. É ressaltado o traço do embate entre a nova e a velha geração, presente tanto nas apresentações da Commedia dell’arte, na prática dos charivari, bem como na criação de Macunaíma. Abordada através de uma perspectiva da crítica do imaginário, a obra pretende ser compreendida como um conjunto de imagens que gera uma figura central, a guiar a poética do artista, simbolizando nela a simbiose que Mário de Andrade propõe entre estética, práxis e vida. / This paper is a critical interpretation of Mario de Andrade’s artistic practice and interrogates how the appropriation of the Harlequin character throughout his work is transformed into an aesthetic proposal and in a conformation of the artist. A historical overview of the Commedia dell’arte formation process and a conceptualization of its main masks and characters are also carried out in order to understand the nature and origin of the Harlequin mask. The attention is then focused on the Harlequin character in order to analyze, from its iconographic, ritualistic and folkloric sources, how it gains animal, evil characteristics in between diverse worlds (the savage and the urban, the earthy and the spiritual, etc.) A study is carried out of Mario de Andrade’s choice for this mask and its meaning in the context of the recurrence of the phenomenon of the “artists as a street entertainer [saltimbanco]” within European art, following its intensification in the Vanguard movements (Cubism, Futurism and Dada). Looking at the way critics perceived the Harlequin in Mario de Andrade’s writings, we dialogue with those perceptions and propose a stretching of the character’s meaning, seeing it as the basis for the improvised act of writing and representing an art and an identity which would not still be possible in Brazil. From that point on we make a specific analysis of Macunaíma, a rhapsodic work that indicates the proximity with the improvising in many sources similar to the Harlequin practice in Comedia dell’arte. Besides the narrative aspects, some other elements bring the indigenous character close to the Italian laborer, specially the intermediary character of the evil being who crosses worlds, connecting two diverse realities. We discuss the confrontation between the old and the new generation seen in the performances of Comedia dell’arte, the practices of the charivari, as well as in the creation of Macunaíma. Approached through a critical perspective of the imaginary, the work is intended as a set of images that generates a central figure orienting the artist’s poetics, symbolizing in it the symbiosis between aesthetic, praxis and life proposed by Mario de Andrade.
19

Investigating host plant selection of harlequin bug, Murgantia histrionica (Hahn), in order to improve a trap cropping system for its management

Wallingford, Anna Kate 04 May 2012 (has links)
Harlequin bug (HB), Murgantia histrionica (Hahn), is a pest of cole crops. Alternative control strategies were investigated for control of HB, including trap cropping and systemic neonicotinoid insecticide applications. Potential trap crops, mustard (Brassica juncea "Southern Giant Curled" ), rapeseed (B. napus "Athena"), rapini (B. rapa) and arugula (Eruca sativa) were preferred over collard (B. oleracea "Champion"), and a non-brassica control, bean (Phaseolus vulgaris "Bronco") in field-cage choice tests. Harlequin bug could not complete development on bean, developed poorly on arugula but was found to complete development on mustard, collard, rapeseed and rapini. In the field, mustard was found to be an effective trap crop for reducing HB feeding injury on collard at three experimental sites in 2010 and 2011. Augmentation of the mustard trap crop with a systemic, neonicotinoid insecticide did not increase the level of control of harlequin bug for the duration of the ten week growing period. In olfactometer choice tests, male HB responded to plant volatiles of bean, collard and mustard, but preferred Brassica volatiles over those from bean. Female response to plant volatiles alone was weak and inconsistent. Both males and females preferred volatiles from other males feeding on Brassica host plant over plant volatiles alone, and were deterred by volatiles from males feeding on bean versus the plant alone. Laboratory toxicity assays revealed that the neonicotinoid insecticides imidacloprid, thiamethoxam, dinotefuran, and clothianidin were toxic to HB nymphs; LC50 = 0.57, 0.52, 0.39, and 0.39 mg ai/liter, respectively. Field experiments were conducted to evaluate the efficacy of these insecticides over time when applied as a one-time drench, and all were found to provide significantly higher mortality of HB for at least 14 days after application. / Ph. D.
20

Murgantia histrionica (Hahn): new trapping tactics and insights on overwintering survival

DiMeglio, 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.

Page generated in 0.0365 seconds