Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1913. / Reprints from Journal of agricultural research. Part 1: vol. IV, no. 2 (15 May 1915), p. 135-168, plates xvi-xxvi -- Part 2: vol. V, no. 1 (4 Oct. 1915), p. 55-57, plates i-ii -- Part 3: vol. IV, no. 4 (15 July 1915), p. 279-291, plates xliv-xlviii. Includes bibliographical references.

Phytophthora parasitica is an important root rot pathogen of American and English boxwood, Buxus sempervirens and B. sempervirens var. suffruticosa, respectively, shrubs used extensively in the landscape in Virginia and North Carolina. Studies were undertaken to screen microorganisms for antagonism to Phytophthora in vitro; test two polymers, carboxymethyl cellulose (CMC) and methylcellulose (MC) for their suitability as carriers, storage media, and carbon substrates; and finally to determine the efficacy of selected antagonist pairs in controlling Phytophthora root rot on containerized American boxwood. On the basis of in vitro inhibition tests, 14 organisms were selected. These included six bacteria, five fungi and three actinomycetes. Populations of conidia-forming fungal isolates increased or remained fairly stable when stored in 0.25% suspensions of CMC and MC, indicating that spores may be a more suitable propagule than mycelial fragments when storing fungal isolates for more than 1 week. No significant or consistent changes in population viability occurred among the actinomycete and bacterial isolates. Carboxymethyl cellulose was a more readily utilizable carbon source than MC as indicated by the smaller specific growth rates of microorganisms in MC. Methylcellulose was not utilized by actinomycete and non-spore-forming fungal isolates. Six of seven antagonist pairs were efficacious in controlling root rot in the greenhouse when suspended in CMC. In general, application of antagonist pairs to boxwoods stimulated growth relative to control plants. The polymers may provide the biocontrol organisms with a protective environment and/or food base for establishment of stable population levels in the infection court, providing protection of the root system when challenged with the pathogen. / M.S.

Licenciatavhandling Uppsala : Sveriges lantbruksuniversitet, 2009. / Härtill 2 uppsatser.

Licenciatavhandling Uppsala : Sveriges lantbruksuniversitet, 2009.

Research objective and experimental tasks. The study was designed to explore the incidence and severity of root and foot rots and ascochyta blight in field pea crops and to identify the measures and practices for the prevention and control of the diseases caused by the pathogens of Ascochyta complex. Experimental tasks: - To identify the susceptibility of various field pea varieties to root and foot rots and ascochyta blight under different agro-ecological conditions. - To establish the effect of meteorological factors on the severity of root and foot rots and ascochyta blight in field pea crops. - To determine the frequency of detection of pathogens of Ascochyta complex on various pea varieties. - To estimate the feasibility of control of the diseases caused by the pathogens of Ascochyta complex using seed treatment and fungicide application. - To assess the impact of seed treatment and fungicide application on field pea productivity and yield components. - To study the possible side-effect of the chemical seed treatment on the microflora of pea rhizosphere and soil. / Tyrimų tikslas ir uždaviniai. Tyrimais siekta ištirti šaknų, pašaknio puvinių ir askochitozės išplitimą bei žalingumą sėjamojo žirnio pasėliuose, nustatyti Ascochyta komplekso patogenų sukeliamų ligų prevencijos ir kontrolės priemones. Tyrimų uždaviniai: - Nustatyti įvairių sėjamojo žirnio veislių jautrumą šaknų, pašaknio puviniams ir askochitozei skirtingomis agroekologinėmis sąlygomis. - Nustatyti meteorologinių faktorių įtaką šaknų, pašaknio puvinių ir askochitozės intensyvumui žirniuose. - Nustatyti Ascochyta komplekso patogenų aptikimo dažnį ant įvairių veislių žirnių. - Įvertinti Ascochyta komplekso patogenų sukeliamų ligų kontrolės galimybę naudojant beicus ir fungicidus. - Įvertinti beicų ir fungicidų įtaką žirnių derlingumui ir derliaus komponentams. - Ištirti galimą cheminių beicų šalutinį poveikį žirnių rizosferos bei dirvožemio mikroflorai.

Cucumber root rot caused by Pythium aphanidermatum can be suppressed by introduced plant growth-promoting rhizobacteria (PGPR). Preliminary experiments clarified that this root disease could be suppressed by strains of Pseudomonas aureofaciens, P. corrugata, and P. fluorescens. To determine whether the mechanism was a systemic resistance induced by PGPR, a split root technique was employed on greenhouse cucumbers grown in soilless substrates. On the split roots, bacteria which were introduced into one side of the root were completely separated from pathogen challenged-inoculated roots-on the other side of the roots. Results from the series of experiments conducted with this design demonstrated that (i) the resistance against root rot induced by PGPR was systemic, (ii) germination of P. aphanidermatum zoospores was reduced in extracts from bacterized roots compared to non-treated control, and (iii) spread of Pythium mycelia was delayed and zoospore germination was inhibited on the distant induced root, compared to the non-bacterized control. Furthermore, enzyme analysis indicated that phenylalanine ammonia lyase, peroxidase and polyphenoloxidase increased on cucumber roots two days after they were bacterized with Pseudomonas strains 13 or 63--28. When the bacterized roots were challenged with P. aphanidermatum, these plant defense enzymes increased as the symptoms appeared, but this accumulation of enzymes was not any higher on roots induced with each of the Pseudomonas strains compared to the Pythium inoculated control. This enzyme stimulation was also systemically induced by PGPR or P. aphanidermatum on cucumber roots. The patterns of iso-peroxidase induced with the PGPR and P. aphanidermatum treatments were different. High levels of salicylic acid (SA) accumulated in bacteria-induced roots, as well as in pathogen-infected roots, which suggests that SA may be associated with cucumber resistance response. But exogenous application of SA did not induce any systemi

