Bee Health
Photos marked © Crown copyright are Courtesy of the: Animal and Plant Health Agency APHA.
Manage and prevent disease
BBKA assessment topics: the importance of cleanliness and apiary hygiene. Able to describe the appearance of EFB, AFB, Sac brood, and Chalkbrood. Be aware of Nosema and Acarine and their effect on the colony. Describe how to exclude mice and woodpeckers from hives in the winter. Be aware who to contact about bee disease and treatments (i.e. Regional Bee Inspector). Notifiable diseases are: EFB, AFB, Tropilaelaps
Reduce disease transmission by
washing your gloves and hive tool in a washing soda solution between inspections.
Quarantining swarms
not moving bits between apiaries and hives
Occasionally soaking “clean” kit in a bleach solution for 20 minutes.
Wear a newly laundered bee suit and clean boots when visiting someone else's apiary.
Avoid squashing bees - it spreads nosema
Put odd bits of wax somewhere safe for disposal later.
Regularly change brood combs (every 2-3 years).
Diseases and threats to bee health
Foulbrood, Colony Collapse Disorder, and inadequately treated varroa can cause heavy losses. Substantial unexplained annual colony losses (mercifully not a problem in the UK) and diseases that flare up when a colony is under stress can also cause losses. These include Nosema, Sac Brood, Paralytic syndromes, and Chalk Brood.
More serious is the ongoing threat posed by humans who accidental introduction of foreign bugs and viruses. Hence, everyone must be vigilant and look for Asian Hornets, Tropilaelaps, and Hive beetles. Information on diseases is covered elsewhere, like Beebase. My version is more comprehensive..
A stocking rate of 7 hives per apiary may be sensible, but it is pie in the sky. Sufficient space between apiaries will help prevent disease transmission. This is assuming each colony needs 1 km3 of forage and bees travel no further than 1.5 kilometres from home. Professional beekeepers have to keep more colonies per apiary to make it economically worthwhile.
The crucial skill is spotting when things don’t look right. Healthy larvae are pearly white with a shiny surface and neatly curled up in their cells. Good capped brood is like a well-laid patio of hexagonal pavers that are slightly domed and dull brown (because the cappings contain pollen and wax).
Signs of abnormal/normal brood
Good brood patterns. Many frames don’t look that good.
The frame being held shows lines of empty cells at the position of the wire embedded in the foundation. © Crown copyright
Open brood disease: brood is distorted in its cells and discoloured (from yellow to green-brown); refer to EFB below.
Sealed/closed brood: uneven, sunken, discoloured cappings. The brood may appear flattened in shape with an upturned head (although it looks more like the tip of an abdomen) and may contain a viscous fluid. If you suspect disease, open cells near where the bees have removed the diseased brood. Refer to AFB below.
Bee Appearance and behaviour: Some abnormal things to look for are small bees, bees crawling around the entrance with fluttering wings, unhooked wings resulting in a K shape, deformed wings, bees clambering onto long blades of grass, and buzzing. Dead bees under/on the landing board, piles of heads and abdomens under or on the hive floor, smelly hives, dysentery, bees shaking and looking shiny black, oily looking bees, colony failure to thrive.
Contents - problems
American foulbrood (AFB)
European foulbrood (EFB)
American foulbrood (AFB)
This shows how dead larvae form a dark scale. The manky looking cappings and dark scales suggest AFB. © Crown copyright
AFB causes cell cappings to look manky—initially, the dome darkens, then becomes unevenly sunken and damp. AFB is endemic. It occurs haphazardly every year in the UK and can arise at any time of the year. The colony may die within three weeks of infection.
Larvae are fed spores to brood food but maintain a normal appearance until their cells are capped. The causative organism is a bacterium (Paenibacillus larvae, which is named after the classical term “Paeni,” meaning the “state of mind of pagans;” bacillus denotes the lozenged shape of the bugs). AFB spores remain viable for more than 70 years and are highly resilient.
After the bees seal a cell, the contents rapidly become thick and sticky, it darkens to black, and finally forms an adhesive scale. In the late stages the hive may have an offensive smell.
Tests for AFB
The Ropiness Test: If a match stick is inserted into a gloopy cell, a string of snotty gunk can be pulled out more than 4cm (rope sign); this suggests AFB.
The Holst test is easy to perform
A lateral flow test clinches the diagnosis.
To detect the scale, Hold a frame to eye level and tip it down slightly towards you. Look across the frame.
Infected larvae forming a drawn out viscous string during rope test. © Crown copyright.
