14 resultados para ressurgência de pragas

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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Onion (Allium cepa) is one of the most cultivated and consumed vegetables in Brazil and its importance is due to the large laborforce involved. One of the main pests that affect this crop is the Onion Thrips (Thrips tabaci), but the spatial distribution of this insect, although important, has not been considered in crop management recommendations, experimental planning or sampling procedures. Our purpose here is to consider statistical tools to detect and model spatial patterns of the occurrence of the onion thrips. In order to characterize the spatial distribution pattern of the Onion Thrips a survey was carried out to record the number of insects in each development phase on onion plant leaves, on different dates and sample locations, in four rural properties with neighboring farms under different infestation levels and planting methods. The Mantel randomization test proved to be a useful tool to test for spatial correlation which, when detected, was described by a mixed spatial Poisson model with a geostatistical random component and parameters allowing for a characterization of the spatial pattern, as well as the production of prediction maps of susceptibility to levels of infestation throughout the area.

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Piperaceae species have been placed among the basal angiosperm and are adapted to a variety of habitats including moist forests, secondary vegetation and dry high lands. The major anatomical/morphology features are of small trees, vines, and shrubs for Piper species, while the epiphytic and succulent characteristics are predominant forms among Peperomia species. Their secondary chemistry can be mostly represented by amides, phenylpropanoids/lignoids, and chromenes in addition to a phletoria of biosynthetically mixed-origin secondary compounds. Although several amides and lignans are known as insecticides, several phytophagous insects, among which some considered pests of economic importance, have been observed feeding vigorously on Piperaceae species. Herein we describe the feeding preferences of fourteen phytophagous species of Coleoptera, Lepidoptera and Hemiptera over approximately fifty Piperaceae species observed in São Paulo, SP, Brazil, in a long-term basis.

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Data collected during an oceanographic cruise along the southeastern Brazilian coast from Cape Frio (22° 58' S) and Paraná (27° 50' S) in March 1982 showed that the marine insect Halobates micans occurred along the Southeastern Brazilian Bight, but in lower abundance in low-temperature areas due to the intrusion and upwelling of South Atlantic Central Water, and in low-salinity areas in Coastal Water. Insect capture was higher at night and in the oligotrophic Tropical Water. The number of nymphs and adult females was higher, probably because of an active breeding season during the austral summer. Adult sex ratio was 1.3:1.0 (F:M). Floating gas vesicles of benthic Sargassum spp. and petroleum lumps were used by females for egg-laying.

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The aim of this work was to generate an inventory of the data on radiocarbon datings obtained from sediments of the São Paulo Bight (southern Brazilian upper margin) and to analyze the data in terms of Late Quaternary sedimentary processes and sedimentation rates. A total of 238 radiocarbon datings from materials collected using differents ampling procedures was considered for this work. The sedimentation rates varied from less than 2 to 68 cm.kyr-1. The highest sedimentation rate values were found in a low-energy (ría type) coastal system as well as in the upwelling zones of Santa Catarina and Cabo Frio. The lowest rates were found on the outer shelf and upper slopes. Our results confirm the strong dependency of the shelf currents, with an emphasis to the terrigenous input from the Río de La Plata outflow which is transported via the Brazilian Coastal Current, as well as of the coupled Brazil Current - Intermediate Western Boundary Current (BC-IWBC) dynamics on the sedimentary processes. At least three indicators ofthe paleo sea level were found at 12200 yr BP (conventional radiocarbon age) (103 meters below sea level - mbsl),8300-8800 cal yr BP (13 mbsl) and 7700-8100 cal yr BP (6 mbsl).

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Este trabalho tem por objetivo identificar e caracterizar as feições oceanográficas de pequena e mesoescala que ocorrem na plataforma continental de Santa Catarina (SC). Foram empregadas imagens de temperatura e concentração de clorofila da superfície do mar (TSM e CSM), obtidas pelo sensor MODIS. Foi selecionada uma imagem diária para cada mês do ano de 2003, excetuando dezembro, onde procurou-se avaliar efeitos sazonais. As feições oceanográficas foram observadas através da aplicação de diferentes níveis de contraste e paletas de cores para realce. Foram identificadas feições como vórtices, meandros, cogumelos, plumas, filamentos, frentes e áreas de ressurgências. Os resultados indicam que no verão a distribuição superficial em mesoescala da temperatura é mais homogênea, levando a um número menor de feições observáveis. O fenômeno de ressurgência costeira em escala localizada ao sul da Ilha de SC e junto à costa foi observado nos meses de novembro, janeiro e fevereiro. Durante o outono e o inverno as imagens apresentaram maior grau de complexidade, principalmente devido à presença da frente costeira do Prata, com características de menor temperatura e maiores valores de clorofila.

