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Double Screen Board

10K views 18 replies 10 participants last post by  Bubbles 
#1 ·
Brushy Mountain Bee Farm sells a double screen board. Has anyone had any experience with this board?
 
#2 ·
I have several of thiers (Brushy Mt.). Betterbee also makes one. They are a handy piece of equipment to have around. They can even work for a screened bottom board in a pinch, but are especially nice for introducing a nuc to a new hive or keeping a nuc warm in the early spring. Of course they are designed to be a "Snelgrove" board to use his (L.E. Snelgrove's) rather unique method of swarm control. However, I have not attempted to do that with them.
 
#6 ·
According to the Betterbee catalogue:

Double Screen, also called Snellgrove board, allows you to run a 2 queen hive. the double scren keeps the bees above from communicating with those below, while still permiiting the heat to circulate in the hive.

THere are multiple entrances to permit you to add or subtract bees. from either the top or the bottom.

"We only recommend the use of a Double Screen to the professional hobbyist who has both te time and inclination to manipulate a hive for maximum population and production."

Now that is a good one: "profesional hobbyist"!

My definition: One who spends excessive time and money in pursuit of intangible and indefinable goals, under the guise of the profit motive.
 
#7 ·
It's useful for many things. The double screen keeps the bees from each side from harming each other but lets the smells and heat through. So they can adapt to each other and a nuc on top can get some heat. I don't recommend it in a Northern climate when the weather is cold enough to make a lot of condensation. Snelgrove's method is a bit complicated to explain, but not really that complicated. Try a search online and you might find a good illustration of it.
 
#8 ·
another use I've heard of is to put it on top of the hive, then put a box with several frames of fresh eggs.
the upper box get's the benefit of climate control from the hive below but since they can't pass QMP thru the double screen they think they're queenless. once the get some queen cells going you can split them up into mating nucs
I'm planning to try this to get a few queens this spring

comments on how to make this sucessfull appreciated

Dave
 
#12 ·
I made one yesterday, adapted the plans a bit to accomodate using 3/8" plywood instead of 1/4" so it's 1 3/8" tall instead of 1 1/4" and my lumber 7/8" but otherwise the same. Almost. Actually I cut the entrances at 45º so they're a tad bit narrower but I made them 1/4" longer. Came out well, all in all.

So, why all the entrances? I mean it looks cool, but realistically, what do you need 8 possible entrances? It seems you could get by with 2 entrances, one on either end on opposite sides and call it good?

I'm planning on building another one of these days after pondering some design changes.
 
#13 ·
>So, why all the entrances? I mean it looks cool, but realistically, what do you need 8 possible entrances? It seems you could get by with 2 entrances, one on either end on opposite sides and call it good?

It's a Snelgrove board. It's actual purpose was to run a two queen hive with one above the screen and one below to eliminate swarming while boosting the hive population. Basically you keep rotating which entrance actully goes where to keep fooling the bees into returning to the bottom box instead of the top one. Do a search on "Snelgrove" on the internet and maybe you can find a description of the full method. For the Snelgrove method you DO need all those entrances.
 
#15 ·
Well I've actually found very little on the web about the Snelgrove method of swarm control. I found various attempts to explain it in simplified terms. Here's the best one:

http://www.derbyshire-bka.org.uk/wiki/index.php?title=Snelgrove_Swarm_Control_Method

I can only gather that it ain't the most popular swarm control method these days


I didn't initially build my double screen board as a swarm control tool. I've run across a number of different manipulations which called for one, everything from queen rearing applications to introducing nucs to making splits. So I thought I'd build one. Now I'm wondering more about it's original use.

I suppose I should look for a copy of Snelgrove's book. Has anyone here ever used a snelgrove board for swarm control utilizing snelgrove's method? Barring that, does anyone have any good links to the snelgrove method?
 
#16 ·
George Fergusson . . .
Here is some misc info, if any of its helpful, you owe me


DOUBLE-SCREEN (Snelgrove board, Division Screen or Board, Screen Board)
A rimmed, inner cover-size board containing two layers of screen (8x8 mesh) at least 1/2” apart so individual bees cannot pass “queen substance” from one side to bees on other side of screen [Ref 15,p89 and BC 5/04, p51]. Used to make an increase, split colony, or to start a 2-queen colony [Ref 15,p89].
Should have a 3/8" to 1/2" rim on top w/ a 1-1/2" opening in one end to provide an entrance for upper colony [ABJ, 3/06, p226].

