Typescript. / Thesis (Ph. D.)--University of Hawaii, 1966. / Bibliography: leaves 101-105. / vi, 105 l mounted illus., tables

Thesis (MSc)--Stellenbosch University, 1992. / One copy microfiche. / ENGLISH ABSTRACT: The effects of synthetic pyrethroids on the spider mite, Tetranychus urticae Koch, and its natural enemies was investigated. The pyrethroid cyfluthrin, sprayed for the control of fruit weevil Phlyctinus callosus, did not cause mite outbreaks and was not harmful to the predators when sprayed before they appeared on the apple trees. This spray also gave good control of thrips, bollworm (Heliothis armigera) and fruit weevil (P. callosus). A late season spray of deltamethrin against codling moth, caused an increase in the phytophagous mite population. This was assosiated with a temporary reduction in the population level of the predatory beetle, Oligota fageli. The plants found on the orchard floor were examined. The plant diversity was low and plants that acted as hosts of phytophagous mites during the winter were scarce. However, Solanum nigum carried high mite populations and infected the adjacent apple trees. The plants were too few to have an effect on the whole orchard. Eight synthetic pyrethroids were tested for repellency in a leafdisk dip and spray bioassay using T. urticae. Deltamethrin and fenvalerate caused no walk-off. Cyfluthrin and fluvalinate caused moderate walk-off and bifenthrin, cyhalothrin and lambda-cyhalothrin caused high walk-off. / AFRIKAANSE OPSOMMING: Die invloed van sintetiese piretroIedes op die rooispinmyt, Tetranychus urticae Koch en hul natuurlike vyande is ondersoek. Die piretroIed, cyfluthrin, gespuit vir die beheer van snuitkewer, P4ctinus callosus, het the mytuitbrake veroorsaak the en was ook the skadelik vir predatore nadat dit vroeg in die seisoen, voordat myte in die appelbome verskyn het, gespuit is the. Die bespuiting het ook goeie beheer van blaaspootjies, bolwurm (Heliothis amdgera) en P. callosus gegee. Deltametrien wat later in die seisoen toegedien is vir die beheer van kodlingmot, Cydia pomonella, het 'n mytuitbraak veroorsaak. Dit word geassossieer met die tydelike onderdrukking van die populasievlak van die predatoriese kewer, Oligota fageli. Die plante in die dekgewas is ondersoek. Die plant-verskeidenheid was laag en plante wat kon dien as oorwinterings gashere vir fitofage myte kon dien was skaars. Solanum nigrum het egter groot bevolkings myte gedra wat die appelbome naaste aan hulle eerste besmet het. Daar was egter te min van hierdie plante om 'n invloed op die hele boord te he. Agt piretroIedes is vir afwering van T. urticae in 'n blaarskyf doop en spuit bioessal getoets. Deltamethrin en fenvalerate het geen afwering getoon the. Cyfluthrin en fluvalinate het 'n redelike afwering, terwyl bifenthrin, cyhalothrin en lamda-cyhalothrin het 'n hod mate van afwering getoon

No description available.

