Mémoire (M.Ress.Renouv.)--Université du Québec à Chicoutim, 2000. / Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Ress.Renouv.)--Université du Québec à Chicoutimi, 2001. / Document électronique également accessible en format PDF. CaQCU

Thèse (M.Ress.Renouv..) -- Université du Québec à Chicoutimi, 2006. / Bibliogr.: f. 40-52. Document électronique également accessible en format PDF. CaQCU

Maîtrise (M.Ress.Renouv.)--Université du Québec à Chicoutimi, 1999. / Document électronique également accessible en format PDF. CaQCU

Future climate changes will alter disturbance regimes worldwide with important implications for many ecological and social systems. In west central British Columbia, Canada, fire and insect disturbances have shaped the historic character of Douglas-fir (Pseudotsuga menziesii var. glauca Beissn. Franco) dominated forests. However, since AD 1900 fire suppression and other forest management practices have led to denser forests and conifer encroachment into grasslands. Considering climate changes in interior British Columbia are expected to result in warmer and drier conditions, understanding the influence of climate on forest disturbances is crucial for land managers tasked with both mitigating the effects of disturbance and promoting resilience in forest ecosystems. This research focused on developing multi-century, annually-resolved records of fire and western spruce budworm outbreaks to evaluate: the historic climate conditions related to these disturbances; the influence of grassland proximity on disturbance-climate relationships; and, whether western spruce budworm outbreaks were related to fire activity. At the landscape scale, a detailed study in the Churn Creek Protected Area revealed spatially variable stand structure and fire-climate relationships at a low elevation forest-grassland ecotone over the interval AD 1600 to 1900. This finding suggests the site was characterized by fires of mixed-severity dominated by frequent, low-severity, fires related to positive antecedent moisture conditions punctuated by widespread fires of moderate to high severity related to intervals of persistent drought. At the regional scale, the influence of interannual climate variability and large-scale patterns of climate variability (e.g. El Nino Southern Oscillation) was evaluated using new and existing records of fire history and multiple climate pattern reconstructions. Regional fire activity was shown to be significantly related to interannual climate variability, and no consistent patterns between regional fire years and the individual phases or phase combinations of large-scale patterns of climate variability were detected. The findings suggest that the spatial expression of large-scale climate patterns translates into weak and undetectable terrestrial effects related to fire activity in this region. The influence of grassland proximity on disturbance history was investigated using site-level and regional tree-ring reconstructions of western spruce budworm outbreaks and fire activity based on four sites adjacent to grasslands and four sites not adjacent to grasslands between AD 1600 and 1900 (fire) and AD 1600 and 2009 (western spruce budworm). Fires affecting grassland proximal sites were more frequent than fires occurring in forests not adjacent to grasslands, and the character of western spruce budworm outbreaks was generally consistent among all sites. Fire activity was related to both warm, dry and cool, wet conditions in the fire year and/or year(s) preceding the fire depending on proximity to grasslands, suggesting climate conditions associated with both fine fuel growth and drying are key determinants for fire activity. The initiation of western spruce budworm outbreaks was significantly related to drought and this relationship was enhanced at sites adjacent to grasslands. At the site-level and regional scale, no consistent association was found between the initiation of western spruce budworm outbreaks and fire years indicating the historic interaction between these disturbances is weak or non-existent. / Graduate

Western spruce budworm (Choristoneura occidentalis (Freeman)) is a native defoliator of the Interior Douglas-fir (Pseudotsuga menziesii var. glauca (Mirb.) Franco) forests of British Columbia, Canada. This thesis used dendrochronology and the software program OUTBREAK to reconstruct a defoliation history of Douglas-fir for nineteen forest sites near Kamloops in central British Columbia. By comparing the radial growth response of non-host ponderosa pine trees to Douglas-fir trees growing in nearby but separate stands, seven western spruce budworm outbreaks were distinguished over the past 300 years. Although there is considerable variation in the timing and duration of these western spruce budworm events at the stand level, synchronous outbreaks have occurred at approximately 43-year intervals. Climate variation appears to have been important to budworm outbreaks in the 20th century. Notable outbreaks tended to occur during years of early springs with average air temperature, following winters with lower than average precipitation. Based on this finding, it is proposed that with high overwintering survival, increased population growth rates, and a longer growing season, the extent of future outbreaks will shift northward and may increase in size.

