Made available in DSpace on 2017-07-10T15:14:26Z (GMT). No. of bitstreams: 1 Dissertacao_Cattaneo.pdf: 561766 bytes, checksum: 799e4a531c12c6339682bf2b62bd5254 (MD5) Previous issue date: 2015-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The crambe (Crambe abyssinica) is an oilseed crop belonging to the family of crucifers, which has good adaptability and hardiness and can be an alternative for the production of biodiesel. However, the occurrence of diseases might be a limiting factor for production. The objective of this study was to evaluate the effectiveness of seed treatment to control pathogens crambe seed, vigor analysis (size and fresh and dry weight) of seedlings, yield components and grain yield, using two biological products and three chemicals. The experimental design was completely randomized with six seed treatments (T0 - control; T1 - Trichoderma asperellum, T2 - Bacillus subtilis, T3 - glutamic acid, seaweed extract (Ascophillum nodosum), cobalt, molybdenum and manganese, T4 - thiamethoxam; T5 - zinc). Treatments when tested in the laboratory, resulted in no increase in the percentage of seed germination, although the treatments with T. asperellum and B. subtilis reduced the size of seedlings. In the field, yield components, except for the height and weight of 1000 grains were positively influenced by seed treatments. The chemical and biological treatments had suppressive effect of pathogens contained in the seeds, what can be an alternative for the control of pathogens in seeds of crambe, however, when they were tested in the field, only the treatments based on T. asperellum and B. subtilis and thiamethoxam resulted in increased productivity / O crambe (Crambe abyssinica) é uma cultura oleaginosa pertencente à família das crucíferas, que possui boa adaptação e rusticidade e pode ser uma alternativa para a produção de biodiesel. Porém, a ocorrência de doenças pode ser um fator limitante para a produção. O objetivo deste trabalho foi avaliar a eficácia do tratamento de sementes de crambe no controle de patógenos da semente, análise de vigor (tamanho e massas fresca e seca) das plântulas, componentes de produção e produtividade de grãos, utilizando dois produtos biológicos e três produtos químicos. O delineamento experimental foi inteiramente casualizado com seis tratamentos de semente (T0 Testemunha; T1 Trichoderma asperellum; T2 Bacillus subtilis; T3 ácido glutâmico, extrato de alga (Ascophillum nodosum), cobalto, molibdênio e manganês; T4 tiametoxam; T5 zinco). Os tratamentos quando testados em laboratório, não resultaram em aumento da percentagem de germinação das sementes, porém os tratamentos com T. asperellum e B. subtilis reduziram o tamanho de plântulas. Em campo, os componentes da produção, com exceção da altura e da massa de 1000 grãos foram influenciados positivamente pelos tratamentos de semente. Os tratamentos químico e biológico tiveram efeito supressivo dos patógenos contidos nas sementes, mostrado-se uma alternativa para o controle de patógenos em sementes de crambe, porém, quando estes foram testados a campo, somente os tratamentos a base de T. asperellum, B. subtilis e tiametoxam resultaram em incremento de produtividade.

