postmortems & mysteries

Colony postmortem #2


Here’s another chance to help a fellow beekeeper. Chris, a first-year beekeeper in Georgia, lost one of his two hives back in February. In order to figure out what went wrong, Chris did a detailed postmortem and recorded his notes for you to review.

I already gave Chris several ideas of my own, but both of us would love to hear what you think. Postmortems are great “thought exercises” and I always learn something by trying to sort through the clues.

Pencils ready! You may begin.

Colony Postmortem by Chris Grey

Acworth, Georgia

The history of the hive

I knew the hive was low on honey going into the winter last year and I was fully prepared to feed the bees through the winter with sugar. I started by putting sugar cakes on the rails, but they were making such a mess with the sugar letting it drop through the hive, through the screened bottom board, and onto the ground, I decided I’d try something different, a tray.

Somewhere around December, I figured out they didn’t like/couldn’t eat dry sugar. So I started wetting the sugar in the dish. However I was noticing them in the dish less and less as the outside temps got lower and lower. So I reluctantly pulled chunks out of the dish and put them on the rails and found they would eat that. Before I left for a 4-day vacation, I pulled out a few chunks and left them on the rails. One of the chunks I pulled out was a particularly pink chunk . . . pink from a crushed salt lick I put in the sugar mix.

Neither hive has shown a Varroa infestation since the summer when I was inadvertently raising a ton of drones (long story, not relevant here). There are Varroa that drop onto the board, but not nearly enough for me to be alarmed. At the end of the fall, I was averaging about 10-15 drop in a week. As little as the hives had, the hive that died curiously started having only one or two Varroa drop in a week period.

I had noted that both hive populations were growing from only covering about 2 frames to 4 frames. That increase happened through early January. However the dead hive seemed to stall. It never got smaller, but it didn’t seem to maintain the same pace of growth that the other hive did towards the end of January. Problem with the queen?

The other noteworthy thing about the dead hive is for weeks before it collapsed, the front landing board always had more dead carcasses than the hive that’s alive. I don’t know if that means anything or not. The live-hive would usually didn’t have any, but if it did, there were only 1 or 2. The dead hive would consistently have 8-10 carcasses on the front landing board. I’d clean them off and more would be there a few days later. Best I can figure is that hive just had lazier undertakers that didn’t drag the carcasses further away.

The findings of the postmortem

I went out of town for four days and the hive died sometime while I was gone. So I don’t know exactly how long before I got back. The first thing that was obvious was dysentery all over the walls of the top (empty) super and on the frame tops. This was unusual for either hive so it stood out to me immediately as a clue.

Digging into the hive, I found roughly a dozen capped brood in varying age from white to nearly ready to emerge. I expected far more brood than this. I didn’t notice any eggs or uncapped larvae. They may have been there and I just missed them. I do know what uncapped brood and egg look like in a cell so I would think if it was there, I would’ve noticed it. Again, weak queen?

Each frame had a few bees either on the frame or head-first in the cells. Most of the bees head-first in the cells were on end-frames. I did notice granules of sugar inside some of the cells. It wasn’t packed; just on the walls like someone had taken a salt shaker to the frame. I’m guessing it’s where sugar had gotten into the cells as it fell through the hive from being eaten by bees above.

There was NO honey in the hive, but that was no surprise given I knew they were light on stores going into the winter. What had been concerning all winter is their intake of sugar wasn’t nearly what I would’ve expected either. They were eating the sugar, but not nearly as fast as I assumed they should. Although the hive that’s still alive wasn’t eating theirs any faster and was equally light on stores last fall and they flourished even while the other hive was alive.

Once got to the bottom of the hive, I found all the bees lying on the screened bottom board. Some of the carcasses had sugar on their bodies. The pile seemed damp. I’m not sure if that was just from the weather and sitting on the bottom screen (of which did have the white board under it) or if that was a clue that the salt in their feed had something to do with their demise (salt being hygroscopic).

None of the debris had any signs of Varroa that I could see. But that wasn’t a surprise since very little had been dropping and very little was on the board after they were dead (no more than 3-4 on the entire board). I never found the queen in the debris, but I admit I didn’t look as hard as maybe I should have. I also noted a bald faced hornet in the debris, but I haven’t seen them hovering around the hives since mid-fall. My guess is this was a hornet that made its way into the hive but was successfully attacked by the hive back last year. While it’s possible, I highly doubt it had anything to do with the hive’s collapse…not at this point in the year.

