Os parabenos são conservantes utilizados em alimentos, fármacos, cosméticos e produtos de cuidado pessoal. Pertencem à família de ésteres do ácido p-hidróxibenzoico, distinguindo-se entre si pelo comprimento e ramificação da cadeia lateral alquílica. Nesse contexto, o objetivo principal dessa tese foi avaliar os efeitos dos dois parabenos mais frequentemente utilizados (metilparabeno e propilparabeno) sobre diferentes espécies de ambientes aquáticos. Para isso, inicialmente, foram realizados testes de toxicidade de curta duração com cinco espécies de organismos de diferentes grupos taxonômicos e funcionais, sendo quatro delas de regiões tropicais (Ceriodaphnia silvestrii, Chironomus xanthus, Macrothrix flabelligera e Hydra viridissima) e uma pertencente às regiões temperadas (Hydra attenuata). Os resultados obtidos nesses testes foram comparados com os resultados de literatura aberta, mostraram que Ceriodaphnia silvestrii (MeP CE50=7,56 mgL e PrP, CE50=2,90 mgL) e Macrothrix flabelligera apresentaram-se mais sensíveis em comparação aos organismos padrão de clima temperado. Num segundo momento, foram realizados testes de toxicidade com sete espécies de fungos hifomicetos aquáticos (Articulospora tetracladia Ingold, Flagellospora curta Webster, Heliscus lugdunensis Sacc. & Thérry, Lemonniera aquatica Wildeman, Lemonniera pseudofloscula Dyko et al., Tetracladium apienses R.C. Sinclair & Eicker, Tetracladium marchalianum Wild.) expostas ao conservante propilparabeno, por possuir maior ação antifúngica. Lemonniera aquatica apresentou maior sensibilidade ao propilparabeno, sendo o mais sensível de todos os fungos testados, bem como dos demais organismos aquáticos reportados na literatura. Além de confirmarem que os parabenos representam risco ecológico potencial para os ambientes aquáticos, os resultados obtidos permitiram concluir que há diferenças de sensibilidade entre as espécies tropicais e temperadas e, por isso, as espécies nativas são mais indicadas para se avaliar os efeitos tóxicos dos parabenos nos ambientes. Dada a presença e persistência dos compostos estudados por entrada contínua no ambiente, a magnitude das concentrações determinadas (ng L-1 e μg L-1), a carência de informações relativas à toxicidade e ao risco que representam para os ecossistemas tropicais, incluindo os do Brasil, sugere-se a implantação pelas agências reguladoras de medidas mais restritivas para o uso desses conservantes, visando uma melhor proteção da biota aquática. / Parabens are preservatives used in foods, pharmaceuticals, cosmetics and personal care products. They belong to the family of esters of p-hydroxybenzoic acid, distinguishing each other by the length and branching of the alkyl side chain. The main objective of this thesis was to evaluate the effects of the two most commonly used parabens, methylparaben and propylparaben, on aquatic species. For this purpose, short-term toxicity tests were initially carried out on five species of organisms from different taxonomic and functional groups: four of them from tropical regions, Ceriodaphnia silvestrii, Macrothrix flabelligera, Chironomus xanthus and Hydra viridissima, and one belonging to temperate regions, Hydra attenuata. The results obtained in these tests were compared with the results of the open literature, showing that Ceriodaphnia silvestrii (MeP, EC50 = 7.56 mg L-1 and PrP, EC50 = 2.90 mg L-1) and Macrothrix flabelligera (MeP, EC50 = 8.04 mg L-1 and PrP, EC50 = 3.85 mg L-1) were more sensitive compared to the standard organisms of temperate climate. Secondly, toxicity tests were performed with seven species of aquatic hyphomycetes fungi and only with the preservative propylparaben, because they have a higher antifungal action: Articulospora tetracladia Ingold, Flagellospora curta Webster, Heliscus lugdunensis Sacc. & Thérry, Lemonniera aquatica Wildeman, Lemonniera pseudofloscula Dyko et al., Tetracladium apienses R.C. Sinclair & Eicker, Tetracladium marchalianum Wild. Lemonniera aquatica showed greater sensitivity to propylparaben (EC50 = 1.63 mg L-1), being more sensitive than all fungi, as well as other aquatic organisms. Thus, the results obtained in the present thesis indicate that there is a difference in sensitivity between tropical and temperate species when exposed to parabens, with tropical native species being more sensitive to the effects of these compounds. Given the presence and persistence of the compounds studied by continuous entry into the environment, the magnitude of the concentrations determined (ng L-1 and μg L-1), the lack of toxicity and risk information for tropical ecosystems, including Brazil, it is suggested that regulatory agencies implement more restrictive measures for the use of these preservatives, aiming at a better protection of the aquatic biota.