Orientador: Sérgio de Freitas / Banca: Nelson Wanderley Perioto / Banca: Brígida de Souza / Resumo: O gênero Ceraeochrysa Adams é um dos maiores e amplamente distribuídos do Neotrópico. Muitas de suas espécies têm sido relatadas como importantes controladores biológicos de insetos pragas em culturas. Em Venezuela o estudo dos crisopídeos tem passado despercebido e somente as espécies Ceraeochrysa cubana, C. everes, e C. valida tem relato de ocorrência. Levando em conta esta problemática se realizaram amostragens nos estados Lara (Tarabana), Yaracuy (Aroa, Nirgua), Portuguesa (Las Matas), Barinas (Socopo) e Miranda (Tacata) com o objetivo de fazer um levantamento das espécies de Ceraeochrysa que ocorrem em pomares de Citrus spp., na Venezuela. Os insetos coletados foram coletados com rede entomologia, colocados vivos em garrafas plásticas de 1 Lt de capacidade, levados ao laboratório, congelados, alfinetados e secados. Posteriormente o abdômen foi cortado e macerado em solução de KOH 10% por duas horas, colorado com Clorazol Black, extraída a genitália, fotografada e desenhada com ajuda de microscópio estereoscópico e microscópio biológico, ambos com câmaras lúcidas acopladas. Os exemplares foram identificados comparando as genitálias previas disponíveis em textos e publicações especializadas. Foram identificadas as espécies C. cincta, C. cubana, C. everes e C. valida já relatadas para Venezuela e as espécies C. acmon, C. caligata, C. claveri, C. dislepis, C. montoyana, C. sanchezi, C. scapularis, C squama e C. valida, alem dos exemplares Ceraeochrysa sp1, Ceraeochrysa sp2, Ceraeochrysa sp3 e Ceraeochrysa sp4. Para cada exemplar foram realizadas as redescrições e descrições correspondentes. As redescrições foram justificadas em função das variações intraespecíficas que se observaram, desenhou-se uma chave taxonômica para identificação das espécies e para cada uma delas foram realizadas pranchas de desenhos que mostram os caracteres ressaltantes das espécies estudadas. / Abstract: Ceraeochrysa Adams is one of the largest and widely distributed green lacewing genus. Many species has been related as an important biological control agents of insects pest in agricultural situations. In Venezuela, the study of green lacewings has been passed over and only Ceraeochrysa cubana, C. everes, and C. valida species has been reported. Considering this problem, several sampling in Lara (Tarabana), Yaracuy (Aroa, Nirgua), Portuguesa (Las Matas), Barinas (Socopo) and Miranda (Tacata) states were made intending to make an inventory of Ceraeochrysa species that occur in orchards of Citrus spp. in Venezuela. The insects samples were collected with proper nets, put on plastic bottles, taken to the lab, frozen, pinned and dried. Afterward, the abdomen was cut and macerated in KOH 10% solution by two hours, tinted with clorazol-black and it was made the corresponding analyses to identify the exemplars by comparing their genitals among available specialized essays and publications. It was found C. cincta, C. cubana, C. everes and C. valida species already reported to Venezuela and the species C. acmon, C. caligata, C. claveri, C. dislepis, C. sanchezi, C. scapularis, C. squama, C. montoyana, in addition to exemplars Ceraeochrysa sp1, Ceraeochrysa sp2, Ceraeochrysa sp3 and Ceraeochrysa sp4. For each sample it had been made the re-descriptions and descriptions correspondents. The re-description were justified by the intraspecifics variations that were observed, then a taxonomic key were drawn to indentify the species and, for each of them, were realized model sheets that brings us the standings characteristics of studied species. Further studies will be necessary to use these species in pest management programs. / Mestre

O tomateiro (Lycopersicon esculentum Mill.) figura no cenário mundial como a principal hortaliça em volume industrializado e a segunda atividade hortícola, no que se refere à área cultivada e à importância econômica. A cultura do tomate é conhecida como uma atividade agrícola de alto risco, devido aos graves problemas fitossanitários que ocorrem durante todo seu ciclo. Dentre as principais pragas do tomateiro pode ser citado o ácaro Tetranychus evansi Baker e Pritchard. Este ácaro é encontrado nas Américas, África, Europa e, mais recentemente, na Ásia. No continente africano, esta praga ocasiona perdas de até 90% na produção.T. evansi tem se mostrado uma presa desfavorável para a maioria dos predadores estudados até recentemente. Encontra-se em andamento um projeto de controle biológico com intuito de localizar agentes eficientes para o controle de T. evansi, que possam ser introduzidos no continente africano. As buscas estão sendo realizadas em espécies de Solanaceae em regiões do continente sul americano que apresentam condições climáticas semelhantes às encontradas nos países africanos onde esta praga esta ocorrendo. Os ácaros predadores (Phytoseiidae) encontrados em associação com T. evansi naquelas avaliações foram Phytoseiulus longipes Evans, Phytoseiulus fragariae Denmark e Schicha e Neoseiulus californicus (McGregor), coletadas no município de Uruguaiana, Estado do Rio Grande do Sul. Estudos em laboratório e campo com populações de P. longipes apresentaram resultados bastante promissores no controle de T. evansi Nada se conhece, entretanto em relação ao potencial dos outros dois predadores como agentes de controle daquela praga. O objetivo do presente trabalho foi avaliar o potencial dos predadores P. fragariae e N. californicus, no controle biológico de T. evansi e T. urticae em solanáceas. / Tomato (Lycopersicon esculentum Mill.) is the most important industrialized vegetable crop in the world, and the second horticultural activity in terms of cultivated area and economic importance. The tomato crop is known as an agricultural activity of high risk, due to phytosanitary problems during the entire cycle. Among the mite pests of tomato, Tetranychus evansi Baker and Pritchard is one of the most important in many countries. This mite has been found in the Americas, Africa, Europe and more recently, in Asia. In Africa, this pest causes losses of up to 90% in the tomato production. T. evansi is an unfavourable prey for the most common predatory mites studied until recently. In order to reduce the losses caused by T. evansi in África, a classical biological control program was initiated with the intention of identifying exotic natural enemies of T. evansi in South America that can be potentially introduced into Africa. The searches are being conducted on Solanaceae plants in areas of South America with similar climatic conditions of those where T. evansi is found in Africa. Three predatory mites (Phytoseiidae) were found associated with T. evansi in Uruguaiana-RS, Phytoseiulus longipes Evans, Phytoseiulus fragariae Denmark and Schicha and Neoseiulus californicus (McGregor). Laboratory and field studies with P. longipes presented promising results and demonstrated that this predator is a potential candidate agent against T. evansi. The potential of the two other predatory species against T. evansi is unknown. The objective of this study was to evaluate the potential of P. fragariae and N. californicus in the biological control of T. evansi and T. urticae in Solanaceae.

