The fight against Varroa destructor - honey bee parasite: Integrated Varroa management

Since Varroa destructor invaded Apis mellifera populations in Europe in the seventies, this parasitism has been extensively studied, from control management ta molecular approaches of the host-parasite relationships. Chemical control of the mite was followed by c1assical events of pest management: resistance of the mite ta acaricides and pesticide residues in the wax. These events induced the set-up of biological and technical control measures of the mite. In parallel, the equilibrated parasitism of Apis cerana, a honeybee from East Asia, by Varroa destructor has been extensively studied and compared to the interaction with Apis mellifera in an attempt to understand the mechanisms underlying this host-parasite equilibrium. The knowledge of these mechanisms should have helped sort out selection criteria for Apis meflifera breeding programmes. However, despite efforts to breed Varroa resistant bees, little progress had been made. The basic biology of the mite, including chemical ecology, behavioural studies, population . dynamics and genetics, as weil as molecular responses of the honey bees, have been investigated for more than 25 years producing an impressive amount of scientific Iiterature, making the Varroa - honey bee interaction one of the most extensively studied host - parasite model systems. More recently, some natural honey bee populations have been shown to survive ta mite infestations, opening the way to the concept of integrated Varroa management. These bee populations will be particularly useful for determining the mechanisms of mite resistance in Apis mellifera. In addition, the recent sequencing of the honey bee genome should help us learn more about the molecular responses of the bees to mite parasitism. Comparative studies between resistant and susceptible bees are being developed and should be helpful to identify the genes involved in resistance. ln my talk, 1 will describe the different steps of the applied and fundamental research developed since the mite invaded Europe and conclude with a discussion of possible integrated Varroa management strategies for beekeeping