Comparison Between Two Thymol Formulations in the Control of Varroa destructor: Effectiveness, Persistence, and Residues

Abstract

An apiary trial on the use of two acaricide formulations (gel-Apiguard and vermiculite and Api Life VAR) in the control of Varroa destructor (Anderson & Trueman) was conducted in summer 2001 in Sardinia (Italy). The main goals were 1) to determine their effectiveness against V. destructor, taking into account natural mite mortality in control hives; and simultaneously 2) to determine the persistence of both formulations and residues in honey and wax, by using a new extraction method. Both thymol formulations, after the treatments, reduced significantly the levels of mite infestations of adult bees and sealed brood, but their efficacy, expressed as percentage of mortality, was lower for both products (Api Life VAR 74.8 +/- 13.1 and 81.3 +/- 15.5, Apiguard 90.4 +/- 8.3 and 95.5 +/- 8.7 for sealed brood and adult bees, respectively) than the efficacy previously obtained with the same products in other experimental conditions. Moreover, a considerable colony-to-colony variability was recorded, and a significant negative effect of the thymol treatments on colony development was observed. During 2 wk of treatment, the bees removed nearly 95% of all the applied product (gel or vermiculite). Residues found in honey collected from the nest varied from 0.12 to 4.03 mg/kg for Api Life VAR and from 0.40 to 8.80 mg/kg for Apiguard. The residues were relatively higher in wax (Api Life VAR = 21.6 +/- 13.0; Apiguard = 147.7 +/- 188.9) than in honey, because thymol is a fat-soluble ingredient.

The Effects of Some Drugs Used to Treat Honeybee (Apis mellifera L.) Diseases and Pests on Lifespan of Honeybees

“…The results of this study support the similar results as seen the possible reasons of bee deaths of some drugs used for colony treatment informed by many researchers (Drescher and Schneider, 1987;Colin and Belzunces, 1992;Wallner, 1999;Morse and Calderone, 2000;Floris et al, 2004;Bogdanov, 2006, Chauzat et al, 2006Martel et al, 2007;Alaux et al, 2010;Johnson et al, 2009;Johnson et al, 2010;Le Conte et al, 2010;VanEngelsdorp and Meixner, 2010). In natural life cycle, lifespan of worker bees show significant changes depending on genetic structure, season and environmental factors (Ritter, 1988;Morse and Flottum, 1997).…”

Evaluation of Metarhizium anisopliae var. anisopliae Qu-M845 Isolate to Control Varroa destructor (Acari: Varroidae) in Laboratory and Field Trials

“…Another alternative control is the use of oils and organic acids such as formic acid, oxalic acid, and thymol, which have been intensively studied in Europe and Asia. In spite of its effectiveness in controlling varroa, damaging effects have been reported on bees, such as alteration in the recognition of the queen's oviposition, bee mortality, and caustic effects on the skin of the handler (Calderone, 1999;Kanga et al, 2003;Floris et al, 2004). …”

Short communication. Comparison of the efficacy of Apiguard (thymol) and Apivar (amitraz) in the control of Varroa destructor (Acari: Varroidae)

“…Regarding to autumn assay, the average NFM in Apivar colonies was reduced a 17.9%, meanwhile in Apiguard-treated ones the reduction was higher, a tested. Thymol (2-isopropyl-5-methylphenol) is one of those products of natural origin which have demonstrated to control varroosis both in field and in laboratory conditions (Colombo & Spreafico, 1999;Floris et al, 2004;Akyol & Yeninar, 2008;Gashout & GuzmanNovoa, 2009). Apiguard acts as an efficient miticide with a low risk of residues in bee products and resistance in V. destructor populations (Fries et al, 1991;Floris et al, 2004;Bogdanov, 2006).…”

“…Thymol (2-isopropyl-5-methylphenol) is one of those products of natural origin which have demonstrated to control varroosis both in field and in laboratory conditions (Colombo & Spreafico, 1999;Floris et al, 2004;Akyol & Yeninar, 2008;Gashout & GuzmanNovoa, 2009). Apiguard acts as an efficient miticide with a low risk of residues in bee products and resistance in V. destructor populations (Fries et al, 1991;Floris et al, 2004;Bogdanov, 2006). The aim of the present study was to compare the efficacy of these two commercial products: Apiguard (thymol, essential oil) and Apivar (amitraz, formadimine), during different seasons (spring and autumn-winter) in the Mediterranean climate.…”