In Mozambique, establishment of aquatic weeds has been enhanced through the increased enrichment of water bodies by nutrient runoffs from human and agricultural wastes that lead to an increase in nitrate and phosphate in the water. The aquatic weeds, water hyacinth (Eichhornia crassipes), red water fern ( Azolla microphylla), water lettuce (Pistia stratiotes) and salvinia (Salvinia molesta) were found in most watercourses in Mozambique and are becoming aggressive in some watercourses, especially in the Umbeluzi and Incomati rivers. Farmers and people living along the rivers are aware of the negative impact of the water weeds because the large mats of weeds cause loss of shoreline and navigability along the rivers. Other commonly perceived effects of aquatic invasive plants in Mozambique rivers include: reduced navigable surface area; difficulties for fishermen, which reduces income; increased prevalence of insects and insect-borne disease, and decreased aesthetic value. The methods currently used for the control and management of the aquatic weeds are mechanical and manual control. Both methods are costly, time consuming, and only provide a short-term solution to the problem. The study found that the weevils Neochetina eichhorniae and N. bruchi were effective biological control agents in the study area but their impact is too gradual compared to the aggressive proliferation of water hyacinth. The one year lab-experiment clearly demonstrated that the water lettuce weed had a significant impact on the recruitment of macro-invertebrates to the artificial substrates, and water lettuce contributed to the reduction of oxygen in the water and consequent reduction of macro-invertebrate abundance and diversity. The biodiversity recovered at the same time in the pools containing water lettuce controlled by N. affinis and water lettuce controlled by herbicide, but richness and diversity of macro-invertebrates was higher in the water lettuce controlled by N affinis during the first sampling occasion compared to the water lettuce in pools controlled by herbicide, where macro-invertebrates increased only when DO levels recovered after water lettuce mat decay. The number of taxa recorded in this study is an indication of the significance of macro-invertebrates in an aquatic environment. This therefore emphasizes the need for more research efforts into macrophyte and macro-invertebrate associations in the aquatic system to better understand the implications of habitat modification arising from human activities. It will also enable us to be better equipped with a more appropriate ecological understanding for aquatic resources management.

A highly variable invasive shrub, Lantana camara L. (Verbenaceae), has been notoriously difficult to control thus far despite a well established biological control programme in South Africa. A promising leaf-feeding biological control agent, Falconia intermedia (Distant) (Hemiptera: Miridae), released to control this invasive plant eventually crashed at three out of five sites in the Eastern Cape Province. In the Mpumalanga Province, after initially colonising and building up high numbers on the L. camara stands the agent populations crashed. Several reasons for these population crashes have been suggested, but induced plant defences have not been investigated. Although plants face the challenge of herbivory by various organisms while remaining immobile, some plants may possess the ability to induce physical and/or chemical defensive responses following feeding and thus prevent further plant tissue damage and loss. Laboratory trials were conducted to determine the existence, nature and effect of physical and chemical feeding-induced responses of L. camara on the performance of the leaf-feeding biological control agent, F. intermedia. Lantana camara plants used in the study were obtained from five localities in the Eastern Cape Province, South Africa, while the insect culture was established from field populations. Plants from all varieties on which F. intermedia was released significantly increased the toughness of their leaves compared to control treatment plants. In addition, plants from three localities: Lyndhurst Farm, East London and Port Alfred, significantly increased trichome density after prolonged feeding by F. intermedia. On the three varieties showing increases in these two factors (i.e. leaf toughness and trichome density), oviposition, survival and feeding damage by the mirid agent was significantly lower on previously damaged plants. A significant negative correlation between trichome density and population numbers was found (R²= 0.52, p < 0.0003), suggesting that an increase in trichome density strongly contributes to a reduction in F. intermedia's growth. The growth and reproduction of the resistant plants was not significantly impacted by F. intermedia feeding. The defensive responses were found to be plant systemic and rapidly induced as they were elicited and expressed throughout the plant in both damaged and undamaged leaves within five weeks after insect release. Leaf toughness and trichome density were not significantly increased after feeding on plants from Whitney Farm and Heather Glen Farm. On the contrary, mirid individuals performed significantly better on plants from Whitney Farm and Heather Glen Farm than on plants of other varieties, indicating their susceptibility and suitability to the agent and the lack of induced resistance against the agent. Plants from all localities besides East London showed some level of tolerance and overcompensated for feeding damage by increasing plant growth and reproductive factors on plants fed upon. This was however only significant in two variables of the more