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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

Produtos naturais no controle da antracnose e na qualidade pós-colheita de mangas 'Palmer' /

Guimarães, João Emmanuel Ribeiro. January 2016 (has links)
Orientador: Ben-Hur Mattiuz / Banca: Renata Moreira Leal / Banca: Rita de Cássia Panizzi / Banca: Cristiane Maria Ascari Morgado / Banca: Juliana Sanches / Resumo: O objetivo do trabalho foi avaliar produtos alternativos, considerados naturais, como o extrato de própolis verde e óleos essenciais, no controle pós-colheita da antracnose em mangas 'Palmer'. Foram extraídos dez óleos essenciais de plantas e avaliados, inicialmente, quanto ao potencial antifúngico contra o Colletotrichum gloeosporioides in vitro. Dentre os óleos testados, os de Thymus vulgaris, Cymbopogon citratus e Eucalyptus globulus foram selecionados pelos seus destacados efeitos inibitórios. Na etapa in vitro foram realizados quatro experimentos, em que foram testadas concentrações de extrato de própolis verde e dos óleos, utilizando seis repetições por tratamento. Na etapa in vivo, foram realizados quatro experimentos em que mangas 'Palmer, foram imersas em cera associada a diferentes concentrações de extrato de própolis verde e dos três óleos essenciais selecionados na etapa anterior. Após a secagem e formação dos revestimentos, os frutos tratados com própolis foram armazenados 12 ºC por 12 dias e mais 3 dias em temperatura de ambiente (22± 2 ºC e 65± 5% UR), e os tratados com óleos essenciais por 14 dias sob refrigeração, e por mais 3 dias a temperatura de ambiente. Os resultados foram submetidos à análise de variância e o efeito dos tratamentos, quando significativo, por meio do Teste F. As médias foram comparadas pelo teste de Tukey (P≤0,05). O própolis verde a partir de 2%, o óleo de capim-limão a partir de 250 ppm e o de tomilho a partir de 10 ppm, se mostraram e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective was to evaluate alternative products, considered natural such as green propolis extract and essential oils, in the post-harvest control of anthracnose in 'Palmer' mangos. Ten essential oils from plants were extracted and evaluated, initially, for their potential as antifungal agents against Colletotrichum gloeosporioides in vitro. Among the oils tested, the Thymus vulgaris, Cymbopogon citratus and Eucalyptus globulus were selected for their outstanding inhibitory effects. In the in vitro stage four experiments were conducted, in which green propolis extract and oil concentrations were tested using six replicates per treatment. In the in vivo phase, four experiments were performed in which 'Palmer' mangos were dipped in wax associated with different concentrations of green propolis extract and the three essential oils selected in the previous step. After the drying process and formation of coatings, the fruits treated with propolis were stored at 12°C for 12 days and then another 3 days at room temperature (22 ± 2°C and 65 ± 5% RH), and those treated with essential oils were stored for 14 days under refrigeration and for 3 days at room temperature. The results were subjected to variance analysis and a review of the effect of treatments, when significant, by test F. Means were compared by Tukey test (p ≤ 0.05). The green propolis from 2%, lemongrass oil from 250 ppm and thyme from 10 ppm were effective in controlling the growth of C. gloeosporioides in vitro. Comm... (Complete abstract click electronic access below) / Doutor
232

Efeitos dos subprodutos da aroeira e do biofilme a base de quitosana na pós-colheita e controle da antracnose em goiabas ‘Paluma’