Management of AFB
After diagnosing AFB, there is a standing order; no hive stuff can be moved. AFB must be immediately notified to the National Bee Unit (NBU).
When all the bees are home, place each hive in a fire pit 1 metre square and 0.5 metres deep, pour petrol inside, and burn them. Lighting petrol may result in a volcanic eruption; unless you are careful, a pyroclastic flow will singe your eyebrows, so stand upwind.
Beekeepers in North East America have more options. In the past, some performed prophylactic dusting with an antibiotic twice yearly, which suppressed but did not eliminate the problem. In Pennsylvania, contaminated plastic parts can be double-bagged and disposed of at a municipal waste site.
European Foulbrood
Larvae lose their happy white “Michelin tyre advert man” appearance and look melted, distorted, and finally go properly discoloured (cream to yellow to light green brown). Larvae become semi-liquid and dry to a rubbery residue. In their efforts to remove the dead larvae, nurse bees become contaminated and transmit the infection. The responsible bacterium is Melissococcus plutonius. Its name is derived from three words: the Greek term Melissa, meaning honey; Coccus, the spherical shape of the bug; and Pluto, the king of the underworld. It does not form spores and proliferates in the gut, so the larvae starve. Often, EFB lingers in hives and only becomes a problem when the colony is stressed. Robber bees can spread the infection.
Diagnosis of EFB
Images of affected brood. Dark comb can make brood look grey, so reach for your torch. Cell caps can rarely look deformed so that they can resemble AFB. A ropiness test may be abnormal, but the rope is only 1-2 cm long. But essentially, EFB affects open, not sealed brood. A lateral flow test clinches the diagnosis.
Diseased colonies must be destroyed, and the hives burnt, although shook swarming has a favourable effect.
EFB, AFB are Notifiable, they must be reported to the NBU. Should you find signs of foulbrood, take some photos and send them to your regional bee inspector.
To the top of the page
©Crown copyright. burning hive components
©Crown copyright. Discoloured larvae due to EFB.
Varroa destructor
Colonies invariably need regular treatment for varroa, or they collapse and die. Check your bees or play Russian roulette. Varroa is no longer a notifiable infestation (2010). Varroa mites are like sneezes that spread diseases; they inoculate large amounts of viruses, such as the Deformed Wing Virus. It is viruses that kill the colony.
Photo: © Crown copyright. The most significant bug is varroa, followed by Braula, Tropilaelaps, and the weenie circular mite, which feeds on pollen.
Much more about varroa
Acarine (acariosis)
Affected bees often have a reduced lifespan, so if there is a heavy infestation, the colony will dwindle in the spring or when the colony is stressed. Brood up to 9 days old are susceptible to infection. Acarine eggs hatch in 3-4 days. The six-legged larvae live in the tracheae (breathing tubes) and develop through a nymphal stage to the adult male in 11-12 days or to an adult female mite in 14-15 days. The female mites migrate to the hairs on the bee’s legs and, in this way, move to other bees. The mites are too small to see with the naked eye, needing an x40 lens.
© Crown copyright.
Bees in severely affected colonies may be lethargic and reluctant to fly; with K wings, they crawl around the front of the hive. But usually, they look perfectly normal despite mites blocking some of their trachea.
It is not a problem in the UK despite being introduced by some imported queens. Perhaps all the most susceptible bees were wiped out in 1920 in the “Isle of White Disease”.
Internet searches regarding treatment give discordant results. But formic acid and grease patties are effective, and menthol and Apiguard are beneficial. The best management involves re-queening and keeping resistant strains like Buckfast.
© Crown copyright.
Chilled brood
Each cell in the comb has a microclimate, which makes it quite difficult to cool the brood so that it dies. So it is not a problem if you are sensible. When chilled, brood of all ages are affected.
Causes of chilled brood
colony on the brink of starvation
sudden loss of many bees
inspecting for too long/cold
moving too much brood to a nuc
A cold snap in the spring when there are insufficient bees to keep the outermost brood warm (particularly in wooden hives).
Someone at LASI (Surreyuniversity Dept. Social insects) experimented. He left a frame of brood under a hedge and another on top of the work bench overnight. The brood under the hedge remained viable. I’ve read an optimist who purports that unsealed brood can survive several days when kept at room temperature (18 deg.C).
Chilled uncapped brood transitions from grey and brown to black and has a shiny appearance. Eventually, it forms a scale, which the bees easily remove. Larvae stay shiny even though discoloured.
Sacbrood
© Crown copyright.
