EXPERIMENTATION ON APIGUARD - A CONTROLLED RELEASE GEL OF THYMOL AGAINST HONEYBEE DISEASES

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1 EXPERIMENTATION ON APIGUARD - A CONTROLLED RELEASE GEL OF THYMOL AGAINST DISEASES Dr Jérôme Trouiller and Dr Max Watkins VITA (Europe) Limited 21/23 Wote Street, Basingstoke, Hampshire, RG21 7NE, UK Tel.: , Fax: , max.watkins@vita-europe.com Introduction Thymol is well known for its curative properties for several honeybee diseases (varroatosis, tracheal mites, American and European foul brood, and chalk brood). Thymol has also the advantage of being of compound naturally occurring in honey. Thymol is of very low toxicity to humans and is used widely in the international food industry. However, several disadvantages limit the use of thymol in honeybee colonies : 1) Release dependent on external temperature : The rate of release of thymol in the hive is strongly dependent from the outside temperature. 2) Side effects : When temperature is high, thymol is released rapidly in the colony and can elicit a strong agitation of the colony, toxicity on brood and adults, and in some cases absconding. 3) Repetition of applications: Because thymol disappears quickly, the treatment has to be repeated to cover the entire capping period during which the mites are protected in the brood cells. 4) Residues : Thymol has a significant flavour, the repetition of thymol applications may impair the natural flavour of honey. 5) Safety : Thymol crystals can be harmful for the eyes of the operator. Controlled-release gel For many years, experiments have been conducted with a product based on a thymol controlled release gel called Apiguard. The gel can be likened to a sponge which counteracts the effects of external temperature. When temperature is high, the mesh of the gel decreases and limits the release of thymol. When temperature is low, the mesh increases and leaves the thymol to evaporate freely. Because of the gel, the rate of release of thymol is fairly constant and controlled. Only two applications are necessary to cover the capping period and give a good control of varroatosis. Mode of application Apiguard is presented in two types of packaging : 1) Trays : aluminium trays of 50g of gel (one application dose ready to use) for hobbyist beekeepers 2) Tubs : tubs of different dimensions (several uses, to be dosed by the operator) for professional beekeepers or beekeepers with more than, say, 15 hives. One treatment consists in two application of 50 g of gel at a two week interval. The gel is placed on the top of the brood frames to allow the vapour of thymol to pass through the colony and the brood nest. The application can be performed following two methods : 1) Standard : The tray is placed directly on the top of the frames, gel side up. 2) Spread : For the tub or for the trays when external temperature is low, the gel is spread on a flat surface of 10 x cm (for example a piece of wax foundation, a plastic sheet ) placed on top of the brood frames. Proceedings of the 37 th International Apicultural Congress, 28 October 1 November 2001, Durban, South Africa APIMONDIA 2001 To be referenced as: Proc. 37 th Int. Apic. Congr., 28 Oct 1 Nov 2001, Durban, South Africa ISBN: Produced by: Document Transformation Technologies Organised by: Conference Planners

2 Experiments Many experiments have been conducted on varroatosis in different climatic conditions by official research institutes of many countries. In every test, normal field conditions were used, treatment was performed at the normal varroa treatment period, bee brood was present, the colonies tested presented different strength and mite infestation, tests were performed using various honeybee strains, and different hive types. The experimental method to evaluate efficacy consisted in an Apiguard treatment (2 applications) followed by a control treatment or several control treatments. The choice of the control treatment took into account the possible presence of mite resistance to acaricides in the experimental sites. In case of uncertainty, two treatments using active ingredients of different chemical family were used. The mite fall was recorded using a screened bottom board and by counting the fallen mites regularly (1 to 7 days). Several methods of application and posologies were tested : 1) Application of Apiguard in trays (2 times 50g at a 2 week interval) 2) Application of Apiguard on a flat surface (2 times 50g at a 2 week interval) 3) Application of Apiguard on a flat surface (2 times 25g at a 1 week interval) Results 1) Application of Apiguard in trays (2 x 50g at a 2 week interval) ALGERIA 5 Langstroth 15 Dadant Lombardy 1 15 Dadant Lombardy 2 Lombardy 3 Lombardy 4 Lombardy 5 MOROCCO 5 Dadant MOROCCO 5 Dadant 10 Langstroth 1 Ligus./carn. 2 Ligus./carn. BELGIUM 1 14 IG BELGIUM 2 5 Dadant BELGIUM 3 1 Dadant BELGIUM 4 15 Mixture AUG-SEP JUL-AUG JUL-AUG JUL-AUG JUL-AUG JUL-AUG JUN-JUL AUG-SEP SEP-OCT JUN-JUL JUN-JUL AUG-SEP AUG-SEP? AUG-SEP? AUG-SEP

