Plantas medicinais: efeito sobre insetos-praga e seus inimigos naturais

• Autor(a) principal: Flavia Silva Barbosa
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/NCAP-8A2HRS
• topic: Ruta graveolens; metodologias de extração; agricultura orgânica; Chenopodium ambrosioides; agroecologia; Copaifera langsdorffii; Plantas medicinais Pesquisa; Agroecologia; Inseticidas vegetais; Entomologia; Agricultura orgânica

The objective of this study was to identify among the medicinal plants Ruta graveolens L. (Rutaceae), Artemisia abisinthium L. and A. verlotorum L. (Asteraceae), Stryphnodendron adstringens Mart. (Leguminosae), Baccharis trimera Less. (Asteraceae), Copaifera langsdorffii Desf. (Caesalpinaceae), Petiveria alliacea L. (Phytolaccaceae) and Chenopodium ambrosioides L. (Chenopodiaceae) which possesses potential insecticide for agricultural use suitable with the principle of Agroecology. Different extractors (distilled water, commercial vegetable oil and commercial ethyl hydrated alcohol), as well as extraction and concentration methodologies (2, 5, 10 or 15% of the extract) were tested in two bioassays, in laboratoryal conditions, as the mortality of Diabrotica speciosa Germar (Coleoptera: Chrysomelidae), in 24 and 48 hours of exhibition, caused by contact and feeding. The first bioassay verified that the extract of R. graveolens in water in 5% ofconcentration, after 48 hours, it presented larger corrected mortality of D. speciosa (32.5%). In the second bioassay it was verified that, after 48 hours, the 5% alcoholic extract of C. langsdorfii presented larger mortality of this pest (35.0%), followed by the 5% alcoholic extract of C. ambrosioides (22.5%) compared to the other extracts of the plants in study. In the bioassays, the extracts that used commercial soy oil assolvent, presented larger mortality of D. speciosa and in their witness (solvent = oil). However, the oil is not recommended as solvent because the concentrations that presented larger mortalities are caused by the solvent and not by the present active priciples in the medicinal plants. The field experiment regarded the most effective results in the control of D. speciosa in laboratory. It was observed in field that there was a reduction in the population of arthropods in the portions treated in comparison with the ones which didn't have any treatment. The extract elaborated with R.graveolens was shown to be more selective to natural enemies than C. langsdorffii and C. ambrosioides, fact that shows the importance of more studies with these plants in order they could be used in agroecological cultivations.