Os inibidores inibidores de serino proteinases do tipo Bowman-Birk (BBI) possuem dois sítios ativos e são encontrados em plantas das famílias Fabaceae e Poaceae. Neste trabalho foi apresentada a estrutura primária e o padrão de expressão de 14 seqüências expressas (EST, expressed sequence tags) de BBI putativos encontradas no banco de dados do "Projeto Transcriptoma da Cana-de-açúcar" (SUCEST). Estas quatorze seqüências foram utilizadas em conjunto com outras 87 seqüências de BBI previamente descritas e depositadas no banco de dados "GenBank" para a construção de árvores filogenéticas da família BBI. A análise filogenética mostrou que os BBI de monocotiledôneas e dicotiledôneas podem ser claramente separados em diferentes grupos e a topologia das árvores filogenéticas sugere um padrão evolutivo diferente das famílias de BBI em plantas. Os inibidores de dicotiledôneas são bem conservados e acumularam diferenças sutis durante a evolução. Em contrapartida, os inibidores de monocotiledôneas são altamente variáveis, indicando a ocorrência de um processo evolutivo interessante, baseado em eventos de duplicação intragênica e mutação. Dois inibidores de serino proteinases, um de tripsina e outro de quimotripsina, derivados do gene que codifica o inibidor Bowman-Birk de soja, foram expressos na superfície do fago filamentoso M13 e utilizados para a construção de bibliotecas de variantes. Para tal foram feitas mutações em quatro aminoácidos do sítio ativo destes inibidores e duas bibliotecas de expressão na superfície de fagos filamentosos foram construídas. Posteriormente, estas bibliotecas foram utilizadas para a seleção de variantes que melhor interagiam com a tripsina bovina e de Diatraea saccharalis e com as enzimas digestivas presentes no extrato intestinal desta praga. Os variantes selecionados foram seqüenciados, analisados e caracterizados. Os resultados mostraram que a técnica de expressão na superfície de fagos filamentosos foi eficiente para selecionar novos inibidores. Além disto, com as mutações realizadas, foi possível transformar a alça de inibição de quimotripsina em uma alça de inibição de tripsina. / The Bowman-Birk inhibitors (BBIs) are double headed inhibitors of serine proteinase found in plants from Fabaceae and Poaceae families. We describe the primary structure and the gene expression profile of 14 putative BBIs from the sugarcane expressed sequence tag (SUCEST) database and show how we used these newly discovered sequences together with 87 previously described BBI sequences from the "GenBank" database to construct phylogenetic trees for the BBI family. Phylogenetic analysis revealed that BBI-type inhibitors from monocotyledonous and dicotyledonous plants could be clearly separated into different groups, while the overall topology of the BBI tree suggests a different pattern of evolution for BBI families in flowering plants. We also found that BBI proteinase inhibitors from dicotyledonous plants were well conserved, accumulating only slight differences during their evolution. In addition, we found that BBIs from monocotyledonous plants were highly variable, indicating an interesting process of evolution based on internal gene duplications and mutation events. Two serine-type proteinase inhibitors, a trypsin and a chymotrypsin, both derived from the soybean Bowman-Birk inhibitor, were expressed on the surface of a filamentous phage. Site mutations were made in four positions of the reactive sites of these inhibitors and two phage-display libraries were constructed. Later, these libraries were used to select better ligands to the bovine and Diatraea saccharalis trypsin and to the midgut enzymes of this insect pest. The selected variants were sequenced, analyzed and characterized. The results showed that the phage-display technique is efficient to select new proteinase inhibitors. Furthermore, it was possible to modify the chymotrypsin loop into a trypsin loop using the library constructed by the insertion of a degenerated primer.