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2008. / Härtill 4 uppsatser.

The papaya culture is extensively cultivated in the world, where Brazil meets as worldwide the producing greater. Amongst the problems main inherent to the culture, the root and fruit rots are distinguished, caused by Phytophthora palmivora. The present work had for objective to control P. palmivora in seedling of papaya cv. Sunrise solo, through methods of biological, physical and chemical control. They had been tested four Trichoderma isolated (T. koningii - T3; T. harzianum - T13; Trichoderma sp. - T152D and T. polysporum - TP) and five fungicides "in vitro" (copper oxychloride - 2; 3 e 4g/L; mancozeb - 2; 3 e 4g/L; metalaxyl + mancozeb - 2,5; 3,5 e 4g/L; thiophanate-methyl - 6; 7 e 8g/L and carbendazim - 0,5; 1,0 e 1,5mL/L) and "in vivo", as well as the solarization of the substratum in solar collectors. They had been made still, test of volatile, not volatile metabolites and hyperparasitism for the Trichoderma isolated. In the biological control "in vitro", used the plate technique, while in the in vivo control, the substratum was dealt with Trichoderma of isolated and integrated form, before the infestation of the ground. In the chemical control, the fungicides had been tested "in vitro" adding them in BDA medium, while "in vivo" the seedlings roots had been immersed during 10 minutes in the fungicides solution. The solarization of the substratum was carried during 24, 48 and 72 hours, in solar collectors of 10 and 15 cm of diameter, becoming infested itself, previously the substratum with the pathogen (40 mL of inocule with approximately 20 sporangia for mL/ vase). The Trichoderma isolated T3, T13 and TP had been most efficient in the inhibition of the growth of P. palmivora "in vitro", however, only the isolated TP produced volatile and not volatile metabolites. On the other hand, all the isolated ones had presented capacity to hyperparasite the pathogen. In the biological control "in vivo" no isolated one was capable to reduce the severity of the disease. The solarization of the substratum increased significantly the seedlings survival, when compared to the witness. It didn t have significant differences between the periods of solar exposition, however, the diameter of 15 cm presented one better efficiency, with 87% of seedlings survival. The products most efficient in the pathogen inhibition "in vitro" had been oxicloreto de cobre, mancozeb and metalaxyl + mancozeb, while "in vivo" the five fungicides had presented similar efficiency, not having significant difference between the dosages tested. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A cultura do mamoeiro é extensamente cultivada no mundo tendo o Brasil como o maior produtor. Dentre os principais problemas inerentes à cultura, destacam-se as podridões do pé e do fruto, causadas por Phytophthora palmivora. O presente trabalho teve por objetivo avaliar o controle de P. palmivora em plântulas de mamoeiro cv. Sunrise solo, utilizando métodos de controle biológico, físico e químico. Foram testados quatro isolados de Trichoderma (T. koningii - T3; T. harzianum - T13; Trichoderma sp. - T152D e T. polysporum - TP) e cinco fungicidas in vitro (oxicloreto de cobre - 2; 3 e 4g/L; mancozeb 2; 3 e 4g/L; metalaxyl + mancozeb 2,5; 3,5 e 4g/L; tiofanato metílico 6; 7 e 8g/L; e carbendazim 0,5; 1,0 e 1,5mL/L) e in vivo na dosagem recomendada pelo fabricante, bem como a solarização do substrato em coletores solares. Foram feitos ainda, testes de metabólitos voláteis, não voláteis e hiperparasitismo para os isolados de Trichoderma. No controle biológico in vitro , utilizou-se a técnica de confrontamento em cultivo pareado, enquanto no controle in vivo , o substrato foi tratado com os isolados de Trichoderma de forma isolada e integrada, antes da infestação do solo com o patógeno. No controle químico, os fungicidas foram testados in vitro adicionando-os ao meio BDA, enquanto in vivo as raízes das plântulas foram imersas durante 10 minutos na solução dos fungicidas. A solarização do substrato foi realizada durante 24, 48 e 72 horas, em coletores solares de 10 e 15 cm de diâmetro, infestando-se, previamente o substrato com o patógeno (40 mL do inoculo com aproximadamente 20 esporângios por mL / vaso). Os isolados de Trichoderma T3, T13 e TP foram os mais eficientes na inibição do crescimento de P. palmivora in vitro , no entanto, apenas o isolado TP produziu metabólitos voláteis e não voláteis. Por outro lado, todos os isolados apresentaram capacidade de hiperparasitar o patógeno. Já no controle biológico in vivo nenhum isolado foi capaz de reduzir a severidade da doença. A solarização do substrato aumentou significativamente a sobrevivência das plântulas quando comparada à testemunha. Não houve diferenças significativas entre os períodos de exposição solar, entretanto, o diâmetro de 15 cm apresentou uma melhor eficiência, com 87% de sobrevivência das plântulas. Os produtos mais eficientes na inibição do patógeno in vitro foram oxicloreto de cobre, mancozeb e metalaxyl + mancozeb, enquanto in vivo os cinco fungicidas apresentaram eficiência semelhante, não havendo diferença significativa entre as dosagens testadas.

