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| Silva,Alexandre de Almeida e; Varanda,Elenice Mouro; Primavesi,Ana Cândida. |
| Plants have inherent variability of mineral content which affects their physiology and consequently the herbivorous insects feeding on them. Besides, insects need considerable amounts of potassium, phosphorus and magnesium in their diets, whereas little calcium, sodium and chloride are required. In this study, the inherent variation on mineral (Ca, S, Mg, N, P, K and also C:N ratio) concentrations and aphid (Acyrthosiphon spp., Therioaphis maculata, Aphis craccivora) populations on three alfalfa (Medicago sativa) cultivars (P3; Crioula, the most widely cultivated in Brazil, and CUF 101, an aphid-resistant) were studied between September/1997 and August/1998. A significant variation on mineral concentrations and aphid populations was observed among... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aphididae; Insecta; Nutrients; Resistance; Plant-insect relation. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052005000200010 |
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| Pais,Mara Patrícia; Varanda,Elenice Mouro. |
| Cerrado vegetation is composed of a mosaic of vegetation types, from campo sujo, dominated by herbs; campo cerrado and cerrado sensu stricto, with shrubby vegetation; to cerradão, with trees forming a denser forest. This physiognomic mosaic is related to differences in the water availability in the soil. Cerrado plants are considered physically and chemically well defended against herbivores, but there are no studies showing how plants allocate investment to various types of defensive mechanisms in different habitat physiognomies. The defensive mechanisms and the nutritional traits of a cerrado plant, Didymopanax vinosum (Cham. & Schltdl.) Seem. (Apiaceae), were compared along a vegetation gradient. Toughness, as well as water, nitrogen, cellulose,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cerrado; Plant defenses; Tannins; Vegetation gradient; Water stress. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062003000300007 |
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| Silva,Alexandre de Almeida e; Varanda,Elenice Mouro; Rassini,Joaquim Bartolomeu. |
| It is important to understand the effects of weather, insect density and plant cultivar on insect abundance to predict and prevent crop production loss. The present work investigated the influence of such factors on aphid in alfalfa during one year (short term). Data was collected from September/1997 to August/1998 at Canchin Farm (CCPSE-EMBRAPA), São Carlos, State of São Paulo, Brazil. Weather conditions had, in general, little effect on the variation of aphid populations, but Therioaphis maculata abundance was negatively correlated to humidity. Moreover, high maximum temperatures and low levels of rainfall possible favored T. maculata high abundance on Crioula and P3 cultivars. Therefore, appropriate management of this species is required during hot and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Herbivory; Hemiptera; Medicago sativa; Resistance; Population dynamics. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052007000200012 |
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