Method #3 (Creates a 2-queen colony) - Frames of emerging brood and bees are placed over double-screen or adapted inner cover (allows heat from unit below to support development of colony above) and given a very small opening located at the back of parent colony (180o different). (Place double screen on new body w/ entrance to rear and place excluder on top of double screen for “insurance” [Ref 7, p27].) Upper colony is given a queen cell, a virgin queen, or a mated queen (depending on time of year). Such colonies are made up in late April to early May in northern states, and allowed to grow rapidly. When clover bloom is about to begin (or primary flow) double-screen is removed and colonies are combined via a sheet of newspaper. A single queen (usually the new one) is allowed to live while other (old) queen is removed. The combined population of 2 brood nests is now collecting one very large honey crop. This method works well when beekeeper has plenty of equipment, a relatively sure honey crop, and able to stack equipment quite high on hive stand. Unfortunately, in a summer dearth, this huge population is a lot of bees to feed [BC, 3/05, p45].
 
#17 ·
Well Dave, I already owe you


I'll assimilate your information after dinner, I can't think right now what with my stomach growling at me.

For what it's worth, I just found Snelgrove's book available from the Maine State Beekeeper's Association Lending Library. I guess that means I'll need to renew my dues........
 
#18 ·
I will probably NOT bother with getting Snelgrove's book, perhaps next winter I will when I'm bored. I did find sufficient information about Snelgrove's swarm management method over on BEE-L so I could decide it's not something I'm going to be trying anytime soon. It apparently is successful at keeping hives from swarming, but it's not without drawbacks, many of which are similar to those you'll have with any two queen hive. This isn't really the proper forum for an indepth discussion of Snelgrove's swarm managment method but we're discussing the hardware involved, might as well tack on some information about the method itself.

Date: Mon, 25 Aug 1997 13:57:22 EDT
Reply-To: Discussion of Bee Biology <BEE-L@CNSIBM.ALBANY.EDU>
Sender: Discussion of Bee Biology <BEE-L@CNSIBM.ALBANY.EDU>
From: Aaron Morris
Subject: Snelgrove swarm control
Content-Type: TEXT/PLAIN; charset=US-ASCII

> Subject: Snelgrove Swarm Control System
> Can anybody enlighten me on the Snelgrove Swarm control system.?
>
> I have come across it somewhere in the beekeeping material which I have
> read, but cannot recall where.
>
> This is my first year in beekeeping and I imagine that I am facing swarms
> next year.
>

This question is too timely for me to be a coincidence. I just finished reading last night, _Swarming:_It's_Control_and_Prevention_ by L.E.
Snelgrove. Written in the 1930s (1934?) the book speculates on the causes of swarming (the intro of the 1995 reprint points the reader to more current work by Winston) and discusses methodologies of the day to deal with swarming.

Snelgrove designed a piece of equipment called a Snelgrove Board (the coincidences never cease!). A Snelgrove Board (SgB) is a piece of equipment very much like an inner cover with a few "extras". Rather than a hole in the center of an inner cover, the SgB has a much larger opening that is double screened, hence a SgB is sometimes referred to as a double screen board. Additionally, a SgB has entrances on three sides of the board on both top and bottom (six in total). The side with no entrances is the front of the board. For later discussion imaging that the top entrances are numbered 1, 3 and 5 for the right, back and left entrances and the bottom entrances are numbered 2, 4 and 6 for the right, back and left respectively. Towards the beginning of swarming season a SgB is used in combination with a queen excluder and hive
manipulations on a double brood chamber colony to simulate a swarm while keeping both the parent population and swarming population combined at the same location!

How is this possible?