A viral infection that is usually well tolerated. The first sign is a white tail (the head of the larva) poking out of a cell (which has been uncapped by bees). it turns brown; by this time, it is firm on the outside with a soft center. If you pull a carcass out with tweezers, the shape of the residue takes the vague shape of a Chinese slipper or banana. Severe infestations cause brood cappings to become darkened and uneven. In times of stress, it can contribute to a colony failing. Treatment involves re-queening with a hygienic strain like Buckfast. Sugar solution will give them a boost. When contaminated material like combs is removed, the colony ceases to be infectious after a few weeks.
Chalkbrood
Chalkbrood is a fungal disease. Infections require less than 80% humidity and are not temperature dependent. The humidity in the brood nest can reach 85%, but when they are curing nectar, humidity levels are much lower. The infected cell initially looks fluffy and matures into a white, chalky residue that can be confused with mouldy pollen. However, pollen easily crumbles under pressure. Chalkbrood does not seem to do much harm. Bees deposit the debris outside the entrance or on the hive floor.
Photo © Crown copyright.
Humans
Cabbage stem flea beetles can devastate Oil Seed Rape (OSR).
Apart from giving bees somewhere to live (we’ve cut down all the ancient trees that provided nesting sites) and feeding them with sugar (because we’ve stolen their honey), we haven’t done them any favours.
A dangerous time for queens is when her colony is inspected or manipulated. An example of danger was that after marking a queen, my guru showed me how to run her into her hive through the entrance (a 100% successful method of queen introduction), but the Q had other ideas and was almost lost in the grass. Fortunately, the day was saved, and as a result, I learned how to use this method of queen introduction.
Compare this with Child mortality in Sudan, which is forty deaths per thousand (unless there is a drought or civil war)—way less than that of queen bees.
Queen mating. One might suspect that this is dangerous, but if there are apiaries nearby, it is exceptional that a queen fails to return.
Humans introduce foreign bugs like varroa; realistically, it is only a matter of time before Asian hornets become established.
Some frequencies of electromagnetic fields, like those from a Wifi router, can interfere with bees’ navigation in the same way as some pesticides. So, even innocuous things can interfere with bees.
Insecticides: Consider the Cabbage Stem Flea beetle, which is a threat to brassica crops like Oil Seed Rape (OSR) (a valuable source of nectar and pollen). In the past, farmers controlled it with Phrythroid-based insecticides. When these were no longer effective, they turned to neonicotinoid seed dressing. Only when scientists discovered that these interfere with bee navigation was their use almost wholly banned. Understandably, farmers protested greatly, but some have found that Integrated Pest Management is effective.
Vairimorpha - Nosema
Nosema spores. Photo ©Crown copyright.
The diagnosis is made using microscopy at x400 magnification. The spores are much smaller than pollen. Look at the photo—their shape resembles arborio rice.Symptoms like winter deadouts and failure to build up in the spring are easily attributed to some other cause.
Older bees carry a larger fungal load than young bees. Bees are infected when they do housework. If young bees are affected, it signifies severe disease. Ultimately, nurse bees can not produce brood food, and the queen stops laying eggs. The spores left on their own are viable for 12 months.
Vairimorpha is defined (based on genetic markers) as a genus of microsporidian parasites such as nosema (Nosema = Latin for disease). In 2024, there is a dispute as to whether Varimorphia is synonymous with nosema. Beekeepers refer to them simply as Nosema and fungi, which are safe bets.
Nosema lives in gut cells and produces millions of spores, which remain viable in a dead bee for 4.5 years. Since it lives in the gut, malnutrition and dysentery arise.
A queen may unwittingly infect her colony when she mates with a diseased drone. Whenever beekeepers see dysentery, they wonder if it is Nosema, but it rarely is. There are four species: N. apis, N. ceranae (infections are respectively called type A and type C nosemosis), one in Africa called N. neumanni, and N. bombis that only affects bumble bees.
Most of the time, the bees cope with the infection, so it is subclinical. But it causes symptoms in times of stress, such as in the spring, when bees can not go out on cleansing flights.
Most commonly, the colony fails to thrive and produces a poor honey crop, and diarrhea may be visible on top of the frames (brown splatters). With N. apis, spore levels fall dramatically over the summer. However, the commoner N. ceranae (imported from Asia) remains toxic and active all year, so colonies dwindle over the summer.
Treatment of Nosemosis
Thymol added to sugar syrup is considered a good preventative measure, and acetic acid fumigation will destroy spores. Management involves moving the bees onto fresh comb, queen replacement with a young queen (which. can be very beneficial), and cleaning everything that might be contaminated. People say a Bailey comb change is better than a shook swarm because fewer bees get squashed. Spores under freezing conditions remain viable for up to a year. A 60 deg.C wash will disinfect a bee suit contaminated with N apIs, but N ceranae is far more resilient, requiring 60 degrees for six hours. Hence, it must be cleaned and soaked in hypochlorite or hypochlorous acid. Trickling oxalic acid twice is a promising but unlicensed treatment.