Introdução: Os percevejos de cama são insetos hematófagos pertencentes à família Cimicidae e à ordem Hemiptera. Algumas das espécies desse grupo despertam interesse em Saúde Pública por apresentarem comportamento antropofílico. Atualmente verifica-se uma reemergência das infestações de percevejos de cama em diversas localidades do mundo, principalmente em grandes cidades, já que estas constituem ambientes propícios para sua instalação e proliferação, pois recebem ou abrigam grande número de indivíduos que atuam como fontes de alimentação. Objetivos: Descrever a atual situação das infestações por insetos da família Cimicidae na região Metropolitana de São Paulo, no período de 2004 a 2009. Métodos: estudo descritivo baseado em registros de ocorrência de cimicídeos fornecidos por empresas privadas de controle de pragas e por órgãos públicos de vigilância, pesquisa e controle sediados na Região Metropolitana de São Paulo. Identificação de espécies de cimicídeos recebidas no Laboratório de Entomologia em Saúde Pública da Faculdade de Saúde Pública, em decorrência de coletas realizadas na região estudada. Resultados: Foram recebidos 369 registros de ocorrência de cimicídeos, sendo 325 provenientes do município de São Paulo e o restante dos municípios vizinhos à capital. As residências somaram 181 registros ou 68,04 por cento dos casos, enquanto as infestações ocorridas em estabelecimentos comerciais e/ou de serviço foram responsáveis por 85 registros (31,95 por cento). Cimex lectularius foi a espécie predominante, sendo responsável por 262 registros (92,25 por cento), enquanto Cimex hemipterus foi apontado em apenas um registro (0,35 por cento). Os registros do município de São Paulo mostraram uma correlação positiva significativa entre padrões socioeconômicos mais elevados e alto número de ocorrências registradas. Um total de 354 espécimes coletados na região metropolitana de São Paulo foi recebido pelo laboratório entre abril de 2008 e dezembro de 2009. Todas as amostras recebidas foram identificadas como sendo de C. lectularius. Conclusões: Ficou evidenciado que ocorrem infestações regulares por cimicídeos na Região Metropolitana de São Paulo. Os registros de ocorrência de infestações estão, no entanto, concentrados às regiões socioeconomicamente mais favorecidas do município de São Paulo. A subnotificação das infestações é uma realidade, o que minimiza a gravidade do quadro apresentado / Introduction: The bed bugs are hematophagous insects belonging to the family Cimicidae and to the order Hemiptera. Some of the species of this group draw attention in Public Health because they have anthropophilic behavior. We observe the resurgence of bed bug infestations in many different places all over the world, especially in big cities, once they are very propense environment for its installation and proliferation due to the fact that there are many individuals living there. Aims: The aim of this research is to describe the real situation of infestations by Cimicidae insects in the metropolitan region of São Paulo from 2004 to 2009. Methodology: this is a descriptive study based on the registries of occurrences provided by private companies specialized in pest control and public departments of control and research in the metropolitan region of São Paulo. Identification of the Cimicidae insects received, resulting from collections in the region. Results: Were received 369 registries of bed bug occurrences in the period, 325 of those belonging to the city of São Paulo. Registries of infestations in houses were 181, corresponding to 68,04per cent of the cases. Registries of infestations in business organizations were 85, corresponding to 31,95per cent. Cimex lectularius was the predominant species with 262 registries, corresponding to 92,25per cent. Cimex hemipterus was mencioned only once (0,35per cent). Registries in São Paulo show a very positive correlation between high social and economical standards and a high number of registries of occurrences. LESP received 354 samples collected in RMSP from April 2008 to December 2009, all of them identified as C. lectularius. Conclusion: It was evident that there are very regular bed bug infestations in the metropolitan region of São Paulo. Registries are concentrated in the high social and economical standards regions of the city of São Paulo. Social and behavior patterns influence the notifications. Lack of notification happens and that minimizes the problemThe bed bugs are hematophagous insects belonging to the family Cimicidae and to the order Hemiptera. Some of the species of this group draw attention in Public Health because they have anthropophilic behavior. We observe the resurgence of bed bug infestations in many different places all over the world, especially in big cities, once they are very propense environment for its installation and proliferation due to the fact that there are many individuals living there. Aims: The aim of this research is to describe the real situation of infestations by Cimicidae insects in the metropolitan region of São Paulo from 2004 to 2009. Methodology: this is a descriptive study based on the registries of occurrences provided by private companies specialized in pest control and public departments of control and research in the metropolitan region of São Paulo. Identification of the Cimicidae insects received, resulting from collections in the region. Results: Were received 369 registries of bed bug occurrences in the period, 325 of those belonging to the city of São Paulo. Registries of infestations in houses were 181, corresponding to 68,04% of the cases. Registries of infestations in business organizations were 85, corresponding to 31,95%. Cimex lectularius was the predominant species with 262 registries, corresponding to 92,25%. Cimex hemipterus was mencioned only once (0,35%). Registries in São Paulo show a very positive correlation between high social and economical standards and a high number of registries of occurrences. LESP received 354 samples collected in RMSP from April 2008 to December 2009, all of them identified as C. lectularius. Conclusion: It was evident that there are very regular bed bug infestations in the metropolitan region of São Paulo. Registries are concentrated in the high social and economical standards regions of the city of São Paulo. Social and behavior patterns influence the notifications. Lack of notification happens and that minimizes the problem.

