*Calonectria canadiana*, un champignon pathogène connu pour entrainer de la pourriture aux racines et au collet, a causé d'importantes pertes dans les cultures d'épinette de deux pépinières forestières gaspésiennes. Afin de mieux comprendre son infectiosité, un essai basé sur le gène de l'espaceur interne transcrit (*Internal transcribed spacer* (ITS)), qui utilise des amorces couplées à une sonde TaqMan, a été testé et validé pour détecter et quantifier *C. canadiana*. Cet essai a ensuite été utilisé pour analyser des échantillons d'air et d'eau provenant d'échantillonnages hebdomadaires faits durant deux saisons de croissance. L'essai a aussi été utilisé pour montrer que les semis présentant des dommages au collet étaient les semis qui contenaient la plus grande biomasse de champignon et que sur ces semis les aiguilles au collet sont la section qui contient la plus grande biomasse de champignon. Des expériences en serre, qui avaient pour but de tester le rôle des spores et des débris végétaux infectés sur le développement de la maladie sur des semis à différents stades de développement et soumis à différents régimes hydriques, ont aussi été analysées à l'aide de l'essai. Il n'a pas été possible de tirer de conclusions de ces expériences à cause du faible nombre de semis infectés. Des échantillonnages ponctuels de débris végétaux et des planches de bois présentes à la surface du lit de roche qui forme les champs ont été faits. Il a été possible de détecter *C. canadiana*, ce qui laisse croire que la surface des champs pourrait être un vecteur du champignon. Pour nettoyer ces champs, il a été envisagé d'utiliser la solarisation, qui utilise la chaleur, et, pour évaluer l'efficacité d'un traitement à la chaleur, un test de résistance à la chaleur a été fait. Il a été observé que *C. canadiana* est éliminé après 1 h d'exposition à 45°C. / *Calonectria canadiana*, a pathogenic fungus known to cause root and crown rot, caused significant losses in spruce crops in two Gaspé forest nurseries. To better understand its infectivity, an assay based on the internal transcribed spacer (ITS) gene, which uses primers and a probe from TaqMan, was tested and validated to detect and quantify *C. canadiana*. This test was then used to analyze air and water samples from weekly sampling taken over two growing seasons. The test was also used to show that seedlings with crown damage were the seedlings that contained the greatest fungal biomass and that on these seedlings the crown needles are the section that contains the greatest fungal biomass. Greenhouse experiments, which aimed to test the role of spores and infected plant debris on the development of the disease on seedlings at different stages of development and subjected to different water regimes, were also analyzed using the test. It was not possible to draw conclusions from these experiments due to the small number of infected seedlings. Spot sampling of plant debris and wooden planks present on the surface of the rock bed which forms the fields were taken. I was possible to detect *C. canadiana*, which suggests that field surfaces could be a vector of the fungus. To clean these fields, it was considered using solarization, which uses heat, and to evaluate the effectiveness of the heat treatment, a heat resistance test was carried out. It has been observed that *C. canadiana* is eliminated after 1 hour of exposure to 45°C.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2015-11-13T13:42:50Z No. of bitstreams: 1 texto completo.pdf: 6365895 bytes, checksum: c3a568253e1c36eb18787e469b99d699 (MD5) / Made available in DSpace on 2015-11-13T13:42:50Z (GMT). No. of bitstreams: 1 texto completo.pdf: 6365895 bytes, checksum: c3a568253e1c36eb18787e469b99d699 (MD5) Previous issue date: 2013-05-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Espécies do gênero Calonectria (= Cylindrocladium) são importantes patógenos em uma ampla gama de plantas hospedeiras, principalmente em regiões de climas tropical e subtropical. A maioria das doenças causadas por espécies de Calonectria ocorre em plantas das famílias Fabaceae (Acacia spp.), Myrtaceae (Eucalyptus spp.) e Pinaceae (Pinus spp.). Atualmente, 76 espécies de Calonectria são reconhecidas com base, principalmente, em morfologia e inferência filogenética. Estudos filogenéticos com este grupo de fungos foram baseados em sequências do gene β-tubulina (TUB2). Entretanto fragmentos da região gênica calmodulina (CAL) e fator de elongação 1-alpha (TEF-1α) tem apresentado melhor resolução para a identificação de novas espécies em Calonectria. Baseado em análise filogenética de sequências de TEF-1α de 1017 isolados obtidos de amostras de plantas e solo em diferentes regiões do Brasil, demonstrou-se que as espécies de Calonectria estudadas pertencem a seis complexos. Dentre