Large stands of Arundinaria gigantea (Walt.) Muhl., called canebrakes, were vital to wildlife and lowland ecosystem functions and historically covered millions of acres in the southeastern United States. Since European settlement, human disturbance (i.e, clearing for agriculture and fire suppression) has caused giant canebrakes to become critically endangered ecosystems. Increasing evidence suggests the loss of canebrakes has directly impacted riparian ecosystems, resulting in increased soil erosion, poorer water quality, and reduced flood control. Cane's ecological importance has led to an increased interest in canebrake restoration in riparian zones. To examine the role that cane plays in nutrient cycling and to attempt to determine targeted restoration sites, a four phase research strategy was designed to determine physical and chemical properties of existing riparian stands of native giant cane and their associated soils. Phase one was a GIS analysis to determine what geographical features may be used in selecting sites within a landscape suitable for canebrake restoration. First, common physical site characteristics for 140 existing southern Illinois canebrakes were determined. Soil taxonomy and pH were used to represent soil characteristics and percent slope was used as a topographic metric. These factors, combined with digital elevation models and land cover in GIS were used to identify the potential suitability of sites within the watershed for canebrake plantings and general riparian restoration. The following soil characteristics were determined to be associated with giant cane success: percentage of area containing slopes of 3 percent or less, fine to coarse-silty textures, pH of 5.3 - 6.7, effective cation exchange capacity of less than 30 units, available water holding capacity greater than 0.12, bulk density of 1.37 - 1.65 g cm-3, and percent clay of 11 - 55. Eighty-percent of existing giant cane sites were found within these slope and soil characteristics. The total area of potential riparian canebrake landscapes based on these parameters is 13,970 hectares (35,600 acres) within the Cache River watershed. The remaining three phases examined the role that cane plays in nutrient cycling. Phase two determined the pools and cycling of nitrogen and carbon in canebrakes and compared those to nearby agricultural and forested riparian areas. Phase three quantified the N2O and CO2 fluxes from canebrakes and adjacent forested areas. Phase four included methods to quantify nutrient content of leaf litter and live leaves from existing canebrakes to estimate the nutrient use efficiency of cane. Further, a decomposition study was conducted to calculate the decomposition rate of cane leaves and to explore the litter quality attributes of giant cane. The primary purpose of phase two was to compare the effects of perennial riparian vegetation (giant cane and forest) and annual crops on soil quality, nitrogen cycling, and physical properties. This was to determine if any of them have a significant influence on giant cane distribution, while focusing on nitrogen dynamics to help determine why giant cane is a successful riparian buffer species. Five study sites in the Cache River watershed that had cane, agricultural fields (corn-soybean rotation), and forested areas adjacent to one another were selected. Data were collected on soil texture, carbon/nitrogen ratios, bulk density, nitrogen content (as ammonia and nitrate), and net nitrogen mineralization rates. The crop sites had significantly lower soil C:N ratios than both forest and cane (9.8:1 vs. 10.9:1 and 10.7:1, respectively), though all sites had ratios less than 25:1, indicating a tendency toward nitrogen mineralization. Forest soils had significantly higher rates of net mineralization than cane (19.0 μg m-2 day-1 and 6.6 μg m-2 day-1, respectively), with crop not significantly different from either cane or forest (8.0 μg m-2 day-1). Cane had higher levels of soil carbon and nitrogen when compared to forest and crop soils. Cane can be successful in wetter areas than previously thought, implying that the range of conditions that will support cane is broader than previously thought. Overall, there were few identifiable soil controls on giant cane distribution, or those that differentiate long-standing canebrakes from the nearby crop and forest land. For Phase three, nitrous oxide and carbon dioxide emissions were measured monthly for one year in riparian canebrakes and forests in southern Illinois to determine the rates of greenhouse gas (GHG) fluxes in bottomland riparian areas. Carbon dioxide emissions had a strong correlation with soil temperature (p < 0.001, r2= 0.54), but not with soil water content (p > 0.05), and were greater during the warmer months. Nitrous oxide emissions had a correlation with soil water content (p=0.470, r2 = 0.11), but no relation with soil temperature (p > 0.05), nor a difference across time. Vegetation type did not appear to influence GHG fluxes. Riparian CO2 and N2O emission rates were higher than documented cropland emissions, indicating riparian restoration projects to reduce NO3 delivery to streams may affect N2O and CO2 emissions resulting in an ecosystem tradeoff between water quality and air quality. Leaf deposition, N resorption efficiency and proficiency, and decomposition rates were analyzed in riparian stands of Arundinaria gigantea in southern Illinois for the first time in Phase four. Leaf litter was collected from five established canebrakes monthly over one year and a decomposition study was conducted over 72 weeks. Live leaves, freshly senesced leaves, and decomposed leaves were analyzed for carbon and nitrogen content. Leaf litterfall biomass peaked in November at twice the monthly average for all but one site, indicating a resemblance to deciduous leaf fall patterns. Nitrogen and carbon levels decreased 48% and 30%, respectively, between live leaves and 72 weeks decomposed. High soil moisture appeared to slow decomposition rates, perhaps due to the creation of anaerobic conditions. Cane leaves have low resorption proficiency and nutrient use proficiency, suggesting that these riparian canebrakes are not nitrogen limited. These results will help improve our understanding of the role that giant cane plays in a riparian ecosystem and help focus cane restoration efforts in southern Illinois.

Cercospora sojina, the causal agent of frogeye leaf spot, is an important pathogen of soybean that reduces soybean yield by an average of 9.1 million bushels each year in the United States. Management strategies include using resistant cultivars and fungicide applications. Hill plots were used to evaluate over 600 commercial and public varieties for resistance or susceptibility to C. sojina. Each hill plot was spaced 0.6 m apart, planted with 10 seeds from a single cultivar, and was replicated three times. At flowering, the plants were inoculated by spraying a spore solution across all plants in the field. Hill plots were rated for disease severity at 14, 28 and 35 days after inoculation. There were 259 varieties that were susceptible to FLS, with 181 varieties with intermediate resistance, and 161 resistant varieties. A greenhouse trial evaluated fungicides and their ability to hinder symptom production and the duration of this suppression. Spores of the pathogen were applied at 7, 14 and 21 days after application of fungicides. Disease ratings were collected at 5 weekly intervals following inoculation. The significantly different treatment with the lowest disease ratings was the fungicide Stratego YLD (a strobilurin and triazole mix). The fungicide Tilt was found to be significantly different from all other treatments in the number of lesions on a single tracked leaf, including the non-treated control. These results can be used to recommend to producers available varieties.

The increasing interest of modeling global carbon cycling during the past two decades has driven this research to map leaf area index (LAI) at multiple spatial resolutions by combining LAI field observations with various sensor images at local, regional, and global scale. This is due to its important role in process based models that are used to predict carbon sequestration of terrestrial ecosystems. Although a substantial research has been conducted, there are still many challenges in this area. One of the challenges is that various images with spatial resolutions varying from few meters to several hundred meters and even to 1 km have been used. However, a method that can be used to collect LAI field measurements and further conduct multiple spatial resolution mapping and accuracy assessment of LAI is not available. In this study, a pilot study in a complex landscape located in the Southern Illinois was carried out to map LAI by combining field observations and remotely sensed images. Multi-scale mapping and accuracy assessment of LAI using aerial photo, Landsat TM and MODIS images were explored by developing a multi-scale sampling design. The results showed that the sampling design could be used to collect LAI observations to create LAI products at various spatial resolutions and further conduct accuracy assessment. It was also found that the TM derived LAI maps at the original and aggregated spatial resolutions successfully characterized the heterogeneous landscape and captured the spatial variability of LAI and were more accurate than those from the aerial photo and MODIS. The aerial photo derived models led to not only over- and under-estimation, but also pixilated maps of LAI. The MODIS derived LAI maps had an acceptable accuracy at various spatial resolutions and are applicable to mapping LAI at regional and global scale. Thus, this study overcame some of the significant gaps in this field.

