# Integrated Pest Management Control of Varroa destructor



## Vance G (Jan 6, 2011)

Screened bottom boards fall into the Angel Farts category in varroa control. The only thing they do is reduce area where bees can raise brood. Reducing brood does reduce total varroa output but is hardly a laudable solution to varroa infestation. They may do less harm in the steamy south but do not pass the giggle test in my cold northern location.


----------



## Litsinger (Jun 14, 2018)

While the study does discuss the impact of screened bottom boards on varroa population (excerpt below), it appears the main reason for the recommendation is for diagnostic purposes:

_Debris from hives equipped with a screened bottom board can be examined for the presence of Varroa (Rosenkranz et al. 1997, Webster et al. 2000, Branco et al. 2006).

Delaplane and Hood (1999) described a late season economic threshold for an overnight (20 ± 4h) mite fall for their location in the southeastern U.S. as 59–187 mites for a mid-sized colony (one deep brood box and one medium super). While this threshold may not be appropriate for all locations and seasons, it can be used as an example of an ET for a colony of “average” strength.

Researchers testing the efficacy of screened bottom boards found that they indeed reduce Varroa populations (Pettis and Shimanuki 1999, Webster et al. 2000, Ellis et al. 2001, Rinderer et al. 2003, Harbo and Harris 2004, Delaplane et al. 2005), though they only provide a modest impact of about 11–14% (Delaplane 2005) and should not be used as a stand-alone treatment._


----------



## kilocharlie (Dec 27, 2010)

The main IPM use of the screened bottom board involves dusting the bees (much more thoroughly than originally recommended) with powdered sugar by means of a sifter. This is a MILD varroa treatment applied at the end of each hive inspection / visit. 

This practice has been shown to reduce ectopic mites in the hive by 30% each time it is applied.

I use a dry board while applying the sugar so that it does not reduce the stickiness of the sticky board. A couple minutes later, I draw out the dry board and replace it with the sticky board. 24 hours later, I check the sticky board and replace it with a tray of vegetable oil for use as a combined mite and beetle trap.

By adding 1/2 % malathion, it becomes an INTERMEDIATE varroa treatment. This dosage is minimally harmful to the bees, and many varroa destructor mites die from it. It is a practice used in Greece for years, and has been considered effective when done in repetition. The number of repetitions varied back when the research that I read was being done. I'll check to see if there is any conclusive statement.

Another active treatment is to install a drone comb in the early spring, and remove it 20 days later. Freeze it for at least 48 hours, even 72 hours to make sure all the mites die. Replace the drone comb with another empty one.

You can check the effectiveness of the drone comb by stabbing your cappings fork into the side of the comb and drawing the fork (with the grubs on it) up out of the drone cells. Do this BEFORE freezing, or wait for it to thaw afterward. You may be shocked at how many mites you find.

You may want to review Randy Oliver's 300 bee alcohol wash mite assay in www.scientificbeekeeping.com.


----------



## kilocharlie (Dec 27, 2010)

Oops! I just reviewed the drone comb procedure, and it can done right after capping - day 13 after egg-lay. Call it 2 weeks to make sure you get them all in the cells.


----------



## RayMarler (Jun 18, 2008)

Yes kilo,
In the past I did practice powder sugar dusting over a SBB as well as drone brood removal for mite control. It does work, but takes doing the powder sugar dusting once a week and drone removal as it's capped. Time consuming and a bit of manipulation. I have not practiced these procedures in 15 years and now use solid bottom boards because I think the SBB's make it harder for the hive to regulate inner hive environment.


----------



## kilocharlie (Dec 27, 2010)

You'll notice that my bottom boards are not open to the ground, but always have something solid - uh, or liquid - underneath. I only use the SBB's in the warm part of the year. All the metal comes out when the nights get cold. This should give the bees good control over the environment inside the hive. I also actively place and / or remove corks from up to 6 holes in each hive, allowing the bees to easily control the heat, moisture, and airflow, also providing upper hive entrance.

I'm starting to build deeper SBB's for the larger colonies that allow more clustering space below the brood nest. The populations in the Brother Adam hives top 100,000 bees quite often. These won't be used when colonies are below 60,000 bees.


----------



## RayMarler (Jun 18, 2008)

Sounds fine to me, but I'm going to stick with my solid bottom boards, but I am considering starting to use drone brood manipulations again, if I can snap out of my lazy ways that I've adopted over the last few years. I'm thinking a single foundationless frame and cutting out the comb into a solar melter might work pretty good. Problem is I'd need to build me a solar melter.


----------



## kilocharlie (Dec 27, 2010)

I see that Randy Oliver has changed from 70% alcohol to 91% alcohol to Dawn detergent at 2 tablespoons per gallon of water for his mite wash. With the detergent, he is letting the bees sit in the wash for 2 minutes then gently swirling them around for 1 minute.

I just read 4 of his articles on mite wash in succession. This should change my game a bit. I could be getting false negatives, missing mites that stayed up in the bees.

His use of a 10X makeup mirror beneath the jar is a huge step forward. You can really see the mites.