Made available in DSpace on 2014-06-11T19:28:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-25Bitstream added on 2014-06-13T18:57:48Z : No. of bitstreams: 1 santos_lo_me_jabo.pdf: 780193 bytes, checksum: cc0c763c9b87f0bcd74b72f3de8c1fe3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho objetivou testar o uso de tratamento químico combinado ou não com tratamento hidrotérmico, na conservação e qualidade pós-colheita de mangas ‘Tommy Atkins’ e ‘Palmer’, bem como avaliar o efeito da modificação da atmosfera de armazenamento por filmes plásticos e cera de carnaúba no prolongamento da vida útil pós-colheita de mangas ‘Palmer’. Utilizou-se mangas provenientes de pomar comercial de Taquaritinga-SP, safra 2006/2007, que foram colhidas no estádio de maturação “de vez” e imediatamente transportados para o laboratório de Tecnologia dos Produtos Agrícolas da FCAV, Jaboticabal, onde foram selecionadas, visando padronizá-las quanto a coloração, tamanho e ausência de injúrias. Na primeira fase os frutos foram submetidos a tratamento com os fungicidas Sporekill® (cloreto de dodecil dimetil amônio a 12%) e Magnate 500 EC® (imazalil a 50%), associados ou não com tratamento hidrotérmico a 53°C/5 min (‘Tommy Atkins’) e 53°C/10 min (‘Palmer’). Após secagem, eles foram armazenados sob condição de ambiente (23°C, 65% UR), e eram analisados a cada três (‘Palmer’) ou quatro dias (‘Tommy Atkins’), quanto a ocorrência de podridões, aparência, perda de massa e firmeza, assim como quanto ao pH e teores de sólidos solúveis, acidez titulável e ácido ascórbico da polpa. Na segunda fase, o melhor tratamento para a manga ‘Palmer’ foi combinado com diferentes proteções e armazenamento sob condição ambiente (23°C, 65% UR) ou refrigerada (12°C, 65% UR). Os frutos armazenados sob refrigeração, após 28 dias foram levados ao ambiente, para avaliação da evolução do amadurecimento, aos 3 e 6 dias. Utilizou-se os seguintes tratamentos: Testemunha (sem tratamento); Testemunha com tratamento fitossanitário; Filme de polietileno de baixa densidade (PEBD), com espessura de 0,050mm; Polifilme multicamada;... / This work was undertaken to test the use of chemical control in combination or not with hydrothermal treatment on the preservation and post harvest quality of ‘Tommy Atkins’ and ‘Palmer’ mangoes. Also, we evaluated the effect of modifying the storage atmosphere by the use of plastic film and carnauba wax on the shelf life of ‘Palmer’ fruits. Mangoes from a commercial orchard in Taquaritinga-SP were harvested in the season 2006/2007 at the breaker ripening stage, immediately transported to the laboratory of Technology of Agricultural Products, FCAV, Jaboticabal, and selected by color, size and absence of injuries. In the first stage, fruit were treated with the fungicides Sporekill® (12% dodecyl dimethyl ammonium) and Magnate 500 EC® (50% imazalil), associated or not with hydrothermal treatment at 53°C for 5 min (‘Tommy Atkins’) and 53°C for 10 min (‘Palmer’). After drying, fruits were stored at room temperature (23°C, 65% RH), and analyzed every three (‘Palmer’) or four days (‘Tommy Atkins’) for the occurrence of rots, appearance, weight loss and firmness, as well as pH and the levels of soluble solids, titable acidity and ascorbic acid in the pulp. In the second phase, the best treatment for ‘Palmer’ mangoes was combined with different protections and storage at room conditions (23°C, 65% RH) or refrigerated (12°C, 65% RH). Fruits stored with refrigeration were transferred to room conditions after 28 days for ripening evaluations 3 and 6 days later. The following treatments were used: untreated control, fungicide-treated control, low-density polyethylene film (0.050mm), multilayer polyfilm, polyvinyl chloride (PVC) film (0.017mm), and 18% carnauba wax. In the first stage, fruits from the cultivars Palmer and Tommy Atkins submitted to different treatments showed no wilting symptoms until the sixth and eighth day, respectively ...(Complete abstract

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