esses, C. pteridis, C. brassicae, C. morganii, C. scoparia e C. naviculata contem espécies novas, sendo que o primeiro (87%) predomina nas plantações de eucalipto no Brasil. De acordo com as análises filogenéticas multigênicas de β-tubulina (TUB), histona H3 (HIS3), calmodulina (CAL) e fator de elongação (TEF-1α) e com características morfológicas foram descritas 28 novas espécies de Calonectria. Além disso, 17 espécies de eucalipto (Eucalyptus e Corymbia) foram avaliadas quanto à resistência à mancha de calonectria. Eucalyptus aglomerata, E. brassiana, E. saligna e E. scias foram as mais resistentes, e as espécies E. tereticornis, E. pilularis, C. maculata, E. grandis, E. dunii e C. citriodora foram as mais suscetíveis. / Species of the genus Calonectria (= Cylindrocladium) are important pathogens in a wide range of host plants, particularly in tropical and subtropical climates. Most of the diseases caused by species of Calonectria are associated mainly with plants of Fabaceae (Acacia spp.), Myrtaceae (Eucalyptus spp.) and Pinaceae (Pinus spp.). Nowadays there are about 76 species of Calonectria that are recognized based mainly on morphology and phylogenetic inference. Taxonomic studies on these fungi have chiefly relied on DNA sequences comparisons of the β- tubulin gene region. However calmodulin (CAL) and translation elongation factor 1- alpha (TEF-1α) gene regions have been shown best resolution for the identification of new species in Calonectria. Based on TEF-1α sequence analysis of 1017 isolates collected from samples of plants and soils in different regions of Brazil, it was demonstrated that Calonectria spp. studied belong to six complexes. Among these C. pteridis, C. brassicae, C. morganii, C. scoparia, and C. naviculata complexes contain 28 new species here described. Calonectria pteridis complex predominates (87%) on eucalypt plantations in Brazil. According to morphological features and multigenic phylogenetic analysis of β-tubulin (TUB2), histone H3 (HIS3), calmodulin (CAL) and the elongation factor (TEF-1α) genes 28 new Calonectria species were described. Moreover, in this study 17 species of eucalypt (Eucalyptus and Corymbia) were evaluated for resistance to calonectria leaf blight (CLB). Eucalyptus aglomerata, E. brassiana, E. saligna, and E. scias were the most resistant and E. tereticornis, E. pilularis, C. maculata, E. grandis, E. dunii, and C. citriodora the most susceptible species.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Thesis--Virginia Polytechnic Institute and State University. / Also available via the Internet.

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-04-19T16:08:03Z No. of bitstreams: 1 TEXTO COMPLETO.pdf: 471113 bytes, checksum: d8b75674f0d6200e43ac4e183c41a2ca (MD5) / Made available in DSpace on 2017-04-19T16:08:03Z (GMT). No. of bitstreams: 1 TEXTO COMPLETO.pdf: 471113 bytes, checksum: d8b75674f0d6200e43ac4e183c41a2ca (MD5) Previous issue date: 2001-12-20 / A propagação vegetativa de eucalipto por meio da técnica de miniestaquia vem sendo amplamente empregada nas principais empresas florestais do país. No entanto, ainda se verifica heterogeneidade quanto ao enraizamento entre os genótipos, principalmente na fase inicial de adaptação dos clones. Deste modo, técnicas alternativas que otimizem o enraizamento de estacas e miniestacas de eucalipto são fundamentais para melhorar a qualidade das mudas e reduzir o custo de produção. Além de potencialmente poderem atuar como promotoras de enraizamento, a utilização de rizobactérias na multiplicação clonal de eucalipto, pode propiciar a obtenção de mudas com maior resistência às doenças associadas a viveiros de propagação. Testaram- se 107 isolados de bactérias, obtidos da rizosfera de mudas de diferentes clones de eucalipto, quanto ao seu potencial como promotores de enraizamento de estacas e miniestacas de Eucalyptus spp. Para tanto, amostras de substrato à base de composto de casca de arroz carbonizada:vermiculita (1:1) foram tratados com 10 ml de uma suspensão de cada isolado (OD 540 = 0,2A)/tubete, correspondendo à cerca de 10 8 ufc/ml. Utilizou-se o delineamento inteiramente casualizado (DIC) com cinco repetições por tratamento, cada uma delas constituídas por 10 estacas. Aos 30 dias, avaliou-se o enraizamento médio (porcentagem média de estacas enraizadas) e o peso médio do sistema radicular seco. Dez isolados destacaram-se como excelentes indutores de enraizamento, propiciando ganhos de até 110% no enraizamento médio e de até 250% no peso de raiz. Esses isolados também foram eficientes no enraizamento de miniestacas, cujos ganhos variaram de acordo com o clone e isolado testados. Também se avaliou o efeito dos 10 isolados como promotores de enraizamento em três diferentes substratos: vermiculita pura; moinha de carvão:composto de casca de eucalipto:vermiculita (5:3:2) e composto de casca de arroz carbonizada:vermiculita (1:1). Não se observou interação isolado-substrato, sendo que o substrato à base de composto de casca de arroz carbonizada foi muito superior, quanto à porcentagem de miniestacas enraizadas e ao peso médio de raiz seca. Mudas com cerca de 80 dias de idade, previamente enraizadas em substrato tratado com as rizobactérias, foram testadas quanto à resistência à ferrugem do eucalipto e à mancha de Cylindrocladium candelabrum, em câmaras de crescimento (22 o C/ fotoperíodo = 12 h). Utilizou- se um DIC com quatro repetições, cada uma com três plantas, para ferrugem, e quatro tratamentos com cinco repetições para Cylindrocladium. Aos 13 dias da inoculação, avaliaram-se o número médio de pústulas/ folha, número de soros/ amostra e o número médio de esporos/ soro. Na avaliação da mancha de Cylindrocladium candelabrum, mediu-se apenas o tamanho da lesão ao oitavo dia após a inoculação, visto a mesma ter sido feita utilizando-se discos de micélio. Dois isolados foram bastante eficientes na redução da severidade da ferrugem, no entanto, o mesmo efeito não foi observado para Cylindrocladium. Com o tratamento das mudas com rizobactérias apenas uma semana antes da inoculação com Puccinia psidii, obteve-se redução na severidade da doença muito menor do que a observada nas mudas enraizadas em substrato tratado com bactérias. Os maiores ganhos obtidos no enraizamento de miniestacas (20-40%) são bem expressivos, visto que a técnica de miniestaquia propiciou um ganho de no máximo 40% de enraizamento em relação à estaquia convencional e, no caso do tratamento com rizobactérias, não seria necessário nenhum ajuste no manejo ou na infra-estrutura dos viveiros. Somando-se a esse ganho direto, pode-se ter um melhor aproveitamento da estrutura física desses viveiros, ao se diminuir o tempo que as miniestacas necessitem permanecer em casa-de-vegetação para um bom enraizamento. Os isolados selecionados foram eficientes em várias condições e em diferentes genótipos o que viabiliza a sua utilização em larga escala. Estudos de formulação ainda são necessários, de preferência empregando-se a própria fração orgânica utilizada no preparo dos substratos de enraizamento como veículo. Além disso, o conhecimento dos mecanismos de atuação podem ajudar a potencializar a promoção de crescimento, otimizando a aplicação prática dos isolados em condições de campo. Abre-se aqui um vasto campo de estudo visando aproveitar ao máximo o potencial de rizobactérias na eucaliptocultura. / The major afforestation companies of this country are increasingly using mini-cutting technique for vegetative propagation of eucalyptus. However, there is high heterogeneity in rooting among the genotypes, especially at the initial clone adaptation phase. Thus, alternative techniques, which can optimize the rooting of the cuttings and the mini-cuttings of eucalyptus, are essential for improving the seedling quality and reducing the production cost. Rhizobacteria potentially can act as rooting promoters for clonal multiplication of eucalyptus, and can also help obtain seedlings with greater resistance to nursery diseases. One hundred and seven bacteria obtained from the rhizosphere of seedlings of different eucalyptus eucalyptus clones, were tested for their potential as rooting- promoters of cuttings and mini-cuttings. Substrate based on the compost of carbonized rice hull: vermiculite (1:1) was treated with 10 ml of the bacterial suspension (OD 540 = 0.2 A=10 8 cfu/ml) / tube of either isolate. Completely randomized block design was used with five replications of 10 cuttings each, and mean rooting percentage dry root weight was determined 30 days after planting. Ten isolates were found to be excellent root inducers, increasing rooting percentage by about 110% and root dry weight by 250% relative to controls. These isolates were also efficient in promoting the rooting of mini- cuttings and the beneficial effect varied among the clones and the isolates. The root inducing effect of these isolates was further tested in three different substrates: pure vermiculite; ground charcoal; eucalyptus bark compost: vermiculite (5:3:2) and compost of carbonized rice hull: vermiculite (1:1). There was no isolate-substrate interaction, but the carbonized rice hull: vermiculite substrate was much superior for improving percentage rooting of mini-cuttings and dry root weight. Eighty days old seedlings previously rooted in the rhizobacteria treated substrate were tested for resistance to rust and leaf spot caused by Cylindrocladium candelabrum, in a growth room (22 o C/ 12 h photoperiod). Completely randomized block design with four replications of three plants each was used for rust, and four treatments with five replications were used for evaluating Cylindrocladium. Mean pustules