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The bees in one of my hives seemed to be moving pretty slow, so I checked them for mites. I found 6 mites, but I was probably just under 300 bees, so I’m guessing my mite count is between 3 and 4 percent. I decided to put in some apiguard. My question is, in early spring what is an acceptable mite count? I’m just starting my second year with bees so I have nothing to gauge it against.
 

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2% is usually considered the threshold for treatment. Remember to test after to determine the effectiveness of the treatment, and keep testing every month. The mite count will jump drastically toward fall so keeping the counts low now will really help later, much easier to manage than have to react when your counts jump.
 

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That's...a lot of mites to have this time of year. Also, when does your nectar flow start? Apiguard has to stay on for 28 to 42 days for full effect and the recommendation is another two weeks before putting on honey supers or you will contaminate it with the thymol. Are you planning on collecting honey this year from the hive you are treating?
 

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Mid May is the start of nectar flow. I would like to collect honey this year. What would be the best plan? Would it be a good idea to use oxalic acid? I did use that last fall when mites got bad.
 

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Formic Acid is what is approved to use with honey supers on, but it is a lot harsher on the bees and is very temperature dependent. Oxalic Acid, which is much easier on the bees will not treat mites in capped cells, so a series of treatments are needed or treat during broodless periods. OA is not approved for use with honey supers on. You can take the supers off to treat then put them back on after some amount of time after treating but that is a lot of labor.

I'm sure there will be plenty of great comments here as well on what to do. In the end you may have to just pull the plug on honey production and focus on getting bees healthy and heavy enough to get through winter.
 

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OA is good but think on this: Just to give you an idea of these mites; when the female enters the cell right before being capped, she lays a minimum of 5+ females which mate with the male mite in there. So think of all that capped brood you have and all the mites emerging from those cells.
 

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Aylett, VA 10-frame double deep Langstroth
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Deb, you might want to recheck your numbers on how many of the female mites reach sexual maturity before the cell is uncapped and the worker, or drone bee emerges. Light colored mites are immature and do not live to reproduce.

Looee, to answer your original question, the only acceptable early spring mite count is zero. If you start now with OAV every three days, you will knock the mite counts down far enough before your flow starts to be safe until this summer. I suspect you did not treat mid winter when the hive was broodless so the mites have a head start this season.
 

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Well if you convert the days into hours; using worker brood, not drone, the cell is capped and the female mite is in there, so 12 days till bee emerges, thats 288 hours (more precise). Within 60 hours the male mite egg layed, (she lays an egg every 30 hours) hatches at 228 hours. Hour 156 male matures, hour 123 first female matures, hour 99 the male mates with the first female. 69 hours 2nd female mates, 39 hours the 3rd female mates, 9 hours the 4th female mates. So drone brood is 3 days longer, more time. That sound correct? I think I meant 5 females including mother mite.
 

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Reproducing Varroa females lay the first egg in the brood cell approximately 70 hours after host cell capping (Ifantidis 1983; Steiner et al. 1994). This egg is unfertilized and develops into a male, while the three to four subsequent eggs that are laid at approximately 30 hour intervals are fertilized and develop into female offspring (Rehm and Ritter 1989; Martin 1994). However, the last eggs laid will usually not reach maturity, because the developmental time of the immature bee in the capped cell is too short to allow completion of mite development. Since the capped stage of drone cells is about two days longer than that of worker cells (Jay 1963), drone cells are in principle more rewarding in terms of mite reproduction than worker cells because more young mites can reach maturity. In the European honey bee, mites produce on average two to three viable female offspring in drone cells and one or two viable female offspring in worker cells (Schulz 1984; Fuchs and Langenbach 1989).
https://www.beeculture.com/a-closer-look-varroa-mite-reproduction/
 

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Discussion Starter #11
Is it safe to use an OA vaporizer multiple times? If I were to do 3 treatments at 5 day intervals, would that kill the mites without killing the bees?
 

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I would do 4 treatments at 5 day intervals.
Then test for mites to see how you're doing.

Also, the most important OAV treatment is mid winter. I usually do an OAV or 2 in late December. Hives here are broodless at that time.

Let the others here get bogged down in discussion of reproduction. You need to focus on mite eradication.
Good luck.
 

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Is it safe to use an OA vaporizer multiple times? If I were to do 3 treatments at 5 day intervals, would that kill the mites without killing the bees?
Oxalic Acid applied with a vaporizer will not kill your bees. You might cook a few, but that is another story.
 

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There are other studies out there, this isnt cut in stone. They can lay that first male up to 60 hours; big difference in hours if she lays that first egg in 30 hours or so. Even looking at Randys findings and averages that indicates some had to have laid at least 4 females and some maybe 2 females, MATED WITH THE MALE, to get some of the averages. I can email Randy and ask him about this, being he and Dr. Bromenshenk work closely together on certain bee studies.
 

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Deb, that would be really cool if you did. I can only go by the studies I have read and the presentations I have seen. If there has been a change in our understanding of the varroa mite reproductive cycle, it would be valuable information to share
 

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JW what do you think has changed? How many times have you opened drone brood and found 3 or more mites?
 

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Not sure. I see the study msl cited was done in the late 80's. We have learned a bit about varroa since then. I did note that Randy indicates that the varroa population doubles every 33 days. That is not consistant with one going in and five coming out every 12 days. But even that paper was written a few years ago. I try to keep an open mind about most things. It is amazing how much more one can learn when one does as science is always evolving.
I am even coming to the realization that the earth is not flat.:)
 

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There are other studies out there
please site one (thats how I learn) showing worker brood averaged mite reproduction is 4+foundress
if they repodused that fast we would see the population doubleing must faster .... 100 mites would be 460 in 16 days instead of the 200 in 33 days we tipicaly see

"A female mite can live for 3-4 breeding cycles. Reproductive success averages roughly 1-2 viable offspring in worker cells, and 2-3 in drone cells. Because of this low rate, in order for the mite population to increase, female mites must invade a cell and reproduce more than once during their lifetimes" http://scientificbeekeeping.com/fighting-varroa-the-silver-bullet-or-brass-knuckles-2/


"Though not generally observed, it has been noted that up to three female mites could survive to adulthood under ideal circumstances (Rehm and Ritter 1989), and some have speculated that up to four fertilized females may mature, based on bee development time (Donze and Guerin 1994)." Roth EtAl (2020) https://academic.oup.com/jipm/article/11/1/1/5692075
there is what is mathematically possible and there is what is normally observed..

How many times have you opened drone brood and found 3 or more mites?
don't confuse mites with viabul mites
 

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So I must be missing something what do you think it is? My class was taught female mites can have 3-8 reproductive cycles, but the average is 3. This is in worker brood. She has 12 days 288 hrs, to reproduce, laying the male within 60 hours, and an egg every 30 hours after that. He matures at hour 156, and at hour 123 first female matures, and at 99 hours they mate.
69 hours 2nd female mates, 39 hours 3rd female mates, 9 hours 4th female mates.
What absolutely kills me is that some of you are dissing a prominent University.
 
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