Varroa Alert

[elainemary]

Try a rolling Demaree for that.

hi, tried that for the first time last year & ended up with 3 double brood boxes on one hive but still swarmed! Admittedly only on that hive, queen v prolific. Tried it again but on one of my favourite colonies and got 2 really nice 'supercedure' type cells in the top box, which I made up into Nucs. Both produced really nice queens, one of which I reunited with the parent colony and got a fab heather honey crop from. Will def try again & thought I'd try double brood as well. Always keen to try new ideas!

 

[drex]

Just checked my varroa trays about 10 days after my single OAV. A very low drop ( I do not bother counting). They had thymol in Autumn. Well pleased. They appear all be on 3-4 frames. No brood cap pings seen in the rubbish

 

[GuyNir]

Try a rolling Demaree for that.

Dani, how long are you rolling the Demaree? Until the main flow starts?

 

[Erichalfbee]

Dani, how long are you rolling the Demaree? Until the main flow starts?

I try to start in early April and run till end of June. It depends on colony strength. So yes before Bramble. But I have been caught out and ended up with 6 supers and a 14x12 full of honey.

 

[pargyle]

I try to start in early April and run till end of June. It depends on colony strength. So yes before Bramble. But I have been caught out and ended up with 6 supers and a 14x12 full of honey.

LOL ... Nice problem to have to overcome though !!

 

[Gilberdyke John]

CUT
Oxalic acid is only effective for 3 days after sublimation by bees walking it around and thereafter effects much reduced. So WHAT CUT

can anyone quote a source for the 3 days assumption?

 

[charlievictorbravo]

can anyone quote a source for the 3 days assumption?

Not exactly but in the 2014 research , they monitored the drop every two days after the Initial (only) OA sublimation. This is shown in Figure 1 of the research report as a graph. It showed a peak of about 230 mites dropped at two days, a further 120(ish) after a further two days and maybe a further 10 mites at six days so, based on that, I would have gone for a figure between 2 and six days.

I'm not convinced that OA is spread "by bees walking it around". It lands on every surface in the hive but mites don't walk on the comb - they walk on bees so the question should be "how long before all of the OA microcrystals fall, or are brushed, off the bees?". The mites would probably only encounter the OA when they change host and Al Toufailia touches on this when he states "There are currently no data on how frequently phoretic mites change their host bee in broodless colonies" This is critical research now that we know how much damage "phoretic" mites do to adult bees.

With the benefit of hindsight, it would have produced useful data to monitor the treatment mite drop on a daily basis rather than every two days - we would have had some peer reviewed research that showed the period over which an OA vaporization is effective or has killed all the mites that it's going to kill. I would have liked them to have looked at the dead mites and found out why or how they died - the researchers are insect experts after all.

CVB

 

[pargyle]

With the benefit of hindsight, it would have produced useful data to monitor the treatment mite drop on a daily basis rather than every two days - we would have had some peer reviewed research that showed the period over which an OA vaporization is effective or has killed all the mites that it's going to kill. I would have liked them to have looked at the dead mites and found out why or how they died - the researchers are insect experts after all.

CVB

Yes .. that would be a nice to have but... as was said earlier ... we beekeepers are usually ahead of the science and the treatment works ... at some point a navel gazer will explain to us why ... let's be grateful there is hope that OA is a bronze bullet if not yet a silver one !

 

[elainemary]

can anyone quote a source for the 3 days assumption?
[/

Not exactly but in the 2014 research , they monitored the drop every two days after the Initial (only) OA sublimation. This is shown in Figure 1 of the research report as a graph. It showed a peak of about 230 mites dropped at two days, a further 120(ish) after a further two days and maybe a further 10 mites at six days so, based on that, I would have gone for a figure between 2 and six days.

I'm not convinced that OA is spread "by bees walking it around". It lands on every surface in the hive but mites don't walk on the comb - they walk on bees so the question should be "how long before all of the OA microcrystals fall, or are brushed, off the bees?". The mites would probably only encounter the OA when they change host and Al Toufailia touches on this when he states "There are currently no data on how frequently phoretic mites change their host bee in broodless colonies" This is critical research now that we know how much damage "phoretic" mites do to adult bees.

With the benefit of hindsight, it would have produced useful data to monitor the treatment mite drop on a daily basis rather than every two days - we would have had some peer reviewed research that showed the period over which an OA vaporization is effective or has killed all the mites that it's going to kill. I would have liked them to have looked at the dead mites and found out why or how they died - the researchers are insect experts after all.