Western spruce budworm (Choristoneura occidentalis (Freeman)) is a native defoliator of the Interior Douglas-fir (Pseudotsuga menziesii var. glauca (Mirb.) Franco) forests of British Columbia, Canada. This thesis used dendrochronology and the software program OUTBREAK to reconstruct a defoliation history of Douglas-fir for nineteen forest sites near Kamloops in central British Columbia. By comparing the radial growth response of non-host ponderosa pine trees to Douglas-fir trees growing in nearby but separate stands, seven western spruce budworm outbreaks were distinguished over the past 300 years. Although there is considerable variation in the timing and duration of these western spruce budworm events at the stand level, synchronous outbreaks have occurred at approximately 43-year intervals. Climate variation appears to have been important to budworm outbreaks in the 20th century. Notable outbreaks tended to occur during years of early springs with average air temperature, following winters with lower than average precipitation. Based on this finding, it is proposed that with high overwintering survival, increased population growth rates, and a longer growing season, the extent of future outbreaks will shift northward and may increase in size.

Made available in DSpace on 2014-06-11T19:25:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-16Bitstream added on 2014-06-13T20:32:40Z : No. of bitstreams: 1 fraga_df_me_jabo.pdf: 1036947 bytes, checksum: 765bfbd32f9b458cda31ae6bb29934a4 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O conhecimento do comportamento de infestação dos insetos em sistemas agrícolas facilita as amostragens, economiza tempo sem perder a confiabilidade para a tomada de decisões no sistema de manejo de pragas. Assim o objetivo foi estudar a distribuição vertical e temporal de ovos de Alabama argillacea e de Heliothis virescens, e o parasitismo de ovos por Trichogramma pretiosum em cultivares de algodoeiro. O delineamento experimental foi em blocos ao acaso, com cinco tratamentos (cultivares DeltaOPAL, FMX-933, FMT-701, FMX-910 e NuOPAL), com oito repetições. As avaliações foram semanais, a partir da emergência das plantas. Para a distribuição vertical, as plantas foram avaliadas nas partes superior, média e inferior, anotando-se o número de ovos. Os ovos de A. argillacea e de H. virescens foram parasitados por Trichogramma pretiosum. Não houve preferência para oviposição por A. argillacea e por H. virescens durante os estágios fenológicos das plantas, tal como o grau de parasitismo por T. pretiosum também não foi influenciado. Quanto à distribuição vertical dos ovos, o terço superior e o médio das plantas foram os mais preferidos para oviposição por A. argillacea nas cultivares NuOPAL, DeltaOPAL e FMX-910, enquanto que H. virescens preferiu ovipositar no terço superior das plantas. T. pretiosum preferiu ovipositar em ovos de A. argillacea presentes no terço superior e médio das plantas, sendo que ovos de H. virescens presentes no terço superior das plantas foram mais parasitados por T. pretiosum / The knowledge of a pest infestation behavior on agricultural areas help the sampling and reduce time without lose confidence on decisions in integrated pest management. This work aimed to study the vertical and temporal distribution of Alabama argillacea and Heliothis virescens eggs, as well as parasitism of its eggs by Trichogramma pretiosum in cotton cultivars. The experimental design was randomized blocks with five treatments with five treatments (cultivars DeltaOPAL, FMX-933, FMT-701 and FMX-910 and NuOPAL) and with eight replicates. Evaluations were performed weekly since plant emergence. For the vertical distribution, plants were divided into three parts, upper, middle and bottom. The number of eggs present in plants was recorded. A. argillacea and H. virescens eggs were parasitized by Trichogramma pretiosum. There was no preference for oviposition by A. argillacea and H. virescens during the plants phenological stages, as well as T. pretiosum parasitism. Concerning the vertical distribution of eggs, the upper and middle parts of the plants were the most preferred for oviposition by A. argillacea on cultivars NuOPAL, DeltaOPAL and FMX-910, and H. virescens preferred to oviposit in the upper part of the plants. T. pretiosum preferred to oviposit in A. argillacea eggs on the upper and middle parts of the plants, and in H. virescens on the upper part of the plants

