Immature Varroa Mites?

One of my two hives appears to be developing a Varroa problem so I have started daily monitoring.

Today, for instance, the hive had a natural mite drop of 9 mites. OK, one day's results should not be taken in isolation but the question I have concerns the number of, what appear to be, immature mites. In the attached photo, taken through the eyepiece of my dissecting microscope, shows the 9 mites that dropped, collected together on a piece of white paper. In the bottom right-hand quadrant, there are 3 mites that are almost entirely white. Reference to 'Managing Varroa' suggests these are likely to be immature female mites, which do not survive outside the cell.

With these immature mites making up 33% of the mite drop, the question that arises is "should they be counted as Varroa in determining the level of infestation in a colony?"

When my 7 day moving-average gets to 10mpd, I intend to take appropriate action - probably vaporised Oxalic Acid.

CVB

charlievictorbravo said:

In the attached photo, taken through the eyepiece of my dissecting microscope, shows the 9 mites that dropped, collected together on a piece of white paper. In the bottom right-hand quadrant, there are 3 mites that are almost entirely white. Reference to 'Managing Varroa' suggests these are likely to be immature female mites, which do not survive outside the cell.

With these immature mites making up 33% of the mite drop, the question that arises is "should they be counted as Varroa in determining the level of infestation in a colony?"

When my 7 day moving-average gets to 10mpd, I intend to take appropriate action - probably vaporised Oxalic Acid.

CVB

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They look life female deutonymphs to me.

Its interesting that you should ask this question because it is exactly the same question I asked in March. According the manual, you only count dark adult mites but when I asked the prof who manages the breeding group I am in, he said to count the nymphs too. His reason was that the purpose of the spring natural mite drop is for comparative purposes only (with a soapy water wash of 30-50g of bees taken from the super at the start of July). He said the spring reading wasn't intended for diagnostic purposes

Vaporise immediately... see if you can knock some more down!


Yeghes da

Lets think here. The mite enering the cell lays how many eggs (look it up). The first is a male which does not survive after the bee pupation stage. Of the female nymphs, after mating, only one or two are mature enough to survive after pupation (you could work this out from two or three angles).

Reading the literature will tell you that more mites will survive from a drone pupation because of the longer time for metamorphosis, but still some still too immature to survive?

That lot, analysed carefully, might give you a clue as to how many cells/new bees might be affected by the varroa. Personally, I would not bother with immature mites; if there are a lot you have, or soon will have, a varroa problem. So keep it simple. The natural drop is of geriatric mature mites which are representative of the typical mite population age spectrum. At this time of the year drone brood culling is a particularly good indicator - keep it simple and choose that as the current assessment criterion is my advice. Complicating beekeeping is not a good way to keep bees.

charlievictorbravo said:

One of my two hives appears to be developing a Varroa problem so I have started daily monitoring.

Today, for instance, the hive had a natural mite drop of 9 mites.
CVB

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http://www.coloss.org/beebook/II/varroa/4/2/4

6. Collect data for 2 weeks, average the figure to obtain mean weekly mite fall.

This period covers natural variation in mite fall due to population dynamics cycles within the host.

NOTE: mites douple themselves in one month., then again douple, and it is 4 times after 2 month.

Finman said:

http://www.coloss.org/beebook/II/varroa/4/2/4

6. Collect data for 2 weeks, average the figure to obtain mean weekly mite fall.

This period covers natural variation in mite fall due to population dynamics cycles within the host.

NOTE: mites douple themselves in one month., then again douple, and it is 4 times after 2 month.

Click to expand...

An interesting phrase from the COLOSS document is "This method is based on the quantification of naturally dead mites" As O90O pointed out, you're looking for geriatric mites that have died and fallen off their perch. Of the 9 mites I counted today, 3 were non-viable immature female deutonymphs so should not be counted and 2 were very much alive.

So, of the 9 mites in the photo in my earlier post, only 4 should be used in in any calculation to arrive at a Natural Daily Mite-Drop in Figure 54 of Managing Varroa or the calculation for weekly mite drop in the COLOSS document.