Com o aumento da população mundial, torna-se necessário a busca de tecnologias para o incremento da produção de alimentos. O cultivo da soja (Glycine max (L.) Merrill) destaca-se entre as atividades econômicas mundiais que apresentam crescimentos expressivos nas últimas décadas e apesar da crescente expansão territorial e produção agrícola, tem a produtividade influenciada por fatores externos e internos durante o cultivo, sendo o principal deles, a incidência de doenças. Atualmente, a doença mais preocupante é a ferrugem da soja, causada pelo fungo Phakopsora pachyrhizi Sydow & Sydow. Para o controle desta doença devastadora, recomenda-se a aplicação concomitante de fungicidas triazóis e estrobilurinas, que, conforme alguns dados da literatura, além de atuarem de forma protetora e curativa, apresentam efeitos na produtividade. O objetivo do trabalho foi esclarecer o efeito fisiológico do triazol ciproconazol e da estrobilurina azoxistrobina em plantas de soja sem incidência de ferrugem. O trabalho foi realizado em casa de vegetação no Departamento de Ciências Biológicas da ESALQ/ USP, em Piracicaba, SP no período entre dezembro de 2008 a maio de 2009 com plantas de soja cultivar Pintado. As condições hídricas e do solo foram mantidas conforme as recomendações para a cultura. Os tratamentos foram constituídos pelos fungicidas Ciproconazol (triazol), Azoxistrobina (estrobilurina) e Óleo mineral (Nimbus) e as aplicações realizadas nos estádios R1, R4 (duas aplicações) e R1, R4 R5,4 (três aplicações). Foram analisados aspectos de produção (Número, massa fresca, seca e média das vagens, massa seca de grãos e peso de 100 grãos) e aspectos anatômicos (espessura do limbo foliar, espessura e largura da nervura central, espessura do xilema e do floema), sendo que nestas análises, foram utilizados apenas os tratamentos em que foram realizados três aplicações do fungicida. O delineamento experimental foi em blocos inteiramente ao acaso, com 9 tratamentos e 5 blocos. Os resultados apontam redução no número de vagens por planta, massa fresca e seca das vagens, número de grãos e massa seca de grãos tratados com a mistura entre o triazol e a estrobilurina. Sob o aspecto anatômico, houve incremento na espessura do limbo foliar, espessura e largura da nervura central e a espessura do sistema vascular (xilema e floema). Com base nos dados obtidos no trabalho, conclui-se que, nas condições em que foi realizado, a aplicação do triazol e da estrobilurina em plantas de soja restringe o potencial de produção de grãos no cultivar Pintado. / With increasing world population, it is necessary to search for technologies to increase food production. The cultivation of soybean (Glycine max (L.) Merrill) stands out among the economic activities that present significant growth worldwide in recent decades, and despite the increasing territorial expansion and agricultural production, productivity is influenced by external and internal factors during cultivation , the main one being, the incidence of diseases. Currently, the disease more worrying soybean is rust caused by Phakopsora pachyrhizi Sydow & Sydow. To control this devastating disease, we recommend the application of triazole and strobilurin fungicides, which, according to some literature data, act so protective and curative, and have effects on productivity. The objective of this study was to clarify the physiological effect of the triazole cyproconazole and strobilurin azoxystrobin in soybean without rust incidence. The study was conducted in a greenhouse at the Department of Biological Sciences ESALQ / USP, Piracicaba, SP, Brazil in the period between December 2008 and May 2009 with soybean cultivar Pintado. The soil and water conditions were maintained as recommended for the crop. The treatments consisted of fungicides cyproconazole (triazole), azoxystrobin (strobilurin) and mineral oil (Nimbus) under applications at the stages R1, R4 (two applications) and R1, R4, R5, 4 (three applications). We analyzed aspects of production (number, fresh, dry and average pod dry grain and 100-grain weight) and anatomical aspects (leaf thickness, width and thickness of the midrib, thickness of xylem and phloem), and in these analyzis, we used only the treatments that were performed three applications of fungicide. The experimental design was a randomized block design with 9 treatments and 5 blocks. The results showed a reduction in the number of pods per plant, fresh and dry weight of pods, number of grains and dry grain treated with the mixture of triazole and strobilurin. Under the anatomical aspect, there was an increase in leaf thickness, width and thickness of the midrib and the thickness of the vascular system (xylem and phloem). By the data obtained in the study, it was concluded that, under the conditions in which it was performed, the application of triazole and strobilurin in soybean plants restricts the potential for grain production in the cultivar Pintado.