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No. of bitstreams: 1 eduardo_wi_dr_jabo.pdf: 2274097 bytes, checksum: 93aec24e46ac9b4cc80b0d41df05e805 (MD5) Previous issue date: 2018-02-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Existem poucos estudos a respeito da utilização de genótipos de soja resistentes no manejo de Heliothis virescens (Fabricius, 1781) (Lepidoptera: Noctuidae) e com o aumento de seu ataque nas últimas safras, eles se tornam necessários. Para isso é primordial a padronização de métodos de pesquisa para obtenção desses genótipos, assim como, estudos sobre os mecanismos de defesas e a indução de resistência dessas plantas frente ao ataque desta praga. Com isso, os objetivos deste trabalho foram avaliar metodologias de pesquisa para testes de resistência nas categorias não preferência para alimentação, não preferência para oviposição e antibiose e classificar os genótipos de soja a H. virescens em níveis de resistência; além de verificar a expressão de resistência induzida sob diferentes níveis de injúrias e tempo após as injúrias e analisar alguns possíveis mecanismos morfológicos e químicos envolvidos com a resistência constitutiva e induzida desses genótipos. Nos experimentos de metodologia de pesquisa para testes de resistência na categoria não preferência para alimentação foi possível observar que a densidade de nove lagartas recém-eclodidas e duas lagartas de seis dias de idade por genótipo e folíolos novos de plantas em estádio vegetativos foram os mais indicados para a realização dos testes de resistência com genótipos. Na categoria não preferência para oviposição, as densidades de casais liberadas por genótipo não influenciaram na diferenciação dos genótipos de soja. A quantidade de ovos por fêmea em densidades de dois casais por genótipo não diferiu das densidades de um e três casais, desta forma a densidade de dois casais foi a selecionada para os testes de resistência na categoria de oviposição com os genótipos; em relação a escolha da estrutura vegetal mais apropriada para avaliação, também não houve diferenciação entre os genótipos resistentes e suscetíveis, optando-se assim, em contar os ovos de todas as estruturas vegetais da planta nos testes posteriores desta categoria; ainda na categoria não preferência para oviposição, o estádio fenológico em que se utilizou a planta também não interferiu na diferenciação dos genótipos, adotando-se assim, utilizar para os testes posteriores plantas em estádio vegetativo pela a rapidez na obtenção e facilidade no manejo das plantas. Nos testes de metodologia de pesquisa na categoria antibiose, determinou-se a utilização da densidade de uma lagarta em recipientes de 150 ml por proporcionar maior diferenciação entre o genótipo resistente do suscetível principalmente na viabilidade de lagartas aos 12 dias e viabilidade larval total; nos testes para determinação da estrutura vegetal, determinou-se utilizar somente os folíolos por diferenciar melhor o genótipo resistente do suscetível nos parâmetros peso de lagartas aos 12 dias, viabilidade larval e peso de pupas. Com base nesses resultados foram realizados os testes de resistência constitutiva de genótipos de soja a H. virescens nas categorias não preferência para alimentação, não preferência para oviposição e antibiose, utilizando densidades de lagartas e casais, tamanho de recipiente, estrutura vegetal e plantas em estádio fenológico determinados anteriormente pelos testes de metodologia de pesquisa. Nos testes na categoria não preferência para alimentação, dentre os 26 materiais avaliados, os genótipos IAC-100, Dowling, UFUS Impacta, UFUS Capim Branco e UFUS Milionária se destacaram como vi resistentes, enquanto os genótipos BR-16, CD-208, UFUS Xavante e M8230RR foram classificados como suscetíveis a H. virescens. Esses genótipos classificados como resistentes e suscetíveis foram submetidos aos testes de resistência constitutiva na categoria não preferência para oviposição e o genótipo UFUS Impacta se destacou por expressar resistência. Na categoria antibiose, os genótipos UFUS Xavante e IAC-100 expressaram resistência a H. virescens e o genótipo CD-208 foi classificado como altamente suscetível. Nos testes indução de resistência para determinar o nível de injúria necessária para que plantas de soja fossem