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Bruchid pests are of considerable economic importance, infesting legume seeds and pods in fields and stores, predominately in the semi-arid tropics. One of the foremost bruchid pests"Callosobruchus maculatus is a niche generalist in that it can infest seeds whilst within pods or when loose. It exhibits a much greater degree of polyphagy than its wild relatives, perhaps partly due to behavioural plasticity. As their larvae are restricted to a single seed, resources available for growth are directly related to egg distribution by the ovipositing female. Host selection is a complex process and involves host finding, recognition (which may occur before or after contact with the plant), and host acceptance which is manifested as contact inspection behaviour and culminates in oviposition. Numerous factors influence these processes including the nature of host chemistry and the presence of conspecific epideictic pheromones. The purpose of this study was to investigate the factors which modulate the tendency to oviposit and oviposition behaviour itself. 2 The oviposition behaviour of newly emerged beetles was recorded on several seeds that vary in their attractiveness as hosts. The behavioural repertoire and the stereotypical sequences that characterise the acceptance or rejection of a host were recorded on pristine and egg laden seeds. These sequences were used to construct flow charts of transitions between the most common behaviours. Several indicators of a host's acceptahility were identified and quantified, including the duration of selected key behaviours. The combination of behaviours exhibited, their position in the transitional matrix and their respective durations, indicated the relative acceptability of the host seeds studied, and provided information on how the different sense organs have complementary roles in the process of host acceptance. This demonstrated that the perception of primary host and conspecific stimuli which influence host acceptance is undertaken by the palps and., to a lesser extent, by the antennae. The study of oviposition behaviour in conjunction with studies on the course of oviposition over extended periods on real and artificial hosts provided the tools by which the chemical bases of host acceptance could be investigated. Host seed extracts were screened for their ability to influence behaviour, and some of the active components were identified as a number of commonly occurring fatty acids. These same fatty acids have been shown to stimulate egg laying, and in different proportions and concentrations, to deter oviposition both as components of a conspecific oviposition deterrent pheromone, and as components of vegetable oils added to stored seeds as a protectant

Dentre 45 isolados de Hyphomycetes testados, oito de Beauveria bassiana e quatro de Metarhizium anisopliae causaram em Tetranychus urticae, mortalidades superiores a 80 e 90%, respectivamente, cinco dias após a inoculação na concentração de 5x10 7 conídios/mL. Hirsutella sp. atingiu 73% de mortalidade na concentração de 1,7x10 7 conídios/mL. Entre 80 a 100% dos cadáveres de ácaros colonizados pelos isolados de B. bassiana e M. anisopliae apresentavam, internamente, cristais de cálcio. Conídio aéreo, blastósporo e célula de levedura de cinco isolados B. bassiana foram patogênicos a esta praga. Diferenças significativas (P ³ 0,05) para CL50 e coeficiente angular entre os isolados e entre as estruturas infectivas foram observadas. Os valores da CL50 variaram de 4,95x10 6 a 8,21x10 7 estruturas infectivas/mL. Não houve diferença significativa entre as estruturas infectivas para os dois parâmetros avaliados, contudo, houve diferenças significativas para a CL50 entre as estruturas infectivas em um mesmo isolado de B. bassiana. Três formulações de fungicidas, 24 de inseticidas e/ou acaricidas foram compatíveis com B. bassiana, sendo formulados com as seguintes moléculas: propamocarb hidrocloreto, enxofre, abamectin, acefato, acetamiprid, betacyflutrin, bifentrina, ciromazina, deltametrina, diafentiuron, diflubenzuron, dimetoato, fenpropatrina, fenpyroximate, fenvalerate, imidacloprid, metamidofós, propargite, tebufenozide e triclorfon. Houve grande variação na toxicidade dos produtos dentro de cada grupo químico e produtos formulados com a mesma molécula química. B. bassiana foi eficiente no controle de T. urticae em crisântemo (Dendranthema grandiflora) cultivado em estufa, quando pulverizado na concentração de 2x10 8 conídios/mL. O controle microbiano foi superior ao proporcionado pelo controle químico utilizado na propriedade agrícola. Efetuando-se quatro pulverizações do fungo em um período de 14 dias, a densidade reduziu de 1,8 para 0,1 ácaro/folha. Na cultura do morango (Fragaria spp.) a eficiência de B. bassiana foi inferior ao crisântemo, com densidade média de ácaros ao longo de 21 dias de avaliação para as concentrações 1x10 8 e 5x10 7 conídios/mL de 13 ácaros/folíolo, contra 43 ácaros/folíolo nas parcelas não tratadas. As variedades de morango Campinas e Princesa Isabel foram as que apresentaram as menores densidades do ácaro, contudo, não houve evidência de que estas variedades interferiram na eficiência de controle da praga por B. bassiana. Assim, M. anisopliae, B. bassiana e Hirsutella sp. foram os fungos mais promissores para serem formulados como micoacaricidas