My theories

1. The pink sugar had too much salt in it and the bees succumbed to basically salt poisoning which gave them dysentery, then death.

2. The colony just starved. Despite having food within their reach, they just weren’t taking it as fast as they actually needed it.

Since the collapse, I started feeding the other hive sugar water from jars again. I mixed the sugar up with 3 cups in a quart-size jar and filled the jars with hot water to the top. The bees immediately started taking the water and continued to until night when the temps dropped and they all joined the cluster. So now seeing they were hungry for sugar, I moved the jar to inside the hive so they could take from it 24-7…and they have. In the past 2 weeks, they’ve probably consumed more sugar than they have since early December. Also in these past two weeks their population has exploded. In a 10 frame box, they are now covering roughly 7 frames. And their Varroa counts are also quite low. As of this afternoon, I counted 3 Varroa on the board and the board was cleaned last week.

What I’ve taken from this

1. Skip on the salt-lick in the sugar. I’ll set a lick outside somewhere and see if they want it. That way they can opt into consuming it vs having to eat it in order to get sugar.

2. Feed the bees via a jar inside the hives all winter. With the jar inside the hive sitting right above the cluster, it stays warm enough for them to drink from AND not nearly cold enough to freeze. Add to that, I did some research and found that sucrose lowers water’s freezing point. The more sucrose that is added to the water, the lower the freezing point of the mix. At saturation, the freezing point is somewhere near 0°F…well below the coldest of temps we ever get here and certainly a lot lower than should be inside the hive near the cluster. So there’s no reason for me to fear the water freezing, bursting the jar, and raining cold water down onto the bees. My fear of this was the whole reason I didn’t feed my hives this way in the 1st place. Had I fed them this way instead of with the sugar cakes, I’d possibly still have 2 hives.

Thoughts, questions, theories, suggestions?

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  • I agree that salt was likely an unnecessary addition to the syrup feed. However, rather than leaving syrup on all winter, you have the option of leaving fondant. You will have fewer issues with condensation that way, if you have any concerns about condensation in your climate. The detail that concerns me most is the dysentery all over the top bars and walls. That makes me wonder about Nosema. I have access to an Iotron facility and would have all the equipment sterilized before reusing. If you do not have such a facility, consider disinfecting that equipment (acetic acid vapour is one option) or discarding it to ensure your new bees are not infected with Nosema spores in the old equipment. I don’t know what your Varroa control approach is, but if it did not include a late summer/midwinter treatment, it is possible Varroa were a problem. Drop rates are not always indicative of the level of infestation.

  • Chris, I have a very similar situation. I went into the winter with 5 hives. I had tried to blend some bees with the colony I lost. They were not my weakest hive but far from the strongest. I fed some sugar cakes and some grease patties. I think I got my grease patty recipe from Honey Bee Suite. They possibly were stressed from the blending process that wasn’t working in my case. I had bees die with honey within an inch. The lower bees left, or whatever. No queen found. Very few actual bees in the lower chamber. The upper chamber was doomed at that point. The weather was cold and they had no queen. They died in the cluster. I don’t think my problem was the pink patty. I put the same in every hive the same day. I doubt you gave them too much salt. More recently I made some plywood dividers to go just below my quilts and they hold 6 pints of sugar water. I use a medium super around the jars. I have 6 pints of water with 2 additional openings for ventilation. I cover the vents to keep the bees out of this area. With all that said I am very close to the same thing you have experienced. I think it is not uncommon for bees to die in the winter with capped honey within an inch from the cluster. I hope someone can help you because I think I had possibly the same problem. Keep the comb and treat another colony.

  • I can’t help thinking the salt was the culprit. I’ve heard bees will take salt, but that’s during warmer months, and they get their sugar elsewhere. Since salt is, as he mentioned, hygroscopic, and since bees use what little condensation they find in the hive to obtain moisture to dissolve solid sugar (or they wouldn’t be able to eat it), I’m thinking that the salt intake caused dehydration, which in turn made the sugar inedible. That might not have been a problem if there were any remaining honey stores, but since there were not, they simply starved.

    An additional clue: a number of bees died with their heads in the cells, which suggests they were trying to reach nutrition other than the sugar blocks at the time of death. Again, this suggests to me that for some reason they couldn’t eat the sugar, and the salt seems a reasonable suspect.

    I’m not sure how the dysentery would figure into the equation, although I suppose it’s possible that the salt simply upset their stomachs. In any case, I’m curious what made him want to put a salt lick into the sugar at all? Is there a precedent for that?