susceptible localities, Whitney Farm and Heather Glen Farm. This increase in plant fitness did however indicate an induced defence response by these plants to feeding, a response designed to lessen the effects of agent feeding. Headspace volatile analysis was used to investigate any volatile chemical responses by L. camara due to F. intermedia feeding at two of the five localities chosen: East London and Whitney Farm. There was no significant difference in headspace volatiles emitted by leaves of plants from the East London insect infested and control treatment plants. On the Whitney Farm damaged plants however there was a 2.5 fold increase in the emission intensity of one of the three main compounds, later identified as Beta-caryophyllene. Three major chemical constituents which were found to be common to leaf volatiles of the two varieties were identified through gas chromatography-mass spectrometry (GC-MS) from the damaged and undamaged leaves of these two varieties. The methods used in collecting leaf volatiles were shown to be significant in the strength of chromatogram peaks. Using general authentication methods and purified standards, one of these was identified as the sesquiterpene, Beta-caryophyllene (C₁₅H₂₄). This compound is one of the major constituents found in isolations of L. camara varieties worldwide. This is the first such work done on a variety of L. camara in South Africa, and hopefully the beginning of more in-depth studies of the volatile organic chemicals from the numerous naturalised varieties of L. camara. It is suggested that the sum of these responses may play a role bigger than is currently understood in this plant-insect relationship. It is also argued that feeding induced plant defences may play an important role in attempts to control alien plants using insect agents.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-18T11:32:10Z No. of bitstreams: 1 ELVIRA BEZERRA PESSOA - TESE PPGEA 2012..pdf: 49929920 bytes, checksum: 3b211bebb087afcfef048700e63d31fb (MD5) / Made available in DSpace on 2018-06-18T11:32:10Z (GMT). No. of bitstreams: 1 ELVIRA BEZERRA PESSOA - TESE PPGEA 2012..pdf: 49929920 bytes, checksum: 3b211bebb087afcfef048700e63d31fb (MD5) Previous issue date: 2012-04 / Dentre as pragas que atacam as sementes de feijão durante o armazenamento, destaca-se o Zabrotes subfasciatus (gorgulho-do-feijão) por reduzir a qualidade e o valor nutricional das sementes. A redução da qualidade dos grãos/sementes durante o armazenamento está associada, principalmente, ao grau de infestação e às condições ambientais cm que se encontra a massa de feijão. Assim, buscou-se com este trabalho produzir e avaliar o potencial de extratos vegetais de Aspidosperma pyrifolium (pereiro), Anadenanthera colubrina (angico) e Licania rígida (oiticica) no controle do Zabrotes subjàsciatus, bem como avaliar a qualidade física e fisiológica das sementes de feijão Phaseolus tratadas com extratos, obtidos da folha c da casca dessas espécies, durante 180 dias acondicionadas em embalagens do tipo pet em ambiente não controlado de temperatura e umidade relativa do ar. O trabalho foi realizado cm quatro experimentos, onde no primeiro foram produzidos os extratos e realizados a bbatividade inseticida dos extratos vegetais hidroalcoolico e seco, cm que o extrato pereiro casca a partir da dose de 3 ml, foi 100% eficiente em matar o Zabrotes subfasciatus e, nas doses de 4 e 5 ml a mortalidade de 100% deu-se para todos os extratos. No segundo experimento se estudou a repelência/atralividade e mortalidade do Zabrotes subfasciatus pelos extratos pós das mesmas plantas, tendo-sc observado que o número de insetos adultos repelidos pelos extratos pós tbi maior com o extrato oiticica casca, seguido dos demais (pereiro casca, angico casca, pereiro folha e angico folha) que estatisticamente se igualaram e, o menor número de insetos repelidos deu-se com o extrato oiticica folha, ocorrendo o contrário com a atratividade. Os bioensaios para prospecção lltoquímica dos extratos vegetais obtidos das folhas e das cascas dessas espécies, correspondeu ao terceiro experimento, em que os extratos de pereiro revelaram os mais elevados índices de compostos secundários (alcalóides, esteróides, taninos, flavonóides e saponinas) seguidos de angico e oiticica e, no quarto experimento os extratos botânicos foram utilizados no controle deste inseto praga durante o armazenamento, onde constatou-se atividade inseticida no controle do Zabrotes subfasciatus, matando-os e/ou inibindo o seu desenvolvimento. No tratamento das sementes de feijão Phaseolus, a dose de 3 ml tbi a de melhor controle com melhor resultados para os extratos oiticica folha c pereiro casca. Os procedimentos adotados no tratamento das sementes com os extratos das espécies vegetais demonstraram eficiência na manutenção da viabilidade não afetando a germinação durante os 180 dias do armazenamento. / Among the pests that attack bean seeds during storage, we highlight the 'Zabrotes subfasciatus (bean weevil) by reducing the quality and nutritional value of seeds. lhe reduction of the quality of grains / seeds during storage is mainly associated with the degree of infestai ion and environmental conditions in which it is the mass of beans. Thus. we attempted to produce this work and assess the potential of plant extracts of Aspidosperma pyrifolium (pereiro), Anadenanthera colubrína (angico) and Licania rígida (oiticica) of Zabrotes subfasciatus in control and evaluate the physical and physiological quality of seeds Phaseolus beans treated with extracts obtained from leaves and bark of these species, 180 days packed in like pet under uncontrolled temperature and relative humidity. The study was conducted in four