Re: OA vape 5 days vs. 7 days apart - what do you recommend?
The following is JHMO. And, I am not making a recommendation, just reporting what I have found and what I consequently do:
1st, I would not treat a hive with any "chemical" with honey supers on. While in some cases it may be okay to do so, there is no need to do so, so why do it? Pull the supers and then hammer the mites. At the very least, I do this for my own peace of mind and as a courtesy to my honey customers. Again, JMHO.
2nd, I have experimented with different amounts of OA when I OAV my hives, and I have found that you can increase the OA dose substantially above the recommended 1g per deep without any noticeable harm to the bees. I've tried as much as 3x the recommended dose and not seen any ill affects to the bees. I am not saying there is any benefit to increasing the dose, just that the bees are relatively insensitive to OA dosage. And, I am not saying there is no upper limit to the dose, just that the standard 1g per deep is a conservative amount. YMMV.
3rd, I have experimented with OAV intervals. I've done 7 day intervals, 5 day intervals, 4 days intervals, and 3 day intervals. I monitor mite fall with a white coroplast "witness" board at the bottom of the hive, checking the number of dead mites every 24 hours. I have found that the mite fall after an OAV treatment peaks at about 12-24 hours after a treatment. The mite fall usually tapers to about zero 3 days after an OAV treatment. I am not saying this is universal, just my own experience.
4th, I have found that if I do a second OAV treatment the third day after an initial OAV treatment, I usually get a very large mite fall, in many cases equal to or larger than the mite fall after the first treatment. I interpret this to mean that the OAV treatment intervals based on the estimated phoretic period is flawed, and there are other things going on that we don't fully understand. So, it is better to base your mite treatment schedule on witnessed effects.
Note that the above treatment info is for the Fall when there are pretty much no drones being produced. Also note that the worker bee larvae are capped for 11-12 days.
Taking the results of the 2nd through 4th points, I OAV every three to four days (depending on my ability to get back to my hives) until I get a very small mite fall after a treatment as determined by monitoring the mite fall. Some hives take 3 treatments, some hives take up to 5 treatments to see that small mite fall.
Treating for mites (I switched over to OA in the EPA-approved packaging when it became available):
Witness board with mites:
An example of tracking mite fall vs treatment interval in new packages. Since these are packages, the number of mites is relatively small:
Last edited by shinbone; 07-25-2019 at 10:27 AM.
(1975-1980, and now since 2011; maintain about 10 hives; Zone 5b; 15" rain; 5500')