Made available in DSpace on 2014-06-11T19:25:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-07Bitstream added on 2014-06-13T19:52:53Z : No. of bitstreams: 1 azevedo_lh_me_jabo.pdf: 773136 bytes, checksum: 2665952a5393ef93ef3a9d7e76de461d (MD5) / A cultura da lichia (Litchi chinensis Sonn.) pode ser severamente danificada pelo ácaro Aceria litchii (Keifer), a principal praga desta cultura no Brasil. Produtores brasileiros de lichia estão preocupados com o severo dano causado por esse ácaro, dadas as poucas opções disponíveis para o seu controle. O objetivo deste trabalho foi determinar aspectos que poderiam levar ao controle efetivo de A. litchii no Brasil, causando o menor impacto ambiental possível. O trabalho compreendeu atividades de campo e de laboratório. O primeiro estudo se referiu a uma avaliação da dinâmica populacional do ácaro. Este foi realizado durante um ano. Aceria litchii permaneceu em plantas de lichia ao longo do ano, atingindo os níveis mais elevados em novembro de 2011 e junho de 2012. O principal predador a este associado foi Phytoseius intermedius. Este predador e outros da mesma família não foram capazes de evitar os danos causados pela praga, o que não significa que os danos não pudessem ser ainda maiores na ausência destes predadores. O segundo estudo correspondeu à determinação de parâmetros biológicos do predador quando alimentado com A. litchii. Phytoseius intermedius foi capaz de completar seu desenvolvimento e se reproduzir com sucesso alimentando-se desta presa. O terceiro estudo correspondeu a uma avaliação de laboratório do efeito de 11 pesticidas sobre A. litchii e P. intermedius, usando uma torre de Potter. O quarto estudo foi uma continuação do terceiro, avaliando em condição de campo os pesticidas que produziram os melhores resultados no estudo anterior. Enxofre, fenpiroximato e hexitiazoxi mostraram-se os mais eficientes contra A. litchii, enquanto azadiractina, seguida por fenpiroximato e hexitiazoxi, foram os mais seletivos para o predador. Os resultados obtidos são considerados importantes para o estabelecimento de um programa de manejo de A. litchii no Estado de São Paulo. / Litchi crop (Litchi chinensis Sonn.) can be severely damaged by the mite Aceria litchii (Keifer), the major pest of this crop in Brazil. Brazilian litchi growers are currently worried with the high damage caused by this mite, given the limitations of options available for its control. The objective of this work was to determine aspects that could lead to the effective control A. litchii in Brazil, causing as little environmental impact as possible. The work comprised of field and laboratory observations. The first study referred to an evaluation of the mite population dynamics. It was conducted during one year. Aceria litchii remained on litchi plants throughout the year, reaching the highest levels in November 2011 and June 2012. The main predator associated with it was Phytoseius intermedius. This predator and other predators of the same family were not able to prevent damage by the pest, what does not mean that the damage could have been still higher in the absent of those predators. The second study corresponded to the determination of biological parameters of this predator when feeding on A. litchii. It was able to complete its development and reproduce successfully on that prey. The third study corresponded to a laboratory evaluation on the effect of 11 pesticides on A. litchii and P. intermedius, using a Potter tower. The fourth study was a continuation of the third, trying under field condition the pesticides that produced the best results in the previous study . Sulfur, fenpyroximate and hexythiazox were shown as most effective against A. litchii, whereas azadirachtin, followed by fenpyroximate and hexythiazox were the most selective for the predator. The results obtained are considered important for the establishment of a management program of A. litchii in São Paulo state.

Orientador: Gilberto Joséde Moraes / Coorientador: Pedro Takao Yamamoto / Banca: Antonio Carlos Lofego / Banca: Daniel Júnior de Andrade / Resumo: A cultura da lichia (Litchi chinensis Sonn.) pode ser severamente danificada pelo ácaro Aceria litchii (Keifer), a principal praga desta cultura no Brasil. Produtores brasileiros de lichia estão preocupados com o severo dano causado por esse ácaro, dadas as poucas opções disponíveis para o seu controle. O objetivo deste trabalho foi determinar aspectos que poderiam levar ao controle efetivo de A. litchii no Brasil, causando o menor impacto ambiental possível. O trabalho compreendeu atividades de campo e de laboratório. O primeiro estudo se referiu a uma avaliação da dinâmica populacional do ácaro. Este foi realizado durante um ano. Aceria litchii permaneceu em plantas de lichia ao longo do ano, atingindo os níveis mais elevados em novembro de 2011 e junho de 2012. O principal predador a este associado foi Phytoseius intermedius. Este predador e outros da mesma família não foram capazes de evitar os danos causados pela praga, o que não significa que os danos não