CVB

Regarding bees don’t walk around on the comb - do you mean when in cluster? Could see my bees walking around after the sublimation through the glass crownboard so could imagine that may help transfer sublimate to a small degree. Think the point about it landing on every surface may depend on whether you use a passive sublimation eg pan device or a Sublimox. Key reason why I will buy a Sublimox for next season, pushes the gas out more effectively and covers all the surfaces. Suspect the cheaper pan devices esp if vaporising under an OMF and with more than one box, may struggle to coat every surface. Perhaps this helps explain why 2 vaps are more effective than one in broodless colonies

Re John’s question on a source of 3 day effectiveness of oxalic acid, haven’t picked this up from peer reviewed research but from beekeeper experience.

Reading Al Toufailia’s doctorate thesis it struck me he went a bit ‘off piste’ from his original objective of varroa IPM. Whilst he covered oxalic treatments in broodless colonies, drone brood removal effectiveness and hygienic bees, he went off at a tangent looking at hygenic stingless bees and small hive beetle in Brazil. Would have been better to focus on other ways of using oxalic eg in colonies with brood. Time may have been an issue but he does conclude multiple doses and other ways of using was an opportunity for further research

 

[charlievictorbravo]

Regarding bees don’t walk around on the comb - do you mean when in cluster? Could see my bees walking around after the sublimation through the glass crownboard so could imagine that may help transfer sublimate to a small degree.

Perhaps I did not make myself as clear as I might have done. The paper was suggesting that OA was spread around the hive by bees walking around. I was pointing out that I thought mites don't walk on the comb - they walk on bees so to get the OA onto the soft footpads or mouthparts of the mites requires them to pick up the OA from the bees before it is brushed or groomed off. I don't think that bees walking around the hive spread much OA that would be in a place to kill mites, except of course that in walking on other bees, the "walker" transfers OA from its feet to the body of the "walkee".

If they had monitored the mite drop daily rather than every two days, they, and we, might have understood for how long OA remains effective. So many missed opportunities associated with this research.

CVB

 

[Amari]

With the benefit of hindsight, it would have produced useful data to monitor the treatment mite drop on a daily basis rather than every two days - we would have had some peer reviewed research that showed the period over which an OA vaporization is effective or has killed all the mites that it's going to kill. I would have liked them to have looked at the dead mites and found out why or how they died - the researchers are insect experts after all.
CVB

Ah, but mites are not insects....

 

[jenkinsbrynmair]

Think the point about it landing on every surface may depend on whether you use a passive sublimation eg pan device or a Sublimox. Key reason why I will buy a Sublimox for next season, pushes the gas out more effectively and covers all the surfaces.

And you think a varrox doesn't do that? I'd like to see your evidence - if you have any that is

 

[pargyle]

And you think a varrox doesn't do that? I'd like to see your evidence - if you have any that is

The pan type evaporators are just as efficient at sublimation .. even when used under a mesh floor the entire inisde of the hive and frames get covered in sublimate. They are a cheap and effective method of sublimating OA ... adaptions to fit most types of hive can be made. Downside is you need to carry a battery around or have some means of creating a 12 volt supply, I have a spare 12 volt battery mounted on the frame of an old shopping trolley (useful when someone's car batter goes flat as well !).

 

[Ringlander]

Hello everyone, I thought the attached graph would be of interest. Following on from my early post on page 1 of this thread I recorded the 24 hour mite drop on each of my three hives after vaping with Api-Bioxal to see how the drops changed with time. The OA was introduced using a simple sublimation pan, 2.3 g of crystals each time with the 14x12 hives closed and with boards beneath the open mesh floors. All three hives are Maisemore polys and all have a nadired super under the brood box and a half height super on top as an eke to allow space for fondant. There were three applications on each hive, on days 1, 9 and 16, so on the graph the day 1 figures represent the natural drop occuring before the treatment was applied and the spikes can bne seen to be the day after each treatment. The pre-treatment natural mite drop had been gradually increasing since all three hives were treated with MAQS in September. The weather here in Norfolk during the treatment has been between 0 and 8 deg C and pretty wet and although there has been a little activity on warmer days the bees are pretty dormant. The vertical graph axis shows the number of mites counted on the board and the horizontal the days from the start of treatment.


