Requeening ANY colony that has a lot of foraging age bees can be a problem
and a new queen is killed. Requeening in the ABSENCE of a nectar flow is
also a difficult
problem.
However, installing as new queen, Russian or any other European mellifera, is
almost 100% successful when the new queen is installed in a colony of all
nurse bees with open brood and during a nectar flow enhanced with 1:1sugar
syrup.
I hope I have helped.
George Imirie
Certified EAS Master Beekeeper
Beginning my 70th year of beekeeping in Maryland
Author of George's PINK PAGES