4 resultados para Insect soil
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
Resumo:
One of the factors that affect the control of brown - roots environmental bedbug is the wide availability of plant species. Thus, this study aimed to evaluate the migration of nymphs of the brown - roots between plant species of economic importance and invasive stinkbug. Eight species of plants have been established in a set formed by eight circular PVC containers, connected symmetrically with free communication to a central circular container. The experiment was arranged in a completely randomized design and consisted of eight treatments and six replications. The test evaluations were performed on 15o , 30o , 45o and 60o days after the release of the nymphs, by counting the insects that migrated to the roots of different plants. It was observed that by the 30o day of early release nymphs, no significant differences (P < 0,05) in the choices nymph by plants. B. alata at 15 days of initial release and B. alata and grass-dictyoneura at 30 days were plants that had higher migration. All counts were carried out on 45o and 60o days, the migration of U. brizantha cv. Marandu presented significantly higher than all other species tested plants nymphs.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
After the prohibition of organochlorine-pesticide use in Brazil for controlling insect vector diseases, Mato Grosso State gathered the exceeding DDT and stored it irregularly in an open air area that belongs to the National Health Foundation, causing soil contamination. This study aimed to evaluate the contamination level and dissipation of p,p′-DDT and p,p′-DDE in this area. For that, surface soil samples were collected on 19 September 2000, 15 December 2000, 4 April 2001 and soil samples 30-40 cm; 60-70 cm and 90-100 cm deep were taken from five points in the studied area on 17 July 2001. The contaminants were determined by a small scale method which consists on extraction and clean-up steps combined into one step by transferring soil samples mixed with neutral alumina to a chromatographic column prepacked with neutral alumina and elution with hexane:dichloromethane (7:3 v:v). The eluate was concentrated and the analytes were quantified by gas chromatography with an electron-capture detector. p,p′-DDT at surface soil ranged from 3800 to 7300 mg kg -1. 30-40 cm deep soil sample concentrations varied from 0.036 to 440 mg kg -1 while 90-100 cm deep samples varied from 0.069 to 180 mg kg -1. Volatilization is probably the main dissipation process. The p,p′-DDT is moving slowly downward in the soil profile, however, the levels of this contaminant are high enough to present risk to underground waters. © 2005 Elsevier Ltd. All rights reserved.