Coumaphos
Behandlungsmittel
Coumaphos is an organophosphate and was commonly used in Varroa control for many years, in Germany mainly in the form of a trickle treatment.
Coumaphos is an organophosphate and was commonly used in Varroa control for many years, in Germany mainly in the form of a trickle treatment. The active substance inhibits acetylcholinesterase and thereby acts as a nerve poison on the mite. In practice it was used as a final mite treatment in the broodless state.
For present-day beekeeping, the organophosphate substance group is of no practical relevance in Germany. The coumaphos-based product is no longer on the market, and coumaphos no longer appears in the current overviews of approved varroacides from the bee institutes. Anyone treating today works with organic acids, with thymol, or, as an emergency option, with amitraz or flumethrin.
The main reason for its loss of relevance lies in its residue behavior. Coumaphos is fat-soluble and accumulates in the wax cycle of a beekeeping operation. From the wax, the active substance can pass back into the honey. Added to this is the resistance problem that generally applies to synthetic varroacides: repeated use of the same active substance selects for mite strains that are no longer killed by it.
For practice, what mainly remains is a classification: coumaphos is historically relevant and explains part of the legacy contamination in the wax of some operations, but it is not a product to plan with today. Anyone with old stock of such products in storage should dispose of it as hazardous waste rather than apply it. Whether a medicinal product may be applied always depends on its current authorization and market status; when in doubt, the relevant advisory service or veterinarian can provide information.