----------



## kilocharlie (Dec 27, 2010)

I'm building solar wax melter again soon - still looking around for a nice sheet of galvanized steel that holds 5 frames after being bent into a melter pan (my first one was large, but an inch too short to melt anything other than 1 frame at a time). A tilt-up stand in the back keeps is facing the sun better more hours of the day. A Fresnel lens gives me 2 more months out of the year which I can still melt frames


----------



## kilocharlie (Dec 27, 2010)

Mr. Litsinger - I'd hate to oppose Drs. Delaplane and Hood, but I can never imagine letting mite counts get that high! 

59 to 187 mites is reacting, not preventing. A beekeeper will be FAR more successful if he never allows 10 mites to fall from a mite wash. 6 mites in a 300 bee wash is around 2% infestation rate, time for action if that is March or April. That will kill a colony in November if left untreated.

We just got'ta stay on top of the game better than that.


----------



## kilocharlie (Dec 27, 2010)

Also, in re-reading my post #4 above, I notice that I made it appear that the malathion was added to the vegetable oil - it is not. Malathion is mixed 1 gram to 199 grams of powdered sugar and is mixed very thoroughly. 

One of my Greek friends says that they used to use it between 4 and 7 weeks in a row, 2 or 3 times a year.

I have no data about malathion's tendency to stay in beeswax. Until I find the studies, I would change out the treated combs annually at the very least.


----------



## Litsinger (Jun 14, 2018)

kilocharlie said:


> Mr. Litsinger - I'd hate to oppose Drs. Delaplane and Hood, but I can never imagine letting mite counts get that high!


Good point @kilocharlie.

I think this is why the first recommendation is:



Litsinger said:


> 1. _...it is necessary that beekeepers determine individual thresholds relevant to their location, management preferences, and management goals._


----------



## Rader Sidetrack (Nov 30, 2011)

kilocharlie said:


> I use a dry board while applying the sugar so that it does not reduce the stickiness of the sticky board. A couple minutes later, I draw out the dry board and replace it with the sticky board. 24 hours later, I check the sticky board and replace it with a tray of vegetable oil for use as a combined mite and beetle trap.
> 
> By adding 1/2 % malathion, it becomes an INTERMEDIATE varroa treatment. This dosage is minimally harmful to the bees, and many varroa destructor mites die from it. It is a practice used in Greece for years, and has been considered effective when done in repetition. The number of repetitions varied back when the research that I read was being done.


With my moderator hat on, I'm going to note here that malathion is an insecticide, and 'highly toxic' to bees. From one malathion product label:


> This pesticide is highly toxic to bees exposed to direct treatment on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds while bees are actively visiting the treatment area.


Kilocharlie's routine is to separate the bees from the malathion with a screen, but there are risks to that. As this use is not listed on the malathion package label, this kind of 'off-label' use is illegal in the USA.

More info on malathion here:


Malathion General Fact Sheet



That page notes that "Malathion vapor may also move long distances in air or fog." That could lead to honey contamination if supers are present.


----------



## Gray Goose (Sep 4, 2018)

As to the SBB vrs SBB ok sorry Screened Bottom board VRS Solid bottom board.
I am drifting away from the Screened BBs
When I count the winter losses the solid boards consistently do better. (for my location)

In a windy snow storm, I have seen an 8 inch drift inside the garage coming in thru the crack in the door.
IMO in windy locations this Screen can cause to much heat loss.

I have made some BBs with a 3 to 5 inch drawer under with a screen, above the drawer.
The only air flow then would be around the drawer face, crack, and not as direct.

I guess if you have your Screened BB on a flat sealed surface and tape the tray slot you may be fine.
I'm not a fan. empirically those hives die first.

10-14% better is one mite cycle. It seems to me the only mites that fall are the ones loosing their grip, or when the dead bee lands on the screen they fall thru. So then are you screeners not selecting for mites with a better grip? 

GG


----------



## GregB (Dec 26, 2017)

Gray Goose said:


> It seems to me the only mites that fall are the ones loosing their grip, or when the dead bee lands on the screen they fall thru. So then are you screeners not selecting for mites with a better grip?


Based on my observations, a solid bottom works just as well in the mite department IF it is configured like so.
Given 2-3 inch deep dumpster zone, mites don't have many chances to get out of it.
Especially if ants have access to this area.


----------



## Litsinger (Jun 14, 2018)

Gray Goose said:


> I guess if you have your Screened BB on a flat sealed surface and tape the tray slot you may be fine.


GG:

I think you are on target here. When researchers are talking about screened bottom boards these days, I do not believe that they are talking about open mesh floors but rather having a means to conduct diagnostic testing relative to mite fall, etc. For example, if you watch starting at about 2:25 - 3:25 of the following video from the UoG Low Varroa Growth Program, you will see a demonstration of how they are using screened bottom boards with inserts to assess mite fall:






For my part, I employ a modified screened bottom board which is equipped with a Freeman beetle tray that doubles as a mite drop board and remains in place all season long. I happen to be assembling some now, so I have attached a few photos. I also included a couple photos of how I affix the slatted racks as an aside relative to a recent conversation we had on this topic.