experimenls. where the first extracts werc produccd and performed the bioactivky of insecticide hydroalcoholic plant extracts and dry in the extract from the bark pereiro dose of 3 ml. was 100% effective in killing the Zabrotes subfasciatus and, in doses of 4 and 5 ml 100% mortaliiy are given for ali the extracts. In the second experiment we studied the rcpcllcncy / attractiveness and mortality of Zabrotes subfasciatus post by extracts of these plants and has been observed that the number of adult inseets repelled by the extracts was higher with post myrtle bark extract, followcd by the others (pereiro shcll angico bark, leaf and angico pereiro sheet) that are staiisticaily similar, and the fewer inseets gave repelled with myrtle leaf extract. but the contrary to the attractiveness. The bioassays for phytochemical screening of plant extracts obtained from leaves and bark of these species corresponded to the third experiment, in which extracts pereiro revcaled the highest leveis of secondary compounds (alkaioids, steroids, tannins, flavonoids and saponins) followed by mimosa and myrtle. and lhe fourth experiment, the botanical extracts were used to control this insect pest during storage, where it was found in control insccticidal activity of Zabrotes subfasciatus, killing them and / or inhibiting its development. In the treatment of seeds o f Phaseolus beans, the dose of 3 ml was the best results for better control extracts oiticica, pereiro sheet and the shell. The procedures used in seed treatment with the extracts of plant species were efficient in maintaining the viability did not affect germination during 180 days of storage.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-17T18:15:59Z No. of bitstreams: 1 WHALAMYS LOURENÇO DE ARAÚJO - DISSERTAÇÃO PPGHT 2015..pdf: 998803 bytes, checksum: 00aca588e4e5182e7ebe10263ae94f8c (MD5) / Made available in DSpace on 2018-05-17T18:15:59Z (GMT). No. of bitstreams: 1 WHALAMYS LOURENÇO DE ARAÚJO - DISSERTAÇÃO PPGHT 2015..pdf: 998803 bytes, checksum: 00aca588e4e5182e7ebe10263ae94f8c (MD5) Previous issue date: 2015 / Capes / O cultivo do meloeiro (Cucumis melo L.) é de grande importância para a economia brasileira. Seu cultivo tem demonstrado significativa expansão nas duas últimas décadas, especialmente nas regiões Semiáridas do Nordeste. Apesar dos fatores favoráveis à produtividade do meloeiro, vale salientar fatores limitantes, destacando-se os danos ocasionados por pragas que destroem o cultivo e, consequentemente, diminuindo a colheita, obrigando que medidas de controle sejam adotadas. Entres estas, estão aplicações de inseticidas químicos, entre eles os neonicotinoides. Estudos têm demonstrado os danos colaterais destes inseticidas a insetos benéficos como abelhas, que por sua vez são de fundamental importância para a polinização de 90% das angiospermas, principalmente para o melão. Este trabalho teve como objetivo avaliar a toxicidade de neonicotinoides empregados para o controle de pragas na cultura do meloeiro à abelhas A. mellifera Linnaeus. Os bioensaios foram realizados em laboratório, sendo tomadas medidas repetidas no tempo de mortalidade para os produtos comerciais Actara 250 WG (tiametoxam), Evidence 700 WG (imidacloprid), Mospilan (acetamipride) e Orfeu (acetamipride). A exposição das abelhas aos compostos foi realizada por meio de pulverização e ingestão de alimento contaminado com as maiores e menores doses recomendadas pelos fabricantes. Independente do modo de exposição, tiametoxam, imidaclopride e acetamipride (duas formulações) foram tóxicos, diminuindo o tempo de vida útil das abelhas em até 1, 2, 11 e 11 dias, respectivamente, quando comparados com a testemunha, que por sua vez sobreviveram 18 dias, em média. O inseticida tiametoxam foi extremamente tóxico quando pulverizado sobre as abelhas, bem como quando contaminante da dieta ingerida. O imidaclopride também apresentou toxicidade em ambos os experimentos, sendo depois do tiametoxam o mais tóxicos. O inseticida acetamipride apresentou toxicidade, porém não tão alta, quanto às observadas com o tiametoxam e o imidaclopride. / The cultivation of melon (Cucumis melo L.) is of great importance for the Brazilian economy, especially in semiarid regions of the Northeast. Despite the favorable factors to the yield of melon other limiting factors have been highlighted as the damage caused by pests, which undertake to harvest, requiring that control measures are adopted. Among these are applications of chemical insecticides, including the neonicotinoids. Studies have shown the collateral damage of these insecticides to beneficial insects like bees, important pollinators of 90% of angiosperms, mainly to melon. The objective of this study was to evaluate the toxicity of neonicotinoids used for pest control in the melon crop to Linnaeus honeybees. Bioassays were performed in the laboratory, being taken repeated measures in time to mortality commercial products Actara 250 WG (thiamethoxam), Evidence 700 WG (imidacloprid), Mospilan (acetamiprid) and Orpheus (acetamiprid) (two formulations). The exposure of bees to the compounds was performed by spraying and ingestion of food contaminated with higher and lower doses recommended by the manufacturers. Regardless of the exposure mode, all insecticides were toxic, reducing the useful life of bees within 1, 2 and 11 days, respectively, compared with the control (distilled water + pure candy), which survived 18 days, average . The insecticide thiamethoxam in both experiments and doses, was extremely toxic; as well as Imidacloprid, the second most toxic. The Acetamiprid insecticide, in both formulations showed toxicity, but not so high as those observed with other insecticides in the study.

