Evaluate the toxic effects of five acaricides on the parasitic mite (Varroa destructor) and
honeybee workers (Apis mellifera L.): Denfer 15% (Spirodiclofen), Kofex 24%
(Spiromesifen), Metake 20% (Amitraz), Koloum super 24% SC (chlorfenapyr), and
Abalon 1.8% (Abamactine). These conventional acaricides are cheap and easy to apply,
but prolonged use causes Varroa mites to rapidly develop resistance, and bee products
can become contaminated with residues of acaricides. The bioassay test was used to
detect acaricides toxic effects. Spirodiclofen and Spiromesifen were the most toxic
compounds to honeybee worker with LC50 values of 0.923 and 1.195 ug/ml, respectively,
after 5 days, but Amitraz, Chlorfenapyr, and Abamactine were the least toxic compounds
to honeybees with LC50 values of 1.752, 42.72, and 56.868 ug/ml, respectively, after 5
days. Amitraz, Spiromesifen and Spirodiclofen were the most toxic compounds on V.
destructor with LC50 values of 0.497, 0.888 and 2.014 ug/ml, respectively, after 4 h, but
Abamactine and chlorfenapyr were the least toxic compounds on V. destructor with LC50
values of 70.972 and 76.62 ug/ml, respectively, after 3 h. Varroa mite infestation rates
decreased in brood (75.5% vs 67%) and adult honeybee workers (77.16% vs 100%) of
colonies treated with Spiromesifen and Amitraz, respectively, when compared to only
non-treated colonies. Detecting residuals of acaricides by HPLC in honey and beeswax
revealed that they were contaminated with Amitraz and Spiromesifen residues, but that
they did not exceed the MRLs established by EPA and European Commission guidelines. |
