Surely it’s 8 or 9 weeks rather than 6 for big improvement

[RogerIvy]

When replacing a queen in a defensive colony we all say you see the improvement in 6 weeks.

When I look at the sequence of events this is how I see it:
Kill the old queen
Wair 7 days, knock down EQCs and introduce new queen
Two weeks (14 days) countdown to when all the old queens cells have brood emerged
Plus six weeks (45 days) to when the vast majority of the old queen’s offspring are dead.

So in a nutshell at least 7 weeks when we begin to notice an improvement after introducing new queen, more likely 8 weeks when we see a big improvement.
Or put another way, 9 weeks from when we kill the old queen.
I know I’m nitpicking one or two weeks, but my personal experience is I breathe a sigh of relief at 8 weeks. I’ve not found a big improvement at 6 weeks.
By that I mean general activity when working around the hive, when you’re working in the hive after a few weeks most of the cranky old foragers are out and the bees in the hive are mostly the offspring of the new queen. We had a big problem with a colony that we had to keep well clear of. They only calmed down after 8 weeks from intro of new queen.

Make sense?

 

[jenkinsbrynmair]

Kill the old queen
Wair 7 days, knock down EQCs and introduce new queen

well that's a week you've wasted - as well as risking compromising the new queen - she needs to be introduced immediately on removing the old one. then she should hopefully be laying within a week or less
you usually witness an immediate slight change in the colony's demeanour.
The flying bees (the biggest troublemakers) will be dying off from day one and the new emerging bees, although not the new queen's progeny will be calmer.

 

[Kaz]

well that's a week you've wasted - as well as risking compromising the new queen - she needs to be introduced immediately on removing the old one. then she should hopefully be laying within a week or less
you usually witness an immediate slight change in the colony's demeanour.
The flying bees (the biggest troublemakers) will be dying off from day one and the new emerging bees, although not the new queen's progeny will be calmer.

Phew, that's a relief. I have a horrible colony I'm requeening by making hopelessly queenless then introducing a frame of young larvae from my loveliest queen. I'm at the awful stage where having been rendered queenless they dont yet have an emerged queen and having harvested a number of the QCs yesterday I was thinking that I couldn't bear another 6-8 weeks of having to deal with them ( and their equally horrible neighbours who have all been moved to an isolation apiary where the marauding thugs can't attack anyone). This is so reassuring, I can't wait for the day when I can get in the van and leave without taking a cloud of bees with me!
Go collect a swarm they said, it'll be fun they said

 

[blackcloud]

The change can be immediate but not necessarily a whole lot better in some instances.The last new nuc I built was stocked from some feral shockers and took the full term to cease the behaviour.
They would be at the van windows before the ignition was turned off.