Dans les agroécosystèmes, l'utilisation de la biodiversité pour la régulation naturelle des arthropodes nuisibles vise à proposer une protection agroécologique des cultures, en alternative à la protection agrochimique actuelle. Notre étude a porté sur les agroécosystèmes à base de manguiers à La Réunion, avec l'objectif de comprendre les facteurs qui influencent la biodiversité et la régulation des arthropodes nuisibles. Cet agroécosystème est caractérisé par une importante diversité (797 espèces d'arthropodes et 114 espèces de plantes) et nos résultats ont révélé l'existence de contrôles ascendants et descendants positifs de cette biodiversité au sein des communautés. Nous avons également mis en évidence les services et disservices des espèces dominantes de fourmis envahissantes : deux d'entre elles fournissent un service de prédation et l'une d'elles réduit la diversité des ennemis naturels omnivores, ce qui semble expliquer la relation négative entre la diversité des omnivores et le service de prédation. Enfin, nous avons montré l'effet positif de la diversité des parasitoïdes et de la diversité des prédateurs, respectivement sur l'abondance des populations de la Cochenille des Seychelles et sur le service de prédation. Le seul effet significatif du paysage qui a été décelé est l'effet positif de la proportion des vergers de manguiers sur l'abondance du Thrips Sud-Africain des agrumes. L'ensemble de ces résultats nous permet d'identifier deux leviers pour la protection agroécologique des vergers de manguiers : l'implantation d'enherbements diversifiés dans les vergers ; la gestion collective du paysage en y limitant la proportion des vergers de manguiers. / In agroecosystems, the use of biodiversity for natural control of arthropod pests aims to propose an agroecological crop protection, as an alternative to current agrochemical protection. Our study focused on mango agroecosystems in Reunion Island, with the goal of understanding the factors that influence biodiversity and control of arthropod pests. This agroecosystem is characterized by a large diversity (797 arthropod species and 114 plant species) and our results highlight the positive bottom-up and top-down controls of biodiversity in communities. We also highlight the services provided by the dominant species of invasive ants in pest regulation. Two species provide a predation service, and one reduces the diversity of natural enemies of omnivores and appears to explain the negative relationship between omnivore diversity and predation. Finally, we highlight the positive effect of parasitoid diversity and predator diversity on, respectively, the abundance of Seychelles mealybugs and on predation in general. The only significant landscape effect measured in our work is the positive effect of the proportion of mango orchards on the abundance of South African citrus Thrips. These results allow us to identify two factors in the agroecological protection of mango orchards in Reunion: the management of diversified ground cover in orchards; and collective landscape management by limiting the proportion of mango orchards.

