Romanian Biotechnological Letters Vol. 22, No. 6, 2017 Copyright © 2017 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER Romanian Biotechnological Letters, Vol. 22, No. 6, 2017 13182 The effect of using medicinal plant extracts upon the health of bee colonies Received for publication, February 11, 2016 Accepted, August 30, 2016 SILVIA PĂTRUICĂ 1 *, DANIELA MOȚ 1 , DANIEL POPOVICI 2 1 Banat’s University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" from Timisoara, Faculty of Animal Sciences and Biotechnology, Calea Aradului, 119, 300645, Timisoara, Romania 2 Beekeeper * Address correspondence to: Banat’s University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" from Timisoara, Faculty of Animal Sciences and Biotechnology, Calea Aradului, 119, 300645, Timisoara, Romania, Phone: +40723235653, Email: patruica_silvia@yahoo.com Abstract The productive potential of honeybee colonies is dependent on their state of health. The use of medicinal plant extracts in the end-of-winter protein-energy feed provided to bee colonies can furnish a method both for the improvement of bee health and for early mobilisation of colony numbers, with a major positive impact on honey yield. The feeding of bee colonies with protein-enriched candy in which extracts of garlic (Allium sativum), Echinaceea purpurea, Ganoderma lucidum and sage (Salvia officinalis) extracts had been incorporated has been shown both to stimulate queen brood laying and to lead to a reduction in the numbers of bee intestinal bacteria. Keywords: honeybee, garlic extract, Echinaceea extract, Ganoderma extract, sage extract 1. Introduction Medicinal plants contain significant quantities of antimicrobial substances (LEWIS & ASUBEL [1]), which can be used as an alternative to antibiotics in prophylactic treatment of some bee diseases (FLESAR & al. [2], MĂRGHITAȘ & al. [3]). Extensive research has been done on the effectiveness of such utilisation of plant extracts arising from their antibacterial, antiviral, antifungal, and anti-inflammatory properties (MĂRGHITAȘ & al. [3], PĂTRUICĂ & al. [4], PĂTRUICĂ & al. [5], MĂRGHITAȘ & al. [6], PĂTRUICĂ & al. [7], ZAROG & BASSIOUNY [8], QAYYOUM & al. [9]). Research using both Apis mellifera and Apis carnica bee colonies infested with Varroa jacobsoni and Varroa destructor parasites has demonstrated the value of medicinal plants in the eradication of diseases (ZAROG & BASSIOUNY [8], QAYYOUM & al. [9], MAHMOOD & al. [10]). The antimicrobial effect of bay leaves (Laurus nobilis) on the bacterium Paenibacillus larvae that causes American Foulbrood disease was shown by (MAGGI & al. [11]). These authors also noted the anti-parasite effect of bay leaves on Varroa destructor and Nosema ceranae parasites. Similar results had been obtained by (PORINI & al., [12] and DAMIANI & al. [13]). Results which highlight antimicrobial activity on the Paenibacillus larvae bacterium were obtained using extracts of basil (Ocimum basilicum), nettle (Urtica dioica), thyme (Satureja hortensis) and yarrow (Achillea millefolium) (MĂRGHITAȘ & al. [6]), DAMIANI & al. [13], POHORECKA [14]).