Santos, Marília Cavalcante dos 28 February 2012 (has links)
Guava is cultivated in many parts of the world, but the high perishability and the incidence of diseases such as anthracnose limits its commercialization. The challenge to the method used to attempt to solve these problems, the use of chemicals, has instigated the conduct of research with products. Thus, plantas have been studied mant times have active substances with antimicrobial properties, among them aroeira that is widely used in folk medicine and its potencial for the use in agricultura are being targeted studies. Another alternative is the use of coatings based on polymers such as chitosan that in addition to prolonging the shelf-life also presents potencial antifungal. This study to determine the yeld of aqueous extract and hydrolate mastic and the main chemical compounds contained, to evaluate the antifungal effect of hydrodistillation byproducts on in vitro development of the fungus Colletotrichum gloeosporioides and test biofilm-base chitosan for promote increased service life and control the attack of anthracnose in guavas Paluma . The aqueous extract end hydrolate were obtained by hydrodistillation of leaves and seeds at different times. For the in vitro antifungical power of aroeira in C. gloeosporioides concentrations used were 5, 10, 15, 20, 25 and 30% aqueous extraxt, 10, 15, 20 and 25% hydrolate and 2μL fungicide. In vivo test, guavas were inoculated with the pathogen were for 1 minute in chitosan solutions 2, 3 and 4% and subjected to chemical and physical assessments every 4 days storage totaling 12. It was observed that the time of hydrodistillation did not influence the yeld of the aqueous extract and hydrolate, indicating 2,5h for extraction. Larger amounts of hidrolact were obtained from levaes of aroeira, while the yield of the extract was not influenced by the plant. Unable to determine the compounds existing in the hydrolate aroeira. The fungus developed in all treatments with respect cotonoso except in fungicide Captan® (2μL). The aqueous extract and hydrolate aroeira showed no fungicidal properties of inhibiting the development of in vitro concentrations used in Colletotrichum gloeosporioides is not recommended to control of this fungus. The guavas coated with chitosan 3 and 4% had delayed ripening being evidenced by the high firmness, color maintenance from the pulp and peel, slight increase of soluble solids and vitamin C in addition to having constant pH. A 2% chitosan was not as efficient when compared to other concentrations. The fruits control and fungicide were not fit for consumption for 12 days due to the rapid maruration and incidence of anthracnose. All concentrations of chitosan were efficient in controlling the fungus. / A goiaba é cultivada em várias partes do mundo, porém a alta perecibilidade e a incidência de doenças como a antracnose limitam a sua comercialização. A contestação do método mais utilizado para tentar solucionar tais problemas, o uso de produtos químicos, tem instigado a realização de pesquisas com produtos naturais. Assim, as plantas vêm sendo estudadas por muitas vezes possuírem substâncias ativas com propriedades antimicrobianas, dentre elas a aroeira que é amplamente utilizada na medicina popular e suas potencialidades quanto ao uso na agricultura estão sendo alvo de estudos. Outra alternativa é o uso de revestimentos a base de biopolímeros como a quitosana que além de prolongar a vida pós-colheita também apresenta potencial fungitóxico. Este trabalho teve como objetivos determinar o rendimento do extrato aquoso e hidrolato de aroeira e os principais compostos químicos contidos, avaliar o efeito fungitóxico destes subprodutos da hidrodestilação no desenvolvimento in vitro do fungo Colletotrichum gloeosporioides e testar biofilmes a base de quitosana para promover o aumento da vida útil e controlar o ataque da antracnose em goiabas Paluma . O extrato aquoso e o hidrolato foram obtidos por hidrodestilação de folhas e sementes em diferentes tempos. Para o ensaio in vitro do poder fungitóxico da aroeira em C. gloeosporioides foram utilizadas as concentrações 5, 10, 15, 20, 25 e 30% de extrato aquoso; 10, 15, 20 e 25% de hidrolato e 2μL de fungicida. No ensaio in vivo as goiabas foram inoculadas com o patógeno, imersas por 1 minuto em soluções de quitosana a 2, 3 e 4% e submetidas a avaliações físicas e químicas a cada 4 dias totalizando 12 de armazenamento. Observou-se que os tempos de hidrodestilação não influenciaram o rendimento do extrato aquoso e do hidrolato, indicando-se 2,5h para extração. Maiores quantidades de hidrolato foram obtidas a partir de folhas de aroeira, enquanto que o rendimento do extrato também não foi influenciado pela parte da planta. Não foi possível determinar os compostos existentes no hidrolato da aroeira. Os fungos desenvolveram-se em todos os tratamentos com aspecto cotonoso exceto no fungicida Captan® (2μL). O extrato aquoso e hidrolato de aroeira não apresentaram propriedade fungicida para a inibição do desenvolvimento do in vitro do Colletotrichum gloeosporioides nas concentrações utilizadas não sendo recomendados para controle deste fungo. As goiabas revestidas com quitosana 3 e 4% tiveram seu amadurecimento retardado sendo evidenciado pela alta firmeza, manutenção da coloração tanto da polpa quanto da casca, leve incremento de sólidos solúveis e vitamina C além de apresentarem pH constante. Os frutos controle e fungicida não se encontravam aptos para o consumo aos 12 dias em função do rápido amadurecimento e incidência de antracnose. Todas as concentrações de quitosana foram eficientes no controle do fungo.
233

Influência da temperatura e período de molhamento no desenvolvimento da antracnose e nas características físico-químicas da banana