induzidas a expressar resistência contra H. virescens observou que todos os níveis de injúria foram suficientes para essas plantas expressarem resistência a esta praga. Determinou-se ainda que no período de 72 a 144 horas após as plantas serem injuriadas por H. virescens ocorreu a maior expressão de resistência. Para elucidar esses resultados foram realizadas análises morfológicas e químicas nas plantas, sendo possível relacionar a densidade de tricomas com a menor oviposição de H. virescens; as concentrações de fibras e lignina, assim como dos flavonoides rutina e hesperidina com a resistência constitutiva de plantas de soja; além de verificar um aumento dos compostos fenólicos com o passar do tempo após as plantas serem injuriadas. Conclui-se assim que, as densidades de lagartas de H. virescens que melhor diferenciam o genótipo de soja resistente do suscetível são nove e duas, para lagartas recém-eclodidas e de seis dias de idade, respectivamente; os folíolos novos de plantas em estádio vegetativo discriminam melhor o genótipo resistente do suscetível; nos testes de não preferência para oviposição não há diferenciação dos materiais resistentes e suscetíveis nas diferentes densidades de casais, estruturas vegetais e estádios fenológicos; a densidade de uma lagarta de H. virescens e o recipiente de plástico com volume de 150 ml assim como as folhas são melhor discrimina os genótipos de soja resistente do suscetível em teste de resistência da categoria antibiose; os genótipos IAC-100 e UFUS Milionária são altamente resistentes e os genótipos Dowling, UFUS Capim Branco, UFUS Impacta são moderadamente resistentes a H. virescens na categoria não preferência para alimentação; o genótipo UFUS Impacta é resistente a H. virescens na categoria não preferência para oviposição; o genótipo UFUS Xavante é altamente resistente e o genótipo IAC-100 é moderadamente resistente a H. virescens na categoria antibiose; plantas de soja do genótipo 84 Davis expressam resistência induzida a H. virescens depois de sofrerem injúrias de 25, 50 e 75% no trifólio mais velho por essa praga; plantas de soja do genótipo 84 Davis expressam resistência induzida a H. virescens a partir de 36h do ataque desta praga, aumentando a resistência até 200h após do ataque, diminuindo após este período; os tricomas são um dos possíveis mecanismos de defesa relacionados com a oviposição das mariposas e não alimentação em vagens de lagartas jovens; o baixo teor de taninos e compostos fenólicos totais estão relacionados com a preferência das lagartas por grãos em desenvolvimento ao invés de folhas; lagartas recém-eclodidas e com seis dias de idade de H. virescens preferem se alimentar de folhas com menores concentrações de fibras e ligninas; os flavonoides rutina e hesperidina estão relacionados com a resistência da categoria não preferência para alimentação em genótipos IAC-100, Dowling, UFUS Capim Branco, UFUS Impacta e UFUS Milionária por H. virescens. / There are few studies on the use of resistant soybean genotypes in the management of Heliothis virescens (Fabricius, 1781) (Lepidoptera: Noctuidae) and with the increase of their attack in the last few seasons, these study become necessary, being important a standardization of the research methods to obtain these genotypes, as well as, studies on the defense mechanisms and the resistance induction of these plants against the attack of this pest. Thus, the aims of this work were to evaluate research methodologies for resistance tests in the categories, non-preference for feeding, non-preference for oviposition and antibiosis, and to classify the soybean genotypes in resistance levels against H. virescens in these categories; besides verifying the expression of induced resistance under injuries levels and time after the injuries caused by H. virescens, and to analyze some possible morphological and chemical mechanisms involved with the constitutive and induced resistance of these genotypes. In the research methodology experiments for resistance tests in the non-preference for feeding category was possible to observe that the density of nine caterpillars neonates and two caterpillars with six-day old per genotype; new leaf of plants in vegetative stage plants were the most indicated for the performance of resistance tests with genotypes soybean. In the non-preference for oviposition category, the couples densities