BARROS, Ileane Oliveira. Anatomia ecológica foliar de espécies da caatinga. 2010. 70 f. Dissertação (Mestrado em ecologia e recursos naturais)- Universidade Federal do Ceará, Fortaleza-CE, 2010. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-05-20T17:51:26Z No. of bitstreams: 1 2010_dis_iobarros.pdf: 14293895 bytes, checksum: 6e22eb1d62c6976a3e75933ef5769b61 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-05-27T20:14:53Z (GMT) No. of bitstreams: 1 2010_dis_iobarros.pdf: 14293895 bytes, checksum: 6e22eb1d62c6976a3e75933ef5769b61 (MD5) / Made available in DSpace on 2016-05-27T20:14:53Z (GMT). No. of bitstreams: 1 2010_dis_iobarros.pdf: 14293895 bytes, checksum: 6e22eb1d62c6976a3e75933ef5769b61 (MD5) Previous issue date: 2010 / In semiarid environments water availability is a main limiting factor for plants. A combination of characteristics can contribute to saving water, including the anatomical ones. The anatomical attributes often associated with environments of water restriction are called xeromorphic. The leaves are organs commonly exposed to sunlight which have large areas of transpiration. It is assumed that the leaves of species in the caatinga exhibit some morphological and anatomical attributes that enable them to withstand the conditions of semiarid environment in which they live. Thus, we performed anatomical collection and processing according to standard techniques in thirteen leaves of species common in the caatinga. Xeromorphic characteristics observed are possibly related to water economy. Three functional groups were distinguished with respect to such attributes. The first (G1), consists of deciduous species with dense indument. The second (G2), consists mainly deciduous, and a distinctive feature is mucilage in the epidermal cells. In the third (G3) are two deciduous and three evergreen with tougher leaves and thick cuticle. These groups have phylogenetic influence, though some close relationships can not be attributed just to kinship, indicating other similarities, probably functional, with respect to the use of the main limiting factor in semiarid environments: water. The various ways of exploiting the same resource suggest niche differentiation, resulting in the different groups, while sharing characteristics may reflect the limited number of adaptive solutions that direct possible convergences responsible for characteristics shared within a group phylogenetically distant. / Em ambientes semiáridos a disponibilidade hídrica é o principal fator limitante para as espécies vegetais. Uma associação de características pode contribuir para a economia hídrica, entre elas as anatômicas. Os atributos anatômicos frequentemente relacionados com ambientes de restrição hídrica são denominados xeromorfos. As folhas são órgãos comumente expostos à incidência solar que apresentam grandes áreas de transpiração. Presume-se que as folhas das espécies da caatinga apresentem atributos morfológicos e anatômicos que lhes permitam suportar as condições de semiaridez do ambiente em que vivem. Desta maneira, foi realizada a coleta e processamento anatômico de acordo com técnicas usuais de folhas em treze espécies comuns na caatinga. As características xeromorfas observadas são possivelmente relacionadas com a economia hídrica. Foram distinguidos três grupos funcionais com relação a tais atributos. O primeiro (G1) composto por espécies caducifólias tardias com indumento denso. O segundo (G2) agrupa principalmente as caducifólias, e um elemento marcante foi a presença de mucilagem nas células epidérmicas. No terceiro (G3) estão as perenifólias e duas caducifólias tardias com folhas mais resistentes e cutícula espessa. Estes agrupamentos tiveram influência filogenética, entretanto algumas relações de proximidade não podem ser atribuídas unicamente ao parentesco. Isso pode indicar outras similaridades, provavelmente funcionais, com relação ao uso do principal fator limitante do semiárido nordestino: a água. As diversas maneiras de explorar um mesmo recurso sugerem diferenciação de nicho que origina os diferentes grupos, enquanto o compartilhamento de características pode refletir o número limitado de soluções adaptativas que direcionariam possíveis convergências responsáveis pelas características compartilhadas dentro de um grupo filogeneticamente distante.