      • Take it with a grain of salt (no pun intended) though, I’m still a first-year beekeeper 🙂 In any case, I think if it was the salt, the problem wasn’t salt so much as mixing it with the sugar. If it’s mixed with the sugar, they can’t eat without also eating salt.

  • About 10 years of education in a few paragraphs. Thanks so much, but still sorry for the loss. I lost all my bees the exact same way last year.

  • I am a new beekeeper and just over wintered my first 11 hives (I started out with 8 nucs last spring) all 11 are doing great so far. I used dry sugar, syrup in baggies, a sugar water paste and a pollen patty. I wanted to cover all my bases. In all my feeders except 3 hives that didn’t have feeders at all. I only had 8 feeders. I chose those 3 because they had the most honey. All went into winter with honey stores but 2 were over wintered in 2 mediums instead of 3. (I did a late split) My temps got down to -30C (BC Canada) this winter. I never used salt? I did not know that salt was something the bees needed. I did some things simpler to you except the salt. Being as inexperienced as I am I think maybe it was the salt?

    • Irene,

      All animals need salt, but bees are small so they don’t need much. Honey bees usually get all the salt they need from their outdoor water sources; those puddles and slow-moving streams all have some amount of salt in them.

      I frequently see mineral salt added to grease patties as a source of micronutrients. Mineral salt is high in micronutrients as compared to table salt which has virtually none. The thing about grease patties is you don’t give them very much and, of that, they don’t eat very much. This type of feeding is known as “free choice feeding” because if they have a craving for salt, they are free to eat some, but they don’t have to eat it since it isn’t their primary food source.

      According to West Virginia University, salt in grease patties helps to keep the bees from seeking other sources, such as barnyard urine.

      I’ve never heard of putting salt in the sugar supply except in infinitesimally small amounts (for example, 1 teaspoon salt in 10 pounds of sugar) so I’m inclined to agree with you that the salt is suspicious.

  • My only comment is more of a question. I’m not familiar with the practice of feeding bees salt. Maybe because I live in the inland Pacific Northwest? What purpose does feeding salt serve?

  • A few thoughts.

    I know feeding dry sugar is popular in the US, but here in the UK it’s rarely done. I tried it on four of my hives this autumn and won’t bother again – they hardly touched it. You’d have been better off feeding a 2:1 strength sugar: water solution in the early autumn, which they can store in place of honey. And then for top-up feeding in winter, place candy/fondant (you can buy this from bee suppliers or make your own) on top of the crown board or directly on top of the frames. The sugar crystals are harder work for the bees to feed from, whereas the candy is soft.

    When you mentioned that the colony stalled, I wondered about nosema, which is invisible and the only obvious symptom is a failure to thrive and grow. Then you mentioned dysentery, which helps spread nosema if it is present. I would use new brood frames for your next colony, destroy the old frames. Aim to replace the brood frames once a year.

    I think the bees starved too, but I’m sure the high varroa count in the summer and possibly nosema also weakened them.

  • Chris sorry for the loss, each season brings new challenges, but your attention to detail will turn the challenges into great learning opportunities and give you a lot of insight. BTW, I’m slightly further south (FL Panhandle) but always use syrup through the winter.

  • Chris,

    Welcome to beekeeping. It is a great hobby, I assume that you just got started, and sometimes you stumble. Just pick yourself up, assess what went wrong (as you are currently doing and keep on truck’n). If you are just getting started I strongly recommend that you join a beekeeping club, attend one or more of their bee schools, and get a mentor from within the club.

    IMHO most beekeeping problems are directly or indirectly related to Varroa mites. I’m a treatment free/IPM type of guy so I have my share of problems too.

    I’ll take sort of a random walk down through your postmortem assessment:


    You should have started feeding the bees 2:1 sugar syrup, probably in September, and had the hive weight up to around 150 pounds total before cold weather set in. Solid sugar is an emergency form of food and should not be used for normal feeding. Yes, I think that you probably OD’ed your bees with the crushed salt lick. The application of salt in bee food is a pretty advanced thing in beekeeping and I don’t think that you should be doing it. However, I do add a very small “pinch” of electrolyte to five gallons of 2:1 or 1:1 sugar syrup when I feed in the fall and again when I feed in the spring. I doubt that your mite count was as low as you thought, the drop board is the least reliable method, but at least it gives you an idea. A powdered sugar roll is more reliable and not too difficult to do (see the Randy Oliver reference below). It sounds like you may have gotten a late start in the year with a package (?) of bees or may have not gotten them from a reliable source, because they should have built up to a stronger colony by wintertime and not have been increasing so much in December/January. A big factor in winter survival is that there needs to be a large enough mass of bees to maintain the core of the cluster at around 97 degrees F. They will survive well below freezing ambient temperature if there is a sufficient mass. Your queen may have already been dead at this point as is evidenced by the number of dead bees being hauled out of the hive. Older bees were dying of old age or mites.


