RESUMO
Extracts of indigenous plants from South America have shown a broad spectrum of bioactivities. No-contaminant and natural substances have recently resurged as control treatment options for varroosis in honey bee colonies from Argentina. The aim of this work was to evaluate the biological activity of botanical extracts from Baccharis flabellata and Minthostachys verticillata on Varroa destructor and Apis mellifera. The acaricidal and insecticidal activities were assessed by the spraying application method. Both ethanolic extracts showed high levels of toxicity against the mites and were harmless to their host, A. mellifera. During the attractive-repellent test, the olfactory stimulus evoked for the extract from B. flabellata resulted as a repellent for mites. The aromatic stimulus of these extracts would be strong enough to cause disturbance on the behavior of V. destructor. Thus, the repellent effect of these substances plus the toxicity on mites postulate these botanical extracts like promising natural compound to be incorporated for the control of varroosis.
Assuntos
Acaricidas/farmacologia , Baccharis/química , Repelentes de Insetos/farmacologia , Lamiaceae/química , Extratos Vegetais/farmacologia , Varroidae/efeitos dos fármacos , Acaricidas/isolamento & purificação , Acaricidas/toxicidade , Animais , Argentina , Abelhas/efeitos dos fármacos , Feminino , Repelentes de Insetos/isolamento & purificação , Repelentes de Insetos/toxicidade , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/toxicidade , Análise de SobrevidaRESUMO
Varroa destructor is an ectoparasitic mite that affects colonies of honey bee Apis mellifera worldwide. In the last years, substances of botanical origin have emerged as natural alternative acaricides to diminish the population levels of the mite. In the present work, the bioactivity of propolis from different geographical locations of Pampean region from Argentina on V. destructor was evaluated. Fourteen propolis samples were organoleptic and physicochemically characterized and, by means topical applications, their activity was tested on mites. All propolis had a homogeneous composition and the bioactivity levels against mites were comparable among the different propolis samples. The percentage of mites killed by the treatments ranged between 60.5% and 90% after 30 s of exposure. Thus, V. destructor was highly susceptible to propolis. Moreover, the mites remained anesthetized during the first hours after topical treatment. The results suggest that propolis from Argentinean pampas could be incorporated in honey bee colonies as acaricidal treatment by spraying.
Assuntos
Acaricidas/farmacologia , Própole/farmacologia , Varroidae/efeitos dos fármacos , Animais , Argentina , Geografia , Análise de SobrevidaRESUMO
Varroa destructor is an external parasitic mite that is a serious pest of honeybees and has caused severe losses of colonies worldwide. One of the feasible alternative treatments being used for their control is essential oils. The aim of this work was to evaluate the bioactivity of some essential oils on V. destructor and Apis mellifera in relation with their chemical composition and physicochemical properties. Lavender, lavendin and laurel essential oils showed linalool as main compound in their composition. 1,8-Cineole was also present as a predominant component in the laurel essential oil. However, thyme oil was characterized by a high concentration of thymol. Mites and bees toxicity was tested by means of complete exposure method. For mites, LC(50) values for laurel, lavender and lavendin essential oil did not show significant variation throughout all observation times. However, the LC(50) values for thyme oil at 48 and 72 h were lower than at 24 h. Bee mortality was evident only in treatment with thyme oil. At 48 and 72 h, lavender essential oil presented better selectivity indexes. In this research, all essential oils caused mite mortality without severe harmful effects on adult bees. The simultaneous evaluation of the physicochemical analysis of the essential oils, the characterization of the dosage response relationships among them, and the mortality effects on mite and bees, give us the possibility to obtain comparative results for future research in Varroa control.