PESSOA, Wagner Rogério Leocádio Soares 28 February 2005 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-23T15:49:15Z No. of bitstreams: 1 Wagner Rogerio Leocadio Soares Pessoa.pdf: 1202325 bytes, checksum: 24359deb95d67f77dc4011b48213d142 (MD5) / Made available in DSpace on 2017-03-23T15:49:15Z (GMT). No. of bitstreams: 1 Wagner Rogerio Leocadio Soares Pessoa.pdf: 1202325 bytes, checksum: 24359deb95d67f77dc4011b48213d142 (MD5) Previous issue date: 2005-02-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The banana is the second largest fruit more consumed in the world, being the fresh fruit that detain the largest market. Brazil blunts as second largest producer of the fruit. In Brazil the varieties Silver and Pacovan approximately 60 % of the cultivate area. However, several phytopathological factors such as fungi and bacteria can cause the banana crop losses that could reach up to 40 %. Among these factors, anthracnose caused by Colletotrichum musae, deserve special attention in harming the commercialization and the consumption in natura. Because of the importance of this disease in banana and the lack of information on the subject, this work had two objectives: 1) study the influence of inoculation methods, different temperatures associates to different wetness period on the development of the disease; 2) verify alterations physicalchemistry happened in the banana fruits. The fruits were inoculated with 17 isolated of C. musae in two ways using PDA disk containing structures of the pathogen and suspension of conidia 4x 106 conidia / mL. The banana fruits were inoculated with the pathogen in the presence or not of artificial wounds. All C. musae isolates were pathogenic independently of the inoculation method used. Lesions could be observed in artificially wounded fruits independently of the inoculation method used (disk and suspension). In order to access the influence of temperature and wetness period, the isolates MAG2, SFV1 and FSA of C. musae were used isolated. These isolates were chosen because they show a wide rage of aggressiveness in the pathogenicity test. The bananas fruits were inoculated and incubated in the temperatures of 10, 15, 20, 25 and 30 oC with periods of wetness of 0, 12, 24 and 36 h, during five days. Temperatures of 20, 25 and 30 oC and with increasing wetness periods favored the development of lesions. Largest lesions wereobserved in the temperatures around 25 to 30 oC and 36 h of wetness period. Several physicalchemical alterations could be observed in the fruits during thexperiment: 1) there was an increase in the banana fruit humidity as the temperature and the wetness period increased, 2) They reach its highest pH value at 30 oC independently of the wetness period, 3) The largest ATT for the isolates SFV and MAG occurred at the same temperature of 25 oC, with wetness period of 12 and 24 h, respectively. The largest ATT value for the isolate FSA occurred at the temperature of 15 oC associated to the wetness period of 36 h, 4) Maximum SST occurred at temperature around 20 oC independent of the wetness period, 5) The largest potassium levels was reach at the temperature of 10 oC with wetness period of 24 h for SVF and MAG and without wetness period in FSA, 6) The total sugars content increased with the elevation of the temperature, decrease as the temperature approached of 30 oC, independent of the wetness period and the isolated of C. musae used. / A banana é a segunda fruta mais consumida no mundo, sendo (a fruta fresca neste contexto detentora de maior mercado no mundo) o Brasil segundo maior produtor, utilizando as variedades Prata e Pacovan em aproximadamente 60% de sua área cultivada. Entretanto, diversos fatores podem ocasionar perdas na produção, podendo chegar à ordem de 30 a 40%. Entre estes fatores encontram-se fungos e bactérias, merecendo destaque especial na pós-colheita a antracnose, causada por Colletotrichum musae, prejudicando a comercialização e o consumo in natura. Diante da importância desta doença na banana e a carência de informações sobre o assunto, este trabalho teve por objetivos, estudar a influência de métodos de inoculação, diferentes temperaturas associadas a distintos períodos de molhamento sobre o desenvolvimento da doença, e sua influência nas características físicoquímica. Avaliaram-se 17 isolados de C. musae, utilizando-se dois tipos de inóculo: disco de meio BDA contendo estruturas do patógeno e suspensão de conídios 4x106 conídios/mL, em duas formas de inoculação: com e sem ferimentos. Todos os isolados de C. musae mostraram-se patogênicos independente do tipo de inóculo utilizado. As lesões ocorreram nas frutas com ferimento, independente do tipo de inóculo (disco e suspensão). Para o estudo da influência da temperatura e período de molhamento, utilizaram-se três isolados do patógeno MAG2, SFV1 e FSA, por mostraram-se mais agressivo, intermediário e menos agressivo, respectivamente, no teste de patogenicidade. Asfrutas foram inoculadas e incubadas nas temperaturas de 10, 15, 20, 25 e 30oC e períodos de molhamento de 0, 12, 24 e 36 h, por cinco dias. As temperaturas em torno de 20, 25 e 30oC independente do período de molhamento favoreceram um maior desenvolvimento de lesões. As alterações físico-química mostraram que houve um aumento de umidade da fruta à medida que a temperatura e o período de molhamento aumentavam. Valores mais elevados de pH ocorreram em torno da temperatura de 30oC, independente do período de molhamento. Em relação a Acidez Titulável Total (ATT) para o isolado SFV1 e MAG2 ocorreu na temperatura ao redor de 25oC, com período de molhamento de 12 e 24 h, respectivamente, e para o isolado FSA ocorreu ao redor da temperatura de 15oC associado ao período de molhamento de 36 h. O teor de Sólidos Solúveis Totais (SST) ficou em volta de 20oC independente do período de molhamento. A temperatura ao redor de 10oC favoreceu a elevação no nível de potássio das frutas, associado ao período de molhamento de 24 h, em frutas inoculadas com os isolados SVF1 e MAG2, e 0 hora quando utilizou-se o isolado FSA. Os teores de açúcares totais aumentaram com a elevação da temperatura, declinando à medida que esta se aproximava de 30oC, independente do período de molhamento e isolados de C. musae.
234

Produção e caracterização bioquímica de enzimas lignocelulolíticas fúngicas e sua aplicação na sacarificação de biomassa lignocelulósica / Production and biochemical characterization of fungal enzymes lignocellulolytic and its application in saccharification of biomass lignocellulosic