In America, nosemosis is treated with Fumagillin, which only suppresses the infection. It has some benefits against N. Apis but may aggravate Type C nosemosis. It lingers in combs and may harm human health. It is not used in the UK.
HiveAlive is a supplement containing thymol and seaweed that claims to boost colonies and reduce winter losses, particularly in colonies with Nosema. The manufacturer says seaweed is used in human medicines, but I can find no evidence of this in the British National formulary apart from as a wound dressing. There is no consistent scientific evidence that herbal remedies such as Hivealive and Nosevit) are effective. But anecdotal evidence is all positive.
Randy Oliver diplomatically writes about Hivealive - “The product makes a number of claims, the ability to suppress nosema among them. However, careful inspection of the supportive studies suggests that the claims may be a little bit wistful. The most supportive study was run in Greece by Charistos [[18]]; however, the results are somewhat “polished” in the sales brochures. What beekeepers are really interested in is the effect of treatment on colony strength and survival ― despite the application of the treatment, Charistos’ study found no appreciable differences in colony strengths between the test and control groups during the first eight months (November through June). By the next November, the colonies had dwindled to only 3-4 frame strength ― too small for me to consider any subsequent results to be meaningful. I’d need to see stronger supportive data before making any further assessments of the product. So until I can review further supportive data on Hive Alive, I am unable to provide an assessment.”.
A 2023 study compared several herbal probiotic remedies and found they had negative or nil efficacy.
BBKA basic exam: How to take a sample of worker bees in a suitable container
Method 1
On a day when the bees are flying well, block the entrance with some grass or a piece of foam rubber. After a short while,
the returning foragers will be clustered over the entrance so you can scoop up the required number in a suitable container.
Method 2
Take a drink carton and cut off both ends to make a tube. Put a clear plastic bag over one end and rattle the cardboard tube
against the entrance. The bees will come out and instinctively fly to the light – into the bag.
Method 3
Put a matchbox over some bees at the brood nest's periphery (to catch mature bees). Wiggle the matchbox sleeve back into position.
Method 4
Use a sample of dead bees.
Collecting 30 bee samples for disease analysis
Wax moth
These come in little and large versions, i.e. lesser and greater. They run fast, with swept-back wings. The Lesser ones resemble clothes moths (but are 13 mm long). The Greater ones are 15–20 mm long, depending on their sex. When disturbed, they run to find a dark place rather than fly. Bees normally control them. But the moths run amok if they find undefended combs. The larvae wriggle through the comb in a straight line, leaving a trail of frass. If they nibble the cappings, they expose the bee larvae. This is called bald brood. Tapping a frame sometimes makes a wax moth larva wiggle into view.
A trail of frass left by a wax moth as it tunnelled through the comb.
Holes from wax moth larvae boring through polystyrene
Greater wax moth larva © Crown copyright
The larvae treat the polystyrene (PS) as a playground and can burrow through the total thickness of a wall. They are like meal worms that eat polystyrene as part of a balanced diet. But it takes plenty of worms to eat a poly hive. The reality is that they turn it into microplastic.
It is commonly believed that in feral hives, wax moths are the bees’ friends as they clear up old comb that may harbour disease and so turn bee poop into moth poop. That may be correct in temperate climates, but are highly destructive in the tropics.
Before you store waxy frames, freeze them overnight or fumigate them with acetic acid. Store frames in well-sealed containers or place them in a bright, airy, inhospitable place.
Entrance Loyalty - The Injun Joe effect
This describes how flying bees react when their usual entrance is blocked, even if they used an alternative entrance just a minute before. They are rigidly faithful to the position where their home entrance ought to be. If you have the good fortune to have a bee-proof bee-shed, this should never be an issue.
Injun Joe is a character in the book Tom Sawyer. He accidentally became locked in some caves. Subsequently, he was found dead beside the door that sealed the entrance. So rather than grope around to find another way out of the cave system (there was one), he vainly scratched away at the door with his knife until he died.
Upper photo. Several colonies contributed to this disaster. The bees entered via an upper entrance and filled up with honey and could not find their way out. Fortunately, all the colonies survived the winter.
