Mite counts

1871 Views 6 Replies 4 Participants Last post by Michael Bush, Sep 7, 2004

Hillbillynursery

Discussion Starter · Sep 4, 2004

Hives are on a screened bottom board(well I move the ones I have around). At what number per 24 hours do you feel they need to be treated?
One hive I put the sceen under today had a foundationless frame that I broke(was not attatched to the end bars or bottom yet). I broke open the drone brood and was finding 2 to 4 mites per cell. When I broke the worker cells open I did not find any mites. Just seeing all those mites in the drone brood made me want to treat. Seeing those tiny reddish brown dots on the white drone larva was an amzing sight. It surprised me how easy they were to see in capped brood. I have my evaporator made and waiting.

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Michael Bush

· #2 · Sep 5, 2004

Personally, if I found 2 to 4 mites in EVERY drone cell, I'd probably use the oxalic acid now and again in five days and then again when brood rearing stops. The first two will knock them back pretty good and the when brood rearing stops you can finish them off.

I wouldn't be surprised to find 2 to 4 mites in a FEW drones cells.

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Hillbillynursery

Discussion Starter · #3 · Sep 5, 2004

What is the key number for a 2 to 3 medium box hive to drop per day on a screened bottom board? As this would give a better over view of the colony. I checked it this morning about 20 hours from installing it. I found 64 mites. I know they are atracted to drone brood and thought that maybe part of the reason I saw so many.

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Michael Bush

· #4 · Sep 5, 2004

64 is a bit high for 20 hours.

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Axtmann

· #5 · Sep 6, 2004

With a natural mite drop of 64 in 20 hours in my opinion the colony has at least 4000 4500 mites, probably more than 5000.
This will double after the next 20 days and without a treatment there is no survivor for the next year.

You can do what ever you think is good for you bees but I would vaporize the hive immediately at least 3 times 4-5 days apart. Its not a big deal; it takes only a minute per treatment and save the live of you bees.

In November or beginning of December I would do the same treatment again.

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Dave W

· #6 · Sep 7, 2004

Greetings Hillbillynursery,
>At what number per 24 hours do you feel they need to be treated?

I dont think anyone knows the answer

Here are some "threshold" numbers I have collect for "Natural Drop".

1) Unassisted 24 hr drop - 60 to 190 [BC, 1/03, p41]
2) Varroa count of 20, treat [ABJ,10/03,p799]
3) Over 50, treat [Beekeepers Handbook, Sammataro&Avitable, p142]
4) 60 or more, treat [Hive Management, Bonny, p2]
5) 59 to 187 [http://www.ent.uga.edu/bees/Disorders/Varroa_mites.htm - Accessed 6/25/04
6) 100+ treat ASAP [Brushy Mtn Catalog,2003,p38] and http://nanaimo.ark.com/~varipm.htm]
7) Sep to Dec - 7 mites [http://www.irishbeekeeping.ie/v2.htm]
8) Keep below 8 to 10 natural drop [MiteGone Brochure,Jan1,04
9) 40 to 150 = Medium infestation [ABJ,5/04,p389]

Examination of Brood is just as confusing!
1) If mites are detected, treat [http://www.ent.uga.edu/bees/Disorders/Varroa_mites.htm]
2) Five mites per 100 pupae, treat [Beekeepers Handbook, S&A, p141]
3) 2 or more on a single pupa indicates heavy infestation [Beekeeping for Dummies, p179 and Beekeepers Handbook, p141]

Somehow, I hope this helps????

------------------
Dave W . . .

Hobbyist - 1 Hive
First Package - Apr 03
Broodnest - 3 Deeps
Screened Bottom Board
Apistan - Aug 18, 03
Grease Patties - All year
2003/04 Winter Loss - 0%
See Forum1/HTML/001304, for ongoing mite counts.

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Michael Bush

· #7 · Sep 7, 2004

I think the problem is that there are many variables involved.

The time of year.

The strength of the hive. (number of bees in the hive)

The temperature.

The TREND of the numbers.

The time of year. There are always more mites in the fall. SOME more mites is normal. A huge amount more mites can be devastating.

The strength of the hive. Obviously if you have three frames of bees and you have 30 mites drop in 24 hours it doesn't mean the same thing as having a 24 hour drop of 30 mites on a booming hive with 7 boxes full of bees.

The temperature. The research I've seen says you get more drop on hot days than cool days. I know it's supposedly the same temperature in the hive, but I'm just repeating what has been observed in the research. You will get a signifcant amount more mites dropping on a hot day than a cool day.

The trend of the numbers is important. As fall approaches and the number of bees is declining if the number of mites falling is growing exponentially (like 40 a day during one week, 80 the next week , 160 the next week) then you have a serious problem. On the other hand if the numbers are staying consistent even though the number of bees is declining, then maybe it's under control. Remember the mites NEED to fall to die or be gotten rid of. So while mites falling does indicate the level of infestation, it also indicates that the mites are dying or being groomed off. If the number is staying constant or dropping then it may just mean the bees are taking care of them. If the numbers are exploading, then you have a serious problem.

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