para o controle de T. urticae. / Among 45 isolates of hyphomycetes tested against Tetranychus urticae, 8 Beauveria bassiana and 4 Metarhizium anisopliae isolates caused mortality > 80 and 90%, respectively, 5 days after inoculation with 5x10 7 conidia/mL. Hirsutella sp. caused 73% mortality at a concentration of 1.7x10 7 conidia/mL. Eighty to 100% of cadavers infected by B. bassiana or M. anisopliae isolates had calcium crystals inside their bodies. Conidia, blastospores and yeastlike cells of five B. bassiana isolates were pathogenic against this pest. Significant differences (P ³ 0.05) were observed among the LC50's and slopes of dose-mortality lines for the different isolates and infective structures. LC50 values ranged from 4.95x10 6 to 8.21x10 7 cells/mL. There were no significant differences among the infective structures in the two tested variables. However, there were significant differences among the LC50's with different infective structures within the same B. bassiana isolate. Three fungicide formulations and 24 insecticides and/or mitecides were compatible with B. bassiana including those with the following active ingredients: propamocarb hydrochloride, sulphur, abamectin, acephate,acetamiprid, betacyfluthrin, bifenthrin, cyromazine, deltamethrin, diafentiuron, diflubenzuron, dimethoate, fenpropathrin, fenpyroximate, fenvalerate, imidacloprid, methamidophos, propargite, tebufenozide and trichlorfon. There was large variability in the toxicity of products withing a chemical group and products containing the same active ingredient. B. bassiana was an efficient T. urticae mite control in chrysanthemum (Dendranthema grandiflora), when applied at a concentration of 2x10 8 conidia/mL. Microbial control was better than that provided by chemical pesticides normally used in the greenhouses. With four fungal sprays within 14 days, the mite density was reduced from 1.8 to 0.1 mite/leaf. In strawberry (Fragaria sp.), T. urticae control was lower than in chrysanthemum, with mean density of mites for 21 days after application of 1x10 8 or 5x10 7 conidia/mL at 13 mites/leaflet, compared to 43 mites/leaflet in control plots. The strawberry varieties 'Campinas' and 'Princesa Isabel' had the lowest mite densities, however, these varieties did not affect the efficacy of mite control by B. bassiana. Thus, M. anisopliae, B. bassiana and Hirsutella sp. were the most promissing fungi to be formulated as mycomiticides for T. urticae control.

Dentre 45 isolados de Hyphomycetes testados, oito de Beauveria bassiana e quatro de Metarhizium anisopliae causaram em Tetranychus urticae, mortalidades superiores a 80 e 90%, respectivamente, cinco dias após a inoculação na concentração de 5x10 7 conídios/mL. Hirsutella sp. atingiu 73% de mortalidade na concentração de 1,7x10 7 conídios/mL. Entre 80 a 100% dos cadáveres de ácaros colonizados pelos isolados de B. bassiana e M. anisopliae apresentavam, internamente, cristais de cálcio. Conídio aéreo, blastósporo e célula de levedura de cinco isolados B. bassiana foram patogênicos a esta praga. Diferenças significativas (P ³ 0,05) para CL50 e coeficiente angular entre os isolados e entre as estruturas infectivas foram observadas. Os valores da CL50 variaram de 4,95x10 6 a 8,21x10 7 estruturas infectivas/mL. Não houve diferença significativa entre as estruturas infectivas para os dois parâmetros avaliados, contudo, houve diferenças significativas para a CL50 entre as estruturas infectivas em um mesmo isolado de B. bassiana. Três formulações de fungicidas, 24 de inseticidas e/ou acaricidas foram compatíveis com B. bassiana, sendo formulados com as seguintes moléculas: propamocarb hidrocloreto, enxofre, abamectin, acefato, acetamiprid, betacyflutrin, bifentrina, ciromazina, deltametrina, diafentiuron, diflubenzuron, dimetoato, fenpropatrina, fenpyroximate, fenvalerate, imidacloprid, metamidofós, propargite, tebufenozide e triclorfon. Houve grande variação na toxicidade dos produtos dentro de cada grupo químico e produtos formulados com a mesma molécula química. B. bassiana foi eficiente no controle de T. urticae em crisântemo (Dendranthema grandiflora) cultivado em estufa, quando pulverizado na concentração de 2x10 8 conídios/mL. O controle microbiano foi superior ao proporcionado pelo controle químico utilizado na propriedade agrícola. Efetuando-se quatro pulverizações do fungo em um período de 14 dias, a densidade reduziu de 1,8 para 0,1 ácaro/folha. Na cultura do morango (Fragaria spp.) a eficiência de B. bassiana foi inferior ao crisântemo, com densidade média de ácaros ao longo de 21 dias de avaliação para as concentrações 1x10 8 e 5x10 7 conídios/mL de 13 ácaros/folíolo, contra 43 ácaros/folíolo nas parcelas não tratadas. As variedades de morango Campinas e Princesa Isabel foram as que apresentaram as menores densidades do ácaro, contudo, não houve evidência de que estas variedades interferiram na eficiência de controle da praga por B. bassiana. Assim, M. anisopliae, B. bassiana e Hirsutella sp. foram os fungos mais promissores para serem formulados como micoacaricidas para o controle de T. urticae. / Among 45 isolates of hyphomycetes tested against Tetranychus urticae, 8 Beauveria bassiana and 4 Metarhizium anisopliae isolates caused mortality > 80 and 90%, respectively, 5 days after inoculation with 5x10 7 conidia/mL. Hirsutella sp. caused 73% mortality at a concentration of 