Ana Lucia Ribeiro Latorre Zimbardi 05 August 2014 (has links)
Atualmente há grande interesse no desenvolvimento de processos enzimáticos eficientes para a hidrólise da biomassa lignocelulósica. O objetivo deste trabalho foi a otimização da produção por fermentação em estado sólido e a caracterização bioquímica, no extrato bruto, das -glucosidases, -xilosidases e xilanases produzidas por Colletotrichum graminicola e das lacases produzidas por Pycnoporus sanguineus. Também foi avaliado o potencial de aplicação dos extratos obtidos em coquetéis enzimáticos para a sacarificação de resíduos agroindustriais. A otimização das condições de cultivo, empregando a Metodologia de Superfície de Resposta, levou à produção de 159,3 ± 12,7 U g-1, 125,88 ± 6,4 U g-1, 378,1 ± 23,3 U g-1 e 138,6 ± 6,4 U g-1 de -glucosidases, -xilosidases, xilanases e lacases, respectivamente. Os meios de cultivo empregados foram constituídos por farelo de trigo suplementado com resíduos agroindustriais. Todas as enzimas produzidas apresentaram pH e temperatura ótimos de reação de 4,5-5,0 e 65ºC, respectivamente, bem como boa estabilidade térmica e ao pH. O coquetel composto pelos extratos brutos obtidos em condições otimizadas para a produção de xilanases (ECg) e lacases (EPs), em mistura com um extrato bruto de Trichoderma reesei rico em celulases (ETr) foi muito eficiente na sacarificação de palha de cana e papelão, sem pré-tratamento, atingindo rendimentos de 41,4 e 71,1% em glicose, respectivamente. Além disso, este coquetel foi mais eficiente na sacarificação de bagaço de cana explodido e in natura bem como de palha de cana in natura, quando comparado a um coquetel contendo celulases comerciais (Celluclast®) em mistura com ECg e EPs. Visando estudos futuros da ação individual de cada enzima sobre a biomassa, foi purificada uma -glucosidase majoritária de C. graminicola. A enzima mostrou temperatura e pH ótimos de reação de 5,0 e 65ºC, respectivamente, boa estabilidade térmica e ao pH, além da estimulação por xilose, propriedade muito interessante para emprego em coquetéis mistos de celulases e xilanases. Os resultados encontrados sugerem que as enzimas produzidas por C. graminicola e P. sanguineus, assim como os coquetéis enzimáticos avaliados, apresentam características muito interessantes para aplicações biotecnológicas, particularmente em processos de sacarificação da biomassa para obtenção de etanol celulósico. / There is currently a great interest in developing efficient processes for the enzymatic hydrolysis of lignocellulosic biomass. The objective of this study was the optimization of the culture conditions for the production of -glucosidases, xylanases and -xylosidases by Colletotrichum graminicola and laccases by Pycnoporus sanguineus under solid state fermentation, followed by the biochemical characterization of the enzymes in the crude extracts. The potential of application of the extracts to compose enzyme cocktails for the saccharification of agroindustrial residues was also investigated. Optimization of the culture conditions using the Response Surface Methodology led to the production of 159.3 ± 12.7 U g - 1, 125.88 ± 6.4 U g- 1, 378.1 ± 23.3 U g - 1 and 138.6 ± 6.4 U g - 1 of -glucosidases, -xylosidases, xylanases and laccases, respectively. The culture media employed consisted mainly of wheat bran, supplemented with agroindustrial residues. All enzymes produced showed optimum pH and temperature of 4.5-5.0 and 65° C, respectively, as well as good thermal and pH stability. A cocktail composed of the crude extracts obtained under optimized conditions for the production of xylanases (ECg) and laccases (EPs), mixed with a Trichoderma reesei crude extract (ETr), rich in cellulases, was highly efficient for the saccharification of sugarcane trash and cardboard, without pretreatment, reaching yields of 41.4% and 71.1% in glucose, respectively. Moreover, this cocktail was more efficient than a cocktail composed of commercial cellulases (Celluclast ®) in combination with ECg and EPs for the saccharification of raw and steam exploded sugarcane bagasse, as well as raw sugarcane trash. Aiming future studies on the individual action of each enzyme on biomass, a majoritary -glucosidase from C. graminicola was purified. The enzyme showed optima of temperature and pH of 5.0 and 65° C, respectively, good thermal and pH stability, as well as stimulation by xylose, a very interesting property for its application in mixed cellulase-xylanase cocktails. The results suggested that the enzymes produced by C. graminicola and P. sanguineus, as well as the cocktails employed in this study, have good potential for biotechnological applications, particularly in biomass saccharification processes for cellulosic ethanol production.
235

Indução de resistência a antracnose do feijoeiro por frações de filtrato de cultura e extrato de micélio de Trichoderma longibrachiatum

