Slatted racks and screened bottom boards

[Drugstore]

The use of slatted racks has many positives, but has anyone found them to be an impediment to Varroa mites falling through to a screened bottom board?

[Michael Bush]

I don't think it matters, but Betterbee makes them with the slats lining up with the frames above by running the slats the other way. I really don't think SBB make that much difference on mites anyway, but every little bit helps. smile.gif

[BULLSEYE BILL]

Since the idea behind the slatted rack was two fold, one, to break up drafts and two, to provide cluster space, I think that the bees clustering on the rack would catch mites that would have otherwise fallen to the bottom of the hive. So, I haven't been using them.

[Drugstore]

Michael B,
Thanks for the answer. My concern is that the falling mites would fall on top of the racks and just climb back up. Perhaps making mite counts less accurate on sticky boards or mites not falling through the sbb when the sticky boards are not in place.

[Drugstore]

Bill,
I'm thinking like you, but I hate the thought of not using the racks during the heat of summer.

[Michael Bush]

>Thanks for the answer. My concern is that the falling mites would fall on top of the racks and just climb back up. Perhaps making mite counts less accurate on sticky boards or mites not falling through the sbb when the sticky boards are not in place.

I see that. Perhaps they aren't as accurate. I don't know. I was using slatted racks on most of my hives when they were ten frame mediums and I have them on none of them now that they are eight frame mediums. I didn't really see a difference. I can't say how that works or doesn't. But then I also don't have a bottom entrance anymore, so it's less likely all the returning field bees will be clustered down there on the bottom even if I had the slatted racks in.

[George Fergusson]

I think screened bottom boards are most useful for ventilation and for mite monitoring. I don't think they trap a whole lot of mites that weren't about done for anyways and the estimates that I've heard about screened bottom boards trapping 10% to 20% of your mites are exagerated. In other words, if you're expecting significant mite relief simply by putting screened bottoms on your hives, I think you're in for a disappointment.

Some live mites obviously will end up there, but most of the mites you find on the bottom board are dead or dying, either having been groomed off and injured, they've ended their useful life, or they failed to mature in the cells. Most of them fall as a result of breeding activities, which is why you see many less mites on the bottom board when hives are broodless, such as in the winter. You see more mites on the bottom board when the bees are actively brooding. You'd think, with more phoretic mites that you'd see more on the bottom, but the reverse is true. Mites are designed to stick to bees. Effort has to be made to dislodge them. They don't reproduce exponentially by oops! falling off of bees smile.gif

Therefore, I don't think slatted racks would significanty reduce either mite drop counts or mite fall. It would be an interesting experiment I guess. I think mites destined for the bottom board will find their way their with, or without slatted racks. I've never tried a slatted rack but plan to this summer if I find some, or find the time to build some.

[BULLSEYE BILL]

>I'm thinking like you, but I hate the thought of not using the racks during the heat of summer.

I would hate the loss of using a SBB more than the slatted rack. The difference is remarkable between the use of SBB and solid bottoms. When using the SBB there are hardly any bees clustering on the outside of the hive.

I would expect that nighttime clustering on the rack would be high with or without the SBB. I really don't want a large number of bees clustering anywhere in the summer, I would rather they spread out and do something constructive. ;)

[Michael Bush]

>I would hate the loss of using a SBB more than the slatted rack. The difference is remarkable between the use of SBB and solid bottoms. When using the SBB there are hardly any bees clustering on the outside of the hive.

I agree. I think the main advantages of the slatted rack have been handled by the SBB. Ventilation was probably the primary reason that the slatted rack succeeded. If I had to choose I'd take the SBB. Both are nice.

[LaRae]

I have 2 slatted bottom boards which I have yet to figure out if I even need to use. I put the sbb on when I assembled the hives.

So why would a person use slatted bottom boards if they already have sbb? If I don't need them then I'm going to sell them.


LaRae

[Michael Bush]

If I had slatted racks on I wouldn't be so much against leaving the SBB open in the winter. The point of the Slatted rack is twofold. To control the ventilation and to provide a place for the bees to cluster. It will still do these two things although the SBB will provide adequate ventilation (at least with some kind of top vent too) the slatted rack will still baffle it to keep it from being drafty.

You can do fine without them. But if you have them, why not try them?

[LaRae]

Well....partly cause they are still unassembled in a box <G>

Around here (and we are probably milder in winter here than you are) at least half the beekeepers leave their sbb on year round. Although I did use straw bales to buffer around my hives. Very few people wrap their hives here.

I don't quite get the idea of the bees clustering on the slatted boards???


LaRae

[Dave W]

>I don't quite get the idea of the bees clustering on . . .

I don't think they cluster ON, they may cluster UNDER where there is MUCH more room.

Without a SR, the distance from the bottom of frames to bottom board is 1" (7/8 + 1/8).

With a SR, distance from SLATS to frames is maybe 3/8" (maybe less), not much room for clustering. UNDER slats is more that 2".

If all your mites to fall through the 3/8" wide "cracks" between the slats (dont acccumlate on top), I guess the total amount on sticky board would be the same w/ or w/o.

A SBB will NOT "increase" mite drop much, if any. It just helps get rid of (they fall out of hive) any LIVE mites that fall down and MIGHT crawl or hitch-hike back into hive.

[ February 08, 2006, 10:59 AM: Message edited by: Dave W ]