Noun
varroa (uncountable)
(beekeeping, chiefly New Zealand) Infestation with the mite Varroa destructor, or the disease caused by such mites.
These bees are resistant to varroa.
The varroa mite nearly wiped out honey bees in the late ‘80s and… Source: Internet
While Bt corn pollen does not kill healthy bees or brood reared on it, Bt pollen reduces the number of bees in hives already weakened by varroa mites. Source: Internet