I can n’t help but speculate why the bees die so rapidly in this scenario. Perhaps since they were unable to offload the honey from their crops they became dehydrated. The honey crop is impermeable, so my theory would necessitate honey entering their gut. The hypertonic honey solution would “pull water” out of the bee’s body. Contrast this with other circumstances, like when bees that are not foragers get marooned in some boxes; they stay alive for weeks.
The lower photo shows how, seventeen days after installing a Swarm trap (in this instance, I used my DIY manipulation board), bees are still trying to use the bottom entrance. Presumably, there are a similar number of bees trying to get out.
To help them adapt to the new entrance, lean a broad plank against the hive with its tip just below the new entrance. Never put the Swarm trap above more than one box.
Hive Toleater
There is compelling evidence for this elusive pest. It has a wide distribution in the Southern and Northern hemispheres and is a scourge where grass surrounds hives. Beekeepers without grass are fortunate and are not aware of this pest. The creature is capable of living on a meagre diet, it has teeth as hard as diamonds and stomach acid so strong that it can digest ferrous objects.
Wasps (Vespula vulgaris)
A large wasp’s nest
These are the top carnivores of the insect world. (discounting European and Asian hornets). Wasps do some pollination work, eat pests like aphids, and maintain the natural insect balance. Like bees, their colonies build up through the summer, but they climax in October when new queen wasps mate and hibernate. Normally, larvae reward their carers with a sweet solution. In the autumn, wasps have fewer larvae to give them a sugar hit, so they turn to eating honey and fruit. Eventually, the remaining worker wasps lose their modus operandi and become bad-tempered.
They can wipe out honeybee colonies. To prevent this, trap wasps or place a protective device over the hive entrance.
If your nucs are safe and you are only troubled by a few wasps, you may decide not to take action. But be watchful.
Jam jar traps work well. Punch a hole through the lid with a chisel (less than 5.5 mm wide). This is better than a larger circular hole as it prevents larger insects like European hornets from getting trapped. Wasps can squeeze through a 5 mm round hole. I hate seeing wasps scrabbling around trying to escape a trap, but needs must. Sprinkle traps around your apiary when wasps are flitting around. Bees do not eat jam (strawberry basics). Once I put a trap beside a hive entrance and caught no bees. If you don’t believe me, add a little vinegar to your bait.
Wasps can overwhelm small colonies despite traps. There may be only a few wasps around your apiary, despite this, a box can be thronging with wasps. I’ve read that the action of last resort is to move a susceptible colony somewhere safe. Devices like WaspOut and HiveGate claim success. They provide no defence against robbing.
Simple traps made of a jam jars decimates wasps.
The trap in the photo contains a lot more jam than necessary. Enough to make the water cloudy works fine. They die quicker if you add a drop of detergent.
Sugar syrup works, probably, as well as any other bait, but don’t put it near a hive entrance. It is very convenient to use some syrup being fed to the bees. I imagine that this sounds daft to other beekeepers, as bees like sugar. But bees can barely smell it through a small hole, whereas wasps find it irresistible. I have audited my catch, and a jar trap collected 22 non-wasps per 1000. Nine of them were European hornets. The rest may have been flies or bees. They were too decomposed to be certain.
For hornets, including Asian hornets, someone (sorry, I can’t remember who) recommends this mix:
1 litre of water
1 kg sugar
2 or 3 tbs of jam
A glug or 2 of honey washings from washing equipment and a magic ingredient — 1/4 tsp of dried yeast.
Ferment until bubbling (with a proper release cap). In summer, this only takes a few days. “Excellent for holding the attention of hornets, but might not be quite as good at attracting them (Trappit has a strong smell that emanates well).”
HiveGate
HiveGate is a tunnel (blue) from the hive entrance (flat end) into the hive. Wasps enter an area with more bees (the hexagonal area) and are easily overwhelmed. Fitting it entails some precision DIY.
Further information
Waspout
Thorne manufactures and sells this under licence. The wood is machined so that it fits the hive entrance. The bees enter the tubes at the ends. It works.
I bodged this “Hive Shield” prototype. The concept is that the wasps are attracted to the smell of the colony that emanates through the holes in front of the entrance. The insects get confused by the transparent area. Bees are very persistent in their efforts to get in and buzz their wings. Eventually, they find their way through the narrow entrance at the side, which is concealed by a bit of duct tape. Guards sit on the outside around the holes.
Notwithstanding, jam jar traps cause distress to wasps they are incredibly effective and, in my experience, render entrance devices obsolete. Loads of wasps crawling and flitting around the apiary are unpleasant.
Spotty Brood
Usually, the cause of spotty brood is unknown, and if the colony is thriving, it does not seem to do any harm and may rectify itself. If it is severe or persists or the colony fails to thrive, ask an experienced beekeeper or National Bee Unit (NBU) regional bee inspector to visit. Spotty brood may be due to foulbrood, so do a disease inspection.