Although drone culling may be more accurate, it is, nevertheless, quite invasive whereas natural drop monitoring does not disturb the bees at all. I would use it for routine monitoring and use sugar rolling for confirmation at critical stages

It therefore seems that the simple rules for counting mites are:

1. the Varroa mites must have been viable - not immature deutonymphs
2. the mites must be dead of natural causes - not dead because they have been chewed by the bees or still alive because they've been knocked off by some means.

Is this correct?

CVB

charlievictorbravo said:

It therefore seems that the simple rules for counting mites are:

1. the Varroa mites must have been viable - not immature deutonymphs
2. the mites must be dead of natural causes - not dead because they have been chewed by the bees or still alive because they've been knocked off by some means.

Is this correct?

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Yes.
Personally, I think a chewed carapace is a good sign because the bees are dealing with them. Thats a characteristic we should be looking for. Having said that, I was told to include nymphs and chewed carapaces in my mite count in March - it seems to over-state the count to me but hey-ho you do what you're told to do sometimes. I can accept that if its to ensure a standard approach

B+. said:

Yes.
Personally, I think a chewed carapace is a good sign because the bees are dealing with them. Thats a characteristic we should be looking for. Having said that, I was told to include nymphs and chewed carapaces in my mite count in March - it seems to over-state the count to me but hey-ho you do what you're told to do sometimes. I can accept that if its to ensure a standard approach

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I side with o90o. keep it simple. chewed up, alive, immature does not matter. if the total drop gets too high, you have a mite problem and you should do something about it.

.
Very simple method is, that when you break drone cells and you see mites in several cells, you have a mite probkem which becomes douple every month.

thenovice said:

I side with o90o. keep it simple. chewed up, alive, immature does not matter. if the total drop gets too high, you have a mite problem and you should do something about it.

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Thank you for your advice but, if you'd read any of my posts, you'd realise that I am doing something about it.

.
But it is mistake to believe that varroa killing is simple.

Counting mites every day helps nothing. Count brown or white, it does not help the problem.
Mite population douple itself in a month.

Finman said:

.
But it is mistake to believe that varroa killing is simple.

Counting mites every day helps nothing. Count brown or white, it does not help the problem.
Mite population douple itself in a month.

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I agree. We've tried the chemical "solution" and got resistant mites. The answer has to come from breeding bees that are able to cope with varroa themselves. That is why I said that mites with a chewed carapace was noteworthy. Unless you look, you have no idea what is happening. Don't you agree?

B+. said:

I agree. We've tried the chemical "solution" and got resistant mites. The answer has to come from breeding bees that are able to cope with varroa themselves. That is why I said that mites with a chewed carapace was noteworthy. Unless you look, you have no idea what is happening. Don't you agree?

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That job has been done 20 years. It is not easy, as everyone can see.
Mite is able to evolute too, and quickly.

One funny thing in breeding.

Some let the varroa kill his bees and hope that resistant colonies stay alive.

Some look,
1) in which colonies bees resist varroa and
2)in which varroa is going to kill the colony

In cases 2) you can save the colonies with chemicals, when you see that varroa will kill them. No need to sacrifice them for good purpose.


Let them be method is like men in machine gun fire in I world war.

B+. said:

We've tried the chemical "solution" and got resistant mites.

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Oxalic and formic are chemicals, yet no resistance is expected.

boca said:

Oxalic and formic are chemicals, yet no resistance is expected.

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Forgive me: I meant "hard" chemicals. I should have been more precise but I thought everyone would understand my meaning

Finman said:

That job has been done 20 years. It is not easy, as everyone can see.
Mite is able to evolute too, and quickly.

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By "done", I assume that you mean its been worked on for a long time. We didn't get varroa here until the early 1990's.
I agree. The varroa mite evolves too. This is why we need the bee to be able to cope without our interference (hence my interest in varroa with chewed carapace). Its no use throwing one (hard) chemical after another at them. As a biologist, I would have thought you would have been leading the way Finman

kfhjgfhgc

B+. said:

. As a biologist, I would have thought you would have been leading the way Finman

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There are enough fools on that battlefront in Finland.
I wait that others do the job.

Finman said:

kfhjgfhgc

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I'm not sure what this means. Is it Finnish?

B+. said:

I'm not sure what this means. Is it Finnish?

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No, he won't answer with anything sensible ... you are just flogging a dead horse ... He will only trot out his usual intransigent stance 'bees will die' ....