Wondering why my 8 hives died last winter, I sent a 50 bees sample from each hive to the USDA for varroa/nosema/trachael testing and 200 bee aggregate sample to BVS for virus testing.
BVS came back with a very slight indication for Isreali paralysis virus. Dave at BVS said this was normal. No other virus' were detected. His comment was, 'your bees are very clean'.
The USDA came back with zero nosema and tracheal mites for every hive. They did come back postive for varroa in every hive. Some had between 5 and 7 varroa in each sample. I find that interesting because I hand picked each bee and looked at it and didn't see a varroa on a one.
The highest count (7) was on a May split. Two other swarms from the same parent hive as the split came back with 5 varroa. One of those hives even superseded in July. The other high count (6) was from an early August swarm that I believe to be feral.
The only treatments I have ever done for varroa was powdered sugar, which I did/do in mid September. The second year hives quickly crashed after the treatments. In hind sight I should have done it sooner, as the whole year was 3 weeks ahead of schedule, due to the early, warm spring.
Most of the hives were a combination of 5.4 mm cell, 4.9 mm cell, and natural foundation.
So my plan for this year is:
Two Georgia packages coming at the end of April. I am assuming they are coming with Italian queens. I have 6 new world carniolan queens coming at the end of June to split with. I also have 2 russian hybird packages coming in mid May. Hopefully these bees are more tolerant of varroa and other diseases.
I am going to phase out all 5.4 mm foundation through the year.
I am going to eliminate all lower entrances and use only upper entrances. This way I can keep the hive closer to the ground to utilize snow as insulation in the winter. Also it seems that most feral hives have their entrances higher up. So if a varroa falls, there won't be a bee walking by to jump back on.
I am going to put some Mann Lake PF 120s (medium) foundation in the outside frames of my deeps. The thought is to give them a place to build drone comb, but only on the outside bottom of the hive. As varroa are attracted to drones, then they can grow in the bottom of the hive and hopefully fall off upon hatching.
My last thoughts are ventilation. After watching JP remove so many cutouts in hot, hot New Orleans, I am thinking that summer ventilation is overrated. It seems the survivors that JP has been removing have had ZERO ventilation. I think I will stick with the SBB but keep the coroplast board in it all year. It does make it convenient to sample for varroa. I have been using the all season inner cover for ventilation, but I am thinking of leaving the insulation in all year also. I can't remember if it was Trot, or Grid, but someone made the comment that varroa do not like heat. So maybe all this ventilation has made the situation worse. I welcome comments on this thought, especially from JP, Hardwood, Bud and any other folks from the hot areas of the country.
For winter I think I will try some Bee Cozies or build a shed to store the hives in.
And if I get higher varroa counts, gosh I hate to say it, treat with MAQS and/or HopGuard. I really hate being a bee killer, rather than a beekeeper.
So that is the plan.
Thx.
Jay
p.s. I have had some feral bees coming to my deadouts, but they are reluctant to enter. I don't know if it is they don't know what a store bought hive is, or they don't like something. Some will lap up some of the honey that is running out of it, but more just land on the coroplast and rub their hind legs.
Jay, thanks for sharing your plan and the lab findings.
I like the sounds of your plan. I also feel that ventilation is over emphasized. How many feral trees have a screened bottom board? Michigan isn't all that hot to begin with!
I did find when I switched from bottom entrances to tops, my bearding went way down. The only downside I see with the top entrance might be more susceptibility to wax moths getting in on cool nights. I use top entrances.
It would be nice to get some good instrumentation data on a northern hive in the summer to see how much heat is gained from the sun. The incoming energy from the sun is about 100watts/sq foot, which could start to make bees feel like fries under the heat lamps at a fast food joint at times. I like your insulated top cover idea to keep some of that solar gain out in the summer. My plan is similar, less ventilation and more insulation :)
I have been wondering about the ventilation issue too. Feral hives generally aren't ventilated, whether in a tree or in the wall of a building. I don't think Warre' hives don't use ventilation and they are successful. My only fear of a top entrance is the inability to clear out the dead bees and pests from the floor, but I think I might try one anyway.
All bees ventilate the hive, some bees push/pull the air in on one side of the entrance, and another set of bees push/pull the air out of the hive on the opposite side of the entrance. Inside bees push the air to the upper (or Lower) reaches of the hive while bees on the other side of the hive move it back towards the entrance. This ventilation process, in it's early stages, is the beginning of bearding. As the population increases more bees beard to allow the freer movement of air by those bees so employed.
