Effects of synthetic and organic acaricides on honey bee health: a review

The honey bee is a crucial pollinator of agricultural crops and also an economically important producer of commodities such as honey and beeswax that find diverse uses in the food industry, cosmetics and medicine. At present, the ectoparasitic mite Varroa destructor is viewed as the most damaging pest of the honey bee worldwide. Without treatment, colonies generally collapse within a few years. To keep the population of the Varroa mites low, beekeepers relay on the use of synthetic and organic acaricides, the most popular commercially available ones include amitraz, coumaphos, flumethrin, fluvalinate, formic acid, oxalic acid and thymol. 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. Residues of acaricides are present in high concentrations throughout the hive and bees are exposed to them all year around. The present review summarises the current knowledge of the deleterious effects of conventional acaricides on honey bee health. Numerous commercially available acaricides and their active substances have been shown to have negative effects on honey bee brood development, queen and drone reproductive health, learning, longevity and colony strength. Acaricides do not only act alone, but also in synergic combinations to affect bee health. Since some drugs cause substantial weakening of bee colonies, they can make them more susceptible to other diseases such as nosematosis or to extreme climatic events. As wax combs are contaminated with high concentrations of acaricide residues and Varroa mites are chronically exposed to them, the parasite may develop resistance faster. In combination with other stressors, acaricides could be a contributing factor to colony collapses. Key words: synthetic acaricides; varroacides; honey bee; Apis mellifera ; synergy; organic beekeeping VPLIV UMETNIH IN NARAVNIH AKARICIDOV NA ZDRAVJE MEDONOSNIH CEBEL Povzetek: Cebele so pomemben oprasevalec kmetijskih pridelkov in gospodarsko pomemben proizvajalec izdelkov, kot sta med in vosek, ki se uporabljajo v živilski industriji, kozmetiki in medicini. Trenutno je zunanji zajedavec prsica varoja (Varroa destructor) eden najvecjih skodljivcev za cebele v svetu. Brez zdravljenja cebelje družine napadene z varojo vecinoma propadejo v nekaj letih. Za ohranjanje nizke populacije prsic varoj cebelarji uporabljajo umetne in naravne akaricide. Najbolj priljubljeni, komercialno dostopni, so amitraz, kumafos, flumetrin, fluvalinat, mravljincna kislina, oksalna kislina in timol. Ti akaricidi so dokaj poceni in enostavni za uporabo, vendar podaljsana uporaba povzroca hitro razvijanje odpornosti pri prsicah varoja in vecjo možnost onesnaženja cebeljih pridelkov. Ostanki akaricidov so po zdravljenju lahko prisotni v visokih koncentracijah v celotnem panju in so jim cebele izpostavljene celo leto. Po uporabi je tudi satje pogosto onesnaženo z visokimi koncentracijami ostankov akaricidov, ki so jim prsice varoja kronicno izpostavljene in lahko zaradi tega hitreje razvijejo odpornost. Pregledni clanek povzema trenutno znanje o skodljivih ucinkih konvencionalnih akaricidov na zdravje cebel. Dokazano je, da imajo stevilni komercialno dostopni akaricidi in njihove aktivne snovi negativne ucinke na razvoj cebel, vplivajo na razmnoževalno sposobnost cebelje matice in zmanjsujejo sposobnost ucenja cebel ter dolgoživost in moc kolonije. Akaricidi ne delujejo samo kot posamezne ucinkovine, ampak tudi sinergisticno, kar lahko dodatno slabo vpliva na zdravje cebelje družine. Nekatera zdravila lahko povzrocijo znatno oslabitev cebeljih družin, lahko pa jih tudi naredijo bolj dovzetne za druge bolezni, kot je nozemavost, ali bolj obcutljive na slabe vremenske razmere. V kombinaciji z drugimi stresorji lahko akaricidi prispevajo k propadu cebelje družine. Kljucne besede: umetni akaricidi; varoicidi; cebela; Apis mellifera ; sinergija; ekolosko cebelarjenje