The hive manipulations consist of segregating the brood frames so those with eggs, larvae and brood are moved to the top hive body and empty frames are segregated to the lower body. This is another technique that hinges on finding the queen. When she is found she is moved to the lower brood chamber on a frame of eggs, larvae and unsealed brood. This should be the only frame in the lower brood chamber with any stages of brood - all other frames in the lower brood chamber should be empty or contain only stores (pollen, nectar and honey). Above the bottom brood chamber go a queen excluder, super(s), and the top brood chamber containing occupied brood frames. Three days later the super(s)will be occupied and the nurse bees will have passed through the queen excluder to the brood frames in the top chamber. At this point in time the SgB is inserted with entrance 1 open - all other entrances on the SgB are closed. For the next few days, field bees from the top brood chamber will exit through entrance 1 and join the population below the SgB by using the original front entrance. One week after the initial manipulation the beekeeper closes entrance 1 and opens entrances 2 and 5. Thus, the bees from the top brood chamber that "graduated" to field bees return to and reinforce the lower population by using entrance 2.

During the next week the top brood chamber bees that become field bees will get accustomed to using entrance 5. While the bees in the lower chamber use either the original front entrance or entrance 2. At the end of the second week the beekeeper closes entrances 2 and 5 and opens entrances 3 and 6. Again the top brood chamber field bees reinforce the lower population by returning to the left hand lower entrance (entrance 6) and the top back entrance (entrance3) becomes the top brood chamber's main entrance. By using the entrances in the SgB in a round-robin fashion, the top brood chamber becomes a "bee generator" for the lower colony. The top brood chamber, being queenless and initially containing all the eggs, larvae and brood will immediately commence to raise a new queen. However, the top brood chamber will not swarm because the population never reaches sufficient numbers to cast a swarm. The bottom chamber never swarms because the brood rearing cycle was interrupted by the initial manipulations.

This method artificially casts a swarm from a colony, keeps both populations in a single unit, effectively sets up a two queen colony, and leaves a requeened colony at the end of the season when the upper and lower chambers are reunited. I can't wait 'till next year to give it a try. I already have the SgB, which I have always used as double screened boards to make splits, but I have never used them as intended. Live and learn. I'm sorry if the technique looses in the translation, but it is not my intent to rewrite Snelgrove's book. For full details and clarification, read the book. I found it fascinating in spite of its years!

Aaron Morris - I think, therefore I bee!
Here's another that discusses some of the downsides:

Date: Wed, 23 Dec 1998 10:51:34 EST
Reply-To: Informed Discussion of Beekeeping Issues and Bee Biology
<BEE-L@CNSIBM.ALBANY.EDU>
Sender: Informed Discussion of Beekeeping Issues and Bee Biology
<BEE-L@CNSIBM.ALBANY.EDU>
From: Aaron Morris
Subject: Snelgrove for swarm control, an update
Content-Type: TEXT/PLAIN; charset=US-ASCII

I received in private E-Mail a query regarding my results employing Snelgrove's technique for swarm control. Having never posted my results to BEE-L, I offer the following tidbits as my Yuletide Offering to all my friends and beekeeping chums along with my sincere wishes for a joyous Christmas and Happiest of New Years!

For those who missed the initial description of Snelgrove's techniques, send a single line of mail to:
LISTSERV@cnsibm.albany.edu
that reads:
GETPOST BEE-L 17749

"Yes, I tested quite heavily Snelgrove's methods this season. I've made no attempts to summarize my results and I don't have my notes with me at the moment, so what I'm writing is off the top of my head.

Overall I would say I had great results, which is to say I was able to control swarming in all hives on which I used Snelgrove's methodology. I experimented with at least 40 colonies none of which cast swarms.

However, this success in swarm control has to be weighed against the burden of implementing the control. Initially setting up the arrangement (moving/segregating frames of sealed brood into the box below, open brood and eggs above) was new and exciting and I enjoyed the whole process. Queen excluder above the bottom brood chamber, honey supers, Snelgrove Board (SgB) and top brood chamber created quite a tall hive! This is where the methodology became tedious. You can imagine the task required to examine the bottom brood chamber or even just evaluating the honey supers. Any time you want to look into the colony below you must first remove the top colony. Further exacerbating this task is the fact that the SgB is not attached to the top colony, so it became problematic with bees on both top and bottom of the SgB when I removed it working my way down the hive. Attaching the SgB to the top colony would ease this problem.

Now, Snelgrove's method effectively sets up a two queen colony and you have all the management headaches associated with them - populous hives requiring MANY honey supers and lots of over the head lifting. Some hives required ladders to work and schlepping bees while precariously perched atop a 6 foot step ladder is flirting with disaster. Fortunately none struck.