Atualmente, a produtividade da cultura da batata (Solanum tuberosum L.) pode ser reduzida devido à ocorrência de doenças em todo o território nacional, destacando-se a pinta preta, causada por Alternaria spp. Historicamente se acreditava que A. solani (AS) era a principal causadora mas, atualmente, descobriram outras espécies associadas, sendo predominante hoje, em território nacional a espécie A. grandis (AG). O objetivo deste trabalho foi avaliar a sensibilidade in vitro de três isolados de A. grandis e um isolado de A. solani frente a onze fungicidas amplamente utilizados no manejo desta doença em campo. Foi avaliado o efeito dos fungicidas sobre o crescimento micelial dos isolados, utilizando-se do método da incorporação do fungicida no meio de cultura fundente. As diluições dos fungicidas foram realizadas em água destilada e esterilizada, de acordo com a metodologia descrita por Camargo (2013) e Ishizuka (2016). Para os fungicidadas com mistura de ingrediente ativo, considerou-se a soma das concentrações no cálculo. Inicialmente, as concentrações do meio de cultura, foram 100, 10, 1, 0,1, 0,01 e 0,001 mg L-1. Após, as doses foram ajustadas conforme a CI50 de cada fungicida. Quantificou-se também a inibição sobre a germinação dos conídios nas contrações discriminatórias de 0; 0,1; 1; 10 e 100 mg.L-1 .24 horas após o preparo do meio as placas foram observadas em microscópio óptico, determinando-se a germinação dos conídios em 300 unidades observadas por placa de Petri. Todos os isolados testados foram altamente sensíveis aos ingredientes ativos fluazinam, pirimetanil, procimidona e piraclostrobina. Não houve diferenças de comportamento de sensibilidade entre as espécies de A. solani e A grandis que possam caracterizar uma perda de sensibilidade por conta da predominância da espécie de A. grandis associada à pinta preta da batata no Brasil. Encontraram-se evidências de insensibilidade dos isolados de A. grandis e A. solani aos ingredientes ativos Clorotalonil e Boscalida. / Currently, the productivity of potato crop (Solanum tuberosum L.) may be reduced due to the occurrence of disease throughout the country, especially due to early blight, caused by Alternaria spp. Historically it was believed that A. solani (AS) was the main cause, most currently was founded others associated species, being predominant today the occurrence of the disease associated with the species A. grandis (AG). The objective of this study was to evaluate the in vitro susceptibility of three isolates of A. grandis and one isolate of A. solani for eleven fungicides widely used in the management of this disease in the field, was evaluated the effect of fungicides on mycelial growth using the fungicidal method that incorporate it in the medium culture. Dilutions of fungicides were performed in sterile distilled water according to the methodology described by Camargo (2013) and Ishizuka (2016). For the fungicidates with active ingredient mixture, was considered the sum of the both concentrations in the calculation.The concentrations of the culture medium were 100, 10, 1, 0.1, 0.01 and 0.001 mg L-1. The doses were adjusted according to the CI50 of each fungicide, was quantified also the inhibition of spore germination, and the fungicides were incorporated into the agar medium - water in discriminatory contractions of 0; 0.1; 1; 10 and 100 mg.L-1 . Then, 24 hours after preparation of the medium the plates were observed under an optical microscope, determining the spore germination observed at 300 units per plate. All tested isolates were highly sensitive to the active ingredients fluazinam, pyrimethanil, procymidone and pyraclostrobin. There was no sensitivity behavioral differences between species of A. solani and A. grandis which may characterize a loss of sensitivity due to the predominance of species of A. grandis associated with early blight in Brazil, was found evidences of insensitivity of isolates of A. grandis and A. solani to the active ingredients Chlorothalonil and Boscalida.