The photo shows disorganised, small bunches or single cells surrounded by empty comb. Diseased larvae are rapidly removed, which makes disease detection difficult. Bees that exhibit hygienic behaviour are even more problematic when, under other circumstances, it is a desirable trait.
Causes of Spotty brood
The workers remove the inbred larvae if the queen mates with her drones.
Spotting is rarely due to a poor queen. But the pattern often normalises.
If there is a lack of pollen, bees may cannibalise eggs and young larvae.
In the autumn, the queen will not lay so many eggs to fill the gaps, so her poor laying pattern from long ago is revealed.
It can arise when the queen lacks space to lay. If the queen is laying in cells shortly after they are vacated, it is not a queen problem.
Exposure to pesticides.
Stearin contaminated wax foundation
Removal of larvae that are diploid (homozygous alleles for the sex gene; two of the same alleles).
Rusty Burlew explains diploidy.
Poor queen cells
Top pictures: A reasonably nice-looking queen cell was a dud. Some pesticides, like diflubenzuron, hurt larval forms.
To become a good queen, the QC must be cared for by plenty of nurse bees, with loads of pollen and sugar at hand, she may become a rotter. Swarming occurs when the bees judge that the conditions are ideal; hence, swarm cells generally produce good queens.
Dysentery or Busting bowels
Just like humans, diarrhoea is a symptom rather than a disease. Beekeepers refer to diarrhoea as dysentery, which is a travesty if an infectious cause has not been identified. It may be due to fermented sugar or, rarely, nosema. The abdomen of winter bees is almost full of faeces by the spring. The critical tipping point is when a third of their body weight is pooh, and the pooh contains 20% water. A bee in the cluster will die rather than pooh. Other bees soil the entrance if the weather prevents them from making cleansing (poohing) flights. With severe diarrhoea, they pooh on the frames and up the front of the hive.
Chronic Bee paralysis
Chronic Bee Paralysis may have caused the Isle of Wight disease, which wiped out many colonies in the early 1920s. However, microsporidiosis (nosema) and acarine mites have also been implicated.
It can be severe and cause winter losses. Afflicted bees die after three days.
I’ve seen a few bees that were black as the ace of spades, but the colonies stayed happy. It is highly infectious and becoming more common. Treatment involves giving them extra space (the infection is spread by contact) and feeding them syrup. For more info - NBU
Affected bees display some of these signs:
hair loss
look black and oily
cling to bits of grass
huddle on the top bars and do not move when smoked
have bloated abdomens
crawl around the entrance, maybe in large numbers
dislocated wings — K appearance
doing a wing /body tremble.
Unexplained colony losses
Occasionally, a colony dwindles and dies, particularly in the winter. Amazingly, pandemics are infrequent, considering how many bees live together without social distancing. To check for Nosema, ask whether someone in your association does microscopy. There are ways to reduce winter losses:
Have a queen born in the autumn or spring, depending on who you believe (or keep varroa tolerant bees).
Start treatment for varroa before mid-August and make sure it works. Thymol-based treatments are capricious, and even in perfect weather, they may not be effective.
Treat varroa in the autumn, winter, and spring.
As they go into winter, make sure a colony is sufficiently numerous and healthy
Dampness is a leading cause of losses. Some people with wooden hives increase ventilation by raising the crown board with matchsticks. Rusty Burlew endorses a moderate amount of ventilation. Others, like David Evans, put a 50 mm insulation sheet above the crown board and do not use top ventilation.
Some people use wraps to reduce heat losses. They would do better to use a Paradise Honey hive!
In extreme climates, some people overwinter their hives in barns. Colonies in Beeboxes stay outside, but the entrances must be kept free of snow.
Heater Bee Holes
Not a problem. This area of drone brood is shot through with holes for heater bees. It happens like this. Bees go in the holes head first, generate heat in their flight muscles, and pump the hot blood from their thorax to their heads. Other heater bees press their hot bodies down on the comb. Generating heat is a very energy-intensive task, and they can only keep it up for 30 minutes before resting and drinking some honey. When we inspect a hive and the hive and frames cool. Think how much stress we cause.
Braula coeca
This wingless fly looks more like a louse. Only 1.5–2 mm across, it sits on a bee's head (particularly the queen, as she is constantly being fed) and reaches right down to the bee’s mouth to steal food. It does not harm the colony.