Iridaceae é uma das maiores famílias de monocotiledôneas, apresentando cerca de 66 gêneros e 2.000 espécies. Sisyrinchium é o segundo maior gênero da família e o primeiro em número de espécies das Américas, com cerca de 140 espécies. Entretanto, apresenta problemas de delimitação de espécies e, muitas vezes, é de confusa identificação. O objetivo deste estudo é contribuir para a elucidação de problemas taxonômicos nas espécies de Sisyrinchium sec. Hydastylus sensu Ravenna, reconhecendo e caracterizando táxons ocorrentes na Região Sul do Brasil. Esse trabalho apresenta uma revisão bibliográfica das espécies da seção Hydastylus, com pequenas descrições e desenhos que ajudam na identificação das espécies de Sisyrinchium pertencentes a essa seção; caracteres de anatomia foliar que possam auxiliar na delimitação dessas espécies; e a descrição de duas espécies novas de Sisyrinchium ocorrentes na Região Sul do Brasil: Sisyrinchium antemeridianum Aita & L.Eggers e Sisyrinchium flabellatum Aita & L.Eggers. / Iridaceae is one of the largest families of monocots, with about 66 genera and 2,000 species. Sisyrinchium is the second largest genus in the family and the one with the most number of species in the Americas, with about 140 species. However, it presents problems with species delimitation and it is often of confusing identification. The aim of this study is to contribute to the elucidation of taxonomic problems in species of Sisyrinchium sec. Hydastylus sensu Ravenna, recognizing and characterizing taxa occurring in Southern Brazil. This work presents a bibliographic review of the species of section Hydastylus, with short descriptions and drawings that help to identify the species of Sisyrinchium belonging to this section; characters of leaf anatomy that can help the species delimitation, and the description of two new species of Sisyrinchium occurring in Southern Brazil: Sisyrinchium antemeridianum Aita & L.Eggers and Sisyrinchium flabellatum Aita & L.Eggers.

O Brasil precisa se inserir no mercado de carne ovina. Para que isso ocorra, são necessárias mudanças comportamentais dentro dos sistemas produtivos e de todos os agentes envolvidos com a atividade. A produção de carne de cordeiro de qualidade no outono é extremante importante para a regularização da oferta e consolidação da cadeia produtiva. Surge assim a necessidade de avaliação de sistemas de alimentação de cordeiro para abate no outono, aproveitando o grande potencial das pastagens de verão no Brasil. Esse trabalho objetivou avaliar os reflexos da suplementação de cordeiros no desempenho animal e na pastagem, para abate no outono. Utilizou-se 54 animais Texel e Corriedale, seis animais por piquete com área de 0,1 ha cada. Os tratamentos foram: somente capim Aruana; capim Aruana mais suplementação com 1,5% e 2,5% do peso vivo com ração (PV). Foi disponibilizado, para todos os animais, a oferta de 4% do PV de matéria seca de folha verde (MVL). Foi realizada a avaliação quantitativa e qualitativa da pastagem. Avaliou-se os cordeiros quanto ao ganho médio diário de peso (GMD), ganho por hectare (G ha-1), escore da condição corporal (ECC) e realizado a avaliação do comportamento ingestivo. O delineamento foi em 3 blocos casualizados, 3 tratamentos e 3 repetições. Houve diferença significativa entre os tratamentos para ganho médio diário por hectare (P=0.0174), mas não houve efeito de período. O maior ganho foi no tratamento com 2.5% do PV de suplementação, e o menor com os animais não suplementados. Para a variável altura do pasto, a interação entre tratamento e período foi significativa (P=0.0373). Notou-se uma pastagem mais baixa quando os cordeiros não foram suplementados. O aumento da carga animal ao ser fornecido 1.5% do peso vivo com concentrado não foi suficiente para mostrar uma diferença significativa com o tratamento sem suplementação. Os resultados mostram o potencial aumento da produção e produtividade com uso de 2.5% do peso vivo (PV) com concentrado, mas com limitada resposta quando a suplementação é de apenas 1.5% PV em pastagens tropicais. Apesar do aumento produtivo, a suplementação com concentrado proporcionou um forte impacto negativo na estrutura da pastagem e no comportamento dos animais que deve ser considerada quando for utilizado suplementação com concentrado na terminação de cordeiros em regiões tropicais. / Brazil needs to insert the sheep meat market. For this to occur, behavioral changes within the production systems and all those involved with the activity are needed. The production of lamb meat quality in autumn it is extremely important