Direct effect of acaricides on pathogen loads and gene expression levels in honey bees Apis mellifera

► Impact of acaricide application on honey bees in a varroa mite-free area was explored. ► Acaricides thymol, coumaphos and formic acid altered some metabolic responses. ► First report of acaricides altering vitellogenin gene expression. ► In-hive acaricide applications can potentially interfere with honey bee health.