number /leaf, number of sori/sample and the mean spore number /sorus was determined 13 days after inoculation. C. candelabrum leaf spot was evaluated by measuring mean lesion size eight days after inoculation with a mycelial disc. Two isolates were very efficient in reducing the rust severity, but not Cylindrocladium leaf spot. The disease severity reduction was much less in seedlings treated with the rhizobacteria only week before the inoculation with Puccinia psidii, compared to seedlings rooted in the treated substrate. The maximum benefit in the rooting of mini-cuttings (20 to 40%), is expressive, considering that the mini-cutting technique gave only 40% increase in rooting over traditional cuttings. Use of treatment with rhizobacteria, does not require management adjustment or the infrastructure changes of the nurseries. Adding to this direct advantage, there is better use of the physical space of the nursery, because the time required for mini-cuttings to stay in the greenhouse is drastically reduced. The selected isolates were efficient under different conditions and on different genotypes, which makes its large-scale use possible. Studies on the formulation are necessary, preferentially using the same organic fraction used for preparing the rooting substrate as vehicle. Besides this the knowledge of the mode of mechanism can help optimize growth promotion, by optimizing the application practice of the isolates in field conditions. A wide field of study is opened for using maximally the potential of rhizobacteria in eucalyptus cultivation. / Tese importada do Alexandria

Seed transmission of <i>Cylindrocladium parasiticum</i> was investigated as a possible explanation for the higher-than-expected incidence of Cylindrocladium black rot (CBR) of peanut in fields fumigated with metam sodium. Sixty-three commercial seed lots from Virginia production fields were examined for the presence of seed with speckled testae, a symptom of seed infection by <i>C. parasiticum</i>. Speckled seed was present in conditioned seed lots in 1998, 1999, and 2000 at an average rate of 1%. Soon after pods were harvested, the fungus was recovered from speckled seed at high frequencies. During winter seed storage, pathogen survival remained high in seed stored at -13 and 4 C, but declined in some seed stored at 15 C and ambient temperatures. Speckled and normal seed with and without fungicide treatment was planted in steam-treated soil in the greenhouse and metam-treated field plots in 1999 and 2000. Speckled seed treated with captan + pentachloronitrobenzene (pcnb) + carboxin transmitted the pathogen to emerging plants in the greenhouse and field. Transmission levels depended on the amount of viable inoculum present in seed at the time of planting. In the field, yield losses were significant when 20% or more of the seed planted was speckled. The low incidence of speckled seed in commercial seed lots would not result in a loss of yield for growers, but may contribute to disease spread. Testing of additional seed treatment fungicides indicated that fludioxonil, tebuconazole, and thiram may offer the best protection against disease spread from seed transmission of <i>C. parasiticum</i>. / Master of Science

Air drying of naturally infested soils (0.12 to 0.38% water or about -2,000 bars) resulted in no recovery of Cylindrocladium crotalariae microsclerotia, but rewetting soils to near field capacity for 1 to 4 wk before assay resulted in partial recovery from the air drying-induced decreased germinability. Numbers of germinable C. crotalariae microsclerotia (assayed at 26 C) decreased progressively over 4 wk when naturally infested soils were incubated at 6 C. No germinable microsclerotia were recovered when soils were incubated at -10 C. When soils incubated at -10 C and at 6 C were transferred to 26 C for 4 wk, the low-temperature effect was partially reversed. Incubation of naturally infested soils under field conditions over the winter months (November-February) indicated that a similar low-temperature phenomenon exists in nature. Germinability of axenic, laboratory-grown microsclerotia of C. crotalariae, C. floridanum, and C. scoparium incubated 4 wk at 6 C ranged from 0 to 91.3% (mean = 37.7%) of the initial germinability. Partial recovery of laboratory-grown microsclerotia from the lowtemperature effect, by incubation at 26 C, was demonstrated. Conductivity measurements of solutions bathing microsclerotia incubated at 6 C and 26 C for 4 wk indicated that chilling injury may account, in part, for decreased germinability of microsclerotia. Direct observation of washed conidia of C. scoparium on rewetted, non-sterile soils at 26 C indicated that peak germination (33-58%) occurred after 24 h incubation. Peak germination on continually moist soils was somewhat lower (18-26%) than