La lutte contre les rongeurs est souvent un enjeu majeur dans les agroécosystèmes. Nous avons conduit une étude comparative dans des plantations de palmiers à huile dans les provinces de Riau et de Bangka en Indonésie. Dans les deux zones, des chouettes ont été introduites pour la lutte contre les rats ; toutefois, à Riau les rats sont maintenus à des niveaux de population acceptables sans recours au raticide, tandis qu’à Bangka les dégâts des rats sont très importants et l’usage de raticide intensif. Nous avons comparé ce deux systèmes en terme d’abondance et/ou de régime alimentaire de deux prédateurs, chouettes et petits carnivores. D’après nos résultats, les petits carnivores sont beaucoup plus abondants dans les plantations à Riau qu’à Bangka, et le chat léopard (Prionailurus bengalensis) est absent à Bangka tandis que cette espèce domine à Riau. Nos résultats suggèrent également que la prédation sur les rats par les chouettes et les petits carnivores serait moindre à Bangka qu’à Riau. D’une manière générale, cette étude confirme l’hypothèse selon laquelle les petits carnivores, notamment les chats léopard, joueraient un rôle important dans la lutte contre les rats en palmeraies. Par ailleurs, nous avons analysé la distribution spatiale des petits carnivores en plantation. Nos résultats suggèrent que, bien que l’habitat palmeraie soit largement utilisé la nuit par certains petits carnivores comme le chat leopard, qui y trouve une abondante ressource alimentaire, la plupart des espèces sont dépendantes de la forêt. Les gestionnaires des palmeraies devraient adapter leurs pratiques, afin de favoriser les petits carnivores dans une perspective de lutte contre les rats. / Rodent pest control is often a major issue in agroecosystems. We conducted a 3-year comparative study (2010-2012) in oil palm plantations in Riau and Bangka provinces, in Indonesia: in both areas barn owls have been introduced for rat control, and were at least as abundant in Bangka plantations than in Riau, but in Riau rat populations have been maintained at an acceptable level without the use of rodenticide, whereas in Bangka intensive rodenticide applications did not prevent high levels of rat damage. We compared these two contrasting systems in terms of predator community (barn owls and small carnivores) abundance and/or diet. We found that small carnivores were much more abundant in Riau plantations than in Bangka, and that the leopard cat (Prionailurus bengalensis) was the dominant species in Riau while absent from Bangka. Our results on diet suggested that rat prey intake from barn owls and from the small carnivore community would be less in Bangka plantations than in Riau. Broadly, our results suggest that small carnivores, notably the leopard cat, play an important role in rodent control. In addition, we investigated spatial distribution of small carnivores within the oil palm habitat. Our results support the hypothesis that, although the oil palm may be habitable for some small carnivore species such as the leopard cat, where they supposedly forage at night, most species still need forest for their survival in oil palm landscapes. Oil palm plantations managers should adapt agricultural practices and land-use to enhance small carnivores, with the view to improve rodent control.

