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JayBee

NZBF varroa sampling

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Hi - I'm hoping this isn't too much of a silly question ...

 

I have recently been reading about sampling hives for Varroa (sugar-shake / alcohol or soap wash), and I'm a little bit confused (not unusual for me).

 

I understand that it's important to control Varroa before the mites reach levels that threaten colony production and survival, but wouldn't carrying out seasonal Varroa control treatments following the calendar be just as effective? I presume that mites are always going to be present in the hive, so therefore sampling would just be confirming something I already know (I do realise it is a totally different story if you are using organic miticides and want to determine their effectiveness).

 

I'm definitely not opposed to sampling my hives for Varroa, but I'm just wanting to get a bit more depth of understanding behind why I should be doing it. I would also be keen to know when and how often to sample. Thanks for your help!

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When treating by the calendar you might use sampling to determine whether the treatment has worked. Typically you would sample before and after treatment.

 

If you use an IPM approach you would sample regularly to monitor mite load and apply a range of treatments as and when certain thresholds are reached.

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wouldn't carrying out seasonal Varroa control treatments following the calendar be just as effective?

Not necessarily. Treatments don't always work as planned. One reason (in your northern area) is increasing resistance of mites to Bayvarol at least. Commercials with lots of hives who expect a few hive losses every year are likely to rely on treating by the calendar. Smaller beeks or hobbyists may have more time and or greater allergy to hive losses and are likely to monitor mite levels to determine treatment requirements.

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knowing whats going on in the hive is the mosts important thing in keeping bees varoa are nasty little ######s and can do a lot of damage in a short amount of time knowing what there numbers are gives you a good idea when to treat it no use treating if numbers are low

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When treating by the calendar you might use sampling to determine whether the treatment has worked. Typically you would sample before and after treatment.

 

If you use an IPM approach you would sample regularly to monitor mite load and apply a range of treatments as and when certain thresholds are reached.

Hi Rob, what is your threshold for treatment - the control of Varroa book I have suggests 40 varroa per 300 bees as needing treatment - but I've noticed some of my hives at that point start to get DWV. I am tending to treat anything over 10 Varroa per 300 - do you have a set threshold?

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Hi Rob, what is your threshold for treatment - the control of Varroa book I have suggests 40 varroa per 300 bees as needing treatment - but I've noticed some of my hives at that point start to get DWV. I am tending to treat anything over 10 Varroa per 300 - do you have a set threshold?

It's been said that the thresholds are dropping because the mites are vectoring more damaging viruses to the bees - particularly deformed wing virus.

 

I must start out by saying that this season is an experiment for me. I have used strips in the past but would like to be less dependent (independent perhaps) on synthetics. My aim is to keep varroa under 2% (6 mites per 300 bees) by treating regularly with oxalic acid sublimation. Zero mites will get no treatment. 1-2 mites will be treated once per month. 3-5 mites will be treated weekly. Sampling is monthly and each hive remains at a given treatment threshold until subsequent sampling says otherwise. OA doesn't kill mites in capped brood. So where mites exceed 2% and for a more thorough knock down I plan to also treat with MAQS.

 

I've made a wiring harness for my truck so I can treat repeatedly without my battery going flat. My big area for improvement at the moment is sampling accuracy. I had some worrying results last month with up to 14 mites in a sample. Reflecting on the history of that colony and with sage advice from @deejaycee either there was a massive reinvasion or my sample was too big. I suspect the latter.

 

Measuring 300 bees is a bit of an educated guess. So instead I'm going to use a digital scale to measure my jar before and after bees are added. I'll alcohol wash a couple of samples to get an accurate count and to confirm I'm not missing mites. with this information I'll be able to calculate % mites per bees from the weight and correct for any over size samples.

 

I'll finish by repeating that this is an experiment. The thresholds and treatments may change. I will use synthetics without hesitation if necessary.

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Hi Rob, what is your threshold for treatment - the control of Varroa book I have suggests 40 varroa per 300 bees as needing treatment - but I've noticed some of my hives at that point start to get DWV. I am tending to treat anything over 10 Varroa per 300 - do you have a set threshold?