1.7x10 7 conidia/mL. Eighty to 100% of cadavers infected by B. bassiana or M. anisopliae isolates had calcium crystals inside their bodies. Conidia, blastospores and yeastlike cells of five B. bassiana isolates were pathogenic against this pest. Significant differences (P ³ 0.05) were observed among the LC50's and slopes of dose-mortality lines for the different isolates and infective structures. LC50 values ranged from 4.95x10 6 to 8.21x10 7 cells/mL. There were no significant differences among the infective structures in the two tested variables. However, there were significant differences among the LC50's with different infective structures within the same B. bassiana isolate. Three fungicide formulations and 24 insecticides and/or mitecides were compatible with B. bassiana including those with the following active ingredients: propamocarb hydrochloride, sulphur, abamectin, acephate,acetamiprid, betacyfluthrin, bifenthrin, cyromazine, deltamethrin, diafentiuron, diflubenzuron, dimethoate, fenpropathrin, fenpyroximate, fenvalerate, imidacloprid, methamidophos, propargite, tebufenozide and trichlorfon. There was large variability in the toxicity of products withing a chemical group and products containing the same active ingredient. B. bassiana was an efficient T. urticae mite control in chrysanthemum (Dendranthema grandiflora), when applied at a concentration of 2x10 8 conidia/mL. Microbial control was better than that provided by chemical pesticides normally used in the greenhouses. With four fungal sprays within 14 days, the mite density was reduced from 1.8 to 0.1 mite/leaf. In strawberry (Fragaria sp.), T. urticae control was lower than in chrysanthemum, with mean density of mites for 21 days after application of 1x10 8 or 5x10 7 conidia/mL at 13 mites/leaflet, compared to 43 mites/leaflet in control plots. The strawberry varieties 'Campinas' and 'Princesa Isabel' had the lowest mite densities, however, these varieties did not affect the efficacy of mite control by B. bassiana. Thus, M. anisopliae, B. bassiana and Hirsutella sp. were the most promissing fungi to be formulated as mycomiticides for T. urticae control.

No description available.

The distribution of wild biodiversity in agroecosystems affect crop performance and yield in various ways. In this thesis I have studied the impact of wild biodiversity, in terms of trees and forest structures, on crop pests, pollinators and the pollination services provided in a heterogeneous landscape in southwestern Ethiopia.  Coffee, Coffea arabica, is a forest shrub native to Ethiopia and is grown in most wooded areas in the landscape where I conducted my studies. Wild coffee is still found in remote parts of the forests in the landscape. For my first paper, I surveyed pest damage on coffee in coffee forest sites, where some sites were situated in continuous forest and some in isolated forest patches. I found the variation in pest damage frequency to mainly be among coffee plants within a site, rather than among sites, which indicates the importance of local processes. However, some pests were clearly connected to the forest habitat, such as the olive baboon. In my second study, I surveyed pollinators visiting coffee flowers across a gradient of shade-tree structures. I found the semi-wild honeybee to be the dominating flower visitor. The abundance of the honeybee was not related to shade-tree structures, but to amount of coffee flower resources in the site. On the other hand, other pollinators, which included other bee species and hoverflies, were positively affected by more shade trees in the site. In my third study I investigated how the forest cover affected local bee communities in the agricultural landscape. Moreover, I investigated if this relationship differed between the dry and rainy season. The distribution of food resources for bees changes between the seasons, which may affect the bees. Most trees, fruit trees and coffee, which are patchy resources, flowers in the dry season, whereas most herbs and annual crops, which are more evenly spread resources, flowers during the rainy season. I found a clear turnover in bee species composition between the dry and rainy season, with more mobile species in the dry season. Increased forest cover in the surrounding landscape had a positive impact on bee abundance and species richness. However, the impact did not change between seasons. In my fourth study I evaluated the pollination success and pollen limitation of a common oil crop in the landscape in relation to forest cover. I found severe pollen limitation across the landscape, which may be related to the observed low bee abundances. The pollen limitation was not related to surrounding forest cover. In conclusion, I have found the forest and wooded habitats to impact several mobile animals and pathogens in our study landscape, which in turn affect people. However, there is large complexity in nature and general relationships between forest structures and all crop related organisms may be unlikely to find. Various species are dependent on different resources, at different spatial scales and are interacting with several other species. To develop management strategies for increased pollination services, for reduced pest damage or for conservation in the landscape, more species-specific knowledge is needed. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>