La rotation de cultures peut être utilisée pour empêcher la sélection continue d’espèces adventices adaptées à un type de culture. Elle pourrait favoriser la gestion des adventices, l’économie d’herbicides et la biodiversité. Les successions de cultures simples d’aujourd’hui pourraient être diversifiées par des cultures fourragères pérennes. Les impacts des ces cultures sur les adventices ont été étudié utilisant quatre approches : 1) Des relevés d’adventices sur 632 champs dans l’ouest de la France ont montré que la composition spécifique varie le plus entre des cultures fourragères pérennes et des cultures annuelles. Une comparaison des champs avant, pendant, et après des cultures fourragères pérennes a suggéré que la composition des communautés varie d’une manière cyclique pendant ces rotations. Plusieurs espèces problématiques dans des cultures annuelles ont été supprimées pendant et après les cultures pérennes, mais l’apparition d’autres espèces a produit une diversité de plantes comparable, voire supérieure. 2) Une expérimentation au champ de trois ans avec des modes de gestion contrastés a permis d’étudier les mécanismes sous-jacents: L’absence de travail du sol a réduit la levée des adventices, mais a augmenté la survie des plantes adultes. Le couvert végétal permanent et les fauches fréquentes ont réduit la croissance, la survie des plantes et la production de graines. 3) Des expérimentations sous serre analysant la croissance poste fauche de plantes individuelles ont montré des différences importantes entre espèces et groupes fonctionnels. Une expérimentation à deux facteurs a suggéré que les impacts négatifs de la fauche et de la compétition sur la croissance des adventices ont été additifs. 4) Des mesures spéciales de prédation de graines d’adventices sur l’expérimentation au champ ont montré des corrélations positives avec le couvert végétal et la prédation, indiquant une importance particulière de ce service écosystémique dans des cultures pérennes. La préférence des graines de certaines espèces montre que la prédation de graines peut être une autre cause des changements de communautés d’adventices. / Crop rotation may be used to prevent the continuous selection of particular weed species adapted to one crop type. This might be useful for weed management, economy in herbicide applications and promoting biodiversity. Common simple crop sequences might be diversified by introducing perennial forage crops. Impacts of such perennial crops on weeds were studied with four approaches : 1) Large-scale weed surveys in 632 fields in western France showed that weed species composition differed most strongly between perennial alfalfa crops and annual crops. Comparisons of fields before, during and after perennial alfalfa suggested that community composition varies in a cyclic way during such crop rotations. Several weed species problematic in annual crops were suppressed during and after perennial crops, but the appearance of other species led to equal or even higher plant diversities. 2) A 3-year field experiment with contrasting crop management options allowed an investigation of the underlying mechanisms for this: The absence of soil tillage reduced weed emergence but increased the survival of established plants. The permanent vegetation cover and frequent hay cuttings reduced weed growth, plant survival and seed production. 3) Greenhouse experiments testing the regrowth ability of individual plants after cutting showed strong differences between species and functional groups. An two-factorial experiment suggested that the negative impacts of cutting and competition on weed growth were mainly additive. 4) Special measurements of weed seed predation in the field experiment showed positive correlations with vegetation cover, indicating that this ecosystem service may be particularly fostered by perennial crops. Consistent preferences of seed predators for certain weed species indicates that seed predation may be another cause of the observed weed community shifts. / Fruchtfolgen können dazu dienen, die kontinuierliche Selektion von Unkrautarten zu verhindern, die an eine bestimmte Kultur angepasst sind. Dies könnte dem Unkrautmanagement, der Einsparung von Herbiziden, und der Biodiversität dienen. Heutige, sehr einfache Furchtfolgen könnten durch mehrjährige Futterkulturen diversifiziert werden. Die Einflüsse solcher mehrjähriger Kulturen auf Unkräuter wurden in vier Ansätzen untersucht : 1) Vegetationsaufnahmen auf 632 Feldern in Westfrankreich zeigten, dass die Unkrautzusammensetzung zwischen mehrjährigen Futterkulturen und einjährigen Kulturen stark variiert. Der Vergleich von Feldern vor, während und nach mehrjährigen Futterkulturen legte nahe, dass die Pflanzengemeinschaft während solcher Fruchtfolgen zyklisch variiert. Mehrere problematische Unkrautarten wurden während und nach den mehrjährigen Kulturen zurückgedrängt. Das Auftauchen anderer Arten führte jedoch zu einer gleichbleibenden oder leicht erhöhten Pflanzenvielfalt. 2) Ein dreijähriger Feldversuch mit verschiedenen Bearbeitungsoptionen ermöglichte es, die zugrunde liegenden Mechanismen zu untersuchen: Die fehlende Bodenbearbeitung hat das Auflaufen der Unkräuter reduziert und das Überleben der adulten Pflanzen erhöht. Die permanente Vegetationsbedeckung und die häufigen Heuschnitte haben das Wachstum, das Überleben und die Samenproduktion vermindert. 3) Gewächshausexperimente zum Nachwachsen von Unkrautpflanzen nach Heuschnitten zeigten große Unterschiede zwischen verschiedenen Arten und funktionellen Gruppen. Ein Experiment mit zwei Faktoren lässt vermuten, dass die negativen Effekte der Schnitte und der Konkurrenz auf das Unkrautwachstum sich addieren. 4) Spezielle Messungen der Prädation von Unkrautsamen auf den untersuchten Feldern zeigten positive Korrelationen mit der Vegetationsbedeckung, was auf eine besondere Wichtigkeit dieser Ökosystemdienstleistung in ausdauernden Kulturen hindeutet. Die Präferenz von bestimmten Samenarten deutet darauf hin, dass Samenprädation ein weiterer Grund für die beobachteten Änderungen der Unkrautgemeinschaften sein kann.

