I

ANNO 2 Numero 3
Antonio Nanetti [1[, Nicolaos Bacandritsos[2], Iosif Papanastasiou[1], Costantinos Saitanis[3], George Th. Papadoulis [4]
Comparison between six thymol based formulations in the control of Varroa destructor (Anderson & Trueman) in Greece

[1] CRA - Istituto Nazionale di Apicoltura, Bologna (Italy)
[2] Institute of Veterinary Research of Athens, National Agricoultural Research Foundation, Athens (Greece)
[3]Laboratory of Ecology and Environmental Sciences, Agricultural University of Athens, Athens (Greece)
[4] Laboratory of Agricoultural Zoology and Entomology, Agricultural University of Athens, Athens (Greece)

Corresponding author: ananetti@inapicoltura.org

The present study was undertaken to evaluate the efficacy of six formulations containing thymol against the varroa mite under real beekeeping conditions of the Attica region, Greece. The treatments were made in the middle of April 2002 in an apiary divided into seven groups of eight colonies, one of which served as a control. To fit the usual beekeeping practice of the area, the colonies were forced to a broodless condition, that was attained by queen caging and was exploited to promote the treatment efficacy.

The following formulations were taken into account:
1) 15 g of thymol crystals in hollow plastic cylinders (3 times at 8-9d interval);
2) 15 g of thymol and 300 microl of clove oil included in gel (twice at 8-9d interval);
3) 15 g of thymol and 2g of vaseline (twice at 13d interval);
4) Api Life Var (3 times at 7-11 d interval);
5) Apiguard (twice at 13 d interval);
6) Thymovar (twice at 20-21 d interval).

Formulations 2 and 3 were prepared on the purposes of the present experiment and had not been taken into previous consideration. Formulations 4, 5 and 6 are commercially available and were bought on the market.
The mite mortality attained the 9.0% in the controls. The commercial formulations yielded high average efficacy, which ranged between 90.4 and 90.6%. Crystal, gel and vaseline formulations killed 91.8, 88.4 and 84.9% of the mites, respectively. The mixture of thymol and vaseline was significantly less effective than the other acaricides.

All the queens survived the caging period, although they were placed rather close to the point of treatment. External observations of treated and control colonies did not put into evidence serious problems with the tolerability. Thymol crystals induced some clear behavioural disturbance, which was temporary and did not seem strong enough to exclude the formulation from the field praxis. Apiguard induced lower disturbance to the colonies if compared to the other commercial acaricides.

The acaricides that were taken into consideration fit the need of practicable, highly effective and fairly tolerable treatments against varroa mites during the warm period of the beekeeping season. The easy and cheap preparation makes the tried non-commercial formulations to deserve further consideration, and opens the perspective to include them into the common beekeeping practice.