Dildey, Omari Dangelo Forlin 12 May 2017 (has links)
Submitted by Helena Bejio (helena.bejio@unioeste.br) on 2017-11-22T17:51:25Z No. of bitstreams: 2 Omari DF Dildey 2017.pdf: 1365505 bytes, checksum: cb552699fd45b8b24d3b14fefe36a796 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-11-22T17:51:25Z (GMT). No. of bitstreams: 2 Omari DF Dildey 2017.pdf: 1365505 bytes, checksum: cb552699fd45b8b24d3b14fefe36a796 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-05-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study aimed to purify by chromatography elicitors from Trichoderma longibrachiatum culture filtrate and mycelium extract and to test them in phytoalexin phaseolin inducing and resistance induced to anthracnose in common bean. The sodium phosphate buffer at 0.05 M (SPB) was used as the control treatment and the ASM (Acibenzolar-S-Metil) was used as the standard induction treatment. Ion Exchange Chromatography (IEC) and Gel Filtration Chromatography (GFC) were performed to separate fractions with eliciting power from the culture filtrate (CF) and T. longibrachiatum mycelium extract (TME). For the purification of elicitors by IEC, from GFC, it were obtained one glycidic and five glycoproteins fractions, totaling six fractions. For purification from TME, it were obtained three protein, one glycidic and two glycoproteins fractions, totaling six fractions. In both, were obtained twelve fractions from IEC. These, in turn, were purified in GFC, being obtained a total of thirty seven fractions. Among these, there were fourteen fractions of TME were classified according to their nature, being three proteins, two glycogen and nine glycoproteins. There were twenty-three fractions from TME, wich were classified according to their nature, being four proteins, nine glycogen and ten glycoproteins. Of the fractions purified in CFG from FTC and TME, eight presented phaseolin inducer potential (F17, F23, F25, F27, F31, F38 and F46). The 10 treatments consisted of the eight fractions and two controls: ASM and control (TAP). Treatments were applied in one of the primary leaves (treated leaf (TL)), and the other primary leaf was not treated (untreated leaf (UL)) to verify the systemic effect. Three leaf samples were taken for determination of enzymatic activity: before applying the fractions, after application of the fractions and after the pathogen inoculation. The defense enzyme analysis was performed for Peroxidase (POX), Polyphenoloxidase (PFO), Catalase (CAT), Phenylalanine ammonia-lyase (PAL) and β-1,3-glucanase (β-GASE). At the end, it was performed an evaluation of severity in the primary leaf of common bean, on the fifth day after inoculation. The in vivo test data were subjected to analysis of variance. The purification of samples from FTC and EXM of T. longibrachiatum, from IEC and GFC indicated fractions with the presence of eliciting molecules. The fractions F17, F23 and F25 from FTC and F27, F29, F31, F38 and F46 from EXM were able to induce phaseolin synthesis in common bean hypocotyls. The POX, PFO and β-GASE Increased when applied in the TL after application of the fractions and after inoculation of the pathogen. The fractions did not alter CAT and FAL enzymatic activity. The fractions F17, F23 and F27 reduced the anthracnose severity in the local effect. / O trabalho teve por objetivo purificar por cromatografia moléculas eliciadoras a partir de filtrado de cultura e extrato de micélio de Trichoderma longibrachiatum e testá-las na indução de fitoalexina faseolina e com potencial indutor de resistência contra antracnose no feijoeiro. O tampão fosfato de sódio 0,05 M (TAP) foi utilizado como tratamento controle e ASM (Acibenzolar-S-Metil) foi utilizado como tratamento padrão de indução. Cromatografia de troca iônica (CTI) e cromatografia de filtração em gel (CFG) foram realizadas para separar frações com poder eliciador a partir de filtrado de cultura (FTC) e extrato de micélio (EXM) de T. longibrachiatum. Para a purificação de eliciadores por CTI, a partir de FTC, foram obtidos uma fração glicídica e cinco glicoproteicas, total de seis frações. Para a purificação a partir de EXM, forma obtidos três frações proteicas, uma glicídica e duas glicoproteicas, total de seis frações, em ambos foi totalizado doze frações obtidas por CTI. Estas, por sua vez, foram purificadas em CFG, sendo obtidos um total de trinta e sete frações. Entre essas, quatorze frações para FTC, as mesmas foram classificadas de acordo com sua natureza, sendo três proteicas, duas glicídicas e nove glicoproteicas. E vinte e três frações para EXM, as mesmas foram classificadas com sua natureza, sendo quatro proteicas, nove glicídicas e dez glicoproteicas. Das frações purificadas na CFG a partir de FTC e EXM, oito apresentaram potencial indutor de faseolina (F17, F23, F25, F27, F31, F38 e F46. Os 10 tratamentos constituíram de oito frações e dois controles: ASM e controle (TAP). Foram aplicados os tratamentos em uma das folhas primária (folha tratada (FT)), sendo que outra folha primária não recebeu tratamento (folha não tratada (FNT)) para verificar o efeito sistêmico. Foram realizadas três coletas de folhas para determinação da atividade enzimática, antes da aplicação das frações, depois da aplicação das frações e coleta após a inoculação do patógeno. Foi realizada análise enzimática (peroxidase (POX), polifenoloxidase (PFO), catalase (CAT), fenilalanina amônia-liase (FAL) e β-1,3-glucanase (β-GASE)) e ao final, realizada avaliação de severidade no quinto dia após a inoculação da folha primária de feijoeiro. A purificação de amostras provenientes de FTC e EXM de T. longibrachiatum, por CTI e CFG indicaram frações com presença de moléculas eliciadoras. As frações F17, F23 e F25 de origem FTC e F27, F29, F31, F38 e F46 de origem EXM foram capazes de induzir a síntese de faseolina em hipocótilos de feijoeiro. A atividade de POX, PFO e β-GASE aumentou quando aplicado na FT após a aplicação das frações e após a inoculação do patógeno. As frações não alteraram a atividade enzimática de CAT e FAL. As frações F17, F23 e F27 reduziram a severidade da antracnose no efeito local.
236

Podridão floral dos citros: definição do limiar de ação para controle químico e monitoramento da sensibilidade de isolados a tebuconazol e trifloxistrobina / Postbloom fruit drop: definition of the action threshold for chemical control and survey of isolates sensitivity to tebuconazole and trifloxystrobin