Submitted by (edna.saturno@ufrpe.br) on 2016-12-19T15:11:21Z No. of bitstreams: 1 Maria Virginia Alves Xavier.pdf: 938724 bytes, checksum: 3969de87ac989fbf6102e3ade913c13d (MD5) / Made available in DSpace on 2016-12-19T15:11:21Z (GMT). No. of bitstreams: 1 Maria Virginia Alves Xavier.pdf: 938724 bytes, checksum: 3969de87ac989fbf6102e3ade913c13d (MD5) Previous issue date: 2014-02-24 / Biodiesel production has received enough encouragement and among the crops with potential applicability to this highlights the physic nut (Jatropha curcas L. ) , which has been identified as one of the most promising crops for biodiesel and inclusion in family production chain , which has opened up broad prospects for growth in the areas of planting this crop in semi-arid northeast . Several factors limit the productivity of Jatropha, with emphasis on the attack by pests such as spider mite Tetranychus bastosi Tuttle , Baker & Sales (Acari : Tetranychidae) . Among the methods currently used for alternative pest control is gaining prominence employment of plant extracts due to the presence of secondary metabolites present in some plants and their low toxicity to the environment and to humans . In the present work we evaluated the potential of plant extracts Myracrodruon urundeuva All Br ( Anacardiaceae ) , Croton blanchetianus Baill (Euphorbiaceae) and Ziziphus joazeiro Mart . (Rhamnaceae ) on the mite T. bastosi associated with the culture of Jatropha. We evaluated the effect of the extract of M. urundeuva at different doses (0 , 5 % , 10 % , 15 % , 20 % and 25 % ) on the biology and fertility life table T. bastosi . It was observed that the extract of M. urundeuva prolonged cycle of development of the mite and with increasing dosages, prolonged the longevity of T. bastosi . With respect to the life and fertility table, it was found that there was no effect of the extract for the parameters, except for the survival and viability of eggs, where there was a lower progeny survival at a dose of 10% and a lower egg viability in strengths of 15 % and 20 %. Toxicity and repellency of the extracts of M. urundeuva , C. blanchetianus and Z. joazeiro was also evaluated . Generally extracts showed toxic effect on adults of T. bastosi the concentrations tested. The extract of Z. joazeiro showed the highest mortality rates (90 %) mean mortality of individuals. With regard to the repellency of these extracts, all treatments were shown repellents for females of Tetranychus bastosi classified as repellent treatment, except for the 5% dose of extract of M. unrundeuva . / A produção de biodiesel vem recebendo bastante incentivo e dentre as culturas agrícolas com potencial para esta aplicabilidade destaca-se o pinhão-manso (Jatropha curcas L.), que vem sendo apontada como uma das mais promissoras para o biodiesel e inserção na cadeia produtiva familiar. Isso tem aberto amplas perspectivas para o crescimento das áreas de plantio desta cultura no semiárido nordestino. Diversos fatores limitam a produtividade do pinhão-manso, havendo destaque para o ataque por pragas, como o ácaro Tetranychus bastosi Tuttle, Baker & Sales (Acari: Tetranychidae), o qual foi registrado recentemente em Pernambuco. Dentre os métodos utilizados atualmente para o controle alternativo de pragas vem ganhando destaque o emprego de extratos vegetais, devido à presença metábólitos secundários presentes em algumas plantas e à sua baixa toxicidade para o meio ambiente e para o homem. No presente trabalho avaliou-se o potencial de extratos vegetais de Myracrodruon urundeuva Fr. All (Anacardiaceae), Croton blanchetianus Baill (Euphorbiaceae) e Ziziphus joazeiro Mart. (Rhamnaceae,) sobre o ácaro T. bastosi associado à cultura do pinhão- manso. Avaliou-se o efeito do extrato de M. urundeuva, em diferentes dosagens (0, 5%, 10%, 15%, 20% e 25%) sobre a biologia e a tabela de vida de fertilidade de T. bastosi. Observou-se que o extrato de M. urundeuva prolongou o ciclo de desenvolvimento deste ácaro e com o aumento das dosagens, houve um prolongamento da longevidade de T. bastosi. No que se refere à tabela de vida e fertilidade, verificou-se que não houve efeito do extrato para os parâmetros analisados, exceto para a sobrevivência e viabilidade de ovos, onde observou-se uma menor sobrevivência da progênie na dose de 10% e uma menor viabilidade de ovos nas dosagens de 15% e 20%. Também foi avaliada a toxicidade e repelência dos extratos de M. urundeuva, C. blanchetianus e Z. joazeiro sobre T. bastosi. De uma forma geral os extratos demonstraram efeito tóxico para adultos de T. bastosi nas concentrações testadas. O extrato de Z. joazeiro apresentou as maiores taxas de mortalidade (90% de mortalidade média dos indivíduos). No que se refere à repelência destes extratos, todos os tratamentos se mostraram repelentes para fêmeas de Tetranychus bastosi, classificados como tratamentos repelentes, exceto para a dosagem de 5% do extrato de M. unrundeuva.