released per genotype did not influence in the distition of the soybean genotypes; in parallel, the amount of lay eggs per female at densities of two couples per genotype did not differ from the densities of one and three couples, in this way the density of two couples was selected for the resistance tests in the non-preference for oviposition category with the genotypes soybean against H. virescens; in relation to the choice of the most appropriate plant structure for evaluation of the resistance tests, there was also no differentiation between the resistant and susceptible genotypes, thus choosing to count the eggs of all structures of the plant in the later resistance tests of this category; the phenological stage in which the plant was used also did not interfere in the differentiation of the genotypes, using, at the later resistance tests, plants at the vegetative stage by the speed in obtaining and ease in the management of the plants. In turn, in the research methodology tests in the antibiosis category, it was determined the use of the density of a caterpillar per containers of 150 ml, for providing greater differentiation between the resistant genotype of the susceptible, mainly in the larval viability at 12 days and larval viability; in the tests to determine the plant structure more suitable for resistance tests, the leaves alone were choose because in these structures there was a greater differentiation of the resistant genotype than susceptible genotype in the parameters larval weight at 12 days, larval viability and pupal weight. Based on these results, constitutive resistance tests of soybean genotypes to H. virescens were performed in the categories non-preference for feeding, no preference for oviposition and antibiosis, using larvae and couples densities, container size, plant structure and plants in phenological stage determined previously by the research methodology tests. In the tests of the non-preference for feeding category, among the 26 genotypes evaluated, the genotypes IAC-100, Dowling, UFUS Impacta, UFUS Capim Branco and UFUS viii Millionaria were the genotypes most resistant, while genotypes BR-16, CD-208, UFUS Xavante and M8230RR were classified as susceptible to H. virescens. These genotypes classified as resistant and susceptible were submitted to constitutive resistance tests in the non-preference for oviposition category and the UFUS genotype. Impacta was noted for expressing resistance to this pest. In the antibiosis category the UFUS Xavante and IAC-100 genotypes expressed resistance to H. virescens, while the CD-208 genotype was classified as highly susceptible. In the induced resistance tests to determine the level of injury required for soybean plants to be induced to express resistance against H. virescens was observed that all injury levels tested were sufficient for these plants to express resistance to this pest We also determined that in the period of 72 to 144 hours after the plants were be injured by H. virescens was respnsable by greatest expression of resistance against this pest occurred among the times tested. In the attempt to elucidate these results, morphological and chemical analyzes of the plants were carried out, being possible to relate the trichomes density with the lowest oviposition of H. virescens; the concentrations of fiber and lignin, as well as the flavonoids rutin and hesperidin with the constitutive resistance of soybean plants to this pest; in addition, we noticed that there was an increase of the phenolic compounds with the increase of the time after the injuries in plants. It is concluded that the densities of H. virescens caterpillars that best differentiate susceptible and resistant soybean genotype are nine and two neonates and six-day old caterpillars, respectively; new folioles of plants in vegetative stage better discriminate the susceptible and resistant genotype; in the non-preference for oviposition tests there is no differentiation of the resistant and susceptible materials for the different densities of couples, plant structures and phenological stages; the density of a H. virescens caterpillar and the plastic container with a volume of 150 ml as well as the leaves are best discriminated against susceptible soybean genotypes susceptible in antibiosis resistance test; in the non-preference category for feeding the IAC-100 and UFUS Millionaria