As pragas urbanas constituem enormes riscos para a saúde de nossas comunidades, em uma relação sinantrópica em que os artrópodes peçonhentos assumem um papel primordial. Iniciativas de controle são efetivadas em regiões de elevada incidência, como no caso do município de Americana, estado de São Paulo, através de captura mecânica de escorpiões em cemitérios municipais, desde 2006. Durante essas atividades, verificou-se que os escorpiões evitavam ambiências com a presença de fungos filamentosos, levantando a hipótese de que existiria uma possível barreira biológica nociva aos mesmos. Nesse contexto, esse trabalho objetivou o estudo de interações entre isolados de fungos filamentosos e escorpiões coletados de um mesmo ambiente, através de cinco etapas de bioensaios. Os dados obtidos foram analisados estatisticamente, considerando-se um delineamento experimental casualizado em blocos. Foi realizado o teste F da análise da variância ao nível de 5% de significância. As médias de cada ambiência testada de cada bioensaio foram comparadas pelo teste de Tukey (α= 0,05). Os resultados indicaram dois isolados de fungos (Mucor sp. e Phialophora sp.) com maior potencial de repelência e três isolados (Paecilomyces sp. - isolado 1, Rhizopus sp. e Fusarium sp. - isolado 4), com maior mortalidade para T. serrulatus. Em sequência, foram selecionados os isolados de Paecilomyces sp. e Rhizopus sp. com indicação de maior mortalidade. Os extratos brutos desses isolados foram submetidos a partições líquido-líquido com acetato de etila e água para obtenção de frações ativas, com avaliação de maior efeito escorpionicida para a fração acetato de Paecilomyces sp. A fração acetato de Paecilomyces sp. foi submetida a uma extração em fase sólida com 19 frações resultantes que foram submetidas a cromatografia em camada delgada, com a seleção de seis frações por similaridade. Duas frações ativas C e D apresentaram maior efeito escorpionicida em bioensaio e foram analisadas em cromatografia líquida de ultra eficiência acoplada à espectrometria de massas de alta resolução, resultando em um composto ativo de massa molar de 375 Da. No banco de dados Dictionary of Natural Products (CHEMnetBASE) foram encontrados 137 metabólitos secundários compatíveis com esse composto, mas sem referência de atividade inseticida que estivesse associada ao efeito escorpionicida demonstrado nos bioensaios. A identificação molecular do isolado de Paecilomyces sp. indicou uma sequência de 569 pb para a espécie Paecilomyces formosus. / Urban pests pose enormous risks to the health of our communities, in a synanthropic relationship in which venomous arthropods play a primordial role. Control initiatives are carried out in regions of high incidence, such as in the municipality of Americana, São Paulo State, through mechanical capture of scorpions in cemeteries since 2006. During these activities, it was verified that the scorpions avoided environments with the presence of filamentous fungi, raising the hypothesis that there would be a possible biological barrier harmful to them. In this context, this work aimed to study the interactions between isolates of filamentous fungi and scorpions harvested from the same environment through five stages of bioassays. The data obtained were statistically analyzed, considering a randomized block design. The F test of the analysis of variance was performed at the 5% level of significance. The means of each environment tested from each bioassay were compared by the Tukey test (α= 0.05). The results indicated two isolates of fungi (Mucor sp. and Phialophora sp.) with higher potential for repellency and three isolates (Paecilomyces sp., Rhizopus sp. and Fusarium sp.) with a higher mortality to T. serrulatus. In sequence, the isolates of Paecilomyces sp. and Rhizopus sp. were selected with indication of higher mortality. The crude extracts of those isolates were submitted to liquid-liquid partitions with ethyl acetate and water to obtain active fractions, with evaluation of a higher scorpionicidal effect for the acetate fraction of Paecilomyces sp. The acetate fraction of Paecilomyces sp. was subjected to a solid phase extraction with 19 resulting fractions, again submitted to thin layer chromatography, with the selection of six fractions by similarity. Two active fractions (C and D) presented a higher scorpionicidal effect and were analyzed by ultra high performance liquid chromatography coupled to high resolution mass spectrometry, resulting in an active compound of 375 Da molar mass. In the Dictionary of Natural Products (CHEMnetBASE) database were found 137 secondary metabolites compatible with this compound but without reference to insecticidal activity that was associated with the scorpionicidal effect demonstrated in the bioassays. The molecular identification of Paecilomyces sp. indicated a 569 bp sequence for the species Paecilomyces formosus.

