OXALIC VAPORIZATION IN COLD WEATHER.

[Apinor]

I am a Norwegian beekeeper who is just about to start with evaporation of oxalic acid and ApiBioxal, both for testings. With us, the outside temperature has reached 0 to minus 3 degrees C. I close the hives completely to obtain the best effect. My question: Can you evaporate the OA/AB by a temperature close to or below 0 degrees and get an acceptable effect? The problem is the bees in a tight cluster. I have read that at low temperatures you can give the cubes two treatments each with 2g OA or AB The first a "wake up" to dissolve the cluster and the second 2g treatment after 15 minutes in an open cluster to kill the varroa. Does anyone practice this in cold weather? I know the InstaVap clogs up with ApiBioxal but other types of equipment works well. Grateful for getting your experiences.

 

[jenkinsbrynmair]

OA doesn't get evaporated with an instavape or any other bit of kit - sublimation is a different process.
the cluster needs to be fairly open for sublimated OA to be effective.
you need outside temperatures of abobe freezing as the bees need to be fairly active in the hive.
Breaking up the cluster in sub zero temperatures is not something I would do or advise.
closing up the hive is a pretty pointless exercise regardless of temperature
I wouldn't touch apibioxial with a bargepole regardless of the equipment I was using

 

[Sutty]

I'd also be concerned about artificially breaking up the cluster in cold weather in case they re-form badly eg in several smaller clusters. I don't know if there is enough heat & disturbance to even break up the cluster with an OA vape.
If you have a visible cluster eg under a clear crownboard please let us know what happens! (Though they should be lower down at the moment). An endoscope might help.

 

[Apinor]

But imagine Norway in November, we treat the hives by dripping OA solution down to -5 degrees and open the hives without problems not loosing a single bee. Cold winters do not kill my Buckfast bees, and normally there are no snow by treatment.
The bees get out of the cluster by dripping and spread out in the hives making stress in the society for 2 weeks from treatment, but as a rule, they do not fly out. But I have no experience doing this by OA sublimation. Therefore my question, do anybody know more about sublimation down to the freezing point?

 

[jenkinsbrynmair]

But imagine Norway in November

I'd rather not

 

[Sutty]

I'd be tempted to make an eke with a clear top you can cover with insulation, sublimate OA into the eke and observe what they do (if you can see a cluster).

 

[Gilberdyke John]

OA doesn't get evaporated with an instavape or any other bit of kit - sublimation is a different process.
the cluster needs to be fairly open for sublimated OA to be effective.
you need outside temperatures of abobe freezing as the bees need to be fairly active in the hive.
Breaking up the cluster in sub zero temperatures is not something I would do or advise.
closing up the hive is a pretty pointless exercise regardless of temperature
I wouldn't touch apibioxial with a bargepole regardless of the equipment I was using

Id hate to blast the cluster with high temperature air/powder stream sufficient to create disturbance. Most likely it'll burn the wings off any bees it impacts

 

[jenkinsbrynmair]

or blow a hole in the cluster

 

[Apinor]

Id hate to blast the cluster with high temperature air/powder stream sufficient to create disturbance. Most likely it'll burn the wings off any bees it impacts

But sublimation of 2g OA is a very little blast, and as soon as it reach the frames from the bottom board, it is cooled down and the crystals have the same temperature as the hive environment. The bees are not heated up at all by the sublimation of OA. But the crystals stress the bees in the same way as the dribbling do.

 

[Gilberdyke John]

But sublimation of 2g OA is a very little blast, and as soon as it reach the frames from the bottom board, it is cooled down and the crystals have the same temperature as the hive environment. The bees are not heated up at all by the sublimation of OA. But the crystals stress the bees in the same way as the dribbling do.

I don't believe you've used a tube discharge type sublimation device from above. It's not something I'd consider employing directly at a tight cluster because it does produce a visible and moving plume of hot gas/particles. However it can deposit a coating of OA on top of the frames which pre clustering is distributed by bee activity. After clustering it's naturally very much slower because of lack of bee movement. The OA is still OA after time so any that is moved around has the same effect on mites.

 

[Apinor]

My InstaVap sublimator spread the OA sublimation from a hole in the bottom board. The crystals become cooled and will be spread in between the frames. Some reports I have read shows sublimation of different quantities like 1,5g, 2,25g and 4g trials to show the different in effects. If 4g is not a threat, I think, what if I use 1g to open the cluster and then after 15 minutes give them 2g as the main treatment. It will probably also work in temperatures close to 0 degrees C. By the way, on Wednesday we get wind and +7 degrees C which will be worth waiting for. I will probably then check the cluster formation and give them a proper treatment in comparison to the cluster formation. I doubt that the treatment using 2g represents any heating that could be harmful. As soon as the particles get inside, the temperature drops in seconds and the vapor turns into micro crystals with a large surface area in relation to its weight. The bees have a "bonnet" on the outside and are well protected against temperature shock. Then we should have been much more concerned about the temperature effect if they are heavily smoked. I have 23 years of experience from OA dripping. With minutes it has always giving a completely break up of the cluster formations. From the OAV I have made, the stress level is fare lower by OAV than by OA dripping. In 1983 I started with beekeeping.