pudessem ser ainda maiores na ausência destes predadores. O segundo estudo correspondeu à determinação de parâmetros biológicos do predador quando alimentado com A. litchii. Phytoseius intermedius foi capaz de completar seu desenvolvimento e se reproduzir com sucesso alimentando-se desta presa. O terceiro estudo correspondeu a uma avaliação de laboratório do efeito de 11 pesticidas sobre A. litchii e P. intermedius, usando uma torre de Potter. O quarto estudo foi uma continuação do terceiro, avaliando em condição de campo os pesticidas que produziram os melhores resultados no estudo anterior. Enxofre, fenpiroximato e hexitiazoxi mostraram-se os mais eficientes contra A. litchii, enquanto azadiractina, seguida por fenpiroximato e hexitiazoxi, foram os mais seletivos para o predador. Os resultados obtidos são considerados importantes para o estabelecimento de um programa de manejo de A. litchii no Estado de São Paulo. / Abstract: Litchi crop (Litchi chinensis Sonn.) can be severely damaged by the mite Aceria litchii (Keifer), the major pest of this crop in Brazil. Brazilian litchi growers are currently worried with the high damage caused by this mite, given the limitations of options available for its control. The objective of this work was to determine aspects that could lead to the effective control A. litchii in Brazil, causing as little environmental impact as possible. The work comprised of field and laboratory observations. The first study referred to an evaluation of the mite population dynamics. It was conducted during one year. Aceria litchii remained on litchi plants throughout the year, reaching the highest levels in November 2011 and June 2012. The main predator associated with it was Phytoseius intermedius. This predator and other predators of the same family were not able to prevent damage by the pest, what does not mean that the damage could have been still higher in the absent of those predators. The second study corresponded to the determination of biological parameters of this predator when feeding on A. litchii. It was able to complete its development and reproduce successfully on that prey. The third study corresponded to a laboratory evaluation on the effect of 11 pesticides on A. litchii and P. intermedius, using a Potter tower. The fourth study was a continuation of the third, trying under field condition the pesticides that produced the best results in the previous study . Sulfur, fenpyroximate and hexythiazox were shown as most effective against A. litchii, whereas azadirachtin, followed by fenpyroximate and hexythiazox were the most selective for the predator. The results obtained are considered important for the establishment of a management program of A. litchii in São Paulo state. / Mestre

Historically, most twospotted spider mite, Tetranychus urticae Koch, infestations occurred during the late season near maturity, but since 2005, infestations of cotton have become more common throughout the entire season. Several factors may have contributed to the increasing frequency of mites in seedling cotton, one of which is a shift in production practices from furrow applied aldicarb to neonicotinoid seed treatments for thrips control. Another factor that may impact T. urticae densities in seedling cotton is a shift from pre-plant tillage to conservation tillage or no-till cropping systems. Although the literature confirms that T. urticae can cause extensive cotton yield losses, there is a need to further refine potential late-season yield loss. From 2007 to 2009 a series of experiments were conducted to address these issues. In a series of 12 field experiments, neonicotinoid seed treatments resulted in twospotted spider mite densities greater than those in the untreated check, aldicarb, and acephate treatments. Untreated check and aldicarb treatments had the lowest mite densities. Only aldicarb controlled mites compared to the untreated check. A twospotted spider mite host survey determined that henbit, Lamium amplexicaule L., was the most consistent and preferred host. Carolina geranium, Geranium carolinianum L., cutleaf geranium, Geranium dissectum L., vetch, Vicia spp., volunteer soybean, Glycine max L., purple deadnettle, Lamium purpureum L., and spiny sowthistle, Sonchus asper (L.) Hill, were other frequently infested dicotyledonous species. Herbicide burndown timing in reduced tillage cotton production was not critical, given all weeds were killed before cotton was planted. The herbicide glufosinate was efficacious against T. urticae, providing control equal to low- to mid-rates of labeled acaricides. Including glufosinate in a herbicide burndown program was only beneficial for mite control if living weeds were present at planting. Artificial infestation experiments were adversely affected by unseasonably wet and cool weather. Infestations established at the third true leaf resulted in an average yield loss of 44.7%. It is difficult to make any conclusions about infestations made from first bloom and later because of the difficulty in establishing mite populations later in the season.

