Evaluation of the Toxic Effect from Eupatorium Microphyllum L.F. (Asteraceae) Extracts on Aedes Aegypti Larvae (Diptera: Culicidae) in Laboratory Conditions

In the present work the toxic activity of extracts of Eupatorium microphyllum L.F. was evaluated on 4th instar larvae of the mosquito Aedes aegypti (Linneaus), under laboratory conditions. Aqueous extracts were utilized in concentrations of 500 mg L-1, 1,500 mg L-1 and 2,500 mg L-1 and acetone in concentrations of 10 mg L-1, 20 mg L-1, 30 mg L-1, 40 mg L-1and 50 mg L-1. The bioassays were carried out for triplicate each one with 20 larvae, exposed for 24 hours to 150 mL of solution. In all the bioassays were employed control groups. In the evaluation of the acetone extracts, a negative control was employed to avoid that the mortality of the larvae to occur on account of the solvent. The Aqueous extracts showed low moderate action in the mortality of larvae, less than 20%. On the contrary, the action of the acetone extracts was observed to 10 and 20 mg L-1with 15% of mortality, while to 30 and 40 mg L-1 were registered 22 to 38% of mortality. However, to 50 mg L-1 the mortality was of 95.4% with highly significant statistical results. The concentrations of the acetone extracts showed to be the most efficient for the control of the mosquitoes selected. Both types of extracts showed toxic effect in larvae of A. aegypti, nevertheless, greater effect in the acetone extracts was observed relating to the aqueous extracts of E. microphyllum, which constitutes a viable alternative in the search of new larvicides from composed natural.

Biodiversidad, cultura y territorio

After several decades of systematic nature destruction, the discourse on biodiversity is the answer of what might be called “the irruption of the biological”, i.e. the biotic issue surviving as the core issue of the modern order. In this regard, the biodiversity discourse declares itself the sponsor of saving nature from destructive practices and capable to institute a culture of conservation instead. Nevertheless, there remain gaps in the discourse, which have been intended to be fi lled with discussions addressing lately the relevance of the local knowledge, the ways of life –habits and customs– and the traditional production, within the frame that supports the meaning of biodiversity. On the one hand, for industrialized countries governments and international governmental institutions, traditional knowledge is an asset of the humankind, which improved becomes a technological innovation that may be subject to patent and fi nally traded, without any benefit to the owners of the basis knowledge. On the other hand, for peasants, intellectuals, and local knowledge activists, ways of life and tradicional production are the basis for rebuilding the peasants’ and natives’ territory, to strengthen the limited independence and self-suffi ciency they live with, but with their active involvement in the determination of everything that affects them. Based on these considerations, spaces are being built to provide an answer to privatization, an answer based on the concept of “the communal” (Grain, 2005).