Este estudio constituye una importante fuente de información sobre el potencial de los sírfidos depredadores (Diptera: Syrphidae, Syrphinae) como agentes biológicos para el control de plagas en cultivos agrícolas en Venezuela. Las larvas de los Syrphidae presentan una morfología muy variada y poseen una gran diversidad de modos de vida. La mayor parte de los representantes de la subfamilia Syrphinae, son depredadores de una amplia gama de hemípteros de cuerpo blando aunque también pueden alimentarse de otros artrópodos. Las principales presas de los sírfidos depredadores son los áfidos o pulgones (Aphididae), escamas (Coccoidea), aleuródidos (Aleyrodidae) y trips (Thripidae). Para la realización de la presente Tesis doctoral se realizó un muestreo en los principales cultivos del estado Lara y se revisó la colección del Museo de Entomología José M. Osorio (MJMO = UCOB, según el Biodiversity Collections Index) de la Universidad Centroccidental "Lisandro Alvarado". También se revisaron ejemplares de la colección del Museo del Instituto de Zoología Agrícola (MIZA) de la Universidad Central de Venezuela. Entre los resultados de la tesis, se presenta una base de datos con los sírfidos depredadores estudiados con un total de 2571 ejemplares agrupados en 11 géneros y 59 especies. Del total de especies estudiadas, al menos se identificaron 15 nuevos taxa para la ciencia. Adicionalmente, se realizó un inventario de las presas y plantas asociadas a cada especie de Syrphidae depredador. Se reportaron nuevas especies de presas y plantas asociadas que aumentan de manera significativa el conocimiento de estas relaciones conocidas hasta la fecha en Venezuela. Como ejemplo, para A. exotica, se indican 6 nuevas presas y 23 plantas hospedantes; para P. clavatus se registran 7 nuevas plantas hospedantes. Por último, destacar 26 nuevos registros de presas relacionadas con el género Ocyptamus sobre 33 especies de plantas asociadas, presentando la mayor diversidad de presas de todos los sírfidos estudiados. En función de los resultados obtenidos en el muestreo se procedió al estudio del potencial biológico de Allograpta exotica, Pseudodoros clavatus y Ocyptamus dimidiatus, utilizando como presa al áfido de las leguminosas, Aphis craccivora en condiciones de laboratorio. Los parámetros biológicos de la especie (A. exotica) fueron estudiados en detalle. Las curvas de respuesta funcional de A. exotica se ajustaron mejor y mostraron el valor más alto de R2 para el modelo Polinomial indicando una fuerte correlación entre el aumento de áfidos depredados por A. exotica y las diferentes densidades ofrecidas de A. craccivora. El coeficiente de determinación para el modelo de Holling sugiere que A. exotica responde al Tipo de curva II. De manera complementaria a los estudios anteriores, se procedió al análisis de la morfología preimaginal de los géneros Allograpta, Pseudodoros y Ocyptamus. Además, se estudió la morfología preimaginal de Eosalpingogaster umbra Mengual y Thompson, Salpingogaster nigra Schiner, Leucopodella sp. nov. y xanthandrus bucephalus (wiedemann) aportando las primeras informaciones conocidas sobre su morfología preimaginal y las implicaciones sistemáticas derivadas. Se describen por vez primera el pupario, la larva madura (L-3) y la quetotaxia de O. dimidiatus y O. gastrostactus. También se describen los puparios de Ocyptamus funebris, O. norina, O. phaeopterus O. stenogaster, Ocyptamus lividus, O. tristani y Ocyptamus sp.nov aff. attenuatus. Por último se incluye una clave de identificación diagnóstica de las especies de Ocyptamus cuya morfología preimaginal ha sido analizada en esta memoria. / Consejo de Desarrollo Científico, Humanístico y Tecnológico de la Universidad Centroccidental Lisandro Alvarado (CDCHT-UCLA), financiamiento al proyecto de Tesis Doctoral 003-DAG-2007.