Braula look like reddy brown hairy dinner plates; see Beeaware - it is entirely different from Varroa. The larval and pupal stages occur in tunnels in the cappings, which can spoil the appearance of the comb. Braula must be rare as it is susceptible to most varroa treatments.
Photo: minute red dot © Crown copyright.
Pesticides & herbicides
Chemicals enable farmers to provide us with affordable and nutritious food. Pest control is expensive, so farmers prefer not to treat it unless they think it is necessary. However, they often spray prophylactically.
My concern is that the manufacturers do not have to do long-term toxicity studies. Moreover, the active substance may not be toxic to bees, but excipients such as surfactants are. Surfactants cause insects to asphyxiate.
Ants
Ants are well-organised like bees. When an ant finds sugar syrup, she summons her buddies so that they can drown in the syrup. If ants are a problem, put a pot of water under each of the legs of the hive stand or smear grease (horticultural or car) around the hive legs. Cinnamon repels them.
Damp
Wooden hives get sodden in the winter. Not only can moisture pass through the outside, but bees produce as much as 4 gallons (ca. 18 litres) of water during the winter through respiration. In BeeBoxes, water condenses on the walls and trickles through the Open Mesh floor.
If dampness does occur, the issue is with the beekeeper. The picture shows dead bees on the floor because I had forgotten to remove a large sac of bakers fondant I’d placed over the frames in the autumn. The hive suffered from a lot of condensation, and by the spring, only two frames of brood and the Q survived.
However, if I feed the fondant using my DIY crown board, there is no problem so long as there is insulation above it.
Colony Collapse Disorder
It is a problem in America and some European countries, but in not the UK.
Unexpectedly, hives become empty, with no sign of bees having died. Just the queen and a handful of nurse bees remain, with plenty of stores and some capped brood. Whilst there are some associated factors, no cause is known; ergo, the cause must be multifactorial. There have been episodic reports of similar issues since 1869. Currently, Americans are the most severely affected, and shipping bees hundreds of miles between crops and periods of restriction to mono-floral pollen sources can’t be good. Beekeepers in many countries were impacted in 2007. UK beekeepers lost 30% of their colonies. However, the British losses did not fit the criteria for CCD because of pollen and stores, so we named it the Mary Celeste Syndrome.
Prodromal signs of CCD are a change in bowel function, reluctance to take sugar syrup, and the age structure of workers becoming younger……. Helpful.
Mice and Shrews
© Crown copyright.
Wooden hives have an almost impenetrable mouse guard. © Crown copyright.
Mice find their way into hives in the autumn when they want a dry, warm place to pass the winter. They can get through a 9 mm slit (but not a 9 mm circular passage), so there is no problem with Beebox hives. The entrance of a wooden hive is fitted with a mouse guard during the winter, consisting of a sheet of metal or wood with circa 9 mm holes. So the bees live in Fort Knox. Once inside a hive, mice eat honey, and shrews eat half their body weight in bees every day and make a thorough mess. Signs of their habitation include an area of bogginess above the OMF that does not ping like a musical instrument. Sublimated OA kills them or drives them out. In the spring, I’ve seen middens under hives, which consist of bee heads and abdomens.
Damage to comb and debris on the OMF caused by a mouse © Crown copyright.
Green woodpeckers
Woodpeckers can be a problem in freezing weather when they cannot access their everyday food (ants). They drill into unprotected hives. To avert this, surround each hive with chicken wire, leaving a gap of 5–6 inches from the hive walls. But metal mesh gouges polystyrene. An alternative is to dangle tough plastic sheets off the roof so that the bird cannot get a foothold. But with a poly hive, they will still attempt to drill through the roof. Dangling CDs around the apiary distracts woodpeckers. Woodpeckers have only learned about tasty bees in some areas, so ask around. I’ve never taken precautions, although I’ve seen and heard the birds. I fancy they might find it bothersome to drill through plastic frames.
Woodpecker damage © Crown copyright.
Aberrations
Odd things happen that never used to happen; nobody knows why.
They produce supersedure and emergency QC at the same time.
Worker brood dotted with drone cells.
Queens have a reduced life expectancy and die for no apparent reason. She may stop laying for a few days and then die, so there are no emergency queen cells.
Frequent supersedure of queens after introduction
They swarm on a supersedure cell or emergency cells
They abscond for no reason
Queen failure. The colony development stalls at around three frames of brood; the queen stops laying for a few weeks and then dies.
Queens fail to mate despite good weather.
If you have read all this, and you mutter, “Oh no, my bees never suffer anything like this”. You have not kept bees for long enough. Sigmund Freud would say it’s something to do with sex.
