Bee shaker

I wrote about counting mites recently. Even if I don’t, others do, and sometimes it gives information that may help you make a decision.

John Harbo mentioned when he lectured in Sweden in May 2013 that before choosing the method for selecting for varroa resistance at the lab in Baton Rouge in the 1990th, their statistician helped them evaluate different methods. Their conclusion was that selecting for infertility of mites, then called SMR, later VSH, was the best method. Using one-drone insemination on 43 queens from a source of collected survivors they started the work in 1995 and in 1998 the goal was achieved. Impressing to say the least. Why havn’t this result have had more impact during the years. The queens produced at that early stage in the process were so inbred they were superceded quickly and the honeyproduction was low. They got bad reputation and beekeepers didn’t understand how to use the resistant queens fully. The situation today is very different.

One selection method among those not choosen, was checking the mite population. Though this method is still promoted buy others and used as well. Maybe because some have found it valuable in this matter. And most of us are living in free countries and can do our own choice.

Another reason for doing mite counts is for making a desicion if or when mite tretament is needed. In US it’s been said the threshold for treating is 3 mites per 100 bees in an alcohol wash. Some say this number seems to have to be lowered as viruses are worse nowadays. That probably is valid for all those moving their bees to almond pollination, where the bees share the latest in pathogens, pests and pesticides. Maybe all this treatment used during the years has forced the mites to answer with reproducing quicker in that they stay in the phoretic stage (on the bees and not in the brood) for a shorter period before they enter brood cells again.

Anyway, my small scale beekeeper friend cooperating with me, Leif Stromberg, quite on his own with his bees but not totally; he has 15 colonies, use the threshold 5 mites per 100 bees for treating, in october only when there’s no brood. It’s a help for deciding if he shall trickle oxalic acid. He trickled 4 colonies in autumn 2013. His winter losses are small. He lives 100 km north of me and cooperates there with Bjorn Lagerman, 90 colonies, with basically the same stock of bees as me too. His story could be told in another post.

HDRtist Pro Rendering - Pouring bees in the bee shaker (pictures used with the kind permission of Randy Oliver).

Leif has compared natural dropping of dead mites through the season and this late alcohol wash. And there is actually very little correlation, if any. His conclusion is that natural downfall of mites is of no practical value to get a good idea of a mite population having an impact on the bee colony, at least when it comes to his bees (he gets a couple of virgin queens from me every second year or so) that apparently has some resistance to varroa. Randy Oliver has also lost faith in the natural mite drop method for determining the actual mite population.

Shaker2 After shaking for 1-2 minutes, turn the shaker around…

Randy Oliver uses a very practical way of alcohol wash, the bee shaker. For some time John Williamson produced it for sale, but doesn’t anymore. As far as I know, no one does at the moment. But it takes 5 minutes to make one yourself from two suitable cans with plastic lids and a piece of beetight netting that let through mites. Follow the instruction here:

Shaker3 … and count the mites

Struggle for resistant bees

STr Apiary smal

Yes, do struggle for resistant bees. Don’t just talk about it! Or say an easy no, it’s impossible, or an easy yes: ”Just do like I tell you.”  Tell me your success story. I tell you mine, well a part of it here.

1989 I went to Kenya and got breeding material from Apis mellifera monticola, the mountain bee. Yes, that was a good longshot. I don’t regret it. In 2000 I visted Lusby’s in Arizona and got hooked on smaller more natural cellsize. I don’t regret that either, even if I’m not sure how much it helps against varroa mites. It’s more natural and bees don’t perform worse with it, in any way. Natural selection benefits survival and it has selected for small cell size in brood area at least. There are obvious benefits like rapid spring build up.

I thought I had regressed my bees down to 4.9 mm cell size when varroa hit hard in 2008. The mites arrived a couple of years before to my area. But it turned out when I analyzed the dead colonies following that many had too many badly drawn combs.

STr Wrong comb Quite some combs looked like this, but they are gone now.

My plan A was that I wouldn’t need any treatment against the mite as I had African genetics in my bees and they were small cell. But a gut feeling told me to have a plan B if something should go terribly wrong. And it did

I didn’t want to use acids as my conclusion was, wrong or correct, that formic is to hard at the bees and dangerous for me. Oxalic put me also in danger as I can’t smell oxalic fumes, but formic it’s no problem smelling. Inner organs and skin you know. I want to keep them going. Nerve poisons like Fluvalinate and organic phosphates like Coumaphos, cancerogenic like Amitraz and it’s breakdowns. My gut said no. The only thing left was Thymol. Yes it kills a lot of microbes as well. But it’s a spice and you find somewhat in basswood honey.