Atualmente, a produtividade do feijoeiro comum (Phaseolus vulgaris L.) pode ser reduzida devido à ocorrência de doenças em todo o território nacional, destacando-se a murcha de fusário, causada por Fusarium oxysporum f. sp. phaseoli (Fop). No campo, o patógeno é disseminado a longas distâncias através das sementes infectadas e/ou contaminadas e a sua sobrevivência ocorre, principalmente, no solo. Os objetivos deste trabalho foram: avaliar a inibição do crescimento micelial de Fop por Trichoderma spp.; classificar a sensibilidade in vitro de Fop e Trichoderma spp., separadamente, a fungicidas e verificar a compatibilidade entre fungicidas químicos e biológicos para controle de Fop, presente nas sementes e no solo. Para avaliar a inibição do crescimento micelial de Fop, foram utilizados três isolados do patógeno, os quais foram confrontados, in vitro, com três isolados de Trichoderma spp. em testes de cultura pareada e produção de metabólitos voláteis a 20-22°C. Os experimentos foram conduzidos em delineamento inteiramente casualizado, com cinco repetições para cada isolado de Trichoderma. Para a classificação da sensibilidade in vitro de Fop e Trichoderma a fungicidas, foram avaliados os mesmos isolados anteriormente utilizados. Foram comparados dez fungicidas, em doses entre 0 a 100 mg L-1 que foram ajustadas de acordo com a CI50 de cada fungicida. Com base na percentagem de inibição do crescimento micelial, foram estimados os valores da concentração inibitória de 50% (CI50) e 100% (CI100) e selecionaram-se os fungicidas compatíveis com Trichoderma spp. A compatibilidade entre tratamentos químico e biológico foi avaliada através da inoculação artificial de sementes de feijão com um isolado de Fop (IAC 11.299-1) e infestação do mesmo no solo. As sementes foram tratadas com os fungicidas fludioxonil, flutriafol e tiofanato metílico, e com os três produtos biológicos, separadamente e em misturas. Avaliou-se o efeito dos tratamentos por meio dos testes de sanidade, germinação, comprimento de plântulas, massa da matéria seca em laboratório e índice de velocidade de emergência e porcentagem de emergência em estufa não climatizada. O efeito protetor dos tratamentos foi verificado através do teste de transmissão do patógeno solo-planta. Todos os isolados de Trichoderma apresentaram antagonismo in vitro contra Fop. No teste de cultura pareada foi observada uma redução de 15 a 20% no crescimento micelial do patógeno. No teste de produção de metabólitos voláteis, o isolado T12-1086G05 foi responsável pela maior inibição do crescimento micelial de Fop (10 a 48%). Os testes de sensibilidade in vitro mostraram que tiofanato metílico, flutriafol e fludioxonil foram compatíveis com Trichoderma (CI50 > 2 mg L-1). Com exceção do flutriafol e do GF 422 isolados e em mistura, todos os tratamentos foram eficientes na erradicação de Fop nas sementes, sem afetar a sua qualidade fisiológica. No teste de transmissão, verificou-se que a incidência de Fop foi de 5 a 40% no hipocótilo e de 5 a 30% nas raízes de feijoeiro provenientes de sementes tratadas com os produtos. / Currently, the common bean (Phaseolus vulgaris L.) productivity can be reduced due to the occurrence of diseases in all over the country, especially Fusarium wilt, caused by Fusarium oxysporum f. sp. phaseoli (Fop). In the field, the pathogen is spread to long distances through infected and/or contaminated seeds and its survival occurs, mainly, in the soil. The objectives of this work were: to evaluate the micelial growth inhibition of Fop promoted by Trichoderma spp.; to classificate in vitro sensitivity of Fop and Trichoderma spp., separately, to fungicides and to verify the compatibility between chemical and biological fungicides to control Fop, applied on the seeds and on the soil. To evaluate the micelial growth inhibition of Fop, it was used three Fop isolates, which were in vitro confronted with three isolates of Trichoderma spp., by paired culture and antibiosis assays at 20-22°C. The experiments were conducted entirely casualized design, with five replications for each Trichoderma isolate. For the in vitro sensitivity classification, it was evaluated the same isolates of Fop and Trichoderma previously used. It was compared ten fungicides and the concentrations of 0 to 100 mg L-1, which were adjusted according to the IC50 of each fungicide. Based on the percentage of micelial growth inhibition, it was estimated the values of inhibitory concentration of 50% (IC50) and 100% ((IC100) and it was selected the compatible fungicides with Trichoderma spp. The compatibility between chemical and biological treatments were evaluated through artificial inoculation of common bean seeds with the Fop isolate IAC 11.299, following the infestation of the pathogen in the soil. Seeds were treated with fludioxonyl, flutriafol and tiofanate methyl, and with three biological products, separately and mixed. It was evaluated the treatment effects by the following assays: sanity, germination, seedling lenght, seedling dry matter in laboratory conditions and emergence speed rate and percentage of emergence in greenhouse conditions. The protective effect of the treatments was verified through the pathogen transmission experiment from soil to plant. All Trichoderma isolates showed in vitro antagonism against Fop. In the paired culture assay it was observed 15 to 20% reduction in the pathogen micelial growth. In the antibiosis assay, the isolate T12-1086G05 was responsible for the maximum micelial inhibition growth of Fop (10 to 48%). in vitro sensitivity experiments showed that thiofanate methyl, flutriafol and fludioxonyl were compatible with Trichoderma (IC50 > 2 mg L-1). Except the treatments with fluatrifol and GF 422 alone and in mixture, all the products were efficient in eradicating Fop in the seeds, without affect its physiological quality. In the transmission experiment, it was verified that the Fop incidence was 5 to 40% in the hypoticol and 5 to 30% in the common bean roots from seed treated with the products.