PhD (Zoology) / Department of Zoology / An ever growing human population and accelerating land use change is associated with the loss of species and their ecosystem services. Agricultural intensification has led to a worldwide threat of extinction to about one quarter of all bat species, despite the valuable ecosystem service of pest control provided by bats. The decline in bat populations is mainly attributed to the loss or fragmentation of habitats, roost sites and feeding opportunities related to agricultural intensification and land use change. Therefore, proactive management of bat communities in agricultural landscapes is essential. South Africa is the world’s largest producer of macadamias and the industry continues to grow. This study gains insight into the habitat use and foraging behaviour of insectivorous bat species on a temporal and spatial scale, in and around macadamia orchards in order to advise management strategies on how to increase bat activity and, possibly, pest control. It also focuses on the preferences of artificial roost sites used by insectivorous bats in macadamia orchards. The diet of insectivorous bat species is especially difficult to study and the least invasive tool to gain information is the study of bat faecal pellets. In order to provide evidence for the consumption of pest insect species by bats and thus incentive to farmers for a more integrated pest management approach (IPM), this study explored molecular approach to insectivorous bat diet analyses using fragment analysis of bat faecal pellets with fluorescent-labelled species-specific primers (designed for the CO I gene). This study was conducted in the subtropical fruit growing area of Levubu, Limpopo province, South Africa between the towns Thohoyandou (22°59'03.7 S, 30°27'12.8 E) and Makhado/Louis Trichardt (23°03'03.6 S, 29°55'12.7 E). Levubu also accounts for the second highest production of macadamia in South Africa. An introduction to the order Chiroptera and into the relevance of insectivorous bat species to agriculture as well as the importance of a more integrated pest management approach (IPM) focusing on bats is provided in Chapter One. Bats were acoustically monitored and light traps were used to catch arthropods during one annual cycle. I sampled five macadamia orchards once a month from September 2015 to August 2016 and used GIS and R to analyse both the general bat activity and foraging bat activity of the two main foraging guilds (open-air/clutter edge guild) in different land use types as well as total bat activity with respect to arthropod abundances. As reported in Chapter Two, results show that the overall clutter edge guild activity (number of passes) decreased with macadamia and orchard (all other fruit) cover in the macadamia high season (December to end of May) and increased with bush cover and distance to settlements (potential roosts) in the macadamia low season (June to end of November). Open-air guild activity increased with fallow cover (uncultivated grassland with scattered trees and shrubs) in the high season. Foraging activity (feeding buzzes) of the clutter edge guild increased with bush cover over the whole year. Total activity (both guilds) increased with abundance of true bugs (Hemiptera), including the main macadamia pests, and bush cover. Macadamia cover has a negative effect on the activity of the clutter edge guild in the high season, with low activity in the orchard center (high cover), and activity increasing in a linear way with decreasing orchard cover at the orchard edge (low cover). These results suggest that the clutter edge guild prefers foraging close to the edges of the orchards rather than in the center, while the open-air guild prefers semi-natural habitats (fallow). When numbers of pest arthropods drop in the macadamia orchards, the natural land use type, bush, becomes a more important foraging habitat and thereby increased the activity of the clutter edge guild. From June 2016 to July 2017, I scanned 31 bat houses, mounted on poles on six macadamia orchards, for bats or any other occupants such as wasps, birds and bees. Twenty-one multichambered bat houses of three slightly different chamber designs were erected on poles, in sets of three. Additionally, five bat houses of the type ‘Rocket box’, four bat houses in sets of two (black and white) and one colony bat house were erected. Bats were counted and visually identified to family or species level. From December 2016 to end of March 2017, three IButtons were installed to record temperature variation between one set of three bat houses. As reported in Chapter Three, results show that the central bat house in the set of three and the black bat house in the set of two had a significantly positive effect on bat house occupancy. There was a significant difference in the mean temperature between the houses in the set of three, with a significant difference in temperature of 0.46°C between the central and the first bat house. The three bat houses erected in sets varied slightly in their chamber design, with the central bathouse having the most chambers (six), while the bat houses to either side had less chambers (four), set at an angle or straight. This and the insulation to either side by the other bat houses is assumingly what caused the central bat house to be on average warmer. The Yellow-bellied house bat (Scotophilus dinganii) was by far the most recorded and the only species observed to co-habitat a bat house with another animal species, in particular honeybees. The study might confirm assumptions in that the