for the regulation of supply and consolidation of the supply chain. Thus arises the need to review the supply of lamb for slaughter in the fall systems, taking advantage of the great potential of summer pastures in Brazil. This study aimed to evaluate the effects of the supplementation of lambs on animal performance and pasture to slaughter in the fall. It was used 54 animals Texel and Corriedale, six animals per paddock with 0.1 ha each. The treatments were: Aruana only grass; Aruana more grass supplementation with 1.5% and 2.5% of body weight with diet. Was available to all animals, the offer of 4% body weight dry matter of green leaf. Quantitative and qualitative evaluation of pasture was held. Was evaluated the lambs as the average daily gain, gain per hectare (L ha-1), body condition score and performed the evaluation of feeding behavior. The design was a randomized block 3, 3 treatments and 3 replications. There were significant differences among treatments for average daily gain per hectare (P = 0.0174), but there was no period effect. The largest gain was in treatment with 2.5% body weight supplementation, and the lowest with non-supplemented animals. For the variable height of the grass, the interaction between treatment and period was significant (P = 0.0373). It was noted a lower pasture where the lambs were not supplemented. Increasing stocking rate to be supplied 1.5% of body weight concentrate was not enough to show a significant difference from treatment without supplementation. The results show the potential increase in production and productivity with the use of 2.5% of body weight with concentrated, but with limited response when supplementation is only 1.5% body weight in tropical pastures. Despite the increase in production, supplementation with concentrate provided a strong negative impact on pasture structure and behavior of animals that should be considered when used concentrate supplementation in lamb finishing in tropical regions.

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-09-24Bitstream added on 2014-06-13T21:06:46Z : No. of bitstreams: 1 carvalho_ems_dr_jabo.pdf: 998912 bytes, checksum: fca2c550ea3f00d2dbfbc2f1213a506f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A antracnose é freqüentemente encontrada em feijão-fava na região nordeste do Brasil, porém é pouco estudada. Nesse sentido, objetivou-se caracterizar o agente causal da antracnose, determinar a reação de genótipos a Colletotrichum truncatum e investigar a viabilidade da utilização da técnica de folhas destacadas em estudos relacionados a essa doença. Isolados foram caracterizados em relação a aspectos morfoculturais quando cultivados em meios de cultura batata-dextrose-ágar (BDA) e feijão-dextrose-ágar (FDA), em temperaturas de 26, 28 e 30ºC e fotoperíodo de 12 horas. A patogenicidade dos isolados e a reação dos genótipos foram avaliadas em folhas destacadas e na planta. O comportamento dos genótipos foi avaliado em duas épocas, no período chuvoso (17 de abril a 02 de junho/2008) e período seco (13 de junho a 29 de julho/2008). O delineamento utilizado foi o inteiramente casualizado com cinco e quatro repetições para avaliação da patogenicidade e dos genótipos, respectivamente. As características morfológicas e culturais variaram de acordo com o isolado e condições de cultivo, porém, foram compatíveis com as descritas para a espécie C. truncatum. A patogenicidade foi comprovada, porém não foram detectadas diferenças significativas entre os isolados. Os primeiros sintomas da doença apareceram aos três dias após a inoculação em folhas destacadas e plantas. Os genótipos UFPI - 578, UFPI - 468 e UFPI - 26 foram suscetíveis a C. truncatum. Quando avaliados em folha destacada não diferiram estatisticamente entre si no nível de infecção, independente da época. Em planta e na ausência de chuva, UFPI - 26 apresentou o maior nível de infecção, enquanto UFPI - 578, o menor. A correlação positiva e significativa (P<0,0001) entre folha destacada e planta comprova a viabilidade do emprego da técnica de folhas destacadas em estudos relacionados a essa doença / Anthracnose is often found in lima bean plantations in the northeast region of Brazil, however, has been little studied. In this sense, the goals were to characterize the causal agent of anthracnose, determine the reaction of genotypes to Colletotrichum truncatum and investigate the viability of using the technique of detached leaves in studies related to this disease. Isolates were characterized in relation to aspects morphocultural when grown in culture BDA and