Varroa tales

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Mark Lewis

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Sep 19, 2023, 2:15:42 PM9/19/23
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The community of honeybees in question began as a side-by-side divide (split from one of Bill's March 27 packages) with the mother queen moved over. On Aug 9 there were 0 mites on the sticky board but I found some in the drone brood so I removed all drone brood I could find. I returned on Aug 20 with Formic Pro placing 1 patty and adding a 2nd 10 days later, per label instructions for this style.

On September 14, I placed a new sticky board and 48 hours later found 64 mites had dropped! 

I've ordered Hopguard 3 to install asap. Also will plan to follow up with oxalic in November.

Anyone have advice or commentary? 

Larry V, how often have you seen a 64 mite drop except right after you started a new treatment? I know recommended threshholds for alcohol washes but am still learning how to interpret drops.

I'll say it's another thing pushing me to try the Single Brood Chamber approach (having that set up by the time of the mid-July dearth) b/c I feel like the brood may have been too scattered across the multiple box stack and this could present a problem for Hopguard too. The bottom box is often largely abandoned by this time of year, but I'll need to confirm this, which can be disruptive on the dearth-y days of fall.

The 2x10 day Formic approach may cause less of the disruption that leads to supersedure, though in retrospect I would not lament the loss of this productive but mite-vulnerable queen. 

Mark

Mary Glenn

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Sep 19, 2023, 3:05:01 PM9/19/23
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Hi Mark,
I have a Slovenian style hive, and I noticed a week or two ago that the bottom box was nearly empty---honey and brood were both in the 2nd box up.  Is it OK to leave them that way for winter?  Or should I move them down?
(Just asking because you note that often the bottom box is often largely abandoned by this time of year.)
Mary

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Sadie

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Sep 19, 2023, 3:08:58 PM9/19/23
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I would swap boxes, by winter be sure there's resources in the upper, they'll usually migrate up over winter.



Mark Lewis

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Sep 19, 2023, 4:00:49 PM9/19/23
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Mary, 

For reasons of over-wintering volume, I think it is preferable to remove the bottom box. But yeah, it can be a tricky operation to do this time of the year because of potential robbing interest. That’s why I’m thinking of trying to have them set up in a Single Brood Chamber under a queen excluder by around July 10 next year, near the end of the usual big nectar flow. Should make it easier to focus on Varroa issues. 

Mark

sent from phone

On Sep 19, 2023, at 3:08 PM, Sadie <sa...@mit.edu> wrote:



brendaw321

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Sep 19, 2023, 4:04:33 PM9/19/23
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Have you done a mite wash? Sticky boards are circumstantial and not very accurate. A certain number of Mites die everyday of natural causes and these are included in a mite drop, and while alarming, a mite wash is more accurate. 

Also the 1 pad x 2 times of Formic Pro is not as effective when there is brood present as the 2 pads x 1 time method. 

Brenda 

Larry vandeVenter

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Sep 19, 2023, 5:54:40 PM9/19/23
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Mark: I never do the single strip FP treatment. I think you experienced a mite resurgence due to average low FP concentration with the single strip approach. The kill efficiency for mites under cappings was low.  I see this resurgence from low kill efficiency about 20% of the time even with the two strip 14 day treatment that I always use. Sadly I also see queen issues about 10% of the time too. I run all mediums so the number of boxes and where I place the treatment in either a 3 box hive or a 4 box hive can make a difference too. At between 16 days to 23 days from the start of my treatments the mite drop per day should be back below my 8 mite per day treatment threshold. If I don’t see that I know I’m going to see a resurgence right away. I had one today that is building from 30 per day up to 42 per day at day 23 from treatment. This was a second FP treatment because the first one had a resurgence  And I’ll have to treat for a third time and I’ll probably use OA now so I can avoid the queen issues that could affect winter bee production and doom the hive for winter survival.  

Larry
Larry VandeVenter


On Sep 19, 2023, at 3:08 PM, Sadie <sa...@mit.edu> wrote:



Mark Lewis

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Sep 19, 2023, 10:47:39 PM9/19/23
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Thank you Brenda and Larry. So 8 mites/day is your threshold Larry? I was trying to remember. Thank you. I should be able to remember that since it's close to the 9/300 is the alcohol wash IPM threshold. I saw that U of Guelph uses common file folders for their mite drop counts-- good for labelling and transporting. I don't think they listed a threshold in their video. 

A few miles from this hive, I treated 3 other hives in the same way except starting 6 days earlier, Aug 14. One of those (#3) even had phoretic mites on nurse bees, scary. Last weekend I tested the mite drop of these after 48 hrs and it came out to 1 in #1, 7 in #2, and 1 in #3. I did an alcohol wash on #3 and found no mites. 

Ach ja... I'll keep pondering this one. Thanks for brainstorming with me about it.


Larry vandeVenter

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Sep 20, 2023, 1:16:04 PM9/20/23
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Mark: FYI I use an alcohol wash threshold of > 1% or 3 mites per 300. Yes. More conservative. I find the 8 mite per day drop corresponds to about 1.25% infestation. 

Larry

Larry VandeVenter


On Sep 19, 2023, at 10:47 PM, Mark Lewis <helloma...@gmail.com> wrote:



Mark Lewis

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Sep 20, 2023, 8:10:16 PM9/20/23
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Oh my —palm to head— major apologies, I’ve just realized that I mixed up the mite drop counts of the two side by splits. This is an advantage of Guelph’s file folder system— they were still sitting on the floorboard of my truck, labeled. Results make much more sense now. 

The 64 mite count was the one that requeened over the summer and alcohol wash found only 2 mites on Aug 20 so I didn’t treat. 

Larry, thank you for that excellent detailed info, 8 = 1.25%

Mark

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On Sep 20, 2023, at 1:16 PM, Larry vandeVenter <lvande...@comcast.net> wrote:

Mark: FYI I use an alcohol wash threshold of > 1% or 3 mites per 300. Yes. More conservative. I find the 8 mite per day drop corresponds to about 1.25% infestation. 

Mark Lewis

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Sep 28, 2023, 7:38:23 PM9/28/23
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Two day ago, I placed 4 strips of Hopguard in the hive that previously had the 64 mite count. If anyone is wondering about the efficacy of Hopguard III, check out this photo of the mite drop after 48 hours.

Mark
IMG_5836.jpeg

Tyler Jenkins

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Sep 28, 2023, 8:21:57 PM9/28/23
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Wowza! Thanks for sharing 

Tyler

Sent from my iPhone

On Sep 28, 2023, at 7:38 PM, Mark Lewis <helloma...@gmail.com> wrote:

Two day ago, I placed 4 strips of Hopguard in the hive that previously had the 64 mite count. If anyone is wondering about the efficacy of Hopguard III, check out this photo of the mite drop after 48 hours.
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