What I find interesting is the way the mite counts drop over 8 days for the first application, maybe 4 days for the second and 3 for the third. Whether this is a consequence of the number of mites in the hives, the density of the bees cluster, external effects such as weather or something else I couldn't say, but I think it suggests that streatment schedules might be better based on mite counts rather than a fixed 3 day, 5 day or whatever routine. I appreciate this may not be possible for all beekeepers, but it's worth considering?

 

[gmonag]

Good data.
However,you have to be careful how you interpret them. I suspect that OA is very quick-acting and so most mites wil be killed and drop in the first day after treatment. These data will depend on the number of "phoretic" mites in the hive at that time. The lower numbers in the subsequent days may be a combination of those that took more time to be exposed to the OA and those just emerging from cells after reproduction, both foundress and offspring. Those data will depend on the amount of capped brood present.
The schedule of treatments (when brood is present) should be driven by the varroa reproductive cycle, not the total numbers in the hive.

 

[madasafish]

Perhaps I did not make myself as clear as I might have done. The paper was suggesting that OA was spread around the hive by bees walking around. I was pointing out that I thought mites don't walk on the comb - they walk on bees so to get the OA onto the soft footpads or mouthparts of the mites requires them to pick up the OA from the bees before it is brushed or groomed off. I don't think that bees walking around the hive spread much OA that would be in a place to kill mites, except of course that in walking on other bees, the "walker" transfers OA from its feet to the body of the "walkee".

If they had monitored the mite drop daily rather than every two days, they, and we, might have understood for how long OA remains effective. So many missed opportunities associated with this research.

CVB

Mites have to walk on comb to enter about to be capped cells and lay their eggs.

And I have seen mites walking on combs.(only twice but I have seen it)

 

[Swarm]

BMH has a video on youtube that shows varroa (heavily infested) walking around the comb

 

[elainemary]

And you think a varrox doesn't do that? I'd like to see your evidence - if you have any that is

Personal opinion from observing my cheap pan vaporiser and looking through the crownboards of hives when in use. Would imagine a Varrox is more effective but Sublimox the best due to the pressure of the gas.

 

[elainemary]

Perhaps I did not make myself as clear as I might have done. The paper was suggesting that OA was spread around the hive by bees walking around. I was pointing out that I thought mites don't walk on the comb - they walk on bees so to get the OA onto the soft footpads or mouthparts of the mites requires them to pick up the OA from the bees before it is brushed or groomed off. I don't think that bees walking around the hive spread much OA that would be in a place to kill mites, except of course that in walking on other bees, the "walker" transfers OA from its feet to the body of the "walkee".

If they had monitored the mite drop daily rather than every two days, they, and we, might have understood for how long OA remains effective. So many missed opportunities associated with this research.

CVB

Have you seen this thread from a while ago on the forum? With conclusions on monitoring mite drop after various vaping incidents, concluding most drop in first 48 hours. Also mentioned on the Apiarist website, link below

https://beekeepingforum.co.uk/threads/oxalic-acid-sublimation-frequency.31813/page-2#post-446328
https://www.theapiarist.org/sublimox/

 

[elainemary]

Hello everyone, I thought the attached graph would be of interest. Following on from my early post on page 1 of this thread I recorded the 24 hour mite drop on each of my three hives after vaping with Api-Bioxal to see how the drops changed with time. The OA was introduced using a simple sublimation pan, 2.3 g of crystals each time with the 14x12 hives closed and with boards beneath the open mesh floors. All three hives are Maisemore polys and all have a nadired super under the brood box and a half height super on top as an eke to allow space for fondant. There were three applications on each hive, on days 1, 9 and 16, so on the graph the day 1 figures represent the natural drop occuring before the treatment was applied and the spikes can bne seen to be the day after each treatment. The pre-treatment natural mite drop had been gradually increasing since all three hives were treated with MAQS in September. The weather here in Norfolk during the treatment has been between 0 and 8 deg C and pretty wet and although there has been a little activity on warmer days the bees are pretty dormant. The vertical graph axis shows the number of mites counted on the board and the horizontal the days from the start of treatment.

View attachment 23675
What I find interesting is the way the mite counts drop over 8 days for the first application, maybe 4 days for the second and 3 for the third. Whether this is a consequence of the number of mites in the hives, the density of the bees cluster, external effects such as weather or something else I couldn't say, but I think it suggests that streatment schedules might be better based on mite counts rather than a fixed 3 day, 5 day or whatever routine. I appreciate this may not be possible for all beekeepers, but it's worth considering?

Thanks for sharing this, shows the majority of mites drop 48h after treatment in line with Hivemakers observations (link on a separate post a few mins ago on this thread)