A mosca-branca Bemisia tabaci (Gennadius) é considerada uma das principais pragas agrícolas. Seu controle é realizado principalmente com a utilização de inseticidas, que entretanto não tem funcionado a contento. Uma alternativa seria a utilização de ácaros predadores da família Phytoseiidae, como agentes de controle. O ácaro predador Amblyseius swirskii Athias-Henriot tem se mostrado um eficiente agente de controle desta praga em outros países, porém este não foi até o momento constatado no Brasil. Sua introdução poderia viabilizar o controle biológico da mosca-branca no país, sendo, porém, necessária a condução de estudos prévios, para avaliar sua eficiência como agente de controle do biótipo B de B. tabaci, encontrado no Brasil. Uma população de A. swirskii coletada na República de Benin e outra comercialmente disponível na Holanda foram recentemente introduzidas no Brasil para estudos. No primeiro estudo relatado neste documento, as duas populações foram comparadas quanto à habilidade de predação e oviposição quando alimentadas com ovos de B. tabaci de diferentes idades e com outros alimentos. Melhor desempenho foi apresentado pela população da Holanda, mas para ambas as populações, maiores níveis de predação e oviposição foram observados em ovos mais novos (< 24 h de idade) de B. tabaci. No segundo estudo avaliou-se o potencial biótico desta população quando alimentada com ovos de B. tabaci ou pólen de Typha domingensis Persoon, e o efeito de ambas as populações sobre larvas de Euseius concordis (Chant), fitoseídeo comumente encontrado no Brasil. A taxa intrínseca de aumento populacional foi relativamente alta em ambos os alimentos, sendo ligeiramente mais alta em ovos de B. tabaci que em pólen (respectivamente 0,29 e 0,25 fêmea/fêmea/dia). Fêmeas adultas de ambas as populações predaram larvas da própria espécie e, em maiores níveis, de E. concordis, independentemente da presença de pólen. No terceiro estudo, avaliou-se o potencial de populações brasileiras de fitoseídeos como predadores de B. tabaci, assim como o desempenho destes em outros alimentos. Os fitoseídeos avaliados foram Amblydromalus limonicus (Garman & McGregor), Amblyseius herbicolus (Chant), Amblyseius largoensis (Muma), Amblyseius tamatavensis (Blommers) e Neoseiulus tunus (De Leon). Todos predaram ovos de B. tabaci. Contudo, melhores resultados foram observados para A. herbicolus, A. tamatavensis e N. tunus. Os resultados sugerem que estas espécies sejam promissoras como agentes de controle de B. tabaci. No quarto estudo, avaliou-se o potencial biótico de A. tamatavensis quando alimentado com ovos de B. tabaci e seu desempenho no controle desta praga em plantas jovens de pimentão (Capsicum annuum L.). A taxa intrínseca de aumento populacional foi comparável à obtida para A. swriskii alimentando-se da mesma presa. Por outro lado, a liberação deste predador resultou em reduções de 60 a 80% nas densidades da praga, sugerindo que A. tamatavensis seja promissor como agente de controle de B. tabaci. Conclui-se que exista um grande potencial de se controlar B. tabaci no Brasil com o uso de espécies de fitoseídeos, seja com uma espécie em fase de introdução, A. swirskii, seja com uma espécie já presente no país, A. tamatavensis. / The whitefly Bemisia tabaci (Gennadius) is considered a major agricultural pest. Its control is mainly done with the use of insecticides, which however have not provided satisfactorily. An alternative could be the use of predatory mites of the family Phytoseiidae as control agents. The predatory mite Amblyseius swirskii Athias-Henriot is an effective control agent of this pest in other countries, nonetheless this species has not being found in Brazil. Its introduction could enable the biological control of whitefly in the country. However, preliminary studies carried are still necessary to evaluate its effectiveness as a control agent of B. tabaci biotype B, found in Brazil. One population of A. swirskii collected in the Republic of Benin and the other commercially available in the Netherlands, have been recently introduced to Brazil for studies. On the first study reported in this paper, two populations were compared in relation to their ability to prey and oviposit when fed with B. tabaci eggs of different ages and with other