O Brasil é o maior produtor e exportador de suco de laranja, sendo esta uma das mais importantes atividades econômicas para o país. Os frutos são afetados pela mancha preta dos citros, causada por Guignardia citricarpa, que deprecia comercialmente os frutos, provoca queda prematura e eleva o custo de produção. Medidas alternativas ao controle químico clássico vêm sendo estudadas e, neste contexto, insere-se a indução de resistência. O presente trabalho teve como objetivo avaliar os efeitos in vitro da quitosana e radiação UV-C sobre o crescimento micelial, germinação e formação de apressórios por G. citricarpa e a ação destes agentes abióticos no controle da doença em laranjas pós-colheita, sob armazenamento ambiente e refrigerado, estudando-se também mecanismos de resistência ativados no tecido vegetal em resposta ao tratamento de melhor eficiência. Para tanto, foram utilizadas as concentrações de 0; 0,5; 1,0; 1,5; 2,0 e 3,0% de quitosana e as doses de 0,52; 1,04; 3,13; 10,44 e 15,66 kJ.m-2 da radiação UV-C. A quitosana inibiu o crescimento micelial do fungo e estimulou a germinação e formação de apressórios, os quais se mostraram morfologicamente alterados. A UV-C não inibiu o crescimento micelial, porém a maior dose ocasionou o menor crescimento. Para os experimentos in vivo, laranjas foram coletadas, lavadas, sanitizadas com hipoclorito e posteriormente tratadas. As concentrações de 0,5, 1,0 e 2,0% de quitosana e a dose de 7 kJ m-2 da UV-C apresentaram melhor resultado em laranjas ?Valência? na redução dos sintomas. Análise da cor da casca dos frutos irradiados revelou que houve leve escurecimento. Os fungicidas tiabendazol e imazalil não controlaram a doença em laranjas ?Pêra Rio?, porém, obteve-se menos lesões nos frutos tratados com os fungicidas em combinação com quitosana, tanto em temperatura ambiente quanto em refrigeração. Análises da cor da casca indicaram amarelecimento e não houve alterações significativas nos teores de sólidos solúveis, acidez titulável, pH, vitamina C e ratio. Nos ensaios com quitosana, tiabendazol e UV-C, a quitosana apresentou melhor controle da doença, aplicada isoladamente ou em conjunto com o fungicida e UV-C, em temperatura ambiente ou refrigeração. A quitosana e a proteína harpina apresentaram controle semelhante e, em comparação com o ácido cítrico, a quitosana ocasionou melhor controle em laranjas ?Valência?. Para análises bioquímicas, amostras de flavedo foram homogeneizadas em de tampão acetato, com posterior centrifugação, coletando-se o sobrenadante. Para as reações enzimáticas, foram utilizados os reagentes CM-chitin-RBV, CMCurdlan- RBB, guaiacol, catecol e L-fenilalanina para quitinase, glucanase, peroxidase, polifenoloxidase e fenilalanina amônia-liase, respectivamente. Para a determinação de fenóis, amostras do flavedo foram homogeneizadas em metanol acidificado e a dosagem feita com o reagente Folin-Ciocalteau. A quitosana induziu o aumento da atividade das enzimas nas primeiras 24 h após o tratamento, sendo neste tempo detectada a maior atividade. Não houve atividade de fenilalanina amônia-liase, bem como acúmulo de fenóis. Finalmente, fica evidenciado que quitosana e a UV-C apresentaram efeito in vitro sobre G. citricarpa, porém somente a quitosana exibiu potencial no controle da mancha preta em laranja pós colheita. / Brazil is the biggest producer and exporter of orange juice, and this is one of the most important economical activities for the country. The fruits can be affected by the citrus black spot, disease caused by the fungus Guignardia citricarpa, which depreciates then commercially, causes premature fall and increases the production cost. Alternative measures to the chemical control are being studied and, in this context, resistance induction can be considered. The present work had as objective evaluate the in vitro effects of chitosan and UV-C radiation on mycelial growth, germination and apressorium formation by G. citricarpa and the action of the abiotic agents on controlling the disease on postharvest oranges, under room temperature and refrigeration storage, also studying the mechanisms of resistance in the plant tissue in response to the better treatment. The chitosan concentrations were 0, 0.5, 1.0, 1.5; 2.0 and 3.0% and the UVC doses were 0.52, 1.04, 3.13, 10.44 and 15.66 kJ.m-2. Chitosan inhibited mycelial growth and stimulated the germination and the apressorium formation that were morphologically abnormal. UV-C did not inhibited mycelial growth, but reduced it at the highest