FDA, in temperatures of 26, 28 and 30ºC and photoperiod of 12 hours. The pathogenicity of the isolates and the reaction of the genotypes were evaluated in detached leaf and plant. The behavior of the genotypes were evaluated in two seasons, in the presence and absence of rain. The design was completely randomized to five and four replicates to evaluate the pathogenicity and genotypes, respectively. The cultural and morphological characteristics varied according with the isolates and conditions of the grown, but were compatible with those described for the species C. truncatum. The pathogenicity was proved no significant differences between the isolates. The first symptoms of the disease appeared to three days after inoculation in detached leaves and plants. The genotypes UFPI - 578, UFPI - 468 and UFPI - 26 were susceptible to C. truncatum. When evaluated in detached leaves did not differ significantly among themselves in the level of infection, independent of the season. In plants, UFPI - 26 was the most susceptible in season 2 with the highest level of infection, while the UFPI - 578 was the least susceptible. The positive and significant correlation (P <0.0001) between detached leaves and plant prove the viability of employment of detached leaves in studies related to this disease

Made available in DSpace on 2014-06-11T19:35:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-19Bitstream added on 2014-06-13T20:06:03Z : No. of bitstreams: 1 ramos_vm_dr_botfca.pdf: 300153 bytes, checksum: 36bf680224d1ffaf085ee93b9f674ede (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Empresa Privada / As formigas cortadeiras, insetos pertencentes aos gêneros Atta e Acromyrmex (Hymenoptera: Formicidae), recebem, no Brasil, os nomes populares de saúvas e quenquéns. Devido a seu hábito alimentar polífago ocupam diversos ambientes, acarretando danos econômicos em áreas cultivadas. As partes vegetais cortadas são transportadas para suas colônias e preparadas para servir de substrato ao fungo simbionte do qual se alimentam. Atualmente, o método mais empregado para o seu controle é a aplicação de iscas tóxicas, e, para muitas espécies, proporciona excelentes resultados. Porém, para uma espécie em particular, os métodos existentes são considerados insatisfatórios. Trata-se de Atta capiguara, conhecida como saúva parda, que causa expressivos prejuízos à pecuária. A ineficiência das iscas tóxicas destinadas ao controle dessa espécie deve-se ao fato de que as mesmas são fabricadas contendo apenas polpa cítrica; como A. capiguara seleciona essencialmente monocotiledôneas, as iscas não são atrativas e, conseqüentemente, não transportadas pelas operárias. Dessa maneira, o presente trabalho objetivou desenvolver iscas destinadas ao controle da saúva parda, partindo da hipótese que a adição de espécies monocotiledôneas à matriz das iscas causa efeito atrativo sobre as operárias, tornando os pelletes mais transportados. Assim, foram utilizadas espécies vegetais naturalmente selecionadas durante o forrageamento por essas formigas, no caso a cana-de-açúcar, o capim jaraguá e o capim elefante. A adição dessas gramíneas às iscas foi feita por meio de incorporação, impregnação e pulverização de extratos, além da adição direta de matéria seca vegetal em substituição parcial à polpa cítrica, sendo todo o material previamente preparado em laboratório... / The leaf-cutting ants, insects belonging to the genus Atta and Acromyrmex (Hymenoptera: Formicidae), they have, in Brazil, the popular names of saúvas and quenquéns. Due to its polyfagic habit, they live in the most several environments, bringing out economic damages in cultivated areas. The pieces of the vegetables that they cut, are transported for its colonies and prepared to serve of substratum to the symbiont mushroom which they feed. Now, the method more employed for its control is the application of toxicant baits, and, for a lot of species, it provides excellent results. Even so, for a species in particular, the existent methods are considered unsatisfactory. It is Atta capiguara, known as saúva parda, that causes expressive damages to the pastures. The inefficiency of the toxicant baits destined to the control of that species is due to the fact that the same ones are manufactured just contends citric pulp; as A. capiguara selects monocotyledonous essentially, the baits are not attractive and, consequently, not transported by the workers. In that way, the present work objectified to develop baits destined to the control of the saúva parda, based on hypothesis that the addition of monocotyledonous species to the base of the baits should cause an attractive effect on the workers, turning the pellets more transported by the same ones. Thus, were used vegetable species that they are naturally selected during the foraging by the ants, in this case sugar-cane, jaraguá grass and elephant grass. The addition of those grasses to the baits was made by incorporation, impregnation and pulverization of the extracts, besides the direct addition of dry vegetable matter in partial substitution to the citric pulp, being previously the whole material prepared in laboratory...(Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:35:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-20Bitstream added on 2014-06-13T19:24:09Z : No. of bitstreams: 1 cardoso_srs_dr_botfca.pdf: 2542117 bytes, checksum: 05184fee4ec69978c01502fbf878687b (MD5) / As formigas cortadeiras são consideradas pragas importantes para diversas plantas cultivadas, o que exige constante controle. No entanto, a mortalidade natural de colônias iniciais de Atta spp é alta, alcançando até 100%, no primeiro ano de fundação. Dentre vários fatores os micro-organismos patógenos são apontados como um dos responsáveis por tal mortalidade. Assim, o presente estudo teve como objetivo: (1) estudar a morfogênese dos ninhos iniciais em função do tempo de fundação essas espécies; (2) avaliar a taxa de mortalidade de rainhas de Atta bisphaerica e Atta sexdens rubropilosa, durante os primeiros meses de fundação; (3) isolamento e caracterização dos fungos entomopatogênicos de ocorrência natural em rainhas; (4) realizar bioensaios para avaliar a patogenicidade desses isolados em operárias de Atta sexdens rubropilosa e (5) formulação e aplicação de iscas à base de isolados de fungos entomopatogênicos, em colônias de Atta sexdens rubropilosa, visando possibilidades de aplicação prática. Para tal, foram coletadas rainhas recém-fecundadas ou provenientes de escavações dos ninhos incipientes marcados no período da revoada. As escavações ocorreram aos 20, 45, 90, 135, 180 e 225 dias de idade do ninho em 2007, e aos 20, 45 e 90 dias em 2008, e aos 60 dias em 2009. Foram obtidos os seguintes resultados: (1) as dimensões da câmara-recém fundada aumentam com o tempo de fundação; (2) altas taxas de mortalidade para A. bisphaerica e A. sexdens rubropilosa; (3) rainhas de Atta spp. podem ser parasitadas por diversos fungos, dentre eles Beauveria bassiana, Isaria lilacinus, Isaria fumosorosea e Aspergillus flavus; (4) todos os isolados são patogênicos e os mais virulentos BBOT11, BBOT12 de B. bassiana e IBOT33 de I. lilacinus; e (5) iscas formuladas com fungos são atrativas, carregadas e incorporadas por operárias de A. sexdens rubropilosa, contudo não causam / The leaf-cutting ants are pests for several important crop plants, which requires constant control. However, the natural mortality of Atta spp colonies is high, reaching 100% in the first year of foundation. Among many factors the pathogenic microorganisms are noted as one of those responsible for such mortality. Thus, this study aimed to: (1) study the morphogenesis of early nests depending on the time of foundation of these species; (2) assess the death rate of the queens of Atta bisphaerica and Atta sexdens rubropilosa during the first months of the foundation, through excavations in newly founded nests; (3) isolation and characterization of entomopathogenic fungi found in queens; (4) perform bioassays to assess the pathogenicity of these isolates in Atta sexdens rubropilosa and (5) formulation and application of baits based on entomopathogenic fungi isolated in colonies of Atta sexdens rubropilosa, seeking opportunities for practical application. To this end, we collected newly fertilized queens or from excavations of incipient nests marked during the time of nuptial flight. The excavations were performed at 20, 45, 90, 135, 180 and 225 days of nest age in 2007, and at 20, 45 and 90 days in 2008. The results were: (1) the dimensions of the incipient chamber increases with time of the foundation; (2) high rates of mortality for Atta bisphaerica and Atta sexdens rubropilosa; (3) queens of Atta spp. can be parasitized by several fungi, including Beauveria bassiana, Isaria lilacinus, Isaria fumosorosea and Aspergillus flavus; (4) all strains are pathogenic and the most virulent BBOT11, BBOT12 of B. bassiana and IBOT33 of I. lilacinus; and (5) baits made with fungi are attractive, loaded and incorporated by workers of A. sexdens rubropilosa, yet not cause mortality of the colony

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