food sources. The best performance was presented by the Netherlands population, but for both populations, higher predation and oviposition levels were observed on younger eggs (< 24h). In the second study, we evaluated the biotic potential of the same population when fed with B. tabaci eggs or pollen of Typha domingensis Persoon as well as the effect of both populations on the larvae of Euseius concordis (Chant), phytoseiid commonly found in Brazil. The intrinsic rate of population increase was relatively high on both food types, being slightly higher on eggs of B. tabaci than on pollen (respectively 0.29 and 0.25 female/female/day). Adults females of both populations preyed on their on larvae and also the highest levels of E. concordis, regardless of the presence of pollen. In the third study, we evaluated the potential of Brazilian populations of phytoseiids as predators of B. tabaci, as well as their performance on other food sources. The phytoseiid species evaluated were Amblydromalus limonicus (Garman & McGregor), Amblyseius herbicolus (Chant), Amblyseius largoensis (Muma), Amblyseius tamatavensis Blommers and Neoseiulus tunus (De Leon). All species preyed on eggs of B. tabaci, but best results were observed for A. herbicolus, A. tamatavensis and N. tunus. The results suggest that these species are promising as control agents of B. tabaci. In the fourth study, we evaluated the biotic potential of A. tamatavensis when fed on eggs of B. tabaci and its performance in controlling this pest in young bell pepper (Capsicum annuum L.) plants. The intrinsic rate of population increase was comparable to that of A. swirskii fed with the same prey. On the other hand, the release of this predator resulted in a reduction of 60 to 80 % in pest density, suggesting that A. tamatavensis is promising as a control agent B. tabaci. We conclude that there is a great potential to control B. tabaci in Brazil using phytoseiid species, with a species which is now being introduced, A. swirskii, or with a species which is already present in the country, A. tamatavensis.

A família Baculoviridae é um grande grupo de vírus com cerca de 700 espécies de insetos hospedeiros, com dois fenótipos: o ODV (occlusion derived virion), que faz a infecção primária do intestino médio; e o BV (budded virus), responsável pela infecção sistêmica. No Brasil, o nucleopoliedrovírus Anticarsia gemmatalis (AgMNPV) é utilizado como controle biológico da lagarta-da-soja Anticarsia gemmatalis. O genoma do AgMNPV-2D contém 152 ORFs, 26 das quais codificam proteínas estruturais. Entre elas, a glicoproteína GP64 é fundamental para infecção secundária. Este estudo visa identificar proteínas estruturais do AgMNPV-2D por duas abordagens de espectrometria de massas. Também comparar a variabilidade da gp64 de isolados geográficos por sequenciamento por Sanger e de alta cobertura. Assim, identificamos as substituições de gp64 e vimos que ela não suporta a separação geográfica dos isolados. Também identificamos 44 e 33 proteínas em ODV e BV, respectivamente. Seis novas proteínas foram identificadas no ODV e sete delas no BV. Além disso, 11 proteínas celulares foram identificadas no AgMNPV-2D, possivelmente necessárias para infecção. Este achado contribui para o entendimento da morfogênese do AgMNPV e fatores associados à multiplicação viral. / Baculoviridae are arthropod-specific viruses with more than 700 host insects, which produce two phenotypes: the budded virus (BV) and, the occlusion-derived virus (ODV) for intra and across host spread, respectively. Brazil uses the Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) as a biological control agent of the velvet bean caterpillar (A. gemmatalis). The genome of the AgMNPV-2D carries 152 ORFs, 26 of which code for structural proteins. Herein, the structural proteins of AgMNPV-2D were analyzed by two mass spectrometry techniques. The additional objective was to compare the gene gp64. of different geographical populations by Sanger and next generation sequencing. This analysis allowed us to observe the substitutions of gp64 and refuted the notion of a geographical isolation of the samples. We also observed a total of 44 proteins of the ODV and 33 of the BV. Six new proteins were found in the ODV and seven in the BV. Furthermore, 11 cellular proteins were also identified, which are possibly assorted during viral morphogenesis. These findings may provide novel insights into AgMNPV biology and its host interaction, leading us to a better understanding about morphogenesis and also the associated factors of the viral multiplication.

