Evaluation of the impact of Exomite Pro on Varroa mite (Varroa destructor) populations and honeybee (Apis mellifera) colonies: efficacy, side effects and residues.

In this research, we examined the application of thymol-based powder, directly over the top of the brood frames in colonies with different population in a 2-year study. The efficacy against mites, the side effects on bees and the contamination of honey were studied comparably to thymol-based gel treatment. In one-store colonies, thymol-based powder treatment gave average efficacy 64.5% and did not differ significantly from thymol-based gel treatment (65.4%). The natural mortality in control colonies was 41.4% and the corrected efficacy (E T) during 2 years was 39.4 and 40.9%, respectively. In two-store bee colonies, the application of thymol-based powder on top of each hive body gave higher E T (45,4%) than on top of the double body hive (40.4%), without statistically significant differences. The average concentration of thymol residues in honey 24 days after the application was 368 and 1,119 µg kg(-1) for the honey of colonies treated with thymol-based powder and thymol-base gel, respectively.

New multiresidue method using solid-phase extraction and gas chromatography-micro-electron-capture detection for pesticide residues analysis in royal jelly.

Royal jelly, one of the most important bee products, can be contaminated with pesticide and/or antibiotic residues resulting from treatments applied either inside beehives or in the agricultural environment. A new multiresidue method was developed and validated for analysis of nine pesticides in royal jelly. Solid-phase extraction RP-C(18) cartridges were used for sample purification and isolation of analytes. Final solution was analyzed with GC and micro-electron-capture detection. Four synthetic acaricides used by beekeepers (bromopropylate, coumaphos, malathion and tau-fluvalinate), and moreover one pyrethroid, two organochlorine, and two organophosphate insecticides were tested. Linearity is demonstrated for the range of 0.0025-1mgkg(-1), with correlation coefficients ranging from 0.99991 to 0.99846, depending on the analyte. Overall recovery rates from royal jelly blank samples spiked at five fortification levels ranged from 80.8% (lindane) to 91.3% (ethion), well above the range defined by the SANCO/10232/2006 and EC/675/2002 documents. The limit of quantification was <0.003-0.005 mg kg(-1) depending on the analyte, and the reporting level of the method, defined as the lowest recovery level, was 0.005 mg kg(-1).

Contamination of honey by chemicals applied to protect honeybee combs from wax-moth (Galleria mellonela L.).

Greek honey was monitored during a three-year surveillance program for residues of chemicals used to protect honey-bee combs from wax-moth. A total of 115 samples purchased from stores (commercial samples) and 1060 samples collected from beekeepers (bulk samples) were analysed for 1,4-dichlorobenzene (p-DCB), 1,2-dibromoethane (DBE) and naphthalene. A purge & trap-gas chromatograph-mass spectrometer system was used for the analysis. During the first year of the study, 82.9% of the commercial samples had residues of p-DCB that exceeded the established limit of 10 microg kg(-1), whilst during the second year 53.6% and during the third 30% exceeded the limit. The percentage of beekeepers samples that had more than 10 microg kg(-1) decreased from 46.6 to 34.7% and 39.8% respectively during the three consecutive years of analysis. Only one commercial sample (0.8%) had residues of DBE that exceeded 10 microg kg(-1) during the three years study, while 9.9% of the beekeepers samples exceeded this limit in 2003. This percentage fell to 1.9 and 2.8% during the following years. Naphthalene was found in more commercial samples than in samples from beekeepers during the first year, but decreased to similar levels during the next two years. Honeys that are produced earlier in the season are more contaminated those produced later.