Toxicidade do óleo essencial de Melaleuca a organismos não-alvo

Abstract

The increase in crops in agroecosystems favors the emergence of insect pests, with this, there is an increase in the use of synthetic insecticides. When analyzing ways to control these insect pests without causing damage to non-target organisms and the environment, more selective or safer means are sought. In this sense, the use of botanical insecticides such as the essential oil of Melaleuca alternifolia has been studied and used. However, the effects of essential oils on bees and mammals are little known. In this sense, the objective was to evaluate possible toxicity of the essential oil of M. alternifolia (OEMa) on two biological models, an invertebrate Apis mellifera africanizada (bee) and a vertebrate, the embryo of Gallus gallus domesticus (hen). For this, a concentration of 0.75% of OEMa was used in both experiments with biological models. In bees there were three types of exposure: 1) indirect spraying of OEMa in bees; 2) direct spraying of OEMa on bees; 3) OEMa incorporated into the feed. The analyzes were: probability of survival, vertical displacement test (flight) and flight resumption (fall) of the bees. The OEMa, when sprayed directly on A. melífera workers, reduced their probability of survival after 120 hours. In the bioassay with vertebrates, the embryos of G. gallus were submitted to two types of exposure: 1) external spraying of OEMa on the egg of G. gallus; 2) Injection of OEMa into the inside of the G. gallus egg. Analyzes were carried out: viability, probability of survival, heart rate, occurrence of malformations and stages of development of G. gallus embryos. Exposure to OEMa injected into the egg negatively affected G. gallus, causing malformations within three days of incubation. OEMa is selective and safe both for bees (provided it is sprayed at times when A. mellifera is less active) and for G. gallus embryos (sprayed externally on the egg).