André Bueno Gama 17 July 2017 (has links)
A citricultura brasileira se destaca no mercado global de citros, apresentando altos valores de produção e produtividade. Dentre as diversas doenças que afetam a cultura, a podridão floral dos citros (PFC) vem ganhando destaque com o deslocamento de áreas produtoras para regiões mais favoráveis à ocorrência desta doença. A PFC, causada por espécies dos complexos Colletotrichum acutatum e C. gloeosporioides, é especialmente problemática em anos de temperaturas amenas e alta umidade. Os citricultores realizam pulverizações preventivas para o controle da PFC todos os anos, embora condições climáticas favoráveis à doença ocorram apenas ocasionalmente. Além do impacto econômico, as frequentes pulverizações com fungicidas aumentam a pressão de seleção sobre isolados resistentes, o que pode interferir na eficiência do controle químico. A utilização de sistemas de previsão de epidemias pode evitar que pulverizações desnecessárias de fungicidas sejam realizadas caso não haja condições favoráveis à ocorrência da doença. Para o desenvolvimento destes sistemas, é imprescindível determinar um limiar de ação para a aplicação de fungicidas nos pomares. Dessa forma, o presente trabalho teve por objetivos: (i) estabelecer um limiar de ação para a aplicação de fungicidas com base na germinação de conídios de C. acutatum que permita o controle a doença igualmente ou de forma mais eficiente do que o sistema de pulverização adotado pelos citricultores do sudoeste paulista; (ii) caracterizar a sensibilidade de isolados dos complexos C. gloeosporioides e C. acutatum à trifloxistrobina e ao tebuconazol in vitro e molecularmente, para identificar possíveis mudanças de sensibilidade das espécies a estes fungicidas. Para a definição do limiar de ação, tratamentos baseados em índices de risco foram comparados ao tratamento testemunha e ao calendário fixo de aplicações, usualmente adotado pelos produtores. A aplicação de fungicidas quando limiar de 15% de germinação de conídios era atingido, foi eficiente em controlar a doença e reduzir o número de aplicações de fungicidas. Nos ensaios de sensibilidade a fungicidas dois métodos foram utilizados para a determinação da CE50: o da diluição em gradiente espiral para trifloxistrobina e tebuconazol e o da inibição da germinação de conídios para a trifloxistrobina. Foram utilizados isolados coletados entre 1999 e 2016. A CE50 média da coleção de isolados de acordo com o método da diluição em gradiente espiral variou de 0,158 a 0,297 μg/ml e 0,1 a 0,182 μg/ml para trifloxistrobina e tebuconazol, respectivamente. Para a trifloxistrobina, de acordo com o método da inibição da germinação, a CE50 média foi de 0,002 μg/ml. Não foram verificadas características moleculares nem valores de CE50 atrelados à mudança de sensibilidade dos isolados. / Brazilian citrus industry represents a significant share in the global citrus market. Amongst several diseases that affect the crop, postbloom fruit drop (PFD) has been gaining prominence in Sao Paulo with the displacement of citrus areas to regions in which weather conditions are more favorable to the occurrence of this disease. PFD, caused by species of the complexes Colletotrichum acutatum and C. gloeosporioides, is especially problematic in years of mild temperatures and high humidity. Citrus growers spray the orchards preventively for PFD control every year, although favorable climatic conditions do not occur regularly. In addition to the economic impact, this practice increases the selection pressure of fungicide resistant isolates, and may decrease the efficiency of chemical control in a long term. The use of disease forecasting systems is able to prevent unnecessary fungicide sprays. For the development of such systems, it is essential to determine an action threshold for the application of fungicides in the orchards. The objectives of this work were: (i) to establish an action threshold for fungicide sprays based on the germination of C. acutatum conidia; (ii) to characterize the sensitivity of C. gloeosporioides and C. acutatum isolates to trifloxystrobin and tebuconazole in vitro and molecularly. Regarding the definition of the action threshold, treatments based on risk indices were compared to the control treatments and calendar based sprays, usually adopted by growers. The 15% conidia germination threshold was efficient in controlling the disease and reducing the number of fungicide applications. In the fungicide sensitivity tests, two methods were used to determine the EC50, the spiral gradient dilution for trifloxystrobin and tebuconazole, and the method of conidial germination inhibition for trifloxystrobin. Isolates collected between 1999 and 2016 were used. The mean EC50 of the isolate collection determined by the spiral gradient dilution method ranged from 0.158 to 0.297 μg/ml and from 0.1 to 0.182 μg/ml for trifloxystrobin and tebuconazole, respectively. Mean EC50 of trifloxystrobin estimated by the conidial germination inhibition method was 0.002 μg/ml. No mutations or EC50 values indicated shifts of fungicide sensitivity on the isolates.
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Characterization, epidemiology and control strategies for the anthracnose pathogen (Colletotrichum spp.) on cashew (Anarcardium occidentale L.) in Mozambique

Uaciquete, Americo January 2013 (has links)
The first confirmation of the presence of Colletotrichum gloeosporioides Penz. on cashew in Mozambique was based on a combination of observed symptoms, isolation and identification using basic morphological and molecular techniques. Anthracnose is now the second most important in the country, after powdery mildew caused by Oidium anacardii Noack. The present thesis represents a broad overview of the disease in Mozambique. The main focus of this study was thus to gather scientific information on the relevance of this disease in the country and through experimentation, generate recommendations that help farmers and decision makers to mitigate the disease pressure. The specific objectives of this study were as follows: - Provide a distinctive description of anthracnose symptoms on leaves through hostpathogen interaction studies in the laboratory. - Enhance current knowledge on the identity of Mozambican pathogen isolates, using DNA tools. - Assess the current anthracnose management practices, both at nursery and field level with a view to formulate timely, local and adequate management strategies. - Conduct experimental trials to select economically effective fungicides spraying programs for anthracnose disease management. ii - Search for variability and germplasm tolerance among dwarf and common cashew plant populations in Mozambique. By analyzing and integrating existing published literature on the subject, we successfully separated issues that concerned previously inaccessible information from those that reflect insufficient scientific knowledge. A survey was initiated to determine, the status of cashew anthracnose disease management practices in Mozambique. Subsequently, the information obtained was used to develop a national strategic framework for research and extension in the country. Areas identified as gaps were aligned with the main goals of this thesis and include: - Areas where scientific information lacked were identified. - The symptoms of the disease on leaves were successfully and distinctively distinguished from other common leaf diseases that simultaneously occur in orchards. - The pathogen isolates were identified using PCR techniques. The presence of Colletotrichum acutatum Simmonds was not confirmed at least not among the suspected and tested isolates. - Knowledge on the epidemiology of the disease was generated and its application for more effective disease management was successfully applied. - Effective fungicide applications and disease control programmes were developed for Colletotrichum gloeosporioides Penz.. - Appropriate nursery management strategies that reduce anthracnose disease development were developed. - Variability in germplasm reaction to the disease was demonstrated and therefore tolerant and susceptible genotypes were identified. - A technique for rapid and accurate evaluation of leaf anthracnose symptom grades was developed. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Microbiology and Plant Pathology / Unrestricted
238