In a hive with ventilation used as part of their hive management plan, the bees still move the air around inside the hive but not by nearly as many bees, nor is mass bearding noted as the beekeeper planned ventilation does much of the work that the bees would otherwise have to do.
So is ventilation necessary, no. But it does make the hive more productive by allowing more bees to become foragers sooner and the nurse bees to remain on the frames (verses idle bearding time) tedning to brood and other hive house keeping.
Bees die from everything from old age to getting stuck on brood. Did you find dead Varroa on the bottom board? When I've lost them to Varroa there are typically thousands if not tens of thousands of dead Varroa on the bottom.
I am with M. Bush on this one . . . presence of mites doesn't mean that is what killed the hive. One of my most infested hives last year was my best honey producing hive and it overwintered again. And I get huge mite counts from this hive (>100/24 hours).
I also worry about the concept of using drone comb (if that is what your are mentioning below) as a method of mite removal without a specific plan to get rid of the drone brood before they are uncapped. I think the drone comb method of mite removal is well accepted as an effective means of lowering mite counts, but if you just let the drones hatch, then your are just setting up a great mite breeding ground and they won't just fall to the ground because they are on the bottom box, they will multiply at great speed and infest the rest of your hive.
Also just read a great thorough scientific article about varroa (Biology and control of Varroa destructor. Journal of invertebrate pathology. 2010;103:96-119. 24 pages, 450 references, 3 authors from 2 different University apiculture programs in Germany). Powdered sugar is minimally discussed as an effective control method ("in the field trial, low efficacy even if dusted every 2 weeks for 11 months . . ."). I would consider other control methods if you believe you have a serious mite problem, but I would think you would want to check your hives with proper drop counts to see where you are at.
Quote from: skflyfish on April 13, 2011, 08:54:56 PM
I am going to put some Mann Lake PF 120s (medium) foundation in the outside frames of my deeps. The thought is to give them a place to build drone comb, but only on the outside bottom of the hive. As varroa are attracted to drones, then they can grow in the bottom of the hive and hopefully fall off upon hatching.
@Brian,
Thanks for your insights into hive ventilation. I am still amazed at the lack of ventilation I have seen in cutouts JP has done. New Orleans is one hot, humid climate and the bees seem to survive well on their own. Ventilation to make a hive more productive makes sense.
@MB,
I put the coroplast boards back on in early September and saw less mites drop than the previous year. I really didn't think I had an issue, but used powdered sugar as a prophylactic. Before treating I would find maybe 40 mites after 3 days and double the amount after the powdered sugar. But if I extrapolate the numbers from the USDA, 7 mites in 50 would be 7,000 mites in a 50,000 bee hive, which is well over the threshold for a mite infestation. Whether that is a valid extrapolation, I will have to ask the USDA for clarification. I agree that some of the dead-outs could have been from lack of bee numbers or extended cold. But having 3 second year hives crash in October and the rest die in winter makes me wonder if it truly was varroa and not a 'perfect storm' of events.
@Tandemrx,
My thought was to put the drone brood where it is in feral hives, at the bottom, outer edge of the hive. Feral colonies that survive don't have someone drone trapping. But with that said, if I find higher numbers I can remove the medium frame from the deep and scrape off the drone brood that they built below and let them start again. Last year I decided to put a couple frames of foundationless super frames in some upper supers for cut comb honey. The ended up building drone comb and the queen crawled up 5 supers to fill it in. So my thought is to put the drone comb where it is naturally, or at least what I perceive to be naturally.
Thx all.
Jay
Is there any possibilty of chemical contamination, such as Pancho that the usda would not test for, or even with hold the verdict, just a thought..
@oliver,
That thought has crossed my mind. I live in a fairly rural area, but who knows if someone didn't spray the bees. They are in my back yard and I live on 2.5 acres, so they have plenty of room. But one never knows. One would want to think not, but there is always that doubt.
I am not familiar with Pancho and can't find anything on Google about it. Can you elaborate?
@bluebee,
I do like the idea of insulation over ventilation. A tree is much more constant in temps than our wooden ware.
Thx all.