    The dysentery concept (which is indicative of disease) does not sound good and you might want to scrub up your woodenware real well before you consider reusing it. What was the deal with an “empty super” at the top of the hive? Was that to cover the sugar food supply? If so that is too much empty volume in the hive in the winter. You can make a “super” that is 2-4 inches high as a feeding rim. (In other words, keep the winter volume inside the hive to a minimum.)

    I think that the queen was dead and the number of nurse bees was minimal and unable to tend to the brood which died. Dead bees head first in cells is indicative of starvation. The white “granules” especially if around the top edge of the cells, may be Varroa poop. No honey in the hive of course is not a good sign. In the future you need to ensure that your colonies have sufficient weight going into winter. Damp dead bees indicates that there was insufficient ventilation within the hive. I keep bees in a very arid and cold environment and I have an open screened bottom board, a lower entry and an upper entry year round and no moisture problems within the hive. I’m sure that you are familiar with the expression: “wet bees are dead bees.” Maybe remove your white board in the future.


    I agree, I think that the salt was not a good thing. You need to get the hive weight up to specs before the winter sets in and to periodically check and emergency feed during the winter if necessary. If feeding sugar syrup, feed 2:1 in the fall and feed 1:1 in the spring. It sounds like you entering the spring build up already. Bees will generally not take liquid feed at temperatures below about 55 degrees F and you are correct, feeding inside the hive reduces the likelihood of robbing. If you are feeding liquid with an inverted jar with fine holes in the lid, both an increase in temperature and/or a change in barometric pressure will cause it to leak.

    Here are some references that may be helpful to you:

    o Bee Forum (General info read daily)
    o (Read Rusty’s periodic articles)
    o All about beekeeping
    o Randy Oliver

    Read, Practice, & do better.


    I said earlier that I had fed my bees salt and doubted this was the problem. The above link is a recipe that Rusty put on here earlier. This is how I fed my bees salt except I had to reduce the recipe so the salt was reduced accordingly. Animals are smarter than humans. Humans will eat something until it kills them. animals will usually take what they need and move to something else. This is how you give nutrients to your cattle. Put out for them and they take what they need. I have been around cattle all my life and I am probably the oldest person on this site that is concerned about bees. The hive I lost this winter appeared to have absconded in December! Why would they do that? Stress? I don’t think they died due to the amazingly low number of dead bees. I fed the same patties to my other 4 hives and they are still going. I checked their sugar water yesterday and they have taken a very small amount of it. I have patties on the top bars. I have 9:1 sugar cakes I made in the late fall. They have taken a small amount of this. So I have cakes, hard 2:1 patties and grease patties in their hive plus the 1:1 sugar water available. What went wrong? What do they eat? They DO like honey best of course.

  • I have no advice or theories, only this personal observation:

    Whenever I discover dysentery inside the hive — what I call poop all over the place — it always means the queen is dead and the surviving bees have lost their minds and all sense of purpose. They forget how to be bees. The queen is dead from being old, dead from the stress of having a mouse or shrew in the hive, but dead at a time of year when the colony can’t requeen (fall or winter) and subsequently the bees don’t know what to do with themselves, so they go nuts and poop wherever they feel like it and don’t bother cleaning up after themselves. Again, only my personal interpretation of that particular situation. As soon as I see poop inside the hive, I know they’re goners and, if I can, I combine the surviving bees with another colony.

    Other minor thoughts… I’ve never heard of giving honey bees a salt supplement. I’ve been feeding my bees dry sugar for the past three years (in a very wet climate) and although they may clear some of it away, when they run out of honey, they have no problem eating it. UNLESS there’s a mouse or a shrew inside the hive and they’re stressed. Then — my personal interpretation again — the bees go crazy and forget to eat and do things they would normally do to stay alive.

    • Phillip,

      Interesting observation. I’ve only seen really bad dysentery in one of my hives twice, and both times the queen was a goner.

    • I’ve never heard that, but that would certainly fit my scenario since based on how little brood was in the hive, it certainly looked like the queen was either dead or hadn’t been laying in some time.