on rewetted soils. Conidia did not germinate on continually moist soils at 6 C. Conidia germinated at a high level (93-95%) in axenic culture in the absence of exogenous carbon and nitrogen substrates. The inhibition of conidium germination on soils was due, in part, to the presence of fungistatic soil volatiles. Addition of low levels of carbon and nitrogen substrates nullified the inhibitory effect of soil volatiles. Germinability of C. scoparium, C. crotalariae, and C. floridanum conidia in artificially infested soils (assayed on a selective medium at 26 C) decreased progressively during incubation at 26 C from 1 wk to 4 mo. No germinable conidia were recovered after incubation of soils at 6 C for 4 wk. Control of Cylindrocladium root rot of black wainut seedlings with sodium azide at 224 kg/ha applied by the plowdown method was comparable to MC-33 at 504 kg/ha. Sodium azide at 67 kg/ha was only marginally effective in disease control. Reduction of Cylindrocladium microsclerotium populations, qualitatively assayed by the azalea leaftrap method, was found in soil samples from plots fumigated with sodium azide and MC-33. A small-spored Cylindrocladium sp. with clavate to papillate vesicles, identified as C. parvum, was consistently recovered from diseased roots and soil samples from a Virginia forest nursery. Percentage recovery from necrotic roots and soil samples collected from root zones of necrotic black walnut seedlings was appreciably higher for C. parvum than for C. floridanum or C. scoparium. In greenhouse tests, limited pathogenicity of C. parvum on black walnut seedlings was demonstrated. / Ph. D.

The effects of herbicides on axenic growth of Cylindrocladium crotalariae and on the development of CBR in the greenhouse and in the field was studied. In laboratory tests, dinitramine at 1, 5, and 10 ug/ml increased axenic growth of two isolates of C. Crotalariae in herbicide-amended potato-dextrose broth (PDB). Dinoseb and dinoseb + naptalam at the same rates also increased growth, whereas alachlor, benefin, diphenamid, vernolate and 2,4-DB were found to have no consistent effect. Treatment of infested soil with dinitramine at 1, 5, 10, 50, and 100 ug/g soil had no significant effects on populations of C. crotalariae microsclerotia (ms) in a Ruston or a Woodstown loamy fine sand. Dinoseb reduced ms populations significantly (P=0.5) in Woodstown soil at 5, 10, 50, and 100 ug/g soil and in Ruston soil at rates of 50 and 100 ug/g soil. In greenhouse tests, soil treatment with dinitramine at 0.56 kg/ha but not at 0.84 kg/ha increased significantly (P=0.05) the severity of CBR in Ruston and in Woodstown soil. In Ruston soil, dinitramine increased the severity of CBR only at an inoculum density of 5 ms/g soil, but in CBR only at an inoculum density of 5 ms/g soil, but in Woodstown soil, the herbicide resulted in disease increase only at 50 ms/g soil. Additional tests showed that disease severity was increased when peanut seedlings were pretreated with dinitramine and transplanted to herbicide-free infested soil. Dinitramine treatment was postulated to alter growth and development processes in ‘Florigiant’ peanut in a way to result in increased susceptibility to CBR. Dinitramine treatment of soil did not increase disease severity in ‘NC3033’ peanut, a CBR-resistant cultivar. Dinoseb at 1.68 kg/ha increased significantly (P=0.05) the severity of CBR in Woodstown soil, but did not in Ruston soil. Higher rates of dinoseb (3.36 and 6.72 kg/ha) were found to have no effect. Field tests were conducted in microplots (77-cm diameter) to determine the effects of herbicides on CBR. The severity of pod rot caused C. crotalariae was increased significantly (P = 0.05) by pre-plant soil treatment with dinitramine at 0.56 kg/ha, but not at 0.84 kg/ha in 1979. Although not significant (P=0.05), substantial increases in root rot and top symptom severity occurred in 1979 in response to this treatment. Pre-plant soil treatments with dinoseb at 1.68, 3.36, and 6.72 kg/ha did not affect disease development in microplots in 1979. In 1980, dinitramine (0.56 kg/ha) increased the severity of both root and pod rot significantly (P=0.05) in two separate microplot tests. Dinoseb at 1.68, but not at 3.36 or 6.72 kg/ha also increased significantly the severity of CBR in these tests.. Soil assay results indicated that herbicide treatments had no consistent effect on populations of C. crotalariae ms, .Macroposthonia ornatum or Meloidogyne hapla in microplots. These results provide evidence that certain herbicides can affect the development and severity of CBR in peanut. Furthermore, the present study emphasizes that knowledge of the non-target effects of pesticides on the biosphere can be significant and must be considered in tbs development of effective disease control programs. / Ph. D.