I misspelled poncho--look at bayer poncho. its a seed treatment that is absorbed by the plant and kills insects..the thoughts a little scary not just for bees but for us, they just approved it for alfalfa, dairy cattle are big users, they say it does not get in the milk, corn syrup or any product, so why has several european countrys banned it ..
Quote from: oliver on April 15, 2011, 09:41:49 AM
I misspelled poncho--look at bayer poncho. its a seed treatment that is absorbed by the plant and kills insects..the thoughts a little scary not just for bees but for us, they just approved it for alfalfa, dairy cattle are big users, they say it does not get in the milk, corn syrup or any product, so why has several european countrys banned it ..
I have recently seen some seed corn commercials that say the seed is treated so the corn silk worms will not be on the corn. If that treatment will kill the worms seems to me it would harm bees trying to get pollen from the tassels.
Sterling, it sounds like you're talking about GM corm with a BT gene added in to express a naturally occurring soil BT toxin that specifically kills Lepidoptera larvae (butterfly/moth caterpillar pests). Here a link summarizing what it does.
http://www.ca.uky.edu/entomology/entfacts/ef130.asp (http://www.ca.uky.edu/entomology/entfacts/ef130.asp)
The BT toxin is supposedly target specific in that it kills caterpillars and does not harm the bees. Some beeks use BT to protect their supers from wax moths over winter.
Note: I said SUPPOSEDLY does not affect bees. I am not an expert on GMO technology nor have I done my homework on the subject.
Here is Bart Smith's response from the USDA in Beltsville, to the number of mites per sample of bees. Like I said, the white coroplast mite board never gave an indication that I had an issue with varroa.
You have some good questions below. Mite levels are sometimes expressed as the number of mites per 100 bees. 10 mites per 100 bees are considered quite high and immediate action (treatment) is required. Treatment is needed soon even at 5 mites per 100 and some of the folks writing in the bee journals say they don't like to see mite levels above 1 or 2 mites per 100 bees. So if your hive #4 sample was 50 bees, then you had 14 mites per 100 bees which likely contributed to the loss of the bees.
Jay
p.s. Bart has been a very pleasant person to work with as was Dave at BVS.
Many Northern beeks keep the insulation in place throughout the season 'except' during feeding. Personally I use both top (a notched inner cover with another 'empty' box over that) and bottom entrances, and SBB that I've learned to keep closed 'most' of the time. Some beeks also use the insulation/feed/vent box with 1 inch screened holes strategically placed in them, and swear by them.
I've only treated w/ powdered sugar once, a few years ago, and didn't like how my bees reacted so never did that again. I've only got a few frames left w/ foundation (for an emergency) since going to foundationless (and all mediums)three years ago and have never had any issues with varroa in any of my hives :).
thomas
I still think there is a problem with correlation vs. causation here. Yes, you had mites, yes, they may have contributed to hive loss, but just like CCD, trying to figure out the root cause is very difficult and they may have had nothing to do with hive loss.
Plus the measuring stick is rather biased in this case (selection bias :-\). You only looked at dead bees from a dead out hive . . . and the dead bees had mites at a certain level. That is different from measuring 100 live bees from a hive, or doing a mite drop check over a period of time from a functioning hive.
I am not saying that you shouldn't treat (I do, although many would say you shouldn't for various and sundry reasons), but I still think it is tough to say that the varroa mite was responsible for the hive deaths . . . never know if it couldn't have been a temperature shift, condensation problem, or a starvation process, or any of the multitude of reasons that we think kills hives (but seems like we never really know why).
I don't know that I ever get mite levels to below 1-2 per 100 even with treatment (depending on how you would count that - sugar roll test of 100 bees I guess as opposed to 24 hour drop).
Quote from: skflyfish on April 18, 2011, 10:59:55 AM
Here is Bart Smith's response from the USDA in Beltsville, to the number of mites per sample of bees. Like I said, the white coroplast mite board never gave an indication that I had an issue with varroa.
You have some good questions below. Mite levels are sometimes expressed as the number of mites per 100 bees. 10 mites per 100 bees are considered quite high and immediate action (treatment) is required. Treatment is needed soon even at 5 mites per 100 and some of the folks writing in the bee journals say they don't like to see mite levels above 1 or 2 mites per 100 bees. So if your hive #4 sample was 50 bees, then you had 14 mites per 100 bees which likely contributed to the loss of the bees.
Jay
p.s. Bart has been a very pleasant person to work with as was Dave at BVS.