Cucurbits (i.e. squash, melons, pumpkins, gourds) are high value crops of global importance. Insect pests in these systems are often controlled by chemical insecticides, which are not always effective and can be damaging to the environment. Many integrated pest management (IPM) techniques have been developed for the control of pests in these systems, with a goal of improving system stability and reducing chemical inputs. The overarching goal of my research was to investigate the impact of select IPM techniques on arthropod populations and yield in organic and conventional cucurbit systems. This dissertation can be divided into three major projects which were conducted between 2013 and 2017. First, an investigation was conducted to understand the impact of two commonly used IPM practices (tillage regime and the use of row covers) on pest insect populations, beneficial arthropod populations, and plant yield. By developing studies in both organic and conventionally managed squash and melon production, four independent studies were conducted and analyzed to provide a broad understanding of these IPM strategies. In all systems, plant yields and pests were greatest in the plasticulture systems, but reduced tillage had a positive impact on the natural enemy arthropods within these crops. Row cover use resulted in larger plants and increased yields, but had an inconsistent influence on arthropods in the systems studied. From these initial studies, an additional investigation was developed to better understand the impacts of cultivation on the specialist pollinator Peponapis pruinosa [Hymenoptera: Apidae]. Nesting site selection was examined in two independent experiments. By conducting choice studies to allow P. pruinosa to select preferred nesting sites, we determined that P. pruinosa prefer to build nests in loose soils and show reduced nest making in compact soils. This poses interesting management challenges since less-compact soils are within high tillage zones. This research supports the need for the development of cultivation management plans that consider of pollinator habitat and reproduction needs. A multi-year, multi-farm study was developed for the comparison of parasitism in cucumber beetles (Acalymma vittatum and Diabrotica undecimpunctata) in organic and conventional growing systems. Parasitoids were reared from beetles collected from working organic and conventional cucurbit farms in central Kentucky. Our results show that there is some seasonal variation in parasitism, but that there is no significant difference between organic and conventional production. We conclude that IPM techniques can be effective in contributing to the control cucurbit pests in agroecosystems and the improvement of crop yields. These studies show that natural enemies and pollinators react differently to IPM practices, which should be considered when developing IPM plans in cucurbit production. By researching these management techniques we are able to develop production systems that have increased stability.

Emerald ash borer (EAB), Agrilus planipennis (Coleoptera: Buprestidae), is an aggressive invader from Asia that has killed millions of trees in North America. Recently EAB has been documented developing in a novel host, white fringetree, Chionanthus virginicus. I evaluated larval performance in two common ash species and white fringetree by infesting excised bolts with emerald ash borer eggs. In addition I evaluated several plant characteristics to determine which most influence larval development. I also conducted choice and no choice assays using the classical biological control agent, Tetrastichus planipennisi (Hymenoptera: Eulophidae), to assess its ability to locate larval EAB in the different host plants. I found significantly lower survival rates of EAB larvae in white fringetree compared to white ash, F. americana. Larval phloem consumption and larval growth were lower in fringetree than in both ash tested. In choice and no choice assays T. planipennisi failed to parasitize larvae in fringetree. Failure of T. planipennisi to parasitize larvae within fringetree has implications for the efficacy of this classical biological control agent. Coupled with the use of white fringetree as a reservoir host, the enemy free space provided to EAB through use of this alternate host may have repercussions for EAB invasion dynamics.