Made available in DSpace on 2015-03-26T13:37:41Z (GMT). No. of bitstreams: 1 texto completo.pdf: 330706 bytes, checksum: 9be020e5be4feef0a4967a862388b2b0 (MD5) Previous issue date: 2009-10-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / To base the cultivation of Cylindrocladium pteridis and inoculation of the fungus under controlled conditions, was evaluated in this study sporulation in culture, conidial germination, mycelial growth and defoliation of eucalyptus at different temperatures. In preliminary experiments, we evaluated the effect of light and incubation time on germination of conidia. The presence of continuous light significantly reduced germination, resulting in higher germination of conidia in the dark. In assessing the germination under different incubation periods, it was observed that the germination of C.pteridis is very fast, and obtained 100% conidia germinated after 4 h of incubation. In assessing the germination under different temperatures, the optimum for germination was 25 ° C (84.6%). The mycelial growth also varied with temperature, and the maximum was 25 ° C. Aiming to solve the problem of low production of conidia in vitro were evaluated three methods of sporulation of C. pteridis in culture. We compared three methods, and the method of scraping the aerial mycelium followed by flood water was the most sporulation in media AVDA, MEA, PDA and GAA, after 10 days of incubation. We obtained the greatest number of conidia on PDA, with an average of 14.13 x 104 conidia / mL. With half SNA was no significant difference between the methods studied. Subsequently, to study the effect of temperature on leaf eucalyptus, is inoculated plants were kept in a moist chamber at 18, 26, 28 and 30 º C. After 48 h, were transferred to a greenhouse (25 ± 5 º C). The temperature significantly influenced the leaf classes in the base of the crown 50 days after inoculation, and the highest percentage of defoliation occurred at 26 º C. / A fim de embasar o cultivo de Cylindrocladium pteridis e a inoculação do fungo em condições controladas, avaliou-se neste trabalho a esporulação em cultura, a germinação de conídios, o crescimento micelial e a desfolha causada em eucalipto sob diferentes temperaturas. Em experimentos preliminares, avaliou-se o efeito da luminosidade e o tempo de incubação na germinação de conídios. A presença de luz contínua reduziu significativamente a germinação, obtendo-se maior germinação de conídios no escuro. Ao avaliar a germinação sob diferentes períodos de incubação, observou-se que a germinação de C.pteridis é muito rápida, sendo obtido 100% de conídios germinados após 4 h de incubação. Ao avaliar a germinação sob diferentes temperaturas, o ótimo para germinação foi 25 °C (84,6%). O crescimento micelial também variou com a temperatura, e o máximo foi a 25 ºC. Objetivando-se solucionar o problema da baixa produção de conídios in vitro, avaliaram-se três métodos de esporulação de C. pteridis em cultura. Compararam-se três métodos, e com o método de raspagem do micélio aéreo seguido de inundação em água obteve a maior esporulação do fungo nos meios AVDA, MEA, BDA e GAA, após 10 dias de incubação. Obteve-se a maior produção de conídios em BDA, com média de 14,13 x 104 conídios/mL. Com o meio SNA não houve diferença significativa entre os métodos estudados. Posteriormente, para se estudar o efeito da temperatura na desfolha em eucalipto, inocularam-se plantas que foram mantidas em câmara úmida a 18, 26, 28 e 30 ºC. Após 48 h, foram transferidas para casa de vegetação (25±5 ºC). A temperatura influenciou significativamente a desfolha em ramos da base da copa aos 50 dias após inoculação, e o maior percentual de desfolha ocorreu a 26 ºC.

Thèse (M.Sc.)--Université Laval, 2004. / Bibliogr.: f. 61-87. Publié aussi en version électronique.