microclimate of bat houses, respectively their insulation, sun exposure and color appear to be important factors influencing bat house occupancy. The two preferred bat houses in our study were the black, in the set of black and white, as well as the central, and on average warmest bat house, in the set of three. I collected bat faecal pellets with two different methods between July 2015 and April 2017 to determine the prevalence of pest insects in faecal pellets. Eighteen of the bat houses (in sets of three) on three different farms and two Egyptian slit-faced bat (Nycteris thebaica) roosts were fitted with trays in order to collect pellets from those occupied by bats. I noted occupancy of bat houses to species or family level to keep disturbance minimal. Additionally, I collected pellets from individuals captured by means of mist nets and harp traps. Four of the main pest-insects; the two-spotted stinkbug (Pentatomidae: Bathycoelia distincta), the green vegetable bug (Pentatomidae: Nezara viridula), the macadamia nut borer (Tortricidae: Thaumatotibia batrachopa) and the litchi moth (Tortricidae: Cryptophlebia peltastica), were collected from pheromone traps or after scouting for primer development and optimisation. After extracting DNA from the bat faecal samples the target regions were amplified in a multiplex PCR and fluorescently labelled PCR amplicons were analysed and interpreted. In order to verify multiplex analyses results, all samples were amplified with all four sets of primers in plates and those that produced amplicons were purified and sequenced. As reported in Chapter Four, results show that fragment analyses yielded a total of 63 out of 103 samples tested positive for pest insect species (61%) with a total of 92 positive fragments. Primer specificity could be confirmed to 100% for the sequences obtained for Bathycoelia distincta (26/26) and Nezara viridula (12/12) primers but not for all sequences obtained fot Cryptophlebia peltastica (18/30) and Thaumatotibia batrachopa (1/14) primers. One sample showed no positive fragments but contained a positive sequence for N. viridula. Three samples tested positive for one pest-species fragment but contained a positive sequence for a second pest-species (B. distincta, T. batrachopa and C. peltastica). Adding four positive fragments and one additional positive sequence to the data. This means that sequences of pest insect species were obtained from 54 out of the 103 samples (55.6%) with a total of 73 pest insect sequences. For the high season (December to end of May) a total of 37 positive fragments for the four pest insect species and 24 negative samples were yielded and for the a low season (June to end of November) a total of 36 positive fragments and 15 negative samples. Looking at the pest consumption of the different bat species or families, our results show that all of them foraged on pest insect species. Whereas, all species and families except Myotis bocagii and Rhinolophus simulator (for which N<2) foraged on both the Lepidopteran and Hemipteran pest species. Therefore, all families of bats of which faecal pellets were analysed for this study (Molossidae, Nycteridae, Rhinolophidae and Vespertilionidae) foraged on one or more of the four pest insect species. In summary, Chapter Five concludes that natural and semi-natural vegetation promote bat activity in macadamia orchards, and potentially bats' provision of the ecosystem service of pest control. In times of accelerating land use change, remnants of natural vegetation are important refuges and need to be maintained or restored to conserve bat species and promote their ecosystem services. The study also shows that bat activity might be improved by adding roosting opportunities to orchards. Warm and well-insulated bat houses mounted freestanding on poles and in sets appeared to work best in northern South Africa. Further research on co-habitation of bat houses and displacement behaviour as well as the potential importance of altitude and distance to water is needed. All of the species or families of bats from which faecal pellets were collected have been confirmed to forage on at least one of the four pest insects and the bat species have shown to be much more generalist and presumably opportunistic feeders than previously assumed. Thus, this study provides incentive and advice to farmers for a more integrated pest management approach (IPM). / NRF

This thesis discusses the responsibility of and risk for infestations of spruce bark beetle. The spruce bark beetle, Ips typographus, is a natural part of the Swedish forest ecosystem but causes severe financial damage in forestry. Since 2018, the spruce bark beetle infestations have been substantial in Sweden. The first task of the thesis is to evaluate the balance between the forest production interests and the environmental interests, based on the legal regulation of spruce bark beetle control. Production and environment are the equal aims of the Swedish Forestry Act. The regulation of spruce bark beetle control differs depending on whether the forest is in a conservation area or not. For example, owners of forests outside conservation areas are obliged to take care of damaged, fresh wood of spruce and pine, while such an obligation in general does not exist in conservation areas. In this evaluation, I conclude that the balance between the two interests in the spruce bark beetle regulation is good as a whole.  