Do you use Icing Sugar as part of your IPM?

[Neils]

Just out of interest.

I used to use it religiously as a low impact "non chemical" treatment but I've become less convinced that it is that effective, nor that is necessarily as low impact as often assumed, although This study and a few others suggests that concern is probably an over-reaction on my part.

Finding proper figures with regards to the efficacy of icing sugar knocking down mites seems harder to come by, lots of assertions that it is or isn't effective, but I'm not seeing a lot of hard evidence to back it up either way.

While I do keep icing sugar handy for other reasons i've tended in recent years to lean more towards drone brood culling if I feel that a mid season action is required and otherwise use Thymol post honey harvest and Oxalic Acid over winter.

So just wondering what other people's thoughts around it are.

[Pete L]

There is some research which say it is not effective, never even tried it myself, so cannot really say.

There is a bit below on RO's site, but expect you may of seen this Neil.

http://scientificbeekeeping.com/powd...y-work-part-1/
And this...
http://www.ibra.org.uk/articles/20090217_5

[Phil Moss]

It doesn't do anything to mites in the cells (over 80% of them IIRC at this time of night!), so it only has a small effect, removing some of the free living mites.

[Neils]

There is some research which say it is not effective, never even tried it myself, so cannot really say.

There is a bit below on RO's site, but expect you may of seen this Neil.

http://scientificbeekeeping.com/powd...y-work-part-1/
And this...
http://www.ibra.org.uk/articles/20090217_5

Funnily enough I was looking at another study on IBRA while trying to find that one, my google fu is obviously weak tonight.

It doesn't do anything to mites in the cells (over 80% of them IIRC at this time of night!), so it only has a small effect, removing some of the free living mites.

Somewhere I have a chart put together by one of the guys here where he worked out that a 10 day dusting cycle was optimal for getting the maximum number of phoretic mites in between brood cycles. But that still assumes that it is effective as a treatment.

I do think that it does have some place in an IPM scheme, one of the guys here uses it on samples of bees to knock mites off to guage the phoretic levels, but that uses a lot of icing sugar on bees in a honey jar.

[Phil Moss]

Somewhere I have a chart put together by one of the guys here where he worked out that a 10 day dusting cycle was optimal for getting the maximum number of phoretic mites in between brood cycles. But that still assumes that it is effective as a treatment.

I do think that it does have some place in an IPM scheme, one of the guys here uses it on samples of bees to knock mites off to guage the phoretic levels, but that uses a lot of icing sugar on bees in a honey jar.

Regular dusting will knock mites off, I had not heard of the 10 day cycle, I would forget it as a treatment, as you will still have mites in the cells.

The 'sugar roll test' puts bees and icing sugar in a honey jar with a piece of mesh as a lid, I rotate them for about a minute (they get remarkably warm), let sit for 2 minutes, (I then rotate again), shake the mites out through the mesh top.

2 other versions here:

http://entomology.unl.edu/beekpg/tid...0/btdjan00.htm
http://www.beelab.umn.edu/prod/group...set_317466.pdf

I use it to test for the pesence of varroa if a beekkeeper asks me to check for them, it will give you an indication of how many there are, but to have a 'proper' count to plan your control program, a mesh floor is best.

[Jon]

Phil, I know it is standard advice from FERA to count the mites which drop through the mesh floor over a number of days, take an average, then extrapolate the total mite number from that - but I have always found this to be very inaccurate. Sometimes I don't see a mite on the insert tray for months then treatment of some sort can produce several hundred overnight.

I agree with you that sugar dusting is of limited effectiveness. The particles in the sugar have to be below a certain size for maximum effectiveness and with a lot of icing sugar off the shelf the particles are too big.

This paper is interesting.

Journal of Apicultural Research 51(4): 367-368 (2012) © IBRA 2012
DOI 10.3896/IBRA.1.51.4.14

Revisiting powdered sugar for varroa control on
honey bees (Apis mellifera L.)
Jennifer A Berry1, Ohad Afik1,2, Maxcy P Nolan IV1 and Keith S Delaplane1

Dusting bees with powdered sugar has been examined as a remedial control for Varroa destructor Anderson and Trueman (varroa). Two modes of action have been proposed: one being that fine dust
impedes the locomotion of phoretic mites and induces them to fall off bees (Ramirez, 1994), and another being that dust induces a grooming response in bees that similarly dislodges mites (Macedo et al., 2002). When measured as a percentage of phoretic mites dislodged,
powdered sugar dusting has achieved experimental knock-down rates ranging from 77% (Aliano and Ellis, 2005) to more than 90% (Fakhimzadeh, 2001; Macedo et al., 2002), but a persistent problem has been translating these kinds of results into practical field applications.
The most comprehensive examination of powdered sugar as a
field-level varroa control was the work of Ellis et al. (2009) in Florida. These authors dusted the top bars of brood combs with powdered sugar every two weeks from April until the following February (11 months), compared numerous parameters of colony strength and varroa populations against a control group, and found no treatment effects on any parameter of interest. In spite of these negative, yet convincing results, we wanted to do a field study that: 1. exploited a brood-free period of the season when all mites are phoretic on adults and vulnerable to dust treatment (bee colonies in sub-tropical Florida are rarely brood-free); 2. compared more than one dust delivery method, and; 3. compared more than one treatment timing interval. We felt that these outstanding questions should be resolved before we abandon powdered sugar as a bee-safe (Fakhimzadeh, 2001) and chemical-free varroa control option.

[madasafish]

As a TBH keeper, sugar dusting is fraught with all sorts of logistical problems - in other words it's very difficult to do effectively. You ideally need a sugar puffer and access from below - or move every frame.

As a result I have never done it (nor oxalic)

[Phil Moss]

there is no reason why a TBH should not have top bars with spacers as in a national, with a canvas quilt on top. This has lots of advatages, such as sugar dusting (if you beivee in it!!!), oxalic, formic(!) etc.
I have 2 horizontal hives, like TBHs but well insulated etc, and they take deep frames with spacers. I can and do sometimes use top bars, but space them out.

[The Drone Ranger]

hi madasafish

can you use thymol on top bar hive ??

[madasafish]

Yes.

I use thymol plus beeswax mix impregnated strings hung between topbars*. Last year my mite drop was v low - tens. But the weather was so bad we had brood breaks in summer so hardly surprising. If I had been a proper natural beekeeper and not fed my bees I would have had none. I also add thymol emulsified mix to autumn feed to reduce nosema (?)..

Mite drop on my largest hive looks as if it may be highish - but I have just cleared it for a recount -if the weather allows - terrible forecast..

* bees do their best to eject them out of the hive!