Those problems aside, I ran into other snags that weren't anticipated or elucidated in Snelgrove's writings. Initially things went quite well, all of the top hives which were queenless (the original queen goes to the colony below) started raising new queens or accepted queens procured from breeders. Most colonies readily accepted introduced queens, which is what you'd expect. The top colony ends up with mostly young bees and nurse bees, as the field bees return to the original hive entrance. However, there were a few of the top colonies that simply refused to accept introduced queens. Some of these I tried two or three new queen introductions, which amounted to a lot of wasted money and work on my part and stress on that colony. After prolonged queenlessness I had to recombined the top colony with the original colony. I quickly learned that if the top colony did not accept the introduced queen that rather than cutting out established queen cells and trying another introduction the colony should be left alone to raise its own queen. In retrospect that should have been obvious since by the time I determined an introduced queen was rejected there is no chance of that colony raising a new queen because the eggs have all hatched and the larvae are too old. The lesson here is bees know more about bees than do beekeepers.

Next snag: Not all the top colonies left alone to raise their own queen ended up with a successfully mated new queen. This was minimal, two or three, but again the net result was recombining the top with the bottom, lots of wasted energy on my part and stress on those bees. I would not chalk this up to a problem with Snelgrove's methods per se, it's more of
a general problem facing queen breeders. Not all mating nucs are successful, plain and simple, it comes with the territory.

Another problem I ran into but did not expect from Snelgrove's writings came when I started employing the many entrances/exits in the SgB used to transfer bees from the top colony to the bottom. Snelgrove claimed that the bees will readily transfer between the colonies because they are familiar with each other's smells due to the double screen separating the two colonies. As Porgy sang, "It's ain't necessarily so!". Some bees transferred readily between colonies, some did not (or at least this is how I interpreted some of my results). Some of my bottom colonies ended up queenless soon after I opened/closed the different doors combining the top colony field force with the bottom colony. I cannot say with assuredness but I suspect that sometimes the bottom colony's queen was assassinated by the foreign bees. This may not be the case, the bottom queen could have met a different demise. But I had enough of the bottom queens disappear that I suspect the bees may not mix as freely and amicably as Snelgrove led one to believe.

The final problem I ran into which Snelgrove surely noticed but did not include in his writings was with pollen in my honey supers. When I switched the doors to move field bees from the top colony to the bottom I witnessed more than many top field bees bringing their pollen loads back into the bottom honey supers. Bees tend to store pollen near brood, and the top colony field bees stored pollen near their former brood chamber. This was not a big deal for my extracting supers although I now have a lot of pollen plugs in what had been heretofore strictly honey combs. However, Snelgrove claimed that his methods can be ideal for comb honey production and in fact recommends it! I had to cull nearly half of my comb honey harvest due to the pollen storage problem. I have literally hundreds of Ross Rounds that are not fit for market because the top colony field bees stored pollen in the comb honey supers. To me this is a significant problem.

So, did Snelgrove's methods control swarming? Yes, without a doubt. However I wonder if this might be accomplished in other ways. Snelgrove's methods actually allow a hive to swarm while keeping the entire population intact, a unique management technique. When it goes right, the resulting colonies are gangbuster hives which can out produce other hives two and even threefold! However I am not convinced that the energy expended to successfully employ his technique is proportional to the increased yield. If colonies are few and time and energy are bountiful, I recommend Snelgrove's technique. On the other hand, a beekeeper can realize like harvests expending less energy with a few more hives having lower average yields. Swarming can be controlled by making splits - populations are not kept intact, split hives will produce less, but in the long run return on your investment (time and energy) is greater.

I think in the future I will use my Snelgrove Boards to make my splits atop established hives to control swarming, but I will move the splits off the established hive to stand alone rather than utilizing the split to enhance the original hive. I can then use these splits as needs dictate during the season without enduring the unforeseen problems I encountered following Snelgrove's writings. As they saying goes, if it sounds too good to be true then perhaps it is.

Thanks for asking for an update, it's nice to see folks perusing and using the BEE-L archives!"

Sincerely,
Aaron Morris
There's more to be had on BEE-L but you get the gist of it.

George-
 
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