Yep, that threshold is out of date . Regular sampling is becoming more and more necessary to monitor what works or not . Good advice above from @Rob Stockley :)

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Thanks guys - it looks like I'll need to do a winter treatment from now on if we are going to have these warm winters ( my hives had drones throughout the winter and the ones with drone brood sure bred up the varroa) so I might have to go for a vapouriser at some point.

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our thresholds can change a bit with time of year and history of that hive.

But in general anything with more than 3 mites in a sugar shake results in treatment.

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Well, I sampled my bees using an alcohol wash today ... I counted 22 mites on 120 bees (18% infestation - gulp)! I'm really glad I decided to count the bees after sampling too, as my 'half cup of 300 bees' turned out to be a whole lot less!

 

Thanks everyone for your advice and discussion around this topic, it's been really helpful. Threshold treatment times are what most horticultural industries use these days for pest sprays, etc., so I reckon bees must be about 15 years behind! I think as resistance develops, it's important to embrace the integrated pest management approach and use all of what we have to control varroa.

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Well, I sampled my bees using an alcohol wash today ... I counted 22 mites on 120 bees (18% infestation - gulp)! I'm really glad I decided to count the bees after sampling too, as my 'half cup of 300 bees' turned out to be a whole lot less!

 

Thanks everyone for your advice and discussion around this topic, it's been really helpful. Threshold treatment times are what most horticultural industries use these days for pest sprays, etc., so I reckon bees must be about 15 years behind! I think as resistance develops, it's important to embrace the integrated pest management approach and use all of what we have to control varroa.

This is what I really like about this forum. A question is asked, and someone learns to be a better bee keeper almost instantly .

 

In my opinion, varroa sampling is possibly the most important part of successfully getting bees from one season to the next, alive and healthy

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@Rob Stockley - when would you suggest taking another sample once the varroa treatment has finished (to check efficacy)?

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@JayBee I would sample three times.

  1. Just before treatment so you know where you started
  2. A few weeks (some suggest a few days) into treatment checking for a significant reduction in mite load.
  3. When the strips come out to confirm that the treatment has worked.
    • One or two mites would be disappointing but acceptable - close monitoring may be required later in the season.
    • Three or more and I would follow up with five weekly doses of OA vapour.

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This is what I really like about this forum. A question is asked, and someone learns to be a better bee keeper almost instantly .

 

and I'm sitting in the penguin cafe in Portobello eating freshly iced carrot cake and a long black, life's good and so is bobby bee keeping

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life's good and so is bobby bee keeping

What does a bobby bee look like please ?

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Wearing a funny bat.

:)

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@JayBee I would sample three times.

  1. Just before treatment so you know where you started
  2. A few weeks (some suggest a few days) into treatment checking for a significant reduction in mite load.
  3. When the strips come out to confirm that the treatment has worked.
    • One or two mites would be disappointing but acceptable - close monitoring may be required later in the season.
    • Three or more and I would follow up with five weekly doses of OA vapour.

 

All things being equal, our regime is to test before treating, two hives have not required treating.

Two weeks after the treatment period has finished, we test again once everything is settled down.

All things are not equal, but that is generally our plan "a"; a test before and a test after.

We have sometimes had more than 3 mites in the second test and have gone into another treatment cycle with something different.

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What methods of testing for varoa do you recommend? Is the sugar shake the most effective? Or are there others that are less talked about?

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What methods of testing for varoa do you recommend? Is the sugar shake the most effective? Or are there others that are less talked about?

Look here : Control of Varroa

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What methods of testing for varoa do you recommend? Is the sugar shake the most effective? Or are there others that are less talked about?

 

recommend sugar shake for hobbyists and beginners. It is not the most accurate. However, it is relatively easy, nobody dies and the accuracy is sufficient at the current time.

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recommend sugar shake for hobbyists and beginners.

 

Excellent will give it a go tomorrow if it's still fine. Thanks!!

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