dose used. For the in vivo experiments, oranges were collected, sanitized with hypochlorite and treated. Chitosan concentrations of 0.5, 1.0 and 2.0% and the UV-C dose of 7 kJ m-2 exhibited better results in ?Valência ? oranges. Analyses of peel color of irradiated fruits revealed a light browning. The fungicides thiabendazole and imazalil did not control the disease in ?Pêra Rio ? oranges, but fewer lesions appeared on fruits treated with the fungicides in association with chitosan, under room temperature and refrigeration. Color analysis of peel indicated yellowing and no significant differences among soluble solids, titratable acidity, pH vitamin C and ratio. In the chitosan, thiabendazole and UV-C assays, there was a better control of lesion appearing by treatment with chitosan, applied alone or in association with fungicide and UV-C, at room temperature or refrigeration. Chitosan and the harpin protein were similar on the controlling of the disease and, in comparison to the citric acid, chitosan presented better control on ?Valência? oranges. For biochemical analysis, flavedo samples were homogenized in acetate buffer, centrifuged, and the supernatant collected. The reagents used were CM-chitin-RBV, CM-Curdlan-RBB, guaiacol, cathecol and L-phenylalanine for chitinase, glucanase, peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase, respectively. For phenol determination, flavedo was homogenized in acidified methanol and the evaluation was made with Folin-Ciocalteau. Chitosan increased enzyme activities in the first 24 h after treatment, with the highest activity in that time. Activity of phenylalanine ammonia-lyase was not detected, well as absent of phenolic compounds accumulation. Chitosan and UV-C exhibited in vitro effect on G. citricarpa, however, only chitosan showed potential on the control of black spot in postharvest oranges.

Foram conduzidos quatro experimentos com a cultivar 'Carioca' do feijoeiro (Phaseolus vulgaris), objetivando a possibilidade de implementação de um sistema de manejo integrado da ferrugem e mancha angular do feijoeiro após a intervenção com os fungicidas oxycarboxin (Hokko Plantvax 750 - 700 gramas/ha) e trifenil hidróxido de estanho (Mertin â - 660 ml/ha), respectivamente, aplicados em diferentes épocas. Foi realizada a quantificação de danos nesses patossistemas, verificando por meio de regressões lineares e não lineares as possíveis relações existentes entre as variáveis integrais AUDPC (área sob a curva de progresso de doença)¸ HAD (duração da área foliar sadia) e HAA (absorção da área foliar sadia) e suas correspondentes HLAI (índice de área foliar sadio) e HRI (absorção da área foliar por unidade de tempo) com a produção (gramas/planta). Os melhores resultados foram obtidos com as variáveis HAD e HAA, com coeficientes de determinação (R 2 ) variáveis entre 0,19 e 0,56 para HAD e 0,23 e 0,49 para HAA. Quando as variáveis HLAI e HRI foram relacionadas com a produção, os coeficientes de determinação variaram entre 0,24 e 0,57 para HLAI e 0,28 e 0,56 para HRI. A partir das avaliações semanais de HLAI e HRI foram realizadas regressões lineares entre estas variáveis e a produção (gramas/planta). Os coeficientes angulares foram relacionados com os estádios de desenvolvimento observando-se a estabilização das curvas entre os estádios R5-R8 para o patossistema ferrugem - feijão e entre os estádios V4-R8 para o patossistema mancha angular - feijão para HLAI e HRI. Nesses experimentos foram também realizadas avaliações do Índice de Área Foliar (LAI) utilizando-se medições diretas (avaliações manuais) e indiretas com ceptômetro. As medições obtidas com o este equipamento apresentaram sensibilidade suficiente para captar as variações no índice de área foliar sadio e portanto podem ser usadas em sistemas de manejo integrado da ferrugem e da mancha angular do feijoeiro. / Four trials were carried out on dry beans (Phaseolus vulgaris), variety 'Carioca' with goal to verify the possibility of implementation of an integrated management system for rust and angular spot after the application with of oxycarboxin (Hokko Plantvax 750 - 700 g/ha) and trifenil stannic hydroxide (Mertin â - 660 ml/ha) fungicides, applied in different timings. The damage quantification in these pathosystems were done analyzing the possible existing relation among the integral variables AUPDC (Area Under Disease Progress Curve), HAD (Healthy Area Duration) and HAA (Healthy Area Absorption) and its correspondents HLAI (Healthy Leaf Area Index) and