We studied the characteristics and effects of the Argentine ant invasion on the native ants and other arthropods. Moreover, we assessed the effects of L. humile winter nest aggregations extirpation on its population dynamics. We measured the spread of its invasion and evaluated its nest-site preferences. Artificial nests used as a control tool were also assessed. Results indicate that the invasion causes important changes in the native ant community structure. The invasion spread is influenced by air temperature, and habitat perturbations could be favouring a faster expansion. The extirpation diminished the abundance of this ant and disturbed its population dynamics. In order to make this method more efficient, extirpation should be made in the edge of the invasion, and should focus on nests under larger rocks where mature nests are more likely to be found. Finally, this method is proposed mainly for controlling its invasion in closed or isolated areas. / Es van comparar les característiques i els efectes de la invasió de la formiga argentina sobre la comunitat de formigues natives, i altres artròpodes. Es va avaluar l'efecte de l'extirpació d’agregacions de nius d’hivern, la selecció de llocs de nidificació i l'ús de nius artificials com a eina de control, i es va mesurar la seva taxa d'expansió. Es va trobar que la invasió provoca canvis importants en la comunitat de formigues natives. La temperatura ambiental influeix en l'expansió, i les pertorbacions de l'hàbitat podrien afavorir una propagació més ràpida. L'extirpació disminueix la seva abundància i pertorba la seva dinàmica poblacional. L'extirpació s'ha de fer al marge de la invasió, i s'ha de centrar en nius situats sota les pedres més grans que és on hi ha més probabilitat de trobar nius madurs. Finalment, aquest mètode es proposa principalment per al control de la invasió en àrees tancades o aïllades.

The soil-borne fungi Rhizoctonia solani Kuhn and Sclerotinia sclerotiorum De Bary are ubiquitous plant pathogens with a wide host range. They are among the most widespread and destructive diseases of many crops, including sunflowers. Although in many cases, the use of chemicals appears to be the most economical and efficient means of controlling plant pathogens, their environmental concerns and the development of tolerance in pathogen populations have led to drastic reduction in their usage and increased the need to find alternative means of disease control. The potential benefits of applying Trichoderma harzianum Rifai and silicon (Si) nutrition to plants have been extensively reviewed. In this study, the ability of T. harzianum (Eco-T®), soluble silicon, and their combination was evaluated on sunflower (Helianthus annuus L.), for their potential to suppress pathogenic strains of R. solani and S. sclerotiorum. The ability of this crop to take up and accumulate Si in different plant parts was also investigated. In vitro assessment of fungal responses to Si in PDA showed that both R. solani and S. sclerotiorum were inhibited in the presence of Si. More inhibition was observed as the Si concentration increased with a relative increase in pH. Maximum growth inhibition was observed at 3000 mg ;-1 – 6000 mg ;-1 of PDA. No difference in inhibition between the two pathogens was observed, thus confirming the fungitoxic/suppressive ability of high Si concentrations to fungal growth. In addition, in vivo trials showed that the Si concentration of 200 mg ;-1 applied weekly significantly increased the dry weight of plants inoculated with R. solani and S. sclerotiorum and was therefore considered the optimum concentration. Assessments on in vitro antifungal activities of Eco-T® on R. solani and S. sclerotiorum, showed that Eco-T® significantly inhibited mycelial growth, in both dual culture methods and volatile and non-volatile compounds produced by Eco-T®. In addition, the combination of Eco-T® and Si was most effective in suppressing damping-off and increasing plant dry weight of sunflower seedlings in the greenhouse. The combination of Si and Eco-T® significantly increased percentage germination, number of leaves and head dry weight of the sunflower cultivars tested. Silicon alone increased growth but was unable to control R. solani and S. sclerotiorum effectively. Rhizotron studies showed that S. sclerotiorum infected the host through the roots and the stem, whereas R. solani only infected the host through the roots. A study on Si uptake and distribution showed that sunflower accumulates Si in various plant tissues. Analysis of plant tissues revealed that more Si was accumulated in leaves > stems > roots, with the Si levels in leaves being significantly higher than in stems and roots. In conclusion, Si alone could be used to increase growth but was unable to control R. solani and S. sclerotiorum. However, Si together with Eco-T® provides an environmentally friendly alternative for the control of R. solani and S. sclerotiorum, and enhanced plant growth and yield. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Gastrointestinal nematode parasites cause great losses in the production of small ruminants through reduced productivity and the cost of preventive and curative treatments. Because of the threat of anthelmintic resistance, biological control of sheep nematodes has been identified as an alternative to anthelmintic drugs. Bacillus thuringiensis (Bt) (Berliner) and Clonostachys rosea (Schroers) have been widely studied as biocontrol agents. B. thuringiensis has been used for the biocontrol of insects and C. rosea has been successfully used as biocontrol agent of Botrytis cinera (De Bary) in plants. B. thuringiensis and C. rosea strains were isolated from soil collected from the Livestock Section at Ukulinga Research Farm, University of KwaZulu Natal, Pietermaritzburg. Twenty-five strains of Bt and 10 strains of C. rosea were successfully isolated. The Bt colonies were identified by their circular, white, flat and undulate character, and the gram-positive and rod-shaped endospores. C. rosea was identified by white colonies on Potato-dextose agar and the characteristic conidiophores, which were branched and showed phialides at the tips. In vitro screening of the isolates was undertaken to select the best isolates. The isolates that caused significantly greater mortality were Bt isolate B2, B10 and B12 and C. rosea isolates P1, P3 and P8. These isolates caused substantial nematode mortality in both faeces and water bioassay. Nematode counts were reduced by 28.5% to 62% and 44% to 69.9% in faecal bioassay for Bt and C. rosea, respectively. In the water bioassay, nematode counts were reduced by 62% to 85% for Bt and by 62.7% to 89.3% for C. rosea. The best inoculum level at which the best isolates were most effective, and the optimum frequency of application were determined. The trial was conducted using bioassays with faeces and water. Inoculum levels of 10(6), 10(8), 10(10), 10(12) spores ml-1 for Bt and 10(6), 10(8) and 10(10) conidia ml-1 for C. rosea was used in the faecal bioassay. The inoculum levels tested in water bioassay were 10(6), 10(8), 10(10) and 10(12) spores ml-1 for Bt and 10(9), 10(10), 10(11), 10(12) conidia ml-1 for C. rosea. In the faecal bioassay, B2 was the most effective Bt isolate at an inoculum level of 10(10) spores ml-1. Isolate P3 was the best C. rosea isolate at 10(8) conidia ml-1. In the water bioassay, Isolate P3 caused a mortality of 85% at inoculum levels of 10(9), 10(10) and 10(11) conidia ml-1. The performance of biological control agents in the field is sometimes inconsistent. Combining different biocontrol agents may be a method of improving their reliability and performance. However, the combination of most of the isolates was antagonistic, with efficacy less than that of either individual biocontrol agent. In particular, Isolate P3 was more effective when used alone than when combined with any other isolates. Therefore, the combination of biocontrol agents does not always result in synergistic interaction. There were some additive interactions between two bacterial isolates, and with one bacterial and fungal combination. The effect of feeding the best of the biocontrol agents, or diatomaceous earth (DE), was evaluated in sheep. Two doses of Bt (1g and 2g kg-1BW) and C. rosea (1g kg-1BW) reduced the numbers of L3 nematode larvae in sheep faeces. The DE product (at 15% of feed) also reduced L3 numbers but it was less effective than either the Bt or the C. rosea products. Nematode counts were reduced by 74.6%, 75.1%, 84.6%, 68.5% and 27.5% for Bt 1g kg-1BW, Bt 2g kg-1BW, C. rosea (1g kg-1 BW), DE and control, respectively. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

The role of interspecific competition as a regulating force in natural populations has been controversial, especially for phytophagous insect communities. A series of manipulative experiments using enclosure cages were conducted to evaluate the role of interspecific competition between a weevil and a fly, two seed feeding agents released against spotted knapweed in North America. The fly, an inferior biological control agent, was the superior competitor. Consequences of the antagonistic interaction included reduced seed destruction compared to if just the weevil was released on its own. The role of plant phenology on insect herbivore density was also assessed. The implications of phenologyinduced variation in insect density were evaluated with respect to competition between the fly and the weevil and were found to be important. Hypotheses of four plantmediated mechanisms of interspecific competition were also tested. Results support resource preemption as a competitive mechanism. / vii, 97 leaves ; 29 cm