Thesis (M.SC. (Aquaculture)) --University of Limpopo, 2011 / The present MSc dissertation emanates from seasonal surveys conducted by the fish parasitological group of the Department of Biodiversity and Aquaculture Research Unit of the University of Limpopo, Turfloop Campus. The first part of the present study was aimed at investigating the metazoan parasites of three cyprinids occurring in the Nwanedi-Luphephe Dams. The main purpose of it was to determine temporal changes in the intensity of infestation in terms of prevalence, mean intensity and abundance of parasite species parasitizing the cyprinids studied over a two year period. Ecological parameters including species host-specificity, seasonality, and gender preference and host size versus species intensity are discussed for each parasite. Altogether 152 specimens were examined for parasites and a total of 2 432 metazoan parasites of ten species were recorded. At the sampling site, all three hosts co-occurred, however, a substantial proportion of Barbus radiatus was collected from the perennial stream feeding one of the twindams. Fish were sampled by means of gill nets and electrofishing or seine netting in accordance with the habitat conditions. Hosts were killed and organs investigated for metazoan parasites. After collection of parasites, standard methods for processing individual parasites were followed. The results obtained revealed the following groups of parasites; monogeneans (ectoparasites) included Dactylogyrus spinicirrus, D. afrolongicornis afrolongicornis, D. afrolongicornis alberti, Afrodiplozoon polycotyleus, Gyrodactylus sp., and Dogielius sp. (all recorded from the gills); Crustacea, Dolops ranarum was found from the mouth cavity, gills and skin of Labeobarbus marequensis. Of these, only two specialists, both monogeneans, were found on Barbus trimaculatus namely, D. afrolongicornis afrolongicornis and D. afrolongicornis alberti. Based on morphology of the haptoral hard parts, these two species were almost similar to each other than to D. spinicirrus. The appreciable difference between D. afrolongicornis afrolongicornis and D. afrolongicornis alberti was mainly in the shape of the marginal bar. Both D. spinicirrus and A. polycotyleus were widely distributed and recorded on the gills of all hosts during all seasons. Both species were recorded for the first time on B. radiatus. Also, D. spinicirrus was recorded for the first time on the gills of B. trimaculatus. Based on comparison with the original material, the species could be identified to species level. These analyses provided sufficient evidence for restoration of Afrodiplozoon polycotyleus as a valid taxon. The existence of two species, Gyrodactylus sp. and Dogielius sp. were recorded for the first time on B. radiatus in South Africa, and this possibly represents new species. The endoparasites included the following groups: digeneans- Diplostomulum metacercariae from the eyes of Lb. marequensis, Ornithodiplostomum sp. and black spot (grubs) were recorded from B. trimaculatus. The latter was also recorded in the muscle of B. radiatus. Unidentified digenean cysts were recovered from the gills and in the body cavity of both Lb. marequensis and B. trimaculatus; nematodes were represented by Contracaecum larvae in the body cavity of both Lb. marequensis and B. trimaculatus; cestodes were represented by gryporynchid larvae from the intestine of B. radiatus. The general high prevalence and intensities of ectoparasites recorded is an indication that the Nwanedi-Luphephe Dams has a biotic mechanism which might have enabled it to sustain the growth rate of ectoparasite intra-population. There was no correlation between either fish length or condition factor and the number of parasites. The study indicated that the abundance of monogeneans is partly influenced by season and that of endoparasites was principally governed by the presence of intermediate hosts and definitive hosts. The second part of this dissertation dealt with the health status of Lb. marequensis. Fish health was assessed using condition-related indices including condition factor and a modified Health Assessment Index (HAI) and the associated Parasite Index (PI). The HAI was performed to determine and examine any macroscopic abnormalities regarding external features and internal organs. The purpose of combining the two indices was to use the infestation of the metazoan parasites found on and/or in Lb. marequensis to determine whether or not the environment they live in was healthy. Both indices together with the condition factor provided relatively simple and rapid indications of how well fish were coping in their environment. The HAI score varied amongst the four sampling seasons. The highest individual mean value was 63 in winter, followed by a score of 50 in autumn, while the lowest were 42 and 33 in summer and spring respectively. To authenticate the HAI and PI data, certain water quality variables were measured and are discussed in detail in this dissertation. The Nwanedi-Luphephe Dams are generally believed to have good water quality. This was supported in this study; conditions assessed in fish using the aforementioned indices did not differ greatly between seasons, nor did the conditions deviate appreciably from normality. The HAI values were low overall which signifies a healthy fish profile for the system. The present investigation showed the existence of differences in the occurrence of individual parasite to be linked to water temperature changes. Thus, seasonal changes do influence parasite developmental stages to a certain degree. Tested heavy and trace metals were within the permissible limits as provided by the Department of Water Affairs and Tourism (DWAF, 1996).