3 BELGIUM 5 9 Mixture AUG-SEP? SWITZERL 1 10 Swiss AUG-SEP SWITZERL 2 AUG-SEP SWITZERL 3 10 Swiss AUG-SEP SWITZERL 4 3 Dadant AUG-SEP SWITZERL 5 3 Swiss AUG-SEP SWITZERL 6 10 Swiss AUG-SEP SWITZERL 7 AUG-SEP Dadant OCT-NOV Zander SEP-OCT Continental 2 Zander SEP-OCT Continental ) Application of Apiguard on a flat surface (2 x 50g at a 2 week interval) MOROCCO JUN-JUL Langstroth SEP-OCT MOROCCO 9 Dadant SEP-OCT Atlantic 2 5 Dadant AUG-SEP? Alps 1 SWITZERL 1 13 Langstroth JUL-AUG SWITZERL 2 9 Dadant JUL-AUG Dadant SEP-NOV Alps 2 MOROCCO NOV-JAN Atlantic 3 5 Dadant SEP-NOV Alps 3 7 Dadant SEP-OCT SWITZERL 3 10 Swiss JUL-AUG Dadant SEP-NOV? Atlantic

4 3) Application of Apiguard on a flat surface (2 x 25g at a 1 week interval) TUNISIA 1 9 Langstroth AUG-SEP TUNISIA 2 8 Langstroth SEP-OCT MOROCCO 8 Dadant JUN-JUL Langstroth SEP-OCT MOROCCO SEP-OCT Atlantic 2 5 Dadant AUG-SEP? Alps 1 8 Dadant SEP-NOV Alps 2 5 Dadant SEP-NOV Alps 3 4 Dadant SEP-OCT Dadant SEP-NOV? Atlantic Conclusion Side effects : Apiguard was shown to be well-tolerated by honeybees even in high temperature conditions of Africa. However, when external temperature was high, some agitation was observed at the entrance of the colonies. Repetition : Only two applications are necessary to cover the capping period. Residues : When used out of harvest period, Apiguard has no effect on the natural flavour of honey. Safety : Because of its gel structure, Apiguard is a much safer presentation of thymol for the user. Temperature : The dependence of efficacy with temperature was reduced. However, external temperature must be higher than 15 C during a significant period to provide an efficient control of varroatosis. The use of 2 applications of 25g in spite of 2 applications of 50g seems to be only efficient when external temperature was over C. At that dosage (2 x 25g) optimum efficacy was reached in hot climates.

5 EXPERIMENTATION ON APIGUARD - A CONTROLLED RELEASE GEL OF THYMOL AGAINST DISEASES Dr Jérôme Trouiller and Dr Max Watkins VITA (Europe) Limited 21/23 Wote Street, Basingstoke, Hampshire, RG21 7NE, UK Tel.: , Fax: , max.watkins@vita-europe.com Curriculum Vitae Dr Max WATKINS Born 1959 in Wales, UK Biologist, specialising in novel insect control methods, especially pheromones and insect juvenile hormones M.Sc. Southampton University (Novel insect control methods) Followed by several years working in industrial pest control Ph.D. Cardiff University (Pheromonal control of cockroach behaviour) [Industry Award] Technical Development Manager for Sandoz SPC for Europe, Middle East and Africa 1997 co-founded Vita (Europe) Limited as a Management buy out from Novartis. Director, concerned with product development, registration and commercialisation. Vita (Europe) Limited is a small company specialising in honeybee health. Dr Jérôme TROUILLER Born at Paris in : phd of Biochemistry at Paris University, thesis on chemical communication in honeybees : Post Doc at Simon Fraser University on brood pheromones : Study on varroa resistance to acaricide at Udine University (Italy) Since 1997 : Technical Manager at VITA (Europe) Ltd (UK) a company dedicated to honeybee health