HRI (Healthy Radiation Intercept) with yield (grams/plant) through linear and non linear regression. The best results were obtained using the variables HAD and HAA with the determination coefficients (R 2 ) from 0.19 to 0.56 for HAD and 0.23 to 0.49 for HAA. When HLAI and HRI were related with yield, the determination coefficient ranged from 0.24 and 0.57 for HLAI and 0.28 to 0.56 for HRI. From weekly assessments of HLAI and HRI, linear regression analysis were done between those variables and yield (grams/plant). The angular coefficient were related with the different crop stages and the stability of curves was observed between R5-R8 stages for rust - dry bean pathosystem and between V4-V8 stages for angular spot – dry bean pathosystem when HLAI and HRI were analyzed. In these experiments, Leaf Area Indice (LAI) was also assessed with direct (manual) and indirect measures with a ceptometer. The measures obtained using this set provided necessary sensibility to catch HLAI variation and, therefore, may be used in an integrated management system of rust and angular spot in dry beans.

O crescente interesse pelo uso de combustíveis renováveis nos últimos anos fez com que culturas oleaginosas, como a mamona, se tornassem importante objeto de estudo. No entanto, para a instalação de campos desta cultura, é imprescindível sementes de boa qualidade. Como não existem defensivos químicos registrados para a ricinocultura, avaliou-se o efeito de tratamentos fungicidas no tratamento de sementes de mamona (Ricinus communis L.), com produtos fungicidas recomendados para sementes de outras espécies oleaginosas. Três lotes do cv. IAC-2028 (provenientes, respectivamente, dos racemos primário, secundário e terciário) e dois lotes do cv. Guarani (lotes comerciais com todos os racemos) foram tratados com os fungicidas: Captan 500 TS, Derosal Plus, Vitavax-Thiram 200 SC, Maxim XL, Thiram 480 TS, Captan 500 TS + Derosal, Vitavax-Thiram 200 SC + Terraclor 750PM, Fegatex e Trichodermil EP. As amostras foram armazenadas em sacos de papel Kraft por um período de seis meses em condições não controladas de temperatura e umidade relativa do ar. As avaliações contemplaram o potencial sanitário e fisiológico das sementes assim que as sementes foram tratadas e após seis meses de armazenamento. O teste de sanidade foi conduzido pelo método de incubação em papel de filtro sem congelamento e a avaliação foi realizada no décimo dia. Os resultados dos testes de sanidade, de germinação, primeira contagem de germinação, envelhecimento acelerado, emergência de plântulas em campo e análise computadorizada de plântulas (SVIS®), mostraram que a maioria dos tratamentos fungicidas reduziram a incidência de patógenos associados às sementes, com destaque para os tratamentos Vitavax-Thiram+Terraclor, seguido de Vitavax-Thiram, Captan+Derosal, Derosal Plus, Captan e Thiram. A análise computadorizada de plântulas apresenta eficiência equivalente aos testes de primeira contagem de germinação e de emergência de plântulas em campo. O teste de raios X é eficiente para avaliar a morfologia interna das sementes e seus reflexos no potencial fisiológico. / The rising interest in using biodiesel as an alternative energy source is turning some oleaginous crops, like castor bean (Ricinus communis L.), become very important. Although its importance, castor bean yields must have high quality seeds. There are no registered chemical products for castor bean crop; this study aimed to verify fungicide treatments in castor bean seeds (Ricinus communis L.), with registered and recommended fungicides for other oil crops species. Three seed lots of the cultivar IAC 2028 (from the first, second and third raceme, respectively) and two seed lots of the cultivar Guarani (commercial lots with the three racemes mixed) were treated using the fungicides: Captan 500 TS, Derosal Plus, Vitavax-Thiram 200 SC, Maxim XL, Thiram 480 TS, Captan 500 TS + Derosal, Vitavax-Thiram 200 SC + Terraclor 750PM, Fegatex and Trichodermil EP. Seeds were stored in paper bags for six months in uncontrolled environment, and the evaluations contemplate the sanitary and physiological quality after seed treatment and after a period of six month storage. The sanitary test was carried out by the blotter incubation method with no freezing and evaluated after ten days. Results of the sanitary test, germination, first count of germination, accelerated aging, seedling emergence in the field and seed vigor imaging system (SVIS®), showed that most of the fungicide treatments reduced fungi incidence of pathogens associated to castor bean seeds. The most efficient fungicides in controlling fungi associated to the seeds, without any damage to the physiological quality, were Vitavax-Thiram+Terraclor, followed by Vitavax-Thiram, Captan+Derosal, Derosal Plus, Captan and Thiram. The computer analysis system has efficiency equivalent to first count germination and seedling emergence in the field. The X-ray test is effective in evaluating the internal morphology of castor bean seeds and its reflection on the physiological potential.