Thesis (M.Agric. (Horiticulture)) --Unversity of Limpopo, 2013 / The ground leaching technology (GLT) system, using crude extracts of wild cucumber (Cucumis myriocarpus) and wild watermelon (Cucumis africanus) fruits, had been widely researched and developed in management of the root-knot (Meloidogyne species) nematodes in tomato (Solanum lycopersicon) production. In the GLT system, experiments were harvested at 56 days after inoculation with nematodes, which was approximately three generations of Meloidogyne species. Also, studies in GLT systems demonstrated that effective micro-organisms (EM) were not essential in the release of chemicals from crude extracts for nematode suppression, with suggestions that the system exclusively relied upon irrigation or rainwater for leaching out chemicals. However, the system had hardly been tested on other nematode species with longer life cycles and crops. The objective of this study was to investigate the influence of crude extracts of C. myriocarpus (cucurbitacin A-containing phytonematicide) and C. africanus (cucurbitacin B-containing phytonematicide) with and without EM on suppression of population densities of the citrus nematode (Tylenchulus semipenetrans) on rough lemon (Citrus jambhiri) over three generations of the nematode. Two studies, one on C. myriocarpus and the other on C. africanus, with and without EM, were conducted separately using the GLT system under greenhouse conditions with three generations of T. semipenetrans as the standard of application interval of the materials. Citrus seedlings were transplanted in 7-L plastic pots contain 6.5-L pasteurised river sand and Hygromix (3:1 v/v) and inoculated with approximately 25 000 second-stage juveniles (J2s) in 2 × 2 × 2 factorial experiment, where treatments were arranged in a randomised complete block design (RCBD), with six replications. At 150 days after treatment, nematode and plant variables were collected and subjected to factorial analysis of variance. Under C. myriocarpus (Cm), EM × Cm interaction was not significant for nematodes (juveniles + eggs) in roots and juveniles in soil, while under C. africanus (Ca), EM × Ca interaction was highly significant for nematodes, but not for juveniles. Crude extracts of C. myriocarpus and C. africanus fruits contributed 21-36% and 38-59% to total treatment variation in nematodes, respectively. Relative to untreated control, crude extracts of C. myriocarpus fruit reduced nematodes by 22% in roots, but increased juveniles in soil by 93%. Similarly, C. africanus fruit reduced nematodes in roots by 80%, but increased juveniles in soil by 178%. The increase of juveniles in the soil was explained on the basis of opposing forces on nematode population densities under crude extracts of Cucumis and untreated control, along with the inherent nature of cyclic population growth in plant-parasitic nematodes. In plant variables, certain significant (P ≤ 0.05) interactions consistently occurred under both Cucumis species. However, effects of the interactions were not consistent under the two Cucumis species. In most of the variables, the non-significant effects of EM × Cm interactions supported the view that the GLT systems were independent of microbial activities, while significant (P ≤ 0.05) EM × Ca interactions suggested that the systems under C. africanus fruit could be viewed as being dependent upon microbial degradation activities. Growth of rough lemon rootstock was, to a certain extent, suppressed by application of crude extracts from Cucumis fruits, suggesting that the material were phytotoxic to this citrus rootstock. Under low nematode population densities, T. semipenetrans infection supported the view that nematode numbers below the damage threshold levels have stimulatory effects on growth of plants as observed in plant height under conditions of this study. In conclusion, the approximately three nematode-generation-application interval of 150 days for crude extracts of fruits in Cucumis species was rather too long for the efficacies of the materials on suppression of the population densities of T. semipenetrans in rough lemon seedlings. Consequently, shorter application intervals, as demonstrated for Meloidogyne species would be appropriate, although caution has to be taken to ensure that phytotoxicity to the rootstock was avoided.