mite level check

[Brother Dave]

I am wanting to check mite levels by checking drone brood for mites. that way I am not harming my workers. so I have 2 questions.

1.  how many drone makes a sample that will be accurate for my purpose?

2. In that sample size how many mites are an acceptable before treatment is needed?

Thanks

David

[BeeMaster2]

I normally just check the drone brood for mites, especially in the ones that are between boxes and are opened during inspection.
Not sure if it is a good source for a sample because if the mites are only in the drone brood it will not affect your bees.
A normal sample tests the bees. If you do not find them in the drone brood, that is a great indicator that that hive is able to remove them.
Jim

[Vance G]

I would not worry about how much drone brood to check, some folks kill it all and control mites that way.  I would do a sugar roll on a half cup of nurse bees and see how many mites end up in the wetted powdered sugar.  Take the samle of bees off open brood.   

[Gary and Margaret - kiwimana]

Hi,

I think the best way is to do a sugar shake with 300 bees, its more scientific and helps you spot trends in the hives.  The other advantage is that you can do a count on every inspection.  Really handy for Bee Yards that are away from home.

This is how we do it in New Zealand:-

Powdered Sugar Shake – Counting Varroa Mites using icing sugar

[OldMech]

Good Link, but I have a hard time believing there are 300 bees in that little jelly jar, otherwise not a bad method..   I would also recommend treatment at anything over about 6 mites per 300 bees as opposed to ;

The threshold in New Zealand is 40 mites per three hundred bees, the book also states that this threshold may need to adjusted when Deformed Wing Virus is more widespread in New Zealand.

   40?   :shock:   

[Gary and Margaret - kiwimana]

Yep that is 300 bees, that is my hand :)

We use the measure of half a cup of bees.

Yes I agree 40 is crazy, see the table below.  We treat if we get 3 per 300 bees.

Thanks...Gary

[OldMech]

Yep that is 300 bees, that is my hand :)

We use the measure of half a cup of bees.

Yes I agree 40 is crazy, see the table below.  We treat if we get 3 per 300 bees.

Thanks...Gary

 Really? Dang I must be checking about 1000 bees then in my pickle jar... great! Now I have to count them..    :(

[Michael Bush]

>1.  how many drone makes a sample that will be accurate for my purpose?
I would just do a forkful (I would use an uncapping fork) in three or four locations.  The results in one place may not be the same as another.  But also keep in mind they will have to replace the drones you remove and if you hadn't removed them they would have spent those resources raising workers, so it costs you the same as if they were workers...

>2. In that sample size how many mites are an acceptable before treatment is needed?

I don't treat at all.  Ever.  But if I were looking for an economic threshold, I would say if you see an occasional drone with one mite I wouldn't worry about it.  If you see a lot of drones with multiple mites you probably are over the threshold.

When I was counting mites, I would do three things.  Mostly because none of them are 100% reliable.  They are affected by temperatures and other factors that are hard to pinpoint.  Drones can be heavily infested in one location in the hive and not in another.  So if you uncap some drones, do a sugar shake and do a natural drop count, you have some redundancy built in.  Also, I think the TREND is more important than the number.  If the numbers are rapidly growing you have more of an issue than if they are staying steady, no matter what those numbers might be.

[Gary and Margaret - kiwimana]

When I was counting mites, I would do three things.  Mostly because none of them are 100% reliable.  They are affected by temperatures and other factors that are hard to pinpoint.  Drones can be heavily infested in one location in the hive and not in another.  So if you uncap some drones, do a sugar shake and do a natural drop count, you have some redundancy built in.  Also, I think the TREND is more important than the number.  If the numbers are rapidly growing you have more of an issue than if they are staying steady, no matter what those numbers might be.

Great point Michael, always watch the trend not the count.  If you use a computer setup a spreadsheet with a graph, record counts over the year and see when you have a build ups.

Note on graph when you treat (if you do treat) and see if the trend goes down?  Don't wait until you can see mites walking all over the comb.