Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Thesis (M.Sc.). / Written for the Dept. of Natural Resource Sciences. Title from title page of PDF (viewed 2009/06/29). Includes bibliographical references.

Made available in DSpace on 2016-12-08T16:44:51Z (GMT). No. of bitstreams: 1 PGPV15MA178.pdf: 2032529 bytes, checksum: d36174da2f4f90500f36e5d936e28749 (MD5) Previous issue date: 2015-07-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The production of apples (Malus domestica Borkh) is threatened by various diseases, as well as by quarantine diseases. In 2012, the Ministério da Agricultura, Pecuária e Abastecimento - MAPA confirmed cases of European Canker (Neonectria ditissima) in the southern states of Brazil. The European canker can cause death of seedlings and fruit damage and production losses. This study aimed to characterize the morphological and physiological diversity of isolates associated with the European Canker in the counties of Água Doce/SC and Vacaria/RS in culture media and evaluate the effects of fungicides in apple seedlings inoculated. Four experiments were conducted: (1) Morpho-physiological characterization of isolates and observations of conidia; (2) In vitro fungicides efficiency; (3) Aggressiveness of isolates in fruits; and (4) Efficiency of fungicides, in a controlled environment isolated and mixed field, in inoculated seedlings with the pathogen. The morpho-physiological evaluations were made based on mycelial growth and Mycelial Index Growth Speed (MIGS) in culture media, structure formation, coloration of the colonies and production, type and time of spore germination. For the fungicides effectiveness test, doses in ppm was incorporated into malt agar culture and mycelial growth was evaluated at seven days. The aggressiveness of the isolates was tested in fruits of cvs. Gala and Fuji inoculated in injury. Experiments with fungicides, alone or in mixture, were performed on seedlings cv. Gala three years old, treated, inoculated through injury after 24 hours and incubated for 72 hours in the dark and then planted in pots and in the field. The isolates had higher mycelial growth on the PDA, colonies with diameters of 60 mm, forming groups with an average of 35.56 (G1), 52.71 (G2) and an average of 62.67 mm (G3). The MIGS was greater than 4.0 mm in PDA. The sporulation was more abundant in the media SNAY followed by the PDA and AM and the predominant color mycelium in PDA was beige and central pigmentation of brown colonies with borders in shades of beige. Spores were macro type (63,5x10,1, 62.3 x 10.6 and 59.7 x 10.3 μm in PDA, SN and AM) and micro (35.4 x 4.8, 35,2x5 2 and 34.8 x 5.2 μm in PDA, SN and AM). Germination of conidia was observed from 16 hours in a fungal suspension. The mycelial growth was lower in tebuconazole and methyl thiophanate fungicides in vitro assay to seven days. The isolates were aggressive in cvs. Gala and Fuji. The tebuconazole and methyl thiophanate fungicides used alone reduced the cancer lesions. Fosetyl-Al, methyl thiophanate and potassium phosphite mixture, reduced lesion size and mixing captan, methyl thiophanate and potassium phosphite delayed the early onset of symptoms at 15 days according to the average size of the lesions. The incidence of lesions was above 65% at 45 days after inoculation of the seedlings / A produção de maçãs (Malus domestica Borkh) é ameaçada por várias doenças, bem como pelas doenças quarentenárias. Em 2012, o Ministério da Agricultura, Pecuária e Abastecimento - MAPA confirmou casos de cancro europeu (Neonectria ditissima) nos estados do sul do Brasil. O cancro europeu pode causar a morte de mudas e danos e perdas de produção de frutos. Este trabalho teve como objetivos caracterizar a diversidade morfo-fisiológica de isolados associados ao cancro europeu nos municípios de Água Doce/SC e Vacaria/RS em meios de cultura e avaliar os efeitos de fungicidas em mudas de macieira inoculadas. Quatro experimentos foram realizados: (1) Caracterização morfo-fisiológica dos isolados e observações de conídios; (2) Eficiência de fungicidas in vitro; (3) Agressividade dos isolados em frutos; e (4) Eficiência de fungicidas, isolados em ambiente controlado e em mistura a campo, em mudas inoculadas com o patógeno. As avaliações morfo-fisiológicas foram feitas com base no crescimento micelial e Índice de Velocidade de Crescimento Micelial (IVCM) em meios de cultura, formação de estruturas, coloração das colônias e produção, tipo e tempo de germinação dos conídios. Para ensaio de eficiência dos fungicidas, doses em ppm foram incorporados em meio de cultura ágar malte e o crescimento micelial foi avaliado aos sete dias. A agressividade dos isolados foi testada em frutos das cvs. Gala e Fuji com inoculação em ferimento. Os experimentos com fungicidas, isolados ou em mistura, foram realizados em mudas da cv. Gala de três anos de idade, tratadas, inoculadas através de ferimento após 24 hs e incubadas por 72 hs no escuro e posteriormente plantadas em vasos e a campo. Os isolados tiveram o maior crescimento micelial no meio BDA, com colônias de diâmetro maior de 60 mm, formando-se grupos com médias de 35,56 (G1), 52,71 (G2) e média de 62,67 mm (G3). O IVCM foi maior que 4,0 mm no meio BDA. A esporulação foi mais abundante no meio SNAY seguido do BDA e AM e a coloração micelial predominante no meio BDA foi de tons de bege e pigmentação central das colônias marrom com bordas em tons de bege. Os conídios foram do tipo macro (63,5x10,1, 62,3 x 10,6 e 59,7 x 10,3 μm em BDA, SN e AM) e micro (35,4 x 4,8, 35,2x5,2 e 34,8 x 5,2 μm em BDA, SN e AM). A germinação dos conídios foi verificada a partir de 16 hs em suspensão de conídios. O crescimento micelial foi menor nos fungicidas tebuconazole e tiofanato metílico no ensaio in vitro aos sete dias. Os isolados foram agressivos nas cvs. Gala e Fuji. Os fungicidas tebuconazole e tiofanato metílico utilizados isoladamente reduziram as lesões do cancro. Fosetil-Al, tiofanato metílico e fosfito de potássio em mistura, reduziram o tamanho das lesões e a mistura de captana, tiofanato metílico e fosfito de potássio atrasou o início do aparecimento dos sintomas em 15 dias de acordo com a média do tamanho das lesões. A incidência das lesões foi acima de 65% aos 45 dias após a inoculação das mudas

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.