Philosophiae Doctor - PhD / We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill™, Rovral™, Terminator™ and Teldor™ at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral™ significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit. / South Africa

Philosophiae Doctor - PhD / We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill™, Rovral™, Terminator™ and Teldor™ at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested alone and in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. Africana and Rovral™ significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface

An assessment of the effect that conventional storage structures, used by smallscale farmers in northern Kwa-Zulu Natal and southern Mozambique, had on germination and vigour of maize seeds was conducted. The survey confirmed that the methods of storing the seed decreased the quality of the maize seeds. Storing maize in the field was good as a short-term solution as initial germination was 100%. Following storage at suboptimum conditions, germination dropped to 25.3%. Commercially treated maize seeds were compared to the test samples collected. After storage, the commercially treated seeds maintained a germination percentage above 75. Untreated maize seeds were treated with fungicides at the recommended dosages. Thereafter the seeds were subjected to germination and vigour tests according to methods outlined by the International Seed Testing Association. All treatments maintained percentage germination above 75. Apron® XL had the highest percentage germination of 83. This trend was also found following the cold test and greenhouse emergence. None of the treatments differed significantly from the control. In this study none of the treatments caused major imbibition damage as indicated by the percentage weight increase and the low leachate conductivity (1012-1271 ìScm-1g-1). The effect of accelerated ageing (AA, 2 and 4 days) and long-term storage (3 and 6 months) on germination and vigour of treated maize seeds was investigated. In the untreated control and treatments there was a gradual decrease in germination following ageing and storage of the seeds. Apron® XL failed to germinate after 3 months. The decrease in germination was mirrored by the leachate conductivity readings. Thiram was the only treatment to maintain germination after 6 months storage. The seeds were planted in two greenhouse trials to assess the performance of the treatments in vivo. The first trial evaluated the emergence and second the emergence and control of Fusarium graminearum. Results from the first trial showed that following 2 d AA, seeds treated with Thiram had the highest percentage emergence (70.7) followed by Celest® XL (68) and the untreated control (62.7). Following inoculation, a similar trend was seen for the treatments and the untreated control. In relation to the percentage seedlings emerged, the control had the highest percentage diseased seedlings. Celest® XL had the lowest percentage diseased seedlings (10, 2 and 1) but failed to germinate after 6 months storage. Thiram was the only treatment to emerge after 6 months storage. The ultrastructural changes in embryonic roots of the untreated control, Celest® XL and Apron® XL were investigated using transmission electron microscopy. These seeds were subjected to 48 hr rapid imbibition and 2 d AA. The most obvious difference between the untreated control, Apron® XL and Celest® XL was the number and position of the vacuoles. In contrast the lipid layer was still attached to the cell wall in the Apron® XL and Celest® XL treatments but in the untreated control they appeared more concentrated in the cytoplasm. This study proved that Thiram was the best treatment among the fungicides tested. However, these results need to be confirmed using a larger range of maize seed lots. / Thesis (PhD)--University of Pretoria, 2011. / Microbiology and Plant Pathology / unrestricted