Robbing
The lips on a Paradise hive make for a very positive fit. However, if they are misaligned, the fit is worse than poor.
Foreign Threats
Tropilaelaps
Varroa on the left and Tropilaelaps on the right .
© Crown copyright.
This is a mite that lives in Asia and wreaks havoc like varroa. It is not present in the UK. Smaller than varroa, it is 0.7 mm long and orange/brown with a more elongated lozenge-shaped body — with the head at one end and legs at its sides. So they won't be easy to spot on varroa boards without a magnifying glass. They reproduce more rapidly than varroa and kill a colony within 2–3 months. It used to be thought that they could not survive a brood break longer than five days or a cold climate. However, they have spread to Russia and live longer when they attach themselves to bees. Tropilaelaps cannot feed on adult bees, but is very similar to varroa in its consequences. Just like varroa: It feeds on larvae and reproduces in sealed brood, favouring drone brood. Some bees emerge malformed. Treatments have not been adequately assessed. Brood breaks should hit this bug, as well as repeat sublimations of oxalic acid (not trickled). It is a notifiable disease.
Small hive beetle
© Crown copyright.
Not present in the UK. Larvae of these weenie beetles munch combs and make a thorough mess. Exposed honey ferments, resulting in an ethanolic smell. Females lay their eggs in nooks and crannies. Subsequently, the eggs grow into wax moth-sized larvae., which pupate in the soil surrounding the hive. Adults are brown, maturing to black, 1/3 the size of a bee, and can retract their legs like a tortoise, so they are impervious to the bees’ attacks. They do not form frass like wax moths. Bees try to remove the beetle by dropping them outside. Alternatively, they corral them in corners. But if the guard bees are offered some nectar, they let the beetles out.
Asian hornets
Asian hornets are prevalent in France, Guernsey and elsewhere. They are a severe nuisance. They eat solitary bees and other insects, not just honey bees. More information:
Asian hornets are not aggressive unless threatened. Their stingers are 6 mm long, so a standard bee suit does not provide protection. To find a nest, Bee Inspectors do something like this: set up feeding stations and observe which direction the hornets fly on their way home. By moving the feeding stations step by step towards the nest and triangulating results, the nest can be detected within 24 hours. Radio tags make it even quicker.
Top photo - a hornet nest was in this hedge beside a footpath.
Retrieving an Asian hornet’s nest.
© Crown copyright.
Vespa velutia at their nest entrance © Crown copyright.
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Asian hornet *
Hopefully, you have heard all about these hornets already. Extremely effective predators, they are renowned for hawking at the entrance of hives, catching bees as they fly in and out. The colony can become so frightened that they stop foraging and die of starvation. Hornet queens start out making a low-level nest. Once it reaches the size of a tennis ball, the colony forms a large secondary nest, usually high in trees.
The crucial identification features are yellow legs and a brown abdomen with a yellow band towards the end. So far, crack teams have managed to destroy all the nests that have been found in the UK. If you see this hornet, take a photo and send a report using the Asian Hornet App. -
Giant Asian / Japanese / murder hornet *
It has been seen in the USA, but not in Europe. Not only the largest hornet but also the most destructive and frightening, much more so than Asian hornets. Bees have no defence; a few hornets can eat a colony’s brood in one sitting with honey for dessert. Living in areas with trees and woodland, they nest in holes in the ground that are difficult to find. When their nest is threatened, several hornets attack, each delivering several stings and, hence, a large amount of venom. A sting has been described as like a “hot needle being driven into my leg”. So, people who live in endemic areas may suffer long-lasting anxiety.
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European hornet *
Native European hornets eat a few bees, but they are not a big problem. They eat a varied diet, including fruit and other insects, and are an important part of the ecosystem. Whilst these hornets look fearsome, they only sting in defence of their nest. Their venom causes less pain than other hornets. They nest in cavities more than two meters off the ground and are attracted to light, which makes them more likely to be persecuted. Indeed, 60 years ago, they were rare in the UK. Their range has extended, and they are common in Kent, Surrey, and Sussex. They are 1 cm shorter than a Giant Asian hornet.
More information about Asian hornets
Graph showing the annual average number of colonies in the UK that died during the winter
Graph from BBKA.
Full details. The one brave beekeeper was me! It was my only loss in 9 years.
Wikipedia - a comprehensive list of bee diseases
Further reading, photos and insurance
Insurance
British BeeKeepers Association (BBKA) beehive and colony insurance. Information about beekeeping.
Register with Beebase (National Bee Unit) so that you will be informed if there is a disease outbreak near your apiary.
Next page, Varroa
Page 8.