----------



## kilocharlie (Dec 27, 2010)

Thank you, Graham. I notice that it is readily available, but have not seen much discussion about using malathion to fight mites. That is probably why


----------



## Gray Goose (Sep 4, 2018)

Litsinger said:


> GG:
> 
> I think you are on target here. When researchers are talking about screened bottom boards these days, I do not believe that they are talking about open mesh floors but rather having a means to conduct diagnostic testing relative to mite fall, etc. For example, if you watch starting at about 2:25 - 3:25 of the following video from the UoG Low Varroa Growth Program, you will see a demonstration of how they are using screened bottom boards with inserts to assess mite fall:
> 
> ...


so looks like your new woodenware is 8F
you will like the slatted racks IMO, nice air and cluster space in hive.

pick out your paint yet?
I found a fairly reasonable paint and the "restore" a place to re sell construction goods.
Was "fence paint" 

I made the lids and painted them yesterday for the 3 new hives.
Solid BB, Slated rack goose style, 2 deep, 1 medium, lid.
going to use cloth inner cover.
mayhap I get pics.

GG


----------



## Litsinger (Jun 14, 2018)

Gray Goose said:


> you will like the slatted racks IMO, nice air and cluster space in hive.


Thanks, GG. I've standardized around 8F equipment and slatted racks as the standard set-up for production hives. Had I to do it over again, I might have gone with 10F but I sort of like the philosophy of aging in-place.

I must confess that I am a bit of a paint snob- I started off using Sherwin-Williams acrylic and have had great luck with it, so I am hesitant to go away from it. That said, I think you're smart to utilize the paint seconds. Another thing I had never thought of was painting hive bodies in any color other than white. Then I read a recent post by Ms. Dorothey Morgan in our recent Kentucky Beelines publication (with photo attached):

_'I have found by painting hives a warm color (not white) that on a sunny day the inside of the hive will warm enough for the cluster to break and retrieve food and bring it back to the cluster. This easy step can save many of your hives.'_

I would have thought this might be an o.k. idea in places further North, but if it is working for her around here, it is certainly something to think of.

I'll look forward to seeing your photos- I am intrigued by the cloth inner cover idea- it intuitively makes a lot of sense to me. Are you going with canvas?


----------



## TysonHoneyFarm (Dec 30, 2014)

Vance G said:


> Screened bottom boards fall into the Angel Farts category in varroa control. The only thing they do is reduce area where bees can raise brood. Reducing brood does reduce total varroa output but is hardly a laudable solution to varroa infestation. They may do less harm in the steamy south but do not pass the giggle test in my cold northern location.


While I may be in the south so not near the winter you have up north. I use screened bottoms, not for varroa control but more for ventilation mostly in winter I leave the entrance wide open. And also so hive trash falls to the ground and bees don't have to waste time clearing it out. While I have heard all the cons about screened bottoms keeping queens from laying to the bottom of the frame. In my experience of running them exclusively for about 12 years. I have hardly ever seen this happen except on nucleus colonies in early spring. But I do plan pin doing a comparison with solid bottoms this year mainly because I hate to build the screened bottoms. This is just my experience in SW Arkansas I'm sure it's different in other areas.


----------



## Gray Goose (Sep 4, 2018)

Litsinger said:


> Thanks, GG. I've standardized around 8F equipment and slatted racks as the standard set-up for production hives. Had I to do it over again, I might have gone with 10F but I sort of like the philosophy of aging in-place.
> 
> I must confess that I am a bit of a paint snob- I started off using Sherwin-Williams acrylic and have had great luck with it, so I am hesitant to go away from it. That said, I think you're smart to utilize the paint seconds. Another thing I had never thought of was painting hive bodies in any color other than white. Then I read a recent post by Ms. Dorothey Morgan in our recent Kentucky Beelines publication (with photo attached):
> 
> ...


here are some pics of the 2 recent built hives.



























first is the bottoms, the lids and the slatted racks.
the second is 6 deeps and 3 mediums, last of the handles are on top of the slatted rack in pic 1
3rd is the Bottom board, coated with Propolis tincture
in the back corner is the "new" twist I am trying, A 1 bee width opening in the corner, any wind will create a slight air flow, which with venturi effect will stir the inside air to allow exchange.
4th is the lid, I happened to have some 14 inch boards and made lids with only the ends, migratory covers I think.

those 3 make 10 more for next winter. Just in case I have increase this year.

the inner cover will be the 8 oz duck cloth


----------



## Litsinger (Jun 14, 2018)

Gray Goose said:


> here are some pics of the 2 recent built hives.


Nice, GG. I assume all the lumber came from off your place?

I'm sold on the propolis tincture too (courtesy of @GregB). If nothing else, it sure smells good.

Don't forget that all our Spring nucs are going to take, so you're going to need all those boxes .


----------



## Gray Goose (Sep 4, 2018)

Litsinger said:


> Nice, GG. I assume all the lumber came from off your place?
> 
> I'm sold on the propolis tincture too (courtesy of @GregB). If nothing else, it sure smells good.
> 
> Don't forget that all our Spring nucs are going to take, so you're going to need all those boxes .


trying to get prepared for that trip home with , bigger boxes needed.


GG


----------