My conclusion was that it’s better with some living colonies than all dead. You can select the best among the living. It’s no use among the dead. Was it possible to use less and less Thymol? The bees were so overhelmed with DWV (Deformed Wing Virus) and mites that no one would have been left of my 250 colonies in 2008. Well, maybe 10 % when autumn 2009 came,…. When spring came 2009 I had lost 50 %. I got a feeling the mites were filled with viruses when coming to the area. I lost several tens of thousands of dollars in left out income in struggle for more resistant bees. But I didn’t want to get caught in the chemical trap.

Thymol for susceptible bees you need minimum two trays with 25 g thymol each (50 g in total). 10-14 days apart. If only treatment normally too little in a year. For some years now 80 % of my bee colonies have been treated. I have used in average10-15 g of thymol a year on my colonies (all included then). A few needed 35-40 g. They have of coursed got new queens.

Str Thymol Small One piece of Thymol with 4-5 grams on a struggling colony in spring.

I now winter about 170 colonies. I have lost 15 % of the colonies the last winters. (But this winter seems to end much better.) 30 % of those that survive have been small, got treated and new queens and gave no honey. The average honeycrop, including the 15 and 30 % mentioned has been about 50 pounds (25 kg). The top colony almost every year reach 400 pounds. The apiaries differ a lot in yielding nectar.

Str Thymol Strong 15 g of Thymol on a strong colony in summer, with supers above the excluder. Few cases.

I treat only (and I do it mostly right away regardless when it is in the season) when I see a couple of deformed winged bees outside or inside the hive. The hives are equipped with a board half a meter in square in front of the entrance for easier seeing what the bees are dragging out of the hive. Mostly the colonies are being treated in spring or in late summer. Those few treated with honey supers on get the honey ventilated in zig-zag stacks of supers in a warm room with a fan going for at least a week before extracting. To vent out thymol smell.

There’s only my stock of bees in quite a big central area where I have my bees. In the outer areas my bees dominate. I keep about 10 colonies in each apiary and they are as close as I can find places for them. 1 mile (1.5 km) between them would be ideal. The queens are mated in the apiaries.

Last year (2013) I used thymol on 50 % of my bees. In average I used 5 g thymol, all colonies included. For breeders I use colonies that havn’t been treated for at least the two previous years. The number of breeder candidates has increased for every year. Last year I started to check the VSH trait. I think this will make it possible to check eventual breeders a year earlier then before.

The VSH tests I did last year on my 5 breeders gave the following results: 1) 50 %, 2) 40 %, 3) not possible as I didn’t find one single mite in the brood, 4) not possible as the four year old queen died of age early (I just was able to make one graft), 5) not possible as the three year old queen produced more than 50 % drone brood.

Str Good Apiary A good apiary. Bee escapes on. Next visit the bee blower rids the boxes from the remaining bees. It will be when yo take 4 boxes like from the colony to the right. (That’s at least 150 pounds of honey).

I don’t count mites

I know it can be beneficial to count mites. But I don’t have the time. But those colonies I check for VSH, they will get figures enough to get the infection rate for mites in brood. (But I just check some.) Sometimes I’ve heard that two thirds of the mites are in the brood. If that’s correct then the infection rate on bees (phoretic mites) is half of that.

Many use the infection rate increase from one time till some time later to get a figure of resistance, saying the colony with lowest increase is more resistant. That might be true, but infection rate is dependent on other factors then mite reproduction success in the colony, such as reinvasion of different causes.

So I use the lazy method checking for signs of virus (DWV), thus also selecting for virus resistance. Then when I see this, I treat, with thymol, just the colony (-ies) showing virus. Over the years the number is decreasing and the amount of thymol is decreasing also, telling me this is a method that works.

Spritb For alcohol wash I recommend taking bees in the broodnest third frame from the back or one side to avoid including the queen in the alcohol and getting away from the entrance.

If you count mites, the most accurate method I think is alcohol wash, of as many bees you can afford (100-300 bees) when the colony has no brood (or as little brood as possible).

Sprit2b Shake the bottle with bees and alcohol strongly for a minute to loosen the mites. Pour them on a double sieve. Flush water on the bees strongly and count the mites in the second sieve. Also count the bees in the first sieve.

But beware where you take the sample. Don’t take it on bees close to the entrance. Mites are fewer there according to findings of Thomas Kober (personal information). So how do you avoid entrance bees if you have all the combs sitting with their edges towards the entrance? The best place maybe is in the broodnest but as far away from the entrance as possible, box two or even three maybe. I havn’t seen a paper on where the best place is. Maybe you have?

This is another reason I don’t count mites, the uncertanity if the density of mites is the same in different places in the hive.