OAV treatment Temperatures

[BeeMaster2]

What temperatures can you treat your bees with OAV, mainly how low?
Jim

[TheHoneyPump]

Treated some this week.  -1 to +4 deg C. Ambient (30F-40F). The hives I just did are insulated and wrapped. Bees were in calm quiet winter mode, but were active around the entrances.

My gauge of when to do it:  Low enough temperature that all of the bees are in and are loosely clustered. Yet, not so low that they are compacted into a tight cluster struggling to stay warm.
Call it as cool and brisk, not cold and crisp. Look for some activity in the hive but not a lot.

Hope that helps!

[BeeMaster2]

Thanks. Going to do a second treatment now. Not much activity outside the hive. These are the hives I just purchased. The previous owner was treating.
Jim

[sc-bee]

What temperatures can you treat your bees with OAV, mainly how low?
Jim

From the oxavap web page;

What is the outside temperature range to perform OAV?
You need an outside temperature of 37 (f). There is no top temperature. The temperature of 37 f is only needed at time of treatment and 1-2 hours thereafter.

[BeeMaster2]

Thanks SC.
Jim

[blackforest beekeeper]

seems a bit overly accurate to be realistic....

[BeeMaster2]

BFB,
So what are you saying? What is overly accurate? Are you saying that it sounds correct or wrong?
Jim

[blackforest beekeeper]

37 degrees point blank.

[TheHoneyPump]

That is a quote right off of the Dadant OAV information sheet.

Really, in practice the ambient temperature matters not. The importance is the condition of the cluster at the time of applying OAV.
A tightly packed cluster does not allow the vapor to penetrate to the inner bees, which will actually be the ones with the most mites on them.
What you are looking for is active somewhat beezy inside but not out flying. The cluster has to be loose so the vapor gets in amongst all bees and all frames and the bees at a time when the bees are also active enough that they will begin fanning it. Look for busy bees housekeeping rolling in/out around the entrance(s). If you are able to lift the lid and look what you want to see are bees loose across all of the top bars walking around busy working doing bee stuff.  That is ideal condition for OAV.  If you see a dense cluster that isn't doing much, not a good day for OAV, defer for another day.

Applying OAV is best done in the mid afternoon when bees are most active, yet on a day that is so cool or rainy that they are staying inside.

[BeeMaster2]

Thanks THP and BFB.
Jim

[blackforest beekeeper]

My gizmo heats up the box to some point, so they start moving around.

if temps make tight clusters for a long time and OA is needed, dribbling is the thing to do, Id say.

[BeeMaster2]

We rarely have tight clusters here during the day time, especially this time of year. Even right now it is only 44 degrees at 5:45 AM. Tomorrow morning it will bee 30 degrees and then go up to 64 degrees. Our coldest days are usually in January and February. Quite often we have to run the AC on Christmas Day. 😝
Jim

[beepro]

No matter how you treat with OAV they still have mites in the warm winter bee environment.  With flying
weather you can treat during the day time.  That will not stop some foragers carrying the mites on their
return trip from the field.   The most effective method I found is to remove all the cap broods then treat when
they are not in a cluster mode with flying weather. 

[BeeMaster2]

Beepro,
I have read your previous threads stating basically the same thing and it makes no sense to me.
If you remove the capped brood so that you can treat, you cannot return the brood to the hive because if the hive is infected, the brood will also have mites.
Brood is the most valuable item in the hive, especially capped brood because they have already spent 5 days feeding every brood cell.
So now you are removing the next cycle of bees and seriously weakening the hive at a time it is already weakened by the mites.
Doesn?t sound good.
Why not treat the hive once a week for 3 weeks to catch the mites on the bees and as they emerge with the new bees.
Jim

[blackforest beekeeper]

removing the brood and doing OA-treatment is in fact a very good idea. The bees do recover from this soon, if done at the right moment.
Also, you can get all combs out and get all new drawn foundation or even natural comb in a flush. old comb in infested hives tend to be sort of infested, too, with viruses asf.

I guess it all depends on scheduling it to the own climate.

If your alternative is some hard chemical, it might seem like nonsense.

puttting the capped brood back in is nonsense. either the brood frames are melted in or the brood is used differently at another yard, it not infested to bad.

[TheHoneyPump]

( I am assuming when you say pulling brood you mean pulling ALL brood. Else why bother )
Just so folks realize:  when brood is pulled the rotation of the population is halted until the nest is reestablished, rebalanced, and rotating again. The hive will dwindle for a month, dropping off sharply at 2-3 weeks. It will be 5 to 6 weeks until it has a foraging force restored. Expect 8 weeks until it is back to where it was before you messed them up. Pulling brood is a VERY significant setback of the colony. That said, if the brood pulling method is done in your early winter when the hive is not brooding much at all anyways, at that time the impact can be minimized. Pulling brood is a tool to have in your IPM toolbox, my point of stress is that the timing is so important and wanting folks to understand the severity of detrimental impacts so it is not done trivially or haphazardly.

Preferable alternate suggestions you are setup and already using OAV anyways:  To maintain an established colony while thoroughly cleaning up an infestation with zero impact to the balance and functions of the colony; simply apply OAV at 4 day intervals for 24 days.  6 treatments.  To explain that timing please review the brood cycle of egg to cap to bee. A thread here on BM which is a good read with supportive data,  titled:  -Did my first OAV treatment today-

Regarding the temperature question, fyi just yesterday did the last treatment of the year for the backyard hives here.  -1 degC, 30degF
The hives are insulated, sunny day, loose and active clusters.

[blackforest beekeeper]

Hi THP!
Of course I mean ALL brood. In fact, best: all combs. Some bees (if brood used) must go along. I do this (if I do this) for late splits. Some destroy the combs entirely.
And I do this AFTER the last flow. So it doesn`t matter at all for me, the hives will recover just nicely for winter. In spring I have fresh comb and healthy colonies. If I use the brood elsewhere (another yard) they make up nice colonies themselves. I treat them harshly with formic acid, any diseased bees will be dead soon, lots of brood make up for losses. I move the old queens along with the brood (usually) and give a new queen to the leftbehind bees, which will accept her if there is NO brood left just nicely.
It all depends on how long the flow lasts, and how long the after-season for brood-rearing and comb-use will last. constant feeding must be done or looked out for enough flow. Some say, latest is July for us. I do it in August still with good results. But it is not easy to realize the latest time. The bees will have a flow again by beginning of April at the latest and by the time canola really blooms let`s say beginning of May you won`t know the difference to a full colony not having been robbed of the brood.
Some destroy the brood always and say the colonies are better next year.
I would only destroy REALLY infested brood, but I have as yet always had enouhg time to react before that point.

[TheHoneyPump]

BFB, that is a great method of integrating the brood pull in a fall program of re-queening, and splits, and formic treatment to knock off the under cap mites.

My caution note is meant for scenarios of treating a colony that is not intentionally being split up.

[robirot]

Also if we are talking about treating in winter, remember that it is no problem to remove some capped brood.
The brood legt in the hive will carry a lot of mites and be deseased. And the bees are hrading towards a brood stop anyways.

[blackforest beekeeper]

The scientist Liebig and others say, a little brood in winter doesn`t matter mcuh because the mites don`t breed in winter much. He has been wrong before...but....
although temperatures in Germany were not sure for brood-free now, I will treat the next good weather permits.