Fluvalinate content of Apistan strips during treatment and efficacy in colonies containing sealed worker brood

Over the last few years, s o m e studies w e r e carried out in Sardinia (Italy) o n improv- ing varroosis management in colonies containing sealed worker brood using Apistan. The fluvalinate content in plastic strips remained almost constant during the 10 weeks of treatment. No significant differences between initial (11.5 + 0.6%) and terminal (10.7 + 0.3%) fluvalinate con- centrationwere observed,indicatingthatremovalbythebeeswas verysmallandtheactiveingredient stripdosagemore thansufficienttocontrolthevarroosis. Apistan application in apiary confirmed an efficacy of over 99%. Most of the mite mortality (> 97%) occurred during the first 4 weeks.