The entomopathogenic fungus Beauveria bassiana and the bacterium Bacillus thuringiensis var. israelensis (Bti) have been widely studied for their role in biocontrol against many arthropods and extensively exploited for insect pest control. The purpose of this study was to evaluate the effect of four B. bassiana and two Bti formulations and their respective combinations, for the biological control of the common house fly, Musca domestica L., a major pest in poultry facilities. In vitro screening was undertaken to select the best B. bassiana isolates from 34 B. bassiana isolates and two Paecilomyces isolates. All the isolates of B. bassiana were found to be effective against adult house flies, but were marginally effective in controlling fly larvae. The Paecilomyces isolates were non-pathogenic towards both adult house flies and larvae. The best four isolates R444, 7320, 7569 and 7771 caused >90% mortality within 2d and were subjected to dose-mortality bioassays. Microscopic studies using light and scanning electron microscopy indicated the different durations of the lifecycle of B. bassiana development on the house fly. High temperature was found to delay conidial germination. Spore germination and mycelial growth were also inhibited by high adjuvant concentrations. Laboratory baseline bioassay data established, a dose-time response relationship using a waterdispersible granules (WDG) Bti formulation that demonstrated that the susceptibility of M. domestica larvae to a given concentration of Bti increased as the duration of exposure increased. In the laboratory studies, the LC50 and LC90 values of Bti for the larvae ranged between 65 - 77.4 and 185.1 - 225.9?g ml-1, respectively. LT50 and LT90 values were 5.5 and 10.3d respectively. In the field, a concentration of 10g Bti kg-1 (bran formulation) of feed resulted in 90% reduction of larvae for 4wk post-treatment. A higher concentration (2g L-1) of Bti in spray (WDG) applications was not significantly more effective than the lower concentration of 1g L-1. Thus, adding Bti to chicken feed has potential for the management and control of house flies in cagedpoultry facilities. The impact of oral feed applications of a bran formulation of Bti and a commercial chemical larvicide, Larvadex®, were compared with respect to their efficacy on the control of house fly 3 larval populations in poultry manure. The sublethal effects were manifested in terms of decreasing emergence of adult house flies. Although Larvadex® reduced larval density and caused significant reductions in emergence of adult house flies, it generally exhibited weaker lethal effects than Bti. The reduction levels achieved as a result of feeding 250mg Bti kg-1 at 5wk were similar to those achieved as a result of feeding twice the amount of Larvadex® at 4wk to the layers. From both an efficiency and economic perspective, comparisons to assess the impact of combining different concentrations of the two Bti formulations were carried out to evaluate their success in controlling house fly larvae and adults in poultry houses. The percentage mortality of larvae accomplished as a result of using a combination of 250mg kg-1 Bti in feed and 2g L-1 spray applications was equivalent to that obtained as a result of combining 500mg kg-1 Bti in feed and 1g L-1 spray application. The cost-benefit analysis (expressed in terms of mortality of larvae) indicated that the most effective combination for control of house fly larvae and fly emergence was the 500mg kg-1 in feed and 2g L-1 spray application combination that resulted in 67% larval mortality and 74% inhibition of adult house fly emergence. This study presents commercial users with possible combinations of applications of the two Bti formulations. Comparisons of larval mortalities and house fly emergence resulting from the Bti - B. bassiana treatments with those from Larvadex® - B. bassiana treatments, showed better control levels compared to any of the individual agents alone. The Bti treatments were more effective at controlling larval populations and inhibiting the emergence of house flies than Larvadex®, even when Larvadex® was applied together with B. bassiana. The effects of the Bti - B. bassiana and the Larvadex® - B. bassiana interactions were additive. These trials suggest that the efficacy of Bti in the control of house fly larvae may be improved with frequent applications of B. bassiana. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.