Varroa mite count, advise please.

[Van, Arkansas, USA]

My question is how many mites are common to a honey bee hive, 100's or 1,000's.

I treated 18 hives with oxalic acid (OA) sublimation with screened botttom boards, last Thursday, 11/16/17.  Today, Sunday, 11/19, I checked for mite drop.  One hive, B17 had zero mite drop, another hive SqcA17 (split queen cell from A16) had 4 mites, the rest of the hives had between 20 to 150 mites drop.  This is my second treatment with OA, the previous treatment was last September 3rd.

Of course I'm looking at B17 and sqcA17 for queen production in 2018, but that is another story.  What are high mite drops, in the thousands, or in the hundreds for double 10 frame.

Have you ever heard of or seen a hive with thousands of mites in a single hive?  Due to proliferation of mites, 20 mites causes me concern, in the spring time anyway.
Blessings

[tjc1]

Oh, yeah! here are the mite drops for the three sequential weeks of OAV that I did in August/September for my two hives (total drop each week over the first three days after treatment):

Hive 1 - 130, 275, 250
Hive 2 - 250, 825, 700

And yes, I was pretty shocked by those numbers for Hive 2 - So far they seem fine, and I will do one last broodless treatment this week.

[iddee]

Mite drop is not a good indicator. A sugar roll will be much more accurate as to how many mites a  hive has.

https://pollinators.msu.edu/resources/beekeepers/varroa-mite-monitoring1/

[little john]

Van - if you haven't already done so - suggest strongly that you download and watch:

Code: [Select]

http://www.ssyoutube.com/watch?v=q4WvPNmS7uc
I very much agree with Iddee.  A mite-drop only shows the number of dead mites following a treatment from which inferences may then be drawn regarding current status, but always based on past-tense information - whereas a roll will provide a more certain indicator of current infestation status.
LJ

[AR Beekeeper]

Untreated colonies will have mite populations in the thousands, but the natural mite fall counts will vary depending on the amount of sealed brood in the colony.

The recommendation in Arkansas for treating based on natural mite fall is to treat when the fall numbers are 50 per day or above.  Colonies vary in the number of mites they can support and not crash.  This must be learned by counting natural mite fall averages each month and noting the effect on the colony, when PMS begins, and when the adults begin to have that "shabby bag woman" appearance.

I have had colonies that would overwinter after having daily natural mite falls of 120s, but they did not prosper the following year.  Usually if the daily fall in August was between 50 to 120 I would say treatment is necessary.  If you don't worry about winter losses, and don't care about honey production, you can play with your colonies and find their threshold numbers.  The problem often is not finding queen lines that carry high mite loads, but keeping that line.

As for mite numbers, I once treated a hive in September with check-mite and had easily over 10,000 mites fall, and the colony survived the winter and made an average honey crop.  I did not count the mites because I could see no white areas on the sticky board, it was solid mites.

[Acebird]

I don't treat so the only thing I have ever seen is natural mite fall.  I also don't check every day.  It might be weeks between checking the tray.  If a colony is experiencing a broodless period I would expect a greater mite fall so no matter how you do it there could be variations.  To me what matters is how many mites are in the brood.  So why not pull a frame and open up cap brood and get an average that way.  Wouldn't that be more accurate?

[Van, Arkansas, USA]

Thanks for the replies, everyone!   Answered my questions.

Ace, good idea,,  I carry tweezers in my bee suit just for checking capped drone brood.  One July I found zero mites in capped drone brood.  One month later in August, I counted as many as 6 adult females in a single capped drone brood cell, same hive.  Every drone cell I checked had mites in August.
Blessings

[tjc1]

Did my broodless pre-winter OAV  this week. Three day drop was ca 475 for hive 1 and ca 850 for hive 2, FWIW.

[Van, Arkansas, USA]

TJC thanks for the information.  Hive 1 is the hive I would queen from, all thing being equal.

I have 2 hives with 4 or less mite drop, ( hygenic to me),,  4 hives with 20 mites or less,   12 hives had 100?s of mite drop after OA sublimation.  Counting mites 2 days and 5 days after treatment.  I bet you can figure which hives I am going to queen from.  One of my hygenic hives also happens to be my best honey producer, also the bees stay on comb when inspected and are calm honey bees.

Gentle Bees:
I had family over for Thanksgiving.  I opened one hive, no protection, not even gloves, showed my nephews the queen after I slowly pulled a frame out, temps 60?s and sunny, barometer rising.  My nephew, not knowing better, moved his hand across across the frames very fast to point out the queen.  He did NOT get stung.  Nobody, had protection and stood close to the hive.  This is my gentlest hive.  Unfortunately, the hive had to many mites to consider for queen reproduction in 2018.
Blessings

[tjc1]

Hi Van,

That's a pretty laid-back hive for sure!

When you say that you will queen from a certain hive, do you mean that you will use that hive to raise replacement queens for other hives, or for splits? How do you go about that?

Ted

[BeeMaster2]

He means that he will use the queen that has the traits he wants to lay the eggs/larvae that he will use to make it the queens. He can use bees from any hive to raise the queens.
Jim

[tjc1]

Did my broodless pre-winter OAV  this week. Three day drop was ca 475 for hive 1 and ca 850 for hive 2, FWIW.

Checked bottom board for any further mite drop from the Nov. 20 oav treatment and found:

Hive 1 - additional 500 mites
Hive 2 - additional 600 mites