Control of anthracnose (caused by Colletotrichum gloeosporioides s.l.) on mango in Senegal by fungicides and biofungicides

Diallo, Yaya 15 June 2016 (has links)
Senegal ranks second for mango production among West African countries and has the potential to competitively produce mangoes for the European market. Colletotrichum gloeosporioides Penz. and Sacc. has historically been considered the causal pathogen of anthracnose of mango and other fruits, but is now known to represent a species complex. Field trials to examine the efficacy of fungicides and biofungicides were conducted in southern and northern production regions of Senegal. In three southern trials, Sonata (Bacillus pumilus strain QST 2808), Serenade Optimum (Bacillus subtilis strain QST 713), and sodium molybdate provided 63%, 67% and 76% control of disease severity, respectively, whereas thiophanate methyl and azoxystrobin provided 77% and 78% control, respectively. Disease severities of all treatments were significantly lower than that of the control. Thiophanate methyl and azoxystrobin produced more disease-free mangoes (64 and 62%, respectively) than Serenade (49%), sodium molybdate (44%), and Sonata (38%). Differences within each trial were not statistically significant, but when all trials were combined, all treatments resulted in significantly more disease-free mangoes than the control. Among treatments, thiophanate methyl and azoxystrobin resulted in significantly more disease-free mangoes than Sonata. No results were obtained in the northern orchards due to an absence of disease development. Sequencing of the ITS gene region of 30 Colletotrichum isolates from mangoes from different regions in Senegal indicated that all belonged to the C. gloeosporioides species complex. Sequencing of the ApMat intergenic region identified all of them as most closely resembling C. siamense. / Master of Science in Life Sciences
239

Developing Novel Management Options for Pear Fire Blight and Apple Bitter Rot with Characterization of Apple European Canker in Virginia

Correa Borba, Matheus 27 June 2024 (has links)
In the realm of tree fruit cultivation, the management of various diseases affecting pome fruits like apples and pears is crucial for sustaining production. This study amalgamates findings from three distinct disease investigations to propose an integrated approach to their management. Firstly, in pursuit of mitigating shoot blight severity caused by Erwinia amylovora and preventing fire blight cankers on pear trees, a two-year evaluation was conducted. The study assessed the efficacy of preventive treatments, including foliar spray and trunk injection applications of Giant Knotweed Extract (RSE) alongside antibiotics. Results highlighted the effectiveness of RSE in controlling both shoot blight severity and canker incidence, offering a sustainable alternative to antibiotics. Secondly, in addressing the bitter rot of apples caused by Colletotrichum spp., eighteen fungicide treatments were evaluated over two years, focusing on newer fungicide options to mitigate fungicide resistance development. Fungicides such as Omega, Aprovia, Ferbam, Captan, Ziram, and Cabrio were proven reliable management tools, complementing the existing effective fungicides that growers heavily depend on. Lastly, the emergence of European canker (Neonectria ditissima) on cider apple cultivars was investigated. Molecular analysis confirmed the presence of N. ditissima as the causal agent, posing a significant threat to cider apple production. Koch's postulates were fulfilled through various tests, proving the pathogenicity of N. ditissima. Further research avenues, including genome sequencing were conducted to enhance understanding and control of a devastating pathogen like N. ditissima. Integrating findings from these studies proposes a comprehensive management strategy incorporating preventive spray programs, alternative fungicides, and pathogen identification to combat these diseases effectively, ensuring sustainable production of apples and pears in orchards. This holistic approach offers growers a multifaceted toolkit to manage diseases effectively, safeguarding apple and pear orchards' productivity and economic viability. / Master of Science in Life Sciences / In the world of growing apples and pears, keeping diseases under control is crucial for keeping orchards thriving and productive. We conducted studies on three endemic and emerging diseases aiming to create a well-rounded approach to managing them. First, we looked into ways to reduce the impact of shoot blight and fire blight cankers on pear trees caused by a devastating bacterium Erwinia amylovora. We tested the efficacy of preventive spray applications of plant extract of giant knotweed alongside antibiotics and found more sustainable alternatives to antibiotics that effectively control this disease. Next, we studied bitter rot disease in apples caused by many different species of fungi in Colletotrichum genus. We determined the efficacy of eighteen different biorational and synthetic fungicide spray programs over two years to find new options that can help prevent fungicide resistance development against currently available fungicides in the market. Several fungicides showed promise in managing this disease including Omega, Aprovia, Ferbam, Captan, Ziram and Cabrio, adding to the effective materials that growers already rely on. Lastly, we investigated the emergence of European canker on cider apple trees. This disease, caused by a fungus Neonectria ditissima, poses a serious threat to cider production. We confirmed the pathogen's identity and its capability of causing the disease in controlled experiments. We propose a comprehensive strategy for managing these diseases by including preventive spray applications of alternative materials and classic fungicides, combined with accurately identifying the pathogens. Our holistic approach provides growers with a range of tools to effectively protect their orchards, ensuring sustainable production of both apples and pears.
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Manejo de podridões pós-colheita em manga cv. Tommy Atkins pelo uso da radiação gama, atmosfera modificada e refrigeração