The second question of the thesis is the legal allocation of risk for spruce bark beetle infestations. In this investigation, it is examined whether established law presents a possibility to claim damages for spruce bark beetle infestations that may derive from an adjacent forest. The conclusion drawn is that the regulation of compensation for certain kinds of environmental damage in the Swedish Environmental Code probably would not be applicable as a legal basis for such a claim. By contrast, neighbour law and the Swedish Torts Act could be used as the basis of an action for damages. However, to prove causality regarding the origins of a specific infestation might bring problems, which altogether means that an action for damages faces considerable difficulties. Therefore lastly, some alternative ways of allocating the risk for spruce bark beetle infestations are presented. / I denna uppsats diskuteras ansvar och risk för granbarkborreangrepp. Granbarkborren, Ips typographus, är en naturlig del av skogens ekosystem men orsakar stora ekonomiska skador i skogsbruket. Sedan 2018 har granbarkborreangreppen i Sverige varit omfattande.  Uppsatsens första uppgift är att utifrån regleringen av granbarkborrebekämpning i skogen utvärdera avvägningen mellan produktions- och miljöintresset, som är skogsvårdslagens jämställda mål. Den rättsliga regleringen av bekämpning av granbarkborrar skiljer sig åt beroende på om skogen är skyddad eller oskyddad. Bland annat är ägare av oskyddad skog ålagda att ta hand om skadat, färskt barrvirke, medan en sådan skyldighet ofta saknas i skyddade områden. I utvärderingen kommer jag fram till att avvägningen mellan de två intressena över lag är god i granbarkborreregleringen.  Den andra frågan i uppsatsen är fördelningen av risk för granbarkborreangrepp. För att undersöka det utreds om det enligt gällande rätt är möjligt att få skadestånd för granbarkborreangrepp som kan härstamma från närliggande skyddad eller oskyddad skog. Slutsatsen är att 32 kap. miljöbalken förmodligen inte skulle vara tillämplig, medan däremot grannelagsrätten och skadeståndslagen kan läggas till grund för en sådan talan. Att bevisa orsakssambanden kan dock innebära problem, vilket sammantaget gör att en skadeståndstalan för granbarkborreangrepp från närliggande skog möter ansenliga hinder. Sist presenteras därför några alternativa sätt att fördela risken för barkborreangrepp.

El objetivo de esta Tesis Doctoral es estudiar diferentes herramientas para el manejo de plagas y enfermedades del cultivo de la platanera. Entre las herramientas que vamos a desarrollar, se van a analizar los compuestos orgánicos volátiles (COVs) fúngicos derivados de hongos entomopatógenos (HE) y nematófagos, como fuente de metabolitos con actividad antagónica contra el picudo negro (PN) de la platanera, Cosmopolites sordidus, para su control y manejo en el campo. Así mismo, vamos a estudiar las respuestas de cultivares de plataneras a quitosano, un polisacárido biodegradable, para evaluar su posible uso en el campo como estimulante y protector de las plantas frente a plagas y patógenos, como Fusarium oxysporum f. sp. cubense. El conjunto de capítulos de esta tesis pretende sentar las bases de una estrategia de manejo sostenible de plagas y enfermedades del cultivo de la platanera, basada en el uso de COVs derivados de hongos presentes de forma natural en los cultivos, en combinación con la suplementación de quitosano en el riego, para un efecto de protección y activación de las defensas de las plataneras antes de cualquier infección de plagas y/o enfermedades. El objetivo principal de esta Tesis Doctoral es encontrar nuevas fórmulas para la gestión integrada de plagas como Cosmopolites sordidus y enfermedades de la platanera en condiciones de campo. En esta Tesis Doctoral hemos ideado enfoques sostenibles para la gestión de las plagas y enfermedades de las plataneras. Nuestros objetivos son: a) Cosmopolites sordidus (picudo negro de la platanera, PN), la principal plaga de los cultivos de plátano y, b) el hongo del marchitamiento Fusarium oxysporum f. sp. cubense Raza Tropical 4 (FocTR4), agente causante de una nueva variante extremadamente virulenta de la enfermedad del “Mal de Panamá”, que se está extendiendo rápidamente por todo el mundo. Nuestras herramientas de gestión sostenible son: a) los hongos entomopatógenos (HE, conocidos por su uso como agentes de control biológico, ACBs) aislados de campos comerciales de plátanos, b) sus compuestos orgánicos volátiles (COVs) y, c) el quitosano, un compuesto biodegradable y elicitor de la inmunidad de las plantas con actividad antimicrobiana. Damos evidencia de que los COVs de los hongos agentes de control biológico son repelentes del PN. Pueden utilizarse en los cultivos de platanera mediante estrategias de push and pull para gestionar la plaga de forma sostenible. El quitosano puede utilizarse en el riego para prevenir las defensas de la platanera local y sistémicamente. Por lo tanto, este polímero, con probada actividad antimicrobiana frente a otros patógenos de marchitamiento de Fusarium spp., podría utilizarse contra la actual pandemia en las plataneras causada por FocTR4. La capacidad de inducir reguladores del crecimiento de las plantas sostiene también el papel fertilizante del quitosano. La inducción de compuestos relacionados con la respuesta sistémica adquirida (RSA) hace que el riego con quitosano sea una herramienta para manejar también las plagas de las plataneras sobre el suelo (PN) y las enfermedades (Sigatoka). De esta manera, los COVs y el quitosano podrían ayudar a reducir el uso de agroquímicos tóxicos en los cultivos de platanera en todo el mundo.

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