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O feijão caupi é uma das principais culturas alimentares do Nordeste brasileiro. Para melhorar sua resistência contra pragas e produtividade, a nova cultivar (BRS-Milênio) foi obtida por melhoramento genético. Este trabalho objetivou caracterizar o potencial nutricional desta variedade, determinando-se a composição centesimal, o perfil de aminoácidos e ácidos graxos, o conteúdo de minerais e a atividade inibitória de tripsina. A semente contém (g.100 g-1): 24,5 de proteínas; 51,4 de carboidratos; 16,6 de fibra insolúvel e 2,7 de fibra solúvel; 2,6 de cinzas, tendo como principais minerais (mg.100 g-1): ferro - 6,8; zinco - 4,1; manganês - 1,5; fósforo - 510,0 e potássio - 1430,0. O teor de lipídios foi de 2,2%, e seu perfil de ácidos graxos apresenta 29,4% de saturados e 70,7% de insaturados. Foi estimado valor calórico de 323,4 kcal.100 g-1 de semente. Encontrou-se baixa atividade inibitória de tripsina (8,0 UIT.mg-1 de amostra). O perfil de aminoácidos foi favorável ao padrão de referência, exceto pela deficiência de sulfurados, sugerindo a necessidade da combinação desta leguminosa com outras fontes alimentares. Os resultados indicam que o feijão caupi possui atributos desejáveis como altos teores de energia, proteínas, fibras e minerais, baixa atividade inibitória de tripsina e, apesar de reduzido conteúdo lipídico, contém alta proporção de ácidos graxos insaturados.

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The weevil subfamily Scolytinae includes beetles which may feed on the bark, trunk or roots of both live and dead trees and are sometimes considered forest and silvicultural pests. Less frequently, some species feed on seeds and may be cause economic losses when associated to plant cultivars. Spermophthorus apuleiae Costa-Lima is a Neotropical Scolytinae formerly recorded to be "associated" with seeds of Caesalpinia ferrea var. leiostachya Benth, a Brazilian tree popularly known in Portuguese as "pau-ferro". Hitherto, it was not clear whether these beetles actually feed on the seeds of that plant. In order to investigate the ability of S. apuleiae to feed on seeds of "pau-ferro", observations were done and colonies of these beetles were established. Both in the field and in captivity the beetles were not observed feeding on the seeds. Even when beetles were exposed to seeds as the only source of food they were incapable of boring or eating the seeds and died. Our data therefore suggest that S. apuleiae is a frugivorous species which peculiarly does not eat seeds of "pau-ferro".

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Hundreds of plant species have been studied in order to find out the active ingredient responsible for their insecticidal activity against the pests of economic importance. To verify the insecticidal activity in the husk of stem of Croton urucurana Baillon 1864 (Euphorbiaceae) against Anagasta kuehniella Zeller 1879 (Lepidoptera: Pyralidae), the methanolic (EMeOH) extract, dichloromethane fraction (FDM), ethyl acetate fraction (FAE) and crude resin, incorporated into an artificial diet were evaluated. EMeOH (0.5, 1.0 and 2.0%) and crude resin (2.0%) interfered with neither the weight nor the survival of fourth instar larvae and other analyzed parameters. FDM (2.0%) fraction caused mortality of 65%, and the artificial diet containing 2.0, 1.0 and 0.5% FAE caused 100, 55 and 68% mortality respectively when compared with the control, confirming the least efficiency rates of food conversion for FDM(2.0%) and FAE(1.0%). The tryptic analysis performed with the midgut fluid of fourth-instar larvae demonstrated that tryptic and chymiotryptic activities for the larvae fed artificial diet containing EMeOH and crude resin were not different.

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Phytochemical investigation of the bark of Guatteria hispida afforded three new alkaloids, 9-methoxy-O-methylmoschatoline (1), 9-methoxyisomoschatoline (2), and isocerasonine (3), along with 10 known alkaloids, 8-oxopseudopalmatine (4), O-methylmoschatoline (5), lysicamine (6), liriodenine (7), 10-methoxyliriodenine (8), nornuciferine (9), anonaine (10), xylopine (11), coreximine (12), and isocoreximine (13). The major compounds, 2, 6, 12, and 13, showed significant antioxidant capacity in the ORAC(FL), assay. Compounds 5, 6, and 7 were active against S. epidermidis and C. dubliniensis, with MIC values in the range 12.5-100 mu g mL(-1).