Beesource Beekeeping Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
678 Posts
Discussion Starter · #1 ·
My inspections seem to tear up brood from between boxes. At times also burr comb has something in it. When the brood is exposed, I take the time to look for varroa on these. This past weekend I saw no varroa, in the brood. Does anyone know if this is a reasonable way to check varroa levels? Seems if there are non on the emerging bees I should be in good shape. ??
 

·
Registered
Joined
·
2,942 Posts
According to Swiss research varroa in drone cells is not a good way to estimate varroa populations. Varroa numbers increase and decrease, they have had changes up to 600% in the space of a week. The method considered best is the check by washing of about 300 workers taken from open brood frames in the brood nest.
 

·
Registered
Joined
·
6,558 Posts
Culling and examining drone brood is the method I use most of the summer. You have to realize that the cells you are checking relate to mite numbers several weeks ago so won't catch an influx of recent mites from collapsing hives. Also cells on frame bottoms or outside frames are not the best location to sample from. The alcohol wash of young bees from the brood nest center are one of the best real time indicators.
 

·
Registered
Joined
·
5,768 Posts
when you start to see more than one mite per drone cell, I start using other methods to get a better mite count.
 

·
Registered
Joined
·
3,084 Posts
I made some drone-sicles recently and figured, "what the heck." It is a nice science project at any rate. It seems a waste to kill a frame of varroa magnets and not learn something from their sacrifice. Am I being too sentimental about insects? I should pull the frame back out and check for more and get some statistics, but I can appreciate that this is an exercise for researchers and nutty hobbyists, and that commercial beeks will think it is a waste of time.

My observation: you only want to look at the better-developed pupae. If they're not dark-eyed they're probably a mushy mess, and the mites won't have developed anyway. If you can just count the ones almost ready to emerge you should get a more meaningful count.

The partly-developed varroa are translucent white and have a different body shape than the adults. They're hard to spot without a microscope. I'm using a 10x/30x inspections scope, but you might manage with good eyes and a good hand magnifier.

So far I've looked at 4 well-enough developed (and probably should go for about 30 for the numbers to mean anything). I found one immature mite. That frame was collected 1 week ago, and the hive dropped 7 mites after a sugar dusting over the last week. A sugar roll on Sunday produced a 2-mite drop from about 300 bees.
 

·
Registered
Joined
·
3,084 Posts
I finally got around to picking some more drone-sicles off the green board. Just counting pupae that were purple-eyed or even closer to emerging, the total examined was 64. I have a guide that suggests 200 is a better number but suggested a capping fork to pull them out en masse. I was working with pointy tweezers and checking them out with a dissection scope at 10X. My scope is rigged to mount a camera, so I took some pics. Don't look until after dinner.

Sharp eyes can spot the brownish adult mites without magnification.

There are online writeups of the varroa life cycle ... I didn't get too picky about distinguishing males from immature females. I did distinguish dark ones (adult or nearing adult) from translucent immature forms.

In 64 drones, I found 6 with mites. Some had multiple mites so I found 16 mites total. About 6 of the mites were immature.

Be sure you look down into the cells once you pluck a drone out. Sometimes a mite falls off or is stuck under the membrane.

DroneSicleMite000Compr.jpg
DroneSicleMite003Compr.jpg
DroneSicleMite005Compr.jpg
DroneSicleMite006Compr.jpg
 

·
Registered
Joined
·
266 Posts
Fantastic photographs, Phoebee! Gorgeous and sad.

Hubby and i just ordered a sticky board with a screen over it for our solid bottomed hives. While our attempts at getting a count won't be nearly as meticulous as yours, i'm hoping to get a fairly accurate figure (i'm expecting it to be pretty high since there was at least one worker bee with deformed wing virus). Maybe i'll be pleasantly surprised ...
 
1 - 7 of 7 Posts
Top