SANTOS, Alice Maria Gonçalves 25 February 2009 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-16T14:45:19Z No. of bitstreams: 1 Alice Maria Goncalves Santos.pdf: 828943 bytes, checksum: e2e058b935319e6ca5c5d01db52c323c (MD5) / Made available in DSpace on 2017-02-16T14:45:19Z (GMT). No. of bitstreams: 1 Alice Maria Goncalves Santos.pdf: 828943 bytes, checksum: e2e058b935319e6ca5c5d01db52c323c (MD5) Previous issue date: 2009-02-25 / In postharvest, the mango is predisposed to several diseases, including the complex known as stem-end rot fungus that has Lasiodiplodia theobromae as a major player in addition to rot by fusicocco (Fusicoccum parvum) and anthracnose caused by Colletotrichum gloeosporioides. The mangicultura is of great economic importance for Brazil, but has been losing ground with the losses that occur in post-harvest disease incidence mainly during transportation and storage, there is need to develop technologies that demonstrate effectiveness in delaying the senescence of fruits improving the marketing capability. Among the technologies we highlight the physical methods such as the use of gamma irradiation, cold storage and use of modified atmosphere. This study aimed to evaluate the three methods of physical control over the development of post-harvest mango and on the physico-chemical properties held for the treatments. For this, the fruit were inoculated with different firopatógenos and after 24 hours applied to gamma radiation doses of 0, 0.25, 0.35, 0.45 kGy, and as the Cobalt 60 source. The fruits were packed with PVC film with 380 mm x 10 microns in trays and kept under refrigeration at 13 º C for 15 days and after that period kept at room temperature, 25 ° C without the plastic film. We observed a reduction of disease development for the three fungi studied, reaching the full control of the disease when evaluating the development of anthracnose in mangoes that were subjected to higher dose of 0.45 kGy. Mangoes irradiated showed no significant differences for some parameters (ascorbic acid, total acidity (TTA), pH, total soluble solids (TSS), ratio (TSS / TTA), firmness and flesh color). Inoculated mangoes like C. gloeosporioides showed no significant changes to the physical and chemical properties, except for spots on the peel. The mangoes inoculated with L. theobromae and F. parvum showed no significant differences between the treatments that compromise the marketing thereof, thus demonstrating the efficiency of these technologies in disease control and not causing changes in properties of the sleeves / Na pós-colheita, a manga está predisposta a diversas doenças, entre elas o complexo conhecido como podridão peduncular que tem o fungo Lasiodiplodia theobromae como um dos principais agentes, além da podridão por fusicoccum (Fusicoccum parvum) e a antracnose causada por Colletotrichum gloeosporioides. A mangicultura é de grande importância econômica para o Brasil, mas vem perdendo espaço com as perdas que acontecem na pós-colheita, principalmente pela incidência de doenças durante o transporte e armazenamento, havendo necessidade de desenvolver tecnologias que demonstrem eficiência em retardar a senescência das frutas, melhorando a capacidade de comercialização. Entre as tecnologias destacam-se os métodos físicos como a utilização da radiação gama, o armazenamento refrigerado e o uso da atmosfera modificada. O presente trabalho objetivou avaliar os três métodos de controle físico sobre o desenvolvimento pós-colheita de manga e sobre as características físico-químicas conservadas durante os tratamentos. Para isso, as frutas foram inoculadas com os diferentes firopatógenos, e após 24 horas aplicada a radiação gama nas doses de 0; 0,25; 0,35; 0,45 kGy, tendo como fonte o Cobalto60. As frutas foram embaladas com filme plástico de PVC com 380 mm x 10 microns em bandejas de isopor e mantidas sob refrigeração a 13ºC por 15 dias e após esse período conservadas sob temperatura ambiente, de 25ºC sem o filme plástico. Foi observada uma redução do desenvolvimento da doença para os três fungos avaliados, chegando ao controle total da doença quando avaliado o desenvolvimento da antracnose nas mangas que foram submetidas à dose mais alta de 0,45 kGy. As mangas irradiadas não demonstraram diferenças significativas para alguns dos parâmetros avaliados (ácido ascórbico, acidez titulável total (ATT), pH, sólidos solúveis totais (SST), razão (STT/ATT), firmeza e cor da polpa). As mangas inoculadas como o C. gloeosporioides não apresentaram alterações significativas para as propriedades físico-químicas, exceto manchas nas cascas. As mangas inoculadas com L. theobromae e F. parvum não apresentaram diferenças significativas entre ao tratamentos aplicados que comprometesse a comercialização das mesmas, demonstrando assim a eficiência dessas tecnologias no controle das doenças e não causando alterações das propriedades das mangas.

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