genotypes are highly resistant and the Dowling, UFUS Capim Branco and UFUS Impacta genotypes are moderately resistant to H. virescens; in the non-preference category for oviposition the genotype UFUS Impacta is resistant to H. virescens; in the antibiosis category the UFUS Xavante genotype is highly resistant and the IAC-100 genotype is moderately resistant to H. virescens; soybean plants of the Davis 84 genotype express induced resistance to H. virescens after suffering 25, 50 and 75% injuries in the older trefoil by this pest; soybean plants of the Davis 84 genotype express induced resistance to H. virescens from 36 hours of the attack of this pest, increasing resistance up to 200 h after the attack, decreasing after this period; trichomes are one of the possible defense mechanisms related to oviposition of moths and not feeding on young caterpillar pods; the low content of tannins and total phenolic compounds are related to the preference of caterpillars for developing grains rather than leaves; Neonates and six-day-old caterpillars of H. virescens prefer to feed on leaves with lower fiber and lignin concentrations; the flavonoids rutin and hesperidin are related to resistance of the non-preference category for feeding in genotypes IAC-100, Dowling, UFUS Capim Branco, UFUS Impacta and UFUS Millionaire by H. virescens. / 2014/08373-3

Orientador: Antonio Carlos Busoli / Banca: Marcos Gino Fernandes / Banca: Nilza Maria Martinelli / Resumo: O conhecimento do comportamento de infestação dos insetos em sistemas agrícolas facilita as amostragens, economiza tempo sem perder a confiabilidade para a tomada de decisões no sistema de manejo de pragas. Assim o objetivo foi estudar a distribuição vertical e temporal de ovos de Alabama argillacea e de Heliothis virescens, e o parasitismo de ovos por Trichogramma pretiosum em cultivares de algodoeiro. O delineamento experimental foi em blocos ao acaso, com cinco tratamentos (cultivares DeltaOPAL, FMX-933, FMT-701, FMX-910 e NuOPAL), com oito repetições. As avaliações foram semanais, a partir da emergência das plantas. Para a distribuição vertical, as plantas foram avaliadas nas partes superior, média e inferior, anotando-se o número de ovos. Os ovos de A. argillacea e de H. virescens foram parasitados por Trichogramma pretiosum. Não houve preferência para oviposição por A. argillacea e por H. virescens durante os estágios fenológicos das plantas, tal como o grau de parasitismo por T. pretiosum também não foi influenciado. Quanto à distribuição vertical dos ovos, o terço superior e o médio das plantas foram os mais preferidos para oviposição por A. argillacea nas cultivares NuOPAL, DeltaOPAL e FMX-910, enquanto que H. virescens preferiu ovipositar no terço superior das plantas. T. pretiosum preferiu ovipositar em ovos de A. argillacea presentes no terço superior e médio das plantas, sendo que ovos de H. virescens presentes no terço superior das plantas foram mais parasitados por T. pretiosum / Abstract: The knowledge of a pest infestation behavior on agricultural areas help the sampling and reduce time without lose confidence on decisions in integrated pest management. This work aimed to study the vertical and temporal distribution of Alabama argillacea and Heliothis virescens eggs, as well as parasitism of its eggs by Trichogramma pretiosum in cotton cultivars. The experimental design was randomized blocks with five treatments with five treatments (cultivars DeltaOPAL, FMX-933, FMT-701 and FMX-910 and NuOPAL) and with eight replicates. Evaluations were performed weekly since plant emergence. For the vertical distribution, plants were divided into three parts, upper, middle and bottom. The number of eggs present in plants was recorded. A. argillacea and H. virescens eggs were parasitized by Trichogramma pretiosum. There was no preference for oviposition by A. argillacea and H. virescens during the plants phenological stages, as well as T. pretiosum parasitism. Concerning the vertical distribution of eggs, the upper and middle parts of the plants were the most preferred for oviposition by A. argillacea on cultivars NuOPAL, DeltaOPAL and FMX-910, and H. virescens preferred to oviposit in the upper part of the plants. T. pretiosum preferred to oviposit in A. argillacea eggs on the upper and middle parts of the plants, and in H. virescens on the upper part of the plants / Mestre