temperature and O A

[rodmaker]

   Do high temps hinder oa treatments?   Or should i wait until later in the fall our first frost is in November. I am just feeling real good right at this time and want to treat if it won't hurt the girls. This is my annual mite treatment.

[iddee]

What is the temp. if you are using the vapor method? I doubt it is any hotter outside the hive.

[Lburou]

The only temperature limit is to have it warm enough so the bees are not in a cluster (that would protect the mites in the center).  Bees begin to cluster around 57 degrees F, and vaporizer manufacturers recommend outside air temperature above 40 F or above, haven't read an upper limit. HTH   :-)

[LazyBkpr]

From the research I have seen, it is recommended to treat when the bees ARE in cluster because there is little to no, or very little capped brood... 

From Randy Olivers Site;

Does vaporization hurt the bees?

Radetzki didn’t note increased bee mortality after winter treatment. Heinz Kaemmerer of Heilyser Technology Ltd. says: “We treated several colonies for 3 months during winter, once a week with the vaporizer and all colonies survived.” “With brood, colonies can be treated with the right amount of OA 3 to 4 times, a week apart; there is no harm to bees, queen or brood.” Medhat Nasr confirms that vaporized oxalic is very gentle to the bees.
//end

   The transfer rate of the crystals is very high. Dividing a hive in half, treating one side, and then removing the divider showed a 70% transfer rate of the OA crystals and an equal decimation of the mites. So treating while in cluster, I imagine that the crystals will be transferred into the cluster as the bees move in and out... Is it as effective as when treating during warmer weather?  I woulod think so, because there is no capped brood.. but thats just speculation on my part.
   I dont treat when clustered, I do it as Lee says..  Mostly because it still works very well, and I dont have to freeze important parts of my anatomy off to do it, OR disturbn the bees while they are clustered.
   As Iddee said, the temp inside the hive is probably not hotter than outside. if its 100 degrees with the sun shining on the hive they are evaporating water to cool the hive, and they are keeping the hive warm if its cooler than 96 (ish) degrees..  OAV works byu sublimation. The heat turns the crystal into a liquid for JUST a moment, and then it is vaporized.. that vapor turns back into crystals as it cools  so no matter if the temp is 20 degrees or 100 degrees, it should not effect how the OA crystallizes to any extent that would make it either NOT work, or work too well. The only consideration might be, how much capped brood do you have? If its a bunch, treating again after the capped brood emerges (12 days, give or take a day) should catch the mites that were hiding under the cappings when you treated the first time.

  another study;
   Their findings were that beekeepers need only carry this treatment out once a year, because the treatment reduces the number of mites so dramatically that it takes them a long time to build back up.

   Web sites can be found on my site here;
   http://www.outyard.net/treatments.html

    So we have research groups, treating for 12 weeks in a row during winter, and research groups treating ONCE in summer, and both found astonishing results of 97% or more mite kills... With 0 bee mortality....
   So far so good, its "still" looking like the proverbial silver bullet.


   

[rodmaker]

   I was just concerned because the temps are forcast to be102 today and 108 wed and Thur. I know the girls get testy when it gets hot and due to having to fan was concerned about the vapor forcing bees out of the hive so it would not be as effective.

[Les]

Rodmaker....I am concerned about the heat also with the OA.  cannot believe it was a 101 today.  And stupid me worked my hives!

[LazyBkpr]

Thew bees will still return to the hive at some point, but i would think trying to treat while they are bearding would make it difficult and unpleasant. How do you block the entrancement with a rag when there are ten thousand bees hanging out there?
   I would give it some time and treat when it starts to cool down a bit. Save yourself some blood sweat and tears!!

[capt44]

I am treating my hives with oxalic acid vapor this weekend because the temperatures are suppose to be in the low to mid 80's.
I treated in March when the temperatures were in the upper 70's and low 80's and had excellent results.
It's been in the triple digits and to me that's too high.
The bees need to be inside the hive and not bearded outside.

[Lburou]

   I was just concerned because the temps are forcast to be102 today and 108 wed and Thur. I know the girls get testy when it gets hot and due to having to fan was concerned about the vapor forcing bees out of the hive so it would not be as effective.

I've held off for the same reason.   This weekend is forecast to be in the 80's.   I would consider a treatment now a knockdown treatment.  Broodless periods are most effective for lowest overall mite numbers.  :-)

I've had some bees go broodless in the heat of summer, but haven't yet tried OAV then.

[apisbees]

you could treat in the late evening once the bees have quite flying and entered the hive or in the early morning before they start flying. Treating in the middle of the day when the foragers ore out and bees are hanging outside of the hive will cause you to miss killing any mites that are on these bees waiting to develop before entering the cells.

[capt44]

I treat and then re-treat in 10 days.
I read that I can treat when the temperatures are 5 degrees above freezing to 5 degrees below 100 degrees F.

[LazyBkpr]

What Capt said..    In the studies done they treated half a hive with a divider board, then removed the divider and 75% of the mites on the untreated side were still killed because of the high transfer of the OA crystals, which, is part of the reason I teat more than once. To me, its about treating at an acceptable time that makes ME happy...   Granted, I wouldnt do it if they were bearding.