Indoor air quality is described as the chemical, physical and biological characteristics of air in a residential or occupational indoor environment. In residential settings, there are many contributions to indoor pollution levels namely; human activities, biological sources and outdoor air. There has been increased focus on house dust due to its potential to contain biological and chemical pollutants in indoor environments. These have the potential to cause harm to human health. The purpose of this study was to conduct toxicological analysis of house dust collected from inside selected Durban residential buildings. The objectives of this study were to isolate, identify and quantify mould occurrence in house dust samples; to measure the occurrence of heavy metals (arsenic, lead and mercury) in house dust; and to analyse the cytotoxicity of house dust on human lung bronchus carcinoma epithelial line (A549) and human lung bronchus virus transformed epithelial cell line (BBM). One hundred and five house dust samples were obtained from households that participated in the South Durban Health Study. In each home, a sample of settled dust was collected, using standardized protocols, then sieved and individually packed into polystyrene bags. The samples were taken from three surface areas namely; living room couches, bed mattresses, and carpets. Well documented methods were used for the isolation, identification and quantification of mould. The samples for heavy metals analysis were sent to Umgeni Water (chemistry laboratory, Pietermaritzburg) where standardised methods were used. Human cell lines were treated with five different dilutions of each house dust extract. Cell viability was assessed using the MTT assay. Toxic effects of house dust extract were analyzed, following house dust extract treatment and cells were stained with double dye (annexin-V- and propidium iodide) and analysed with flow cytometry, and fluorescent microscope. Cytokines were analysed by Microbionix (Neuried, German) using a Luminex®100 plate reader for multiplex human cytokines analysis. There were (n=128) mould types isolated and (n=105) were identified, of which (n=10) were predominately isolated moulds. This was further confirmed by Allerton Provincial Laboratory in Pietermaritzburg. Among the isolated genera in all three surface areas, Rhizopus spp and Penicillium spp were widely distributed throughout surface areas in greater proportion. The overall highest mean which was reported in this study and expressed in colony forming unit per gram (CFU/g) for Penicillium spp ranged (3400 - 62316 CFU/g) obtained from living room couches, followed by Rhizopus spp (5200 - 15990 CFU/g). The mould results were compared with the South African Occupational Health and Safety Act (OHSA) 85 of 1993 as amended suggested guidelines of 1,000, 000 CFU/g. The findings of this study suggest the moulds in the homes studied were below the suggested guideline. However, this does not imply that the indoor conditions are unsafe or hazardous. Instead, the findings act as an indicator of moulds presence indoors. The type of airborne mould, its concentration and extent of exposure and the health status of the occupants of a building will determine the health effects on an individual. Heavy metals were detected in the dust in the following ascending order: arsenic (As) ranged from 1.3 ug/g -18.4 ug/g (mean, 4.26 ug/g), lead (Pb) ranged from 28.0 - 872 ug/g (mean 171.66 ug/g), and mercury (Hg) ranged from 0.6 -19.0 ug/g (mean, 2.22 ug/g). The mean concentration of lead in the dust was within the range of Canadian National Classification guidelines on residential contamination (500 ug/g). There was numerous numbers of samples in this study that exceeded these guidelines. The mean concentration of arsenic was within residential soil guidelines (20 ug/g). Mercury was within limits when compared with Global Hg project guidelines of soil/residential (6.6 ug/g), thought some of samples were notably above this mean. The ability of house dust extract to lower the cell viability which was slightly above 80% (prior treatment) to less than 50% (post treatment) in both cells was observed in this study. The findings in this study showed that dust extract are toxic to human cell lines, and cells undergone a degree of apoptosis and necrosis 62% (A549) and 99% (BBM). The cytokines serve an important role in the non-specific defence external against insults. It was observed that A549 cells up-regulated the release of IL-6 and IL-8 pro-inflammatory cytokines and under-regulated the release of other cytokines analysed (IL-4, IL-13, and TNF-a). BBM cells released IL-4, IL-8 and IL-13 within limit of detection. The presence of moulds in these sampled indoor household dusts, which is comparable with findings elsewhere indoors, show that moulds act as an indicator for building conditions such as dampness, which supports mould growth. Individuals, whether they are sensitized or not, may develop allergic reactions towards spores, thus the elevated numbers of spores quantified in this study are of concern. Some of the heavy metals reported in this study were higher or marginally higher than international norms and guidelines. The findings in this study strongly suggest that house dust extract is toxic to human lung cell lines. It must be noted, however, that this study may not reflect all that happens when a human lung is exposed to house dust. The findings of this study could contribute to the development of South African indoor air guidelines. In conclusion further study needed to be undertaken with respect to air pollution disease such as allergic; the reason being this study shown the reduced expression of cytokines that are involved in allergic inflammation. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2009.