    • Phillip, You have The right answer covered. Only one comment. About salt, bees do use salt to cure honey. However, I would only supply if you are near livestock. Then put out a salt block, not regular table salt. (sea salt)

  • Thanks for all the thoughts and theories. This 1st year was definitely a learning experience and plenty for me to work with and adjust for this year.

    As discussed, I won’t be adding salt to sugar ever again. If I give them salt, it’ll be separate from the sugar so it isn’t forced on them.

    Add to this, I did not build up their stores in the fall. At the time, I just assumed leaving sugar in the hive would be enough. But experience proved that not the case. So this year, I’ll be pushing 2:1 on them probably around September to help them build up.

    Another thing I’m going to do is when I harvest a super from the hive, I won’t be putting it back on the hive. I know now there’s plenty of room in the brood chamber frames to store nectar at the end of the season and the sugar water I give them since the queen is reducing the population, so there will be more space to put stores. And as was mentioned, this reduces the internal volume of the hive.

    The one thing I really did like was having the empty super on top. It gave me an easy way to place jars in on the hive and get an idea of their welfare without exposing them to the wind when the top is open. Each time I opened the hive, the bees remained VERY calm…calm enough I didn’t need a suit. I personally found having the empty super on top quite useful and educational. Although the internal jar feeders might make jar swapping a little easier AND let me put multiple jars in the hive at once so I can go a week or so without having to worry if they have food.

    I have considered that it’s possible the open super causes cold air to come down on the hive. And next year, I might insulate the sides of the hive with 2″ R8 foam insulation to hold the heat in better. That wouldn’t be difficult to do.

    And even though I don’t believe my varroa content to be bad, I do have formic acid strips I’ll use to ensure I get any varroa that are in there. I’ll probably put those in mid March…a few weeks before I expect to do a split.

    Even though I feel like the dysentery was caused by the salt, I am willing to clean up the hive box and frames that got covered. What’s a safe disinfectant that won’t stick around in the wood and cause any bees to abscond?

  • We are still in the deep deep depths of winter here on the east coast. Snow and more snow, however my question is how much poop spots and dead bees in the snow is too much? Any thoughts on how to gauge this?

    • Marlene,

      Well, the more poop spots the better. That means the bees are healthy enough to wait for an opportune moment and go take care of business. As far as dead bees, I would expect to see hundreds, especially if it’s the accumulation of several days. Remember, in the spring and summer, you lose about 1000 bees a day, but you don’t notice. In the winter, you lose hundreds per day, but you do notice. That is just normal attrition.


    I have had a couple of lousy years with colony losses late fall, even early fall. Mite treatment always. Just cleaned up a dead colony that looked good a month ago. I prepared candy boards using metal wood-bound queen excluder and a 2-inch camp frame above with an exit hole. Above that a quilt with wood shavings. The colony was lying on the screened bottom board they all seemed to have died approximately same time. The bodies were not dried out and seemed fairly recent. My thought was that maybe they could not exit the top opening in large enough numbers. Thus I removed the board from the single live colony. This decision was based on my thinking about their exiting as I noted they (the live colony) are in the top box and seemed to have trouble getting past the excluder. The dead colony seemed healthy. There were some capped cells with near adults in them. But a very heavy hive lots of stores on hand. When emptying the bees onto the ground it looked like a nice medium size colony. These bees had wintered sucessfully two years. They were insulated colony wrap and surrounded by straw bales as a wind break. Treated with Mite away in mid august. I am thinking of feeding the others with syrup in bags since here in eastern SD we have had unseasonably warm temps mid and upper 40s to low 50s.

  • I “had” five strong hive’s going into winter 2023/2024 here in Ohio. Lots of bees were flying around on every warm day we have had so I open my strongest hive to evaluate on a warm spell and it was dead along with the other four. Plenty of honey left just piles of bees, obviously the bees flying around were wild bees just coming in for the feast. Every hive had strange white granular substance in the cells, I have never seen this before and no I didn’t feed sugar just their honey. I thought it might be granulated honey but it’s pure white and not the usual yellowish color of granulated honey. Contacted county apiary inspector and while he hasn’t been by to check hives yet he couldn’t identify what this stuff could be either. I wish I could post a picture but don’t know how to. Any thoughts?

    • Dwight,

      Based on your description, it sounds like you are seeing guanine deposits from varroa mites. The mites leave these white dropping on the walls of the cells, usually the uppermost walls, but it can be most anywhere inside the cell. If you would like me to take a look at your photo and post it here, you can email it to me at