The qualitative and quantitative composition of the essential oil from aerial parts of Eupatorium buniifolium Hooker et Arnott (Asteraceae) has been investigated for the first time. The essential oils were obtained by steam distillation of leaves and analysed by GC-MS; 44 components were identified. Monoterpene and sesquiterpene hydrocarbons, especially α-pinene (14.7%), β-elemene (12.2%), germacrene D (11.5%), trans-β-guaiene (6.5%) and (E)-caryophyllene (4.3%), were the major constituents found in the oils. The characterisation of E.

Abstract:Honeybees Apis mellifera are important pollinators of wild plants and commercial crops. For more than a decade, high percentages of honeybee colony losses have been reported worldwide. Nutritional stress due to habitat depletion, infection by diferent pests and pathogens and pesticide exposure has been proposed as the major causes. In this study we analyzed how nutritional stress afects colony strength and health.

ABSTRACT. In countries where livestock production based on native grasslands is an important economic activity, information on structural characteristics of forage is essential to support national policies and decisions at the farm level. Remote sensing is a good option for quantifying large areas in a relative short time, with low cost and with the possibility of analyzing annual evolution. This work aims at contributing to improve grazing management, by evaluating the ability of remote sensing information to estimate forage height, as an estimator of available biomass.